1 /*
2 * Copyright (c) 2015 Cedric Hnyda <chnyda@suse.com>
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of
7 * the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 /*
20 * Description:
21 * Write the current process in argv[1]
22 */
23
24 #include <stdio.h>
25 #include <sys/time.h>
26 #include <sys/types.h>
27 #include <unistd.h>
28 #include <signal.h>
29 #include <stdlib.h>
30 #include <string.h>
31
sig_handler(int signo)32 static void sig_handler(int signo)
33 {
34 _exit(0);
35 }
36
main(int argc,char ** argv)37 int main(int argc, char **argv)
38 {
39 FILE *f;
40 struct sigaction sa;
41
42 if (argc != 2) {
43 fprintf(stderr, "Usage: %s /cgroup/.../tasks\n", argv[0]);
44 return 1;
45 }
46
47 f = fopen(argv[1], "a");
48 if (!f) {
49 perror("fopen failed");
50 return 1;
51 }
52
53 fprintf(f, "%i\n", getpid());
54 fclose(f);
55
56 memset(&sa, 0, sizeof(sa));
57 sigemptyset(&sa.sa_mask);
58 sa.sa_handler = sig_handler;
59
60 if (sigaction(SIGVTALRM, &sa, NULL)) {
61 perror("sigaction failed");
62 return 1;
63 }
64
65 struct itimerval it = {.it_value = {.tv_sec = 0, .tv_usec = 10000}};
66
67 setitimer(ITIMER_VIRTUAL, &it, NULL);
68 for (;;);
69 return 0;
70 }
71