LXR linux/tools/testing/selftests/proc/thread-self.c

   1/*
   2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
   3 *
   4 * Permission to use, copy, modify, and distribute this software for any
   5 * purpose with or without fee is hereby granted, provided that the above
   6 * copyright notice and this permission notice appear in all copies.
   7 *
   8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15 */
  16// Test that /proc/thread-self gives correct TGID/PID.
  17#undef NDEBUG
  18#include <assert.h>
  19#include <sched.h>
  20#include <stdio.h>
  21#include <unistd.h>
  22#include <sys/mman.h>
  23#include <sys/wait.h>
  24
  25#include "proc.h"
  26
  27int f(void *arg)
  28{
  29        char buf1[64], buf2[64];
  30        pid_t pid, tid;
  31        ssize_t rv;
  32
  33        pid = sys_getpid();
  34        tid = sys_gettid();
  35        snprintf(buf1, sizeof(buf1), "%u/task/%u", pid, tid);
  36
  37        rv = readlink("/proc/thread-self", buf2, sizeof(buf2));
  38        assert(rv == strlen(buf1));
  39        buf2[rv] = '\0';
  40        assert(streq(buf1, buf2));
  41
  42        if (arg)
  43                exit(0);
  44        return 0;
  45}
  46
  47int main(void)
  48{
  49        const int PAGE_SIZE = sysconf(_SC_PAGESIZE);
  50        pid_t pid;
  51        void *stack;
  52
  53        /* main thread */
  54        f((void *)0);
  55
  56        stack = mmap(NULL, 2 * PAGE_SIZE, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
  57        assert(stack != MAP_FAILED);
  58        /* side thread */
  59        pid = clone(f, stack + PAGE_SIZE, CLONE_THREAD|CLONE_SIGHAND|CLONE_VM, (void *)1);
  60        assert(pid > 0);
  61        pause();
  62
  63        return 0;
  64}
  65