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 * and returns:
23 * -> 2 if fork fails with EAGAIN,
24 * -> 1 if there is another problem
25 * -> 0 if everything worked
26 */
27
28 #include <sys/types.h>
29 #include <stdio.h>
30 #include <unistd.h>
31 #include <errno.h>
32
main(int argc,char ** argv)33 int main(int argc, char **argv)
34 {
35 FILE *f;
36 int newpid;
37
38 if (argc != 2) {
39 fprintf(stderr, "Usage: %s /cgroup/.../tasks\n", argv[0]);
40 return 1;
41 }
42
43 f = fopen(argv[1], "a");
44 if (!f) {
45 perror("fopen failed");
46 return 1;
47 }
48
49 fprintf(f, "%i\n", getpid());
50 fclose(f);
51
52 newpid = fork();
53 if (newpid == -1 && errno == EAGAIN)
54 return 2;
55 if (newpid == -1) {
56 perror("fork() failed");
57 return 1;
58 }
59 return 0;
60 }
61