bug-link-o-tmpfile.c

 1/*
 2 * Copyright (c) 2019 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(O_TMPFILE), linkat() doesn't screw accounting. */
17#include <errno.h>
18#include <sched.h>
19#include <stdio.h>
20#include <sys/types.h>
21#include <sys/stat.h>
22#include <fcntl.h>
23#include <sys/mount.h>
24#include <unistd.h>
25
26#include "kselftest.h"
27
28int main(void)
29{
30	int fd;
31
32	// Setting up kselftest framework
33	ksft_print_header();
34	ksft_set_plan(1);
35
36	// Check if test is run as root
37	if (geteuid()) {
38		ksft_exit_skip("This test needs root to run!\n");
39		return 1;
40	}
41
42	if (unshare(CLONE_NEWNS) == -1) {
43		if (errno == ENOSYS || errno == EPERM) {
44			ksft_exit_skip("unshare() error: unshare, errno %d\n", errno);
45		} else {
46			ksft_exit_fail_msg("unshare() error: unshare, errno %d\n", errno);
47		}
48	}
49
50	if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
51		ksft_exit_fail_msg("mount() error: Root filesystem private mount: Fail %d\n", errno);
52	}
53
54	/* Our heroes: 1 root inode, 1 O_TMPFILE inode, 1 permanent inode. */
55	if (mount(NULL, "/tmp", "tmpfs", 0, "nr_inodes=3") == -1) {
56		ksft_exit_fail_msg("mount() error: Mounting tmpfs on /tmp: Fail %d\n", errno);
57	}
58
59	fd = openat(AT_FDCWD, "/tmp", O_WRONLY|O_TMPFILE, 0600);
60	if (fd == -1) {
61		ksft_exit_fail_msg("openat() error: Open first temporary file: Fail %d\n", errno);
62	}
63
64	if (linkat(fd, "", AT_FDCWD, "/tmp/1", AT_EMPTY_PATH) == -1) {
65		ksft_exit_fail_msg("linkat() error: Linking the temporary file: Fail %d\n", errno);
66		/* Ensure fd is closed on failure */
67		close(fd);
68	}
69	close(fd);
70
71	fd = openat(AT_FDCWD, "/tmp", O_WRONLY|O_TMPFILE, 0600);
72	if (fd == -1) {
73		ksft_exit_fail_msg("openat() error: Opening the second temporary file: Fail %d\n", errno);
74	}
75	ksft_test_result_pass(" ");
76	ksft_exit_pass();
77	return 0;
78}