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 /* Test that /proc/loadavg correctly reports last pid in pid namespace. */
17 #define _GNU_SOURCE
18 #include <errno.h>
19 #include <sched.h>
20 #include <sys/types.h>
21 #include <sys/stat.h>
22 #include <fcntl.h>
23 #include <unistd.h>
24 #include <sys/wait.h>
25
26 int main(void)
27 {
28 pid_t pid;
29 int wstatus;
30
31 if (unshare(CLONE_NEWPID) == -1) {
32 if (errno == ENOSYS || errno == EPERM)
33 return 4;
34 return 1;
35 }
36
37 pid = fork();
38 if (pid == -1)
39 return 1;
40 if (pid == 0) {
41 char buf[128], *p;
42 int fd;
43 ssize_t rv;
44
45 fd = open("/proc/loadavg" , O_RDONLY);
46 if (fd == -1)
47 return 1;
48 rv = read(fd, buf, sizeof(buf));
49 if (rv < 3)
50 return 1;
51 p = buf + rv;
52
53 /* pid 1 */
54 if (!(p[-3] == ' ' && p[-2] == '1' && p[-1] == '\n'))
55 return 1;
56
57 pid = fork();
58 if (pid == -1)
59 return 1;
60 if (pid == 0)
61 return 0;
62 if (waitpid(pid, NULL, 0) == -1)
63 return 1;
64
65 lseek(fd, 0, SEEK_SET);
66 rv = read(fd, buf, sizeof(buf));
67 if (rv < 3)
68 return 1;
69 p = buf + rv;
70
71 /* pid 2 */
72 if (!(p[-3] == ' ' && p[-2] == '2' && p[-1] == '\n'))
73 return 1;
74
75 return 0;
76 }
77
78 if (waitpid(pid, &wstatus, 0) == -1)
79 return 1;
80 if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0)
81 return 0;
82 return 1;
83 }