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