linux/tools/testing/selftests/tmpfs/bug-link-o-tmpfile.c

68 lines
2.0 KiB
C

/*
* Copyright (c) 2019 Alexey Dobriyan <adobriyan@gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* Test that open(O_TMPFILE), linkat() doesn't screw accounting. */
#include <errno.h>
#include <sched.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mount.h>
#include <unistd.h>
int main(void)
{
int fd;
if (unshare(CLONE_NEWNS) == -1) {
if (errno == ENOSYS || errno == EPERM) {
fprintf(stderr, "error: unshare, errno %d\n", errno);
return 4;
}
fprintf(stderr, "error: unshare, errno %d\n", errno);
return 1;
}
if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
fprintf(stderr, "error: mount '/', errno %d\n", errno);
return 1;
}
/* Our heroes: 1 root inode, 1 O_TMPFILE inode, 1 permanent inode. */
if (mount(NULL, "/tmp", "tmpfs", 0, "nr_inodes=3") == -1) {
fprintf(stderr, "error: mount tmpfs, errno %d\n", errno);
return 1;
}
fd = openat(AT_FDCWD, "/tmp", O_WRONLY|O_TMPFILE, 0600);
if (fd == -1) {
fprintf(stderr, "error: open 1, errno %d\n", errno);
return 1;
}
if (linkat(fd, "", AT_FDCWD, "/tmp/1", AT_EMPTY_PATH) == -1) {
fprintf(stderr, "error: linkat, errno %d\n", errno);
return 1;
}
close(fd);
fd = openat(AT_FDCWD, "/tmp", O_WRONLY|O_TMPFILE, 0600);
if (fd == -1) {
fprintf(stderr, "error: open 2, errno %d\n", errno);
return 1;
}
return 0;
}