From ec0ee88d13987e2953b7c532c2e8e1e5506967ac Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 12 Jul 2016 13:57:23 +0300
Subject: [PATCH] Move trigger into its own subsystem

Also fixes a bug where enabling monitor without trigger would crash.
---
 main.c | 86 ++++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 59 insertions(+), 27 deletions(-)

diff --git a/main.c b/main.c
index 38624d0..00b26de 100644
--- a/main.c
+++ b/main.c
@@ -44,6 +44,16 @@ typedef struct
 	Time connection_down_time;
 } Monitor;
 
+typedef struct
+{
+	Monitor *monitor;
+	Time delay;
+	Time interval;
+	const char *command;
+	Time next;
+	pid_t child_pid;
+} Trigger;
+
 typedef struct
 {
 	const char *target_name;
@@ -62,6 +72,8 @@ Time current_time();
 int monitor_init(Monitor *);
 void monitor_check(Monitor *, Time);
 void capture_handler(uint8_t *, const struct pcap_pkthdr *, const uint8_t *);
+int trigger_init(Trigger *);
+void trigger_check(Trigger *, Time);
 int get_inet_scope(uint32_t, const Address *);
 int get_inet6_scope(const struct in6_addr *, const Address *);
 int pinger_init(Pinger *);
@@ -76,17 +88,18 @@ int verbose;
 int main(int argc, char **argv)
 {
 	Monitor monitor;
+	Trigger trigger;
 	Pinger pinger;
 	int o;
 	char *endp;
 	Time stats_interval = 1800000000ULL;
-	Time trigger_delay = 60000000ULL;
-	Time trigger_interval = 600000000ULL;
-	const char *trigger_cmd = NULL;
 
 	no_daemon = 0;
 	verbose = 0;
 	monitor.interface_name = NULL;
+	trigger.monitor = &monitor;
+	trigger.delay = 60000000ULL;
+	trigger.interval = 600000000ULL;
 	pinger.target_name = NULL;
 
 	/* Parse options */
@@ -103,14 +116,14 @@ int main(int argc, char **argv)
 			stats_interval = strtoul(optarg, NULL, 10)*1000000;
 			break;
 		case 't':
-			trigger_delay = strtoul(optarg, &endp, 10)*1000000;
+			trigger.delay = strtoul(optarg, &endp, 10)*1000000;
 			if(*endp==',')
-				trigger_interval = strtoul(endp+1, NULL, 10)*1000000;
+				trigger.interval = strtoul(endp+1, NULL, 10)*1000000;
 			else
-				trigger_interval = trigger_delay;
+				trigger.interval = trigger.delay;
 			break;
 		case 'c':
-			trigger_cmd = optarg;
+			trigger.command = optarg;
 			break;
 		case 'i':
 			monitor.interface_name = strdup(optarg);
@@ -121,8 +134,13 @@ int main(int argc, char **argv)
 		}
 
 	if(monitor.interface_name)
+	{
 		monitor_init(&monitor);
 
+		if(trigger.command)
+			trigger_init(&trigger);
+	}
+
 	if(pinger.target_name)
 		pinger_init(&pinger);
 
@@ -132,8 +150,6 @@ int main(int argc, char **argv)
 	openlog("netmon", 0, LOG_LOCAL7);
 
 	Time next_stats = current_time()+stats_interval;
-	Time next_trigger = trigger_delay;
-	pid_t child_pid = 0;
 	while(1)
 	{
 		Time time = current_time();
@@ -142,17 +158,8 @@ int main(int argc, char **argv)
 		{
 			monitor_check(&monitor, time);
 
-			if(monitor.connection_status)
-				next_trigger = trigger_delay;
-			else if(time>=monitor.last_receive+next_trigger)
-			{
-				if(no_daemon)
-					printf("Running %s\n", trigger_cmd);
-				else
-					syslog(LOG_INFO, "Running %s", trigger_cmd);
-				child_pid = run_command(trigger_cmd);
-				next_trigger += trigger_interval;
-			}
+			if(trigger.command)
+				trigger_check(&trigger, time);
 		}
 
 		if(pinger.target_name)
@@ -175,13 +182,6 @@ int main(int argc, char **argv)
 				next_stats += stats_interval;
 			}
 		}
-
-		/* Reap any finished child process */
-		if(child_pid)
-		{
-			if(waitpid(child_pid, NULL, WNOHANG)==child_pid)
-				child_pid = 0;
-		}
 	}
 
 	closelog();
@@ -322,6 +322,38 @@ void capture_handler(uint8_t *user, const struct pcap_pkthdr *header, const uint
 		monitor->last_transmit = timestamp;
 }
 
+int trigger_init(Trigger *trigger)
+{
+	trigger->next = trigger->delay;
+	trigger->child_pid = 0;
+
+	return 0;
+}
+
+void trigger_check(Trigger *trigger, Time time)
+{
+	Monitor *monitor = trigger->monitor;
+
+	if(monitor->connection_status)
+		trigger->next = trigger->delay;
+	else if(time>=monitor->last_receive+trigger->next)
+	{
+		if(no_daemon)
+			printf("Running %s\n", trigger->command);
+		else
+			syslog(LOG_INFO, "Running %s", trigger->command);
+		trigger->child_pid = run_command(trigger->command);
+		trigger->next += trigger->interval;
+	}
+
+	/* Reap any finished child process */
+	if(trigger->child_pid)
+	{
+		if(waitpid(trigger->child_pid, NULL, WNOHANG)==trigger->child_pid)
+			trigger->child_pid = 0;
+	}
+}
+
 int get_inet_scope(uint32_t addr, const Address *local_addr)
 {
 	uint32_t diff = addr^((struct sockaddr_in *)&local_addr->address)->sin_addr.s_addr;
-- 
2.43.0