basic/label: introduce mkdirat_label()/mkdirat_errno_wrapper() helpers

src/basic/label.h

@@ -12,6 +12,7 @@ typedef enum LabelFixFlags {
 int label_fix(const char *path, LabelFixFlags flags);
 
 int mkdir_label(const char *path, mode_t mode);
+int mkdirat_label(int dirfd, const char *path, mode_t mode);
 int symlink_label(const char *old_path, const char *new_path);
 
 int btrfs_subvol_make_label(const char *path);

src/basic/mkdir-label.c

@@ -28,6 +28,23 @@ int mkdir_label(const char *path, mode_t mode) {
         return mac_smack_fix(path, 0);
 }
 
+int mkdirat_label(int dirfd, const char *path, mode_t mode) {
+        int r;
+
+        assert(path);
+
+        r = mac_selinux_create_file_prepare_at(dirfd, path, S_IFDIR);
+        if (r < 0)
+                return r;
+
+        r = mkdirat_errno_wrapper(dirfd, path, mode);
+        mac_selinux_create_file_clear();
+        if (r < 0)
+                return r;
+
+        return mac_smack_fix_at(dirfd, path, 0);
+}
+
 int mkdir_safe_label(const char *path, mode_t mode, uid_t uid, gid_t gid, MkdirFlags flags) {
         return mkdir_safe_internal(path, mode, uid, gid, flags, mkdir_label);
 }

src/basic/mkdir.c

@@ -80,6 +80,12 @@ int mkdir_errno_wrapper(const char *pathname, mode_t mode) {
         return 0;
 }
 
+int mkdirat_errno_wrapper(int dirfd, const char *pathname, mode_t mode) {
+        if (mkdirat(dirfd, pathname, mode) < 0)
+                return -errno;
+        return 0;
+}
+
 int mkdir_safe(const char *path, mode_t mode, uid_t uid, gid_t gid, MkdirFlags flags) {
         return mkdir_safe_internal(path, mode, uid, gid, flags, mkdir_errno_wrapper);
 }

src/basic/mkdir.h

@@ -9,6 +9,7 @@ typedef enum MkdirFlags {
 } MkdirFlags;
 
 int mkdir_errno_wrapper(const char *pathname, mode_t mode);
+int mkdirat_errno_wrapper(int dirfd, const char *pathname, mode_t mode);
 int mkdir_safe(const char *path, mode_t mode, uid_t uid, gid_t gid, MkdirFlags flags);
 int mkdir_parents(const char *path, mode_t mode);
 int mkdir_p(const char *path, mode_t mode);