Fix up a couple more signal handlers to not do bad things that could cause

various undesirable results.  The other day, I made Asterisk deadlock by
hitting Control-C because of a bad signal handler.  Now, signal handlers
just set a flag and write to an alert pipe for the flag to be handled.  Then,
there is another thread that is monitoring for these flags.  If being run in
console mode, it is just the main thread.  If Asterisk is in the background,
a thread is created to do it.


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.2@56504 65c4cc65-6c06-0410-ace0-fbb531ad65f3

asterisk.c

@@ -234,7 +234,11 @@ static int shuttingdown = 0;
 static int restartnow = 0;
 static pthread_t consolethread = AST_PTHREADT_NULL;
 
-static unsigned int need_reload;
+static int sig_alert_pipe[2] = { -1, -1 };
+static struct {
+	 unsigned int need_reload:1;
+	 unsigned int need_quit:1;
+} sig_flags;
 
 #if !defined(LOW_MEMORY)
 struct file_version {
@@ -745,11 +749,14 @@ static void urg_handler(int num)
 
 static void hup_handler(int num)
 {
+	int a = 0;
 	if (option_verbose > 1) 
 		printf("Received HUP signal -- Reloading configs\n");
 	if (restartnow)
 		execvp(_argv[0], _argv);
-	need_reload = 1;
+	sig_flags.need_reload = 1;
+	if (sig_alert_pipe[1] != -1)
+		write(sig_alert_pipe[1], &a, sizeof(a));
 	signal(num, hup_handler);
 }
 
@@ -942,7 +949,12 @@ static void quit_handler(int num, int nice, int safeshutdown, int restart)
 
 static void __quit_handler(int num)
 {
-	quit_handler(num, 0, 1, 0);
+	int a = 0;
+	sig_flags.need_quit = 1;
+	if (sig_alert_pipe[1] != -1)
+		write(sig_alert_pipe[1], &a, sizeof(a));
+	/* There is no need to restore the signal handler here, since the app
+	 * is going to exit */
 }
 
 static const char *fix_header(char *outbuf, int maxout, const char *s, char *cmp)
@@ -1817,11 +1829,6 @@ static void ast_remotecontrol(char * data)
 				}
 			}
 		}
-
-		if (need_reload) {
-			need_reload = 0;
-			ast_module_reload(NULL);
-		}
 	}
 	printf("\nDisconnected from Asterisk server\n");
 }
@@ -2005,6 +2012,26 @@ static void ast_readconfig(void) {
 	ast_config_destroy(cfg);
 }
 
+static void *monitor_sig_flags(void *unused)
+{
+	for (;;) {
+		struct pollfd p = { sig_alert_pipe[0], POLLIN, 0 };
+		int a;
+		poll(&p, 1, -1);
+		if (sig_flags.need_reload) {
+			sig_flags.need_reload = 0;
+			ast_module_reload(NULL);
+		}
+		if (sig_flags.need_quit) {
+			sig_flags.need_quit = 0;
+			quit_handler(0, 0, 1, 0);
+		}
+		read(sig_alert_pipe[0], &a, sizeof(a));
+	}
+
+	return NULL;
+}
+
 int main(int argc, char *argv[])
 {
 	int c;
@@ -2403,6 +2430,10 @@ int main(int argc, char *argv[])
 		ast_verbose(term_color(tmp, "Asterisk Ready.\n", COLOR_BRWHITE, COLOR_BLACK, sizeof(tmp)));
 	if (option_nofork)
 		consolethread = pthread_self();
+
+	if (pipe(sig_alert_pipe))
+		sig_alert_pipe[0] = sig_alert_pipe[1] = -1;
+
 	fully_booted = 1;
 	pthread_sigmask(SIG_UNBLOCK, &sigs, NULL);
 #ifdef __AST_DEBUG_MALLOC
@@ -2414,6 +2445,14 @@ int main(int argc, char *argv[])
 		/* Console stuff now... */
 		/* Register our quit function */
 		char title[256];
+		pthread_attr_t attr;
+		pthread_t dont_care;
+
+		pthread_attr_init(&attr);
+		pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+		ast_pthread_create(&dont_care, &attr, monitor_sig_flags, NULL);
+		pthread_attr_destroy(&attr);
+
 		set_icon("Asterisk");
 		snprintf(title, sizeof(title), "Asterisk Console on '%s' (pid %d)", hostname, ast_mainpid);
 		set_title(title);
@@ -2439,21 +2478,10 @@ int main(int argc, char *argv[])
 					break;
 				}
 			}
-			if (need_reload) {
-				need_reload = 0;
-				ast_module_reload(NULL);
-			}
-		}
-	}
-	/* Do nothing */
-	for(;;)  {	/* apparently needed for the MACos */
-		struct pollfd p = { -1 /* no descriptor */, 0, 0 };
-		poll(&p, 0, -1);
-		/* SIGHUP will cause this to break out of poll() */
-		if (need_reload) {
-			need_reload = 0;
-			ast_module_reload(NULL);
 		}
 	}
+
+	monitor_sig_flags(NULL);
+
 	return 0;
 }