blob: b337d6f29098bfda5a4f1732ce022d0413fa3f2e [file] [log] [blame]
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/*
* Common eBPF ELF object loading operations.
*
* Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
* Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
* Copyright (C) 2015 Huawei Inc.
* Copyright (C) 2017 Nicira, Inc.
* Copyright (C) 2019 Isovalent, Inc.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <libgen.h>
#include <inttypes.h>
#include <limits.h>
#include <string.h>
#include <unistd.h>
#include <endian.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <asm/unistd.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/filter.h>
#include <linux/list.h>
#include <linux/limits.h>
#include <linux/perf_event.h>
#include <linux/ring_buffer.h>
#include <linux/version.h>
#include <sys/epoll.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/vfs.h>
#include <sys/utsname.h>
#include <sys/resource.h>
#include <libelf.h>
#include <gelf.h>
#include <zlib.h>
#include "libbpf.h"
#include "bpf.h"
#include "btf.h"
#include "str_error.h"
#include "libbpf_internal.h"
#include "hashmap.h"
#ifndef EM_BPF
#define EM_BPF 247
#endif
#ifndef BPF_FS_MAGIC
#define BPF_FS_MAGIC 0xcafe4a11
#endif
#define BPF_INSN_SZ (sizeof(struct bpf_insn))
/* vsprintf() in __base_pr() uses nonliteral format string. It may break
* compilation if user enables corresponding warning. Disable it explicitly.
*/
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
#define __printf(a, b) __attribute__((format(printf, a, b)))
static struct bpf_map *bpf_object__add_map(struct bpf_object *obj);
static const struct btf_type *
skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
static int __base_pr(enum libbpf_print_level level, const char *format,
va_list args)
{
if (level == LIBBPF_DEBUG)
return 0;
return vfprintf(stderr, format, args);
}
static libbpf_print_fn_t __libbpf_pr = __base_pr;
libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn)
{
libbpf_print_fn_t old_print_fn = __libbpf_pr;
__libbpf_pr = fn;
return old_print_fn;
}
__printf(2, 3)
void libbpf_print(enum libbpf_print_level level, const char *format, ...)
{
va_list args;
if (!__libbpf_pr)
return;
va_start(args, format);
__libbpf_pr(level, format, args);
va_end(args);
}
static void pr_perm_msg(int err)
{
struct rlimit limit;
char buf[100];
if (err != -EPERM || geteuid() != 0)
return;
err = getrlimit(RLIMIT_MEMLOCK, &limit);
if (err)
return;
if (limit.rlim_cur == RLIM_INFINITY)
return;
if (limit.rlim_cur < 1024)
snprintf(buf, sizeof(buf), "%zu bytes", (size_t)limit.rlim_cur);
else if (limit.rlim_cur < 1024*1024)
snprintf(buf, sizeof(buf), "%.1f KiB", (double)limit.rlim_cur / 1024);
else
snprintf(buf, sizeof(buf), "%.1f MiB", (double)limit.rlim_cur / (1024*1024));
pr_warn("permission error while running as root; try raising 'ulimit -l'? current value: %s\n",
buf);
}
#define STRERR_BUFSIZE 128
/* Copied from tools/perf/util/util.h */
#ifndef zfree
# define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
#endif
#ifndef zclose
# define zclose(fd) ({ \
int ___err = 0; \
if ((fd) >= 0) \
___err = close((fd)); \
fd = -1; \
___err; })
#endif
static inline __u64 ptr_to_u64(const void *ptr)
{
return (__u64) (unsigned long) ptr;
}
enum kern_feature_id {
/* v4.14: kernel support for program & map names. */
FEAT_PROG_NAME,
/* v5.2: kernel support for global data sections. */
FEAT_GLOBAL_DATA,
/* BTF support */
FEAT_BTF,
/* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
FEAT_BTF_FUNC,
/* BTF_KIND_VAR and BTF_KIND_DATASEC support */
FEAT_BTF_DATASEC,
/* BTF_FUNC_GLOBAL is supported */
FEAT_BTF_GLOBAL_FUNC,
/* BPF_F_MMAPABLE is supported for arrays */
FEAT_ARRAY_MMAP,
/* kernel support for expected_attach_type in BPF_PROG_LOAD */
FEAT_EXP_ATTACH_TYPE,
/* bpf_probe_read_{kernel,user}[_str] helpers */
FEAT_PROBE_READ_KERN,
/* BPF_PROG_BIND_MAP is supported */
FEAT_PROG_BIND_MAP,
__FEAT_CNT,
};
static bool kernel_supports(enum kern_feature_id feat_id);
enum reloc_type {
RELO_LD64,
RELO_CALL,
RELO_DATA,
RELO_EXTERN,
};
struct reloc_desc {
enum reloc_type type;
int insn_idx;
int map_idx;
int sym_off;
bool processed;
};
struct bpf_sec_def;
typedef struct bpf_link *(*attach_fn_t)(const struct bpf_sec_def *sec,
struct bpf_program *prog);
struct bpf_sec_def {
const char *sec;
size_t len;
enum bpf_prog_type prog_type;
enum bpf_attach_type expected_attach_type;
bool is_exp_attach_type_optional;
bool is_attachable;
bool is_attach_btf;
bool is_sleepable;
attach_fn_t attach_fn;
};
/*
* bpf_prog should be a better name but it has been used in
* linux/filter.h.
*/
struct bpf_program {
const struct bpf_sec_def *sec_def;
char *sec_name;
size_t sec_idx;
/* this program's instruction offset (in number of instructions)
* within its containing ELF section
*/
size_t sec_insn_off;
/* number of original instructions in ELF section belonging to this
* program, not taking into account subprogram instructions possible
* appended later during relocation
*/
size_t sec_insn_cnt;
/* Offset (in number of instructions) of the start of instruction
* belonging to this BPF program within its containing main BPF
* program. For the entry-point (main) BPF program, this is always
* zero. For a sub-program, this gets reset before each of main BPF
* programs are processed and relocated and is used to determined
* whether sub-program was already appended to the main program, and
* if yes, at which instruction offset.
*/
size_t sub_insn_off;
char *name;
/* sec_name with / replaced by _; makes recursive pinning
* in bpf_object__pin_programs easier
*/
char *pin_name;
/* instructions that belong to BPF program; insns[0] is located at
* sec_insn_off instruction within its ELF section in ELF file, so
* when mapping ELF file instruction index to the local instruction,
* one needs to subtract sec_insn_off; and vice versa.
*/
struct bpf_insn *insns;
/* actual number of instruction in this BPF program's image; for
* entry-point BPF programs this includes the size of main program
* itself plus all the used sub-programs, appended at the end
*/
size_t insns_cnt;
struct reloc_desc *reloc_desc;
int nr_reloc;
int log_level;
struct {
int nr;
int *fds;
} instances;
bpf_program_prep_t preprocessor;
struct bpf_object *obj;
void *priv;
bpf_program_clear_priv_t clear_priv;
bool load;
enum bpf_prog_type type;
enum bpf_attach_type expected_attach_type;
int prog_ifindex;
__u32 attach_btf_id;
__u32 attach_prog_fd;
void *func_info;
__u32 func_info_rec_size;
__u32 func_info_cnt;
void *line_info;
__u32 line_info_rec_size;
__u32 line_info_cnt;
__u32 prog_flags;
};
struct bpf_struct_ops {
const char *tname;
const struct btf_type *type;
struct bpf_program **progs;
__u32 *kern_func_off;
/* e.g. struct tcp_congestion_ops in bpf_prog's btf format */
void *data;
/* e.g. struct bpf_struct_ops_tcp_congestion_ops in
* btf_vmlinux's format.
* struct bpf_struct_ops_tcp_congestion_ops {
* [... some other kernel fields ...]
* struct tcp_congestion_ops data;
* }
* kern_vdata-size == sizeof(struct bpf_struct_ops_tcp_congestion_ops)
* bpf_map__init_kern_struct_ops() will populate the "kern_vdata"
* from "data".
*/
void *kern_vdata;
__u32 type_id;
};
#define DATA_SEC ".data"
#define BSS_SEC ".bss"
#define RODATA_SEC ".rodata"
#define KCONFIG_SEC ".kconfig"
#define KSYMS_SEC ".ksyms"
#define STRUCT_OPS_SEC ".struct_ops"
enum libbpf_map_type {
LIBBPF_MAP_UNSPEC,
LIBBPF_MAP_DATA,
LIBBPF_MAP_BSS,
LIBBPF_MAP_RODATA,
LIBBPF_MAP_KCONFIG,
};
static const char * const libbpf_type_to_btf_name[] = {
[LIBBPF_MAP_DATA] = DATA_SEC,
[LIBBPF_MAP_BSS] = BSS_SEC,
[LIBBPF_MAP_RODATA] = RODATA_SEC,
[LIBBPF_MAP_KCONFIG] = KCONFIG_SEC,
};
struct bpf_map {
char *name;
int fd;
int sec_idx;
size_t sec_offset;
int map_ifindex;
int inner_map_fd;
struct bpf_map_def def;
__u32 numa_node;
__u32 btf_var_idx;
__u32 btf_key_type_id;
__u32 btf_value_type_id;
__u32 btf_vmlinux_value_type_id;
void *priv;
bpf_map_clear_priv_t clear_priv;
enum libbpf_map_type libbpf_type;
void *mmaped;
struct bpf_struct_ops *st_ops;
struct bpf_map *inner_map;
void **init_slots;
int init_slots_sz;
char *pin_path;
bool pinned;
bool reused;
};
enum extern_type {
EXT_UNKNOWN,
EXT_KCFG,
EXT_KSYM,
};
enum kcfg_type {
KCFG_UNKNOWN,
KCFG_CHAR,
KCFG_BOOL,
KCFG_INT,
KCFG_TRISTATE,
KCFG_CHAR_ARR,
};
struct extern_desc {
enum extern_type type;
int sym_idx;
int btf_id;
int sec_btf_id;
const char *name;
bool is_set;
bool is_weak;
union {
struct {
enum kcfg_type type;
int sz;
int align;
int data_off;
bool is_signed;
} kcfg;
struct {
unsigned long long addr;
/* target btf_id of the corresponding kernel var. */
int vmlinux_btf_id;
/* local btf_id of the ksym extern's type. */
__u32 type_id;
} ksym;
};
};
static LIST_HEAD(bpf_objects_list);
struct bpf_object {
char name[BPF_OBJ_NAME_LEN];
char license[64];
__u32 kern_version;
struct bpf_program *programs;
size_t nr_programs;
struct bpf_map *maps;
size_t nr_maps;
size_t maps_cap;
char *kconfig;
struct extern_desc *externs;
int nr_extern;
int kconfig_map_idx;
int rodata_map_idx;
bool loaded;
bool has_subcalls;
/*
* Information when doing elf related work. Only valid if fd
* is valid.
*/
struct {
int fd;
const void *obj_buf;
size_t obj_buf_sz;
Elf *elf;
GElf_Ehdr ehdr;
Elf_Data *symbols;
Elf_Data *data;
Elf_Data *rodata;
Elf_Data *bss;
Elf_Data *st_ops_data;
size_t shstrndx; /* section index for section name strings */
size_t strtabidx;
struct {
GElf_Shdr shdr;
Elf_Data *data;
} *reloc_sects;
int nr_reloc_sects;
int maps_shndx;
int btf_maps_shndx;
__u32 btf_maps_sec_btf_id;
int text_shndx;
int symbols_shndx;
int data_shndx;
int rodata_shndx;
int bss_shndx;
int st_ops_shndx;
} efile;
/*
* All loaded bpf_object is linked in a list, which is
* hidden to caller. bpf_objects__<func> handlers deal with
* all objects.
*/
struct list_head list;
struct btf *btf;
/* Parse and load BTF vmlinux if any of the programs in the object need
* it at load time.
*/
struct btf *btf_vmlinux;
struct btf_ext *btf_ext;
void *priv;
bpf_object_clear_priv_t clear_priv;
char path[];
};
#define obj_elf_valid(o) ((o)->efile.elf)
static const char *elf_sym_str(const struct bpf_object *obj, size_t off);
static const char *elf_sec_str(const struct bpf_object *obj, size_t off);
static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx);
static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name);
static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr);
static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn);
static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn);
static int elf_sym_by_sec_off(const struct bpf_object *obj, size_t sec_idx,
size_t off, __u32 sym_type, GElf_Sym *sym);
void bpf_program__unload(struct bpf_program *prog)
{
int i;
if (!prog)
return;
/*
* If the object is opened but the program was never loaded,
* it is possible that prog->instances.nr == -1.
*/
if (prog->instances.nr > 0) {
for (i = 0; i < prog->instances.nr; i++)
zclose(prog->instances.fds[i]);
} else if (prog->instances.nr != -1) {
pr_warn("Internal error: instances.nr is %d\n",
prog->instances.nr);
}
prog->instances.nr = -1;
zfree(&prog->instances.fds);
zfree(&prog->func_info);
zfree(&prog->line_info);
}
static void bpf_program__exit(struct bpf_program *prog)
{
if (!prog)
return;
if (prog->clear_priv)
prog->clear_priv(prog, prog->priv);
prog->priv = NULL;
prog->clear_priv = NULL;
bpf_program__unload(prog);
zfree(&prog->name);
zfree(&prog->sec_name);
zfree(&prog->pin_name);
zfree(&prog->insns);
zfree(&prog->reloc_desc);
prog->nr_reloc = 0;
prog->insns_cnt = 0;
prog->sec_idx = -1;
}
static char *__bpf_program__pin_name(struct bpf_program *prog)
{
char *name, *p;
name = p = strdup(prog->sec_name);
while ((p = strchr(p, '/')))
*p = '_';
return name;
}
static bool insn_is_subprog_call(const struct bpf_insn *insn)
{
return BPF_CLASS(insn->code) == BPF_JMP &&
BPF_OP(insn->code) == BPF_CALL &&
BPF_SRC(insn->code) == BPF_K &&
insn->src_reg == BPF_PSEUDO_CALL &&
insn->dst_reg == 0 &&
insn->off == 0;
}
static int
bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog,
const char *name, size_t sec_idx, const char *sec_name,
size_t sec_off, void *insn_data, size_t insn_data_sz)
{
if (insn_data_sz == 0 || insn_data_sz % BPF_INSN_SZ || sec_off % BPF_INSN_SZ) {
pr_warn("sec '%s': corrupted program '%s', offset %zu, size %zu\n",
sec_name, name, sec_off, insn_data_sz);
return -EINVAL;
}
memset(prog, 0, sizeof(*prog));
prog->obj = obj;
prog->sec_idx = sec_idx;
prog->sec_insn_off = sec_off / BPF_INSN_SZ;
prog->sec_insn_cnt = insn_data_sz / BPF_INSN_SZ;
/* insns_cnt can later be increased by appending used subprograms */
prog->insns_cnt = prog->sec_insn_cnt;
prog->type = BPF_PROG_TYPE_UNSPEC;
prog->load = true;
prog->instances.fds = NULL;
prog->instances.nr = -1;
prog->sec_name = strdup(sec_name);
if (!prog->sec_name)
goto errout;
prog->name = strdup(name);
if (!prog->name)
goto errout;
prog->pin_name = __bpf_program__pin_name(prog);
if (!prog->pin_name)
goto errout;
prog->insns = malloc(insn_data_sz);
if (!prog->insns)
goto errout;
memcpy(prog->insns, insn_data, insn_data_sz);
return 0;
errout:
pr_warn("sec '%s': failed to allocate memory for prog '%s'\n", sec_name, name);
bpf_program__exit(prog);
return -ENOMEM;
}
static int
bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data,
const char *sec_name, int sec_idx)
{
struct bpf_program *prog, *progs;
void *data = sec_data->d_buf;
size_t sec_sz = sec_data->d_size, sec_off, prog_sz;
int nr_progs, err;
const char *name;
GElf_Sym sym;
progs = obj->programs;
nr_progs = obj->nr_programs;
sec_off = 0;
while (sec_off < sec_sz) {
if (elf_sym_by_sec_off(obj, sec_idx, sec_off, STT_FUNC, &sym)) {
pr_warn("sec '%s': failed to find program symbol at offset %zu\n",
sec_name, sec_off);
return -LIBBPF_ERRNO__FORMAT;
}
prog_sz = sym.st_size;
name = elf_sym_str(obj, sym.st_name);
if (!name) {
pr_warn("sec '%s': failed to get symbol name for offset %zu\n",
sec_name, sec_off);
return -LIBBPF_ERRNO__FORMAT;
}
if (sec_off + prog_sz > sec_sz) {
pr_warn("sec '%s': program at offset %zu crosses section boundary\n",
sec_name, sec_off);
return -LIBBPF_ERRNO__FORMAT;
}
pr_debug("sec '%s': found program '%s' at insn offset %zu (%zu bytes), code size %zu insns (%zu bytes)\n",
sec_name, name, sec_off / BPF_INSN_SZ, sec_off, prog_sz / BPF_INSN_SZ, prog_sz);
progs = libbpf_reallocarray(progs, nr_progs + 1, sizeof(*progs));
if (!progs) {
/*
* In this case the original obj->programs
* is still valid, so don't need special treat for
* bpf_close_object().
*/
pr_warn("sec '%s': failed to alloc memory for new program '%s'\n",
sec_name, name);
return -ENOMEM;
}
obj->programs = progs;
prog = &progs[nr_progs];
err = bpf_object__init_prog(obj, prog, name, sec_idx, sec_name,
sec_off, data + sec_off, prog_sz);
if (err)
return err;
nr_progs++;
obj->nr_programs = nr_progs;
sec_off += prog_sz;
}
return 0;
}
static __u32 get_kernel_version(void)
{
__u32 major, minor, patch;
struct utsname info;
uname(&info);
if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
return 0;
return KERNEL_VERSION(major, minor, patch);
}
static const struct btf_member *
find_member_by_offset(const struct btf_type *t, __u32 bit_offset)
{
struct btf_member *m;
int i;
for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
if (btf_member_bit_offset(t, i) == bit_offset)
return m;
}
return NULL;
}
static const struct btf_member *
find_member_by_name(const struct btf *btf, const struct btf_type *t,
const char *name)
{
struct btf_member *m;
int i;
for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
if (!strcmp(btf__name_by_offset(btf, m->name_off), name))
return m;
}
return NULL;
}
#define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_"
static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
const char *name, __u32 kind);
static int
find_struct_ops_kern_types(const struct btf *btf, const char *tname,
const struct btf_type **type, __u32 *type_id,
const struct btf_type **vtype, __u32 *vtype_id,
const struct btf_member **data_member)
{
const struct btf_type *kern_type, *kern_vtype;
const struct btf_member *kern_data_member;
__s32 kern_vtype_id, kern_type_id;
__u32 i;
kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT);
if (kern_type_id < 0) {
pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n",
tname);
return kern_type_id;
}
kern_type = btf__type_by_id(btf, kern_type_id);
/* Find the corresponding "map_value" type that will be used
* in map_update(BPF_MAP_TYPE_STRUCT_OPS). For example,
* find "struct bpf_struct_ops_tcp_congestion_ops" from the
* btf_vmlinux.
*/
kern_vtype_id = find_btf_by_prefix_kind(btf, STRUCT_OPS_VALUE_PREFIX,
tname, BTF_KIND_STRUCT);
if (kern_vtype_id < 0) {
pr_warn("struct_ops init_kern: struct %s%s is not found in kernel BTF\n",
STRUCT_OPS_VALUE_PREFIX, tname);
return kern_vtype_id;
}
kern_vtype = btf__type_by_id(btf, kern_vtype_id);
/* Find "struct tcp_congestion_ops" from
* struct bpf_struct_ops_tcp_congestion_ops {
* [ ... ]
* struct tcp_congestion_ops data;
* }
*/
kern_data_member = btf_members(kern_vtype);
for (i = 0; i < btf_vlen(kern_vtype); i++, kern_data_member++) {
if (kern_data_member->type == kern_type_id)
break;
}
if (i == btf_vlen(kern_vtype)) {
pr_warn("struct_ops init_kern: struct %s data is not found in struct %s%s\n",
tname, STRUCT_OPS_VALUE_PREFIX, tname);
return -EINVAL;
}
*type = kern_type;
*type_id = kern_type_id;
*vtype = kern_vtype;
*vtype_id = kern_vtype_id;
*data_member = kern_data_member;
return 0;
}
static bool bpf_map__is_struct_ops(const struct bpf_map *map)
{
return map->def.type == BPF_MAP_TYPE_STRUCT_OPS;
}
/* Init the map's fields that depend on kern_btf */
static int bpf_map__init_kern_struct_ops(struct bpf_map *map,
const struct btf *btf,
const struct btf *kern_btf)
{
const struct btf_member *member, *kern_member, *kern_data_member;
const struct btf_type *type, *kern_type, *kern_vtype;
__u32 i, kern_type_id, kern_vtype_id, kern_data_off;
struct bpf_struct_ops *st_ops;
void *data, *kern_data;
const char *tname;
int err;
st_ops = map->st_ops;
type = st_ops->type;
tname = st_ops->tname;
err = find_struct_ops_kern_types(kern_btf, tname,
&kern_type, &kern_type_id,
&kern_vtype, &kern_vtype_id,
&kern_data_member);
if (err)
return err;
pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n",
map->name, st_ops->type_id, kern_type_id, kern_vtype_id);
map->def.value_size = kern_vtype->size;
map->btf_vmlinux_value_type_id = kern_vtype_id;
st_ops->kern_vdata = calloc(1, kern_vtype->size);
if (!st_ops->kern_vdata)
return -ENOMEM;
data = st_ops->data;
kern_data_off = kern_data_member->offset / 8;
kern_data = st_ops->kern_vdata + kern_data_off;
member = btf_members(type);
for (i = 0; i < btf_vlen(type); i++, member++) {
const struct btf_type *mtype, *kern_mtype;
__u32 mtype_id, kern_mtype_id;
void *mdata, *kern_mdata;
__s64 msize, kern_msize;
__u32 moff, kern_moff;
__u32 kern_member_idx;
const char *mname;
mname = btf__name_by_offset(btf, member->name_off);
kern_member = find_member_by_name(kern_btf, kern_type, mname);
if (!kern_member) {
pr_warn("struct_ops init_kern %s: Cannot find member %s in kernel BTF\n",
map->name, mname);
return -ENOTSUP;
}
kern_member_idx = kern_member - btf_members(kern_type);
if (btf_member_bitfield_size(type, i) ||
btf_member_bitfield_size(kern_type, kern_member_idx)) {
pr_warn("struct_ops init_kern %s: bitfield %s is not supported\n",
map->name, mname);
return -ENOTSUP;
}
moff = member->offset / 8;
kern_moff = kern_member->offset / 8;
mdata = data + moff;
kern_mdata = kern_data + kern_moff;
mtype = skip_mods_and_typedefs(btf, member->type, &mtype_id);
kern_mtype = skip_mods_and_typedefs(kern_btf, kern_member->type,
&kern_mtype_id);
if (BTF_INFO_KIND(mtype->info) !=
BTF_INFO_KIND(kern_mtype->info)) {
pr_warn("struct_ops init_kern %s: Unmatched member type %s %u != %u(kernel)\n",
map->name, mname, BTF_INFO_KIND(mtype->info),
BTF_INFO_KIND(kern_mtype->info));
return -ENOTSUP;
}
if (btf_is_ptr(mtype)) {
struct bpf_program *prog;
prog = st_ops->progs[i];
if (!prog)
continue;
kern_mtype = skip_mods_and_typedefs(kern_btf,
kern_mtype->type,
&kern_mtype_id);
/* mtype->type must be a func_proto which was
* guaranteed in bpf_object__collect_st_ops_relos(),
* so only check kern_mtype for func_proto here.
*/
if (!btf_is_func_proto(kern_mtype)) {
pr_warn("struct_ops init_kern %s: kernel member %s is not a func ptr\n",
map->name, mname);
return -ENOTSUP;
}
prog->attach_btf_id = kern_type_id;
prog->expected_attach_type = kern_member_idx;
st_ops->kern_func_off[i] = kern_data_off + kern_moff;
pr_debug("struct_ops init_kern %s: func ptr %s is set to prog %s from data(+%u) to kern_data(+%u)\n",
map->name, mname, prog->name, moff,
kern_moff);
continue;
}
msize = btf__resolve_size(btf, mtype_id);
kern_msize = btf__resolve_size(kern_btf, kern_mtype_id);
if (msize < 0 || kern_msize < 0 || msize != kern_msize) {
pr_warn("struct_ops init_kern %s: Error in size of member %s: %zd != %zd(kernel)\n",
map->name, mname, (ssize_t)msize,
(ssize_t)kern_msize);
return -ENOTSUP;
}
pr_debug("struct_ops init_kern %s: copy %s %u bytes from data(+%u) to kern_data(+%u)\n",
map->name, mname, (unsigned int)msize,
moff, kern_moff);
memcpy(kern_mdata, mdata, msize);
}
return 0;
}
static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj)
{
struct bpf_map *map;
size_t i;
int err;
for (i = 0; i < obj->nr_maps; i++) {
map = &obj->maps[i];
if (!bpf_map__is_struct_ops(map))
continue;
err = bpf_map__init_kern_struct_ops(map, obj->btf,
obj->btf_vmlinux);
if (err)
return err;
}
return 0;
}
static int bpf_object__init_struct_ops_maps(struct bpf_object *obj)
{
const struct btf_type *type, *datasec;
const struct btf_var_secinfo *vsi;
struct bpf_struct_ops *st_ops;
const char *tname, *var_name;
__s32 type_id, datasec_id;
const struct btf *btf;
struct bpf_map *map;
__u32 i;
if (obj->efile.st_ops_shndx == -1)
return 0;
btf = obj->btf;
datasec_id = btf__find_by_name_kind(btf, STRUCT_OPS_SEC,
BTF_KIND_DATASEC);
if (datasec_id < 0) {
pr_warn("struct_ops init: DATASEC %s not found\n",
STRUCT_OPS_SEC);
return -EINVAL;
}
datasec = btf__type_by_id(btf, datasec_id);
vsi = btf_var_secinfos(datasec);
for (i = 0; i < btf_vlen(datasec); i++, vsi++) {
type = btf__type_by_id(obj->btf, vsi->type);
var_name = btf__name_by_offset(obj->btf, type->name_off);
type_id = btf__resolve_type(obj->btf, vsi->type);
if (type_id < 0) {
pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n",
vsi->type, STRUCT_OPS_SEC);
return -EINVAL;
}
type = btf__type_by_id(obj->btf, type_id);
tname = btf__name_by_offset(obj->btf, type->name_off);
if (!tname[0]) {
pr_warn("struct_ops init: anonymous type is not supported\n");
return -ENOTSUP;
}
if (!btf_is_struct(type)) {
pr_warn("struct_ops init: %s is not a struct\n", tname);
return -EINVAL;
}
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map->sec_idx = obj->efile.st_ops_shndx;
map->sec_offset = vsi->offset;
map->name = strdup(var_name);
if (!map->name)
return -ENOMEM;
map->def.type = BPF_MAP_TYPE_STRUCT_OPS;
map->def.key_size = sizeof(int);
map->def.value_size = type->size;
map->def.max_entries = 1;
map->st_ops = calloc(1, sizeof(*map->st_ops));
if (!map->st_ops)
return -ENOMEM;
st_ops = map->st_ops;
st_ops->data = malloc(type->size);
st_ops->progs = calloc(btf_vlen(type), sizeof(*st_ops->progs));
st_ops->kern_func_off = malloc(btf_vlen(type) *
sizeof(*st_ops->kern_func_off));
if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off)
return -ENOMEM;
if (vsi->offset + type->size > obj->efile.st_ops_data->d_size) {
pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n",
var_name, STRUCT_OPS_SEC);
return -EINVAL;
}
memcpy(st_ops->data,
obj->efile.st_ops_data->d_buf + vsi->offset,
type->size);
st_ops->tname = tname;
st_ops->type = type;
st_ops->type_id = type_id;
pr_debug("struct_ops init: struct %s(type_id=%u) %s found at offset %u\n",
tname, type_id, var_name, vsi->offset);
}
return 0;
}
static struct bpf_object *bpf_object__new(const char *path,
const void *obj_buf,
size_t obj_buf_sz,
const char *obj_name)
{
struct bpf_object *obj;
char *end;
obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
if (!obj) {
pr_warn("alloc memory failed for %s\n", path);
return ERR_PTR(-ENOMEM);
}
strcpy(obj->path, path);
if (obj_name) {
strncpy(obj->name, obj_name, sizeof(obj->name) - 1);
obj->name[sizeof(obj->name) - 1] = 0;
} else {
/* Using basename() GNU version which doesn't modify arg. */
strncpy(obj->name, basename((void *)path),
sizeof(obj->name) - 1);
end = strchr(obj->name, '.');
if (end)
*end = 0;
}
obj->efile.fd = -1;
/*
* Caller of this function should also call
* bpf_object__elf_finish() after data collection to return
* obj_buf to user. If not, we should duplicate the buffer to
* avoid user freeing them before elf finish.
*/
obj->efile.obj_buf = obj_buf;
obj->efile.obj_buf_sz = obj_buf_sz;
obj->efile.maps_shndx = -1;
obj->efile.btf_maps_shndx = -1;
obj->efile.data_shndx = -1;
obj->efile.rodata_shndx = -1;
obj->efile.bss_shndx = -1;
obj->efile.st_ops_shndx = -1;
obj->kconfig_map_idx = -1;
obj->rodata_map_idx = -1;
obj->kern_version = get_kernel_version();
obj->loaded = false;
INIT_LIST_HEAD(&obj->list);
list_add(&obj->list, &bpf_objects_list);
return obj;
}
static void bpf_object__elf_finish(struct bpf_object *obj)
{
if (!obj_elf_valid(obj))
return;
if (obj->efile.elf) {
elf_end(obj->efile.elf);
obj->efile.elf = NULL;
}
obj->efile.symbols = NULL;
obj->efile.data = NULL;
obj->efile.rodata = NULL;
obj->efile.bss = NULL;
obj->efile.st_ops_data = NULL;
zfree(&obj->efile.reloc_sects);
obj->efile.nr_reloc_sects = 0;
zclose(obj->efile.fd);
obj->efile.obj_buf = NULL;
obj->efile.obj_buf_sz = 0;
}
/* if libelf is old and doesn't support mmap(), fall back to read() */
#ifndef ELF_C_READ_MMAP
#define ELF_C_READ_MMAP ELF_C_READ
#endif
static int bpf_object__elf_init(struct bpf_object *obj)
{
int err = 0;
GElf_Ehdr *ep;
if (obj_elf_valid(obj)) {
pr_warn("elf: init internal error\n");
return -LIBBPF_ERRNO__LIBELF;
}
if (obj->efile.obj_buf_sz > 0) {
/*
* obj_buf should have been validated by
* bpf_object__open_buffer().
*/
obj->efile.elf = elf_memory((char *)obj->efile.obj_buf,
obj->efile.obj_buf_sz);
} else {
obj->efile.fd = open(obj->path, O_RDONLY);
if (obj->efile.fd < 0) {
char errmsg[STRERR_BUFSIZE], *cp;
err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("elf: failed to open %s: %s\n", obj->path, cp);
return err;
}
obj->efile.elf = elf_begin(obj->efile.fd, ELF_C_READ_MMAP, NULL);
}
if (!obj->efile.elf) {
pr_warn("elf: failed to open %s as ELF file: %s\n", obj->path, elf_errmsg(-1));
err = -LIBBPF_ERRNO__LIBELF;
goto errout;
}
if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
pr_warn("elf: failed to get ELF header from %s: %s\n", obj->path, elf_errmsg(-1));
err = -LIBBPF_ERRNO__FORMAT;
goto errout;
}
ep = &obj->efile.ehdr;
if (elf_getshdrstrndx(obj->efile.elf, &obj->efile.shstrndx)) {
pr_warn("elf: failed to get section names section index for %s: %s\n",
obj->path, elf_errmsg(-1));
err = -LIBBPF_ERRNO__FORMAT;
goto errout;
}
/* Elf is corrupted/truncated, avoid calling elf_strptr. */
if (!elf_rawdata(elf_getscn(obj->efile.elf, obj->efile.shstrndx), NULL)) {
pr_warn("elf: failed to get section names strings from %s: %s\n",
obj->path, elf_errmsg(-1));
err = -LIBBPF_ERRNO__FORMAT;
goto errout;
}
/* Old LLVM set e_machine to EM_NONE */
if (ep->e_type != ET_REL ||
(ep->e_machine && ep->e_machine != EM_BPF)) {
pr_warn("elf: %s is not a valid eBPF object file\n", obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto errout;
}
return 0;
errout:
bpf_object__elf_finish(obj);
return err;
}
static int bpf_object__check_endianness(struct bpf_object *obj)
{
#if __BYTE_ORDER == __LITTLE_ENDIAN
if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
return 0;
#elif __BYTE_ORDER == __BIG_ENDIAN
if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
return 0;
#else
# error "Unrecognized __BYTE_ORDER__"
#endif
pr_warn("elf: endianness mismatch in %s.\n", obj->path);
return -LIBBPF_ERRNO__ENDIAN;
}
static int
bpf_object__init_license(struct bpf_object *obj, void *data, size_t size)
{
memcpy(obj->license, data, min(size, sizeof(obj->license) - 1));
pr_debug("license of %s is %s\n", obj->path, obj->license);
return 0;
}
static int
bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size)
{
__u32 kver;
if (size != sizeof(kver)) {
pr_warn("invalid kver section in %s\n", obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
memcpy(&kver, data, sizeof(kver));
obj->kern_version = kver;
pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version);
return 0;
}
static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
{
if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
type == BPF_MAP_TYPE_HASH_OF_MAPS)
return true;
return false;
}
int bpf_object__section_size(const struct bpf_object *obj, const char *name,
__u32 *size)
{
int ret = -ENOENT;
*size = 0;
if (!name) {
return -EINVAL;
} else if (!strcmp(name, DATA_SEC)) {
if (obj->efile.data)
*size = obj->efile.data->d_size;
} else if (!strcmp(name, BSS_SEC)) {
if (obj->efile.bss)
*size = obj->efile.bss->d_size;
} else if (!strcmp(name, RODATA_SEC)) {
if (obj->efile.rodata)
*size = obj->efile.rodata->d_size;
} else if (!strcmp(name, STRUCT_OPS_SEC)) {
if (obj->efile.st_ops_data)
*size = obj->efile.st_ops_data->d_size;
} else {
Elf_Scn *scn = elf_sec_by_name(obj, name);
Elf_Data *data = elf_sec_data(obj, scn);
if (data) {
ret = 0; /* found it */
*size = data->d_size;
}
}
return *size ? 0 : ret;
}
int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
__u32 *off)
{
Elf_Data *symbols = obj->efile.symbols;
const char *sname;
size_t si;
if (!name || !off)
return -EINVAL;
for (si = 0; si < symbols->d_size / sizeof(GElf_Sym); si++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, si, &sym))
continue;
if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
GELF_ST_TYPE(sym.st_info) != STT_OBJECT)
continue;
sname = elf_sym_str(obj, sym.st_name);
if (!sname) {
pr_warn("failed to get sym name string for var %s\n",
name);
return -EIO;
}
if (strcmp(name, sname) == 0) {
*off = sym.st_value;
return 0;
}
}
return -ENOENT;
}
static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
{
struct bpf_map *new_maps;
size_t new_cap;
int i;
if (obj->nr_maps < obj->maps_cap)
return &obj->maps[obj->nr_maps++];
new_cap = max((size_t)4, obj->maps_cap * 3 / 2);
new_maps = libbpf_reallocarray(obj->maps, new_cap, sizeof(*obj->maps));
if (!new_maps) {
pr_warn("alloc maps for object failed\n");
return ERR_PTR(-ENOMEM);
}
obj->maps_cap = new_cap;
obj->maps = new_maps;
/* zero out new maps */
memset(obj->maps + obj->nr_maps, 0,
(obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps));
/*
* fill all fd with -1 so won't close incorrect fd (fd=0 is stdin)
* when failure (zclose won't close negative fd)).
*/
for (i = obj->nr_maps; i < obj->maps_cap; i++) {
obj->maps[i].fd = -1;
obj->maps[i].inner_map_fd = -1;
}
return &obj->maps[obj->nr_maps++];
}
static size_t bpf_map_mmap_sz(const struct bpf_map *map)
{
long page_sz = sysconf(_SC_PAGE_SIZE);
size_t map_sz;
map_sz = (size_t)roundup(map->def.value_size, 8) * map->def.max_entries;
map_sz = roundup(map_sz, page_sz);
return map_sz;
}
static char *internal_map_name(struct bpf_object *obj,
enum libbpf_map_type type)
{
char map_name[BPF_OBJ_NAME_LEN], *p;
const char *sfx = libbpf_type_to_btf_name[type];
int sfx_len = max((size_t)7, strlen(sfx));
int pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1,
strlen(obj->name));
snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name,
sfx_len, libbpf_type_to_btf_name[type]);
/* sanitise map name to characters allowed by kernel */
for (p = map_name; *p && p < map_name + sizeof(map_name); p++)
if (!isalnum(*p) && *p != '_' && *p != '.')
*p = '_';
return strdup(map_name);
}
static int
bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
int sec_idx, void *data, size_t data_sz)
{
struct bpf_map_def *def;
struct bpf_map *map;
int err;
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map->libbpf_type = type;
map->sec_idx = sec_idx;
map->sec_offset = 0;
map->name = internal_map_name(obj, type);
if (!map->name) {
pr_warn("failed to alloc map name\n");
return -ENOMEM;
}
def = &map->def;
def->type = BPF_MAP_TYPE_ARRAY;
def->key_size = sizeof(int);
def->value_size = data_sz;
def->max_entries = 1;
def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_KCONFIG
? BPF_F_RDONLY_PROG : 0;
def->map_flags |= BPF_F_MMAPABLE;
pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n",
map->name, map->sec_idx, map->sec_offset, def->map_flags);
map->mmaped = mmap(NULL, bpf_map_mmap_sz(map), PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS, -1, 0);
if (map->mmaped == MAP_FAILED) {
err = -errno;
map->mmaped = NULL;
pr_warn("failed to alloc map '%s' content buffer: %d\n",
map->name, err);
zfree(&map->name);
return err;
}
if (data)
memcpy(map->mmaped, data, data_sz);
pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name);
return 0;
}
static int bpf_object__init_global_data_maps(struct bpf_object *obj)
{
int err;
/*
* Populate obj->maps with libbpf internal maps.
*/
if (obj->efile.data_shndx >= 0) {
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
obj->efile.data_shndx,
obj->efile.data->d_buf,
obj->efile.data->d_size);
if (err)
return err;
}
if (obj->efile.rodata_shndx >= 0) {
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
obj->efile.rodata_shndx,
obj->efile.rodata->d_buf,
obj->efile.rodata->d_size);
if (err)
return err;
obj->rodata_map_idx = obj->nr_maps - 1;
}
if (obj->efile.bss_shndx >= 0) {
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
obj->efile.bss_shndx,
NULL,
obj->efile.bss->d_size);
if (err)
return err;
}
return 0;
}
static struct extern_desc *find_extern_by_name(const struct bpf_object *obj,
const void *name)
{
int i;
for (i = 0; i < obj->nr_extern; i++) {
if (strcmp(obj->externs[i].name, name) == 0)
return &obj->externs[i];
}
return NULL;
}
static int set_kcfg_value_tri(struct extern_desc *ext, void *ext_val,
char value)
{
switch (ext->kcfg.type) {
case KCFG_BOOL:
if (value == 'm') {
pr_warn("extern (kcfg) %s=%c should be tristate or char\n",
ext->name, value);
return -EINVAL;
}
*(bool *)ext_val = value == 'y' ? true : false;
break;
case KCFG_TRISTATE:
if (value == 'y')
*(enum libbpf_tristate *)ext_val = TRI_YES;
else if (value == 'm')
*(enum libbpf_tristate *)ext_val = TRI_MODULE;
else /* value == 'n' */
*(enum libbpf_tristate *)ext_val = TRI_NO;
break;
case KCFG_CHAR:
*(char *)ext_val = value;
break;
case KCFG_UNKNOWN:
case KCFG_INT:
case KCFG_CHAR_ARR:
default:
pr_warn("extern (kcfg) %s=%c should be bool, tristate, or char\n",
ext->name, value);
return -EINVAL;
}
ext->is_set = true;
return 0;
}
static int set_kcfg_value_str(struct extern_desc *ext, char *ext_val,
const char *value)
{
size_t len;
if (ext->kcfg.type != KCFG_CHAR_ARR) {
pr_warn("extern (kcfg) %s=%s should be char array\n", ext->name, value);
return -EINVAL;
}
len = strlen(value);
if (value[len - 1] != '"') {
pr_warn("extern (kcfg) '%s': invalid string config '%s'\n",
ext->name, value);
return -EINVAL;
}
/* strip quotes */
len -= 2;
if (len >= ext->kcfg.sz) {
pr_warn("extern (kcfg) '%s': long string config %s of (%zu bytes) truncated to %d bytes\n",
ext->name, value, len, ext->kcfg.sz - 1);
len = ext->kcfg.sz - 1;
}
memcpy(ext_val, value + 1, len);
ext_val[len] = '\0';
ext->is_set = true;
return 0;
}
static int parse_u64(const char *value, __u64 *res)
{
char *value_end;
int err;
errno = 0;
*res = strtoull(value, &value_end, 0);
if (errno) {
err = -errno;
pr_warn("failed to parse '%s' as integer: %d\n", value, err);
return err;
}
if (*value_end) {
pr_warn("failed to parse '%s' as integer completely\n", value);
return -EINVAL;
}
return 0;
}
static bool is_kcfg_value_in_range(const struct extern_desc *ext, __u64 v)
{
int bit_sz = ext->kcfg.sz * 8;
if (ext->kcfg.sz == 8)
return true;
/* Validate that value stored in u64 fits in integer of `ext->sz`
* bytes size without any loss of information. If the target integer
* is signed, we rely on the following limits of integer type of
* Y bits and subsequent transformation:
*
* -2^(Y-1) <= X <= 2^(Y-1) - 1
* 0 <= X + 2^(Y-1) <= 2^Y - 1
* 0 <= X + 2^(Y-1) < 2^Y
*
* For unsigned target integer, check that all the (64 - Y) bits are
* zero.
*/
if (ext->kcfg.is_signed)
return v + (1ULL << (bit_sz - 1)) < (1ULL << bit_sz);
else
return (v >> bit_sz) == 0;
}
static int set_kcfg_value_num(struct extern_desc *ext, void *ext_val,
__u64 value)
{
if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR) {
pr_warn("extern (kcfg) %s=%llu should be integer\n",
ext->name, (unsigned long long)value);
return -EINVAL;
}
if (!is_kcfg_value_in_range(ext, value)) {
pr_warn("extern (kcfg) %s=%llu value doesn't fit in %d bytes\n",
ext->name, (unsigned long long)value, ext->kcfg.sz);
return -ERANGE;
}
switch (ext->kcfg.sz) {
case 1: *(__u8 *)ext_val = value; break;
case 2: *(__u16 *)ext_val = value; break;
case 4: *(__u32 *)ext_val = value; break;
case 8: *(__u64 *)ext_val = value; break;
default:
return -EINVAL;
}
ext->is_set = true;
return 0;
}
static int bpf_object__process_kconfig_line(struct bpf_object *obj,
char *buf, void *data)
{
struct extern_desc *ext;
char *sep, *value;
int len, err = 0;
void *ext_val;
__u64 num;
if (strncmp(buf, "CONFIG_", 7))
return 0;
sep = strchr(buf, '=');
if (!sep) {
pr_warn("failed to parse '%s': no separator\n", buf);
return -EINVAL;
}
/* Trim ending '\n' */
len = strlen(buf);
if (buf[len - 1] == '\n')
buf[len - 1] = '\0';
/* Split on '=' and ensure that a value is present. */
*sep = '\0';
if (!sep[1]) {
*sep = '=';
pr_warn("failed to parse '%s': no value\n", buf);
return -EINVAL;
}
ext = find_extern_by_name(obj, buf);
if (!ext || ext->is_set)
return 0;
ext_val = data + ext->kcfg.data_off;
value = sep + 1;
switch (*value) {
case 'y': case 'n': case 'm':
err = set_kcfg_value_tri(ext, ext_val, *value);
break;
case '"':
err = set_kcfg_value_str(ext, ext_val, value);
break;
default:
/* assume integer */
err = parse_u64(value, &num);
if (err) {
pr_warn("extern (kcfg) %s=%s should be integer\n",
ext->name, value);
return err;
}
err = set_kcfg_value_num(ext, ext_val, num);
break;
}
if (err)
return err;
pr_debug("extern (kcfg) %s=%s\n", ext->name, value);
return 0;
}
static int bpf_object__read_kconfig_file(struct bpf_object *obj, void *data)
{
char buf[PATH_MAX];
struct utsname uts;
int len, err = 0;
gzFile file;
uname(&uts);
len = snprintf(buf, PATH_MAX, "/boot/config-%s", uts.release);
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
/* gzopen also accepts uncompressed files. */
file = gzopen(buf, "r");
if (!file)
file = gzopen("/proc/config.gz", "r");
if (!file) {
pr_warn("failed to open system Kconfig\n");
return -ENOENT;
}
while (gzgets(file, buf, sizeof(buf))) {
err = bpf_object__process_kconfig_line(obj, buf, data);
if (err) {
pr_warn("error parsing system Kconfig line '%s': %d\n",
buf, err);
goto out;
}
}
out:
gzclose(file);
return err;
}
static int bpf_object__read_kconfig_mem(struct bpf_object *obj,
const char *config, void *data)
{
char buf[PATH_MAX];
int err = 0;
FILE *file;
file = fmemopen((void *)config, strlen(config), "r");
if (!file) {
err = -errno;
pr_warn("failed to open in-memory Kconfig: %d\n", err);
return err;
}
while (fgets(buf, sizeof(buf), file)) {
err = bpf_object__process_kconfig_line(obj, buf, data);
if (err) {
pr_warn("error parsing in-memory Kconfig line '%s': %d\n",
buf, err);
break;
}
}
fclose(file);
return err;
}
static int bpf_object__init_kconfig_map(struct bpf_object *obj)
{
struct extern_desc *last_ext = NULL, *ext;
size_t map_sz;
int i, err;
for (i = 0; i < obj->nr_extern; i++) {
ext = &obj->externs[i];
if (ext->type == EXT_KCFG)
last_ext = ext;
}
if (!last_ext)
return 0;
map_sz = last_ext->kcfg.data_off + last_ext->kcfg.sz;
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_KCONFIG,
obj->efile.symbols_shndx,
NULL, map_sz);
if (err)
return err;
obj->kconfig_map_idx = obj->nr_maps - 1;
return 0;
}
static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
{
Elf_Data *symbols = obj->efile.symbols;
int i, map_def_sz = 0, nr_maps = 0, nr_syms;
Elf_Data *data = NULL;
Elf_Scn *scn;
if (obj->efile.maps_shndx < 0)
return 0;
if (!symbols)
return -EINVAL;
scn = elf_sec_by_idx(obj, obj->efile.maps_shndx);
data = elf_sec_data(obj, scn);
if (!scn || !data) {
pr_warn("elf: failed to get legacy map definitions for %s\n",
obj->path);
return -EINVAL;
}
/*
* Count number of maps. Each map has a name.
* Array of maps is not supported: only the first element is
* considered.
*
* TODO: Detect array of map and report error.
*/
nr_syms = symbols->d_size / sizeof(GElf_Sym);
for (i = 0; i < nr_syms; i++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, i, &sym))
continue;
if (sym.st_shndx != obj->efile.maps_shndx)
continue;
nr_maps++;
}
/* Assume equally sized map definitions */
pr_debug("elf: found %d legacy map definitions (%zd bytes) in %s\n",
nr_maps, data->d_size, obj->path);
if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) {
pr_warn("elf: unable to determine legacy map definition size in %s\n",
obj->path);
return -EINVAL;
}
map_def_sz = data->d_size / nr_maps;
/* Fill obj->maps using data in "maps" section. */
for (i = 0; i < nr_syms; i++) {
GElf_Sym sym;
const char *map_name;
struct bpf_map_def *def;
struct bpf_map *map;
if (!gelf_getsym(symbols, i, &sym))
continue;
if (sym.st_shndx != obj->efile.maps_shndx)
continue;
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map_name = elf_sym_str(obj, sym.st_name);
if (!map_name) {
pr_warn("failed to get map #%d name sym string for obj %s\n",
i, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
map->libbpf_type = LIBBPF_MAP_UNSPEC;
map->sec_idx = sym.st_shndx;
map->sec_offset = sym.st_value;
pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n",
map_name, map->sec_idx, map->sec_offset);
if (sym.st_value + map_def_sz > data->d_size) {
pr_warn("corrupted maps section in %s: last map \"%s\" too small\n",
obj->path, map_name);
return -EINVAL;
}
map->name = strdup(map_name);
if (!map->name) {
pr_warn("failed to alloc map name\n");
return -ENOMEM;
}
pr_debug("map %d is \"%s\"\n", i, map->name);
def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
/*
* If the definition of the map in the object file fits in
* bpf_map_def, copy it. Any extra fields in our version
* of bpf_map_def will default to zero as a result of the
* calloc above.
*/
if (map_def_sz <= sizeof(struct bpf_map_def)) {
memcpy(&map->def, def, map_def_sz);
} else {
/*
* Here the map structure being read is bigger than what
* we expect, truncate if the excess bits are all zero.
* If they are not zero, reject this map as
* incompatible.
*/
char *b;
for (b = ((char *)def) + sizeof(struct bpf_map_def);
b < ((char *)def) + map_def_sz; b++) {
if (*b != 0) {
pr_warn("maps section in %s: \"%s\" has unrecognized, non-zero options\n",
obj->path, map_name);
if (strict)
return -EINVAL;
}
}
memcpy(&map->def, def, sizeof(struct bpf_map_def));
}
}
return 0;
}
static const struct btf_type *
skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
{
const struct btf_type *t = btf__type_by_id(btf, id);
if (res_id)
*res_id = id;
while (btf_is_mod(t) || btf_is_typedef(t)) {
if (res_id)
*res_id = t->type;
t = btf__type_by_id(btf, t->type);
}
return t;
}
static const struct btf_type *
resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
{
const struct btf_type *t;
t = skip_mods_and_typedefs(btf, id, NULL);
if (!btf_is_ptr(t))
return NULL;
t = skip_mods_and_typedefs(btf, t->type, res_id);
return btf_is_func_proto(t) ? t : NULL;
}
static const char *btf_kind_str(const struct btf_type *t)
{
switch (btf_kind(t)) {
case BTF_KIND_UNKN: return "void";
case BTF_KIND_INT: return "int";
case BTF_KIND_PTR: return "ptr";
case BTF_KIND_ARRAY: return "array";
case BTF_KIND_STRUCT: return "struct";
case BTF_KIND_UNION: return "union";
case BTF_KIND_ENUM: return "enum";
case BTF_KIND_FWD: return "fwd";
case BTF_KIND_TYPEDEF: return "typedef";
case BTF_KIND_VOLATILE: return "volatile";
case BTF_KIND_CONST: return "const";
case BTF_KIND_RESTRICT: return "restrict";
case BTF_KIND_FUNC: return "func";
case BTF_KIND_FUNC_PROTO: return "func_proto";
case BTF_KIND_VAR: return "var";
case BTF_KIND_DATASEC: return "datasec";
default: return "unknown";
}
}
/*
* Fetch integer attribute of BTF map definition. Such attributes are
* represented using a pointer to an array, in which dimensionality of array
* encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY];
* encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF
* type definition, while using only sizeof(void *) space in ELF data section.
*/
static bool get_map_field_int(const char *map_name, const struct btf *btf,
const struct btf_member *m, __u32 *res)
{
const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
const char *name = btf__name_by_offset(btf, m->name_off);
const struct btf_array *arr_info;
const struct btf_type *arr_t;
if (!btf_is_ptr(t)) {
pr_warn("map '%s': attr '%s': expected PTR, got %s.\n",
map_name, name, btf_kind_str(t));
return false;
}
arr_t = btf__type_by_id(btf, t->type);
if (!arr_t) {
pr_warn("map '%s': attr '%s': type [%u] not found.\n",
map_name, name, t->type);
return false;
}
if (!btf_is_array(arr_t)) {
pr_warn("map '%s': attr '%s': expected ARRAY, got %s.\n",
map_name, name, btf_kind_str(arr_t));
return false;
}
arr_info = btf_array(arr_t);
*res = arr_info->nelems;
return true;
}
static int build_map_pin_path(struct bpf_map *map, const char *path)
{
char buf[PATH_MAX];
int len;
if (!path)
path = "/sys/fs/bpf";
len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
return bpf_map__set_pin_path(map, buf);
}
static int parse_btf_map_def(struct bpf_object *obj,
struct bpf_map *map,
const struct btf_type *def,
bool strict, bool is_inner,
const char *pin_root_path)
{
const struct btf_type *t;
const struct btf_member *m;
int vlen, i;
vlen = btf_vlen(def);
m = btf_members(def);
for (i = 0; i < vlen; i++, m++) {
const char *name = btf__name_by_offset(obj->btf, m->name_off);
if (!name) {
pr_warn("map '%s': invalid field #%d.\n", map->name, i);
return -EINVAL;
}
if (strcmp(name, "type") == 0) {
if (!get_map_field_int(map->name, obj->btf, m,
&map->def.type))
return -EINVAL;
pr_debug("map '%s': found type = %u.\n",
map->name, map->def.type);
} else if (strcmp(name, "max_entries") == 0) {
if (!get_map_field_int(map->name, obj->btf, m,
&map->def.max_entries))
return -EINVAL;
pr_debug("map '%s': found max_entries = %u.\n",
map->name, map->def.max_entries);
} else if (strcmp(name, "map_flags") == 0) {
if (!get_map_field_int(map->name, obj->btf, m,
&map->def.map_flags))
return -EINVAL;
pr_debug("map '%s': found map_flags = %u.\n",
map->name, map->def.map_flags);
} else if (strcmp(name, "numa_node") == 0) {
if (!get_map_field_int(map->name, obj->btf, m, &map->numa_node))
return -EINVAL;
pr_debug("map '%s': found numa_node = %u.\n", map->name, map->numa_node);
} else if (strcmp(name, "key_size") == 0) {
__u32 sz;
if (!get_map_field_int(map->name, obj->btf, m, &sz))
return -EINVAL;
pr_debug("map '%s': found key_size = %u.\n",
map->name, sz);
if (map->def.key_size && map->def.key_size != sz) {
pr_warn("map '%s': conflicting key size %u != %u.\n",
map->name, map->def.key_size, sz);
return -EINVAL;
}
map->def.key_size = sz;
} else if (strcmp(name, "key") == 0) {
__s64 sz;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': key type [%d] not found.\n",
map->name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': key spec is not PTR: %s.\n",
map->name, btf_kind_str(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n",
map->name, t->type, (ssize_t)sz);
return sz;
}
pr_debug("map '%s': found key [%u], sz = %zd.\n",
map->name, t->type, (ssize_t)sz);
if (map->def.key_size && map->def.key_size != sz) {
pr_warn("map '%s': conflicting key size %u != %zd.\n",
map->name, map->def.key_size, (ssize_t)sz);
return -EINVAL;
}
map->def.key_size = sz;
map->btf_key_type_id = t->type;
} else if (strcmp(name, "value_size") == 0) {
__u32 sz;
if (!get_map_field_int(map->name, obj->btf, m, &sz))
return -EINVAL;
pr_debug("map '%s': found value_size = %u.\n",
map->name, sz);
if (map->def.value_size && map->def.value_size != sz) {
pr_warn("map '%s': conflicting value size %u != %u.\n",
map->name, map->def.value_size, sz);
return -EINVAL;
}
map->def.value_size = sz;
} else if (strcmp(name, "value") == 0) {
__s64 sz;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': value type [%d] not found.\n",
map->name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': value spec is not PTR: %s.\n",
map->name, btf_kind_str(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n",
map->name, t->type, (ssize_t)sz);
return sz;
}
pr_debug("map '%s': found value [%u], sz = %zd.\n",
map->name, t->type, (ssize_t)sz);
if (map->def.value_size && map->def.value_size != sz) {
pr_warn("map '%s': conflicting value size %u != %zd.\n",
map->name, map->def.value_size, (ssize_t)sz);
return -EINVAL;
}
map->def.value_size = sz;
map->btf_value_type_id = t->type;
}
else if (strcmp(name, "values") == 0) {
int err;
if (is_inner) {
pr_warn("map '%s': multi-level inner maps not supported.\n",
map->name);
return -ENOTSUP;
}
if (i != vlen - 1) {
pr_warn("map '%s': '%s' member should be last.\n",
map->name, name);
return -EINVAL;
}
if (!bpf_map_type__is_map_in_map(map->def.type)) {
pr_warn("map '%s': should be map-in-map.\n",
map->name);
return -ENOTSUP;
}
if (map->def.value_size && map->def.value_size != 4) {
pr_warn("map '%s': conflicting value size %u != 4.\n",
map->name, map->def.value_size);
return -EINVAL;
}
map->def.value_size = 4;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': map-in-map inner type [%d] not found.\n",
map->name, m->type);
return -EINVAL;
}
if (!btf_is_array(t) || btf_array(t)->nelems) {
pr_warn("map '%s': map-in-map inner spec is not a zero-sized array.\n",
map->name);
return -EINVAL;
}
t = skip_mods_and_typedefs(obj->btf, btf_array(t)->type,
NULL);
if (!btf_is_ptr(t)) {
pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n",
map->name, btf_kind_str(t));
return -EINVAL;
}
t = skip_mods_and_typedefs(obj->btf, t->type, NULL);
if (!btf_is_struct(t)) {
pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n",
map->name, btf_kind_str(t));
return -EINVAL;
}
map->inner_map = calloc(1, sizeof(*map->inner_map));
if (!map->inner_map)
return -ENOMEM;
map->inner_map->sec_idx = obj->efile.btf_maps_shndx;
map->inner_map->name = malloc(strlen(map->name) +
sizeof(".inner") + 1);
if (!map->inner_map->name)
return -ENOMEM;
sprintf(map->inner_map->name, "%s.inner", map->name);
err = parse_btf_map_def(obj, map->inner_map, t, strict,
true /* is_inner */, NULL);
if (err)
return err;
} else if (strcmp(name, "pinning") == 0) {
__u32 val;
int err;
if (is_inner) {
pr_debug("map '%s': inner def can't be pinned.\n",
map->name);
return -EINVAL;
}
if (!get_map_field_int(map->name, obj->btf, m, &val))
return -EINVAL;
pr_debug("map '%s': found pinning = %u.\n",
map->name, val);
if (val != LIBBPF_PIN_NONE &&
val != LIBBPF_PIN_BY_NAME) {
pr_warn("map '%s': invalid pinning value %u.\n",
map->name, val);
return -EINVAL;
}
if (val == LIBBPF_PIN_BY_NAME) {
err = build_map_pin_path(map, pin_root_path);
if (err) {
pr_warn("map '%s': couldn't build pin path.\n",
map->name);
return err;
}
}
} else {
if (strict) {
pr_warn("map '%s': unknown field '%s'.\n",
map->name, name);
return -ENOTSUP;
}
pr_debug("map '%s': ignoring unknown field '%s'.\n",
map->name, name);
}
}
if (map->def.type == BPF_MAP_TYPE_UNSPEC) {
pr_warn("map '%s': map type isn't specified.\n", map->name);
return -EINVAL;
}
return 0;
}
static int bpf_object__init_user_btf_map(struct bpf_object *obj,
const struct btf_type *sec,
int var_idx, int sec_idx,
const Elf_Data *data, bool strict,
const char *pin_root_path)
{
const struct btf_type *var, *def;
const struct btf_var_secinfo *vi;
const struct btf_var *var_extra;
const char *map_name;
struct bpf_map *map;
vi = btf_var_secinfos(sec) + var_idx;
var = btf__type_by_id(obj->btf, vi->type);
var_extra = btf_var(var);
map_name = btf__name_by_offset(obj->btf, var->name_off);
if (map_name == NULL || map_name[0] == '\0') {
pr_warn("map #%d: empty name.\n", var_idx);
return -EINVAL;
}
if ((__u64)vi->offset + vi->size > data->d_size) {
pr_warn("map '%s' BTF data is corrupted.\n", map_name);
return -EINVAL;
}
if (!btf_is_var(var)) {
pr_warn("map '%s': unexpected var kind %s.\n",
map_name, btf_kind_str(var));
return -EINVAL;
}
if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED &&
var_extra->linkage != BTF_VAR_STATIC) {
pr_warn("map '%s': unsupported var linkage %u.\n",
map_name, var_extra->linkage);
return -EOPNOTSUPP;
}
def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
if (!btf_is_struct(def)) {
pr_warn("map '%s': unexpected def kind %s.\n",
map_name, btf_kind_str(var));
return -EINVAL;
}
if (def->size > vi->size) {
pr_warn("map '%s': invalid def size.\n", map_name);
return -EINVAL;
}
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map->name = strdup(map_name);
if (!map->name) {
pr_warn("map '%s': failed to alloc map name.\n", map_name);
return -ENOMEM;
}
map->libbpf_type = LIBBPF_MAP_UNSPEC;
map->def.type = BPF_MAP_TYPE_UNSPEC;
map->sec_idx = sec_idx;
map->sec_offset = vi->offset;
map->btf_var_idx = var_idx;
pr_debug("map '%s': at sec_idx %d, offset %zu.\n",
map_name, map->sec_idx, map->sec_offset);
return parse_btf_map_def(obj, map, def, strict, false, pin_root_path);
}
static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
const char *pin_root_path)
{
const struct btf_type *sec = NULL;
int nr_types, i, vlen, err;
const struct btf_type *t;
const char *name;
Elf_Data *data;
Elf_Scn *scn;
if (obj->efile.btf_maps_shndx < 0)
return 0;
scn = elf_sec_by_idx(obj, obj->efile.btf_maps_shndx);
data = elf_sec_data(obj, scn);
if (!scn || !data) {
pr_warn("elf: failed to get %s map definitions for %s\n",
MAPS_ELF_SEC, obj->path);
return -EINVAL;
}
nr_types = btf__get_nr_types(obj->btf);
for (i = 1; i <= nr_types; i++) {
t = btf__type_by_id(obj->btf, i);
if (!btf_is_datasec(t))
continue;
name = btf__name_by_offset(obj->btf, t->name_off);
if (strcmp(name, MAPS_ELF_SEC) == 0) {
sec = t;
obj->efile.btf_maps_sec_btf_id = i;
break;
}
}
if (!sec) {
pr_warn("DATASEC '%s' not found.\n", MAPS_ELF_SEC);
return -ENOENT;
}
vlen = btf_vlen(sec);
for (i = 0; i < vlen; i++) {
err = bpf_object__init_user_btf_map(obj, sec, i,
obj->efile.btf_maps_shndx,
data, strict,
pin_root_path);
if (err)
return err;
}
return 0;
}
static int bpf_object__init_maps(struct bpf_object *obj,
const struct bpf_object_open_opts *opts)
{
const char *pin_root_path;
bool strict;
int err;
strict = !OPTS_GET(opts, relaxed_maps, false);
pin_root_path = OPTS_GET(opts, pin_root_path, NULL);
err = bpf_object__init_user_maps(obj, strict);
err = err ?: bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
err = err ?: bpf_object__init_global_data_maps(obj);
err = err ?: bpf_object__init_kconfig_map(obj);
err = err ?: bpf_object__init_struct_ops_maps(obj);
if (err)
return err;
return 0;
}
static bool section_have_execinstr(struct bpf_object *obj, int idx)
{
GElf_Shdr sh;
if (elf_sec_hdr(obj, elf_sec_by_idx(obj, idx), &sh))
return false;
return sh.sh_flags & SHF_EXECINSTR;
}
static bool btf_needs_sanitization(struct bpf_object *obj)
{
bool has_func_global = kernel_supports(FEAT_BTF_GLOBAL_FUNC);
bool has_datasec = kernel_supports(FEAT_BTF_DATASEC);
bool has_func = kernel_supports(FEAT_BTF_FUNC);
return !has_func || !has_datasec || !has_func_global;
}
static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf)
{
bool has_func_global = kernel_supports(FEAT_BTF_GLOBAL_FUNC);
bool has_datasec = kernel_supports(FEAT_BTF_DATASEC);
bool has_func = kernel_supports(FEAT_BTF_FUNC);
struct btf_type *t;
int i, j, vlen;
for (i = 1; i <= btf__get_nr_types(btf); i++) {
t = (struct btf_type *)btf__type_by_id(btf, i);
if (!has_datasec && btf_is_var(t)) {
/* replace VAR with INT */
t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
/*
* using size = 1 is the safest choice, 4 will be too
* big and cause kernel BTF validation failure if
* original variable took less than 4 bytes
*/
t->size = 1;
*(int *)(t + 1) = BTF_INT_ENC(0, 0, 8);
} else if (!has_datasec && btf_is_datasec(t)) {
/* replace DATASEC with STRUCT */
const struct btf_var_secinfo *v = btf_var_secinfos(t);
struct btf_member *m = btf_members(t);
struct btf_type *vt;
char *name;
name = (char *)btf__name_by_offset(btf, t->name_off);
while (*name) {
if (*name == '.')
*name = '_';
name++;
}
vlen = btf_vlen(t);
t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen);
for (j = 0; j < vlen; j++, v++, m++) {
/* order of field assignments is important */
m->offset = v->offset * 8;
m->type = v->type;
/* preserve variable name as member name */
vt = (void *)btf__type_by_id(btf, v->type);
m->name_off = vt->name_off;
}
} else if (!has_func && btf_is_func_proto(t)) {
/* replace FUNC_PROTO with ENUM */
vlen = btf_vlen(t);
t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen);
t->size = sizeof(__u32); /* kernel enforced */
} else if (!has_func && btf_is_func(t)) {
/* replace FUNC with TYPEDEF */
t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0);
} else if (!has_func_global && btf_is_func(t)) {
/* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */
t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0);
}
}
}
static bool libbpf_needs_btf(const struct bpf_object *obj)
{
return obj->efile.btf_maps_shndx >= 0 ||
obj->efile.st_ops_shndx >= 0 ||
obj->nr_extern > 0;
}
static bool kernel_needs_btf(const struct bpf_object *obj)
{
return obj->efile.st_ops_shndx >= 0;
}
static int bpf_object__init_btf(struct bpf_object *obj,
Elf_Data *btf_data,
Elf_Data *btf_ext_data)
{
int err = -ENOENT;
if (btf_data) {
obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
if (IS_ERR(obj->btf)) {
err = PTR_ERR(obj->btf);
obj->btf = NULL;
pr_warn("Error loading ELF section %s: %d.\n",
BTF_ELF_SEC, err);
goto out;
}
/* enforce 8-byte pointers for BPF-targeted BTFs */
btf__set_pointer_size(obj->btf, 8);
err = 0;
}
if (btf_ext_data) {
if (!obj->btf) {
pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
BTF_EXT_ELF_SEC, BTF_ELF_SEC);
goto out;
}
obj->btf_ext = btf_ext__new(btf_ext_data->d_buf,
btf_ext_data->d_size);
if (IS_ERR(obj->btf_ext)) {
pr_warn("Error loading ELF section %s: %ld. Ignored and continue.\n",
BTF_EXT_ELF_SEC, PTR_ERR(obj->btf_ext));
obj->btf_ext = NULL;
goto out;
}
}
out:
if (err && libbpf_needs_btf(obj)) {
pr_warn("BTF is required, but is missing or corrupted.\n");
return err;
}
return 0;
}
static int bpf_object__finalize_btf(struct bpf_object *obj)
{
int err;
if (!obj->btf)
return 0;
err = btf__finalize_data(obj, obj->btf);
if (err) {
pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err);
return err;
}
return 0;
}
static inline bool libbpf_prog_needs_vmlinux_btf(struct bpf_program *prog)
{
if (prog->type == BPF_PROG_TYPE_STRUCT_OPS ||
prog->type == BPF_PROG_TYPE_LSM)
return true;
/* BPF_PROG_TYPE_TRACING programs which do not attach to other programs
* also need vmlinux BTF
*/
if (prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd)
return true;
return false;
}
static int bpf_object__load_vmlinux_btf(struct bpf_object *obj)
{
bool need_vmlinux_btf = false;
struct bpf_program *prog;
int i, err;
/* CO-RE relocations need kernel BTF */
if (obj->btf_ext && obj->btf_ext->core_relo_info.len)
need_vmlinux_btf = true;
/* Support for typed ksyms needs kernel BTF */
for (i = 0; i < obj->nr_extern; i++) {
const struct extern_desc *ext;
ext = &obj->externs[i];
if (ext->type == EXT_KSYM && ext->ksym.type_id) {
need_vmlinux_btf = true;
break;
}
}
bpf_object__for_each_program(prog, obj) {
if (!prog->load)
continue;
if (libbpf_prog_needs_vmlinux_btf(prog)) {
need_vmlinux_btf = true;
break;
}
}
if (!need_vmlinux_btf)
return 0;
obj->btf_vmlinux = libbpf_find_kernel_btf();
if (IS_ERR(obj->btf_vmlinux)) {
err = PTR_ERR(obj->btf_vmlinux);
pr_warn("Error loading vmlinux BTF: %d\n", err);
obj->btf_vmlinux = NULL;
return err;
}
return 0;
}
static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
{
struct btf *kern_btf = obj->btf;
bool btf_mandatory, sanitize;
int err = 0;
if (!obj->btf)
return 0;
if (!kernel_supports(FEAT_BTF)) {
if (kernel_needs_btf(obj)) {
err = -EOPNOTSUPP;
goto report;
}
pr_debug("Kernel doesn't support BTF, skipping uploading it.\n");
return 0;
}
sanitize = btf_needs_sanitization(obj);
if (sanitize) {
const void *raw_data;
__u32 sz;
/* clone BTF to sanitize a copy and leave the original intact */
raw_data = btf__get_raw_data(obj->btf, &sz);
kern_btf = btf__new(raw_data, sz);
if (IS_ERR(kern_btf))
return PTR_ERR(kern_btf);
/* enforce 8-byte pointers for BPF-targeted BTFs */
btf__set_pointer_size(obj->btf, 8);
bpf_object__sanitize_btf(obj, kern_btf);
}
err = btf__load(kern_btf);
if (sanitize) {
if (!err) {
/* move fd to libbpf's BTF */
btf__set_fd(obj->btf, btf__fd(kern_btf));
btf__set_fd(kern_btf, -1);
}
btf__free(kern_btf);
}
report:
if (err) {
btf_mandatory = kernel_needs_btf(obj);
pr_warn("Error loading .BTF into kernel: %d. %s\n", err,
btf_mandatory ? "BTF is mandatory, can't proceed."
: "BTF is optional, ignoring.");
if (!btf_mandatory)
err = 0;
}
return err;
}
static const char *elf_sym_str(const struct bpf_object *obj, size_t off)
{
const char *name;
name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, off);
if (!name) {
pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n",
off, obj->path, elf_errmsg(-1));
return NULL;
}
return name;
}
static const char *elf_sec_str(const struct bpf_object *obj, size_t off)
{
const char *name;
name = elf_strptr(obj->efile.elf, obj->efile.shstrndx, off);
if (!name) {
pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n",
off, obj->path, elf_errmsg(-1));
return NULL;
}
return name;
}
static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx)
{
Elf_Scn *scn;
scn = elf_getscn(obj->efile.elf, idx);
if (!scn) {
pr_warn("elf: failed to get section(%zu) from %s: %s\n",
idx, obj->path, elf_errmsg(-1));
return NULL;
}
return scn;
}
static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name)
{
Elf_Scn *scn = NULL;
Elf *elf = obj->efile.elf;
const char *sec_name;
while ((scn = elf_nextscn(elf, scn)) != NULL) {
sec_name = elf_sec_name(obj, scn);
if (!sec_name)
return NULL;
if (strcmp(sec_name, name) != 0)
continue;
return scn;
}
return NULL;
}
static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr)
{
if (!scn)
return -EINVAL;
if (gelf_getshdr(scn, hdr) != hdr) {
pr_warn("elf: failed to get section(%zu) header from %s: %s\n",
elf_ndxscn(scn), obj->path, elf_errmsg(-1));
return -EINVAL;
}
return 0;
}
static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn)
{
const char *name;
GElf_Shdr sh;
if (!scn)
return NULL;
if (elf_sec_hdr(obj, scn, &sh))
return NULL;
name = elf_sec_str(obj, sh.sh_name);
if (!name) {
pr_warn("elf: failed to get section(%zu) name from %s: %s\n",
elf_ndxscn(scn), obj->path, elf_errmsg(-1));
return NULL;
}
return name;
}
static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn)
{
Elf_Data *data;
if (!scn)
return NULL;
data = elf_getdata(scn, 0);
if (!data) {
pr_warn("elf: failed to get section(%zu) %s data from %s: %s\n",
elf_ndxscn(scn), elf_sec_name(obj, scn) ?: "<?>",
obj->path, elf_errmsg(-1));
return NULL;
}
return data;
}
static int elf_sym_by_sec_off(const struct bpf_object *obj, size_t sec_idx,
size_t off, __u32 sym_type, GElf_Sym *sym)
{
Elf_Data *symbols = obj->efile.symbols;
size_t n = symbols->d_size / sizeof(GElf_Sym);
int i;
for (i = 0; i < n; i++) {
if (!gelf_getsym(symbols, i, sym))
continue;
if (sym->st_shndx != sec_idx || sym->st_value != off)
continue;
if (GELF_ST_TYPE(sym->st_info) != sym_type)
continue;
return 0;
}
return -ENOENT;
}
static bool is_sec_name_dwarf(const char *name)
{
/* approximation, but the actual list is too long */
return strncmp(name, ".debug_", sizeof(".debug_") - 1) == 0;
}
static bool ignore_elf_section(GElf_Shdr *hdr, const char *name)
{
/* no special handling of .strtab */
if (hdr->sh_type == SHT_STRTAB)
return true;
/* ignore .llvm_addrsig section as well */
if (hdr->sh_type == 0x6FFF4C03 /* SHT_LLVM_ADDRSIG */)
return true;
/* no subprograms will lead to an empty .text section, ignore it */
if (hdr->sh_type == SHT_PROGBITS && hdr->sh_size == 0 &&
strcmp(name, ".text") == 0)
return true;
/* DWARF sections */
if (is_sec_name_dwarf(name))
return true;
if (strncmp(name, ".rel", sizeof(".rel") - 1) == 0) {
name += sizeof(".rel") - 1;
/* DWARF section relocations */
if (is_sec_name_dwarf(name))
return true;
/* .BTF and .BTF.ext don't need relocations */
if (strcmp(name, BTF_ELF_SEC) == 0 ||
strcmp(name, BTF_EXT_ELF_SEC) == 0)
return true;
}
return false;
}
static int cmp_progs(const void *_a, const void *_b)
{
const struct bpf_program *a = _a;
const struct bpf_program *b = _b;
if (a->sec_idx != b->sec_idx)
return a->sec_idx < b->sec_idx ? -1 : 1;
/* sec_insn_off can't be the same within the section */
return a->sec_insn_off < b->sec_insn_off ? -1 : 1;
}
static int bpf_object__elf_collect(struct bpf_object *obj)
{
Elf *elf = obj->efile.elf;
Elf_Data *btf_ext_data = NULL;
Elf_Data *btf_data = NULL;
int idx = 0, err = 0;
const char *name;
Elf_Data *data;
Elf_Scn *scn;
GElf_Shdr sh;
/* a bunch of ELF parsing functionality depends on processing symbols,
* so do the first pass and find the symbol table
*/
scn = NULL;
while ((scn = elf_nextscn(elf, scn)) != NULL) {
if (elf_sec_hdr(obj, scn, &sh))
return -LIBBPF_ERRNO__FORMAT;
if (sh.sh_type == SHT_SYMTAB) {
if (obj->efile.symbols) {
pr_warn("elf: multiple symbol tables in %s\n", obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
data = elf_sec_data(obj, scn);
if (!data)
return -LIBBPF_ERRNO__FORMAT;
obj->efile.symbols = data;
obj->efile.symbols_shndx = elf_ndxscn(scn);
obj->efile.strtabidx = sh.sh_link;
}
}
scn = NULL;
while ((scn = elf_nextscn(elf, scn)) != NULL) {
idx++;
if (elf_sec_hdr(obj, scn, &sh))
return -LIBBPF_ERRNO__FORMAT;
name = elf_sec_str(obj, sh.sh_name);
if (!name)
return -LIBBPF_ERRNO__FORMAT;
if (ignore_elf_section(&sh, name))
continue;
data = elf_sec_data(obj, scn);
if (!data)
return -LIBBPF_ERRNO__FORMAT;
pr_debug("elf: section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
idx, name, (unsigned long)data->d_size,
(int)sh.sh_link, (unsigned long)sh.sh_flags,
(int)sh.sh_type);
if (strcmp(name, "license") == 0) {
err = bpf_object__init_license(obj, data->d_buf, data->d_size);
if (err)
return err;
} else if (strcmp(name, "version") == 0) {
err = bpf_object__init_kversion(obj, data->d_buf, data->d_size);
if (err)
return err;
} else if (strcmp(name, "maps") == 0) {
obj->efile.maps_shndx = idx;
} else if (strcmp(name, MAPS_ELF_SEC) == 0) {
obj->efile.btf_maps_shndx = idx;
} else if (strcmp(name, BTF_ELF_SEC) == 0) {
btf_data = data;
} else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
btf_ext_data = data;
} else if (sh.sh_type == SHT_SYMTAB) {
/* already processed during the first pass above */
} else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) {
if (sh.sh_flags & SHF_EXECINSTR) {
if (strcmp(name, ".text") == 0)
obj->efile.text_shndx = idx;
err = bpf_object__add_programs(obj, data, name, idx);
if (err)
return err;
} else if (strcmp(name, DATA_SEC) == 0) {
obj->efile.data = data;
obj->efile.data_shndx = idx;
} else if (strcmp(name, RODATA_SEC) == 0) {
obj->efile.rodata = data;
obj->efile.rodata_shndx = idx;
} else if (strcmp(name, STRUCT_OPS_SEC) == 0) {
obj->efile.st_ops_data = data;
obj->efile.st_ops_shndx = idx;
} else {
pr_info("elf: skipping unrecognized data section(%d) %s\n",
idx, name);
}
} else if (sh.sh_type == SHT_REL) {
int nr_sects = obj->efile.nr_reloc_sects;
void *sects = obj->efile.reloc_sects;
int sec = sh.sh_info; /* points to other section */
/* Only do relo for section with exec instructions */
if (!section_have_execinstr(obj, sec) &&
strcmp(name, ".rel" STRUCT_OPS_SEC) &&
strcmp(name, ".rel" MAPS_ELF_SEC)) {
pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n",
idx, name, sec,
elf_sec_name(obj, elf_sec_by_idx(obj, sec)) ?: "<?>");
continue;
}
sects = libbpf_reallocarray(sects, nr_sects + 1,
sizeof(*obj->efile.reloc_sects));
if (!sects)
return -ENOMEM;
obj->efile.reloc_sects = sects;
obj->efile.nr_reloc_sects++;
obj->efile.reloc_sects[nr_sects].shdr = sh;
obj->efile.reloc_sects[nr_sects].data = data;
} else if (sh.sh_type == SHT_NOBITS && strcmp(name, BSS_SEC) == 0) {
obj->efile.bss = data;
obj->efile.bss_shndx = idx;
} else {
pr_info("elf: skipping section(%d) %s (size %zu)\n", idx, name,
(size_t)sh.sh_size);
}
}
if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) {
pr_warn("elf: symbol strings section missing or invalid in %s\n", obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
/* sort BPF programs by section name and in-section instruction offset
* for faster search */
qsort(obj->programs, obj->nr_programs, sizeof(*obj->programs), cmp_progs);
return bpf_object__init_btf(obj, btf_data, btf_ext_data);
}
static bool sym_is_extern(const GElf_Sym *sym)
{
int bind = GELF_ST_BIND(sym->st_info);
/* externs are symbols w/ type=NOTYPE, bind=GLOBAL|WEAK, section=UND */
return sym->st_shndx == SHN_UNDEF &&
(bind == STB_GLOBAL || bind == STB_WEAK) &&
GELF_ST_TYPE(sym->st_info) == STT_NOTYPE;
}
static int find_extern_btf_id(const struct btf *btf, const char *ext_name)
{
const struct btf_type *t;
const char *var_name;
int i, n;
if (!btf)
return -ESRCH;
n = btf__get_nr_types(btf);
for (i = 1; i <= n; i++) {
t = btf__type_by_id(btf, i);
if (!btf_is_var(t))
continue;
var_name = btf__name_by_offset(btf, t->name_off);
if (strcmp(var_name, ext_name))
continue;
if (btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN)
return -EINVAL;
return i;
}
return -ENOENT;
}
static int find_extern_sec_btf_id(struct btf *btf, int ext_btf_id) {
const struct btf_var_secinfo *vs;
const struct btf_type *t;
int i, j, n;
if (!btf)
return -ESRCH;
n = btf__get_nr_types(btf);
for (i = 1; i <= n; i++) {
t = btf__type_by_id(btf, i);
if (!btf_is_datasec(t))
continue;
vs = btf_var_secinfos(t);
for (j = 0; j < btf_vlen(t); j++, vs++) {
if (vs->type == ext_btf_id)
return i;
}
}
return -ENOENT;
}
static enum kcfg_type find_kcfg_type(const struct btf *btf, int id,
bool *is_signed)
{
const struct btf_type *t;
const char *name;
t = skip_mods_and_typedefs(btf, id, NULL);
name = btf__name_by_offset(btf, t->name_off);
if (is_signed)
*is_signed = false;
switch (btf_kind(t)) {
case BTF_KIND_INT: {
int enc = btf_int_encoding(t);
if (enc & BTF_INT_BOOL)
return t->size == 1 ? KCFG_BOOL : KCFG_UNKNOWN;
if (is_signed)
*is_signed = enc & BTF_INT_SIGNED;
if (t->size == 1)
return KCFG_CHAR;
if (t->size < 1 || t->size > 8 || (t->size & (t->size - 1)))
return KCFG_UNKNOWN;
return KCFG_INT;
}
case BTF_KIND_ENUM:
if (t->size != 4)
return KCFG_UNKNOWN;
if (strcmp(name, "libbpf_tristate"))
return KCFG_UNKNOWN;
return KCFG_TRISTATE;
case BTF_KIND_ARRAY:
if (btf_array(t)->nelems == 0)
return KCFG_UNKNOWN;
if (find_kcfg_type(btf, btf_array(t)->type, NULL) != KCFG_CHAR)
return KCFG_UNKNOWN;
return KCFG_CHAR_ARR;
default:
return KCFG_UNKNOWN;
}
}
static int cmp_externs(const void *_a, const void *_b)
{
const struct extern_desc *a = _a;
const struct extern_desc *b = _b;
if (a->type != b->type)
return a->type < b->type ? -1 : 1;
if (a->type == EXT_KCFG) {
/* descending order by alignment requirements */
if (a->kcfg.align != b->kcfg.align)
return a->kcfg.align > b->kcfg.align ? -1 : 1;
/* ascending order by size, within same alignment class */
if (a->kcfg.sz != b->kcfg.sz)
return a->kcfg.sz < b->kcfg.sz ? -1 : 1;
}
/* resolve ties by name */
return strcmp(a->name, b->name);
}
static int find_int_btf_id(const struct btf *btf)
{
const struct btf_type *t;
int i, n;
n = btf__get_nr_types(btf);
for (i = 1; i <= n; i++) {
t = btf__type_by_id(btf, i);
if (btf_is_int(t) && btf_int_bits(t) == 32)
return i;
}
return 0;
}
static int bpf_object__collect_externs(struct bpf_object *obj)
{
struct btf_type *sec, *kcfg_sec = NULL, *ksym_sec = NULL;
const struct btf_type *t;
struct extern_desc *ext;
int i, n, off;
const char *ext_name, *sec_name;
Elf_Scn *scn;
GElf_Shdr sh;
if (!obj->efile.symbols)
return 0;
scn = elf_sec_by_idx(obj, obj->efile.symbols_shndx);
if (elf_sec_hdr(obj, scn, &sh))
return -LIBBPF_ERRNO__FORMAT;
n = sh.sh_size / sh.sh_entsize;
pr_debug("looking for externs among %d symbols...\n", n);
for (i = 0; i < n; i++) {
GElf_Sym sym;
if (!gelf_getsym(obj->efile.symbols, i, &sym))
return -LIBBPF_ERRNO__FORMAT;
if (!sym_is_extern(&sym))
continue;
ext_name = elf_sym_str(obj, sym.st_name);
if (!ext_name || !ext_name[0])
continue;
ext = obj->externs;
ext = libbpf_reallocarray(ext, obj->nr_extern + 1, sizeof(*ext));
if (!ext)
return -ENOMEM;
obj->externs = ext;
ext = &ext[obj->nr_extern];
memset(ext, 0, sizeof(*ext));
obj->nr_extern++;
ext->btf_id = find_extern_btf_id(obj->btf, ext_name);
if (ext->btf_id <= 0) {
pr_warn("failed to find BTF for extern '%s': %d\n",
ext_name, ext->btf_id);
return ext->btf_id;
}
t = btf__type_by_id(obj->btf, ext->btf_id);
ext->name = btf__name_by_offset(obj->btf, t->name_off);
ext->sym_idx = i;
ext->is_weak = GELF_ST_BIND(sym.st_info) == STB_WEAK;
ext->sec_btf_id = find_extern_sec_btf_id(obj->btf, ext->btf_id);
if (ext->sec_btf_id <= 0) {
pr_warn("failed to find BTF for extern '%s' [%d] section: %d\n",
ext_name, ext->btf_id, ext->sec_btf_id);
return ext->sec_btf_id;
}
sec = (void *)btf__type_by_id(obj->btf, ext->sec_btf_id);
sec_name = btf__name_by_offset(obj->btf, sec->name_off);
if (strcmp(sec_name, KCONFIG_SEC) == 0) {
kcfg_sec = sec;
ext->type = EXT_KCFG;
ext->kcfg.sz = btf__resolve_size(obj->btf, t->type);
if (ext->kcfg.sz <= 0) {
pr_warn("failed to resolve size of extern (kcfg) '%s': %d\n",
ext_name, ext->kcfg.sz);
return ext->kcfg.sz;
}
ext->kcfg.align = btf__align_of(obj->btf, t->type);
if (ext->kcfg.align <= 0) {
pr_warn("failed to determine alignment of extern (kcfg) '%s': %d\n",
ext_name, ext->kcfg.align);
return -EINVAL;
}
ext->kcfg.type = find_kcfg_type(obj->btf, t->type,
&ext->kcfg.is_signed);
if (ext->kcfg.type == KCFG_UNKNOWN) {
pr_warn("extern (kcfg) '%s' type is unsupported\n", ext_name);
return -ENOTSUP;
}
} else if (strcmp(sec_name, KSYMS_SEC) == 0) {
ksym_sec = sec;
ext->type = EXT_KSYM;
skip_mods_and_typedefs(obj->btf, t->type,
&ext->ksym.type_id);
} else {
pr_warn("unrecognized extern section '%s'\n", sec_name);
return -ENOTSUP;
}
}
pr_debug("collected %d externs total\n", obj->nr_extern);
if (!obj->nr_extern)
return 0;
/* sort externs by type, for kcfg ones also by (align, size, name) */
qsort(obj->externs, obj->nr_extern, sizeof(*ext), cmp_externs);
/* for .ksyms section, we need to turn all externs into allocated
* variables in BTF to pass kernel verification; we do this by
* pretending that each extern is a 8-byte variable
*/
if (ksym_sec) {
/* find existing 4-byte integer type in BTF to use for fake
* extern variables in DATASEC
*/
int int_btf_id = find_int_btf_id(obj->btf);
for (i = 0; i < obj->nr_extern; i++) {
ext = &obj->externs[i];
if (ext->type != EXT_KSYM)
continue;
pr_debug("extern (ksym) #%d: symbol %d, name %s\n",
i, ext->sym_idx, ext->name);
}
sec = ksym_sec;
n = btf_vlen(sec);
for (i = 0, off = 0; i < n; i++, off += sizeof(int)) {
struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i;
struct btf_type *vt;
vt = (void *)btf__type_by_id(obj->btf, vs->type);
ext_name = btf__name_by_offset(obj->btf, vt->name_off);
ext = find_extern_by_name(obj, ext_name);
if (!ext) {
pr_warn("failed to find extern definition for BTF var '%s'\n",
ext_name);
return -ESRCH;
}
btf_var(vt)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
vt->type = int_btf_id;
vs->offset = off;
vs->size = sizeof(int);
}
sec->size = off;
}
if (kcfg_sec) {
sec = kcfg_sec;
/* for kcfg externs calculate their offsets within a .kconfig map */
off = 0;
for (i = 0; i < obj->nr_extern; i++) {
ext = &obj->externs[i];
if (ext->type != EXT_KCFG)
continue;
ext->kcfg.data_off = roundup(off, ext->kcfg.align);
off = ext->kcfg.data_off + ext->kcfg.sz;
pr_debug("extern (kcfg) #%d: symbol %d, off %u, name %s\n",
i, ext->sym_idx, ext->kcfg.data_off, ext->name);
}
sec->size = off;
n = btf_vlen(sec);
for (i = 0; i < n; i++) {
struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i;
t = btf__type_by_id(obj->btf, vs->type);
ext_name = btf__name_by_offset(obj->btf, t->name_off);
ext = find_extern_by_name(obj, ext_name);
if (!ext) {
pr_warn("failed to find extern definition for BTF var '%s'\n",
ext_name);
return -ESRCH;
}
btf_var(t)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
vs->offset = ext->kcfg.data_off;
}
}
return 0;
}
struct bpf_program *
bpf_object__find_program_by_title(const struct bpf_object *obj,
const char *title)
{
struct bpf_program *pos;
bpf_object__for_each_program(pos, obj) {
if (pos->sec_name && !strcmp(pos->sec_name, title))
return pos;
}
return NULL;
}
static bool prog_is_subprog(const struct bpf_object *obj,
const struct bpf_program *prog)
{
/* For legacy reasons, libbpf supports an entry-point BPF programs
* without SEC() attribute, i.e., those in the .text section. But if
* there are 2 or more such programs in the .text section, they all
* must be subprograms called from entry-point BPF programs in
* designated SEC()'tions, otherwise there is no way to distinguish
* which of those programs should be loaded vs which are a subprogram.
* Similarly, if there is a function/program in .text and at least one
* other BPF program with custom SEC() attribute, then we just assume
* .text programs are subprograms (even if they are not called from
* other programs), because libbpf never explicitly supported mixing
* SEC()-designated BPF programs and .text entry-point BPF programs.
*/
return prog->sec_idx == obj->efile.text_shndx && obj->nr_programs > 1;
}
struct bpf_program *
bpf_object__find_program_by_name(const struct bpf_object *obj,
const char *name)
{
struct bpf_program *prog;
bpf_object__for_each_program(prog, obj) {
if (prog_is_subprog(obj, prog))
continue;
if (!strcmp(prog->name, name))
return prog;
}
return NULL;
}
static bool bpf_object__shndx_is_data(const struct bpf_object *obj,
int shndx)
{
return shndx == obj->efile.data_shndx ||
shndx == obj->efile.bss_shndx ||
shndx == obj->efile.rodata_shndx;
}
static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
int shndx)
{
return shndx == obj->efile.maps_shndx ||
shndx == obj->efile.btf_maps_shndx;
}
static enum libbpf_map_type
bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
{
if (shndx == obj->efile.data_shndx)
return LIBBPF_MAP_DATA;
else if (shndx == obj->efile.bss_shndx)
return LIBBPF_MAP_BSS;
else if (shndx == obj->efile.rodata_shndx)
return LIBBPF_MAP_RODATA;
else if (shndx == obj->efile.symbols_shndx)
return LIBBPF_MAP_KCONFIG;
else
return LIBBPF_MAP_UNSPEC;
}
static int bpf_program__record_reloc(struct bpf_program *prog,
struct reloc_desc *reloc_desc,
__u32 insn_idx, const char *sym_name,
const GElf_Sym *sym, const GElf_Rel *rel)
{
struct bpf_insn *insn = &prog->insns[insn_idx];
size_t map_idx, nr_maps = prog->obj->nr_maps;
struct bpf_object *obj = prog->obj;
__u32 shdr_idx = sym->st_shndx;
enum libbpf_map_type type;
const char *sym_sec_name;
struct bpf_map *map;
reloc_desc->processed = false;
/* sub-program call relocation */
if (insn->code == (BPF_JMP | BPF_CALL)) {
if (insn->src_reg != BPF_PSEUDO_CALL) {
pr_warn("prog '%s': incorrect bpf_call opcode\n", prog->name);
return -LIBBPF_ERRNO__RELOC;
}
/* text_shndx can be 0, if no default "main" program exists */
if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx));
pr_warn("prog '%s': bad call relo against '%s' in section '%s'\n",
prog->name, sym_name, sym_sec_name);
return -LIBBPF_ERRNO__RELOC;
}
if (sym->st_value % BPF_INSN_SZ) {
pr_warn("prog '%s': bad call relo against '%s' at offset %zu\n",
prog->name, sym_name, (size_t)sym->st_value);
return -LIBBPF_ERRNO__RELOC;
}
reloc_desc->type = RELO_CALL;
reloc_desc->insn_idx = insn_idx;
reloc_desc->sym_off = sym->st_value;
return 0;
}
if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) {
pr_warn("prog '%s': invalid relo against '%s' for insns[%d].code 0x%x\n",
prog->name, sym_name, insn_idx, insn->code);
return -LIBBPF_ERRNO__RELOC;
}
if (sym_is_extern(sym)) {
int sym_idx = GELF_R_SYM(rel->r_info);
int i, n = obj->nr_extern;
struct extern_desc *ext;
for (i = 0; i < n; i++) {
ext = &obj->externs[i];
if (ext->sym_idx == sym_idx)
break;
}
if (i >= n) {
pr_warn("prog '%s': extern relo failed to find extern for '%s' (%d)\n",
prog->name, sym_name, sym_idx);
return -LIBBPF_ERRNO__RELOC;
}
pr_debug("prog '%s': found extern #%d '%s' (sym %d) for insn #%u\n",
prog->name, i, ext->name, ext->sym_idx, insn_idx);
reloc_desc->type = RELO_EXTERN;
reloc_desc->insn_idx = insn_idx;
reloc_desc->sym_off = i; /* sym_off stores extern index */
return 0;
}
if (!shdr_idx || shdr_idx >= SHN_LORESERVE) {
pr_warn("prog '%s': invalid relo against '%s' in special section 0x%x; forgot to initialize global var?..\n",
prog->name, sym_name, shdr_idx);
return -LIBBPF_ERRNO__RELOC;
}
type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx));
/* generic map reference relocation */
if (type == LIBBPF_MAP_UNSPEC) {
if (!bpf_object__shndx_is_maps(obj, shdr_idx)) {
pr_warn("prog '%s': bad map relo against '%s' in section '%s'\n",
prog->name, sym_name, sym_sec_name);
return -LIBBPF_ERRNO__RELOC;
}
for (map_idx = 0; map_idx < nr_maps; map_idx++) {
map = &obj->maps[map_idx];
if (map->libbpf_type != type ||
map->sec_idx != sym->st_shndx ||
map->sec_offset != sym->st_value)
continue;
pr_debug("prog '%s': found map %zd (%s, sec %d, off %zu) for insn #%u\n",
prog->name, map_idx, map->name, map->sec_idx,
map->sec_offset, insn_idx);
break;
}
if (map_idx >= nr_maps) {
pr_warn("prog '%s': map relo failed to find map for section '%s', off %zu\n",
prog->name, sym_sec_name, (size_t)sym->st_value);
return -LIBBPF_ERRNO__RELOC;
}
reloc_desc->type = RELO_LD64;
reloc_desc->insn_idx = insn_idx;
reloc_desc->map_idx = map_idx;
reloc_desc->sym_off = 0; /* sym->st_value determines map_idx */
return 0;
}
/* global data map relocation */
if (!bpf_object__shndx_is_data(obj, shdr_idx)) {
pr_warn("prog '%s': bad data relo against section '%s'\n",
prog->name, sym_sec_name);
return -LIBBPF_ERRNO__RELOC;
}
for (map_idx = 0; map_idx < nr_maps; map_idx++) {
map = &obj->maps[map_idx];
if (map->libbpf_type != type)
continue;
pr_debug("prog '%s': found data map %zd (%s, sec %d, off %zu) for insn %u\n",
prog->name, map_idx, map->name, map->sec_idx,
map->sec_offset, insn_idx);
break;
}
if (map_idx >= nr_maps) {
pr_warn("prog '%s': data relo failed to find map for section '%s'\n",
prog->name, sym_sec_name);
return -LIBBPF_ERRNO__RELOC;
}
reloc_desc->type = RELO_DATA;
reloc_desc->insn_idx = insn_idx;
reloc_desc->map_idx = map_idx;
reloc_desc->sym_off = sym->st_value;
return 0;
}
static bool prog_contains_insn(const struct bpf_program *prog, size_t insn_idx)
{
return insn_idx >= prog->sec_insn_off &&
insn_idx < prog->sec_insn_off + prog->sec_insn_cnt;
}
static struct bpf_program *find_prog_by_sec_insn(const struct bpf_object *obj,
size_t sec_idx, size_t insn_idx)
{
int l = 0, r = obj->nr_programs - 1, m;
struct bpf_program *prog;
while (l < r) {
m = l + (r - l + 1) / 2;
prog = &obj->programs[m];
if (prog->sec_idx < sec_idx ||
(prog->sec_idx == sec_idx && prog->sec_insn_off <= insn_idx))
l = m;
else
r = m - 1;
}
/* matching program could be at index l, but it still might be the
* wrong one, so we need to double check conditions for the last time
*/
prog = &obj->programs[l];
if (prog->sec_idx == sec_idx && prog_contains_insn(prog, insn_idx))
return prog;
return NULL;
}
static int
bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data *data)
{
Elf_Data *symbols = obj->efile.symbols;
const char *relo_sec_name, *sec_name;
size_t sec_idx = shdr->sh_info;
struct bpf_program *prog;
struct reloc_desc *relos;
int err, i, nrels;
const char *sym_name;
__u32 insn_idx;
GElf_Sym sym;
GElf_Rel rel;
relo_sec_name = elf_sec_str(obj, shdr->sh_name);
sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx));
if (!relo_sec_name || !sec_name)
return -EINVAL;
pr_debug("sec '%s': collecting relocation for section(%zu) '%s'\n",
relo_sec_name, sec_idx, sec_name);
nrels = shdr->sh_size / shdr->sh_entsize;
for (i = 0; i < nrels; i++) {
if (!gelf_getrel(data, i, &rel)) {
pr_warn("sec '%s': failed to get relo #%d\n", relo_sec_name, i);
return -LIBBPF_ERRNO__FORMAT;
}
if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
pr_warn("sec '%s': symbol 0x%zx not found for relo #%d\n",
relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i);
return -LIBBPF_ERRNO__FORMAT;
}
if (rel.r_offset % BPF_INSN_SZ) {
pr_warn("sec '%s': invalid offset 0x%zx for relo #%d\n",
relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i);
return -LIBBPF_ERRNO__FORMAT;
}
insn_idx = rel.r_offset / BPF_INSN_SZ;
/* relocations against static functions are recorded as
* relocations against the section that contains a function;
* in such case, symbol will be STT_SECTION and sym.st_name
* will point to empty string (0), so fetch section name
* instead
*/
if (GELF_ST_TYPE(sym.st_info) == STT_SECTION && sym.st_name == 0)
sym_name = elf_sec_name(obj, elf_sec_by_idx(obj, sym.st_shndx));
else
sym_name = elf_sym_str(obj, sym.st_name);
sym_name = sym_name ?: "<?";
pr_debug("sec '%s': relo #%d: insn #%u against '%s'\n",
relo_sec_name, i, insn_idx, sym_name);
prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx);
if (!prog) {
pr_warn("sec '%s': relo #%d: program not found in section '%s' for insn #%u\n",
relo_sec_name, i, sec_name, insn_idx);
return -LIBBPF_ERRNO__RELOC;
}
relos = libbpf_reallocarray(prog->reloc_desc,
prog->nr_reloc + 1, sizeof(*relos));
if (!relos)
return -ENOMEM;
prog->reloc_desc = relos;
/* adjust insn_idx to local BPF program frame of reference */
insn_idx -= prog->sec_insn_off;
err = bpf_program__record_reloc(prog, &relos[prog->nr_reloc],
insn_idx, sym_name, &sym, &rel);
if (err)
return err;
prog->nr_reloc++;
}
return 0;
}
static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
{
struct bpf_map_def *def = &map->def;
__u32 key_type_id = 0, value_type_id = 0;
int ret;
/* if it's BTF-defined map, we don't need to search for type IDs.
* For struct_ops map, it does not need btf_key_type_id and
* btf_value_type_id.
*/
if (map->sec_idx == obj->efile.btf_maps_shndx ||
bpf_map__is_struct_ops(map))
return 0;
if (!bpf_map__is_internal(map)) {
ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size,
def->value_size, &key_type_id,
&value_type_id);
} else {
/*
* LLVM annotates global data differently in BTF, that is,
* only as '.data', '.bss' or '.rodata'.
*/
ret = btf__find_by_name(obj->btf,
libbpf_type_to_btf_name[map->libbpf_type]);
}
if (ret < 0)
return ret;
map->btf_key_type_id = key_type_id;
map->btf_value_type_id = bpf_map__is_internal(map) ?
ret : value_type_id;
return 0;
}
static int bpf_get_map_info_from_fdinfo(int fd, struct bpf_map_info *info)
{
char file[PATH_MAX], buff[4096];
FILE *fp;
__u32 val;
int err;
snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd);
memset(info, 0, sizeof(*info));
fp = fopen(file, "r");
if (!fp) {
err = -errno;
pr_warn("failed to open %s: %d. No procfs support?\n", file,
err);
return err;
}
while (fgets(buff, sizeof(buff), fp)) {
if (sscanf(buff, "map_type:\t%u", &val) == 1)
info->type = val;
else if (sscanf(buff, "key_size:\t%u", &val) == 1)
info->key_size = val;
else if (sscanf(buff, "value_size:\t%u", &val) == 1)
info->value_size = val;
else if (sscanf(buff, "max_entries:\t%u", &val) == 1)
info->max_entries = val;
else if (sscanf(buff, "map_flags:\t%i", &val) == 1)
info->map_flags = val;
}
fclose(fp);
return 0;
}
int bpf_map__reuse_fd(struct bpf_map *map, int fd)
{
struct bpf_map_info info = {};
__u32 len = sizeof(info);
int new_fd, err;
char *new_name;
err = bpf_obj_get_info_by_fd(fd, &info, &len);
if (err && errno == EINVAL)
err = bpf_get_map_info_from_fdinfo(fd, &info);
if (err)
return err;
new_name = strdup(info.name);
if (!new_name)
return -errno;
new_fd = open("/", O_RDONLY | O_CLOEXEC);
if (new_fd < 0) {
err = -errno;
goto err_free_new_name;
}
new_fd = dup3(fd, new_fd, O_CLOEXEC);
if (new_fd < 0) {
err = -errno;
goto err_close_new_fd;
}
err = zclose(map->fd);
if (err) {
err = -errno;
goto err_close_new_fd;
}
free(map->name);
map->fd = new_fd;
map->name = new_name;
map->def.type = info.type;
map->def.key_size = info.key_size;
map->def.value_size = info.value_size;
map->def.max_entries = info.max_entries;
map->def.map_flags = info.map_flags;
map->btf_key_type_id = info.btf_key_type_id;
map->btf_value_type_id = info.btf_value_type_id;
map->reused = true;
return 0;
err_close_new_fd:
close(new_fd);
err_free_new_name:
free(new_name);
return err;
}
__u32 bpf_map__max_entries(const struct bpf_map *map)
{
return map->def.max_entries;
}
int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries)
{
if (map->fd >= 0)
return -EBUSY;
map->def.max_entries = max_entries;
return 0;
}
int bpf_map__resize(struct bpf_map *map, __u32 max_entries)
{
if (!map || !max_entries)
return -EINVAL;
return bpf_map__set_max_entries(map, max_entries);
}
static int
bpf_object__probe_loading(struct bpf_object *obj)
{
struct bpf_load_program_attr attr;
char *cp, errmsg[STRERR_BUFSIZE];
struct bpf_insn insns[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
int ret;
/* make sure basic loading works */
memset(&attr, 0, sizeof(attr));
attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
attr.insns = insns;
attr.insns_cnt = ARRAY_SIZE(insns);
attr.license = "GPL";
ret = bpf_load_program_xattr(&attr, NULL, 0);
if (ret < 0) {
ret = errno;
cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
pr_warn("Error in %s():%s(%d). Couldn't load trivial BPF "
"program. Make sure your kernel supports BPF "
"(CONFIG_BPF_SYSCALL=y) and/or that RLIMIT_MEMLOCK is "
"set to big enough value.\n", __func__, cp, ret);
return -ret;
}
close(ret);
return 0;
}
static int probe_fd(int fd)
{
if (fd >= 0)
close(fd);
return fd >= 0;
}
static int probe_kern_prog_name(void)
{
struct bpf_load_program_attr attr;
struct bpf_insn insns[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
int ret;
/* make sure loading with name works */
memset(&attr, 0, sizeof(attr));
attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
attr.insns = insns;
attr.insns_cnt = ARRAY_SIZE(insns);
attr.license = "GPL";
attr.name = "test";
ret = bpf_load_program_xattr(&attr, NULL, 0);
return probe_fd(ret);
}
static int probe_kern_global_data(void)
{
struct bpf_load_program_attr prg_attr;
struct bpf_create_map_attr map_attr;
char *cp, errmsg[STRERR_BUFSIZE];
struct bpf_insn insns[] = {
BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
int ret, map;
memset(&map_attr, 0, sizeof(map_attr));
map_attr.map_type = BPF_MAP_TYPE_ARRAY;
map_attr.key_size = sizeof(int);
map_attr.value_size = 32;
map_attr.max_entries = 1;
map = bpf_create_map_xattr(&map_attr);
if (map < 0) {
ret = -errno;
cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
__func__, cp, -ret);
return ret;
}
insns[0].imm = map;
memset(&prg_attr, 0, sizeof(prg_attr));
prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
prg_attr.insns = insns;
prg_attr.insns_cnt = ARRAY_SIZE(insns);
prg_attr.license = "GPL";
ret = bpf_load_program_xattr(&prg_attr, NULL, 0);
close(map);
return probe_fd(ret);
}
static int probe_kern_btf(void)
{
static const char strs[] = "\0int";
__u32 types[] = {
/* int */
BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
};
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
strs, sizeof(strs)));
}
static int probe_kern_btf_func(void)
{
static const char strs[] = "\0int\0x\0a";
/* void x(int a) {} */
__u32 types[] = {
/* int */
BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
/* FUNC_PROTO */ /* [2] */
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
BTF_PARAM_ENC(7, 1),
/* FUNC x */ /* [3] */
BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
};
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
strs, sizeof(strs)));
}
static int probe_kern_btf_func_global(void)
{
static const char strs[] = "\0int\0x\0a";
/* static void x(int a) {} */
__u32 types[] = {
/* int */
BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
/* FUNC_PROTO */ /* [2] */
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
BTF_PARAM_ENC(7, 1),
/* FUNC x BTF_FUNC_GLOBAL */ /* [3] */
BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2),
};
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
strs, sizeof(strs)));
}
static int probe_kern_btf_datasec(void)
{
static const char strs[] = "\0x\0.data";
/* static int a; */
__u32 types[] = {
/* int */
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
/* VAR x */ /* [2] */
BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
BTF_VAR_STATIC,
/* DATASEC val */ /* [3] */
BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
BTF_VAR_SECINFO_ENC(2, 0, 4),
};
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
strs, sizeof(strs)));
}
static int probe_kern_array_mmap(void)
{
struct bpf_create_map_attr attr = {
.map_type = BPF_MAP_TYPE_ARRAY,
.map_flags = BPF_F_MMAPABLE,
.key_size = sizeof(int),
.value_size = sizeof(int),
.max_entries = 1,
};
return probe_fd(bpf_create_map_xattr(&attr));
}
static int probe_kern_exp_attach_type(void)
{
struct bpf_load_program_attr attr;
struct bpf_insn insns[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
memset(&attr, 0, sizeof(attr));
/* use any valid combination of program type and (optional)
* non-zero expected attach type (i.e., not a BPF_CGROUP_INET_INGRESS)
* to see if kernel supports expected_attach_type field for
* BPF_PROG_LOAD command
*/
attr.prog_type = BPF_PROG_TYPE_CGROUP_SOCK;
attr.expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE;
attr.insns = insns;
attr.insns_cnt = ARRAY_SIZE(insns);
attr.license = "GPL";
return probe_fd(bpf_load_program_xattr(&attr, NULL, 0));
}
static int probe_kern_probe_read_kernel(void)
{
struct bpf_load_program_attr attr;
struct bpf_insn insns[] = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), /* r1 = r10 (fp) */
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), /* r1 += -8 */
BPF_MOV64_IMM(BPF_REG_2, 8), /* r2 = 8 */
BPF_MOV64_IMM(BPF_REG_3, 0), /* r3 = 0 */
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_probe_read_kernel),
BPF_EXIT_INSN(),
};
memset(&attr, 0, sizeof(attr));
attr.prog_type = BPF_PROG_TYPE_KPROBE;
attr.insns = insns;
attr.insns_cnt = ARRAY_SIZE(insns);
attr.license = "GPL";
return probe_fd(bpf_load_program_xattr(&attr, NULL, 0));
}
static int probe_prog_bind_map(void)
{
struct bpf_load_program_attr prg_attr;
struct bpf_create_map_attr map_attr;
char *cp, errmsg[STRERR_BUFSIZE];
struct bpf_insn insns[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
int ret, map, prog;
memset(&map_attr, 0, sizeof(map_attr));
map_attr.map_type = BPF_MAP_TYPE_ARRAY;
map_attr.key_size = sizeof(int);
map_attr.value_size = 32;
map_attr.max_entries = 1;
map = bpf_create_map_xattr(&map_attr);
if (map < 0) {
ret = -errno;
cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
__func__, cp, -ret);
return ret;
}
memset(&prg_attr, 0, sizeof(prg_attr));
prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
prg_attr.insns = insns;
prg_attr.insns_cnt = ARRAY_SIZE(insns);
prg_attr.license = "GPL";
prog = bpf_load_program_xattr(&prg_attr, NULL, 0);
if (prog < 0) {
close(map);
return 0;
}
ret = bpf_prog_bind_map(prog, map, NULL);
close(map);
close(prog);
return ret >= 0;
}
enum kern_feature_result {
FEAT_UNKNOWN = 0,
FEAT_SUPPORTED = 1,
FEAT_MISSING = 2,
};
typedef int (*feature_probe_fn)(void);
static struct kern_feature_desc {
const char *desc;
feature_probe_fn probe;
enum kern_feature_result res;
} feature_probes[__FEAT_CNT] = {
[FEAT_PROG_NAME] = {
"BPF program name", probe_kern_prog_name,
},
[FEAT_GLOBAL_DATA] = {
"global variables", probe_kern_global_data,
},
[FEAT_BTF] = {
"minimal BTF", probe_kern_btf,
},
[FEAT_BTF_FUNC] = {
"BTF functions", probe_kern_btf_func,
},
[FEAT_BTF_GLOBAL_FUNC] = {
"BTF global function", probe_kern_btf_func_global,
},
[FEAT_BTF_DATASEC] = {
"BTF data section and variable", probe_kern_btf_datasec,
},
[FEAT_ARRAY_MMAP] = {
"ARRAY map mmap()", probe_kern_array_mmap,
},
[FEAT_EXP_ATTACH_TYPE] = {
"BPF_PROG_LOAD expected_attach_type attribute",
probe_kern_exp_attach_type,
},
[FEAT_PROBE_READ_KERN] = {
"bpf_probe_read_kernel() helper", probe_kern_probe_read_kernel,
},
[FEAT_PROG_BIND_MAP] = {
"BPF_PROG_BIND_MAP support", probe_prog_bind_map,
}
};
static bool kernel_supports(enum kern_feature_id feat_id)
{
struct kern_feature_desc *feat = &feature_probes[feat_id];
int ret;
if (READ_ONCE(feat->res) == FEAT_UNKNOWN) {
ret = feat->probe();
if (ret > 0) {
WRITE_ONCE(feat->res, FEAT_SUPPORTED);
} else if (ret == 0) {
WRITE_ONCE(feat->res, FEAT_MISSING);
} else {
pr_warn("Detection of kernel %s support failed: %d\n", feat->desc, ret);
WRITE_ONCE(feat->res, FEAT_MISSING);
}
}
return READ_ONCE(feat->res) == FEAT_SUPPORTED;
}
static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)
{
struct bpf_map_info map_info = {};
char msg[STRERR_BUFSIZE];
__u32 map_info_len;
int err;
map_info_len = sizeof(map_info);
err = bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len);
if (err && errno == EINVAL)
err = bpf_get_map_info_from_fdinfo(map_fd, &map_info);
if (err) {
pr_warn("failed to get map info for map FD %d: %s\n", map_fd,
libbpf_strerror_r(errno, msg, sizeof(msg)));
return false;
}
return (map_info.type == map->def.type &&
map_info.key_size == map->def.key_size &&
map_info.value_size == map->def.value_size &&
map_info.max_entries == map->def.max_entries &&
map_info.map_flags == map->def.map_flags);
}
static int
bpf_object__reuse_map(struct bpf_map *map)
{
char *cp, errmsg[STRERR_BUFSIZE];
int err, pin_fd;
pin_fd = bpf_obj_get(map->pin_path);
if (pin_fd < 0) {
err = -errno;
if (err == -ENOENT) {
pr_debug("found no pinned map to reuse at '%s'\n",
map->pin_path);
return 0;
}
cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
pr_warn("couldn't retrieve pinned map '%s': %s\n",
map->pin_path, cp);
return err;
}
if (!map_is_reuse_compat(map, pin_fd)) {
pr_warn("couldn't reuse pinned map at '%s': parameter mismatch\n",
map->pin_path);
close(pin_fd);
return -EINVAL;
}
err = bpf_map__reuse_fd(map, pin_fd);
if (err) {
close(pin_fd);
return err;
}
map->pinned = true;
pr_debug("reused pinned map at '%s'\n", map->pin_path);
return 0;
}
static int
bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
{
enum libbpf_map_type map_type = map->libbpf_type;
char *cp, errmsg[STRERR_BUFSIZE];
int err, zero = 0;
err = bpf_map_update_elem(map->fd, &zero, map->mmaped, 0);
if (err) {
err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("Error setting initial map(%s) contents: %s\n",
map->name, cp);
return err;
}
/* Freeze .rodata and .kconfig map as read-only from syscall side. */
if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG) {
err = bpf_map_freeze(map->fd);
if (err) {
err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("Error freezing map(%s) as read-only: %s\n",
map->name, cp);
return err;
}
}
return 0;
}
static void bpf_map__destroy(struct bpf_map *map);
static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map)
{
struct bpf_create_map_attr create_attr;
struct bpf_map_def *def = &map->def;
int err = 0;
memset(&create_attr, 0, sizeof(create_attr));
if (kernel_supports(FEAT_PROG_NAME))
create_attr.name = map->name;
create_attr.map_ifindex = map->map_ifindex;
create_attr.map_type = def->type;
create_attr.map_flags = def->map_flags;
create_attr.key_size = def->key_size;
create_attr.value_size = def->value_size;
create_attr.numa_node = map->numa_node;
if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !def->max_entries) {
int nr_cpus;
nr_cpus = libbpf_num_possible_cpus();
if (nr_cpus < 0) {
pr_warn("map '%s': failed to determine number of system CPUs: %d\n",
map->name, nr_cpus);
return nr_cpus;
}
pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus);
create_attr.max_entries = nr_cpus;
} else {
create_attr.max_entries = def->max_entries;
}
if (bpf_map__is_struct_ops(map))
create_attr.btf_vmlinux_value_type_id =
map->btf_vmlinux_value_type_id;
create_attr.btf_fd = 0;
create_attr.btf_key_type_id = 0;
create_attr.btf_value_type_id = 0;
if (obj->btf && btf__fd(obj->btf) >= 0 && !bpf_map_find_btf_info(obj, map)) {
create_attr.btf_fd = btf__fd(obj->btf);
create_attr.btf_key_type_id = map->btf_key_type_id;
create_attr.btf_value_type_id = map->btf_value_type_id;
}
if (bpf_map_type__is_map_in_map(def->type)) {
if (map->inner_map) {
err = bpf_object__create_map(obj, map->inner_map);
if (err) {
pr_warn("map '%s': failed to create inner map: %d\n",
map->name, err);
return err;
}
map->inner_map_fd = bpf_map__fd(map->inner_map);
}
if (map->inner_map_fd >= 0)
create_attr.inner_map_fd = map->inner_map_fd;
}
map->fd = bpf_create_map_xattr(&create_attr);
if (map->fd < 0 && (create_attr.btf_key_type_id ||
create_attr.btf_value_type_id)) {
char *cp, errmsg[STRERR_BUFSIZE];
err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
map->name, cp, err);
create_attr.btf_fd = 0;
create_attr.btf_key_type_id = 0;
create_attr.btf_value_type_id = 0;
map->btf_key_type_id = 0;
map->btf_value_type_id = 0;
map->fd = bpf_create_map_xattr(&create_attr);
}
err = map->fd < 0 ? -errno : 0;
if (bpf_map_type__is_map_in_map(def->type) && map->inner_map) {
bpf_map__destroy(map->inner_map);
zfree(&map->inner_map);
}
return err;
}
static int init_map_slots(struct bpf_map *map)
{
const struct bpf_map *targ_map;
unsigned int i;
int fd, err;
for (i = 0; i < map->init_slots_sz; i++) {
if (!map->init_slots[i])
continue;
targ_map = map->init_slots[i];
fd = bpf_map__fd(targ_map);
err = bpf_map_update_elem(map->fd, &i, &fd, 0);
if (err) {
err = -errno;
pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n",
map->name, i, targ_map->name,
fd, err);
return err;
}
pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n",
map->name, i, targ_map->name, fd);
}
zfree(&map->init_slots);
map->init_slots_sz = 0;
return 0;
}
static int
bpf_object__create_maps(struct bpf_object *obj)
{
struct bpf_map *map;
char *cp, errmsg[STRERR_BUFSIZE];
unsigned int i, j;
int err;
bool retried;
for (i = 0; i < obj->nr_maps; i++) {
map = &obj->maps[i];
retried = false;
retry:
if (map->pin_path) {
err = bpf_object__reuse_map(map);
if (err) {
pr_warn("map '%s': error reusing pinned map\n",
map->name);
goto err_out;
}
if (retried && map->fd < 0) {
pr_warn("map '%s': cannot find pinned map\n",
map->name);
err = -ENOENT;
goto err_out;
}
}
if (map->fd >= 0) {
pr_debug("map '%s': skipping creation (preset fd=%d)\n",
map->name, map->fd);
} else {
err = bpf_object__create_map(obj, map);
if (err)
goto err_out;
pr_debug("map '%s': created successfully, fd=%d\n",
map->name, map->fd);
if (bpf_map__is_internal(map)) {
err = bpf_object__populate_internal_map(obj, map);
if (err < 0) {
zclose(map->fd);
goto err_out;
}
}
if (map->init_slots_sz) {
err = init_map_slots(map);
if (err < 0) {
zclose(map->fd);
goto err_out;
}
}
}
if (map->pin_path && !map->pinned) {
err = bpf_map__pin(map, NULL);
if (err) {
zclose(map->fd);
if (!retried && err == -EEXIST) {
retried = true;
goto retry;
}
pr_warn("map '%s': failed to auto-pin at '%s': %d\n",
map->name, map->pin_path, err);
goto err_out;
}
}
}
return 0;
err_out:
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("map '%s': failed to create: %s(%d)\n", map->name, cp, err);
pr_perm_msg(err);
for (j = 0; j < i; j++)
zclose(obj->maps[j].fd);
return err;
}
#define BPF_CORE_SPEC_MAX_LEN 64
/* represents BPF CO-RE field or array element accessor */
struct bpf_core_accessor {
__u32 type_id; /* struct/union type or array element type */
__u32 idx; /* field index or array index */
const char *name; /* field name or NULL for array accessor */
};
struct bpf_core_spec {
const struct btf *btf;
/* high-level spec: named fields and array indices only */
struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN];
/* original unresolved (no skip_mods_or_typedefs) root type ID */
__u32 root_type_id;
/* CO-RE relocation kind */
enum bpf_core_relo_kind relo_kind;
/* high-level spec length */
int len;
/* raw, low-level spec: 1-to-1 with accessor spec string */
int raw_spec[BPF_CORE_SPEC_MAX_LEN];
/* raw spec length */
int raw_len;
/* field bit offset represented by spec */
__u32 bit_offset;
};
static bool str_is_empty(const char *s)
{
return !s || !s[0];
}
static bool is_flex_arr(const struct btf *btf,
const struct bpf_core_accessor *acc,
const struct btf_array *arr)
{
const struct btf_type *t;
/* not a flexible array, if not inside a struct or has non-zero size */
if (!acc->name || arr->nelems > 0)
return false;
/* has to be the last member of enclosing struct */
t = btf__type_by_id(btf, acc->type_id);
return acc->idx == btf_vlen(t) - 1;
}
static const char *core_relo_kind_str(enum bpf_core_relo_kind kind)
{
switch (kind) {
case BPF_FIELD_BYTE_OFFSET: return "byte_off";
case BPF_FIELD_BYTE_SIZE: return "byte_sz";
case BPF_FIELD_EXISTS: return "field_exists";
case BPF_FIELD_SIGNED: return "signed";
case BPF_FIELD_LSHIFT_U64: return "lshift_u64";
case BPF_FIELD_RSHIFT_U64: return "rshift_u64";
case BPF_TYPE_ID_LOCAL: return "local_type_id";
case BPF_TYPE_ID_TARGET: return "target_type_id";
case BPF_TYPE_EXISTS: return "type_exists";
case BPF_TYPE_SIZE: return "type_size";
case BPF_ENUMVAL_EXISTS: return "enumval_exists";
case BPF_ENUMVAL_VALUE: return "enumval_value";
default: return "unknown";
}
}
static bool core_relo_is_field_based(enum bpf_core_relo_kind kind)
{
switch (kind) {
case BPF_FIELD_BYTE_OFFSET:
case BPF_FIELD_BYTE_SIZE:
case BPF_FIELD_EXISTS:
case BPF_FIELD_SIGNED:
case BPF_FIELD_LSHIFT_U64:
case BPF_FIELD_RSHIFT_U64:
return true;
default:
return false;
}
}
static bool core_relo_is_type_based(enum bpf_core_relo_kind kind)
{
switch (kind) {
case BPF_TYPE_ID_LOCAL:
case BPF_TYPE_ID_TARGET:
case BPF_TYPE_EXISTS:
case BPF_TYPE_SIZE:
return true;
default:
return false;
}
}
static bool core_relo_is_enumval_based(enum bpf_core_relo_kind kind)
{
switch (kind) {
case BPF_ENUMVAL_EXISTS:
case BPF_ENUMVAL_VALUE:
return true;
default:
return false;
}
}
/*
* Turn bpf_core_relo into a low- and high-level spec representation,
* validating correctness along the way, as well as calculating resulting
* field bit offset, specified by accessor string. Low-level spec captures
* every single level of nestedness, including traversing anonymous
* struct/union members. High-level one only captures semantically meaningful
* "turning points": named fields and array indicies.
* E.g., for this case:
*
* struct sample {
* int __unimportant;
* struct {
* int __1;
* int __2;
* int a[7];
* };
* };
*
* struct sample *s = ...;
*
* int x = &s->a[3]; // access string = '0:1:2:3'
*
* Low-level spec has 1:1 mapping with each element of access string (it's
* just a parsed access string representation): [0, 1, 2, 3].
*
* High-level spec will capture only 3 points:
* - intial zero-index access by pointer (&s->... is the same as &s[0]...);
* - field 'a' access (corresponds to '2' in low-level spec);
* - array element #3 access (corresponds to '3' in low-level spec).
*
* Type-based relocations (TYPE_EXISTS/TYPE_SIZE,
* TYPE_ID_LOCAL/TYPE_ID_TARGET) don't capture any field information. Their
* spec and raw_spec are kept empty.
*
* Enum value-based relocations (ENUMVAL_EXISTS/ENUMVAL_VALUE) use access
* string to specify enumerator's value index that need to be relocated.
*/
static int bpf_core_parse_spec(const struct btf *btf,
__u32 type_id,
const char *spec_str,
enum bpf_core_relo_kind relo_kind,
struct bpf_core_spec *spec)
{
int access_idx, parsed_len, i;
struct bpf_core_accessor *acc;
const struct btf_type *t;
const char *name;
__u32 id;
__s64 sz;
if (str_is_empty(spec_str) || *spec_str == ':')
return -EINVAL;
memset(spec, 0, sizeof(*spec));
spec->btf = btf;
spec->root_type_id = type_id;
spec->relo_kind = relo_kind;
/* type-based relocations don't have a field access string */
if (core_relo_is_type_based(relo_kind)) {
if (strcmp(spec_str, "0"))
return -EINVAL;
return 0;
}
/* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */
while (*spec_str) {
if (*spec_str == ':')
++spec_str;
if (sscanf(spec_str, "%d%n", &access_idx, &parsed_len) != 1)
return -EINVAL;
if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
return -E2BIG;
spec_str += parsed_len;
spec->raw_spec[spec->raw_len++] = access_idx;
}
if (spec->raw_len == 0)
return -EINVAL;
t = skip_mods_and_typedefs(btf, type_id, &id);
if (!t)
return -EINVAL;
access_idx = spec->raw_spec[0];
acc = &spec->spec[0];
acc->type_id = id;
acc->idx = access_idx;
spec->len++;
if (core_relo_is_enumval_based(relo_kind)) {
if (!btf_is_enum(t) || spec->raw_len > 1 || access_idx >= btf_vlen(t))
return -EINVAL;
/* record enumerator name in a first accessor */
acc->name = btf__name_by_offset(btf, btf_enum(t)[access_idx].name_off);
return 0;
}
if (!core_relo_is_field_based(relo_kind))
return -EINVAL;
sz = btf__resolve_size(btf, id);
if (sz < 0)
return sz;
spec->bit_offset = access_idx * sz * 8;
for (i = 1; i < spec->raw_len; i++) {
t = skip_mods_and_typedefs(btf, id, &id);
if (!t)
return -EINVAL;
access_idx = spec->raw_spec[i];
acc = &spec->spec[spec->len];
if (btf_is_composite(t)) {
const struct btf_member *m;
__u32 bit_offset;
if (access_idx >= btf_vlen(t))
return -EINVAL;
bit_offset = btf_member_bit_offset(t, access_idx);
spec->bit_offset += bit_offset;
m = btf_members(t) + access_idx;
if (m->name_off) {
name = btf__name_by_offset(btf, m->name_off);
if (str_is_empty(name))
return -EINVAL;
acc->type_id = id;
acc->idx = access_idx;
acc->name = name;
spec->len++;
}
id = m->type;
} else if (btf_is_array(t)) {
const struct btf_array *a = btf_array(t);
bool flex;
t = skip_mods_and_typedefs(btf, a->type, &id);
if (!t)
return -EINVAL;
flex = is_flex_arr(btf, acc - 1, a);
if (!flex && access_idx >= a->nelems)
return -EINVAL;
spec->spec[spec->len].type_id = id;
spec->spec[spec->len].idx = access_idx;
spec->len++;
sz = btf__resolve_size(btf, id);
if (sz < 0)
return sz;
spec->bit_offset += access_idx * sz * 8;
} else {
pr_warn("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %s\n",
type_id, spec_str, i, id, btf_kind_str(t));
return -EINVAL;
}
}
return 0;
}
static bool bpf_core_is_flavor_sep(const char *s)
{
/* check X___Y name pattern, where X and Y are not underscores */
return s[0] != '_' && /* X */
s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
s[4] != '_'; /* Y */
}
/* Given 'some_struct_name___with_flavor' return the length of a name prefix
* before last triple underscore. Struct name part after last triple
* underscore is ignored by BPF CO-RE relocation during relocation matching.
*/
static size_t bpf_core_essential_name_len(const char *name)
{
size_t n = strlen(name);
int i;
for (i = n - 5; i >= 0; i--) {
if (bpf_core_is_flavor_sep(name + i))
return i + 1;
}
return n;
}
/* dynamically sized list of type IDs */
struct ids_vec {
__u32 *data;
int len;
};
static void bpf_core_free_cands(struct ids_vec *cand_ids)
{
free(cand_ids->data);
free(cand_ids);
}
static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
__u32 local_type_id,
const struct btf *targ_btf)
{
size_t local_essent_len, targ_essent_len;
const char *local_name, *targ_name;
const struct btf_type *t, *local_t;
struct ids_vec *cand_ids;
__u32 *new_ids;
int i, err, n;
local_t = btf__type_by_id(local_btf, local_type_id);
if (!local_t)
return ERR_PTR(-EINVAL);
local_name = btf__name_by_offset(local_btf, local_t->name_off);
if (str_is_empty(local_name))
return ERR_PTR(-EINVAL);
local_essent_len = bpf_core_essential_name_len(local_name);
cand_ids = calloc(1, sizeof(*cand_ids));
if (!cand_ids)
return ERR_PTR(-ENOMEM);
n = btf__get_nr_types(targ_btf);
for (i = 1; i <= n; i++) {
t = btf__type_by_id(targ_btf, i);
if (btf_kind(t) != btf_kind(local_t))
continue;
targ_name = btf__name_by_offset(targ_btf, t->name_off);
if (str_is_empty(targ_name))
continue;
targ_essent_len = bpf_core_essential_name_len(targ_name);
if (targ_essent_len != local_essent_len)
continue;
if (strncmp(local_name, targ_name, local_essent_len) == 0) {
pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s\n",
local_type_id, btf_kind_str(local_t),
local_name, i, btf_kind_str(t), targ_name);
new_ids = libbpf_reallocarray(cand_ids->data,
cand_ids->len + 1,
sizeof(*cand_ids->data));
if (!new_ids) {
err = -ENOMEM;
goto err_out;
}
cand_ids->data = new_ids;
cand_ids->data[cand_ids->len++] = i;
}
}
return cand_ids;
err_out:
bpf_core_free_cands(cand_ids);
return ERR_PTR(err);
}
/* Check two types for compatibility for the purpose of field access
* relocation. const/volatile/restrict and typedefs are skipped to ensure we
* are relocating semantically compatible entities:
* - any two STRUCTs/UNIONs are compatible and can be mixed;
* - any two FWDs are compatible, if their names match (modulo flavor suffix);
* - any two PTRs are always compatible;
* - for ENUMs, names should be the same (ignoring flavor suffix) or at
* least one of enums should be anonymous;
* - for ENUMs, check sizes, names are ignored;
* - for INT, size and signedness are ignored;
* - for ARRAY, dimensionality is ignored, element types are checked for
* compatibility recursively;
* - everything else shouldn't be ever a target of relocation.
* These rules are not set in stone and probably will be adjusted as we get
* more experience with using BPF CO-RE relocations.
*/
static int bpf_core_fields_are_compat(const struct btf *local_btf,
__u32 local_id,
const struct btf *targ_btf,
__u32 targ_id)
{
const struct btf_type *local_type, *targ_type;
recur:
local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
if (!local_type || !targ_type)
return -EINVAL;
if (btf_is_composite(local_type) && btf_is_composite(targ_type))
return 1;
if (btf_kind(local_type) != btf_kind(targ_type))
return 0;
switch (btf_kind(local_type)) {
case BTF_KIND_PTR:
return 1;
case BTF_KIND_FWD:
case BTF_KIND_ENUM: {
const char *local_name, *targ_name;
size_t local_len, targ_len;
local_name = btf__name_by_offset(local_btf,
local_type->name_off);
targ_name = btf__name_by_offset(targ_btf, targ_type->name_off);
local_len = bpf_core_essential_name_len(local_name);
targ_len = bpf_core_essential_name_len(targ_name);
/* one of them is anonymous or both w/ same flavor-less names */
return local_len == 0 || targ_len == 0 ||
(local_len == targ_len &&
strncmp(local_name, targ_name, local_len) == 0);
}
case BTF_KIND_INT:
/* just reject deprecated bitfield-like integers; all other
* integers are by default compatible between each other
*/
return btf_int_offset(local_type) == 0 &&
btf_int_offset(targ_type) == 0;
case BTF_KIND_ARRAY:
local_id = btf_array(local_type)->type;
targ_id = btf_array(targ_type)->type;
goto recur;
default:
pr_warn("unexpected kind %d relocated, local [%d], target [%d]\n",
btf_kind(local_type), local_id, targ_id);
return 0;
}
}
/*
* Given single high-level named field accessor in local type, find
* corresponding high-level accessor for a target type. Along the way,
* maintain low-level spec for target as well. Also keep updating target
* bit offset.
*
* Searching is performed through recursive exhaustive enumeration of all
* fields of a struct/union. If there are any anonymous (embedded)
* structs/unions, they are recursively searched as well. If field with
* desired name is found, check compatibility between local and target types,
* before returning result.
*
* 1 is returned, if field is found.
* 0 is returned if no compatible field is found.
* <0 is returned on error.
*/
static int bpf_core_match_member(const struct btf *local_btf,
const struct bpf_core_accessor *local_acc,
const struct btf *targ_btf,
__u32 targ_id,
struct bpf_core_spec *spec,
__u32 *next_targ_id)
{
const struct btf_type *local_type, *targ_type;
const struct btf_member *local_member, *m;
const char *local_name, *targ_name;
__u32 local_id;
int i, n, found;
targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
if (!targ_type)
return -EINVAL;
if (!btf_is_composite(targ_type))
return 0;
local_id = local_acc->type_id;
local_type = btf__type_by_id(local_btf, local_id);
local_member = btf_members(local_type) + local_acc->idx;
local_name = btf__name_by_offset(local_btf, local_member->name_off);
n = btf_vlen(targ_type);
m = btf_members(targ_type);
for (i = 0; i < n; i++, m++) {
__u32 bit_offset;
bit_offset = btf_member_bit_offset(targ_type, i);
/* too deep struct/union/array nesting */
if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
return -E2BIG;
/* speculate this member will be the good one */
spec->bit_offset += bit_offset;
spec->raw_spec[spec->raw_len++] = i;
targ_name = btf__name_by_offset(targ_btf, m->name_off);
if (str_is_empty(targ_name)) {
/* embedded struct/union, we need to go deeper */
found = bpf_core_match_member(local_btf, local_acc,
targ_btf, m->type,
spec, next_targ_id);
if (found) /* either found or error */
return found;
} else if (strcmp(local_name, targ_name) == 0) {
/* matching named field */
struct bpf_core_accessor *targ_acc;
targ_acc = &spec->spec[spec->len++];
targ_acc->type_id = targ_id;
targ_acc->idx = i;
targ_acc->name = targ_name;
*next_targ_id = m->type;
found = bpf_core_fields_are_compat(local_btf,
local_member->type,
targ_btf, m->type);
if (!found)
spec->len--; /* pop accessor */
return found;
}
/* member turned out not to be what we looked for */
spec->bit_offset -= bit_offset;
spec->raw_len--;
}
return 0;
}
/* Check local and target types for compatibility. This check is used for
* type-based CO-RE relocations and follow slightly different rules than
* field-based relocations. This function assumes that root types were already
* checked for name match. Beyond that initial root-level name check, names
* are completely ignored. Compatibility rules are as follows:
* - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but
* kind should match for local and target types (i.e., STRUCT is not
* compatible with UNION);
* - for ENUMs, the size is ignored;
* - for INT, size and signedness are ignored;
* - for ARRAY, dimensionality is ignored, element types are checked for
* compatibility recursively;
* - CONST/VOLATILE/RESTRICT modifiers are ignored;
* - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
* - FUNC_PROTOs are compatible if they have compatible signature: same
* number of input args and compatible return and argument types.
* These rules are not set in stone and probably will be adjusted as we get
* more experience with using BPF CO-RE relocations.
*/
static int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
const struct btf *targ_btf, __u32 targ_id)
{
const struct btf_type *local_type, *targ_type;
int depth = 32; /* max recursion depth */
/* caller made sure that names match (ignoring flavor suffix) */
local_type = btf__type_by_id(local_btf, local_id);
targ_type = btf__type_by_id(targ_btf, targ_id);
if (btf_kind(local_type) != btf_kind(targ_type))
return 0;
recur:
depth--;
if (depth < 0)
return -EINVAL;
local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
if (!local_type || !targ_type)
return -EINVAL;
if (btf_kind(local_type) != btf_kind(targ_type))
return 0;
switch (btf_kind(local_type)) {
case BTF_KIND_UNKN:
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
case BTF_KIND_ENUM:
case BTF_KIND_FWD:
return 1;
case BTF_KIND_INT:
/* just reject deprecated bitfield-like integers; all other
* integers are by default compatible between each other
*/
return btf_int_offset(local_type) == 0 && btf_int_offset(targ_type) == 0;
case BTF_KIND_PTR:
local_id = local_type->type;
targ_id = targ_type->type;
goto recur;
case BTF_KIND_ARRAY:
local_id = btf_array(local_type)->type;
targ_id = btf_array(targ_type)->type;
goto recur;
case BTF_KIND_FUNC_PROTO: {
struct btf_param *local_p = btf_params(local_type);
struct btf_param *targ_p = btf_params(targ_type);
__u16 local_vlen = btf_vlen(local_type);
__u16 targ_vlen = btf_vlen(targ_type);
int i, err;
if (local_vlen != targ_vlen)
return 0;
for (i = 0; i < local_vlen; i++, local_p++, targ_p++) {
skip_mods_and_typedefs(local_btf, local_p->type, &local_id);
skip_mods_and_typedefs(targ_btf, targ_p->type, &targ_id);
err = bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id);
if (err <= 0)
return err;
}
/* tail recurse for return type check */
skip_mods_and_typedefs(local_btf, local_type->type, &local_id);
skip_mods_and_typedefs(targ_btf, targ_type->type, &targ_id);
goto recur;
}
default:
pr_warn("unexpected kind %s relocated, local [%d], target [%d]\n",
btf_kind_str(local_type), local_id, targ_id);
return 0;
}
}
/*
* Try to match local spec to a target type and, if successful, produce full
* target spec (high-level, low-level + bit offset).
*/
static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
const struct btf *targ_btf, __u32 targ_id,
struct bpf_core_spec *targ_spec)
{
const struct btf_type *targ_type;
const struct bpf_core_accessor *local_acc;
struct bpf_core_accessor *targ_acc;
int i, sz, matched;
memset(targ_spec, 0, sizeof(*targ_spec));
targ_spec->btf = targ_btf;
targ_spec->root_type_id = targ_id;
targ_spec->relo_kind = local_spec->relo_kind;
if (core_relo_is_type_based(local_spec->relo_kind)) {
return bpf_core_types_are_compat(local_spec->btf,
local_spec->root_type_id,
targ_btf, targ_id);
}
local_acc = &local_spec->spec[0];
targ_acc = &targ_spec->spec[0];
if (core_relo_is_enumval_based(local_spec->relo_kind)) {
size_t local_essent_len, targ_essent_len;
const struct btf_enum *e;
const char *targ_name;
/* has to resolve to an enum */
targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id, &targ_id);
if (!btf_is_enum(targ_type))
return 0;
local_essent_len = bpf_core_essential_name_len(local_acc->name);
for (i = 0, e = btf_enum(targ_type); i < btf_vlen(targ_type); i++, e++) {
targ_name = btf__name_by_offset(targ_spec->btf, e->name_off);
targ_essent_len = bpf_core_essential_name_len(targ_name);
if (targ_essent_len != local_essent_len)
continue;
if (strncmp(local_acc->name, targ_name, local_essent_len) == 0) {
targ_acc->type_id = targ_id;
targ_acc->idx = i;
targ_acc->name = targ_name;
targ_spec->len++;
targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
targ_spec->raw_len++;
return 1;
}
}
return 0;
}
if (!core_relo_is_field_based(local_spec->relo_kind))
return -EINVAL;
for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) {
targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id,
&targ_id);
if (!targ_type)
return -EINVAL;
if (local_acc->name) {
matched = bpf_core_match_member(local_spec->btf,
local_acc,
targ_btf, targ_id,
targ_spec, &targ_id);
if (matched <= 0)
return matched;
} else {
/* for i=0, targ_id is already treated as array element
* type (because it's the original struct), for others
* we should find array element type first
*/
if (i > 0) {
const struct btf_array *a;
bool flex;
if (!btf_is_array(targ_type))
return 0;
a = btf_array(targ_type);
flex = is_flex_arr(targ_btf, targ_acc - 1, a);
if (!flex && local_acc->idx >= a->nelems)
return 0;
if (!skip_mods_and_typedefs(targ_btf, a->type,
&targ_id))
return -EINVAL;
}
/* too deep struct/union/array nesting */
if (targ_spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
return -E2BIG;
targ_acc->type_id = targ_id;
targ_acc->idx = local_acc->idx;
targ_acc->name = NULL;
targ_spec->len++;
targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
targ_spec->raw_len++;
sz = btf__resolve_size(targ_btf, targ_id);
if (sz < 0)
return sz;
targ_spec->bit_offset += local_acc->idx * sz * 8;
}
}
return 1;
}
static int bpf_core_calc_field_relo(const struct bpf_program *prog,
const struct bpf_core_relo *relo,
const struct bpf_core_spec *spec,
__u32 *val, __u32 *field_sz, __u32 *type_id,
bool *validate)
{
const struct bpf_core_accessor *acc;
const struct btf_type *t;
__u32 byte_off, byte_sz, bit_off, bit_sz, field_type_id;
const struct btf_member *m;
const struct btf_type *mt;
bool bitfield;
__s64 sz;
*field_sz = 0;
if (relo->kind == BPF_FIELD_EXISTS) {
*val = spec ? 1 : 0;
return 0;
}
if (!spec)
return -EUCLEAN; /* request instruction poisoning */
acc = &spec->spec[spec->len - 1];
t = btf__type_by_id(spec->btf, acc->type_id);
/* a[n] accessor needs special handling */
if (!acc->name) {
if (relo->kind == BPF_FIELD_BYTE_OFFSET) {
*val = spec->bit_offset / 8;
/* remember field size for load/store mem size */
sz = btf__resolve_size(spec->btf, acc->type_id);
if (sz < 0)
return -EINVAL;
*field_sz = sz;
*type_id = acc->type_id;
} else if (relo->kind == BPF_FIELD_BYTE_SIZE) {
sz = btf__resolve_size(spec->btf, acc->type_id);
if (sz < 0)
return -EINVAL;
*val = sz;
} else {
pr_warn("prog '%s': relo %d at insn #%d can't be applied to array access\n",
prog->name, relo->kind, relo->insn_off / 8);
return -EINVAL;
}
if (validate)
*validate = true;
return 0;
}
m = btf_members(t) + acc->idx;
mt = skip_mods_and_typedefs(spec->btf, m->type, &field_type_id);
bit_off = spec->bit_offset;
bit_sz = btf_member_bitfield_size(t, acc->idx);
bitfield = bit_sz > 0;
if (bitfield) {
byte_sz = mt->size;
byte_off = bit_off / 8 / byte_sz * byte_sz;
/* figure out smallest int size necessary for bitfield load */
while (bit_off + bit_sz - byte_off * 8 > byte_sz * 8) {
if (byte_sz >= 8) {
/* bitfield can't be read with 64-bit read */
pr_warn("prog '%s': relo %d at insn #%d can't be satisfied for bitfield\n",
prog->name, relo->kind, relo->insn_off / 8);
return -E2BIG;
}
byte_sz *= 2;
byte_off = bit_off / 8 / byte_sz * byte_sz;
}
} else {
sz = btf__resolve_size(spec->btf, field_type_id);
if (sz < 0)
return -EINVAL;
byte_sz = sz;
byte_off = spec->bit_offset / 8;
bit_sz = byte_sz * 8;
}
/* for bitfields, all the relocatable aspects are ambiguous and we
* might disagree with compiler, so turn off validation of expected
* value, except for signedness
*/
if (validate)
*validate = !bitfield;
switch (relo->kind) {
case BPF_FIELD_BYTE_OFFSET:
*val = byte_off;
if (!bitfield) {
*field_sz = byte_sz;
*type_id = field_type_id;
}
break;
case BPF_FIELD_BYTE_SIZE:
*val = byte_sz;
break;
case BPF_FIELD_SIGNED:
/* enums will be assumed unsigned */
*val = btf_is_enum(mt) ||
(btf_int_encoding(mt) & BTF_INT_SIGNED);
if (validate)
*validate = true; /* signedness is never ambiguous */
break;
case BPF_FIELD_LSHIFT_U64:
#if __BYTE_ORDER == __LITTLE_ENDIAN
*val = 64 - (bit_off + bit_sz - byte_off * 8);
#else
*val = (8 - byte_sz) * 8 + (bit_off - byte_off * 8);
#endif
break;
case BPF_FIELD_RSHIFT_U64:
*val = 64 - bit_sz;
if (validate)
*validate = true; /* right shift is never ambiguous */
break;
case BPF_FIELD_EXISTS:
default:
return -EOPNOTSUPP;
}
return 0;
}
static int bpf_core_calc_type_relo(const struct bpf_core_relo *relo,
const struct bpf_core_spec *spec,
__u32 *val)
{
__s64 sz;
/* type-based relos return zero when target type is not found */
if (!spec) {
*val = 0;
return 0;
}
switch (relo->kind) {
case BPF_TYPE_ID_TARGET:
*val = spec->root_type_id;
break;
case BPF_TYPE_EXISTS:
*val = 1;
break;
case BPF_TYPE_SIZE:
sz = btf__resolve_size(spec->btf, spec->root_type_id);
if (sz < 0)
return -EINVAL;
*val = sz;
break;
case BPF_TYPE_ID_LOCAL:
/* BPF_TYPE_ID_LOCAL is handled specially and shouldn't get here */
default:
return -EOPNOTSUPP;
}
return 0;
}
static int bpf_core_calc_enumval_relo(const struct bpf_core_relo *relo,
const struct bpf_core_spec *spec,
__u32 *val)
{
const struct btf_type *t;
const struct btf_enum *e;
switch (relo->kind) {
case BPF_ENUMVAL_EXISTS:
*val = spec ? 1 : 0;
break;
case BPF_ENUMVAL_VALUE:
if (!spec)
return -EUCLEAN; /* request instruction poisoning */
t = btf__type_by_id(spec->btf, spec->spec[0].type_id);
e = btf_enum(t) + spec->spec[0].idx;
*val = e->val;
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
struct bpf_core_relo_res
{
/* expected value in the instruction, unless validate == false */
__u32 orig_val;
/* new value that needs to be patched up to */
__u32 new_val;
/* relocation unsuccessful, poison instruction, but don't fail load */
bool poison;
/* some relocations can't be validated against orig_val */
bool validate;
/* for field byte offset relocations or the forms:
* *(T *)(rX + <off>) = rY
* rX = *(T *)(rY + <off>),
* we remember original and resolved field size to adjust direct
* memory loads of pointers and integers; this is necessary for 32-bit
* host kernel architectures, but also allows to automatically
* relocate fields that were resized from, e.g., u32 to u64, etc.
*/
bool fail_memsz_adjust;
__u32 orig_sz;
__u32 orig_type_id;
__u32 new_sz;
__u32 new_type_id;
};
/* Calculate original and target relocation values, given local and target
* specs and relocation kind. These values are calculated for each candidate.
* If there are multiple candidates, resulting values should all be consistent
* with each other. Otherwise, libbpf will refuse to proceed due to ambiguity.
* If instruction has to be poisoned, *poison will be set to true.
*/
static int bpf_core_calc_relo(const struct bpf_program *prog,
const struct bpf_core_relo *relo,
int relo_idx,
const struct bpf_core_spec *local_spec,
const struct bpf_core_spec *targ_spec,
struct bpf_core_relo_res *res)
{
int err = -EOPNOTSUPP;
res->orig_val = 0;
res->new_val = 0;
res->poison = false;
res->validate = true;
res->fail_memsz_adjust = false;
res->orig_sz = res->new_sz = 0;
res->orig_type_id = res->new_type_id = 0;
if (core_relo_is_field_based(relo->kind)) {
err = bpf_core_calc_field_relo(prog, relo, local_spec,
&res->orig_val, &res->orig_sz,
&res->orig_type_id, &res->validate);
err = err ?: bpf_core_calc_field_relo(prog, relo, targ_spec,
&res->new_val, &res->new_sz,
&res->new_type_id, NULL);
if (err)
goto done;
/* Validate if it's safe to adjust load/store memory size.
* Adjustments are performed only if original and new memory
* sizes differ.
*/
res->fail_memsz_adjust = false;
if (res->orig_sz != res->new_sz) {
const struct btf_type *orig_t, *new_t;
orig_t = btf__type_by_id(local_spec->btf, res->orig_type_id);
new_t = btf__type_by_id(targ_spec->btf, res->new_type_id);
/* There are two use cases in which it's safe to
* adjust load/store's mem size:
* - reading a 32-bit kernel pointer, while on BPF
* size pointers are always 64-bit; in this case
* it's safe to "downsize" instruction size due to
* pointer being treated as unsigned integer with
* zero-extended upper 32-bits;
* - reading unsigned integers, again due to
* zero-extension is preserving the value correctly.
*
* In all other cases it's incorrect to attempt to
* load/store field because read value will be
* incorrect, so we poison relocated instruction.
*/
if (btf_is_ptr(orig_t) && btf_is_ptr(new_t))
goto done;
if (btf_is_int(orig_t) && btf_is_int(new_t) &&
btf_int_encoding(orig_t) != BTF_INT_SIGNED &&
btf_int_encoding(new_t) != BTF_INT_SIGNED)
goto done;
/* mark as invalid mem size adjustment, but this will
* only be checked for LDX/STX/ST insns
*/
res->fail_memsz_adjust = true;
}
} else if (core_relo_is_type_based(relo->kind)) {
err = bpf_core_calc_type_relo(relo, local_spec, &res->orig_val);
err = err ?: bpf_core_calc_type_relo(relo, targ_spec, &res->new_val);
} else if (core_relo_is_enumval_based(relo->kind)) {
err = bpf_core_calc_enumval_relo(relo, local_spec, &res->orig_val);
err = err ?: bpf_core_calc_enumval_relo(relo, targ_spec, &res->new_val);
}
done:
if (err == -EUCLEAN) {
/* EUCLEAN is used to signal instruction poisoning request */
res->poison = true;
err = 0;
} else if (err == -EOPNOTSUPP) {
/* EOPNOTSUPP means unknown/unsupported relocation */
pr_warn("prog '%s': relo #%d: unrecognized CO-RE relocation %s (%d) at insn #%d\n",
prog->name, relo_idx, core_relo_kind_str(relo->kind),
relo->kind, relo->insn_off / 8);
}
return err;
}
/*
* Turn instruction for which CO_RE relocation failed into invalid one with
* distinct signature.
*/
static void bpf_core_poison_insn(struct bpf_program *prog, int relo_idx,
int insn_idx, struct bpf_insn *insn)
{
pr_debug("prog '%s': relo #%d: substituting insn #%d w/ invalid insn\n",
prog->name, relo_idx, insn_idx);
insn->code = BPF_JMP | BPF_CALL;
insn->dst_reg = 0;
insn->src_reg = 0;
insn->off = 0;
/* if this instruction is reachable (not a dead code),
* verifier will complain with the following message:
* invalid func unknown#195896080
*/
insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */
}
static bool is_ldimm64(struct bpf_insn *insn)
{
return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
}
static int insn_bpf_size_to_bytes(struct bpf_insn *insn)
{
switch (BPF_SIZE(insn->code)) {
case BPF_DW: return 8;
case BPF_W: return 4;
case BPF_H: return 2;
case BPF_B: return 1;
default: return -1;
}
}
static int insn_bytes_to_bpf_size(__u32 sz)
{
switch (sz) {
case 8: return BPF_DW;
case 4: return BPF_W;
case 2: return BPF_H;
case 1: return BPF_B;
default: return -1;
}
}
/*
* Patch relocatable BPF instruction.
*
* Patched value is determined by relocation kind and target specification.
* For existence relocations target spec will be NULL if field/type is not found.
* Expected insn->imm value is determined using relocation kind and local
* spec, and is checked before patching instruction. If actual insn->imm value
* is wrong, bail out with error.
*
* Currently supported classes of BPF instruction are:
* 1. rX = <imm> (assignment with immediate operand);
* 2. rX += <imm> (arithmetic operations with immediate operand);
* 3. rX = <imm64> (load with 64-bit immediate value);
* 4. rX = *(T *)(rY + <off>), where T is one of {u8, u16, u32, u64};
* 5. *(T *)(rX + <off>) = rY, where T is one of {u8, u16, u32, u64};
* 6. *(T *)(rX + <off>) = <imm>, where T is one of {u8, u16, u32, u64}.
*/
static int bpf_core_patch_insn(struct bpf_program *prog,
const struct bpf_core_relo *relo,
int relo_idx,
const struct bpf_core_relo_res *res)
{
__u32 orig_val, new_val;
struct bpf_insn *insn;
int insn_idx;
__u8 class;
if (relo->insn_off % BPF_INSN_SZ)
return -EINVAL;
insn_idx = relo->insn_off / BPF_INSN_SZ;
/* adjust insn_idx from section frame of reference to the local
* program's frame of reference; (sub-)program code is not yet
* relocated, so it's enough to just subtract in-section offset
*/
insn_idx = insn_idx - prog->sec_insn_off;
insn = &prog->insns[insn_idx];
class = BPF_CLASS(insn->code);
if (res->poison) {
poison:
/* poison second part of ldimm64 to avoid confusing error from
* verifier about "unknown opcode 00"
*/
if (is_ldimm64(insn))
bpf_core_poison_insn(prog, relo_idx, insn_idx + 1, insn + 1);
bpf_core_poison_insn(prog, relo_idx, insn_idx, insn);
return 0;
}
orig_val = res->orig_val;
new_val = res->new_val;
switch (class) {
case BPF_ALU:
case BPF_ALU64:
if (BPF_SRC(insn->code) != BPF_K)
return -EINVAL;
if (res->validate && insn->imm != orig_val) {
pr_warn("prog '%s': relo #%d: unexpected insn #%d (ALU/ALU64) value: got %u, exp %u -> %u\n",
prog->name, relo_idx,
insn_idx, insn->imm, orig_val, new_val);
return -EINVAL;
}
orig_val = insn->imm;
insn->imm = new_val;
pr_debug("prog '%s': relo #%d: patched insn #%d (ALU/ALU64) imm %u -> %u\n",
prog->name, relo_idx, insn_idx,
orig_val, new_val);
break;
case BPF_LDX:
case BPF_ST:
case BPF_STX:
if (res->validate && insn->off != orig_val) {
pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDX/ST/STX) value: got %u, exp %u -> %u\n",
prog->name, relo_idx, insn_idx, insn->off, orig_val, new_val);
return -EINVAL;
}
if (new_val > SHRT_MAX) {
pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) value too big: %u\n",
prog->name, relo_idx, insn_idx, new_val);
return -ERANGE;
}
if (res->fail_memsz_adjust) {
pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) accesses field incorrectly. "
"Make sure you are accessing pointers, unsigned integers, or fields of matching type and size.\n",
prog->name, relo_idx, insn_idx);
goto poison;
}
orig_val = insn->off;
insn->off = new_val;
pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) off %u -> %u\n",
prog->name, relo_idx, insn_idx, orig_val, new_val);
if (res->new_sz != res->orig_sz) {
int insn_bytes_sz, insn_bpf_sz;
insn_bytes_sz = insn_bpf_size_to_bytes(insn);
if (insn_bytes_sz != res->orig_sz) {
pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) unexpected mem size: got %d, exp %u\n",
prog->name, relo_idx, insn_idx, insn_bytes_sz, res->orig_sz);
return -EINVAL;
}
insn_bpf_sz = insn_bytes_to_bpf_size(res->new_sz);
if (insn_bpf_sz < 0) {
pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) invalid new mem size: %u\n",
prog->name, relo_idx, insn_idx, res->new_sz);
return -EINVAL;
}
insn->code = BPF_MODE(insn->code) | insn_bpf_sz | BPF_CLASS(insn->code);
pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) mem_sz %u -> %u\n",
prog->name, relo_idx, insn_idx, res->orig_sz, res->new_sz);
}
break;
case BPF_LD: {
__u64 imm;
if (!is_ldimm64(insn) ||
insn[0].src_reg != 0 || insn[0].off != 0 ||
insn_idx + 1 >= prog->insns_cnt ||
insn[1].code != 0 || insn[1].dst_reg != 0 ||
insn[1].src_reg != 0 || insn[1].off != 0) {
pr_warn("prog '%s': relo #%d: insn #%d (LDIMM64) has unexpected form\n",
prog->name, relo_idx, insn_idx);
return -EINVAL;
}
imm = insn[0].imm + ((__u64)insn[1].imm << 32);
if (res->validate && imm != orig_val) {
pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDIMM64) value: got %llu, exp %u -> %u\n",
prog->name, relo_idx,
insn_idx, (unsigned long long)imm,
orig_val, new_val);
return -EINVAL;
}
insn[0].imm = new_val;
insn[1].imm = 0; /* currently only 32-bit values are supported */
pr_debug("prog '%s': relo #%d: patched insn #%d (LDIMM64) imm64 %llu -> %u\n",
prog->name, relo_idx, insn_idx,
(unsigned long long)imm, new_val);
break;
}
default:
pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:0x%x, src:0x%x, dst:0x%x, off:0x%x, imm:0x%x\n",
prog->name, relo_idx, insn_idx, insn->code,
insn->src_reg, insn->dst_reg, insn->off, insn->imm);
return -EINVAL;
}
return 0;
}
/* Output spec definition in the format:
* [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>,
* where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b
*/
static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec)
{
const struct btf_type *t;
const struct btf_enum *e;
const char *s;
__u32 type_id;
int i;
type_id = spec->root_type_id;
t = btf__type_by_id(spec->btf, type_id);
s = btf__name_by_offset(spec->btf, t->name_off);
libbpf_print(level, "[%u] %s %s", type_id, btf_kind_str(t), str_is_empty(s) ? "<anon>" : s);
if (core_relo_is_type_based(spec->relo_kind))
return;
if (core_relo_is_enumval_based(spec->relo_kind)) {
t = skip_mods_and_typedefs(spec->btf, type_id, NULL);
e = btf_enum(t) + spec->raw_spec[0];
s = btf__name_by_offset(spec->btf, e->name_off);
libbpf_print(level, "::%s = %u", s, e->val);
return;
}
if (core_relo_is_field_based(spec->relo_kind)) {
for (i = 0; i < spec->len; i++) {
if (spec->spec[i].name)
libbpf_print(level, ".%s", spec->spec[i].name);
else if (i > 0 || spec->spec[i].idx > 0)
libbpf_print(level, "[%u]", spec->spec[i].idx);
}
libbpf_print(level, " (");
for (i = 0; i < spec->raw_len; i++)
libbpf_print(level, "%s%d", i == 0 ? "" : ":", spec->raw_spec[i]);
if (spec->bit_offset % 8)
libbpf_print(level, " @ offset %u.%u)",
spec->bit_offset / 8, spec->bit_offset % 8);
else
libbpf_print(level, " @ offset %u)", spec->bit_offset / 8);
return;
}
}
static size_t bpf_core_hash_fn(const void *key, void *ctx)
{
return (size_t)key;
}
static bool bpf_core_equal_fn(const void *k1, const void *k2, void *ctx)
{
return k1 == k2;
}
static void *u32_as_hash_key(__u32 x)
{
return (void *)(uintptr_t)x;
}
/*
* CO-RE relocate single instruction.
*
* The outline and important points of the algorithm:
* 1. For given local type, find corresponding candidate target types.
* Candidate type is a type with the same "essential" name, ignoring
* everything after last triple underscore (___). E.g., `sample`,
* `sample___flavor_one`, `sample___flavor_another_one`, are all candidates
* for each other. Names with triple underscore are referred to as
* "flavors" and are useful, among other things, to allow to
* specify/support incompatible variations of the same kernel struct, which
* might differ between different kernel versions and/or build
* configurations.
*
* N.B. Struct "flavors" could be generated by bpftool's BTF-to-C
* converter, when deduplicated BTF of a kernel still contains more than
* one different types with the same name. In that case, ___2, ___3, etc
* are appended starting from second name conflict. But start flavors are
* also useful to be defined "locally", in BPF program, to extract same
* data from incompatible changes between different kernel
* versions/configurations. For instance, to handle field renames between
* kernel versions, one can use two flavors of the struct name with the
* same common name and use conditional relocations to extract that field,
* depending on target kernel version.
* 2. For each candidate type, try to match local specification to this
* candidate target type. Matching involves finding corresponding
* high-level spec accessors, meaning that all named fields should match,
* as well as all array accesses should be within the actual bounds. Also,
* types should be compatible (see bpf_core_fields_are_compat for details).
* 3. It is supported and expected that there might be multiple flavors
* matching the spec. As long as all the specs resolve to the same set of
* offsets across all candidates, there is no error. If there is any
* ambiguity, CO-RE relocation will fail. This is necessary to accomodate
* imprefection of BTF deduplication, which can cause slight duplication of
* the same BTF type, if some directly or indirectly referenced (by
* pointer) type gets resolved to different actual types in different
* object files. If such situation occurs, deduplicated BTF will end up
* with two (or more) structurally identical types, which differ only in
* types they refer to through pointer. This should be OK in most cases and
* is not an error.
* 4. Candidate types search is performed by linearly scanning through all
* types in target BTF. It is anticipated that this is overall more
* efficient memory-wise and not significantly worse (if not better)
* CPU-wise compared to prebuilding a map from all local type names to
* a list of candidate type names. It's also sped up by caching resolved
* list of matching candidates per each local "root" type ID, that has at
* least one bpf_core_relo associated with it. This list is shared
* between multiple relocations for the same type ID and is updated as some
* of the candidates are pruned due to structural incompatibility.
*/
static int bpf_core_apply_relo(struct bpf_program *prog,
const struct bpf_core_relo *relo,
int relo_idx,
const struct btf *local_btf,
const struct btf *targ_btf,
struct hashmap *cand_cache)
{
struct bpf_core_spec local_spec, cand_spec, targ_spec = {};
const void *type_key = u32_as_hash_key(relo->type_id);
struct bpf_core_relo_res cand_res, targ_res;
const struct btf_type *local_type;
const char *local_name;
struct ids_vec *cand_ids;
__u32 local_id, cand_id;
const char *spec_str;
int i, j, err;
local_id = relo->type_id;
local_type = btf__type_by_id(local_btf, local_id);
if (!local_type)
return -EINVAL;
local_name = btf__name_by_offset(local_btf, local_type->name_off);
if (!local_name)
return -EINVAL;
spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
if (str_is_empty(spec_str))
return -EINVAL;
err = bpf_core_parse_spec(local_btf, local_id, spec_str, relo->kind, &local_spec);
if (err) {
pr_warn("prog '%s': relo #%d: parsing [%d] %s %s + %s failed: %d\n",
prog->name, relo_idx, local_id, btf_kind_str(local_type),
str_is_empty(local_name) ? "<anon>" : local_name,
spec_str, err);
return -EINVAL;
}
pr_debug("prog '%s': relo #%d: kind <%s> (%d), spec is ", prog->name,
relo_idx, core_relo_kind_str(relo->kind), relo->kind);
bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec);
libbpf_print(LIBBPF_DEBUG, "\n");
/* TYPE_ID_LOCAL relo is special and doesn't need candidate search */
if (relo->kind == BPF_TYPE_ID_LOCAL) {
targ_res.validate = true;
targ_res.poison = false;
targ_res.orig_val = local_spec.root_type_id;
targ_res.new_val = local_spec.root_type_id;
goto patch_insn;
}
/* libbpf doesn't support candidate search for anonymous types */
if (str_is_empty(spec_str)) {
pr_warn("prog '%s': relo #%d: <%s> (%d) relocation doesn't support anonymous types\n",
prog->name, relo_idx, core_relo_kind_str(relo->kind), relo->kind);
return -EOPNOTSUPP;
}
if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) {
cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf);
if (IS_ERR(cand_ids)) {
pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld",
prog->name, relo_idx, local_id, btf_kind_str(local_type),
local_name, PTR_ERR(cand_ids));
return PTR_ERR(cand_ids);
}
err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL);
if (err) {
bpf_core_free_cands(cand_ids);
return err;
}
}
for (i = 0, j = 0; i < cand_ids->len; i++) {
cand_id = cand_ids->data[i];
err = bpf_core_spec_match(&local_spec, targ_btf, cand_id, &cand_spec);
if (err < 0) {
pr_warn("prog '%s': relo #%d: error matching candidate #%d ",
prog->name, relo_idx, i);
bpf_core_dump_spec(LIBBPF_WARN, &cand_spec);
libbpf_print(LIBBPF_WARN, ": %d\n", err);
return err;
}
pr_debug("prog '%s': relo #%d: %s candidate #%d ", prog->name,
relo_idx, err == 0 ? "non-matching" : "matching", i);
bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec);
libbpf_print(LIBBPF_DEBUG, "\n");
if (err == 0)
continue;
err = bpf_core_calc_relo(prog, relo, relo_idx, &local_spec, &cand_spec, &cand_res);
if (err)
return err;
if (j == 0) {
targ_res = cand_res;
targ_spec = cand_spec;
} else if (cand_spec.bit_offset != targ_spec.bit_offset) {
/* if there are many field relo candidates, they
* should all resolve to the same bit offset
*/
pr_warn("prog '%s': relo #%d: field offset ambiguity: %u != %u\n",
prog->name, relo_idx, cand_spec.bit_offset,
targ_spec.bit_offset);
return -EINVAL;
} else if (cand_res.poison != targ_res.poison || cand_res.new_val != targ_res.new_val) {
/* all candidates should result in the same relocation
* decision and value, otherwise it's dangerous to
* proceed due to ambiguity
*/
pr_warn("prog '%s': relo #%d: relocation decision ambiguity: %s %u != %s %u\n",
prog->name, relo_idx,
cand_res.poison ? "failure" : "success", cand_res.new_val,
targ_res.poison ? "failure" : "success", targ_res.new_val);
return -EINVAL;
}
cand_ids->data[j++] = cand_spec.root_type_id;
}
/*
* For BPF_FIELD_EXISTS relo or when used BPF program has field
* existence checks or kernel version/config checks, it's expected
* that we might not find any candidates. In this case, if field
* wasn't found in any candidate, the list of candidates shouldn't
* change at all, we'll just handle relocating appropriately,
* depending on relo's kind.
*/
if (j > 0)
cand_ids->len = j;
/*
* If no candidates were found, it might be both a programmer error,
* as well as expected case, depending whether instruction w/
* relocation is guarded in some way that makes it unreachable (dead
* code) if relocation can't be resolved. This is handled in
* bpf_core_patch_insn() uniformly by replacing that instruction with
* BPF helper call insn (using invalid helper ID). If that instruction
* is indeed unreachable, then it will be ignored and eliminated by
* verifier. If it was an error, then verifier will complain and point
* to a specific instruction number in its log.
*/
if (j == 0) {
pr_debug("prog '%s': relo #%d: no matching targets found\n",
prog->name, relo_idx);
/* calculate single target relo result explicitly */
err = bpf_core_calc_relo(prog, relo, relo_idx, &local_spec, NULL, &targ_res);
if (err)
return err;
}
patch_insn:
/* bpf_core_patch_insn() should know how to handle missing targ_spec */
err = bpf_core_patch_insn(prog, relo, relo_idx, &targ_res);
if (err) {
pr_warn("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n",
prog->name, relo_idx, relo->insn_off, err);
return -EINVAL;
}
return 0;
}
static int
bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
{
const struct btf_ext_info_sec *sec;
const struct bpf_core_relo *rec;
const struct btf_ext_info *seg;
struct hashmap_entry *entry;
struct hashmap *cand_cache = NULL;
struct bpf_program *prog;
struct btf *targ_btf;
const char *sec_name;
int i, err = 0, insn_idx, sec_idx;
if (obj->btf_ext->core_relo_info.len == 0)
return 0;
if (targ_btf_path)
targ_btf = btf__parse(targ_btf_path, NULL);
else
targ_btf = obj->btf_vmlinux;
if (IS_ERR_OR_NULL(targ_btf)) {
pr_warn("failed to get target BTF: %ld\n", PTR_ERR(targ_btf));
return PTR_ERR(targ_btf);
}
cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL);
if (IS_ERR(cand_cache)) {
err = PTR_ERR(cand_cache);
goto out;
}
seg = &obj->btf_ext->core_relo_info;
for_each_btf_ext_sec(seg, sec) {
sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
if (str_is_empty(sec_name)) {
err = -EINVAL;
goto out;
}
/* bpf_object's ELF is gone by now so it's not easy to find
* section index by section name, but we can find *any*
* bpf_program within desired section name and use it's
* prog->sec_idx to do a proper search by section index and
* instruction offset
*/
prog = NULL;
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
if (strcmp(prog->sec_name, sec_name) == 0)
break;
}
if (!prog) {
pr_warn("sec '%s': failed to find a BPF program\n", sec_name);
return -ENOENT;
}
sec_idx = prog->sec_idx;
pr_debug("sec '%s': found %d CO-RE relocations\n",
sec_name, sec->num_info);
for_each_btf_ext_rec(seg, sec, i, rec) {
insn_idx = rec->insn_off / BPF_INSN_SZ;
prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx);
if (!prog) {
pr_warn("sec '%s': failed to find program at insn #%d for CO-RE offset relocation #%d\n",
sec_name, insn_idx, i);
err = -EINVAL;
goto out;
}
/* no need to apply CO-RE relocation if the program is
* not going to be loaded
*/
if (!prog->load)
continue;
err = bpf_core_apply_relo(prog, rec, i, obj->btf,
targ_btf, cand_cache);
if (err) {
pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
prog->name, i, err);
goto out;
}
}
}
out:
/* obj->btf_vmlinux is freed at the end of object load phase */
if (targ_btf != obj->btf_vmlinux)
btf__free(targ_btf);
if (!IS_ERR_OR_NULL(cand_cache)) {
hashmap__for_each_entry(cand_cache, entry, i) {
bpf_core_free_cands(entry->value);
}
hashmap__free(cand_cache);
}
return err;
}
/* Relocate data references within program code:
* - map references;
* - global variable references;
* - extern references.
*/
static int
bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog)
{
int i;
for (i = 0; i < prog->nr_reloc; i++) {
struct reloc_desc *relo = &prog->reloc_desc[i];
struct bpf_insn *insn = &prog->insns[relo->insn_idx];
struct extern_desc *ext;
switch (relo->type) {
case RELO_LD64:
insn[0].src_reg = BPF_PSEUDO_MAP_FD;
insn[0].imm = obj->maps[relo->map_idx].fd;
relo->processed = true;
break;
case RELO_DATA:
insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
insn[1].imm = insn[0].imm + relo->sym_off;
insn[0].imm = obj->maps[relo->map_idx].fd;
relo->processed = true;
break;
case RELO_EXTERN:
ext = &obj->externs[relo->sym_off];
if (ext->type == EXT_KCFG) {
insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
insn[0].imm = obj->maps[obj->kconfig_map_idx].fd;
insn[1].imm = ext->kcfg.data_off;
} else /* EXT_KSYM */ {
if (ext->ksym.type_id) { /* typed ksyms */
insn[0].src_reg = BPF_PSEUDO_BTF_ID;
insn[0].imm = ext->ksym.vmlinux_btf_id;
} else { /* typeless ksyms */
insn[0].imm = (__u32)ext->ksym.addr;
insn[1].imm = ext->ksym.addr >> 32;
}
}
relo->processed = true;
break;
case RELO_CALL:
/* will be handled as a follow up pass */
break;
default:
pr_warn("prog '%s': relo #%d: bad relo type %d\n",
prog->name, i, relo->type);
return -EINVAL;
}
}
return 0;
}
static int adjust_prog_btf_ext_info(const struct bpf_object *obj,
const struct bpf_program *prog,
const struct btf_ext_info *ext_info,
void **prog_info, __u32 *prog_rec_cnt,
__u32 *prog_rec_sz)
{
void *copy_start = NULL, *copy_end = NULL;
void *rec, *rec_end, *new_prog_info;
const struct btf_ext_info_sec *sec;
size_t old_sz, new_sz;
const char *sec_name;
int i, off_adj;
for_each_btf_ext_sec(ext_info, sec) {
sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
if (!sec_name)
return -EINVAL;
if (strcmp(sec_name, prog->sec_name) != 0)
continue;
for_each_btf_ext_rec(ext_info, sec, i, rec) {
__u32 insn_off = *(__u32 *)rec / BPF_INSN_SZ;
if (insn_off < prog->sec_insn_off)
continue;
if (insn_off >= prog->sec_insn_off + prog->sec_insn_cnt)
break;
if (!copy_start)
copy_start = rec;
copy_end = rec + ext_info->rec_size;
}
if (!copy_start)
return -ENOENT;
/* append func/line info of a given (sub-)program to the main
* program func/line info
*/
old_sz = (size_t)(*prog_rec_cnt) * ext_info->rec_size;
new_sz = old_sz + (copy_end - copy_start);
new_prog_info = realloc(*prog_info, new_sz);
if (!new_prog_info)
return -ENOMEM;
*prog_info = new_prog_info;
*prog_rec_cnt = new_sz / ext_info->rec_size;
memcpy(new_prog_info + old_sz, copy_start, copy_end - copy_start);
/* Kernel instruction offsets are in units of 8-byte
* instructions, while .BTF.ext instruction offsets generated
* by Clang are in units of bytes. So convert Clang offsets
* into kernel offsets and adjust offset according to program
* relocated position.
*/
off_adj = prog->sub_insn_off - prog->sec_insn_off;
rec = new_prog_info + old_sz;
rec_end = new_prog_info + new_sz;
for (; rec < rec_end; rec += ext_info->rec_size) {
__u32 *insn_off = rec;
*insn_off = *insn_off / BPF_INSN_SZ + off_adj;
}
*prog_rec_sz = ext_info->rec_size;
return 0;
}
return -ENOENT;
}
static int
reloc_prog_func_and_line_info(const struct bpf_object *obj,
struct bpf_program *main_prog,
const struct bpf_program *prog)
{
int err;
/* no .BTF.ext relocation if .BTF.ext is missing or kernel doesn't
* supprot func/line info
*/
if (!obj->btf_ext || !kernel_supports(FEAT_BTF_FUNC))
return 0;
/* only attempt func info relocation if main program's func_info
* relocation was successful
*/
if (main_prog != prog && !main_prog->func_info)
goto line_info;
err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->func_info,
&main_prog->func_info,
&main_prog->func_info_cnt,
&main_prog->func_info_rec_size);
if (err) {
if (err != -ENOENT) {
pr_warn("prog '%s': error relocating .BTF.ext function info: %d\n",
prog->name, err);
return err;
}
if (main_prog->func_info) {
/*
* Some info has already been found but has problem
* in the last btf_ext reloc. Must have to error out.
*/
pr_warn("prog '%s': missing .BTF.ext function info.\n", prog->name);
return err;
}
/* Have problem loading the very first info. Ignore the rest. */
pr_warn("prog '%s': missing .BTF.ext function info for the main program, skipping all of .BTF.ext func info.\n",
prog->name);
}
line_info:
/* don't relocate line info if main program's relocation failed */
if (main_prog != prog && !main_prog->line_info)
return 0;
err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->line_info,
&main_prog->line_info,
&main_prog->line_info_cnt,
&main_prog->line_info_rec_size);
if (err) {
if (err != -ENOENT) {
pr_warn("prog '%s': error relocating .BTF.ext line info: %d\n",
prog->name, err);
return err;
}
if (main_prog->line_info) {
/*
* Some info has already been found but has problem
* in the last btf_ext reloc. Must have to error out.
*/
pr_warn("prog '%s': missing .BTF.ext line info.\n", prog->name);
return err;
}
/* Have problem loading the very first info. Ignore the rest. */
pr_warn("prog '%s': missing .BTF.ext line info for the main program, skipping all of .BTF.ext line info.\n",
prog->name);
}
return 0;
}
static int cmp_relo_by_insn_idx(const void *key, const void *elem)
{
size_t insn_idx = *(const size_t *)key;
const struct reloc_desc *relo = elem;
if (insn_idx == relo->insn_idx)
return 0;
return insn_idx < relo->insn_idx ? -1 : 1;
}
static struct reloc_desc *find_prog_insn_relo(const struct bpf_program *prog, size_t insn_idx)
{
return bsearch(&insn_idx, prog->reloc_desc, prog->nr_reloc,
sizeof(*prog->reloc_desc), cmp_relo_by_insn_idx);
}
static int
bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog,
struct bpf_program *prog)
{
size_t sub_insn_idx, insn_idx, new_cnt;
struct bpf_program *subprog;
struct bpf_insn *insns, *insn;
struct reloc_desc *relo;
int err;
err = reloc_prog_func_and_line_info(obj, main_prog, prog);
if (err)
return err;
for (insn_idx = 0; insn_idx < prog->sec_insn_cnt; insn_idx++) {
insn = &main_prog->insns[prog->sub_insn_off + insn_idx];
if (!insn_is_subprog_call(insn))
continue;
relo = find_prog_insn_relo(prog, insn_idx);
if (relo && relo->type != RELO_CALL) {
pr_warn("prog '%s': unexpected relo for insn #%zu, type %d\n",
prog->name, insn_idx, relo->type);
return -LIBBPF_ERRNO__RELOC;
}
if (relo) {
/* sub-program instruction index is a combination of
* an offset of a symbol pointed to by relocation and
* call instruction's imm field; for global functions,
* call always has imm = -1, but for static functions
* relocation is against STT_SECTION and insn->imm
* points to a start of a static function
*/
sub_insn_idx = relo->sym_off / BPF_INSN_SZ + insn->imm + 1;
} else {
/* if subprogram call is to a static function within
* the same ELF section, there won't be any relocation
* emitted, but it also means there is no additional
* offset necessary, insns->imm is relative to
* instruction's original position within the section
*/
sub_insn_idx = prog->sec_insn_off + insn_idx + insn->imm + 1;
}
/* we enforce that sub-programs should be in .text section */
subprog = find_prog_by_sec_insn(obj, obj->efile.text_shndx, sub_insn_idx);
if (!subprog) {
pr_warn("prog '%s': no .text section found yet sub-program call exists\n",
prog->name);
return -LIBBPF_ERRNO__RELOC;
}
/* if it's the first call instruction calling into this
* subprogram (meaning this subprog hasn't been processed
* yet) within the context of current main program:
* - append it at the end of main program's instructions blog;
* - process is recursively, while current program is put on hold;
* - if that subprogram calls some other not yet processes
* subprogram, same thing will happen recursively until
* there are no more unprocesses subprograms left to append
* and relocate.
*/
if (subprog->sub_insn_off == 0) {
subprog->sub_insn_off = main_prog->insns_cnt;
new_cnt = main_prog->insns_cnt + subprog->insns_cnt;
insns = libbpf_reallocarray(main_prog->insns, new_cnt, sizeof(*insns));
if (!insns) {
pr_warn("prog '%s': failed to realloc prog code\n", main_prog->name);
return -ENOMEM;
}
main_prog->insns = insns;
main_prog->insns_cnt = new_cnt;
memcpy(main_prog->insns + subprog->sub_insn_off, subprog->insns,
subprog->insns_cnt * sizeof(*insns));
pr_debug("prog '%s': added %zu insns from sub-prog '%s'\n",
main_prog->name, subprog->insns_cnt, subprog->name);
err = bpf_object__reloc_code(obj, main_prog, subprog);
if (err)
return err;
}
/* main_prog->insns memory could have been re-allocated, so
* calculate pointer again
*/
insn = &main_prog->insns[prog->sub_insn_off + insn_idx];
/* calculate correct instruction position within current main
* prog; each main prog can have a different set of
* subprograms appended (potentially in different order as
* well), so position of any subprog can be different for
* different main programs */
insn->imm = subprog->sub_insn_off - (prog->sub_insn_off + insn_idx) - 1;
if (relo)
relo->processed = true;
pr_debug("prog '%s': insn #%zu relocated, imm %d points to subprog '%s' (now at %zu offset)\n",
prog->name, insn_idx, insn->imm, subprog->name, subprog->sub_insn_off);
}
return 0;
}
/*
* Relocate sub-program calls.
*
* Algorithm operates as follows. Each entry-point BPF program (referred to as
* main prog) is processed separately. For each subprog (non-entry functions,
* that can be called from either entry progs or other subprogs) gets their
* sub_insn_off reset to zero. This serves as indicator that this subprogram
* hasn't been yet appended and relocated within current main prog. Once its
* relocated, sub_insn_off will point at the position within current main prog
* where given subprog was appended. This will further be used to relocate all
* the call instructions jumping into this subprog.
*
* We start with main program and process all call instructions. If the call
* is into a subprog that hasn't been processed (i.e., subprog->sub_insn_off
* is zero), subprog instructions are appended at the end of main program's
* instruction array. Then main program is "put on hold" while we recursively
* process newly appended subprogram. If that subprogram calls into another
* subprogram that hasn't been appended, new subprogram is appended again to
* the *main* prog's instructions (subprog's instructions are always left
* untouched, as they need to be in unmodified state for subsequent main progs
* and subprog instructions are always sent only as part of a main prog) and
* the process continues recursively. Once all the subprogs called from a main
* prog or any of its subprogs are appended (and relocated), all their
* positions within finalized instructions array are known, so it's easy to
* rewrite call instructions with correct relative offsets, corresponding to
* desired target subprog.
*
* Its important to realize that some subprogs might not be called from some
* main prog and any of its called/used subprogs. Those will keep their
* subprog->sub_insn_off as zero at all times and won't be appended to current
* main prog and won't be relocated within the context of current main prog.
* They might still be used from other main progs later.
*
* Visually this process can be shown as below. Suppose we have two main
* programs mainA and mainB and BPF object contains three subprogs: subA,
* subB, and subC. mainA calls only subA, mainB calls only subC, but subA and
* subC both call subB:
*
* +--------+ +-------+
* | v v |
* +--+---+ +--+-+-+ +---+--+
* | subA | | subB | | subC |
* +--+---+ +------+ +---+--+
* ^ ^
* | |
* +---+-------+ +------+----+
* | mainA | | mainB |
* +-----------+ +-----------+
*
* We'll start relocating mainA, will find subA, append it and start
* processing sub A recursively:
*
* +-----------+------+
* | mainA | subA |
* +-----------+------+
*
* At this point we notice that subB is used from subA, so we append it and
* relocate (there are no further subcalls from subB):
*
* +-----------+------+------+
* | mainA | subA | subB |
* +-----------+------+------+
*
* At this point, we relocate subA calls, then go one level up and finish with
* relocatin mainA calls. mainA is done.
*
* For mainB process is similar but results in different order. We start with
* mainB and skip subA and subB, as mainB never calls them (at least
* directly), but we see subC is needed, so we append and start processing it:
*
* +-----------+------+
* | mainB | subC |
* +-----------+------+
* Now we see subC needs subB, so we go back to it, append and relocate it:
*
* +-----------+------+------+
* | mainB | subC | subB |
* +-----------+------+------+
*
* At this point we unwind recursion, relocate calls in subC, then in mainB.
*/
static int
bpf_object__relocate_calls(struct bpf_object *obj, struct bpf_program *prog)
{
struct bpf_program *subprog;
int i, j, err;
/* mark all subprogs as not relocated (yet) within the context of
* current main program
*/
for (i = 0; i < obj->nr_programs; i++) {
subprog = &obj->programs[i];
if (!prog_is_subprog(obj, subprog))
continue;
subprog->sub_insn_off = 0;
for (j = 0; j < subprog->nr_reloc; j++)
if (subprog->reloc_desc[j].type == RELO_CALL)
subprog->reloc_desc[j].processed = false;
}
err = bpf_object__reloc_code(obj, prog, prog);
if (err)
return err;
return 0;
}
static int
bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
{
struct bpf_program *prog;
size_t i;
int err;
if (obj->btf_ext) {
err = bpf_object__relocate_core(obj, targ_btf_path);
if (err) {
pr_warn("failed to perform CO-RE relocations: %d\n",
err);
return err;
}
}
/* relocate data references first for all programs and sub-programs,
* as they don't change relative to code locations, so subsequent
* subprogram processing won't need to re-calculate any of them
*/
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
err = bpf_object__relocate_data(obj, prog);
if (err) {
pr_warn("prog '%s': failed to relocate data references: %d\n",
prog->name, err);
return err;
}
}
/* now relocate subprogram calls and append used subprograms to main
* programs; each copy of subprogram code needs to be relocated
* differently for each main program, because its code location might
* have changed
*/
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
/* sub-program's sub-calls are relocated within the context of
* its main program only
*/
if (prog_is_subprog(obj, prog))
continue;
err = bpf_object__relocate_calls(obj, prog);
if (err) {
pr_warn("prog '%s': failed to relocate calls: %d\n",
prog->name, err);
return err;
}
}
/* free up relocation descriptors */
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
zfree(&prog->reloc_desc);
prog->nr_reloc = 0;
}
return 0;
}
static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
GElf_Shdr *shdr, Elf_Data *data);
static int bpf_object__collect_map_relos(struct bpf_object *obj,
GElf_Shdr *shdr, Elf_Data *data)
{
const int bpf_ptr_sz = 8, host_ptr_sz = sizeof(void *);
int i, j, nrels, new_sz;
const struct btf_var_secinfo *vi = NULL;
const struct btf_type *sec, *var, *def;
struct bpf_map *map = NULL, *targ_map;
const struct btf_member *member;
const char *name, *mname;
Elf_Data *symbols;
unsigned int moff;
GElf_Sym sym;
GElf_Rel rel;
void *tmp;
if (!obj->efile.btf_maps_sec_btf_id || !obj->btf)
return -EINVAL;
sec = btf__type_by_id(obj->btf, obj->efile.btf_maps_sec_btf_id);
if (!sec)
return -EINVAL;
symbols = obj->efile.symbols;
nrels = shdr->sh_size / shdr->sh_entsize;
for (i = 0; i < nrels; i++) {
if (!gelf_getrel(data, i, &rel)) {
pr_warn(".maps relo #%d: failed to get ELF relo\n", i);
return -LIBBPF_ERRNO__FORMAT;
}
if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
pr_warn(".maps relo #%d: symbol %zx not found\n",
i, (size_t)GELF_R_SYM(rel.r_info));
return -LIBBPF_ERRNO__FORMAT;
}
name = elf_sym_str(obj, sym.st_name) ?: "<?>";
if (sym.st_shndx != obj->efile.btf_maps_shndx) {
pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n",
i, name);
return -LIBBPF_ERRNO__RELOC;
}
pr_debug(".maps relo #%d: for %zd value %zd rel.r_offset %zu name %d ('%s')\n",
i, (ssize_t)(rel.r_info >> 32), (size_t)sym.st_value,
(size_t)rel.r_offset, sym.st_name, name);
for (j = 0; j < obj->nr_maps; j++) {
map = &obj->maps[j];
if (map->sec_idx != obj->efile.btf_maps_shndx)
continue;
vi = btf_var_secinfos(sec) + map->btf_var_idx;
if (vi->offset <= rel.r_offset &&
rel.r_offset + bpf_ptr_sz <= vi->offset + vi->size)
break;
}
if (j == obj->nr_maps) {
pr_warn(".maps relo #%d: cannot find map '%s' at rel.r_offset %zu\n",
i, name, (size_t)rel.r_offset);
return -EINVAL;
}
if (!bpf_map_type__is_map_in_map(map->def.type))
return -EINVAL;
if (map->def.type == BPF_MAP_TYPE_HASH_OF_MAPS &&
map->def.key_size != sizeof(int)) {
pr_warn(".maps relo #%d: hash-of-maps '%s' should have key size %zu.\n",
i, map->name, sizeof(int));
return -EINVAL;
}
targ_map = bpf_object__find_map_by_name(obj, name);
if (!targ_map)
return -ESRCH;
var = btf__type_by_id(obj->btf, vi->type);
def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
if (btf_vlen(def) == 0)
return -EINVAL;
member = btf_members(def) + btf_vlen(def) - 1;
mname = btf__name_by_offset(obj->btf, member->name_off);
if (strcmp(mname, "values"))
return -EINVAL;
moff = btf_member_bit_offset(def, btf_vlen(def) - 1) / 8;
if (rel.r_offset - vi->offset < moff)
return -EINVAL;
moff = rel.r_offset - vi->offset - moff;
/* here we use BPF pointer size, which is always 64 bit, as we
* are parsing ELF that was built for BPF target
*/
if (moff % bpf_ptr_sz)
return -EINVAL;
moff /= bpf_ptr_sz;
if (moff >= map->init_slots_sz) {
new_sz = moff + 1;
tmp = libbpf_reallocarray(map->init_slots, new_sz, host_ptr_sz);
if (!tmp)
return -ENOMEM;
map->init_slots = tmp;
memset(map->init_slots + map->init_slots_sz, 0,
(new_sz - map->init_slots_sz) * host_ptr_sz);
map->init_slots_sz = new_sz;
}
map->init_slots[moff] = targ_map;
pr_debug(".maps relo #%d: map '%s' slot [%d] points to map '%s'\n",
i, map->name, moff, name);
}
return 0;
}
static int cmp_relocs(const void *_a, const void *_b)
{
const struct reloc_desc *a = _a;
const struct reloc_desc *b = _b;
if (a->insn_idx != b->insn_idx)
return a->insn_idx < b->insn_idx ? -1 : 1;
/* no two relocations should have the same insn_idx, but ... */
if (a->type != b->type)
return a->type < b->type ? -1 : 1;
return 0;
}
static int bpf_object__collect_relos(struct bpf_object *obj)
{
int i, err;
for (i = 0; i < obj->efile.nr_reloc_sects; i++) {
GElf_Shdr *shdr = &obj->efile.reloc_sects[i].shdr;
Elf_Data *data = obj->efile.reloc_sects[i].data;
int idx = shdr->sh_info;
if (shdr->sh_type != SHT_REL) {
pr_warn("internal error at %d\n", __LINE__);
return -LIBBPF_ERRNO__INTERNAL;
}
if (idx == obj->efile.st_ops_shndx)
err = bpf_object__collect_st_ops_relos(obj, shdr, data);
else if (idx == obj->efile.btf_maps_shndx)
err = bpf_object__collect_map_relos(obj, shdr, data);
else
err = bpf_object__collect_prog_relos(obj, shdr, data);
if (err)
return err;
}
for (i = 0; i < obj->nr_programs; i++) {
struct bpf_program *p = &obj->programs[i];
if (!p->nr_reloc)
continue;
qsort(p->reloc_desc, p->nr_reloc, sizeof(*p->reloc_desc), cmp_relocs);
}
return 0;
}
static bool insn_is_helper_call(struct bpf_insn *insn, enum bpf_func_id *func_id)
{
if (BPF_CLASS(insn->code) == BPF_JMP &&
BPF_OP(insn->code) == BPF_CALL &&
BPF_SRC(insn->code) == BPF_K &&
insn->src_reg == 0 &&
insn->dst_reg == 0) {
*func_id = insn->imm;
return true;
}
return false;
}
static int bpf_object__sanitize_prog(struct bpf_object* obj, struct bpf_program *prog)
{
struct bpf_insn *insn = prog->insns;
enum bpf_func_id func_id;
int i;
for (i = 0; i < prog->insns_cnt; i++, insn++) {
if (!insn_is_helper_call(insn, &func_id))
continue;
/* on kernels that don't yet support
* bpf_probe_read_{kernel,user}[_str] helpers, fall back
* to bpf_probe_read() which works well for old kernels
*/
switch (func_id) {
case BPF_FUNC_probe_read_kernel:
case BPF_FUNC_probe_read_user:
if (!kernel_supports(FEAT_PROBE_READ_KERN))
insn->imm = BPF_FUNC_probe_read;
break;
case BPF_FUNC_probe_read_kernel_str:
case BPF_FUNC_probe_read_user_str:
if (!kernel_supports(FEAT_PROBE_READ_KERN))
insn->imm = BPF_FUNC_probe_read_str;
break;
default:
break;
}
}
return 0;
}
static int
load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
char *license, __u32 kern_version, int *pfd)
{
struct bpf_load_program_attr load_attr;
char *cp, errmsg[STRERR_BUFSIZE];
size_t log_buf_size = 0;
char *log_buf = NULL;
int btf_fd, ret;
if (!insns || !insns_cnt)
return -EINVAL;
memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
load_attr.prog_type = prog->type;
/* old kernels might not support specifying expected_attach_type */
if (!kernel_supports(FEAT_EXP_ATTACH_TYPE) && prog->sec_def &&
prog->sec_def->is_exp_attach_type_optional)
load_attr.expected_attach_type = 0;
else
load_attr.expected_attach_type = prog->expected_attach_type;
if (kernel_supports(FEAT_PROG_NAME))
load_attr.name = prog->name;
load_attr.insns = insns;
load_attr.insns_cnt = insns_cnt;
load_attr.license = license;
if (prog->type == BPF_PROG_TYPE_STRUCT_OPS ||
prog->type == BPF_PROG_TYPE_LSM) {
load_attr.attach_btf_id = prog->attach_btf_id;
} else if (prog->type == BPF_PROG_TYPE_TRACING ||
prog->type == BPF_PROG_TYPE_EXT) {
load_attr.attach_prog_fd = prog->attach_prog_fd;
load_attr.attach_btf_id = prog->attach_btf_id;
} else {
load_attr.kern_version = kern_version;
load_attr.prog_ifindex = prog->prog_ifindex;
}
/* specify func_info/line_info only if kernel supports them */
btf_fd = bpf_object__btf_fd(prog->obj);
if (btf_fd >= 0 && kernel_supports(FEAT_BTF_FUNC)) {
load_attr.prog_btf_fd = btf_fd;
load_attr.func_info = prog->func_info;
load_attr.func_info_rec_size = prog->func_info_rec_size;
load_attr.func_info_cnt = prog->func_info_cnt;
load_attr.line_info = prog->line_info;
load_attr.line_info_rec_size = prog->line_info_rec_size;
load_attr.line_info_cnt = prog->line_info_cnt;
}
load_attr.log_level = prog->log_level;
load_attr.prog_flags = prog->prog_flags;
retry_load:
if (log_buf_size) {
log_buf = malloc(log_buf_size);
if (!log_buf)
return -ENOMEM;
*log_buf = 0;
}
ret = bpf_load_program_xattr(&load_attr, log_buf, log_buf_size);
if (ret >= 0) {
if (log_buf && load_attr.log_level)
pr_debug("verifier log:\n%s", log_buf);
if (prog->obj->rodata_map_idx >= 0 &&
kernel_supports(FEAT_PROG_BIND_MAP)) {
struct bpf_map *rodata_map =
&prog->obj->maps[prog->obj->rodata_map_idx];
if (bpf_prog_bind_map(ret, bpf_map__fd(rodata_map), NULL)) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("prog '%s': failed to bind .rodata map: %s\n",
prog->name, cp);
/* Don't fail hard if can't bind rodata. */
}
}
*pfd = ret;
ret = 0;
goto out;
}
if (!log_buf || errno == ENOSPC) {
log_buf_size = max((size_t)BPF_LOG_BUF_SIZE,
log_buf_size << 1);
free(log_buf);
goto retry_load;
}
ret = errno ? -errno : -LIBBPF_ERRNO__LOAD;
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("load bpf program failed: %s\n", cp);
pr_perm_msg(ret);
if (log_buf && log_buf[0] != '\0') {
ret = -LIBBPF_ERRNO__VERIFY;
pr_warn("-- BEGIN DUMP LOG ---\n");
pr_warn("\n%s\n", log_buf);
pr_warn("-- END LOG --\n");
} else if (load_attr.insns_cnt >= BPF_MAXINSNS) {
pr_warn("Program too large (%zu insns), at most %d insns\n",
load_attr.insns_cnt, BPF_MAXINSNS);
ret = -LIBBPF_ERRNO__PROG2BIG;
} else if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
/* Wrong program type? */
int fd;
load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
load_attr.expected_attach_type = 0;
fd = bpf_load_program_xattr(&load_attr, NULL, 0);
if (fd >= 0) {
close(fd);
ret = -LIBBPF_ERRNO__PROGTYPE;
goto out;
}
}
out:
free(log_buf);
return ret;
}
static int libbpf_find_attach_btf_id(struct bpf_program *prog);
int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver)
{
int err = 0, fd, i, btf_id;
if (prog->obj->loaded) {
pr_warn("prog '%s': can't load after object was loaded\n", prog->name);
return -EINVAL;
}
if ((prog->type == BPF_PROG_TYPE_TRACING ||
prog->type == BPF_PROG_TYPE_LSM ||
prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) {
btf_id = libbpf_find_attach_btf_id(prog);
if (btf_id <= 0)
return btf_id;
prog->attach_btf_id = btf_id;
}
if (prog->instances.nr < 0 || !prog->instances.fds) {
if (prog->preprocessor) {
pr_warn("Internal error: can't load program '%s'\n",
prog->name);
return -LIBBPF_ERRNO__INTERNAL;
}
prog->instances.fds = malloc(sizeof(int));
if (!prog->instances.fds) {
pr_warn("Not enough memory for BPF fds\n");
return -ENOMEM;
}
prog->instances.nr = 1;
prog->instances.fds[0] = -1;
}
if (!prog->preprocessor) {
if (prog->instances.nr != 1) {
pr_warn("prog '%s': inconsistent nr(%d) != 1\n",
prog->name, prog->instances.nr);
}
err = load_program(prog, prog->insns, prog->insns_cnt,
license, kern_ver, &fd);
if (!err)
prog->instances.fds[0] = fd;
goto out;
}
for (i = 0; i < prog->instances.nr; i++) {
struct bpf_prog_prep_result result;
bpf_program_prep_t preprocessor = prog->preprocessor;
memset(&result, 0, sizeof(result));
err = preprocessor(prog, i, prog->insns,
prog->insns_cnt, &result);
if (err) {
pr_warn("Preprocessing the %dth instance of program '%s' failed\n",
i, prog->name);
goto out;
}
if (!result.new_insn_ptr || !result.new_insn_cnt) {
pr_debug("Skip loading the %dth instance of program '%s'\n",
i, prog->name);
prog->instances.fds[i] = -1;
if (result.pfd)
*result.pfd = -1;
continue;
}
err = load_program(prog, result.new_insn_ptr,
result.new_insn_cnt, license, kern_ver, &fd);
if (err) {
pr_warn("Loading the %dth instance of program '%s' failed\n",
i, prog->name);
goto out;
}
if (result.pfd)
*result.pfd = fd;
prog->instances.fds[i] = fd;
}
out:
if (err)
pr_warn("failed to load program '%s'\n", prog->name);
zfree(&prog->insns);
prog->insns_cnt = 0;
return err;
}
static int
bpf_object__load_progs(struct bpf_object *obj, int log_level)
{
struct bpf_program *prog;
size_t i;
int err;
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
err = bpf_object__sanitize_prog(obj, prog);
if (err)
return err;
}
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
if (prog_is_subprog(obj, prog))
continue;
if (!prog->load) {
pr_debug("prog '%s': skipped loading\n", prog->name);
continue;
}
prog->log_level |= log_level;
err = bpf_program__load(prog, obj->license, obj->kern_version);
if (err)
return err;
}
return 0;
}
static const struct bpf_sec_def *find_sec_def(const char *sec_name);
static struct bpf_object *
__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
const struct bpf_object_open_opts *opts)
{
const char *obj_name, *kconfig;
struct bpf_program *prog;
struct bpf_object *obj;
char tmp_name[64];
int err;
if (elf_version(EV_CURRENT) == EV_NONE) {
pr_warn("failed to init libelf for %s\n",
path ? : "(mem buf)");
return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
}
if (!OPTS_VALID(opts, bpf_object_open_opts))
return ERR_PTR(-EINVAL);
obj_name = OPTS_GET(opts, object_name, NULL);
if (obj_buf) {
if (!obj_name) {
snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
(unsigned long)obj_buf,
(unsigned long)obj_buf_sz);
obj_name = tmp_name;
}
path = obj_name;
pr_debug("loading object '%s' from buffer\n", obj_name);
}
obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name);
if (IS_ERR(obj))
return obj;
kconfig = OPTS_GET(opts, kconfig, NULL);
if (kconfig) {
obj->kconfig = strdup(kconfig);
if (!obj->kconfig) {
err = -ENOMEM;
goto out;
}
}
err = bpf_object__elf_init(obj);
err = err ? : bpf_object__check_endianness(obj);
err = err ? : bpf_object__elf_collect(obj);
err = err ? : bpf_object__collect_externs(obj);
err = err ? : bpf_object__finalize_btf(obj);
err = err ? : bpf_object__init_maps(obj, opts);
err = err ? : bpf_object__collect_relos(obj);
if (err)
goto out;
bpf_object__elf_finish(obj);
bpf_object__for_each_program(prog, obj) {
prog->sec_def = find_sec_def(prog->sec_name);
if (!prog->sec_def)
/* couldn't guess, but user might manually specify */
continue;
if (prog->sec_def->is_sleepable)
prog->prog_flags |= BPF_F_SLEEPABLE;
bpf_program__set_type(prog, prog->sec_def->prog_type);
bpf_program__set_expected_attach_type(prog,
prog->sec_def->expected_attach_type);
if (prog->sec_def->prog_type == BPF_PROG_TYPE_TRACING ||
prog->sec_def->prog_type == BPF_PROG_TYPE_EXT)
prog->attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0);
}
return obj;
out:
bpf_object__close(obj);
return ERR_PTR(err);
}
static struct bpf_object *
__bpf_object__open_xattr(struct bpf_object_open_attr *attr, int flags)
{
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
.relaxed_maps = flags & MAPS_RELAX_COMPAT,
);
/* param validation */
if (!attr->file)
return NULL;
pr_debug("loading %s\n", attr->file);
return __bpf_object__open(attr->file, NULL, 0, &opts);
}
struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr)
{
return __bpf_object__open_xattr(attr, 0);
}
struct bpf_object *bpf_object__open(const char *path)
{
struct bpf_object_open_attr attr = {
.file = path,
.prog_type = BPF_PROG_TYPE_UNSPEC,
};
return bpf_object__open_xattr(&attr);
}
struct bpf_object *
bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts)
{
if (!path)
return ERR_PTR(-EINVAL);
pr_debug("loading %s\n", path);
return __bpf_object__open(path, NULL, 0, opts);
}
struct bpf_object *
bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
const struct bpf_object_open_opts *opts)
{
if (!obj_buf || obj_buf_sz == 0)
return ERR_PTR(-EINVAL);
return __bpf_object__open(NULL, obj_buf, obj_buf_sz, opts);
}
struct bpf_object *
bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz,
const char *name)
{
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
.object_name = name,
/* wrong default, but backwards-compatible */
.relaxed_maps = true,
);
/* returning NULL is wrong, but backwards-compatible */
if (!obj_buf || obj_buf_sz == 0)
return NULL;
return bpf_object__open_mem(obj_buf, obj_buf_sz, &opts);
}
int bpf_object__unload(struct bpf_object *obj)
{
size_t i;
if (!obj)
return -EINVAL;
for (i = 0; i < obj->nr_maps; i++) {
zclose(obj->maps[i].fd);
if (obj->maps[i].st_ops)
zfree(&obj->maps[i].st_ops->kern_vdata);
}
for (i = 0; i < obj->nr_programs; i++)
bpf_program__unload(&obj->programs[i]);
return 0;
}
static int bpf_object__sanitize_maps(struct bpf_object *obj)
{
struct bpf_map *m;
bpf_object__for_each_map(m, obj) {
if (!bpf_map__is_internal(m))
continue;
if (!kernel_supports(FEAT_GLOBAL_DATA)) {
pr_warn("kernel doesn't support global data\n");
return -ENOTSUP;
}
if (!kernel_supports(FEAT_ARRAY_MMAP))
m->def.map_flags ^= BPF_F_MMAPABLE;
}
return 0;
}
static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
{
char sym_type, sym_name[500];
unsigned long long sym_addr;
struct extern_desc *ext;
int ret, err = 0;
FILE *f;
f = fopen("/proc/kallsyms", "r");
if (!f) {
err = -errno;
pr_warn("failed to open /proc/kallsyms: %d\n", err);
return err;
}
while (true) {
ret = fscanf(f, "%llx %c %499s%*[^\n]\n",
&sym_addr, &sym_type, sym_name);
if (ret == EOF && feof(f))
break;
if (ret != 3) {
pr_warn("failed to read kallsyms entry: %d\n", ret);
err = -EINVAL;
goto out;
}
ext = find_extern_by_name(obj, sym_name);
if (!ext || ext->type != EXT_KSYM)
continue;
if (ext->is_set && ext->ksym.addr != sym_addr) {
pr_warn("extern (ksym) '%s' resolution is ambiguous: 0x%llx or 0x%llx\n",
sym_name, ext->ksym.addr, sym_addr);
err = -EINVAL;
goto out;
}
if (!ext->is_set) {
ext->is_set = true;
ext->ksym.addr = sym_addr;
pr_debug("extern (ksym) %s=0x%llx\n", sym_name, sym_addr);
}
}
out:
fclose(f);
return err;
}
static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj)
{
struct extern_desc *ext;
int i, id;
for (i = 0; i < obj->nr_extern; i++) {
const struct btf_type *targ_var, *targ_type;
__u32 targ_type_id, local_type_id;
const char *targ_var_name;
int ret;
ext = &obj->externs[i];
if (ext->type != EXT_KSYM || !ext->ksym.type_id)
continue;
id = btf__find_by_name_kind(obj->btf_vmlinux, ext->name,
BTF_KIND_VAR);
if (id <= 0) {
pr_warn("extern (ksym) '%s': failed to find BTF ID in vmlinux BTF.\n",
ext->name);
return -ESRCH;
}
/* find local type_id */
local_type_id = ext->ksym.type_id;
/* find target type_id */
targ_var = btf__type_by_id(obj->btf_vmlinux, id);
targ_var_name = btf__name_by_offset(obj->btf_vmlinux,
targ_var->name_off);
targ_type = skip_mods_and_typedefs(obj->btf_vmlinux,
targ_var->type,
&targ_type_id);
ret = bpf_core_types_are_compat(obj->btf, local_type_id,
obj->btf_vmlinux, targ_type_id);
if (ret <= 0) {
const struct btf_type *local_type;
const char *targ_name, *local_name;
local_type = btf__type_by_id(obj->btf, local_type_id);
local_name = btf__name_by_offset(obj->btf,
local_type->name_off);
targ_name = btf__name_by_offset(obj->btf_vmlinux,
targ_type->name_off);
pr_warn("extern (ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n",
ext->name, local_type_id,
btf_kind_str(local_type), local_name, targ_type_id,
btf_kind_str(targ_type), targ_name);
return -EINVAL;
}
ext->is_set = true;
ext->ksym.vmlinux_btf_id = id;
pr_debug("extern (ksym) '%s': resolved to [%d] %s %s\n",
ext->name, id, btf_kind_str(targ_var), targ_var_name);
}
return 0;
}
static int bpf_object__resolve_externs(struct bpf_object *obj,
const char *extra_kconfig)
{
bool need_config = false, need_kallsyms = false;
bool need_vmlinux_btf = false;
struct extern_desc *ext;
void *kcfg_data = NULL;
int err, i;
if (obj->nr_extern == 0)
return 0;
if (obj->kconfig_map_idx >= 0)
kcfg_data = obj->maps[obj->kconfig_map_idx].mmaped;
for (i = 0; i < obj->nr_extern; i++) {
ext = &obj->externs[i];
if (ext->type == EXT_KCFG &&
strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) {
void *ext_val = kcfg_data + ext->kcfg.data_off;
__u32 kver = get_kernel_version();
if (!kver) {
pr_warn("failed to get kernel version\n");
return -EINVAL;
}
err = set_kcfg_value_num(ext, ext_val, kver);
if (err)
return err;
pr_debug("extern (kcfg) %s=0x%x\n", ext->name, kver);
} else if (ext->type == EXT_KCFG &&
strncmp(ext->name, "CONFIG_", 7) == 0) {
need_config = true;
} else if (ext->type == EXT_KSYM) {
if (ext->ksym.type_id)
need_vmlinux_btf = true;
else
need_kallsyms = true;
} else {
pr_warn("unrecognized extern '%s'\n", ext->name);
return -EINVAL;
}
}
if (need_config && extra_kconfig) {
err = bpf_object__read_kconfig_mem(obj, extra_kconfig, kcfg_data);
if (err)
return -EINVAL;
need_config = false;
for (i = 0; i < obj->nr_extern; i++) {
ext = &obj->externs[i];
if (ext->type == EXT_KCFG && !ext->is_set) {
need_config = true;
break;
}
}
}
if (need_config) {
err = bpf_object__read_kconfig_file(obj, kcfg_data);
if (err)
return -EINVAL;
}
if (need_kallsyms) {
err = bpf_object__read_kallsyms_file(obj);
if (err)
return -EINVAL;
}
if (need_vmlinux_btf) {
err = bpf_object__resolve_ksyms_btf_id(obj);
if (err)
return -EINVAL;
}
for (i = 0; i < obj->nr_extern; i++) {
ext = &obj->externs[i];
if (!ext->is_set && !ext->is_weak) {
pr_warn("extern %s (strong) not resolved\n", ext->name);
return -ESRCH;
} else if (!ext->is_set) {
pr_debug("extern %s (weak) not resolved, defaulting to zero\n",
ext->name);
}
}
return 0;
}
int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
{
struct bpf_object *obj;
int err, i;
if (!attr)
return -EINVAL;
obj = attr->obj;
if (!obj)
return -EINVAL;
if (obj->loaded) {
pr_warn("object '%s': load can't be attempted twice\n", obj->name);
return -EINVAL;
}
err = bpf_object__probe_loading(obj);
err = err ? : bpf_object__load_vmlinux_btf(obj);
err = err ? : bpf_object__resolve_externs(obj, obj->kconfig);
err = err ? : bpf_object__sanitize_and_load_btf(obj);
err = err ? : bpf_object__sanitize_maps(obj);
err = err ? : bpf_object__init_kern_struct_ops_maps(obj);
err = err ? : bpf_object__create_maps(obj);
err = err ? : bpf_object__relocate(obj, attr->target_btf_path);
err = err ? : bpf_object__load_progs(obj, attr->log_level);
btf__free(obj->btf_vmlinux);
obj->btf_vmlinux = NULL;
obj->loaded = true; /* doesn't matter if successfully or not */
if (err)
goto out;
return 0;
out:
/* unpin any maps that were auto-pinned during load */
for (i = 0; i < obj->nr_maps; i++)
if (obj->maps[i].pinned && !obj->maps[i].reused)
bpf_map__unpin(&obj->maps[i], NULL);
bpf_object__unload(obj);
pr_warn("failed to load object '%s'\n", obj->path);
return err;
}
int bpf_object__load(struct bpf_object *obj)
{
struct bpf_object_load_attr attr = {
.obj = obj,
};
return bpf_object__load_xattr(&attr);
}
static int make_parent_dir(const char *path)
{
char *cp, errmsg[STRERR_BUFSIZE];
char *dname, *dir;
int err = 0;
dname = strdup(path);
if (dname == NULL)
return -ENOMEM;
dir = dirname(dname);
if (mkdir(dir, 0700) && errno != EEXIST)
err = -errno;
free(dname);
if (err) {
cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
pr_warn("failed to mkdir %s: %s\n", path, cp);
}
return err;
}
static int check_path(const char *path)
{
char *cp, errmsg[STRERR_BUFSIZE];
struct statfs st_fs;
char *dname, *dir;
int err = 0;
if (path == NULL)
return -EINVAL;
dname = strdup(path);
if (dname == NULL)
return -ENOMEM;
dir = dirname(dname);
if (statfs(dir, &st_fs)) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("failed to statfs %s: %s\n", dir, cp);
err = -errno;
}
free(dname);
if (!err && st_fs.f_type != BPF_FS_MAGIC) {
pr_warn("specified path %s is not on BPF FS\n", path);
err = -EINVAL;
}
return err;
}
int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
int instance)
{
char *cp, errmsg[STRERR_BUFSIZE];
int err;
err = make_parent_dir(path);
if (err)
return err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (instance < 0 || instance >= prog->instances.nr) {
pr_warn("invalid prog instance %d of prog %s (max %d)\n",
instance, prog->name, prog->instances.nr);
return -EINVAL;
}
if (bpf_obj_pin(prog->instances.fds[instance], path)) {
err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("failed to pin program: %s\n", cp);
return err;
}
pr_debug("pinned program '%s'\n", path);
return 0;
}
int bpf_program__unpin_instance(struct bpf_program *prog, const char *path,
int instance)
{
int err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (instance < 0 || instance >= prog->instances.nr) {
pr_warn("invalid prog instance %d of prog %s (max %d)\n",
instance, prog->name, prog->instances.nr);
return -EINVAL;
}
err = unlink(path);
if (err != 0)
return -errno;
pr_debug("unpinned program '%s'\n", path);
return 0;
}
int bpf_program__pin(struct bpf_program *prog, const char *path)
{
int i, err;
err = make_parent_dir(path);
if (err)
return err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (prog->instances.nr <= 0) {
pr_warn("no instances of prog %s to pin\n", prog->name);
return -EINVAL;
}
if (prog->instances.nr == 1) {
/* don't create subdirs when pinning single instance */
return bpf_program__pin_instance(prog, path, 0);
}
for (i = 0; i < prog->instances.nr; i++) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
if (len < 0) {
err = -EINVAL;
goto err_unpin;
} else if (len >= PATH_MAX) {
err = -ENAMETOOLONG;
goto err_unpin;
}
err = bpf_program__pin_instance(prog, buf, i);
if (err)
goto err_unpin;
}
return 0;
err_unpin:
for (i = i - 1; i >= 0; i--) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
if (len < 0)
continue;
else if (len >= PATH_MAX)
continue;
bpf_program__unpin_instance(prog, buf, i);
}
rmdir(path);
return err;
}
int bpf_program__unpin(struct bpf_program *prog, const char *path)
{
int i, err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (prog->instances.nr <= 0) {
pr_warn("no instances of prog %s to pin\n", prog->name);
return -EINVAL;
}
if (prog->instances.nr == 1) {
/* don't create subdirs when pinning single instance */
return bpf_program__unpin_instance(prog, path, 0);
}
for (i = 0; i < prog->instances.nr; i++) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
err = bpf_program__unpin_instance(prog, buf, i);
if (err)
return err;
}
err = rmdir(path);
if (err)
return -errno;
return 0;
}
int bpf_map__pin(struct bpf_map *map, const char *path)
{
char *cp, errmsg[STRERR_BUFSIZE];
int err;
if (map == NULL) {
pr_warn("invalid map pointer\n");
return -EINVAL;
}
if (map->pin_path) {
if (path && strcmp(path, map->pin_path)) {
pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
bpf_map__name(map), map->pin_path, path);
return -EINVAL;
} else if (map->pinned) {
pr_debug("map '%s' already pinned at '%s'; not re-pinning\n",
bpf_map__name(map), map->pin_path);
return 0;
}
} else {
if (!path) {
pr_warn("missing a path to pin map '%s' at\n",
bpf_map__name(map));
return -EINVAL;
} else if (map->pinned) {
pr_warn("map '%s' already pinned\n", bpf_map__name(map));
return -EEXIST;
}
map->pin_path = strdup(path);
if (!map->pin_path) {
err = -errno;
goto out_err;
}
}
err = make_parent_dir(map->pin_path);
if (err)
return err;
err = check_path(map->pin_path);
if (err)
return err;
if (bpf_obj_pin(map->fd, map->pin_path)) {
err = -errno;
goto out_err;
}
map->pinned = true;
pr_debug("pinned map '%s'\n", map->pin_path);
return 0;
out_err:
cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
pr_warn("failed to pin map: %s\n", cp);
return err;
}
int bpf_map__unpin(struct bpf_map *map, const char *path)
{
int err;
if (map == NULL) {
pr_warn("invalid map pointer\n");
return -EINVAL;
}
if (map->pin_path) {
if (path && strcmp(path, map->pin_path)) {
pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
bpf_map__name(map), map->pin_path, path);
return -EINVAL;
}
path = map->pin_path;
} else if (!path) {
pr_warn("no path to unpin map '%s' from\n",
bpf_map__name(map));
return -EINVAL;
}
err = check_path(path);
if (err)
return err;
err = unlink(path);
if (err != 0)
return -errno;
map->pinned = false;
pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path);
return 0;
}
int bpf_map__set_pin_path(struct bpf_map *map, const char *path)
{
char *new = NULL;
if (path) {
new = strdup(path);
if (!new)
return -errno;
}
free(map->pin_path);
map->pin_path = new;
return 0;
}
const char *bpf_map__get_pin_path(const struct bpf_map *map)
{
return map->pin_path;
}
bool bpf_map__is_pinned(const struct bpf_map *map)
{
return map->pinned;
}
static void sanitize_pin_path(char *s)
{
/* bpffs disallows periods in path names */
while (*s) {
if (*s == '.')
*s = '_';
s++;
}
}
int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
{
struct bpf_map *map;
int err;
if (!obj)
return -ENOENT;
if (!obj->loaded) {
pr_warn("object not yet loaded; load it first\n");
return -ENOENT;
}
bpf_object__for_each_map(map, obj) {
char *pin_path = NULL;
char buf[PATH_MAX];
if (path) {
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
bpf_map__name(map));
if (len < 0) {
err = -EINVAL;
goto err_unpin_maps;
} else if (len >= PATH_MAX) {
err = -ENAMETOOLONG;
goto err_unpin_maps;
}
sanitize_pin_path(buf);
pin_path = buf;
} else if (!map->pin_path) {
continue;
}
err = bpf_map__pin(map, pin_path);
if (err)
goto err_unpin_maps;
}
return 0;
err_unpin_maps:
while ((map = bpf_map__prev(map, obj))) {
if (!map->pin_path)
continue;
bpf_map__unpin(map, NULL);
}
return err;
}
int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
{
struct bpf_map *map;
int err;
if (!obj)
return -ENOENT;
bpf_object__for_each_map(map, obj) {
char *pin_path = NULL;
char buf[PATH_MAX];
if (path) {
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
bpf_map__name(map));
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
sanitize_pin_path(buf);
pin_path = buf;
} else if (!map->pin_path) {
continue;
}
err = bpf_map__unpin(map, pin_path);
if (err)
return err;
}
return 0;
}
int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
{
struct bpf_program *prog;
int err;
if (!obj)
return -ENOENT;
if (!obj->loaded) {
pr_warn("object not yet loaded; load it first\n");
return -ENOENT;
}
bpf_object__for_each_program(prog, obj) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
prog->pin_name);
if (len < 0) {
err = -EINVAL;
goto err_unpin_programs;
} else if (len >= PATH_MAX) {
err = -ENAMETOOLONG;
goto err_unpin_programs;
}
err = bpf_program__pin(prog, buf);
if (err)
goto err_unpin_programs;
}
return 0;
err_unpin_programs:
while ((prog = bpf_program__prev(prog, obj))) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
prog->pin_name);
if (len < 0)
continue;
else if (len >= PATH_MAX)
continue;
bpf_program__unpin(prog, buf);
}
return err;
}
int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
{
struct bpf_program *prog;
int err;
if (!obj)
return -ENOENT;
bpf_object__for_each_program(prog, obj) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
prog->pin_name);
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
err = bpf_program__unpin(prog, buf);
if (err)
return err;
}
return 0;
}
int bpf_object__pin(struct bpf_object *obj, const char *path)
{
int err;
err = bpf_object__pin_maps(obj, path);
if (err)
return err;
err = bpf_object__pin_programs(obj, path);
if (err) {
bpf_object__unpin_maps(obj, path);
return err;
}
return 0;
}
static void bpf_map__destroy(struct bpf_map *map)
{
if (map->clear_priv)
map->clear_priv(map, map->priv);
map->priv = NULL;
map->clear_priv = NULL;
if (map->inner_map) {
bpf_map__destroy(map->inner_map);
zfree(&map->inner_map);
}
zfree(&map->init_slots);
map->init_slots_sz = 0;
if (map->mmaped) {
munmap(map->mmaped, bpf_map_mmap_sz(map));
map->mmaped = NULL;
}
if (map->st_ops) {
zfree(&map->st_ops->data);
zfree(&map->st_ops->progs);
zfree(&map->st_ops->kern_func_off);
zfree(&map->st_ops);
}
zfree(&map->name);
zfree(&map->pin_path);
if (map->fd >= 0)
zclose(map->fd);
}
void bpf_object__close(struct bpf_object *obj)
{
size_t i;
if (IS_ERR_OR_NULL(obj))
return;
if (obj->clear_priv)
obj->clear_priv(obj, obj->priv);
bpf_object__elf_finish(obj);
bpf_object__unload(obj);
btf__free(obj->btf);
btf_ext__free(obj->btf_ext);
for (i = 0; i < obj->nr_maps; i++)
bpf_map__destroy(&obj->maps[i]);
zfree(&obj->kconfig);
zfree(&obj->externs);
obj->nr_extern = 0;
zfree(&obj->maps);
obj->nr_maps = 0;
if (obj->programs && obj->nr_programs) {
for (i = 0; i < obj->nr_programs; i++)
bpf_program__exit(&obj->programs[i]);
}
zfree(&obj->programs);
list_del(&obj->list);
free(obj);
}
struct bpf_object *
bpf_object__next(struct bpf_object *prev)
{
struct bpf_object *next;
if (!prev)
next = list_first_entry(&bpf_objects_list,
struct bpf_object,
list);
else
next = list_next_entry(prev, list);
/* Empty list is noticed here so don't need checking on entry. */
if (&next->list == &bpf_objects_list)
return NULL;
return next;
}
const char *bpf_object__name(const struct bpf_object *obj)
{
return obj ? obj->name : ERR_PTR(-EINVAL);
}
unsigned int bpf_object__kversion(const struct bpf_object *obj)
{
return obj ? obj->kern_version : 0;
}
struct btf *bpf_object__btf(const struct bpf_object *obj)
{
return obj ? obj->btf : NULL;
}
int bpf_object__btf_fd(const struct bpf_object *obj)
{
return obj->btf ? btf__fd(obj->btf) : -1;
}
int bpf_object__set_priv(struct bpf_object *obj, void *priv,
bpf_object_clear_priv_t clear_priv)
{
if (obj->priv && obj->clear_priv)
obj->clear_priv(obj, obj->priv);
obj->priv = priv;
obj->clear_priv = clear_priv;
return 0;
}
void *bpf_object__priv(const struct bpf_object *obj)
{
return obj ? obj->priv : ERR_PTR(-EINVAL);
}
static struct bpf_program *
__bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj,
bool forward)
{
size_t nr_programs = obj->nr_programs;
ssize_t idx;
if (!nr_programs)
return NULL;
if (!p)
/* Iter from the beginning */
return forward ? &obj->programs[0] :
&obj->programs[nr_programs - 1];
if (p->obj != obj) {
pr_warn("error: program handler doesn't match object\n");
return NULL;
}
idx = (p - obj->programs) + (forward ? 1 : -1);
if (idx >= obj->nr_programs || idx < 0)
return NULL;
return &obj->programs[idx];
}
struct bpf_program *
bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj)
{
struct bpf_program *prog = prev;
do {
prog = __bpf_program__iter(prog, obj, true);
} while (prog && prog_is_subprog(obj, prog));
return prog;
}
struct bpf_program *
bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj)
{
struct bpf_program *prog = next;
do {
prog = __bpf_program__iter(prog, obj, false);
} while (prog && prog_is_subprog(obj, prog));
return prog;
}
int bpf_program__set_priv(struct bpf_program *prog, void *priv,
bpf_program_clear_priv_t clear_priv)
{
if (prog->priv && prog->clear_priv)
prog->clear_priv(prog, prog->priv);
prog->priv = priv;
prog->clear_priv = clear_priv;
return 0;
}
void *bpf_program__priv(const struct bpf_program *prog)
{
return prog ? prog->priv : ERR_PTR(-EINVAL);
}
void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex)
{
prog->prog_ifindex = ifindex;
}
const char *bpf_program__name(const struct bpf_program *prog)
{
return prog->name;
}
const char *bpf_program__section_name(const struct bpf_program *prog)
{
return prog->sec_name;
}
const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy)
{
const char *title;
title = prog->sec_name;
if (needs_copy) {
title = strdup(title);
if (!title) {
pr_warn("failed to strdup program title\n");
return ERR_PTR(-ENOMEM);
}
}
return title;
}
bool bpf_program__autoload(const struct bpf_program *prog)
{
return prog->load;
}
int bpf_program__set_autoload(struct bpf_program *prog, bool autoload)
{
if (prog->obj->loaded)
return -EINVAL;
prog->load = autoload;
return 0;
}
int bpf_program__fd(const struct bpf_program *prog)
{
return bpf_program__nth_fd(prog, 0);
}
size_t bpf_program__size(const struct bpf_program *prog)
{
return prog->insns_cnt * BPF_INSN_SZ;
}
int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
bpf_program_prep_t prep)
{
int *instances_fds;
if (nr_instances <= 0 || !prep)
return -EINVAL;
if (prog->instances.nr > 0 || prog->instances.fds) {
pr_warn("Can't set pre-processor after loading\n");
return -EINVAL;
}
instances_fds = malloc(sizeof(int) * nr_instances);
if (!instances_fds) {
pr_warn("alloc memory failed for fds\n");
return -ENOMEM;
}
/* fill all fd with -1 */
memset(instances_fds, -1, sizeof(int) * nr_instances);
prog->instances.nr = nr_instances;
prog->instances.fds = instances_fds;
prog->preprocessor = prep;
return 0;
}
int bpf_program__nth_fd(const struct bpf_program *prog, int n)
{
int fd;
if (!prog)
return -EINVAL;
if (n >= prog->instances.nr || n < 0) {
pr_warn("Can't get the %dth fd from program %s: only %d instances\n",
n, prog->name, prog->instances.nr);
return -EINVAL;
}
fd = prog->instances.fds[n];
if (fd < 0) {
pr_warn("%dth instance of program '%s' is invalid\n",
n, prog->name);
return -ENOENT;
}
return fd;
}
enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog)
{
return prog->type;
}
void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
{
prog->type = type;
}
static bool bpf_program__is_type(const struct bpf_program *prog,
enum bpf_prog_type type)
{
return prog ? (prog->type == type) : false;
}
#define BPF_PROG_TYPE_FNS(NAME, TYPE) \
int bpf_program__set_##NAME(struct bpf_program *prog) \
{ \
if (!prog) \
return -EINVAL; \
bpf_program__set_type(prog, TYPE); \
return 0; \
} \
\
bool bpf_program__is_##NAME(const struct bpf_program *prog) \
{ \
return bpf_program__is_type(prog, TYPE); \
} \
BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
BPF_PROG_TYPE_FNS(lsm, BPF_PROG_TYPE_LSM);
BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING);
BPF_PROG_TYPE_FNS(struct_ops, BPF_PROG_TYPE_STRUCT_OPS);
BPF_PROG_TYPE_FNS(extension, BPF_PROG_TYPE_EXT);
BPF_PROG_TYPE_FNS(sk_lookup, BPF_PROG_TYPE_SK_LOOKUP);
enum bpf_attach_type
bpf_program__get_expected_attach_type(struct bpf_program *prog)
{
return prog->expected_attach_type;
}
void bpf_program__set_expected_attach_type(struct bpf_program *prog,
enum bpf_attach_type type)
{
prog->expected_attach_type = type;
}
#define BPF_PROG_SEC_IMPL(string, ptype, eatype, eatype_optional, \
attachable, attach_btf) \
{ \
.sec = string, \
.len = sizeof(string) - 1, \
.prog_type = ptype, \
.expected_attach_type = eatype, \
.is_exp_attach_type_optional = eatype_optional, \
.is_attachable = attachable, \
.is_attach_btf = attach_btf, \
}
/* Programs that can NOT be attached. */
#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0, 0)
/* Programs that can be attached. */
#define BPF_APROG_SEC(string, ptype, atype) \
BPF_PROG_SEC_IMPL(string, ptype, atype, true, 1, 0)
/* Programs that must specify expected attach type at load time. */
#define BPF_EAPROG_SEC(string, ptype, eatype) \
BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 1, 0)
/* Programs that use BTF to identify attach point */
#define BPF_PROG_BTF(string, ptype, eatype) \
BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 0, 1)
/* Programs that can be attached but attach type can't be identified by section
* name. Kept for backward compatibility.
*/
#define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
#define SEC_DEF(sec_pfx, ptype, ...) { \
.sec = sec_pfx, \
.len = sizeof(sec_pfx) - 1, \
.prog_type = BPF_PROG_TYPE_##ptype, \
__VA_ARGS__ \
}
static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
struct bpf_program *prog);
static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
struct bpf_program *prog);
static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
struct bpf_program *prog);
static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
struct bpf_program *prog);
static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
struct bpf_program *prog);
static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,
struct bpf_program *prog);
static const struct bpf_sec_def section_defs[] = {
BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER),
BPF_PROG_SEC("sk_reuseport", BPF_PROG_TYPE_SK_REUSEPORT),
SEC_DEF("kprobe/", KPROBE,
.attach_fn = attach_kprobe),
BPF_PROG_SEC("uprobe/", BPF_PROG_TYPE_KPROBE),
SEC_DEF("kretprobe/", KPROBE,
.attach_fn = attach_kprobe),
BPF_PROG_SEC("uretprobe/", BPF_PROG_TYPE_KPROBE),
BPF_PROG_SEC("classifier", BPF_PROG_TYPE_SCHED_CLS),
BPF_PROG_SEC("action", BPF_PROG_TYPE_SCHED_ACT),
SEC_DEF("tracepoint/", TRACEPOINT,
.attach_fn = attach_tp),
SEC_DEF("tp/", TRACEPOINT,
.attach_fn = attach_tp),
SEC_DEF("raw_tracepoint/", RAW_TRACEPOINT,
.attach_fn = attach_raw_tp),
SEC_DEF("raw_tp/", RAW_TRACEPOINT,
.attach_fn = attach_raw_tp),
SEC_DEF("tp_btf/", TRACING,
.expected_attach_type = BPF_TRACE_RAW_TP,
.is_attach_btf = true,
.attach_fn = attach_trace),
SEC_DEF("fentry/", TRACING,
.expected_attach_type = BPF_TRACE_FENTRY,
.is_attach_btf = true,
.attach_fn = attach_trace),
SEC_DEF("fmod_ret/", TRACING,
.expected_attach_type = BPF_MODIFY_RETURN,
.is_attach_btf = true,
.attach_fn = attach_trace),
SEC_DEF("fexit/", TRACING,
.expected_attach_type = BPF_TRACE_FEXIT,
.is_attach_btf = true,
.attach_fn = attach_trace),
SEC_DEF("fentry.s/", TRACING,
.expected_attach_type = BPF_TRACE_FENTRY,
.is_attach_btf = true,
.is_sleepable = true,
.attach_fn = attach_trace),
SEC_DEF("fmod_ret.s/", TRACING,
.expected_attach_type = BPF_MODIFY_RETURN,
.is_attach_btf = true,
.is_sleepable = true,
.attach_fn = attach_trace),
SEC_DEF("fexit.s/", TRACING,
.expected_attach_type = BPF_TRACE_FEXIT,
.is_attach_btf = true,
.is_sleepable = true,
.attach_fn = attach_trace),
SEC_DEF("freplace/", EXT,
.is_attach_btf = true,
.attach_fn = attach_trace),
SEC_DEF("lsm/", LSM,
.is_attach_btf = true,
.expected_attach_type = BPF_LSM_MAC,
.attach_fn = attach_lsm),
SEC_DEF("lsm.s/", LSM,
.is_attach_btf = true,
.is_sleepable = true,
.expected_attach_type = BPF_LSM_MAC,
.attach_fn = attach_lsm),
SEC_DEF("iter/", TRACING,
.expected_attach_type = BPF_TRACE_ITER,
.is_attach_btf = true,
.attach_fn = attach_iter),
BPF_EAPROG_SEC("xdp_devmap/", BPF_PROG_TYPE_XDP,
BPF_XDP_DEVMAP),
BPF_EAPROG_SEC("xdp_cpumap/", BPF_PROG_TYPE_XDP,
BPF_XDP_CPUMAP),
BPF_APROG_SEC("xdp", BPF_PROG_TYPE_XDP,
BPF_XDP),
BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
BPF_PROG_SEC("lwt_out", BPF_PROG_TYPE_LWT_OUT),
BPF_PROG_SEC("lwt_xmit", BPF_PROG_TYPE_LWT_XMIT),
BPF_PROG_SEC("lwt_seg6local", BPF_PROG_TYPE_LWT_SEG6LOCAL),
BPF_APROG_SEC("cgroup_skb/ingress", BPF_PROG_TYPE_CGROUP_SKB,
BPF_CGROUP_INET_INGRESS),
BPF_APROG_SEC("cgroup_skb/egress", BPF_PROG_TYPE_CGROUP_SKB,
BPF_CGROUP_INET_EGRESS),
BPF_APROG_COMPAT("cgroup/skb", BPF_PROG_TYPE_CGROUP_SKB),
BPF_EAPROG_SEC("cgroup/sock_create", BPF_PROG_TYPE_CGROUP_SOCK,
BPF_CGROUP_INET_SOCK_CREATE),
BPF_EAPROG_SEC("cgroup/sock_release", BPF_PROG_TYPE_CGROUP_SOCK,
BPF_CGROUP_INET_SOCK_RELEASE),
BPF_APROG_SEC("cgroup/sock", BPF_PROG_TYPE_CGROUP_SOCK,
BPF_CGROUP_INET_SOCK_CREATE),
BPF_EAPROG_SEC("cgroup/post_bind4", BPF_PROG_TYPE_CGROUP_SOCK,
BPF_CGROUP_INET4_POST_BIND),
BPF_EAPROG_SEC("cgroup/post_bind6", BPF_PROG_TYPE_CGROUP_SOCK,
BPF_CGROUP_INET6_POST_BIND),
BPF_APROG_SEC("cgroup/dev", BPF_PROG_TYPE_CGROUP_DEVICE,
BPF_CGROUP_DEVICE),
BPF_APROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS,
BPF_CGROUP_SOCK_OPS),
BPF_APROG_SEC("sk_skb/stream_parser", BPF_PROG_TYPE_SK_SKB,
BPF_SK_SKB_STREAM_PARSER),
BPF_APROG_SEC("sk_skb/stream_verdict", BPF_PROG_TYPE_SK_SKB,
BPF_SK_SKB_STREAM_VERDICT),
BPF_APROG_COMPAT("sk_skb", BPF_PROG_TYPE_SK_SKB),
BPF_APROG_SEC("sk_msg", BPF_PROG_TYPE_SK_MSG,
BPF_SK_MSG_VERDICT),
BPF_APROG_SEC("lirc_mode2", BPF_PROG_TYPE_LIRC_MODE2,
BPF_LIRC_MODE2),
BPF_APROG_SEC("flow_dissector", BPF_PROG_TYPE_FLOW_DISSECTOR,
BPF_FLOW_DISSECTOR),
BPF_EAPROG_SEC("cgroup/bind4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET4_BIND),
BPF_EAPROG_SEC("cgroup/bind6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET6_BIND),
BPF_EAPROG_SEC("cgroup/connect4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET4_CONNECT),
BPF_EAPROG_SEC("cgroup/connect6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET6_CONNECT),
BPF_EAPROG_SEC("cgroup/sendmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP4_SENDMSG),
BPF_EAPROG_SEC("cgroup/sendmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP6_SENDMSG),
BPF_EAPROG_SEC("cgroup/recvmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP4_RECVMSG),
BPF_EAPROG_SEC("cgroup/recvmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP6_RECVMSG),
BPF_EAPROG_SEC("cgroup/getpeername4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET4_GETPEERNAME),
BPF_EAPROG_SEC("cgroup/getpeername6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET6_GETPEERNAME),
BPF_EAPROG_SEC("cgroup/getsockname4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET4_GETSOCKNAME),
BPF_EAPROG_SEC("cgroup/getsockname6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET6_GETSOCKNAME),
BPF_EAPROG_SEC("cgroup/sysctl", BPF_PROG_TYPE_CGROUP_SYSCTL,
BPF_CGROUP_SYSCTL),
BPF_EAPROG_SEC("cgroup/getsockopt", BPF_PROG_TYPE_CGROUP_SOCKOPT,
BPF_CGROUP_GETSOCKOPT),
BPF_EAPROG_SEC("cgroup/setsockopt", BPF_PROG_TYPE_CGROUP_SOCKOPT,
BPF_CGROUP_SETSOCKOPT),
BPF_PROG_SEC("struct_ops", BPF_PROG_TYPE_STRUCT_OPS),
BPF_EAPROG_SEC("sk_lookup/", BPF_PROG_TYPE_SK_LOOKUP,
BPF_SK_LOOKUP),
};
#undef BPF_PROG_SEC_IMPL
#undef BPF_PROG_SEC
#undef BPF_APROG_SEC
#undef BPF_EAPROG_SEC
#undef BPF_APROG_COMPAT
#undef SEC_DEF
#define MAX_TYPE_NAME_SIZE 32
static const struct bpf_sec_def *find_sec_def(const char *sec_name)
{
int i, n = ARRAY_SIZE(section_defs);
for (i = 0; i < n; i++) {
if (strncmp(sec_name,
section_defs[i].sec, section_defs[i].len))
continue;
return &section_defs[i];
}
return NULL;
}
static char *libbpf_get_type_names(bool attach_type)
{
int i, len = ARRAY_SIZE(section_defs) * MAX_TYPE_NAME_SIZE;
char *buf;
buf = malloc(len);
if (!buf)
return NULL;
buf[0] = '\0';
/* Forge string buf with all available names */
for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
if (attach_type && !section_defs[i].is_attachable)
continue;
if (strlen(buf) + strlen(section_defs[i].sec) + 2 > len) {
free(buf);
return NULL;
}
strcat(buf, " ");
strcat(buf, section_defs[i].sec);
}
return buf;
}
int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
enum bpf_attach_type *expected_attach_type)
{
const struct bpf_sec_def *sec_def;
char *type_names;
if (!name)
return -EINVAL;
sec_def = find_sec_def(name);
if (sec_def) {
*prog_type = sec_def->prog_type;
*expected_attach_type = sec_def->expected_attach_type;
return 0;
}
pr_debug("failed to guess program type from ELF section '%s'\n", name);
type_names = libbpf_get_type_names(false);
if (type_names != NULL) {
pr_debug("supported section(type) names are:%s\n", type_names);
free(type_names);
}
return -ESRCH;
}
static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj,
size_t offset)
{
struct bpf_map *map;
size_t i;
for (i = 0; i < obj->nr_maps; i++) {
map = &obj->maps[i];
if (!bpf_map__is_struct_ops(map))
continue;
if (map->sec_offset <= offset &&
offset - map->sec_offset < map->def.value_size)
return map;
}
return NULL;
}
/* Collect the reloc from ELF and populate the st_ops->progs[] */
static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
GElf_Shdr *shdr, Elf_Data *data)
{
const struct btf_member *member;
struct bpf_struct_ops *st_ops;
struct bpf_program *prog;
unsigned int shdr_idx;
const struct btf *btf;
struct bpf_map *map;
Elf_Data *symbols;
unsigned int moff, insn_idx;
const char *name;
__u32 member_idx;
GElf_Sym sym;
GElf_Rel rel;
int i, nrels;
symbols = obj->efile.symbols;
btf = obj->btf;
nrels = shdr->sh_size / shdr->sh_entsize;
for (i = 0; i < nrels; i++) {
if (!gelf_getrel(data, i, &rel)) {
pr_warn("struct_ops reloc: failed to get %d reloc\n", i);
return -LIBBPF_ERRNO__FORMAT;
}
if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
pr_warn("struct_ops reloc: symbol %zx not found\n",
(size_t)GELF_R_SYM(rel.r_info));
return -LIBBPF_ERRNO__FORMAT;
}
name = elf_sym_str(obj, sym.st_name) ?: "<?>";
map = find_struct_ops_map_by_offset(obj, rel.r_offset);
if (!map) {
pr_warn("struct_ops reloc: cannot find map at rel.r_offset %zu\n",
(size_t)rel.r_offset);
return -EINVAL;
}
moff = rel.r_offset - map->sec_offset;
shdr_idx = sym.st_shndx;
st_ops = map->st_ops;
pr_debug("struct_ops reloc %s: for %lld value %lld shdr_idx %u rel.r_offset %zu map->sec_offset %zu name %d (\'%s\')\n",
map->name,
(long long)(rel.r_info >> 32),
(long long)sym.st_value,
shdr_idx, (size_t)rel.r_offset,
map->sec_offset, sym.st_name, name);
if (shdr_idx >= SHN_LORESERVE) {
pr_warn("struct_ops reloc %s: rel.r_offset %zu shdr_idx %u unsupported non-static function\n",
map->name, (size_t)rel.r_offset, shdr_idx);
return -LIBBPF_ERRNO__RELOC;
}
if (sym.st_value % BPF_INSN_SZ) {
pr_warn("struct_ops reloc %s: invalid target program offset %llu\n",
map->name, (unsigned long long)sym.st_value);
return -LIBBPF_ERRNO__FORMAT;
}
insn_idx = sym.st_value / BPF_INSN_SZ;
member = find_member_by_offset(st_ops->type, moff * 8);
if (!member) {
pr_warn("struct_ops reloc %s: cannot find member at moff %u\n",
map->name, moff);
return -EINVAL;
}
member_idx = member - btf_members(st_ops->type);
name = btf__name_by_offset(btf, member->name_off);
if (!resolve_func_ptr(btf, member->type, NULL)) {
pr_warn("struct_ops reloc %s: cannot relocate non func ptr %s\n",
map->name, name);
return -EINVAL;
}
prog = find_prog_by_sec_insn(obj, shdr_idx, insn_idx);
if (!prog) {
pr_warn("struct_ops reloc %s: cannot find prog at shdr_idx %u to relocate func ptr %s\n",
map->name, shdr_idx, name);
return -EINVAL;
}
if (prog->type == BPF_PROG_TYPE_UNSPEC) {
const struct bpf_sec_def *sec_def;
sec_def = find_sec_def(prog->sec_name);
if (sec_def &&
sec_def->prog_type != BPF_PROG_TYPE_STRUCT_OPS) {
/* for pr_warn */
prog->type = sec_def->prog_type;
goto invalid_prog;
}
prog->type = BPF_PROG_TYPE_STRUCT_OPS;
prog->attach_btf_id = st_ops->type_id;
prog->expected_attach_type = member_idx;
} else if (prog->type != BPF_PROG_TYPE_STRUCT_OPS ||
prog->attach_btf_id != st_ops->type_id ||
prog->expected_attach_type != member_idx) {
goto invalid_prog;
}
st_ops->progs[member_idx] = prog;
}
return 0;
invalid_prog:
pr_warn("struct_ops reloc %s: cannot use prog %s in sec %s with type %u attach_btf_id %u expected_attach_type %u for func ptr %s\n",
map->name, prog->name, prog->sec_name, prog->type,
prog->attach_btf_id, prog->expected_attach_type, name);
return -EINVAL;
}
#define BTF_TRACE_PREFIX "btf_trace_"
#define BTF_LSM_PREFIX "bpf_lsm_"
#define BTF_ITER_PREFIX "bpf_iter_"
#define BTF_MAX_NAME_SIZE 128
static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
const char *name, __u32 kind)
{
char btf_type_name[BTF_MAX_NAME_SIZE];
int ret;
ret = snprintf(btf_type_name, sizeof(btf_type_name),
"%s%s", prefix, name);
/* snprintf returns the number of characters written excluding the
* the terminating null. So, if >= BTF_MAX_NAME_SIZE are written, it
* indicates truncation.
*/
if (ret < 0 || ret >= sizeof(btf_type_name))
return -ENAMETOOLONG;
return btf__find_by_name_kind(btf, btf_type_name, kind);
}
static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name,
enum bpf_attach_type attach_type)
{
int err;
if (attach_type == BPF_TRACE_RAW_TP)
err = find_btf_by_prefix_kind(btf, BTF_TRACE_PREFIX, name,
BTF_KIND_TYPEDEF);
else if (attach_type == BPF_LSM_MAC)
err = find_btf_by_prefix_kind(btf, BTF_LSM_PREFIX, name,
BTF_KIND_FUNC);
else if (attach_type == BPF_TRACE_ITER)
err = find_btf_by_prefix_kind(btf, BTF_ITER_PREFIX, name,
BTF_KIND_FUNC);
else
err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
if (err <= 0)
pr_warn("%s is not found in vmlinux BTF\n", name);
return err;
}
int libbpf_find_vmlinux_btf_id(const char *name,
enum bpf_attach_type attach_type)
{
struct btf *btf;
int err;
btf = libbpf_find_kernel_btf();
if (IS_ERR(btf)) {
pr_warn("vmlinux BTF is not found\n");
return -EINVAL;
}
err = __find_vmlinux_btf_id(btf, name, attach_type);
btf__free(btf);
return err;
}
static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
{
struct bpf_prog_info_linear *info_linear;
struct bpf_prog_info *info;
struct btf *btf = NULL;
int err = -EINVAL;
info_linear = bpf_program__get_prog_info_linear(attach_prog_fd, 0);
if (IS_ERR_OR_NULL(info_linear)) {
pr_warn("failed get_prog_info_linear for FD %d\n",
attach_prog_fd);
return -EINVAL;
}
info = &info_linear->info;
if (!info->btf_id) {
pr_warn("The target program doesn't have BTF\n");
goto out;
}
if (btf__get_from_id(info->btf_id, &btf)) {
pr_warn("Failed to get BTF of the program\n");
goto out;
}
err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
btf__free(btf);
if (err <= 0) {
pr_warn("%s is not found in prog's BTF\n", name);
goto out;
}
out:
free(info_linear);
return err;
}
static int libbpf_find_attach_btf_id(struct bpf_program *prog)
{
enum bpf_attach_type attach_type = prog->expected_attach_type;
__u32 attach_prog_fd = prog->attach_prog_fd;
const char *name = prog->sec_name;
int i, err;
if (!name)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
if (!section_defs[i].is_attach_btf)
continue;
if (strncmp(name, section_defs[i].sec, section_defs[i].len))
continue;
if (attach_prog_fd)
err = libbpf_find_prog_btf_id(name + section_defs[i].len,
attach_prog_fd);
else
err = __find_vmlinux_btf_id(prog->obj->btf_vmlinux,
name + section_defs[i].len,
attach_type);
return err;
}
pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name);
return -ESRCH;
}
int libbpf_attach_type_by_name(const char *name,
enum bpf_attach_type *attach_type)
{
char *type_names;
int i;
if (!name)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
if (strncmp(name, section_defs[i].sec, section_defs[i].len))
continue;
if (!section_defs[i].is_attachable)
return -EINVAL;
*attach_type = section_defs[i].expected_attach_type;
return 0;
}
pr_debug("failed to guess attach type based on ELF section name '%s'\n", name);
type_names = libbpf_get_type_names(true);
if (type_names != NULL) {
pr_debug("attachable section(type) names are:%s\n", type_names);
free(type_names);
}
return -EINVAL;
}
int bpf_map__fd(const struct bpf_map *map)
{
return map ? map->fd : -EINVAL;
}
const struct bpf_map_def *bpf_map__def(const struct bpf_map *map)
{
return map ? &map->def : ERR_PTR(-EINVAL);
}
const char *bpf_map__name(const struct bpf_map *map)
{
return map ? map->name : NULL;
}
enum bpf_map_type bpf_map__type(const struct bpf_map *map)
{
return map->def.type;
}
int bpf_map__set_type(struct bpf_map *map, enum bpf_map_type type)
{
if (map->fd >= 0)
return -EBUSY;
map->def.type = type;
return 0;
}
__u32 bpf_map__map_flags(const struct bpf_map *map)
{
return map->def.map_flags;
}
int bpf_map__set_map_flags(struct bpf_map *map, __u32 flags)
{
if (map->fd >= 0)
return -EBUSY;
map->def.map_flags = flags;
return 0;
}
__u32 bpf_map__numa_node(const struct bpf_map *map)
{
return map->numa_node;
}
int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node)
{
if (map->fd >= 0)
return -EBUSY;
map->numa_node = numa_node;
return 0;
}
__u32 bpf_map__key_size(const struct bpf_map *map)
{
return map->def.key_size;
}
int bpf_map__set_key_size(struct bpf_map *map, __u32 size)
{
if (map->fd >= 0)
return -EBUSY;
map->def.key_size = size;
return 0;
}
__u32 bpf_map__value_size(const struct bpf_map *map)
{
return map->def.value_size;
}
int bpf_map__set_value_size(struct bpf_map *map, __u32 size)
{
if (map->fd >= 0)
return -EBUSY;
map->def.value_size = size;
return 0;
}
__u32 bpf_map__btf_key_type_id(const struct bpf_map *map)
{
return map ? map->btf_key_type_id : 0;
}
__u32 bpf_map__btf_value_type_id(const struct bpf_map *map)
{
return map ? map->btf_value_type_id : 0;
}
int bpf_map__set_priv(struct bpf_map *map, void *priv,
bpf_map_clear_priv_t clear_priv)
{
if (!map)
return -EINVAL;
if (map->priv) {
if (map->clear_priv)
map->clear_priv(map, map->priv);
}
map->priv = priv;
map->clear_priv = clear_priv;
return 0;
}
void *bpf_map__priv(const struct bpf_map *map)
{
return map ? map->priv : ERR_PTR(-EINVAL);
}
int bpf_map__set_initial_value(struct bpf_map *map,
const void *data, size_t size)
{
if (!map->mmaped || map->libbpf_type == LIBBPF_MAP_KCONFIG ||
size != map->def.value_size || map->fd >= 0)
return -EINVAL;
memcpy(map->mmaped, data, size);
return 0;
}
bool bpf_map__is_offload_neutral(const struct bpf_map *map)
{
return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
}
bool bpf_map__is_internal(const struct bpf_map *map)
{
return map->libbpf_type != LIBBPF_MAP_UNSPEC;
}
__u32 bpf_map__ifindex(const struct bpf_map *map)
{
return map->map_ifindex;
}
int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex)
{
if (map->fd >= 0)
return -EBUSY;
map->map_ifindex = ifindex;
return 0;
}
int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
{
if (!bpf_map_type__is_map_in_map(map->def.type)) {
pr_warn("error: unsupported map type\n");
return -EINVAL;
}
if (map->inner_map_fd != -1) {
pr_warn("error: inner_map_fd already specified\n");
return -EINVAL;
}
map->inner_map_fd = fd;
return 0;
}
static struct bpf_map *
__bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i)
{
ssize_t idx;
struct bpf_map *s, *e;
if (!obj || !obj->maps)
return NULL;
s = obj->maps;
e = obj->maps + obj->nr_maps;
if ((m < s) || (m >= e)) {
pr_warn("error in %s: map handler doesn't belong to object\n",
__func__);
return NULL;
}
idx = (m - obj->maps) + i;
if (idx >= obj->nr_maps || idx < 0)
return NULL;
return &obj->maps[idx];
}
struct bpf_map *
bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj)
{
if (prev == NULL)
return obj->maps;
return __bpf_map__iter(prev, obj, 1);
}
struct bpf_map *
bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj)
{
if (next == NULL) {
if (!obj->nr_maps)
return NULL;
return obj->maps + obj->nr_maps - 1;
}
return __bpf_map__iter(next, obj, -1);
}
struct bpf_map *
bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name)
{
struct bpf_map *pos;
bpf_object__for_each_map(pos, obj) {
if (pos->name && !strcmp(pos->name, name))
return pos;
}
return NULL;
}
int
bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name)
{
return bpf_map__fd(bpf_object__find_map_by_name(obj, name));
}
struct bpf_map *
bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
{
return ERR_PTR(-ENOTSUP);
}
long libbpf_get_error(const void *ptr)
{
return PTR_ERR_OR_ZERO(ptr);
}
int bpf_prog_load(const char *file, enum bpf_prog_type type,
struct bpf_object **pobj, int *prog_fd)
{
struct bpf_prog_load_attr attr;
memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
attr.file = file;
attr.prog_type = type;
attr.expected_attach_type = 0;
return bpf_prog_load_xattr(&attr, pobj, prog_fd);
}
int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
struct bpf_object **pobj, int *prog_fd)
{
struct bpf_object_open_attr open_attr = {};
struct bpf_program *prog, *first_prog = NULL;
struct bpf_object *obj;
struct bpf_map *map;
int err;
if (!attr)
return -EINVAL;
if (!attr->file)
return -EINVAL;
open_attr.file = attr->file;
open_attr.prog_type = attr->prog_type;
obj = bpf_object__open_xattr(&open_attr);
if (IS_ERR_OR_NULL(obj))
return -ENOENT;
bpf_object__for_each_program(prog, obj) {
enum bpf_attach_type attach_type = attr->expected_attach_type;
/*
* to preserve backwards compatibility, bpf_prog_load treats
* attr->prog_type, if specified, as an override to whatever
* bpf_object__open guessed
*/
if (attr->prog_type != BPF_PROG_TYPE_UNSPEC) {
bpf_program__set_type(prog, attr->prog_type);
bpf_program__set_expected_attach_type(prog,
attach_type);
}
if (bpf_program__get_type(prog) == BPF_PROG_TYPE_UNSPEC) {
/*
* we haven't guessed from section name and user
* didn't provide a fallback type, too bad...
*/
bpf_object__close(obj);
return -EINVAL;
}
prog->prog_ifindex = attr->ifindex;
prog->log_level = attr->log_level;
prog->prog_flags |= attr->prog_flags;
if (!first_prog)
first_prog = prog;
}
bpf_object__for_each_map(map, obj) {
if (!bpf_map__is_offload_neutral(map))
map->map_ifindex = attr->ifindex;
}
if (!first_prog) {
pr_warn("object file doesn't contain bpf program\n");
bpf_object__close(obj);
return -ENOENT;
}
err = bpf_object__load(obj);
if (err) {
bpf_object__close(obj);
return err;
}
*pobj = obj;
*prog_fd = bpf_program__fd(first_prog);
return 0;
}
struct bpf_link {
int (*detach)(struct bpf_link *link);
int (*destroy)(struct bpf_link *link);
char *pin_path; /* NULL, if not pinned */
int fd; /* hook FD, -1 if not applicable */
bool disconnected;
};
/* Replace link's underlying BPF program with the new one */
int bpf_link__update_program(struct bpf_link *link, struct bpf_program *prog)
{
return bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), NULL);
}
/* Release "ownership" of underlying BPF resource (typically, BPF program
* attached to some BPF hook, e.g., tracepoint, kprobe, etc). Disconnected
* link, when destructed through bpf_link__destroy() call won't attempt to
* detach/unregisted that BPF resource. This is useful in situations where,
* say, attached BPF program has to outlive userspace program that attached it
* in the system. Depending on type of BPF program, though, there might be
* additional steps (like pinning BPF program in BPF FS) necessary to ensure
* exit of userspace program doesn't trigger automatic detachment and clean up
* inside the kernel.
*/
void bpf_link__disconnect(struct bpf_link *link)
{
link->disconnected = true;
}
int bpf_link__destroy(struct bpf_link *link)
{
int err = 0;
if (IS_ERR_OR_NULL(link))
return 0;
if (!link->disconnected && link->detach)
err = link->detach(link);
if (link->destroy)
link->destroy(link);
if (link->pin_path)
free(link->pin_path);
free(link);
return err;
}
int bpf_link__fd(const struct bpf_link *link)
{
return link->fd;
}
const char *bpf_link__pin_path(const struct bpf_link *link)
{
return link->pin_path;
}
static int bpf_link__detach_fd(struct bpf_link *link)
{
return close(link->fd);
}
struct bpf_link *bpf_link__open(const char *path)
{
struct bpf_link *link;
int fd;
fd = bpf_obj_get(path);
if (fd < 0) {
fd = -errno;
pr_warn("failed to open link at %s: %d\n", path, fd);
return ERR_PTR(fd);
}
link = calloc(1, sizeof(*link));
if (!link) {
close(fd);
return ERR_PTR(-ENOMEM);
}
link->detach = &bpf_link__detach_fd;
link->fd = fd;
link->pin_path = strdup(path);
if (!link->pin_path) {
bpf_link__destroy(link);
return ERR_PTR(-ENOMEM);
}
return link;
}
int bpf_link__detach(struct bpf_link *link)
{
return bpf_link_detach(link->fd) ? -errno : 0;
}
int bpf_link__pin(struct bpf_link *link, const char *path)
{
int err;
if (link->pin_path)
return -EBUSY;
err = make_parent_dir(path);
if (err)
return err;
err = check_path(path);
if (err)
return err;
link->pin_path = strdup(path);
if (!link->pin_path)
return -ENOMEM;
if (bpf_obj_pin(link->fd, link->pin_path)) {
err = -errno;
zfree(&link->pin_path);
return err;
}
pr_debug("link fd=%d: pinned at %s\n", link->fd, link->pin_path);
return 0;
}
int bpf_link__unpin(struct bpf_link *link)
{
int err;
if (!link->pin_path)
return -EINVAL;
err = unlink(link->pin_path);
if (err != 0)
return -errno;
pr_debug("link fd=%d: unpinned from %s\n", link->fd, link->pin_path);
zfree(&link->pin_path);
return 0;
}
static int bpf_link__detach_perf_event(struct bpf_link *link)
{
int err;
err = ioctl(link->fd, PERF_EVENT_IOC_DISABLE, 0);
if (err)
err = -errno;
close(link->fd);
return err;
}
struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog,
int pfd)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int prog_fd, err;
if (pfd < 0) {
pr_warn("prog '%s': invalid perf event FD %d\n",
prog->name, pfd);
return ERR_PTR(-EINVAL);
}
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warn("prog '%s': can't attach BPF program w/o FD (did you load it?)\n",
prog->name);
return ERR_PTR(-EINVAL);
}
link = calloc(1, sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
link->detach = &bpf_link__detach_perf_event;
link->fd = pfd;
if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) {
err = -errno;
free(link);
pr_warn("prog '%s': failed to attach to pfd %d: %s\n",
prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
if (err == -EPROTO)
pr_warn("prog '%s': try add PERF_SAMPLE_CALLCHAIN to or remove exclude_callchain_[kernel|user] from pfd %d\n",
prog->name, pfd);
return ERR_PTR(err);
}
if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
err = -errno;
free(link);
pr_warn("prog '%s': failed to enable pfd %d: %s\n",
prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return ERR_PTR(err);
}
return link;
}
/*
* this function is expected to parse integer in the range of [0, 2^31-1] from
* given file using scanf format string fmt. If actual parsed value is
* negative, the result might be indistinguishable from error
*/
static int parse_uint_from_file(const char *file, const char *fmt)
{
char buf[STRERR_BUFSIZE];
int err, ret;
FILE *f;
f = fopen(file, "r");
if (!f) {
err = -errno;
pr_debug("failed to open '%s': %s\n", file,
libbpf_strerror_r(err, buf, sizeof(buf)));
return err;
}
err = fscanf(f, fmt, &ret);
if (err != 1) {
err = err == EOF ? -EIO : -errno;
pr_debug("failed to parse '%s': %s\n", file,
libbpf_strerror_r(err, buf, sizeof(buf)));
fclose(f);
return err;
}
fclose(f);
return ret;
}
static int determine_kprobe_perf_type(void)
{
const char *file = "/sys/bus/event_source/devices/kprobe/type";
return parse_uint_from_file(file, "%d\n");
}
static int determine_uprobe_perf_type(void)
{
const char *file = "/sys/bus/event_source/devices/uprobe/type";
return parse_uint_from_file(file, "%d\n");
}
static int determine_kprobe_retprobe_bit(void)
{
const char *file = "/sys/bus/event_source/devices/kprobe/format/retprobe";
return parse_uint_from_file(file, "config:%d\n");
}
static int determine_uprobe_retprobe_bit(void)
{
const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
return parse_uint_from_file(file, "config:%d\n");
}
static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
uint64_t offset, int pid)
{
struct perf_event_attr attr = {};
char errmsg[STRERR_BUFSIZE];
int type, pfd, err;
type = uprobe ? determine_uprobe_perf_type()
: determine_kprobe_perf_type();
if (type < 0) {
pr_warn("failed to determine %s perf type: %s\n",
uprobe ? "uprobe" : "kprobe",
libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
return type;
}
if (retprobe) {
int bit = uprobe ? determine_uprobe_retprobe_bit()
: determine_kprobe_retprobe_bit();
if (bit < 0) {
pr_warn("failed to determine %s retprobe bit: %s\n",
uprobe ? "uprobe" : "kprobe",
libbpf_strerror_r(bit, errmsg, sizeof(errmsg)));
return bit;
}
attr.config |= 1 << bit;
}
attr.size = sizeof(attr);
attr.type = type;
attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
attr.config2 = offset; /* kprobe_addr or probe_offset */
/* pid filter is meaningful only for uprobes */
pfd = syscall(__NR_perf_event_open, &attr,
pid < 0 ? -1 : pid /* pid */,
pid == -1 ? 0 : -1 /* cpu */,
-1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
if (pfd < 0) {
err = -errno;
pr_warn("%s perf_event_open() failed: %s\n",
uprobe ? "uprobe" : "kprobe",
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return err;
}
return pfd;
}
struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
bool retprobe,
const char *func_name)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int pfd, err;
pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name,
0 /* offset */, -1 /* pid */);
if (pfd < 0) {
pr_warn("prog '%s': failed to create %s '%s' perf event: %s\n",
prog->name, retprobe ? "kretprobe" : "kprobe", func_name,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
if (IS_ERR(link)) {
close(pfd);
err = PTR_ERR(link);
pr_warn("prog '%s': failed to attach to %s '%s': %s\n",
prog->name, retprobe ? "kretprobe" : "kprobe", func_name,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return link;
}
return link;
}
static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
struct bpf_program *prog)
{
const char *func_name;
bool retprobe;
func_name = prog->sec_name + sec->len;
retprobe = strcmp(sec->sec, "kretprobe/") == 0;
return bpf_program__attach_kprobe(prog, retprobe, func_name);
}
struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
bool retprobe, pid_t pid,
const char *binary_path,
size_t func_offset)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int pfd, err;
pfd = perf_event_open_probe(true /* uprobe */, retprobe,
binary_path, func_offset, pid);
if (pfd < 0) {
pr_warn("prog '%s': failed to create %s '%s:0x%zx' perf event: %s\n",
prog->name, retprobe ? "uretprobe" : "uprobe",
binary_path, func_offset,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
if (IS_ERR(link)) {
close(pfd);
err = PTR_ERR(link);
pr_warn("prog '%s': failed to attach to %s '%s:0x%zx': %s\n",
prog->name, retprobe ? "uretprobe" : "uprobe",
binary_path, func_offset,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return link;
}
return link;
}
static int determine_tracepoint_id(const char *tp_category,
const char *tp_name)
{
char file[PATH_MAX];
int ret;
ret = snprintf(file, sizeof(file),
"/sys/kernel/debug/tracing/events/%s/%s/id",
tp_category, tp_name);
if (ret < 0)
return -errno;
if (ret >= sizeof(file)) {
pr_debug("tracepoint %s/%s path is too long\n",
tp_category, tp_name);
return -E2BIG;
}
return parse_uint_from_file(file, "%d\n");
}
static int perf_event_open_tracepoint(const char *tp_category,
const char *tp_name)
{
struct perf_event_attr attr = {};
char errmsg[STRERR_BUFSIZE];
int tp_id, pfd, err;
tp_id = determine_tracepoint_id(tp_category, tp_name);
if (tp_id < 0) {
pr_warn("failed to determine tracepoint '%s/%s' perf event ID: %s\n",
tp_category, tp_name,
libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg)));
return tp_id;
}
attr.type = PERF_TYPE_TRACEPOINT;
attr.size = sizeof(attr);
attr.config = tp_id;
pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */,
-1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
if (pfd < 0) {
err = -errno;
pr_warn("tracepoint '%s/%s' perf_event_open() failed: %s\n",
tp_category, tp_name,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return err;
}
return pfd;
}
struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
const char *tp_category,
const char *tp_name)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int pfd, err;
pfd = perf_event_open_tracepoint(tp_category, tp_name);
if (pfd < 0) {
pr_warn("prog '%s': failed to create tracepoint '%s/%s' perf event: %s\n",
prog->name, tp_category, tp_name,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
if (IS_ERR(link)) {
close(pfd);
err = PTR_ERR(link);
pr_warn("prog '%s': failed to attach to tracepoint '%s/%s': %s\n",
prog->name, tp_category, tp_name,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return link;
}
return link;
}
static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
struct bpf_program *prog)
{
char *sec_name, *tp_cat, *tp_name;
struct bpf_link *link;
sec_name = strdup(prog->sec_name);
if (!sec_name)
return ERR_PTR(-ENOMEM);
/* extract "tp/<category>/<name>" */
tp_cat = sec_name + sec->len;
tp_name = strchr(tp_cat, '/');
if (!tp_name) {
link = ERR_PTR(-EINVAL);
goto out;
}
*tp_name = '\0';
tp_name++;
link = bpf_program__attach_tracepoint(prog, tp_cat, tp_name);
out:
free(sec_name);
return link;
}
struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
const char *tp_name)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int prog_fd, pfd;
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warn("prog '%s': can't attach before loaded\n", prog->name);
return ERR_PTR(-EINVAL);
}
link = calloc(1, sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
link->detach = &bpf_link__detach_fd;
pfd = bpf_raw_tracepoint_open(tp_name, prog_fd);
if (pfd < 0) {
pfd = -errno;
free(link);
pr_warn("prog '%s': failed to attach to raw tracepoint '%s': %s\n",
prog->name, tp_name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link->fd = pfd;
return link;
}
static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
struct bpf_program *prog)
{
const char *tp_name = prog->sec_name + sec->len;
return bpf_program__attach_raw_tracepoint(prog, tp_name);
}
/* Common logic for all BPF program types that attach to a btf_id */
static struct bpf_link *bpf_program__attach_btf_id(struct bpf_program *prog)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int prog_fd, pfd;
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warn("prog '%s': can't attach before loaded\n", prog->name);
return ERR_PTR(-EINVAL);
}
link = calloc(1, sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
link->detach = &bpf_link__detach_fd;
pfd = bpf_raw_tracepoint_open(NULL, prog_fd);
if (pfd < 0) {
pfd = -errno;
free(link);
pr_warn("prog '%s': failed to attach: %s\n",
prog->name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link->fd = pfd;
return (struct bpf_link *)link;
}
struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
{
return bpf_program__attach_btf_id(prog);
}
struct bpf_link *bpf_program__attach_lsm(struct bpf_program *prog)
{
return bpf_program__attach_btf_id(prog);
}
static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
struct bpf_program *prog)
{
return bpf_program__attach_trace(prog);
}
static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
struct bpf_program *prog)
{
return bpf_program__attach_lsm(prog);
}
static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,
struct bpf_program *prog)
{
return bpf_program__attach_iter(prog, NULL);
}
static struct bpf_link *
bpf_program__attach_fd(struct bpf_program *prog, int target_fd, int btf_id,
const char *target_name)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts,
.target_btf_id = btf_id);
enum bpf_attach_type attach_type;
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int prog_fd, link_fd;
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warn("prog '%s': can't attach before loaded\n", prog->name);
return ERR_PTR(-EINVAL);
}
link = calloc(1, sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
link->detach = &bpf_link__detach_fd;
attach_type = bpf_program__get_expected_attach_type(prog);
link_fd = bpf_link_create(prog_fd, target_fd, attach_type, &opts);
if (link_fd < 0) {
link_fd = -errno;
free(link);
pr_warn("prog '%s': failed to attach to %s: %s\n",
prog->name, target_name,
libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg)));
return ERR_PTR(link_fd);
}
link->fd = link_fd;
return link;
}
struct bpf_link *
bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd)
{
return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup");
}
struct bpf_link *
bpf_program__attach_netns(struct bpf_program *prog, int netns_fd)
{
return bpf_program__attach_fd(prog, netns_fd, 0, "netns");
}
struct bpf_link *bpf_program__attach_xdp(struct bpf_program *prog, int ifindex)
{
/* target_fd/target_ifindex use the same field in LINK_CREATE */
return bpf_program__attach_fd(prog, ifindex, 0, "xdp");
}
struct bpf_link *bpf_program__attach_freplace(struct bpf_program *prog,
int target_fd,
const char *attach_func_name)
{
int btf_id;
if (!!target_fd != !!attach_func_name) {
pr_warn("prog '%s': supply none or both of target_fd and attach_func_name\n",
prog->name);
return ERR_PTR(-EINVAL);
}
if (prog->type != BPF_PROG_TYPE_EXT) {
pr_warn("prog '%s': only BPF_PROG_TYPE_EXT can attach as freplace",
prog->name);
return ERR_PTR(-EINVAL);
}
if (target_fd) {
btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd);
if (btf_id < 0)
return ERR_PTR(btf_id);
return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace");
} else {
/* no target, so use raw_tracepoint_open for compatibility
* with old kernels
*/
return bpf_program__attach_trace(prog);
}
}
struct bpf_link *
bpf_program__attach_iter(struct bpf_program *prog,
const struct bpf_iter_attach_opts *opts)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int prog_fd, link_fd;
__u32 target_fd = 0;
if (!OPTS_VALID(opts, bpf_iter_attach_opts))
return ERR_PTR(-EINVAL);
link_create_opts.iter_info = OPTS_GET(opts, link_info, (void *)0);
link_create_opts.iter_info_len = OPTS_GET(opts, link_info_len, 0);
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warn("prog '%s': can't attach before loaded\n", prog->name);
return ERR_PTR(-EINVAL);
}
link = calloc(1, sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
link->detach = &bpf_link__detach_fd;
link_fd = bpf_link_create(prog_fd, target_fd, BPF_TRACE_ITER,
&link_create_opts);
if (link_fd < 0) {
link_fd = -errno;
free(link);
pr_warn("prog '%s': failed to attach to iterator: %s\n",
prog->name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg)));
return ERR_PTR(link_fd);
}
link->fd = link_fd;
return link;
}
struct bpf_link *bpf_program__attach(struct bpf_program *prog)
{
const struct bpf_sec_def *sec_def;
sec_def = find_sec_def(prog->sec_name);
if (!sec_def || !sec_def->attach_fn)
return ERR_PTR(-ESRCH);
return sec_def->attach_fn(sec_def, prog);
}
static int bpf_link__detach_struct_ops(struct bpf_link *link)
{
__u32 zero = 0;
if (bpf_map_delete_elem(link->fd, &zero))
return -errno;
return 0;
}
struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map)
{
struct bpf_struct_ops *st_ops;
struct bpf_link *link;
__u32 i, zero = 0;
int err;
if (!bpf_map__is_struct_ops(map) || map->fd == -1)
return ERR_PTR(-EINVAL);
link = calloc(1, sizeof(*link));
if (!link)
return ERR_PTR(-EINVAL);
st_ops = map->st_ops;
for (i = 0; i < btf_vlen(st_ops->type); i++) {
struct bpf_program *prog = st_ops->progs[i];
void *kern_data;
int prog_fd;
if (!prog)
continue;
prog_fd = bpf_program__fd(prog);
kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i];
*(unsigned long *)kern_data = prog_fd;
}
err = bpf_map_update_elem(map->fd, &zero, st_ops->kern_vdata, 0);
if (err) {
err = -errno;
free(link);
return ERR_PTR(err);
}
link->detach = bpf_link__detach_struct_ops;
link->fd = map->fd;
return link;
}
enum bpf_perf_event_ret
bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
void **copy_mem, size_t *copy_size,
bpf_perf_event_print_t fn, void *private_data)
{
struct perf_event_mmap_page *header = mmap_mem;
__u64 data_head = ring_buffer_read_head(header);
__u64 data_tail = header->data_tail;
void *base = ((__u8 *)header) + page_size;
int ret = LIBBPF_PERF_EVENT_CONT;
struct perf_event_header *ehdr;
size_t ehdr_size;
while (data_head != data_tail) {
ehdr = base + (data_tail & (mmap_size - 1));
ehdr_size = ehdr->size;
if (((void *)ehdr) + ehdr_size > base + mmap_size) {
void *copy_start = ehdr;
size_t len_first = base + mmap_size - copy_start;
size_t len_secnd = ehdr_size - len_first;
if (*copy_size < ehdr_size) {
free(*copy_mem);
*copy_mem = malloc(ehdr_size);
if (!*copy_mem) {
*copy_size = 0;
ret = LIBBPF_PERF_EVENT_ERROR;
break;
}
*copy_size = ehdr_size;
}
memcpy(*copy_mem, copy_start, len_first);
memcpy(*copy_mem + len_first, base, len_secnd);
ehdr = *copy_mem;
}
ret = fn(ehdr, private_data);
data_tail += ehdr_size;
if (ret != LIBBPF_PERF_EVENT_CONT)
break;
}
ring_buffer_write_tail(header, data_tail);
return ret;
}
struct perf_buffer;
struct perf_buffer_params {
struct perf_event_attr *attr;
/* if event_cb is specified, it takes precendence */
perf_buffer_event_fn event_cb;
/* sample_cb and lost_cb are higher-level common-case callbacks */
perf_buffer_sample_fn sample_cb;
perf_buffer_lost_fn lost_cb;
void *ctx;
int cpu_cnt;
int *cpus;
int *map_keys;
};
struct perf_cpu_buf {
struct perf_buffer *pb;
void *base; /* mmap()'ed memory */
void *buf; /* for reconstructing segmented data */
size_t buf_size;
int fd;
int cpu;
int map_key;
};
struct perf_buffer {
perf_buffer_event_fn event_cb;
perf_buffer_sample_fn sample_cb;
perf_buffer_lost_fn lost_cb;
void *ctx; /* passed into callbacks */
size_t page_size;
size_t mmap_size;
struct perf_cpu_buf **cpu_bufs;
struct epoll_event *events;
int cpu_cnt; /* number of allocated CPU buffers */
int epoll_fd; /* perf event FD */
int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */
};
static void perf_buffer__free_cpu_buf(struct perf_buffer *pb,
struct perf_cpu_buf *cpu_buf)
{
if (!cpu_buf)
return;
if (cpu_buf->base &&
munmap(cpu_buf->base, pb->mmap_size + pb->page_size))
pr_warn("failed to munmap cpu_buf #%d\n", cpu_buf->cpu);
if (cpu_buf->fd >= 0) {
ioctl(cpu_buf->fd, PERF_EVENT_IOC_DISABLE, 0);
close(cpu_buf->fd);
}
free(cpu_buf->buf);
free(cpu_buf);
}
void perf_buffer__free(struct perf_buffer *pb)
{
int i;
if (IS_ERR_OR_NULL(pb))
return;
if (pb->cpu_bufs) {
for (i = 0; i < pb->cpu_cnt; i++) {
struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
if (!cpu_buf)
continue;
bpf_map_delete_elem(pb->map_fd, &cpu_buf->map_key);
perf_buffer__free_cpu_buf(pb, cpu_buf);
}
free(pb->cpu_bufs);
}
if (pb->epoll_fd >= 0)
close(pb->epoll_fd);
free(pb->events);
free(pb);
}
static struct perf_cpu_buf *
perf_buffer__open_cpu_buf(struct perf_buffer *pb, struct perf_event_attr *attr,
int cpu, int map_key)
{
struct perf_cpu_buf *cpu_buf;
char msg[STRERR_BUFSIZE];
int err;
cpu_buf = calloc(1, sizeof(*cpu_buf));
if (!cpu_buf)
return ERR_PTR(-ENOMEM);
cpu_buf->pb = pb;
cpu_buf->cpu = cpu;
cpu_buf->map_key = map_key;
cpu_buf->fd = syscall(__NR_perf_event_open, attr, -1 /* pid */, cpu,
-1, PERF_FLAG_FD_CLOEXEC);
if (cpu_buf->fd < 0) {
err = -errno;
pr_warn("failed to open perf buffer event on cpu #%d: %s\n",
cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
cpu_buf->base = mmap(NULL, pb->mmap_size + pb->page_size,
PROT_READ | PROT_WRITE, MAP_SHARED,
cpu_buf->fd, 0);
if (cpu_buf->base == MAP_FAILED) {
cpu_buf->base = NULL;
err = -errno;
pr_warn("failed to mmap perf buffer on cpu #%d: %s\n",
cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
if (ioctl(cpu_buf->fd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
err = -errno;
pr_warn("failed to enable perf buffer event on cpu #%d: %s\n",
cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
return cpu_buf;
error:
perf_buffer__free_cpu_buf(pb, cpu_buf);
return (struct perf_cpu_buf *)ERR_PTR(err);
}
static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
struct perf_buffer_params *p);
struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
const struct perf_buffer_opts *opts)
{
struct perf_buffer_params p = {};
struct perf_event_attr attr = { 0, };
attr.config = PERF_COUNT_SW_BPF_OUTPUT;
attr.type = PERF_TYPE_SOFTWARE;
attr.sample_type = PERF_SAMPLE_RAW;
attr.sample_period = 1;
attr.wakeup_events = 1;
p.attr = &attr;
p.sample_cb = opts ? opts->sample_cb : NULL;
p.lost_cb = opts ? opts->lost_cb : NULL;
p.ctx = opts ? opts->ctx : NULL;
return __perf_buffer__new(map_fd, page_cnt, &p);
}
struct perf_buffer *
perf_buffer__new_raw(int map_fd, size_t page_cnt,
const struct perf_buffer_raw_opts *opts)
{
struct perf_buffer_params p = {};
p.attr = opts->attr;
p.event_cb = opts->event_cb;
p.ctx = opts->ctx;
p.cpu_cnt = opts->cpu_cnt;
p.cpus = opts->cpus;
p.map_keys = opts->map_keys;
return __perf_buffer__new(map_fd, page_cnt, &p);
}
static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
struct perf_buffer_params *p)
{
const char *online_cpus_file = "/sys/devices/system/cpu/online";
struct bpf_map_info map;
char msg[STRERR_BUFSIZE];
struct perf_buffer *pb;
bool *online = NULL;
__u32 map_info_len;
int err, i, j, n;
if (page_cnt & (page_cnt - 1)) {
pr_warn("page count should be power of two, but is %zu\n",
page_cnt);
return ERR_PTR(-EINVAL);
}
/* best-effort sanity checks */
memset(&map, 0, sizeof(map));
map_info_len = sizeof(map);
err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len);
if (err) {
err = -errno;
/* if BPF_OBJ_GET_INFO_BY_FD is supported, will return
* -EBADFD, -EFAULT, or -E2BIG on real error
*/
if (err != -EINVAL) {
pr_warn("failed to get map info for map FD %d: %s\n",
map_fd, libbpf_strerror_r(err, msg, sizeof(msg)));
return ERR_PTR(err);
}
pr_debug("failed to get map info for FD %d; API not supported? Ignoring...\n",
map_fd);
} else {
if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
map.name);
return ERR_PTR(-EINVAL);
}
}
pb = calloc(1, sizeof(*pb));
if (!pb)
return ERR_PTR(-ENOMEM);
pb->event_cb = p->event_cb;
pb->sample_cb = p->sample_cb;
pb->lost_cb = p->lost_cb;
pb->ctx = p->ctx;
pb->page_size = getpagesize();
pb->mmap_size = pb->page_size * page_cnt;
pb->map_fd = map_fd;
pb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
if (pb->epoll_fd < 0) {
err = -errno;
pr_warn("failed to create epoll instance: %s\n",
libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
if (p->cpu_cnt > 0) {
pb->cpu_cnt = p->cpu_cnt;
} else {
pb->cpu_cnt = libbpf_num_possible_cpus();
if (pb->cpu_cnt < 0) {
err = pb->cpu_cnt;
goto error;
}
if (map.max_entries && map.max_entries < pb->cpu_cnt)
pb->cpu_cnt = map.max_entries;
}
pb->events = calloc(pb->cpu_cnt, sizeof(*pb->events));
if (!pb->events) {
err = -ENOMEM;
pr_warn("failed to allocate events: out of memory\n");
goto error;
}
pb->cpu_bufs = calloc(pb->cpu_cnt, sizeof(*pb->cpu_bufs));
if (!pb->cpu_bufs) {
err = -ENOMEM;
pr_warn("failed to allocate buffers: out of memory\n");
goto error;
}
err = parse_cpu_mask_file(online_cpus_file, &online, &n);
if (err) {
pr_warn("failed to get online CPU mask: %d\n", err);
goto error;
}
for (i = 0, j = 0; i < pb->cpu_cnt; i++) {
struct perf_cpu_buf *cpu_buf;
int cpu, map_key;
cpu = p->cpu_cnt > 0 ? p->cpus[i] : i;
map_key = p->cpu_cnt > 0 ? p->map_keys[i] : i;
/* in case user didn't explicitly requested particular CPUs to
* be attached to, skip offline/not present CPUs
*/
if (p->cpu_cnt <= 0 && (cpu >= n || !online[cpu]))
continue;
cpu_buf = perf_buffer__open_cpu_buf(pb, p->attr, cpu, map_key);
if (IS_ERR(cpu_buf)) {
err = PTR_ERR(cpu_buf);
goto error;
}
pb->cpu_bufs[j] = cpu_buf;
err = bpf_map_update_elem(pb->map_fd, &map_key,
&cpu_buf->fd, 0);
if (err) {
err = -errno;
pr_warn("failed to set cpu #%d, key %d -> perf FD %d: %s\n",
cpu, map_key, cpu_buf->fd,
libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
pb->events[j].events = EPOLLIN;
pb->events[j].data.ptr = cpu_buf;
if (epoll_ctl(pb->epoll_fd, EPOLL_CTL_ADD, cpu_buf->fd,
&pb->events[j]) < 0) {
err = -errno;
pr_warn("failed to epoll_ctl cpu #%d perf FD %d: %s\n",
cpu, cpu_buf->fd,
libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
j++;
}
pb->cpu_cnt = j;
free(online);
return pb;
error:
free(online);
if (pb)
perf_buffer__free(pb);
return ERR_PTR(err);
}
struct perf_sample_raw {
struct perf_event_header header;
uint32_t size;
char data[];
};
struct perf_sample_lost {
struct perf_event_header header;
uint64_t id;
uint64_t lost;
uint64_t sample_id;
};
static enum bpf_perf_event_ret
perf_buffer__process_record(struct perf_event_header *e, void *ctx)
{
struct perf_cpu_buf *cpu_buf = ctx;
struct perf_buffer *pb = cpu_buf->pb;
void *data = e;
/* user wants full control over parsing perf event */
if (pb->event_cb)
return pb->event_cb(pb->ctx, cpu_buf->cpu, e);
switch (e->type) {
case PERF_RECORD_SAMPLE: {
struct perf_sample_raw *s = data;
if (pb->sample_cb)
pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size);
break;
}
case PERF_RECORD_LOST: {
struct perf_sample_lost *s = data;
if (pb->lost_cb)
pb->lost_cb(pb->ctx, cpu_buf->cpu, s->lost);
break;
}
default:
pr_warn("unknown perf sample type %d\n", e->type);
return LIBBPF_PERF_EVENT_ERROR;
}
return LIBBPF_PERF_EVENT_CONT;
}
static int perf_buffer__process_records(struct perf_buffer *pb,
struct perf_cpu_buf *cpu_buf)
{
enum bpf_perf_event_ret ret;
ret = bpf_perf_event_read_simple(cpu_buf->base, pb->mmap_size,
pb->page_size, &cpu_buf->buf,
&cpu_buf->buf_size,
perf_buffer__process_record, cpu_buf);
if (ret != LIBBPF_PERF_EVENT_CONT)
return ret;
return 0;
}
int perf_buffer__epoll_fd(const struct perf_buffer *pb)
{
return pb->epoll_fd;
}
int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms)
{
int i, cnt, err;
cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms);
for (i = 0; i < cnt; i++) {
struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr;
err = perf_buffer__process_records(pb, cpu_buf);
if (err) {
pr_warn("error while processing records: %d\n", err);
return err;
}
}
return cnt < 0 ? -errno : cnt;
}
/* Return number of PERF_EVENT_ARRAY map slots set up by this perf_buffer
* manager.
*/
size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb)
{
return pb->cpu_cnt;
}
/*
* Return perf_event FD of a ring buffer in *buf_idx* slot of
* PERF_EVENT_ARRAY BPF map. This FD can be polled for new data using
* select()/poll()/epoll() Linux syscalls.
*/
int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx)
{
struct perf_cpu_buf *cpu_buf;
if (buf_idx >= pb->cpu_cnt)
return -EINVAL;
cpu_buf = pb->cpu_bufs[buf_idx];
if (!cpu_buf)
return -ENOENT;
return cpu_buf->fd;
}
/*
* Consume data from perf ring buffer corresponding to slot *buf_idx* in
* PERF_EVENT_ARRAY BPF map without waiting/polling. If there is no data to
* consume, do nothing and return success.
* Returns:
* - 0 on success;
* - <0 on failure.
*/
int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx)
{
struct perf_cpu_buf *cpu_buf;
if (buf_idx >= pb->cpu_cnt)
return -EINVAL;
cpu_buf = pb->cpu_bufs[buf_idx];
if (!cpu_buf)
return -ENOENT;
return perf_buffer__process_records(pb, cpu_buf);
}
int perf_buffer__consume(struct perf_buffer *pb)
{
int i, err;
for (i = 0; i < pb->cpu_cnt; i++) {
struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
if (!cpu_buf)
continue;
err = perf_buffer__process_records(pb, cpu_buf);
if (err) {
pr_warn("perf_buffer: failed to process records in buffer #%d: %d\n", i, err);
return err;
}
}
return 0;
}
struct bpf_prog_info_array_desc {
int array_offset; /* e.g. offset of jited_prog_insns */
int count_offset; /* e.g. offset of jited_prog_len */
int size_offset; /* > 0: offset of rec size,
* < 0: fix size of -size_offset
*/
};
static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = {
[BPF_PROG_INFO_JITED_INSNS] = {
offsetof(struct bpf_prog_info, jited_prog_insns),
offsetof(struct bpf_prog_info, jited_prog_len),
-1,
},
[BPF_PROG_INFO_XLATED_INSNS] = {
offsetof(struct bpf_prog_info, xlated_prog_insns),
offsetof(struct bpf_prog_info, xlated_prog_len),
-1,
},
[BPF_PROG_INFO_MAP_IDS] = {
offsetof(struct bpf_prog_info, map_ids),
offsetof(struct bpf_prog_info, nr_map_ids),
-(int)sizeof(__u32),
},
[BPF_PROG_INFO_JITED_KSYMS] = {
offsetof(struct bpf_prog_info, jited_ksyms),
offsetof(struct bpf_prog_info, nr_jited_ksyms),
-(int)sizeof(__u64),
},
[BPF_PROG_INFO_JITED_FUNC_LENS] = {
offsetof(struct bpf_prog_info, jited_func_lens),
offsetof(struct bpf_prog_info, nr_jited_func_lens),
-(int)sizeof(__u32),
},
[BPF_PROG_INFO_FUNC_INFO] = {
offsetof(struct bpf_prog_info, func_info),
offsetof(struct bpf_prog_info, nr_func_info),
offsetof(struct bpf_prog_info, func_info_rec_size),
},
[BPF_PROG_INFO_LINE_INFO] = {
offsetof(struct bpf_prog_info, line_info),
offsetof(struct bpf_prog_info, nr_line_info),
offsetof(struct bpf_prog_info, line_info_rec_size),
},
[BPF_PROG_INFO_JITED_LINE_INFO] = {
offsetof(struct bpf_prog_info, jited_line_info),
offsetof(struct bpf_prog_info, nr_jited_line_info),
offsetof(struct bpf_prog_info, jited_line_info_rec_size),
},
[BPF_PROG_INFO_PROG_TAGS] = {
offsetof(struct bpf_prog_info, prog_tags),
offsetof(struct bpf_prog_info, nr_prog_tags),
-(int)sizeof(__u8) * BPF_TAG_SIZE,
},
};
static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info,
int offset)
{
__u32 *array = (__u32 *)info;
if (offset >= 0)
return array[offset / sizeof(__u32)];
return -(int)offset;
}
static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info,
int offset)
{
__u64 *array = (__u64 *)info;
if (offset >= 0)
return array[offset / sizeof(__u64)];
return -(int)offset;
}
static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset,
__u32 val)
{
__u32 *array = (__u32 *)info;
if (offset >= 0)
array[offset / sizeof(__u32)] = val;
}
static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset,
__u64 val)
{
__u64 *array = (__u64 *)info;
if (offset >= 0)
array[offset / sizeof(__u64)] = val;
}
struct bpf_prog_info_linear *
bpf_program__get_prog_info_linear(int fd, __u64 arrays)
{
struct bpf_prog_info_linear *info_linear;
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
__u32 data_len = 0;
int i, err;
void *ptr;
if (arrays >> BPF_PROG_INFO_LAST_ARRAY)
return ERR_PTR(-EINVAL);
/* step 1: get array dimensions */
err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
if (err) {
pr_debug("can't get prog info: %s", strerror(errno));
return ERR_PTR(-EFAULT);
}
/* step 2: calculate total size of all arrays */
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
bool include_array = (arrays & (1UL << i)) > 0;
struct bpf_prog_info_array_desc *desc;
__u32 count, size;
desc = bpf_prog_info_array_desc + i;
/* kernel is too old to support this field */
if (info_len < desc->array_offset + sizeof(__u32) ||
info_len < desc->count_offset + sizeof(__u32) ||
(desc->size_offset > 0 && info_len < desc->size_offset))
include_array = false;
if (!include_array) {
arrays &= ~(1UL << i); /* clear the bit */
continue;
}
count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
size = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
data_len += count * size;
}
/* step 3: allocate continuous memory */
data_len = roundup(data_len, sizeof(__u64));
info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len);
if (!info_linear)
return ERR_PTR(-ENOMEM);
/* step 4: fill data to info_linear->info */
info_linear->arrays = arrays;
memset(&info_linear->info, 0, sizeof(info));
ptr = info_linear->data;
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u32 count, size;
if ((arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
size = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
bpf_prog_info_set_offset_u32(&info_linear->info,
desc->count_offset, count);
bpf_prog_info_set_offset_u32(&info_linear->info,
desc->size_offset, size);
bpf_prog_info_set_offset_u64(&info_linear->info,
desc->array_offset,
ptr_to_u64(ptr));
ptr += count * size;
}
/* step 5: call syscall again to get required arrays */
err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);
if (err) {
pr_debug("can't get prog info: %s", strerror(errno));
free(info_linear);
return ERR_PTR(-EFAULT);
}
/* step 6: verify the data */
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u32 v1, v2;
if ((arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
desc->count_offset);
if (v1 != v2)
pr_warn("%s: mismatch in element count\n", __func__);
v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
desc->size_offset);
if (v1 != v2)
pr_warn("%s: mismatch in rec size\n", __func__);
}
/* step 7: update info_len and data_len */
info_linear->info_len = sizeof(struct bpf_prog_info);
info_linear->data_len = data_len;
return info_linear;
}
void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear)
{
int i;
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u64 addr, offs;
if ((info_linear->arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
addr = bpf_prog_info_read_offset_u64(&info_linear->info,
desc->array_offset);
offs = addr - ptr_to_u64(info_linear->data);
bpf_prog_info_set_offset_u64(&info_linear->info,
desc->array_offset, offs);
}
}
void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear)
{
int i;
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u64 addr, offs;
if ((info_linear->arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
offs = bpf_prog_info_read_offset_u64(&info_linear->info,
desc->array_offset);
addr = offs + ptr_to_u64(info_linear->data);
bpf_prog_info_set_offset_u64(&info_linear->info,
desc->array_offset, addr);
}
}
int bpf_program__set_attach_target(struct bpf_program *prog,
int attach_prog_fd,
const char *attach_func_name)
{
int btf_id;
if (!prog || attach_prog_fd < 0 || !attach_func_name)
return -EINVAL;
if (attach_prog_fd)
btf_id = libbpf_find_prog_btf_id(attach_func_name,
attach_prog_fd);
else
btf_id = libbpf_find_vmlinux_btf_id(attach_func_name,
prog->expected_attach_type);
if (btf_id < 0)
return btf_id;
prog->attach_btf_id = btf_id;
prog->attach_prog_fd = attach_prog_fd;
return 0;
}
int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz)
{
int err = 0, n, len, start, end = -1;
bool *tmp;
*mask = NULL;
*mask_sz = 0;
/* Each sub string separated by ',' has format \d+-\d+ or \d+ */
while (*s) {
if (*s == ',' || *s == '\n') {
s++;
continue;
}
n = sscanf(s, "%d%n-%d%n", &start, &len, &end, &len);
if (n <= 0 || n > 2) {
pr_warn("Failed to get CPU range %s: %d\n", s, n);
err = -EINVAL;
goto cleanup;
} else if (n == 1) {
end = start;
}
if (start < 0 || start > end) {
pr_warn("Invalid CPU range [%d,%d] in %s\n",
start, end, s);
err = -EINVAL;
goto cleanup;
}
tmp = realloc(*mask, end + 1);
if (!tmp) {
err = -ENOMEM;
goto cleanup;
}
*mask = tmp;
memset(tmp + *mask_sz, 0, start - *mask_sz);
memset(tmp + start, 1, end - start + 1);
*mask_sz = end + 1;
s += len;
}
if (!*mask_sz) {
pr_warn("Empty CPU range\n");
return -EINVAL;
}
return 0;
cleanup:
free(*mask);
*mask = NULL;
return err;
}
int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz)
{
int fd, err = 0, len;
char buf[128];
fd = open(fcpu, O_RDONLY);
if (fd < 0) {
err = -errno;
pr_warn("Failed to open cpu mask file %s: %d\n", fcpu, err);
return err;
}
len = read(fd, buf, sizeof(buf));
close(fd);
if (len <= 0) {
err = len ? -errno : -EINVAL;
pr_warn("Failed to read cpu mask from %s: %d\n", fcpu, err);
return err;
}
if (len >= sizeof(buf)) {
pr_warn("CPU mask is too big in file %s\n", fcpu);
return -E2BIG;
}
buf[len] = '\0';
return parse_cpu_mask_str(buf, mask, mask_sz);
}
int libbpf_num_possible_cpus(void)
{
static const char *fcpu = "/sys/devices/system/cpu/possible";
static int cpus;
int err, n, i, tmp_cpus;
bool *mask;
tmp_cpus = READ_ONCE(cpus);
if (tmp_cpus > 0)
return tmp_cpus;
err = parse_cpu_mask_file(fcpu, &mask, &n);
if (err)
return err;
tmp_cpus = 0;
for (i = 0; i < n; i++) {
if (mask[i])
tmp_cpus++;
}
free(mask);
WRITE_ONCE(cpus, tmp_cpus);
return tmp_cpus;
}
int bpf_object__open_skeleton(struct bpf_object_skeleton *s,
const struct bpf_object_open_opts *opts)
{
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, skel_opts,
.object_name = s->name,
);
struct bpf_object *obj;
int i;
/* Attempt to preserve opts->object_name, unless overriden by user
* explicitly. Overwriting object name for skeletons is discouraged,
* as it breaks global data maps, because they contain object name
* prefix as their own map name prefix. When skeleton is generated,
* bpftool is making an assumption that this name will stay the same.
*/
if (opts) {
memcpy(&skel_opts, opts, sizeof(*opts));
if (!opts->object_name)
skel_opts.object_name = s->name;
}
obj = bpf_object__open_mem(s->data, s->data_sz, &skel_opts);
if (IS_ERR(obj)) {
pr_warn("failed to initialize skeleton BPF object '%s': %ld\n",
s->name, PTR_ERR(obj));
return PTR_ERR(obj);
}
*s->obj = obj;
for (i = 0; i < s->map_cnt; i++) {
struct bpf_map **map = s->maps[i].map;
const char *name = s->maps[i].name;
void **mmaped = s->maps[i].mmaped;
*map = bpf_object__find_map_by_name(obj, name);
if (!*map) {
pr_warn("failed to find skeleton map '%s'\n", name);
return -ESRCH;
}
/* externs shouldn't be pre-setup from user code */
if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_KCONFIG)
*mmaped = (*map)->mmaped;
}
for (i = 0; i < s->prog_cnt; i++) {
struct bpf_program **prog = s->progs[i].prog;
const char *name = s->progs[i].name;
*prog = bpf_object__find_program_by_name(obj, name);
if (!*prog) {
pr_warn("failed to find skeleton program '%s'\n", name);
return -ESRCH;
}
}
return 0;
}
int bpf_object__load_skeleton(struct bpf_object_skeleton *s)
{
int i, err;
err = bpf_object__load(*s->obj);
if (err) {
pr_warn("failed to load BPF skeleton '%s': %d\n", s->name, err);
return err;
}
for (i = 0; i < s->map_cnt; i++) {
struct bpf_map *map = *s->maps[i].map;
size_t mmap_sz = bpf_map_mmap_sz(map);
int prot, map_fd = bpf_map__fd(map);
void **mmaped = s->maps[i].mmaped;
if (!mmaped)
continue;
if (!(map->def.map_flags & BPF_F_MMAPABLE)) {
*mmaped = NULL;
continue;
}
if (map->def.map_flags & BPF_F_RDONLY_PROG)
prot = PROT_READ;
else
prot = PROT_READ | PROT_WRITE;
/* Remap anonymous mmap()-ed "map initialization image" as
* a BPF map-backed mmap()-ed memory, but preserving the same
* memory address. This will cause kernel to change process'
* page table to point to a different piece of kernel memory,
* but from userspace point of view memory address (and its
* contents, being identical at this point) will stay the
* same. This mapping will be released by bpf_object__close()
* as per normal clean up procedure, so we don't need to worry
* about it from skeleton's clean up perspective.
*/
*mmaped = mmap(map->mmaped, mmap_sz, prot,
MAP_SHARED | MAP_FIXED, map_fd, 0);
if (*mmaped == MAP_FAILED) {
err = -errno;
*mmaped = NULL;
pr_warn("failed to re-mmap() map '%s': %d\n",
bpf_map__name(map), err);
return err;
}
}
return 0;
}
int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
{
int i;
for (i = 0; i < s->prog_cnt; i++) {
struct bpf_program *prog = *s->progs[i].prog;
struct bpf_link **link = s->progs[i].link;
const struct bpf_sec_def *sec_def;
if (!prog->load)
continue;
sec_def = find_sec_def(prog->sec_name);
if (!sec_def || !sec_def->attach_fn)
continue;
*link = sec_def->attach_fn(sec_def, prog);
if (IS_ERR(*link)) {
pr_warn("failed to auto-attach program '%s': %ld\n",
bpf_program__name(prog), PTR_ERR(*link));
return PTR_ERR(*link);
}
}
return 0;
}
void bpf_object__detach_skeleton(struct bpf_object_skeleton *s)
{
int i;
for (i = 0; i < s->prog_cnt; i++) {
struct bpf_link **link = s->progs[i].link;
bpf_link__destroy(*link);
*link = NULL;
}
}
void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s)
{
if (s->progs)
bpf_object__detach_skeleton(s);
if (s->obj)
bpf_object__close(*s->obj);
free(s->maps);
free(s->progs);
free(s);
}