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
25int 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