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
  22 int 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 }