selftests/proc/proc-self-wchan.c

0001 /*
0002  * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
0003  *
0004  * Permission to use, copy, modify, and distribute this software for any
0005  * purpose with or without fee is hereby granted, provided that the above
0006  * copyright notice and this permission notice appear in all copies.
0007  *
0008  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
0009  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
0010  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
0011  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
0012  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
0013  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
0014  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
0015  */
0016 #include <sys/types.h>
0017 #include <sys/stat.h>
0018 #include <fcntl.h>
0019 #include <errno.h>
0020 #include <unistd.h>
0021
0022 int main(void)
0023 {
0024     char buf[64];
0025     int fd;
0026
0027     fd = open("/proc/self/wchan", O_RDONLY);
0028     if (fd == -1) {
0029         if (errno == ENOENT)
0030             return 4;
0031         return 1;
0032     }
0033
0034     buf[0] = '\0';
0035     if (read(fd, buf, sizeof(buf)) != 1)
0036         return 1;
0037     if (buf[0] != '0')
0038         return 1;
0039     return 0;
0040 }