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Merge pull request #122 from martinpitt/master

path-util: Fix path_is_mount_point for parent mount points in symlink mode
This commit is contained in:
Lennart Poettering 2015-06-09 20:06:02 +02:00
commit 135d5bfcae
2 changed files with 92 additions and 5 deletions

View File

@ -640,7 +640,7 @@ fallback_fstat:
/* flags can be AT_SYMLINK_FOLLOW or 0 */
int path_is_mount_point(const char *t, int flags) {
_cleanup_close_ int fd = -1;
_cleanup_free_ char *parent = NULL;
_cleanup_free_ char *canonical = NULL, *parent = NULL;
int r;
assert(t);
@ -648,7 +648,17 @@ int path_is_mount_point(const char *t, int flags) {
if (path_equal(t, "/"))
return 1;
r = path_get_parent(t, &parent);
/* we need to resolve symlinks manually, we can't just rely on
* fd_is_mount_point() to do that for us; if we have a structure like
* /bin -> /usr/bin/ and /usr is a mount point, then the parent that we
* look at needs to be /usr, not /. */
if (flags & AT_SYMLINK_FOLLOW) {
canonical = canonicalize_file_name(t);
if (!canonical)
return -errno;
}
r = path_get_parent(canonical ?: t, &parent);
if (r < 0)
return r;
@ -656,7 +666,7 @@ int path_is_mount_point(const char *t, int flags) {
if (fd < 0)
return -errno;
return fd_is_mount_point(fd, basename(t), flags);
return fd_is_mount_point(fd, basename(canonical ?: t), flags);
}
int path_is_read_only_fs(const char *path) {

View File

@ -312,9 +312,11 @@ static void test_prefix_root(void) {
}
static void test_path_is_mount_point(void) {
int fd, rt, rf, rlt, rlf;
int fd;
char tmp_dir[] = "/tmp/test-path-is-mount-point-XXXXXX";
_cleanup_free_ char *file1 = NULL, *file2 = NULL, *link1 = NULL, *link2 = NULL;
_cleanup_free_ char *dir1 = NULL, *dir1file = NULL, *dirlink1 = NULL, *dirlink1file = NULL;
_cleanup_free_ char *dir2 = NULL, *dir2file = NULL;
assert_se(path_is_mount_point("/", AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/", 0) > 0);
@ -328,6 +330,19 @@ static void test_path_is_mount_point(void) {
assert_se(path_is_mount_point("/sys", AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/sys", 0) > 0);
/* we'll create a hierarchy of different kinds of dir/file/link
* layouts:
*
* <tmp>/file1, <tmp>/file2
* <tmp>/link1 -> file1, <tmp>/link2 -> file2
* <tmp>/dir1/
* <tmp>/dir1/file
* <tmp>/dirlink1 -> dir1
* <tmp>/dirlink1file -> dirlink1/file
* <tmp>/dir2/
* <tmp>/dir2/file
*/
/* file mountpoints */
assert_se(mkdtemp(tmp_dir) != NULL);
file1 = path_join(NULL, tmp_dir, "file1");
@ -352,8 +367,43 @@ static void test_path_is_mount_point(void) {
assert_se(path_is_mount_point(link1, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(link1, 0) == 0);
/* this test will only work as root */
/* directory mountpoints */
dir1 = path_join(NULL, tmp_dir, "dir1");
assert_se(dir1);
assert_se(mkdir(dir1, 0755) == 0);
dirlink1 = path_join(NULL, tmp_dir, "dirlink1");
assert_se(dirlink1);
assert_se(symlink("dir1", dirlink1) == 0);
dirlink1file = path_join(NULL, tmp_dir, "dirlink1file");
assert_se(dirlink1file);
assert_se(symlink("dirlink1/file", dirlink1file) == 0);
dir2 = path_join(NULL, tmp_dir, "dir2");
assert_se(dir2);
assert_se(mkdir(dir2, 0755) == 0);
assert_se(path_is_mount_point(dir1, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dir1, 0) == 0);
assert_se(path_is_mount_point(dirlink1, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dirlink1, 0) == 0);
/* file in subdirectory mountpoints */
dir1file = path_join(NULL, dir1, "file");
assert_se(dir1file);
fd = open(dir1file, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
assert_se(fd > 0);
close(fd);
assert_se(path_is_mount_point(dir1file, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dir1file, 0) == 0);
assert_se(path_is_mount_point(dirlink1file, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dirlink1file, 0) == 0);
/* these tests will only work as root */
if (mount(file1, file2, NULL, MS_BIND, NULL) >= 0) {
int rt, rf, rlt, rlf, rl1t, rl1f;
/* files */
/* capture results in vars, to avoid dangling mounts on failure */
rf = path_is_mount_point(file2, 0);
rt = path_is_mount_point(file2, AT_SYMLINK_FOLLOW);
rlf = path_is_mount_point(link2, 0);
@ -365,6 +415,33 @@ static void test_path_is_mount_point(void) {
assert_se(rt == 1);
assert_se(rlf == 0);
assert_se(rlt == 1);
/* dirs */
dir2file = path_join(NULL, dir2, "file");
assert_se(dir2file);
fd = open(dir2file, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
assert_se(fd > 0);
close(fd);
assert_se(mount(dir2, dir1, NULL, MS_BIND, NULL) >= 0);
rf = path_is_mount_point(dir1, 0);
rt = path_is_mount_point(dir1, AT_SYMLINK_FOLLOW);
rlf = path_is_mount_point(dirlink1, 0);
rlt = path_is_mount_point(dirlink1, AT_SYMLINK_FOLLOW);
/* its parent is a mount point, but not /file itself */
rl1f = path_is_mount_point(dirlink1file, 0);
rl1t = path_is_mount_point(dirlink1file, AT_SYMLINK_FOLLOW);
assert_se(umount(dir1) == 0);
assert_se(rf == 1);
assert_se(rt == 1);
assert_se(rlf == 0);
assert_se(rlt == 1);
assert_se(rl1f == 0);
assert_se(rl1t == 0);
} else
printf("Skipping bind mount file test: %m\n");