util: introduce format_ifname()

src/basic/format-util.c

@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "format-util.h"
+#include "memory-util.h"
+
+char *format_ifname(int ifindex, char buf[static IF_NAMESIZE + 1]) {
+        /* Buffer is always cleared */
+        memzero(buf, IF_NAMESIZE + 1);
+        return if_indextoname(ifindex, buf);
+}

src/basic/format-util.h

@@ -2,6 +2,7 @@
 #pragma once
 
 #include <inttypes.h>
+#include <net/if.h>
 
 #if SIZEOF_PID_T == 4
 #  define PID_PRI PRIi32
@@ -65,3 +66,5 @@
 #else
 #  error Unknown ino_t size
 #endif
+
+char *format_ifname(int ifindex, char buf[static IF_NAMESIZE + 1]);

src/basic/meson.build

@@ -56,6 +56,7 @@ basic_sources = files('''
         fd-util.h
         fileio.c
         fileio.h
+        format-util.c
         format-util.h
         fs-util.c
         fs-util.h