From f2763b95afc57b88dc9d494b3fbf3841ba38a314 Mon Sep 17 00:00:00 2001
From: Daniel Golle <daniel@makrotopia.org>
Date: Wed, 7 Sep 2022 18:24:22 +0100
Subject: [PATCH] fix-build: avoid spurious extra vararg and a missing stdlib.h
 include

exim_nullstd() calls string_open_failed("/dev/null", NULL) - a
variadic, format-string-checked helper - with a literal path as the
format string and an unused NULL vararg, since the literal contains
no conversion specifier. Use a proper "%s" format with the path as
its argument instead, via a named devnullpath constant shared with
the preceding open() call.

local_scan.h is missing an explicit #include <stdlib.h>, relying on
it being pulled in transitively by another header.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 src/exim.c       | 6 ++++--
 src/local_scan.h | 1 +
 2 files changed, 5 insertions(+), 2 deletions(-)

--- a/src/exim.c
+++ b/src/exim.c
@@ -668,13 +668,15 @@ exim_nullstd(void)
 {
 int devnull = -1;
 struct stat statbuf;
+const char devnullpath[] = "/dev/null";
+
 for (int i = 0; i <= 2; i++)
   {
   if (fstat(i, &statbuf) < 0 && errno == EBADF)
     {
-    if (devnull < 0) devnull = open("/dev/null", O_RDWR);
+    if (devnull < 0) devnull = open(devnullpath, O_RDWR);
     if (devnull < 0) log_write_die(LOG_MAIN, "%s",
-      string_open_failed("/dev/null", NULL));
+      string_open_failed("%s", devnullpath));
     if (devnull != i) (void)dup2(devnull, i);
     }
   }
--- a/src/local_scan.h
+++ b/src/local_scan.h
@@ -30,6 +30,7 @@ settings, and the store functions. */
 
 #include <stdarg.h>
 #include <stdint.h>
+#include <stdlib.h>
 #include <sys/types.h>
 #pragma GCC visibility push(default)
 #include "config.h"