diff options
| -rw-r--r-- | src/shared/path-util.c | 16 | ||||
| -rw-r--r-- | src/test/test-path-util.c | 81 |
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"); 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