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 int main(void)
27 {
28 	int fd;
29 
30 	if (unshare(CLONE_NEWNS) == -1) {
31 		if (errno == ENOSYS || errno == EPERM) {
32 			fprintf(stderr, "error: unshare, errno %d\n", errno);
33 			return 4;
34 		}
35 		fprintf(stderr, "error: unshare, errno %d\n", errno);
36 		return 1;
37 	}
38 	if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
39 		fprintf(stderr, "error: mount '/', errno %d\n", errno);
40 		return 1;
41 	}
42 
43 	/* Our heroes: 1 root inode, 1 O_TMPFILE inode, 1 permanent inode. */
44 	if (mount(NULL, "/tmp", "tmpfs", 0, "nr_inodes=3") == -1) {
45 		fprintf(stderr, "error: mount tmpfs, errno %d\n", errno);
46 		return 1;
47 	}
48 
49 	fd = openat(AT_FDCWD, "/tmp", O_WRONLY|O_TMPFILE, 0600);
50 	if (fd == -1) {
51 		fprintf(stderr, "error: open 1, errno %d\n", errno);
52 		return 1;
53 	}
54 	if (linkat(fd, "", AT_FDCWD, "/tmp/1", AT_EMPTY_PATH) == -1) {
55 		fprintf(stderr, "error: linkat, errno %d\n", errno);
56 		return 1;
57 	}
58 	close(fd);
59 
60 	fd = openat(AT_FDCWD, "/tmp", O_WRONLY|O_TMPFILE, 0600);
61 	if (fd == -1) {
62 		fprintf(stderr, "error: open 2, errno %d\n", errno);
63 		return 1;
64 	}
65 
66 	return 0;
67 }
68