From: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Date: Wed, 14 Apr 2021 11:39:14 +0000 (+0200)
Subject: basic/log: assert that %m is not used when error is not set
X-Git-Tag: v249-rc1~407^2~13
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=63275a70323f2535aa943e47e827ec65a7358f0e;p=thirdparty%2Fsystemd.git

basic/log: assert that %m is not used when error is not set

This is only done in developer mode. It is a pretty rare occurence that we
make this kind of mistake. And even if it happens, the result is just a misleading
error message. So let's only do the check in non-release builds.
---

diff --git a/src/basic/log.h b/src/basic/log.h
index 4b621097d45..f7785b016b0 100644
--- a/src/basic/log.h
+++ b/src/basic/log.h
@@ -4,6 +4,7 @@
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stdlib.h>
+#include <string.h>
 #include <syslog.h>
 
 #include "macro.h"
@@ -197,7 +198,12 @@ void log_assert_failed_return(
                 _e < 0 ? _e : -EIO;                                     \
         })
 
-#define log_full(level, ...) (void) log_full_errno((level), 0, __VA_ARGS__)
+#define log_full(level, fmt, ...)                                      \
+        ({                                                             \
+                if (BUILD_MODE_DEVELOPER)                              \
+                        assert(!strstr(fmt, "%m"));                    \
+                (void) log_full_errno((level), 0, fmt, ##__VA_ARGS__); \
+        })
 
 int log_emergency_level(void);