1 files changed, 29 insertions, 0 deletions
diff --git a/src/basic/umask-util.h b/src/basic/umask-util.h
new file mode 100644
index 0000000..00417fa
--- /dev/null
+++ b/src/basic/umask-util.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "macro.h"
+
+static inline void umaskp(mode_t *u) {
+        umask(*u);
+}
+
+#define _cleanup_umask_ _cleanup_(umaskp)
+
+/* We make use of the fact here that the umask() syscall uses only the lower 9 bits of mode_t, although
+ * mode_t has space for the file type in the bits further up. We simply OR in the file type mask S_IFMT to
+ * distinguish the first and the second iteration of the WITH_UMASK() loop, so that we can run the first one,
+ * and exit on the second. */
+
+assert_cc((S_IFMT & 0777) == 0);
+
+#define WITH_UMASK(mask)                                            \
+        for (_cleanup_umask_ mode_t _saved_umask_ = umask(mask) | S_IFMT; \
+             FLAGS_SET(_saved_umask_, S_IFMT);                          \
+             _saved_umask_ &= 0777)
+
+#define BLOCK_WITH_UMASK(mask) \
+        _unused_ _cleanup_umask_ mode_t _saved_umask_ = umask(mask);