From 1fefa40de9ff07accc7dcdde5e5f7a0a346328c3 Mon Sep 17 00:00:00 2001
From: Fredrik Tolf <fredrik@dolda2000.com>
Date: Sat, 9 Aug 2008 21:32:00 +0200
Subject: [PATCH] Better daemonization properties.

---
 src/mctap.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 46 insertions(+), 3 deletions(-)

diff --git a/src/mctap.c b/src/mctap.c
index 842a9d6..9fce9ac 100644
--- a/src/mctap.c
+++ b/src/mctap.c
@@ -12,12 +12,15 @@
 #include <sys/ioctl.h>
 #include <sys/poll.h>
 #include <syslog.h>
+#include <signal.h>
 
 #include "utils.h"
 
+static int quit = 0;
+
 static void usage(FILE *out)
 {
-    fprintf(out, "usage: mctap [-hd] [-D TAPNAME] MCASTGROUP PORT\n");
+    fprintf(out, "usage: mctap [-hdp] [-P PIDFILE] [-D TAPNAME] MCASTGROUP PORT\n");
 }
 
 static __attribute__ ((unused)) char *formataddress(struct sockaddr *arg, socklen_t arglen)
@@ -119,7 +122,7 @@ static void bridge(int sock, int tap, struct sockaddr *dst, socklen_t dstlen)
     
     fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) | O_NONBLOCK);
     fcntl(tap, F_SETFL, fcntl(tap, F_GETFL) | O_NONBLOCK);
-    while(1) {
+    while(!quit) {
 	pfds[0].fd = sock;
 	pfds[0].events = POLLIN;
 	pfds[1].fd = tap;
@@ -189,6 +192,18 @@ static int maketap(char *name)
     return(fd);
 }
 
+static void sighand(int sig)
+{
+    switch(sig) {
+    case SIGINT:
+    case SIGTERM:
+	quit = 1;
+	break;
+    case SIGHUP:
+	break;
+    }
+}
+
 int main(int argc, char **argv)
 {
     int c;
@@ -196,12 +211,15 @@ int main(int argc, char **argv)
     struct in_addr group;
     int port;
     char *tapname;
+    char *pidfile;
     int daemonize;
     struct sockaddr_in dst;
+    FILE *pidfd;
     
     tapname = "mctap";
     daemonize = 0;
-    while((c = getopt(argc, argv, "hD:d")) >= 0) {
+    pidfile = NULL;
+    while((c = getopt(argc, argv, "hD:dpP:")) >= 0) {
 	switch(c) {
 	case 'D':
 	    tapname = optarg;
@@ -209,6 +227,12 @@ int main(int argc, char **argv)
 	case 'd':
 	    daemonize = 1;
 	    break;
+	case 'p':
+	    pidfile = (void *)-1;
+	    break;
+	case 'P':
+	    pidfile = optarg;
+	    break;
 	case 'h':
 	    usage(stdout);
 	    return(0);
@@ -217,6 +241,8 @@ int main(int argc, char **argv)
 	    exit(1);
 	}
     }
+    if(pidfile == (void *)-1)
+	pidfile = sprintf2("/var/run/mctap.%s.pid", tapname);
     if(argc - optind < 2) {
 	usage(stderr);
 	exit(1);
@@ -236,13 +262,30 @@ int main(int argc, char **argv)
     }
     openlog(sprintf2("mctap-%s", tapname), LOG_PID, LOG_DAEMON);
     
+    pidfd = NULL;
+    if((pidfile != NULL) && ((pidfd = fopen(pidfile, "w")) == NULL)) {
+	fprintf(stderr, "mctap: could not create PID file %s: %s\n", pidfile, strerror(errno));
+	exit(1);
+    }
     if(daemonize)
 	daemon(0, 0);
+    if(pidfd != NULL) {
+	fprintf(pidfd, "%i\n", getpid());
+	fclose(pidfd);
+    }
+    
+    signal(SIGTERM, sighand);
+    signal(SIGINT, sighand);
+    signal(SIGHUP, sighand);
     
     memset(&dst, 0, sizeof(dst));
     dst.sin_family = AF_INET;
     dst.sin_addr = group;
     dst.sin_port = htons(port);
     bridge(sock, tap, (struct sockaddr *)&dst, sizeof(dst));
+    syslog(LOG_INFO, "exiting");
+    
+    if(pidfile != NULL)
+	unlink(pidfile);
     return(0);
 }
-- 
2.11.0