From 3c973ad92d317df736d5a8fde67baba6b102d91e Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Sun, 14 Jan 2018 21:05:37 +0000
Subject: [PATCH] Use SIGINT (instead of overloading SIGHUP) to turn on DNSSEC
 time validation.

---
 src/dnsmasq.c |   36 +++++++++++++++++++++++++-----------
 src/dnsmasq.h |    1 +
 src/helper.c  |    3 ++-
 5 files changed, 38 insertions(+), 14 deletions(-)

--- a/src/dnsmasq.c
+++ b/src/dnsmasq.c
@@ -137,7 +137,8 @@ int main (int argc, char **argv)
   sigaction(SIGTERM, &sigact, NULL);
   sigaction(SIGALRM, &sigact, NULL);
   sigaction(SIGCHLD, &sigact, NULL);
-
+  sigaction(SIGINT, &sigact, NULL);
+  
   /* ignore SIGPIPE */
   sigact.sa_handler = SIG_IGN;
   sigaction(SIGPIPE, &sigact, NULL);
@@ -815,7 +816,7 @@ int main (int argc, char **argv)
       
       daemon->dnssec_no_time_check = option_bool(OPT_DNSSEC_TIME);
       if (option_bool(OPT_DNSSEC_TIME) && !daemon->back_to_the_future)
-	my_syslog(LOG_INFO, _("DNSSEC signature timestamps not checked until first cache reload"));
+	my_syslog(LOG_INFO, _("DNSSEC signature timestamps not checked until receipt of SIGINT"));
       
       if (rc == 1)
 	my_syslog(LOG_INFO, _("DNSSEC signature timestamps not checked until system time valid"));
@@ -1142,7 +1143,7 @@ static void sig_handler(int sig)
     {
       /* ignore anything other than TERM during startup
 	 and in helper proc. (helper ignore TERM too) */
-      if (sig == SIGTERM)
+      if (sig == SIGTERM || sig == SIGINT)
 	exit(EC_MISC);
     }
   else if (pid != getpid())
@@ -1168,6 +1169,15 @@ static void sig_handler(int sig)
 	event = EVENT_DUMP;
       else if (sig == SIGUSR2)
 	event = EVENT_REOPEN;
+      else if (sig == SIGINT)
+	{
+	  /* Handle SIGINT normally in debug mode, so
+	     ctrl-c continues to operate. */
+	  if (option_bool(OPT_DEBUG))
+	    exit(EC_MISC);
+	  else
+	    event = EVENT_TIME;
+	}
       else
 	return;
 
@@ -1295,14 +1305,7 @@ static void async_event(int pipe, time_t
       {
       case EVENT_RELOAD:
 	daemon->soa_sn++; /* Bump zone serial, as it may have changed. */
-
-#ifdef HAVE_DNSSEC
-	if (daemon->dnssec_no_time_check && option_bool(OPT_DNSSEC_VALID) && option_bool(OPT_DNSSEC_TIME))
-	  {
-	    my_syslog(LOG_INFO, _("now checking DNSSEC signature timestamps"));
-	    daemon->dnssec_no_time_check = 0;
-	  } 
-#endif
+	
 	/* fall through */
 	
       case EVENT_INIT:
@@ -1411,6 +1414,17 @@ static void async_event(int pipe, time_t
 	poll_resolv(0, 1, now);
 	break;
 
+      case EVENT_TIME:
+#ifdef HAVE_DNSSEC
+	if (daemon->dnssec_no_time_check && option_bool(OPT_DNSSEC_VALID) && option_bool(OPT_DNSSEC_TIME))
+	  {
+	    my_syslog(LOG_INFO, _("now checking DNSSEC signature timestamps"));
+	    daemon->dnssec_no_time_check = 0;
+	    clear_cache_and_reload(now);
+	  }
+#endif
+	break;
+	
       case EVENT_TERM:
 	/* Knock all our children on the head. */
 	for (i = 0; i < MAX_PROCS; i++)
--- a/src/dnsmasq.h
+++ b/src/dnsmasq.h
@@ -175,6 +175,7 @@ struct event_desc {
 #define EVENT_NEWROUTE   23
 #define EVENT_TIME_ERR   24
 #define EVENT_SCRIPT_LOG 25
+#define EVENT_TIME       26
 
 /* Exit codes. */
 #define EC_GOOD        0
--- a/src/helper.c
+++ b/src/helper.c
@@ -97,13 +97,14 @@ int create_helper(int event_fd, int err_
       return pipefd[1];
     }
 
-  /* ignore SIGTERM, so that we can clean up when the main process gets hit
+  /* ignore SIGTERM and SIGINT, so that we can clean up when the main process gets hit
      and SIGALRM so that we can use sleep() */
   sigact.sa_handler = SIG_IGN;
   sigact.sa_flags = 0;
   sigemptyset(&sigact.sa_mask);
   sigaction(SIGTERM, &sigact, NULL);
   sigaction(SIGALRM, &sigact, NULL);
+  sigaction(SIGINT, &sigact, NULL);
 
   if (!option_bool(OPT_DEBUG) && uid != 0)
     {