Fix #467: TTY services stuck in restart state after non-zero exit

When a TTY exited with non-zero code (e.g., user with shell=/sbin/false),
it would enter restart state but never recover, requiring manual restart.

The throttling logic from commit f0032ab had two issues:

  1. Duplicate exit code check in service_retry() created infinite timer loop
  2. TTYs lacked default restart_tmo, causing timer to never start

Fix by removing duplicate check and ensuring TTYs get a 2-second default
restart_tmo for proper throttling.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

Author: troglobit

src/service.c

@@ -2194,15 +2194,20 @@ int service_register(int type, char *cfg, struct rlimit rlimit[], char *file)
 		/* only set forking based on pidfile if user supplied pid: option */
 		if (pid && svc->pidfile[0] == '!')
 			svc->forking = 1;
+	}
 
-		if (svc->restart_tmo == 0) {
-			if (svc_is_forking(svc))
-				svc->restart_tmo = 2000;
-			else
-				svc->restart_tmo = 1;
-		}
+	/* Set default restart_tmo for services and TTYs that can restart */
+	if (svc_is_daemon(svc) && svc->restart_tmo == 0) {
+		if (svc_is_forking(svc))
+			svc->restart_tmo = 2000;
+		else
+			svc->restart_tmo = 1;
 	}
 
+	/* TTYs need a longer default to throttle errors (e.g., missing device) */
+	if (svc_is_tty(svc) && svc->restart_tmo == 0)
+		svc->restart_tmo = 2000;
+
 	/* Set configured limits */
 	memcpy(svc->rlimit, rlimit, sizeof(svc->rlimit));
 
@@ -2631,7 +2636,6 @@ static void service_cleanup_script(svc_t *svc)
 static void service_retry(svc_t *svc)
 {
 	char *restart_cnt = (char *)&svc->restart_cnt;
-	int rc = WEXITSTATUS(svc->status);
 	int timeout;
 
 	service_timeout_cancel(svc);
@@ -2641,17 +2645,10 @@ static void service_retry(svc_t *svc)
 
 	if (svc->respawn) {
 		/*
-		 * Non-zero exit indicates an error that may not be resolved
-		 * by immediate retry. Add delay to prevent busy-loop and to
-		 * rate-limit retries, e.g. when TTY device doesn't exist.
+		 * Respawn services (TTYs) that exited with non-zero status
+		 * have already been delayed in the SVC_RUNNING_STATE handler.
+		 * Just restart now.
 		 */
-		if (WIFEXITED(svc->status) && rc != 0) {
-			dbg("%s exited with error %d, delaying respawn ...",
-			    svc_ident(svc, NULL, 0), rc);
-			service_timeout_after(svc, svc->restart_tmo, service_retry);
-			return;
-		}
-
 		dbg("%s crashed/exited, respawning ...", svc_ident(svc, NULL, 0));
 		svc_unblock(svc);
 		service_step(svc);