init/initramfs.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 #include <linux/init.h>
 #include <linux/async.h>
 #include <linux/fs.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/fcntl.h>
 #include <linux/delay.h>
 #include <linux/string.h>
 #include <linux/dirent.h>
 #include <linux/syscalls.h>
 #include <linux/utime.h>
 #include <linux/file.h>
 #include <linux/memblock.h>
 #include <linux/mm.h>
 #include <linux/namei.h>
 #include <linux/init_syscalls.h>
 #include <linux/umh.h>

 static ssize_t __init xwrite(struct file *file, const char *p, size_t count,
 		loff_t *pos)
 {
 	ssize_t out = 0;

 	/* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
 	while (count) {
 		ssize_t rv = kernel_write(file, p, count, pos);

 		if (rv < 0) {
 			if (rv == -EINTR || rv == -EAGAIN)
 				continue;
 			return out ? out : rv;
 		} else if (rv == 0)
 			break;

 		p += rv;
 		out += rv;
 		count -= rv;
 	}

 	return out;
 }

 static __initdata char *message;
 static void __init error(char *x)
 {
 	if (!message)
 		message = x;
 }

 static void panic_show_mem(const char *fmt, ...)
 {
 	va_list args;

 	show_mem(0, NULL);
 	va_start(args, fmt);
 	panic(fmt, args);
 	va_end(args);
 }

 /* link hash */

 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)

 static __initdata struct hash {
 	int ino, minor, major;
 	umode_t mode;
 	struct hash *next;
 	char name[N_ALIGN(PATH_MAX)];
 } *head[32];

 static inline int hash(int major, int minor, int ino)
 {
 	unsigned long tmp = ino + minor + (major << 3);
 	tmp += tmp >> 5;
 	return tmp & 31;
 }

 static char __init *find_link(int major, int minor, int ino,
 			      umode_t mode, char *name)
 {
 	struct hash **p, *q;
 	for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
 		if ((*p)->ino != ino)
 			continue;
 		if ((*p)->minor != minor)
 			continue;
 		if ((*p)->major != major)
 			continue;
 		if (((*p)->mode ^ mode) & S_IFMT)
 			continue;
 		return (*p)->name;
 	}
 	q = kmalloc(sizeof(struct hash), GFP_KERNEL);
 	if (!q)
 		panic_show_mem("can't allocate link hash entry");
 	q->major = major;
 	q->minor = minor;
 	q->ino = ino;
 	q->mode = mode;
 	strcpy(q->name, name);
 	q->next = NULL;
 	*p = q;
 	return NULL;
 }

 static void __init free_hash(void)
 {
 	struct hash **p, *q;
 	for (p = head; p < head + 32; p++) {
 		while (*p) {
 			q = *p;
 			*p = q->next;
 			kfree(q);
 		}
 	}
 }

 static long __init do_utime(char *filename, time64_t mtime)
 {
 	struct timespec64 t[2];

 	t[0].tv_sec = mtime;
 	t[0].tv_nsec = 0;
 	t[1].tv_sec = mtime;
 	t[1].tv_nsec = 0;
 	return init_utimes(filename, t);
 }

 static __initdata LIST_HEAD(dir_list);
 struct dir_entry {
 	struct list_head list;
 	char *name;
 	time64_t mtime;
 };

 static void __init dir_add(const char *name, time64_t mtime)
 {
 	struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
 	if (!de)
 		panic_show_mem("can't allocate dir_entry buffer");
 	INIT_LIST_HEAD(&de->list);
 	de->name = kstrdup(name, GFP_KERNEL);
 	de->mtime = mtime;
 	list_add(&de->list, &dir_list);
 }

 static void __init dir_utime(void)
 {
 	struct dir_entry *de, *tmp;
 	list_for_each_entry_safe(de, tmp, &dir_list, list) {
 		list_del(&de->list);
 		do_utime(de->name, de->mtime);
 		kfree(de->name);
 		kfree(de);
 	}
 }

 static __initdata time64_t mtime;

 /* cpio header parsing */

 static __initdata unsigned long ino, major, minor, nlink;
 static __initdata umode_t mode;
 static __initdata unsigned long body_len, name_len;
 static __initdata uid_t uid;
 static __initdata gid_t gid;
 static __initdata unsigned rdev;

 static void __init parse_header(char *s)
 {
 	unsigned long parsed[12];
 	char buf[9];
 	int i;

 	buf[8] = '\0';
 	for (i = 0, s += 6; i < 12; i++, s += 8) {
 		memcpy(buf, s, 8);
 		parsed[i] = simple_strtoul(buf, NULL, 16);
 	}
 	ino = parsed[0];
 	mode = parsed[1];
 	uid = parsed[2];
 	gid = parsed[3];
 	nlink = parsed[4];
 	mtime = parsed[5]; /* breaks in y2106 */
 	body_len = parsed[6];
 	major = parsed[7];
 	minor = parsed[8];
 	rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 	name_len = parsed[11];
 }

 /* FSM */

 static __initdata enum state {
 	Start,
 	Collect,
 	GotHeader,
 	SkipIt,
 	GotName,
 	CopyFile,
 	GotSymlink,
 	Reset
 } state, next_state;

 static __initdata char *victim;
 static unsigned long byte_count __initdata;
 static __initdata loff_t this_header, next_header;

 static inline void __init eat(unsigned n)
 {
 	victim += n;
 	this_header += n;
 	byte_count -= n;
 }

 static __initdata char *collected;
 static long remains __initdata;
 static __initdata char *collect;

 static void __init read_into(char *buf, unsigned size, enum state next)
 {
 	if (byte_count >= size) {
 		collected = victim;
 		eat(size);
 		state = next;
 	} else {
 		collect = collected = buf;
 		remains = size;
 		next_state = next;
 		state = Collect;
 	}
 }

 static __initdata char *header_buf, *symlink_buf, *name_buf;

 static int __init do_start(void)
 {
 	read_into(header_buf, 110, GotHeader);
 	return 0;
 }

 static int __init do_collect(void)
 {
 	unsigned long n = remains;
 	if (byte_count < n)
 		n = byte_count;
 	memcpy(collect, victim, n);
 	eat(n);
 	collect += n;
 	if ((remains -= n) != 0)
 		return 1;
 	state = next_state;
 	return 0;
 }

 static int __init do_header(void)
 {
 	if (memcmp(collected, "070707", 6)==0) {
 		error("incorrect cpio method used: use -H newc option");
 		return 1;
 	}
 	if (memcmp(collected, "070701", 6)) {
 		error("no cpio magic");
 		return 1;
 	}
 	parse_header(collected);
 	next_header = this_header + N_ALIGN(name_len) + body_len;
 	next_header = (next_header + 3) & ~3;
 	state = SkipIt;
 	if (name_len <= 0 || name_len > PATH_MAX)
 		return 0;
 	if (S_ISLNK(mode)) {
 		if (body_len > PATH_MAX)
 			return 0;
 		collect = collected = symlink_buf;
 		remains = N_ALIGN(name_len) + body_len;
 		next_state = GotSymlink;
 		state = Collect;
 		return 0;
 	}
 	if (S_ISREG(mode) || !body_len)
 		read_into(name_buf, N_ALIGN(name_len), GotName);
 	return 0;
 }

 static int __init do_skip(void)
 {
 	if (this_header + byte_count < next_header) {
 		eat(byte_count);
 		return 1;
 	} else {
 		eat(next_header - this_header);
 		state = next_state;
 		return 0;
 	}
 }

 static int __init do_reset(void)
 {
 	while (byte_count && *victim == '\0')
 		eat(1);
 	if (byte_count && (this_header & 3))
 		error("broken padding");
 	return 1;
 }

 static void __init clean_path(char *path, umode_t fmode)
 {
 	struct kstat st;

 	if (!init_stat(path, &st, AT_SYMLINK_NOFOLLOW) &&
 	    (st.mode ^ fmode) & S_IFMT) {
 		if (S_ISDIR(st.mode))
 			init_rmdir(path);
 		else
 			init_unlink(path);
 	}
 }

 static int __init maybe_link(void)
 {
 	if (nlink >= 2) {
 		char *old = find_link(major, minor, ino, mode, collected);
 		if (old) {
 			clean_path(collected, 0);
 			return (init_link(old, collected) < 0) ? -1 : 1;
 		}
 	}
 	return 0;
 }

 static __initdata struct file *wfile;
 static __initdata loff_t wfile_pos;

 static int __init do_name(void)
 {
 	state = SkipIt;
 	next_state = Reset;

 	/* name_len > 0 && name_len <= PATH_MAX checked in do_header */
 	if (collected[name_len - 1] != '\0') {
 		pr_err("initramfs name without nulterm: %.*s\n",
 		       (int)name_len, collected);
 		error("malformed archive");
 		return 1;
 	}

 	if (strcmp(collected, "TRAILER!!!") == 0) {
 		free_hash();
 		return 0;
 	}
 	clean_path(collected, mode);
 	if (S_ISREG(mode)) {
 		int ml = maybe_link();
 		if (ml >= 0) {
 			int openflags = O_WRONLY|O_CREAT;
 			if (ml != 1)
 				openflags |= O_TRUNC;
 			wfile = filp_open(collected, openflags, mode);
 			if (IS_ERR(wfile))
 				return 0;
 			wfile_pos = 0;

 			vfs_fchown(wfile, uid, gid);
 			vfs_fchmod(wfile, mode);
 			if (body_len)
 				vfs_truncate(&wfile->f_path, body_len);
 			state = CopyFile;
 		}
 	} else if (S_ISDIR(mode)) {
 		init_mkdir(collected, mode);
 		init_chown(collected, uid, gid, 0);
 		init_chmod(collected, mode);
 		dir_add(collected, mtime);
 	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
 		if (maybe_link() == 0) {
 			init_mknod(collected, mode, rdev);
 			init_chown(collected, uid, gid, 0);
 			init_chmod(collected, mode);
 			do_utime(collected, mtime);
 		}
 	}
 	return 0;
 }

 static int __init do_copy(void)
 {
 	if (byte_count >= body_len) {
 		struct timespec64 t[2] = { };
 		if (xwrite(wfile, victim, body_len, &wfile_pos) != body_len)
 			error("write error");

 		t[0].tv_sec = mtime;
 		t[1].tv_sec = mtime;
 		vfs_utimes(&wfile->f_path, t);

 		fput(wfile);
 		eat(body_len);
 		state = SkipIt;
 		return 0;
 	} else {
 		if (xwrite(wfile, victim, byte_count, &wfile_pos) != byte_count)
 			error("write error");
 		body_len -= byte_count;
 		eat(byte_count);
 		return 1;
 	}
 }

 static int __init do_symlink(void)
 {
 	if (collected[name_len - 1] != '\0') {
 		pr_err("initramfs symlink without nulterm: %.*s\n",
 		       (int)name_len, collected);
 		error("malformed archive");
 		return 1;
 	}
 	collected[N_ALIGN(name_len) + body_len] = '\0';
 	clean_path(collected, 0);
 	init_symlink(collected + N_ALIGN(name_len), collected);
 	init_chown(collected, uid, gid, AT_SYMLINK_NOFOLLOW);
 	do_utime(collected, mtime);
 	state = SkipIt;
 	next_state = Reset;
 	return 0;
 }

 static __initdata int (*actions[])(void) = {
 	[Start]		= do_start,
 	[Collect]	= do_collect,
 	[GotHeader]	= do_header,
 	[SkipIt]	= do_skip,
 	[GotName]	= do_name,
 	[CopyFile]	= do_copy,
 	[GotSymlink]	= do_symlink,
 	[Reset]		= do_reset,
 };

 static long __init write_buffer(char *buf, unsigned long len)
 {
 	byte_count = len;
 	victim = buf;

 	while (!actions[state]())
 		;
 	return len - byte_count;
 }

 static long __init flush_buffer(void *bufv, unsigned long len)
 {
 	char *buf = (char *) bufv;
 	long written;
 	long origLen = len;
 	if (message)
 		return -1;
 	while ((written = write_buffer(buf, len)) < len && !message) {
 		char c = buf[written];
 		if (c == '0') {
 			buf += written;
 			len -= written;
 			state = Start;
 		} else if (c == 0) {
 			buf += written;
 			len -= written;
 			state = Reset;
 		} else
 			error("junk within compressed archive");
 	}
 	return origLen;
 }

 static unsigned long my_inptr; /* index of next byte to be processed in inbuf */

 #include <linux/decompress/generic.h>

 static char * __init unpack_to_rootfs(char *buf, unsigned long len)
 {
 	long written;
 	decompress_fn decompress;
 	const char *compress_name;
 	static __initdata char msg_buf[64];

 	header_buf = kmalloc(110, GFP_KERNEL);
 	symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 	name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);

 	if (!header_buf || !symlink_buf || !name_buf)
 		panic_show_mem("can't allocate buffers");

 	state = Start;
 	this_header = 0;
 	message = NULL;
 	while (!message && len) {
 		loff_t saved_offset = this_header;
 		if (*buf == '0' && !(this_header & 3)) {
 			state = Start;
 			written = write_buffer(buf, len);
 			buf += written;
 			len -= written;
 			continue;
 		}
 		if (!*buf) {
 			buf++;
 			len--;
 			this_header++;
 			continue;
 		}
 		this_header = 0;
 		decompress = decompress_method(buf, len, &compress_name);
 		pr_debug("Detected %s compressed data\n", compress_name);
 		if (decompress) {
 			int res = decompress(buf, len, NULL, flush_buffer, NULL,
 				   &my_inptr, error);
 			if (res)
 				error("decompressor failed");
 		} else if (compress_name) {
 			if (!message) {
 				snprintf(msg_buf, sizeof msg_buf,
 					 "compression method %s not configured",
 					 compress_name);
 				message = msg_buf;
 			}
 		} else
 			error("invalid magic at start of compressed archive");
 		if (state != Reset)
 			error("junk at the end of compressed archive");
 		this_header = saved_offset + my_inptr;
 		buf += my_inptr;
 		len -= my_inptr;
 	}
 	dir_utime();
 	kfree(name_buf);
 	kfree(symlink_buf);
 	kfree(header_buf);
 	return message;
 }

 static int __initdata do_retain_initrd;

 static int __init retain_initrd_param(char *str)
 {
 	if (*str)
 		return 0;
 	do_retain_initrd = 1;
 	return 1;
 }
 __setup("retain_initrd", retain_initrd_param);

 #ifdef CONFIG_ARCH_HAS_KEEPINITRD
 static int __init keepinitrd_setup(char *__unused)
 {
 	do_retain_initrd = 1;
 	return 1;
 }
 __setup("keepinitrd", keepinitrd_setup);
 #endif

 static bool __initdata initramfs_async = true;
 static int __init initramfs_async_setup(char *str)
 {
 	strtobool(str, &initramfs_async);
 	return 1;
 }
 __setup("initramfs_async=", initramfs_async_setup);

 extern char __initramfs_start[];
 extern unsigned long __initramfs_size;
 #include <linux/initrd.h>
 #include <linux/kexec.h>

 void __init reserve_initrd_mem(void)
 {
 	phys_addr_t start;
 	unsigned long size;

 	/* Ignore the virtul address computed during device tree parsing */
 	initrd_start = initrd_end = 0;

 	if (!phys_initrd_size)
 		return;
 	/*
 	 * Round the memory region to page boundaries as per free_initrd_mem()
 	 * This allows us to detect whether the pages overlapping the initrd
 	 * are in use, but more importantly, reserves the entire set of pages
 	 * as we don't want these pages allocated for other purposes.
 	 */
 	start = round_down(phys_initrd_start, PAGE_SIZE);
 	size = phys_initrd_size + (phys_initrd_start - start);
 	size = round_up(size, PAGE_SIZE);

 	if (!memblock_is_region_memory(start, size)) {
 		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
 		       (u64)start, size);
 		goto disable;
 	}

 	if (memblock_is_region_reserved(start, size)) {
 		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
 		       (u64)start, size);
 		goto disable;
 	}

 	memblock_reserve(start, size);
 	/* Now convert initrd to virtual addresses */
 	initrd_start = (unsigned long)__va(phys_initrd_start);
 	initrd_end = initrd_start + phys_initrd_size;
 	initrd_below_start_ok = 1;

 	return;
 disable:
 	pr_cont(" - disabling initrd\n");
 	initrd_start = 0;
 	initrd_end = 0;
 }

 void __weak __init free_initrd_mem(unsigned long start, unsigned long end)
 {
 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK
 	unsigned long aligned_start = ALIGN_DOWN(start, PAGE_SIZE);
 	unsigned long aligned_end = ALIGN(end, PAGE_SIZE);

 	memblock_free(__pa(aligned_start), aligned_end - aligned_start);
 #endif

 	free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
 			"initrd");
 }

 #ifdef CONFIG_KEXEC_CORE
 static bool __init kexec_free_initrd(void)
 {
 	unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 	unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);

 	/*
 	 * If the initrd region is overlapped with crashkernel reserved region,
 	 * free only memory that is not part of crashkernel region.
 	 */
 	if (initrd_start >= crashk_end || initrd_end <= crashk_start)
 		return false;

 	/*
 	 * Initialize initrd memory region since the kexec boot does not do.
 	 */
 	memset((void *)initrd_start, 0, initrd_end - initrd_start);
 	if (initrd_start < crashk_start)
 		free_initrd_mem(initrd_start, crashk_start);
 	if (initrd_end > crashk_end)
 		free_initrd_mem(crashk_end, initrd_end);
 	return true;
 }
 #else
 static inline bool kexec_free_initrd(void)
 {
 	return false;
 }
 #endif /* CONFIG_KEXEC_CORE */

 #ifdef CONFIG_BLK_DEV_RAM
 static void __init populate_initrd_image(char *err)
 {
 	ssize_t written;
 	struct file *file;
 	loff_t pos = 0;

 	unpack_to_rootfs(__initramfs_start, __initramfs_size);

 	printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
 			err);
 	file = filp_open("/initrd.image", O_WRONLY|O_CREAT|O_LARGEFILE, 0700);
 	if (IS_ERR(file))
 		return;

 	written = xwrite(file, (char *)initrd_start, initrd_end - initrd_start,
 			&pos);
 	if (written != initrd_end - initrd_start)
 		pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
 		       written, initrd_end - initrd_start);
 	fput(file);
 }
 #endif /* CONFIG_BLK_DEV_RAM */

 static void __init do_populate_rootfs(void *unused, async_cookie_t cookie)
 {
 	/* Load the built in initramfs */
 	char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
 	if (err)
 		panic_show_mem("%s", err); /* Failed to decompress INTERNAL initramfs */

 	if (!initrd_start || IS_ENABLED(CONFIG_INITRAMFS_FORCE))
 		goto done;

 	if (IS_ENABLED(CONFIG_BLK_DEV_RAM))
 		printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
 	else
 		printk(KERN_INFO "Unpacking initramfs...\n");

 	err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start);
 	if (err) {
 #ifdef CONFIG_BLK_DEV_RAM
 		populate_initrd_image(err);
 #else
 		printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
 #endif
 	}

 done:
 	/*
 	 * If the initrd region is overlapped with crashkernel reserved region,
 	 * free only memory that is not part of crashkernel region.
 	 */
 	if (!do_retain_initrd && initrd_start && !kexec_free_initrd())
 		free_initrd_mem(initrd_start, initrd_end);
 	initrd_start = 0;
 	initrd_end = 0;

 	flush_delayed_fput();
 }

 static ASYNC_DOMAIN_EXCLUSIVE(initramfs_domain);
 static async_cookie_t initramfs_cookie;

 void wait_for_initramfs(void)
 {
 	if (!initramfs_cookie) {
 		/*
 		 * Something before rootfs_initcall wants to access
 		 * the filesystem/initramfs. Probably a bug. Make a
 		 * note, avoid deadlocking the machine, and let the
 		 * caller's access fail as it used to.
 		 */
 		pr_warn_once("wait_for_initramfs() called before rootfs_initcalls\n");
 		return;
 	}
 	async_synchronize_cookie_domain(initramfs_cookie + 1, &initramfs_domain);
 }
 EXPORT_SYMBOL_GPL(wait_for_initramfs);

 static int __init populate_rootfs(void)
 {
 	initramfs_cookie = async_schedule_domain(do_populate_rootfs, NULL,
 						 &initramfs_domain);
 	usermodehelper_enable();
 	if (!initramfs_async)
 		wait_for_initramfs();
 	return 0;
 }
 rootfs_initcall(populate_rootfs);
	// SPDX-License-Identifier: GPL-2.0
	#include <linux/init.h>
	#include <linux/async.h>
	#include <linux/fs.h>
	#include <linux/slab.h>
	#include <linux/types.h>
	#include <linux/fcntl.h>
	#include <linux/delay.h>
	#include <linux/string.h>
	#include <linux/dirent.h>
	#include <linux/syscalls.h>
	#include <linux/utime.h>
	#include <linux/file.h>
	#include <linux/memblock.h>
	#include <linux/mm.h>
	#include <linux/namei.h>
	#include <linux/init_syscalls.h>
	#include <linux/umh.h>

	static ssize_t __init xwrite(struct file file, const char p, size_t count,
	loff_t *pos)
	{
	ssize_t out = 0;

	/* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
	while (count) {
	ssize_t rv = kernel_write(file, p, count, pos);

	if (rv < 0) {
	if (rv == -EINTR \|\| rv == -EAGAIN)
	continue;
	return out ? out : rv;
	} else if (rv == 0)
	break;

	p += rv;
	out += rv;
	count -= rv;
	}

	return out;
	}

	static __initdata char *message;
	static void __init error(char *x)
	{
	if (!message)
	message = x;
	}

	static void panic_show_mem(const char *fmt, ...)
	{
	va_list args;

	show_mem(0, NULL);
	va_start(args, fmt);
	panic(fmt, args);
	va_end(args);
	}

	/* link hash */

	#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)

	static __initdata struct hash {
	int ino, minor, major;
	umode_t mode;
	struct hash *next;
	char name[N_ALIGN(PATH_MAX)];
	} *head[32];

	static inline int hash(int major, int minor, int ino)
	{
	unsigned long tmp = ino + minor + (major << 3);
	tmp += tmp >> 5;
	return tmp & 31;
	}

	static char __init *find_link(int major, int minor, int ino,
	umode_t mode, char *name)
	{
	struct hash *p, q;
	for (p = head + hash(major, minor, ino); p; p = &(p)->next) {
	if ((*p)->ino != ino)
	continue;
	if ((*p)->minor != minor)
	continue;
	if ((*p)->major != major)
	continue;
	if (((*p)->mode ^ mode) & S_IFMT)
	continue;
	return (*p)->name;
	}
	q = kmalloc(sizeof(struct hash), GFP_KERNEL);
	if (!q)
	panic_show_mem("can't allocate link hash entry");
	q->major = major;
	q->minor = minor;
	q->ino = ino;
	q->mode = mode;
	strcpy(q->name, name);
	q->next = NULL;
	*p = q;
	return NULL;
	}

	static void __init free_hash(void)
	{
	struct hash *p, q;
	for (p = head; p < head + 32; p++) {
	while (*p) {
	q = *p;
	*p = q->next;
	kfree(q);
	}
	}
	}

	static long __init do_utime(char *filename, time64_t mtime)
	{
	struct timespec64 t[2];

	t[0].tv_sec = mtime;
	t[0].tv_nsec = 0;
	t[1].tv_sec = mtime;
	t[1].tv_nsec = 0;
	return init_utimes(filename, t);
	}

	static __initdata LIST_HEAD(dir_list);
	struct dir_entry {
	struct list_head list;
	char *name;
	time64_t mtime;
	};

	static void __init dir_add(const char *name, time64_t mtime)
	{
	struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
	if (!de)
	panic_show_mem("can't allocate dir_entry buffer");
	INIT_LIST_HEAD(&de->list);
	de->name = kstrdup(name, GFP_KERNEL);
	de->mtime = mtime;
	list_add(&de->list, &dir_list);
	}

	static void __init dir_utime(void)
	{
	struct dir_entry de, tmp;
	list_for_each_entry_safe(de, tmp, &dir_list, list) {
	list_del(&de->list);
	do_utime(de->name, de->mtime);
	kfree(de->name);
	kfree(de);
	}
	}

	static __initdata time64_t mtime;

	/* cpio header parsing */

	static __initdata unsigned long ino, major, minor, nlink;
	static __initdata umode_t mode;
	static __initdata unsigned long body_len, name_len;
	static __initdata uid_t uid;
	static __initdata gid_t gid;
	static __initdata unsigned rdev;

	static void __init parse_header(char *s)
	{
	unsigned long parsed[12];
	char buf[9];
	int i;

	buf[8] = '\0';
	for (i = 0, s += 6; i < 12; i++, s += 8) {
	memcpy(buf, s, 8);
	parsed[i] = simple_strtoul(buf, NULL, 16);
	}
	ino = parsed[0];
	mode = parsed[1];
	uid = parsed[2];
	gid = parsed[3];
	nlink = parsed[4];
	mtime = parsed[5]; /* breaks in y2106 */
	body_len = parsed[6];
	major = parsed[7];
	minor = parsed[8];
	rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
	name_len = parsed[11];
	}

	/* FSM */

	static __initdata enum state {
	Start,
	Collect,
	GotHeader,
	SkipIt,
	GotName,
	CopyFile,
	GotSymlink,
	Reset
	} state, next_state;

	static __initdata char *victim;
	static unsigned long byte_count __initdata;
	static __initdata loff_t this_header, next_header;

	static inline void __init eat(unsigned n)
	{
	victim += n;
	this_header += n;
	byte_count -= n;
	}

	static __initdata char *collected;
	static long remains __initdata;
	static __initdata char *collect;

	static void __init read_into(char *buf, unsigned size, enum state next)
	{
	if (byte_count >= size) {
	collected = victim;
	eat(size);
	state = next;
	} else {
	collect = collected = buf;
	remains = size;
	next_state = next;
	state = Collect;
	}
	}

	static __initdata char header_buf, symlink_buf, *name_buf;

	static int __init do_start(void)
	{
	read_into(header_buf, 110, GotHeader);
	return 0;
	}

	static int __init do_collect(void)
	{
	unsigned long n = remains;
	if (byte_count < n)
	n = byte_count;
	memcpy(collect, victim, n);
	eat(n);
	collect += n;
	if ((remains -= n) != 0)
	return 1;
	state = next_state;
	return 0;
	}

	static int __init do_header(void)
	{
	if (memcmp(collected, "070707", 6)==0) {
	error("incorrect cpio method used: use -H newc option");
	return 1;
	}
	if (memcmp(collected, "070701", 6)) {
	error("no cpio magic");
	return 1;
	}
	parse_header(collected);
	next_header = this_header + N_ALIGN(name_len) + body_len;
	next_header = (next_header + 3) & ~3;
	state = SkipIt;
	if (name_len <= 0 \|\| name_len > PATH_MAX)
	return 0;
	if (S_ISLNK(mode)) {
	if (body_len > PATH_MAX)
	return 0;
	collect = collected = symlink_buf;
	remains = N_ALIGN(name_len) + body_len;
	next_state = GotSymlink;
	state = Collect;
	return 0;
	}
	if (S_ISREG(mode) \|\| !body_len)
	read_into(name_buf, N_ALIGN(name_len), GotName);
	return 0;
	}

	static int __init do_skip(void)
	{
	if (this_header + byte_count < next_header) {
	eat(byte_count);
	return 1;
	} else {
	eat(next_header - this_header);
	state = next_state;
	return 0;
	}
	}

	static int __init do_reset(void)
	{
	while (byte_count && *victim == '\0')
	eat(1);
	if (byte_count && (this_header & 3))
	error("broken padding");
	return 1;
	}

	static void __init clean_path(char *path, umode_t fmode)
	{
	struct kstat st;

	if (!init_stat(path, &st, AT_SYMLINK_NOFOLLOW) &&
	(st.mode ^ fmode) & S_IFMT) {
	if (S_ISDIR(st.mode))
	init_rmdir(path);
	else
	init_unlink(path);
	}
	}

	static int __init maybe_link(void)
	{
	if (nlink >= 2) {
	char *old = find_link(major, minor, ino, mode, collected);
	if (old) {
	clean_path(collected, 0);
	return (init_link(old, collected) < 0) ? -1 : 1;
	}
	}
	return 0;
	}

	static __initdata struct file *wfile;
	static __initdata loff_t wfile_pos;

	static int __init do_name(void)
	{
	state = SkipIt;
	next_state = Reset;

	/* name_len > 0 && name_len <= PATH_MAX checked in do_header */
	if (collected[name_len - 1] != '\0') {
	pr_err("initramfs name without nulterm: %.*s\n",
	(int)name_len, collected);
	error("malformed archive");
	return 1;
	}

	if (strcmp(collected, "TRAILER!!!") == 0) {
	free_hash();
	return 0;
	}
	clean_path(collected, mode);
	if (S_ISREG(mode)) {
	int ml = maybe_link();
	if (ml >= 0) {
	int openflags = O_WRONLY\|O_CREAT;
	if (ml != 1)
	openflags \|= O_TRUNC;
	wfile = filp_open(collected, openflags, mode);
	if (IS_ERR(wfile))
	return 0;
	wfile_pos = 0;

	vfs_fchown(wfile, uid, gid);
	vfs_fchmod(wfile, mode);
	if (body_len)
	vfs_truncate(&wfile->f_path, body_len);
	state = CopyFile;
	}
	} else if (S_ISDIR(mode)) {
	init_mkdir(collected, mode);
	init_chown(collected, uid, gid, 0);
	init_chmod(collected, mode);
	dir_add(collected, mtime);
	} else if (S_ISBLK(mode) \|\| S_ISCHR(mode) \|\|
	S_ISFIFO(mode) \|\| S_ISSOCK(mode)) {
	if (maybe_link() == 0) {
	init_mknod(collected, mode, rdev);
	init_chown(collected, uid, gid, 0);
	init_chmod(collected, mode);
	do_utime(collected, mtime);
	}
	}
	return 0;
	}

	static int __init do_copy(void)
	{
	if (byte_count >= body_len) {
	struct timespec64 t[2] = { };
	if (xwrite(wfile, victim, body_len, &wfile_pos) != body_len)
	error("write error");

	t[0].tv_sec = mtime;
	t[1].tv_sec = mtime;
	vfs_utimes(&wfile->f_path, t);

	fput(wfile);
	eat(body_len);
	state = SkipIt;
	return 0;
	} else {
	if (xwrite(wfile, victim, byte_count, &wfile_pos) != byte_count)
	error("write error");
	body_len -= byte_count;
	eat(byte_count);
	return 1;
	}
	}

	static int __init do_symlink(void)
	{
	if (collected[name_len - 1] != '\0') {
	pr_err("initramfs symlink without nulterm: %.*s\n",
	(int)name_len, collected);
	error("malformed archive");
	return 1;
	}
	collected[N_ALIGN(name_len) + body_len] = '\0';
	clean_path(collected, 0);
	init_symlink(collected + N_ALIGN(name_len), collected);
	init_chown(collected, uid, gid, AT_SYMLINK_NOFOLLOW);
	do_utime(collected, mtime);
	state = SkipIt;
	next_state = Reset;
	return 0;
	}

	static __initdata int (*actions[])(void) = {
	[Start] = do_start,
	[Collect] = do_collect,
	[GotHeader] = do_header,
	[SkipIt] = do_skip,
	[GotName] = do_name,
	[CopyFile] = do_copy,
	[GotSymlink] = do_symlink,
	[Reset] = do_reset,
	};

	static long __init write_buffer(char *buf, unsigned long len)
	{
	byte_count = len;
	victim = buf;

	while (!actions[state]())
	;
	return len - byte_count;
	}

	static long __init flush_buffer(void *bufv, unsigned long len)
	{
	char buf = (char ) bufv;
	long written;
	long origLen = len;
	if (message)
	return -1;
	while ((written = write_buffer(buf, len)) < len && !message) {
	char c = buf[written];
	if (c == '0') {
	buf += written;
	len -= written;
	state = Start;
	} else if (c == 0) {
	buf += written;
	len -= written;
	state = Reset;
	} else
	error("junk within compressed archive");
	}
	return origLen;
	}

	static unsigned long my_inptr; /* index of next byte to be processed in inbuf */

	#include <linux/decompress/generic.h>

	static char * __init unpack_to_rootfs(char *buf, unsigned long len)
	{
	long written;
	decompress_fn decompress;
	const char *compress_name;
	static __initdata char msg_buf[64];

	header_buf = kmalloc(110, GFP_KERNEL);
	symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
	name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);

	if (!header_buf \|\| !symlink_buf \|\| !name_buf)
	panic_show_mem("can't allocate buffers");

	state = Start;
	this_header = 0;
	message = NULL;
	while (!message && len) {
	loff_t saved_offset = this_header;
	if (*buf == '0' && !(this_header & 3)) {
	state = Start;
	written = write_buffer(buf, len);
	buf += written;
	len -= written;
	continue;
	}
	if (!*buf) {
	buf++;
	len--;
	this_header++;
	continue;
	}
	this_header = 0;
	decompress = decompress_method(buf, len, &compress_name);
	pr_debug("Detected %s compressed data\n", compress_name);
	if (decompress) {
	int res = decompress(buf, len, NULL, flush_buffer, NULL,
	&my_inptr, error);
	if (res)
	error("decompressor failed");
	} else if (compress_name) {
	if (!message) {
	snprintf(msg_buf, sizeof msg_buf,
	"compression method %s not configured",
	compress_name);
	message = msg_buf;
	}
	} else
	error("invalid magic at start of compressed archive");
	if (state != Reset)
	error("junk at the end of compressed archive");
	this_header = saved_offset + my_inptr;
	buf += my_inptr;
	len -= my_inptr;
	}
	dir_utime();
	kfree(name_buf);
	kfree(symlink_buf);
	kfree(header_buf);
	return message;
	}

	static int __initdata do_retain_initrd;

	static int __init retain_initrd_param(char *str)
	{
	if (*str)
	return 0;
	do_retain_initrd = 1;
	return 1;
	}
	__setup("retain_initrd", retain_initrd_param);

	#ifdef CONFIG_ARCH_HAS_KEEPINITRD
	static int __init keepinitrd_setup(char *__unused)
	{
	do_retain_initrd = 1;
	return 1;
	}
	__setup("keepinitrd", keepinitrd_setup);
	#endif

	static bool __initdata initramfs_async = true;
	static int __init initramfs_async_setup(char *str)
	{
	strtobool(str, &initramfs_async);
	return 1;
	}
	__setup("initramfs_async=", initramfs_async_setup);

	extern char __initramfs_start[];
	extern unsigned long __initramfs_size;
	#include <linux/initrd.h>
	#include <linux/kexec.h>

	void __init reserve_initrd_mem(void)
	{
	phys_addr_t start;
	unsigned long size;

	/* Ignore the virtul address computed during device tree parsing */
	initrd_start = initrd_end = 0;

	if (!phys_initrd_size)
	return;
	/*
	* Round the memory region to page boundaries as per free_initrd_mem()
	* This allows us to detect whether the pages overlapping the initrd
	* are in use, but more importantly, reserves the entire set of pages
	* as we don't want these pages allocated for other purposes.
	*/
	start = round_down(phys_initrd_start, PAGE_SIZE);
	size = phys_initrd_size + (phys_initrd_start - start);
	size = round_up(size, PAGE_SIZE);

	if (!memblock_is_region_memory(start, size)) {
	pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
	(u64)start, size);
	goto disable;
	}

	if (memblock_is_region_reserved(start, size)) {
	pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
	(u64)start, size);
	goto disable;
	}

	memblock_reserve(start, size);
	/* Now convert initrd to virtual addresses */
	initrd_start = (unsigned long)__va(phys_initrd_start);
	initrd_end = initrd_start + phys_initrd_size;
	initrd_below_start_ok = 1;

	return;
	disable:
	pr_cont(" - disabling initrd\n");
	initrd_start = 0;
	initrd_end = 0;
	}

	void __weak __init free_initrd_mem(unsigned long start, unsigned long end)
	{
	#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
	unsigned long aligned_start = ALIGN_DOWN(start, PAGE_SIZE);
	unsigned long aligned_end = ALIGN(end, PAGE_SIZE);

	memblock_free(__pa(aligned_start), aligned_end - aligned_start);
	#endif

	free_reserved_area((void )start, (void )end, POISON_FREE_INITMEM,
	"initrd");
	}

	#ifdef CONFIG_KEXEC_CORE
	static bool __init kexec_free_initrd(void)
	{
	unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
	unsigned long crashk_end = (unsigned long)__va(crashk_res.end);

	/*
	* If the initrd region is overlapped with crashkernel reserved region,
	* free only memory that is not part of crashkernel region.
	*/
	if (initrd_start >= crashk_end \|\| initrd_end <= crashk_start)
	return false;

	/*
	* Initialize initrd memory region since the kexec boot does not do.
	*/
	memset((void *)initrd_start, 0, initrd_end - initrd_start);
	if (initrd_start < crashk_start)
	free_initrd_mem(initrd_start, crashk_start);
	if (initrd_end > crashk_end)
	free_initrd_mem(crashk_end, initrd_end);
	return true;
	}
	#else
	static inline bool kexec_free_initrd(void)
	{
	return false;
	}
	#endif /* CONFIG_KEXEC_CORE */

	#ifdef CONFIG_BLK_DEV_RAM
	static void __init populate_initrd_image(char *err)
	{
	ssize_t written;
	struct file *file;
	loff_t pos = 0;

	unpack_to_rootfs(__initramfs_start, __initramfs_size);

	printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
	err);
	file = filp_open("/initrd.image", O_WRONLY\|O_CREAT\|O_LARGEFILE, 0700);
	if (IS_ERR(file))
	return;

	written = xwrite(file, (char *)initrd_start, initrd_end - initrd_start,
	&pos);
	if (written != initrd_end - initrd_start)
	pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
	written, initrd_end - initrd_start);
	fput(file);
	}
	#endif /* CONFIG_BLK_DEV_RAM */

	static void __init do_populate_rootfs(void *unused, async_cookie_t cookie)
	{
	/* Load the built in initramfs */
	char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
	if (err)
	panic_show_mem("%s", err); /* Failed to decompress INTERNAL initramfs */

	if (!initrd_start \|\| IS_ENABLED(CONFIG_INITRAMFS_FORCE))
	goto done;

	if (IS_ENABLED(CONFIG_BLK_DEV_RAM))
	printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
	else
	printk(KERN_INFO "Unpacking initramfs...\n");

	err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start);
	if (err) {
	#ifdef CONFIG_BLK_DEV_RAM
	populate_initrd_image(err);
	#else
	printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
	#endif
	}

	done:
	/*
	* If the initrd region is overlapped with crashkernel reserved region,
	* free only memory that is not part of crashkernel region.
	*/
	if (!do_retain_initrd && initrd_start && !kexec_free_initrd())
	free_initrd_mem(initrd_start, initrd_end);
	initrd_start = 0;
	initrd_end = 0;

	flush_delayed_fput();
	}

	static ASYNC_DOMAIN_EXCLUSIVE(initramfs_domain);
	static async_cookie_t initramfs_cookie;

	void wait_for_initramfs(void)
	{
	if (!initramfs_cookie) {
	/*
	* Something before rootfs_initcall wants to access
	* the filesystem/initramfs. Probably a bug. Make a
	* note, avoid deadlocking the machine, and let the
	* caller's access fail as it used to.
	*/
	pr_warn_once("wait_for_initramfs() called before rootfs_initcalls\n");
	return;
	}
	async_synchronize_cookie_domain(initramfs_cookie + 1, &initramfs_domain);
	}
	EXPORT_SYMBOL_GPL(wait_for_initramfs);

	static int __init populate_rootfs(void)
	{
	initramfs_cookie = async_schedule_domain(do_populate_rootfs, NULL,
	&initramfs_domain);
	usermodehelper_enable();
	if (!initramfs_async)
	wait_for_initramfs();
	return 0;
	}
	rootfs_initcall(populate_rootfs);