| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 2021 VMware Inc, Steven Rostedt <rostedt@goodmis.org> |
| */ |
| #include <linux/vmalloc.h> |
| #include <linux/slab.h> |
| #include "trace.h" |
| |
| /** |
| * trace_pid_list_is_set - test if the pid is set in the list |
| * @pid_list: The pid list to test |
| * @pid: The pid to to see if set in the list. |
| * |
| * Tests if @pid is is set in the @pid_list. This is usually called |
| * from the scheduler when a task is scheduled. Its pid is checked |
| * if it should be traced or not. |
| * |
| * Return true if the pid is in the list, false otherwise. |
| */ |
| bool trace_pid_list_is_set(struct trace_pid_list *pid_list, unsigned int pid) |
| { |
| /* |
| * If pid_max changed after filtered_pids was created, we |
| * by default ignore all pids greater than the previous pid_max. |
| */ |
| if (pid >= pid_list->pid_max) |
| return false; |
| |
| return test_bit(pid, pid_list->pids); |
| } |
| |
| /** |
| * trace_pid_list_set - add a pid to the list |
| * @pid_list: The pid list to add the @pid to. |
| * @pid: The pid to add. |
| * |
| * Adds @pid to @pid_list. This is usually done explicitly by a user |
| * adding a task to be traced, or indirectly by the fork function |
| * when children should be traced and a task's pid is in the list. |
| * |
| * Return 0 on success, negative otherwise. |
| */ |
| int trace_pid_list_set(struct trace_pid_list *pid_list, unsigned int pid) |
| { |
| /* Sorry, but we don't support pid_max changing after setting */ |
| if (pid >= pid_list->pid_max) |
| return -EINVAL; |
| |
| set_bit(pid, pid_list->pids); |
| |
| return 0; |
| } |
| |
| /** |
| * trace_pid_list_clear - remove a pid from the list |
| * @pid_list: The pid list to remove the @pid from. |
| * @pid: The pid to remove. |
| * |
| * Removes @pid from @pid_list. This is usually done explicitly by a user |
| * removing tasks from tracing, or indirectly by the exit function |
| * when a task that is set to be traced exits. |
| * |
| * Return 0 on success, negative otherwise. |
| */ |
| int trace_pid_list_clear(struct trace_pid_list *pid_list, unsigned int pid) |
| { |
| /* Sorry, but we don't support pid_max changing after setting */ |
| if (pid >= pid_list->pid_max) |
| return -EINVAL; |
| |
| clear_bit(pid, pid_list->pids); |
| |
| return 0; |
| } |
| |
| /** |
| * trace_pid_list_next - return the next pid in the list |
| * @pid_list: The pid list to examine. |
| * @pid: The pid to start from |
| * @next: The pointer to place the pid that is set starting from @pid. |
| * |
| * Looks for the next consecutive pid that is in @pid_list starting |
| * at the pid specified by @pid. If one is set (including @pid), then |
| * that pid is placed into @next. |
| * |
| * Return 0 when a pid is found, -1 if there are no more pids included. |
| */ |
| int trace_pid_list_next(struct trace_pid_list *pid_list, unsigned int pid, |
| unsigned int *next) |
| { |
| pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid); |
| |
| if (pid < pid_list->pid_max) { |
| *next = pid; |
| return 0; |
| } |
| return -1; |
| } |
| |
| /** |
| * trace_pid_list_first - return the first pid in the list |
| * @pid_list: The pid list to examine. |
| * @pid: The pointer to place the pid first found pid that is set. |
| * |
| * Looks for the first pid that is set in @pid_list, and places it |
| * into @pid if found. |
| * |
| * Return 0 when a pid is found, -1 if there are no pids set. |
| */ |
| int trace_pid_list_first(struct trace_pid_list *pid_list, unsigned int *pid) |
| { |
| unsigned int first; |
| |
| first = find_first_bit(pid_list->pids, pid_list->pid_max); |
| |
| if (first < pid_list->pid_max) { |
| *pid = first; |
| return 0; |
| } |
| return -1; |
| } |
| |
| /** |
| * trace_pid_list_alloc - create a new pid_list |
| * |
| * Allocates a new pid_list to store pids into. |
| * |
| * Returns the pid_list on success, NULL otherwise. |
| */ |
| struct trace_pid_list *trace_pid_list_alloc(void) |
| { |
| struct trace_pid_list *pid_list; |
| |
| pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL); |
| if (!pid_list) |
| return NULL; |
| |
| pid_list->pid_max = READ_ONCE(pid_max); |
| |
| pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3); |
| if (!pid_list->pids) { |
| kfree(pid_list); |
| return NULL; |
| } |
| return pid_list; |
| } |
| |
| /** |
| * trace_pid_list_free - Frees an allocated pid_list. |
| * |
| * Frees the memory for a pid_list that was allocated. |
| */ |
| void trace_pid_list_free(struct trace_pid_list *pid_list) |
| { |
| if (!pid_list) |
| return; |
| |
| vfree(pid_list->pids); |
| kfree(pid_list); |
| } |