diff options
| -rw-r--r-- | src/shared/path-util.c | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/src/shared/path-util.c b/src/shared/path-util.c index 8678ef516b..6855937a10 100644 --- a/src/shared/path-util.c +++ b/src/shared/path-util.c @@ -331,12 +331,14 @@ bool path_equal(const char *a, const char *b) { } int fd_is_mount_point(int fd) { - union file_handle_union h = FILE_HANDLE_INIT; + union file_handle_union h = FILE_HANDLE_INIT, h_parent = FILE_HANDLE_INIT; int mount_id = -1, mount_id_parent = -1; bool nosupp = false; struct stat a, b; int r; + assert(fd >= 0); + /* We are not actually interested in the file handles, but * name_to_handle_at() also passes us the mount ID, hence use * it but throw the handle away */ @@ -360,8 +362,7 @@ int fd_is_mount_point(int fd) { return -errno; } - h.handle.handle_bytes = MAX_HANDLE_SZ; - r = name_to_handle_at(fd, "..", &h.handle, &mount_id_parent, 0); + r = name_to_handle_at(fd, "..", &h_parent.handle, &mount_id_parent, 0); if (r < 0) { if (errno == EOPNOTSUPP) { if (nosupp) @@ -380,8 +381,19 @@ int fd_is_mount_point(int fd) { * directory we are interested in can't? If so, it * must be a mount point. */ return 1; - else + else { + /* If the file handle for the directory we are + * interested in and its parent are identical, we + * assume this is the root directory, which is a mount + * point. */ + + if (h.handle.handle_bytes == h_parent.handle.handle_bytes && + h.handle.handle_type == h_parent.handle.handle_type && + memcmp(h.handle.f_handle, h_parent.handle.f_handle, h.handle.handle_bytes) == 0) + return 1; + return mount_id != mount_id_parent; + } fallback: r = fstatat(fd, "", &a, AT_EMPTY_PATH); @@ -396,6 +408,12 @@ fallback: if (r < 0) return -errno; + /* A directory with same device and inode as its parent? Must + * be the root directory */ + if (a.st_dev == b.st_dev && + a.st_ino == b.st_ino) + return 1; + return a.st_dev != b.st_dev; } |