Append /etc/resolv.conf.tail if it exists

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## v1.0 (2019-11-29)
+
+* Append `/etc/resolv.conf.tail` to `/etc/resolv.conf` if it exists.
+* Fixed usage.
+
 ## v0.9 (2019-06-26)
 
 * Added support for `-c` to specify the probing order of different cloud stacks.

agent/main.c

@@ -838,7 +838,7 @@ agent_network(struct system_config *sc)
 	const char	*family;
 	char		 domain[(NI_MAXHOST + 1) * 6 + 8]; /* up to 6 domains */
 	int		 has_domain = 0;
-	char		 ifidx[UINT16_MAX];
+	char		 ifidx[UINT16_MAX], *str;
 	const char	*comment = "# Generated by cloud-agent";
 
 	if (!sc->sc_network)
@@ -907,6 +907,12 @@ agent_network(struct system_config *sc)
 	if (has_domain)
 		fileout(domain, "a", "/etc/resolv.conf");
 
+	/* append resolv.conf.tail if it exists */
+	if ((str = filein("r", "/etc/resolv.conf.tail")) != NULL) {
+		fileout(str, "a", "/etc/resolv.conf");
+		free(str);
+	}
+
 	return (0);
 }