From 351758d85b07fc3f9aeb5cb69c7b1c9cddf1b0fa Mon Sep 17 00:00:00 2001
From: Pawel Jakub Dawidek <pjd@FreeBSD.org>
Date: Mon, 21 Mar 2011 15:29:20 +0000
Subject: [PATCH] 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
---
 sbin/hastd/hastd.c | 71 ++++++++++++++++++++++++++++------------------
 1 file changed, 43 insertions(+), 28 deletions(-)

diff --git a/sbin/hastd/hastd.c b/sbin/hastd/hastd.c
index c09c92e2239c..3f09cc76196d 100644
--- a/sbin/hastd/hastd.c
+++ b/sbin/hastd/hastd.c
@@ -884,19 +884,12 @@ connection_migrate(struct hast_resource *res)
 }
 
 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))