Support accepting listening sockets from systemd.

src/cfg_file.h

@@ -227,6 +227,7 @@ struct rspamd_worker_bind_conf {
 	gchar *bind_host;
 	guint16 bind_port;
 	gint ai;
+	gboolean is_systemd;
 	struct rspamd_worker_bind_conf *next;
 };
 

src/cfg_utils.c

@@ -196,7 +196,7 @@ gboolean
 parse_bind_line (struct config_file *cfg, struct worker_conf *cf, const gchar *str)
 {
 	struct rspamd_worker_bind_conf *cnf;
-	gchar **tokens, *tmp;
+	gchar **tokens, *tmp, *err;
 	gboolean ret;
 
 	if (str == NULL) {
@@ -238,6 +238,14 @@ parse_bind_line (struct config_file *cfg, struct worker_conf *cf, const gchar *s
 		}
 		tokens[0] = tmp;
 	}
+	else if (strcmp (tokens[0], "systemd") == 0) {
+		/* The actual socket will be passed by systemd environment */
+		cnf->bind_host = memory_pool_strdup (cfg->cfg_pool, str);
+		cnf->ai = strtoul (tokens[1], &err, 10);
+		if (err == NULL || *err == '\0') {
+			LL_PREPEND (cf->bind_conf, cnf);
+		}
+	}
 	else {
 		if ((ret = parse_host_port_priority_strv (cfg->cfg_pool, tokens,
 				&cnf->bind_host, &cnf->bind_port, NULL, DEFAULT_BIND_PORT))) {

src/main.c

@@ -549,6 +549,48 @@ create_listen_socket (const gchar *addr, gint port, gint listen_type)
 	return result;
 }
 
+static GList *
+systemd_get_socket (gint number, gint listen_type)
+{
+	int sock, max;
+	GList *result = NULL;
+	const gchar *e;
+	gchar *err;
+	struct stat st;
+	/* XXX: can we trust the current choice ? */
+	static const int sd_listen_fds_start = 3;
+
+	e = getenv ("LISTEN_FDS");
+	if (e != NULL) {
+		errno = 0;
+		max = strtoul (e, &err, 10);
+		if ((e == NULL || *e == '\0') && max > number + sd_listen_fds_start) {
+			sock = number + sd_listen_fds_start;
+			if (fstat (sock, &st) == -1) {
+				return NULL;
+			}
+			if (!S_ISSOCK (st.st_mode)) {
+				errno = EINVAL;
+				return NULL;
+			}
+			if (listen_type != SOCK_DGRAM) {
+				if (listen (sock, -1) == -1) {
+					return NULL;
+				}
+			}
+			result = g_list_prepend (result, GINT_TO_POINTER (sock));
+		}
+		else if (max <= number + sd_listen_fds_start) {
+			errno = EOVERFLOW;
+		}
+	}
+	else {
+		errno = ENOENT;
+	}
+
+	return result;
+}
+
 static void
 fork_delayed (struct rspamd_main *rspamd)
 {
@@ -599,10 +641,16 @@ spawn_workers (struct rspamd_main *rspamd)
 				LL_FOREACH (cf->bind_conf, bcf) {
 					key = make_listen_key (bcf->ai, bcf->bind_host, bcf->bind_port);
 					if ((p = g_hash_table_lookup (listen_sockets, GINT_TO_POINTER (key))) == NULL) {
-						/* Create listen socket */
-						ls = create_listen_socket (bcf->bind_host, bcf->bind_port,
-								cf->worker->listen_type);
+						if (!bcf->is_systemd) {
+							/* Create listen socket */
+							ls = create_listen_socket (bcf->bind_host, bcf->bind_port,
+									cf->worker->listen_type);
+						}
+						else {
+							ls = systemd_get_socket (bcf->ai, cf->worker->listen_type);
+						}
 						if (ls == NULL) {
+							msg_err ("cannot listen on socket %s: %s", bcf->bind_host, strerror (errno));
 							exit (-errno);
 						}
 						g_hash_table_insert (listen_sockets, GINT_TO_POINTER (key), ls);