From: Serge Hallyn <serge@hallyn.com>
Date: Thu, 14 Dec 2017 21:56:24 +0000 (-0600)
Subject: Merge pull request #2039 from brauner/2017-12-14/fix_command_socket_race
X-Git-Tag: lxc-3.0.0.beta1~107
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=389c46753ba4a8bf446575cc6e2ab508309bd9b2;p=thirdparty%2Flxc.git

Merge pull request #2039 from brauner/2017-12-14/fix_command_socket_race

commands: fix race when open()/close() cmd socket
---

389c46753ba4a8bf446575cc6e2ab508309bd9b2
diff --cc src/lxc/start.c
index 5052e2d5a,4911fdde3..e17507606
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@@ -784,15 -753,25 +784,25 @@@ void lxc_fini(const char *name, struct 
  
  	cgroup_destroy(handler);
  
- 	lxc_set_state(name, handler, STOPPED);
+ 	/* This function will try to connect to the legacy lxc-monitord state
+ 	 * server and only exists for backwards compatibility.
+ 	 */
+ 	lxc_monitor_send_state(name, STOPPED, handler->lxcpath);
  
  	if (handler->conf->reboot == 0) {
- 		/* close command socket */
+ 		/* For all new state clients simply close the command socket.
+ 		 * This will inform all state clients that the container is
+ 		 * STOPPED and also prevents a race between a open()/close() on
+ 		 * the command socket causing a new process to get ECONNREFUSED
+ 		 * because we haven't yet closed the command socket.
+ 		 */
  		close(handler->conf->maincmd_fd);
  		handler->conf->maincmd_fd = -1;
+ 	} else {
+ 		lxc_set_state(name, handler, STOPPED);
  	}
  
 -	if (run_lxc_hooks(name, "post-stop", handler->conf, handler->lxcpath, NULL)) {
 +	if (run_lxc_hooks(name, "post-stop", handler->conf, NULL)) {
  		ERROR("Failed to run lxc.hook.post-stop for container \"%s\".", name);
  		if (handler->conf->reboot) {
  			WARN("Container will be stopped instead of rebooted.");