From: Harald Hoyer <har...@redhat.com> path_is_mount_point() compares the mount_id of a directory and the mount_id of the parent directory. When following symlinks, the function to get the parent directory does not take the symlink into account.
/bin -> /usr/bin with /usr being a mountpoint: mount_id of /bin with AT_SYMLINK_FOLLOW != mount_id of / --- V2 with openat and all relative V3 with _cleanup_close_ src/shared/path-util.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) diff --git a/src/shared/path-util.c b/src/shared/path-util.c index b9db7f1..5b7fed5 100644 --- a/src/shared/path-util.c +++ b/src/shared/path-util.c @@ -456,9 +456,9 @@ int path_is_mount_point(const char *t, bool allow_symlink) { union file_handle_union h = FILE_HANDLE_INIT; int mount_id = -1, mount_id_parent = -1; - _cleanup_free_ char *parent = NULL; struct stat a, b; int r; + _cleanup_close_ int fd = -1; bool nosupp = false; /* We are not actually interested in the file handles, but @@ -468,7 +468,15 @@ int path_is_mount_point(const char *t, bool allow_symlink) { if (path_equal(t, "/")) return 1; - r = name_to_handle_at(AT_FDCWD, t, &h.handle, &mount_id, allow_symlink ? AT_SYMLINK_FOLLOW : 0); + fd = openat(AT_FDCWD, t, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|(allow_symlink ? 0 : O_PATH)); + if (fd < 0) { + if (errno == ENOENT) + return 0; + + return -errno; + } + + r = name_to_handle_at(fd, "", &h.handle, &mount_id, AT_EMPTY_PATH); if (r < 0) { if (errno == ENOSYS) /* This kernel does not support name_to_handle_at() @@ -485,12 +493,9 @@ int path_is_mount_point(const char *t, bool allow_symlink) { return -errno; } - r = path_get_parent(t, &parent); - if (r < 0) - return r; h.handle.handle_bytes = MAX_HANDLE_SZ; - r = name_to_handle_at(AT_FDCWD, parent, &h.handle, &mount_id_parent, AT_SYMLINK_FOLLOW); + r = name_to_handle_at(fd, "..", &h.handle, &mount_id_parent, 0); if (r < 0) if (errno == EOPNOTSUPP) if (nosupp) @@ -509,10 +514,7 @@ int path_is_mount_point(const char *t, bool allow_symlink) { return mount_id != mount_id_parent; fallback: - if (allow_symlink) - r = stat(t, &a); - else - r = lstat(t, &a); + r = fstatat(fd, "", &a, AT_EMPTY_PATH); if (r < 0) { if (errno == ENOENT) @@ -521,14 +523,8 @@ fallback: return -errno; } - free(parent); - parent = NULL; - - r = path_get_parent(t, &parent); - if (r < 0) - return r; - r = stat(parent, &b); + r = fstatat(fd, "..", &b, 0); if (r < 0) return -errno; -- 2.3.0 _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel