From 03cf00cbf31a8e8168757269982e8e0296a3549f Mon Sep 17 00:00:00 2001
From: Oleksij Rempel <linux@rempel-privat.de>
Date: Thu, 1 Jan 2026 18:24:52 +0100
Subject: [PATCH] canlogserver: fix infinite loops during signal handling

Previously, the `canlogserver` could get stuck in infinite loops when
receiving a signal (e.g., SIGINT via Ctrl-C) in two scenarios:

1. Inside the `bind()` retry loop: If the port was busy (e.g., in
   TIME_WAIT), the loop retried indefinitely using `nanosleep` without
   checking the `running` flag set by the signal handler.

2. Inside the `accept()` loop: The loop was unconditional (`while(1)`).
   If `accept()` was interrupted by a signal, it returned with `EINTR`,
   but the loop immediately restarted, effectively ignoring the shutdown
   request.

This patch adds checks for the `running` flag in both loops to ensure
the server terminates correctly upon receiving a signal. It also ensures
the socket is closed properly and the correct exit code (128 + signal
number) is returned.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
---
 canlogserver.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/canlogserver.c b/canlogserver.c
index 3e9c44f..abc62b4 100644
--- a/canlogserver.c
+++ b/canlogserver.c
@@ -177,7 +177,8 @@ int main(int argc, char **argv)
 	sigset_t sigset;
 	fd_set rdfs;
 	int s[MAXDEV];
-	int socki, accsocket;
+	int socki;
+	int accsocket = -1;
 	canid_t mask[MAXDEV] = {0};
 	canid_t value[MAXDEV] = {0};
 	int inv_filter[MAXDEV] = {0};
@@ -286,7 +287,7 @@ int main(int argc, char **argv)
 	inaddr.sin_addr.s_addr = htonl(INADDR_ANY);
 	inaddr.sin_port = htons(port);
 
-	while(bind(socki, (struct sockaddr*)&inaddr, sizeof(inaddr)) < 0) {
+	while(running && bind(socki, (struct sockaddr*)&inaddr, sizeof(inaddr)) < 0) {
 		struct timespec f = {
 			.tv_nsec = 100 * 1000 * 1000,
 		};
@@ -295,12 +296,17 @@ int main(int argc, char **argv)
 		nanosleep(&f, NULL);
 	}
 
+	if (!running) {
+		close(socki);
+		return 128 + signal_num;
+	}
+
 	if (listen(socki, 3) != 0) {
 		perror("listen");
 		exit(1);
 	}
 
-	while(1) {
+	while(running) {
 		accsocket = accept(socki, (struct sockaddr*)&clientaddr, &sin_size);
 		if (accsocket > 0) {
 			//printf("accepted\n");
@@ -314,6 +320,11 @@ int main(int argc, char **argv)
 		}
 	}
 
+	if (!running) {
+		close(socki);
+		return 128 + signal_num;
+	}
+
 	for (i=0; i<currmax; i++) {
 
 		pr_debug("open %d '%s' m%08X v%08X i%d e%d.\n",