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-rw-r--r--src/shared/path-util.c16
-rw-r--r--src/test/test-path-util.c81
2 files changed, 92 insertions, 5 deletions
diff --git a/src/shared/path-util.c b/src/shared/path-util.c
index be50a1865d..537705446a 100644
--- a/src/shared/path-util.c
+++ b/src/shared/path-util.c
@@ -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) {
diff --git a/src/test/test-path-util.c b/src/test/test-path-util.c
index 0045ae6824..fce4e81a09 100644
--- a/src/test/test-path-util.c
+++ b/src/test/test-path-util.c
@@ -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");