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Date:      Mon, 21 Mar 2011 15:29:21 +0000 (UTC)
From:      Pawel Jakub Dawidek <pjd@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r219837 - head/sbin/hastd
Message-ID:  <201103211529.p2LFTL04010139@svn.freebsd.org>
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Author: pjd
Date: Mon Mar 21 15:29:20 2011
New Revision: 219837
URL: http://svn.freebsd.org/changeset/base/219837

Log:
  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

Modified:
  head/sbin/hastd/hastd.c

Modified: head/sbin/hastd/hastd.c
==============================================================================
--- head/sbin/hastd/hastd.c	Mon Mar 21 15:23:10 2011	(r219836)
+++ head/sbin/hastd/hastd.c	Mon Mar 21 15:29:20 2011	(r219837)
@@ -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))

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