dropin: add format attribute and fix a wrong caller

2 files changed, 4 insertions, 2 deletions

diff --git a/src/shared/dropin.h b/src/shared/dropin.h
index 27a2b2953f..9c9742d0e4 100644
--- a/src/shared/dropin.h
+++ b/src/shared/dropin.h
@@ -21,6 +21,8 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include "macro.h"
+
 int drop_in_file(const char *dir, const char *unit, unsigned level,
                  const char *name, char **_p, char **_q);
 
@@ -28,4 +30,4 @@ int write_drop_in(const char *dir, const char *unit, unsigned level,
                   const char *name, const char *data);
 
 int write_drop_in_format(const char *dir, const char *unit, unsigned level,
-                         const char *name, const char *format, ...);
+                         const char *name, const char *format, ...) _printf_(5, 6);
diff --git a/src/shared/generator.c b/src/shared/generator.c
index 2f9e5954c2..5d4cb5d54f 100644
--- a/src/shared/generator.c
+++ b/src/shared/generator.c
@@ -148,7 +148,7 @@ int generator_write_timeouts(const char *dir, const char *what, const char *wher
 
         return write_drop_in_format(dir, unit, 50, "device-timeout",
                                     "# Automatically generated by %s\n\n"
-                                    "[Unit]\nJobTimeoutSec=%u",
+                                    "[Unit]\nJobTimeoutSec=%lu",
                                     program_invocation_short_name,
                                     u / USEC_PER_SEC);
 }