[src/trunk]: src/usr.sbin/ypbind Add a SIGHUP handler; upon SIGHUP do an extr...

[dholland <dholland%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/06b4cdc7fa53
branches:  trunk
changeset: 329814:06b4cdc7fa53
user:      dholland <dholland%NetBSD.org@localhost>
date:      Tue Jun 10 17:19:36 2014 +0000

description:
Add a SIGHUP handler; upon SIGHUP do an extra nag_servers on any
domain that's in DEAD state. This lets you explicitly rescue ypbind
from its exponential backoff when you know the world's back up.

diffstat:

 usr.sbin/ypbind/ypbind.c |  71 +++++++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 67 insertions(+), 4 deletions(-)

diffs (129 lines):

diff -r 796b3e4dd37f -r 06b4cdc7fa53 usr.sbin/ypbind/ypbind.c
--- a/usr.sbin/ypbind/ypbind.c  Tue Jun 10 17:19:22 2014 +0000
+++ b/usr.sbin/ypbind/ypbind.c  Tue Jun 10 17:19:36 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ypbind.c,v 1.96 2014/06/10 17:19:22 dholland Exp $     */
+/*     $NetBSD: ypbind.c,v 1.97 2014/06/10 17:19:36 dholland Exp $     */
 
 /*
  * Copyright (c) 1992, 1993 Theo de Raadt <deraadt%fsa.ca@localhost>
@@ -28,7 +28,7 @@
 
 #include <sys/cdefs.h>
 #ifndef LINT
-__RCSID("$NetBSD: ypbind.c,v 1.96 2014/06/10 17:19:22 dholland Exp $");
+__RCSID("$NetBSD: ypbind.c,v 1.97 2014/06/10 17:19:36 dholland Exp $");
 #endif
 
 #include <sys/types.h>
@@ -50,6 +50,7 @@
 #include <ifaddrs.h>
 #include <limits.h>
 #include <netdb.h>
+#include <signal.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -133,6 +134,9 @@
 /* The ypbind service transports */
 static SVCXPRT *udptransp, *tcptransp;
 
+/* set if we get SIGHUP */
+static sig_atomic_t hupped;
+
 ////////////////////////////////////////////////////////////
 // utilities
 
@@ -1533,6 +1537,51 @@
        }
 }
 
+/*
+ * Process a hangup signal.
+ *
+ * Do an extra nag_servers() for any domains that are DEAD. This way
+ * if you know things are back up you can restore service by sending
+ * ypbind a SIGHUP rather than waiting for the timeout period.
+ */
+static void
+dohup(void)
+{
+       struct domain *dom;
+
+       hupped = 0;
+       for (dom = domains; dom != NULL; dom = dom->dom_next) {
+               if (dom->dom_state == DOM_DEAD) {
+                       (void)nag_servers(dom);
+               }
+       }
+}
+
+/*
+ * Receive a hangup signal.
+ */
+static void
+hup(int __unused sig)
+{
+       hupped = 1;
+}
+
+/*
+ * Initialize hangup processing.
+ */
+static void
+starthup(void)
+{
+       struct sigaction sa;
+
+       sa.sa_handler = hup;
+       sigemptyset(&sa.sa_mask);
+       sa.sa_flags = SA_RESTART;
+       if (sigaction(SIGHUP, &sa, NULL) == -1) {
+               err(1, "sigaction");
+       }
+}
+
 ////////////////////////////////////////////////////////////
 // main
 
@@ -1615,6 +1664,9 @@
        if (lockfd == -1)
                err(1, "Cannot create %s", _PATH_YPBIND_LOCK);
 
+       /* Accept hangups. */
+       starthup();
+
        /* Initialize sunrpc stuff. */
        sunrpc_setup();
 
@@ -1672,12 +1724,24 @@
                switch (select(width, &fdsr, NULL, NULL, &tv)) {
                case 0:
                        /* select timed out - check for timer-based work */
+                       if (hupped) {
+                               dohup();
+                       }
                        checkwork();
                        break;
                case -1:
-                       yp_log(LOG_WARNING, "select: %s", strerror(errno));
+                       if (hupped) {
+                               dohup();
+                       }
+                       if (errno != EINTR) {
+                               yp_log(LOG_WARNING, "select: %s",
+                                      strerror(errno));
+                       }
                        break;
                default:
+                       if (hupped) {
+                               dohup();
+                       }
                        /* incoming of our own; read it */
                        if (FD_ISSET(rpcsock, &fdsr))
                                (void)handle_replies();
@@ -1716,4 +1780,3 @@
                }
        }
 }
-