1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * Permission to use, copy, modify, and distribute this software for any
5*4882a593Smuzhiyun * purpose with or without fee is hereby granted, provided that the above
6*4882a593Smuzhiyun * copyright notice and this permission notice appear in all copies.
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9*4882a593Smuzhiyun * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10*4882a593Smuzhiyun * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11*4882a593Smuzhiyun * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12*4882a593Smuzhiyun * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13*4882a593Smuzhiyun * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14*4882a593Smuzhiyun * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15*4882a593Smuzhiyun */
16*4882a593Smuzhiyun #include <sys/types.h>
17*4882a593Smuzhiyun #include <sys/stat.h>
18*4882a593Smuzhiyun #include <fcntl.h>
19*4882a593Smuzhiyun #include <errno.h>
20*4882a593Smuzhiyun #include <unistd.h>
21*4882a593Smuzhiyun
main(void)22*4882a593Smuzhiyun int main(void)
23*4882a593Smuzhiyun {
24*4882a593Smuzhiyun char buf[64];
25*4882a593Smuzhiyun int fd;
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun fd = open("/proc/self/wchan", O_RDONLY);
28*4882a593Smuzhiyun if (fd == -1) {
29*4882a593Smuzhiyun if (errno == ENOENT)
30*4882a593Smuzhiyun return 4;
31*4882a593Smuzhiyun return 1;
32*4882a593Smuzhiyun }
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun buf[0] = '\0';
35*4882a593Smuzhiyun if (read(fd, buf, sizeof(buf)) != 1)
36*4882a593Smuzhiyun return 1;
37*4882a593Smuzhiyun if (buf[0] != '0')
38*4882a593Smuzhiyun return 1;
39*4882a593Smuzhiyun return 0;
40*4882a593Smuzhiyun }
41