linux-ext4 - [PATCH 10/38] lib/blkid: suppress -Wunused-result warning in blkid_flush

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230121203230.27624-11-ebiggers@kernel.org>
Date:   Sat, 21 Jan 2023 12:32:02 -0800
From:   Eric Biggers <ebiggers@...nel.org>
To:     linux-ext4@...r.kernel.org
Subject: [PATCH 10/38] lib/blkid: suppress -Wunused-result warning in blkid_flush_cache()

From: Eric Biggers <ebiggers@...gle.com>

When _FORTIFY_SOURCE is defined, glibc annotates link() with the
warn_unused_result function attribute.  With gcc, that makes
'(void) link()' cause a -Wunused-result warning, despite the explicit
cast to void.  That's annoying, since the use case in lib/blkid/save.c
is legitimate (opportunistic backup).  So let's suppress this warning.

Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 lib/blkid/save.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/blkid/save.c b/lib/blkid/save.c
index 036f07a4a..6f4499cfd 100644
--- a/lib/blkid/save.c
+++ b/lib/blkid/save.c
@@ -154,7 +154,15 @@ int blkid_flush_cache(blkid_cache cache)
 			if (backup) {
 				sprintf(backup, "%s.old", filename);
 				unlink(backup);
+#if defined(__GNUC__) && __GNUC__ >= 5
+/* explicit (void) cast is not enough with glibc and _FORTIFY_SOURCE */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-result"
+#endif
 				(void) link(filename, backup);
+#if defined(__GNUC__) && __GNUC__ >= 5
+#pragma GCC diagnostic pop
+#endif
 				free(backup);
 			}
 			if (rename(opened, filename) < 0)
-- 
2.39.0