From 650c7a2e8bdd95e69bb2e4a69cf9ea43370aead5 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 30 Apr 2019 09:52:35 +0200
Subject: [PATCH 1/2] umask-util: simplify RUN_WITH_UMASK()

Why have a struct to store the iteration bit if we actually have plenty
place in mode_t?
---
 src/basic/umask-util.h | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/src/basic/umask-util.h b/src/basic/umask-util.h
index e964292eaf..cad745170e 100644
--- a/src/basic/umask-util.h
+++ b/src/basic/umask-util.h
@@ -8,21 +8,19 @@
 #include "macro.h"
 
 static inline void umaskp(mode_t *u) {
-        umask(*u);
+        umask(*u & 0777);
 }
 
 #define _cleanup_umask_ _cleanup_(umaskp)
 
-struct _umask_struct_ {
-        mode_t mask;
-        bool quit;
-};
+/* We make use of the fact here that the umask() concept is using 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 RUN_WITH_UMASK() loop, so that we can run the first
+ * one, and exit on the second. */
 
-static inline void _reset_umask_(struct _umask_struct_ *s) {
-        umask(s->mask);
-};
+assert_cc((S_IFMT & 0777) == 0);
 
 #define RUN_WITH_UMASK(mask)                                            \
-        for (_cleanup_(_reset_umask_) struct _umask_struct_ _saved_umask_ = { umask(mask), false }; \
-             !_saved_umask_.quit ;                                      \
-             _saved_umask_.quit = true)
+        for (_cleanup_umask_ mode_t _saved_umask_ = umask(mask) | S_IFMT; \
+             FLAGS_SET(_saved_umask_, S_IFMT);                          \
+             _saved_umask_ &= 0777)

From 043d453c40da0491388bcdfa2f7a1625d400e57c Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 30 Apr 2019 09:53:09 +0200
Subject: [PATCH 2/2] tests: add test for umask-util.h

---
 src/test/meson.build       |  4 ++++
 src/test/test-umask-util.c | 41 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 src/test/test-umask-util.c

diff --git a/src/test/meson.build b/src/test/meson.build
index e58e1cc73d..c68229b536 100644
--- a/src/test/meson.build
+++ b/src/test/meson.build
@@ -269,6 +269,10 @@ tests += [
          [],
          []],
 
+        [['src/test/test-umask-util.c'],
+         [],
+         []],
+
         [['src/test/test-proc-cmdline.c'],
          [],
          []],
diff --git a/src/test/test-umask-util.c b/src/test/test-umask-util.c
new file mode 100644
index 0000000000..27f6b56541
--- /dev/null
+++ b/src/test/test-umask-util.c
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "tests.h"
+#include "umask-util.h"
+
+int main(int argc, char *argv[]) {
+        size_t n;
+        mode_t u;
+
+        test_setup_logging(LOG_DEBUG);
+
+        u = umask(0111);
+
+        n = 0;
+        RUN_WITH_UMASK(0123) {
+                assert_se(umask(000) == 0123);
+                n++;
+        }
+
+        assert_se(n == 1);
+        assert_se(umask(u) == 0111);
+
+        RUN_WITH_UMASK(0135) {
+                assert_se(umask(000) == 0135);
+                n++;
+        }
+
+        assert_se(n == 2);
+        assert_se(umask(0111) == u);
+
+        RUN_WITH_UMASK(0315) {
+                assert_se(umask(000) == 0315);
+                n++;
+                break;
+        }
+
+        assert_se(n == 3);
+        assert_se(umask(u) == 0111);
+
+        return EXIT_SUCCESS;
+}