xref: /linux/tools/testing/selftests/proc/fd-002-posix-eq.c (revision 95298d63c67673c654c08952672d016212b26054)
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 open(/proc/*/fd/*) opens the same file.
17 #undef NDEBUG
18 #include <assert.h>
19 #include <stdio.h>
20 #include <sys/types.h>
21 #include <sys/stat.h>
22 #include <fcntl.h>
23 #include <unistd.h>
24 
25 int main(void)
26 {
27 	int fd0, fd1, fd2;
28 	struct stat st0, st1, st2;
29 	char buf[64];
30 	int rv;
31 
32 	fd0 = open("/", O_DIRECTORY|O_RDONLY);
33 	assert(fd0 >= 0);
34 
35 	snprintf(buf, sizeof(buf), "/proc/self/fd/%u", fd0);
36 	fd1 = open(buf, O_RDONLY);
37 	assert(fd1 >= 0);
38 
39 	snprintf(buf, sizeof(buf), "/proc/thread-self/fd/%u", fd0);
40 	fd2 = open(buf, O_RDONLY);
41 	assert(fd2 >= 0);
42 
43 	rv = fstat(fd0, &st0);
44 	assert(rv == 0);
45 	rv = fstat(fd1, &st1);
46 	assert(rv == 0);
47 	rv = fstat(fd2, &st2);
48 	assert(rv == 0);
49 
50 	assert(st0.st_dev == st1.st_dev);
51 	assert(st0.st_ino == st1.st_ino);
52 
53 	assert(st0.st_dev == st2.st_dev);
54 	assert(st0.st_ino == st2.st_ino);
55 
56 	return 0;
57 }
58