LXR linux/tools/testing/selftests/proc/proc-self-wchan.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#include <sys/types.h>
  17#include <sys/stat.h>
  18#include <fcntl.h>
  19#include <errno.h>
  20#include <unistd.h>
  21
  22int main(void)
  23{
  24        char buf[64];
  25        int fd;
  26
  27        fd = open("/proc/self/wchan", O_RDONLY);
  28        if (fd == -1) {
  29                if (errno == ENOENT)
  30                        return 4;
  31                return 1;
  32        }
  33
  34        buf[0] = '\0';
  35        if (read(fd, buf, sizeof(buf)) != 1)
  36                return 1;
  37        if (buf[0] != '0')
  38                return 1;
  39        return 0;
  40}
  41