Before handling any events on descriptors check signals so we can update

our info about worker processes if any of them was terminated in the meantime.

This fixes the problem with 'hastctl status' running from a hook called on
split-brain:
1. Secondary calls a hooks and terminates.
2. Hook asks for resource status via 'hastctl status'.
3. The main hastd handles the status request by sending it to the secondary
   worker who is already dead, but because signals weren't checked yet he
   doesn't know that and we get EPIPE.

MFC after:	1 week

1 files changed, 43 insertions, 28 deletions

diff --git a/sbin/hastd/hastd.c b/sbin/hastd/hastd.c
index c09c92e..3f09cc7 100644
--- a/sbin/hastd/hastd.c
+++ b/sbin/hastd/hastd.c
@@ -884,19 +884,12 @@ out:
 }
 
 static void
-main_loop(void)
+check_signals(void)
 {
-	struct hast_resource *res;
-	struct timeval seltimeout;
 	struct timespec sigtimeout;
-	int fd, maxfd, ret, signo;
-	time_t lastcheck, now;
 	sigset_t mask;
-	fd_set rfds;
+	int signo;
 
-	lastcheck = time(NULL);	
-	seltimeout.tv_sec = REPORT_INTERVAL;
-	seltimeout.tv_usec = 0;
 	sigtimeout.tv_sec = 0;
 	sigtimeout.tv_nsec = 0;
 
@@ -906,29 +899,45 @@ main_loop(void)
 	PJDLOG_VERIFY(sigaddset(&mask, SIGTERM) == 0);
 	PJDLOG_VERIFY(sigaddset(&mask, SIGCHLD) == 0);
 
+	while ((signo = sigtimedwait(&mask, NULL, &sigtimeout)) != -1) {
+		switch (signo) {
+		case SIGINT:
+		case SIGTERM:
+			sigexit_received = true;
+			terminate_workers();
+			proto_close(cfg->hc_controlconn);
+			exit(EX_OK);
+			break;
+		case SIGCHLD:
+			child_exit();
+			break;
+		case SIGHUP:
+			hastd_reload();
+			break;
+		default:
+			PJDLOG_ABORT("Unexpected signal (%d).", signo);
+		}
+	}
+}
+
+static void
+main_loop(void)
+{
+	struct hast_resource *res;
+	struct timeval seltimeout;
+	int fd, maxfd, ret;
+	time_t lastcheck, now;
+	fd_set rfds;
+
+	lastcheck = time(NULL);	
+	seltimeout.tv_sec = REPORT_INTERVAL;
+	seltimeout.tv_usec = 0;
+
 	pjdlog_info("Started successfully, running protocol version %d.",
 	    HAST_PROTO_VERSION);
 
 	for (;;) {
-		while ((signo = sigtimedwait(&mask, NULL, &sigtimeout)) != -1) {
-			switch (signo) {
-			case SIGINT:
-			case SIGTERM:
-				sigexit_received = true;
-				terminate_workers();
-				proto_close(cfg->hc_controlconn);
-				exit(EX_OK);
-				break;
-			case SIGCHLD:
-				child_exit();
-				break;
-			case SIGHUP:
-				hastd_reload();
-				break;
-			default:
-				PJDLOG_ABORT("Unexpected signal (%d).", signo);
-			}
-		}
+		check_signals();
 
 		/* Setup descriptors for select(2). */
 		FD_ZERO(&rfds);
@@ -976,6 +985,12 @@ main_loop(void)
 			pjdlog_exit(EX_OSERR, "select() failed");
 		}
 
+		/*
+		 * Check for signals before we do anything to update our
+		 * info about terminated workers in the meantime.
+		 */
+		check_signals();
+
 		if (FD_ISSET(proto_descriptor(cfg->hc_controlconn), &rfds))
 			control_handle(cfg);
 		if (FD_ISSET(proto_descriptor(cfg->hc_listenconn), &rfds))