utils-std

commit: 08147ec21ddca45950d806e72ebfba30f44dc3c3
parent bc2f5cfd41483c1a280c4c8cc36a2d90268db0de
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Sat, 13 Dec 2025 15:56:05 +0100

cmd/timeout: Fix SIGCHLD handler not exiting with timeout return code

Race-condition found via testing on OpenBSD

Diffstat:
M
cmd/timeout.c
16
+++++++++++-----

1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/cmd/timeout.c b/cmd/timeout.c
@@ -35,16 +35,21 @@ extern char **environ;
 
 pid_t child = 0;
 const char *argv0 = "timeout";
+static bool timeout = false;
+static int cmd_exit_timeout = CMD_EXIT_TIMEOUT;
 
 static void
 handle_sigchld(int sig)
 {
+	// Doesn't uses exit() to avoid running the atexit handlers
+	// one of which being gcc --coverage handler which causes a hang
 	(void)sig;
 	int stat_loc = 0;
+
+	if(timeout && cmd_exit_timeout != 0) _Exit(CMD_EXIT_TIMEOUT);
+
 	waitpid(child, &stat_loc, WNOHANG);
 
-	// Not exit() to avoid running the atexit handlers
-	// one of which being gcc --coverage handler which causes a hang
 	_Exit(WEXITSTATUS(stat_loc));
 }
 
@@ -62,7 +67,6 @@ main(int argc, char *argv[])
 	int term_sig = SIGTERM;
 	const char *term_signame = "SIGTERM";
 	bool kill_child = true;
-	int cmd_exit_timeout = CMD_EXIT_TIMEOUT;
 
 	char *arg = NULL;
 
@@ -184,8 +188,8 @@ main(int argc, char *argv[])
 	argc--;
 
 	struct sigaction sa = {
-		.sa_handler = handle_sigchld,
-		.sa_flags = 0,
+	    .sa_handler = handle_sigchld,
+	    .sa_flags = 0,
 	};
 	if(sigaction(SIGCHLD, &sa, NULL) != 0)
 	{
@@ -222,6 +226,8 @@ main(int argc, char *argv[])
 		}
 	}
 
+	timeout = true;
+
 	if(!kill_child)
 	{
 		return cmd_exit_timeout;