remove stale pidfile if no such process found

src/charon/daemon.c

@@ -611,6 +611,48 @@ private_daemon_t *daemon_create(void)
 	return this;
 }
 
+/**
+ * Check/create PID file, return TRUE if already running 
+ */
+static bool check_pidfile()
+{
+	struct stat stb;
+	FILE *file;
+	
+	if (stat(PID_FILE, &stb) == 0)
+	{
+		file = fopen(PID_FILE, "r");
+		if (file)
+		{
+			char buf[64];
+			pid_t pid = 0;
+			
+			memset(buf, 0, sizeof(buf));
+			if (fread(buf, 1, sizeof(buf), file))
+			{
+				pid = atoi(buf);
+			}
+			fclose(file);
+			if (pid && kill(pid, 0) == 0)
+			{	/* such a process is running */
+				return TRUE;
+			}
+		}
+		DBG1(DBG_DMN, "removing pidfile '"PID_FILE"', process not running");
+		unlink(PID_FILE);
+	}
+	
+	/* create new pidfile */
+	file = fopen(PID_FILE, "w");
+	if (file)
+	{
+		fprintf(file, "%d\n", getpid());
+		ignore_result(fchown(fileno(file), charon->uid, charon->gid));
+		fclose(file);
+	}
+	return FALSE;
+}
+
 /**
  * print command line usage and exit
  */
@@ -639,10 +681,7 @@ static void usage(const char *msg)
 int main(int argc, char *argv[])
 {
 	bool use_syslog = FALSE;
-
 	private_daemon_t *private_charon;
-	FILE *pid_file;
-	struct stat stb;
 	level_t levels[DBG_MAX];
 	int group;
 	
@@ -724,20 +763,12 @@ int main(int argc, char *argv[])
 		exit(-1);
 	}
 	
-	/* check/setup PID file */
+	if (check_pidfile())
-	if (stat(PID_FILE, &stb) == 0)
 	{
 		DBG1(DBG_DMN, "charon already running (\""PID_FILE"\" exists)");
 		destroy(private_charon);
 		exit(-1);
 	}
-	pid_file = fopen(PID_FILE, "w");
-	if (pid_file)
-	{
-		fprintf(pid_file, "%d\n", getpid());
-		ignore_result(fchown(fileno(pid_file), charon->uid, charon->gid));
-		fclose(pid_file);
-	}
 	
 	/* drop the capabilities we won't need */
 	drop_capabilities(private_charon);