1/*
2 * Copyright © 2020 Alexey Gladkov <gladkov.alexey@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#include <assert.h>
17#include <stdlib.h>
18#include <stdio.h>
19#include <sys/mount.h>
20#include <sys/types.h>
21#include <sys/stat.h>
22
23int main(void)
24{
25 struct stat proc_st1, proc_st2;
26 char procbuff[] = "/tmp/proc.XXXXXX/meminfo";
27 char procdir1[] = "/tmp/proc.XXXXXX";
28 char procdir2[] = "/tmp/proc.XXXXXX";
29
30 assert(mkdtemp(procdir1) != NULL);
31 assert(mkdtemp(procdir2) != NULL);
32
33 assert(!mount("proc", procdir1, "proc", 0, "hidepid=1"));
34 assert(!mount("proc", procdir2, "proc", 0, "hidepid=2"));
35
36 snprintf(procbuff, sizeof(procbuff), "%s/meminfo", procdir1);
37 assert(!stat(procbuff, &proc_st1));
38
39 snprintf(procbuff, sizeof(procbuff), "%s/meminfo", procdir2);
40 assert(!stat(procbuff, &proc_st2));
41
42 umount(procdir1);
43 umount(procdir2);
44
45 assert(proc_st1.st_dev != proc_st2.st_dev);
46
47 return 0;
48}
49

source code of linux/tools/testing/selftests/proc/proc-multiple-procfs.c