From: Roy Marples <roy@marples.name>
Date: Sun, 27 Jan 2008 18:39:31 +0000 (+0000)
Subject: Use sigaction over signal and check iface and state before freeing
X-Git-Tag: v3.2.3~60
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0376353cfc371c545c97716c09891ccd5e55c94c;p=thirdparty%2Fdhcpcd.git

Use sigaction over signal and check iface and state before freeing
---

diff --git a/client.c b/client.c
index c87da559..f447d9a1 100644
--- a/client.c
+++ b/client.c
@@ -1001,7 +1001,8 @@ int dhcp_run (const options_t *options, int *pidfd)
 	if (! client_setup (state, options))
 		goto eexit;
 
-	signal_setup ();
+	if (signal_setup () == -1)
+		goto eexit;
 
 	for (;;) {
 		retval = wait_for_packet (&rset, state, options);
@@ -1032,24 +1033,25 @@ int dhcp_run (const options_t *options, int *pidfd)
 	}
 
 eexit:
-	do_socket (state, SOCKET_CLOSED);
-	drop_config (state, options);
-
 	if (iface) {
+		do_socket (state, SOCKET_CLOSED);
+		drop_config (state, options);
 		free_route (iface->previous_routes);
 		free (iface);
 	}
 
-	if (state->forked)
-		retval = 0;
+	if (state) {
+		if (state->forked)
+			retval = 0;
 
-	if (state->daemonised)
-		unlink (options->pidfile);
+		if (state->daemonised)
+			unlink (options->pidfile);
 
-	free_dhcp (state->dhcp);
-	free (state->dhcp);
-	free (state->buffer);
-	free (state);
+		free_dhcp (state->dhcp);
+		free (state->dhcp);
+		free (state->buffer);
+		free (state);
+	}
 
 	return (retval);
 }
diff --git a/interface.c b/interface.c
index 8d222205..3cb4952c 100644
--- a/interface.c
+++ b/interface.c
@@ -399,7 +399,7 @@ interface_t *read_interface (const char *ifname, _unused int metric)
 
 	if (! (ifr.ifr_flags & IFF_UP) || ! (ifr.ifr_flags & IFF_RUNNING)) {
 		ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
-		if (ioctl (s, SIOCSIFFLAGS, &ifr) == -1) {
+		if (ioctl (s, SIOCSIFFLAGS, &ifr) != 0) {
 			logger (LOG_ERR, "ioctl SIOCSIFFLAGS: %s",
 				strerror (errno));
 			goto exit;
diff --git a/signal.c b/signal.c
index a1f8bff4..11e0865e 100644
--- a/signal.c
+++ b/signal.c
@@ -40,9 +40,17 @@
 static int signal_pipe[2];
 static int signals[5];
 
+static const int handle_sigs[] = {
+	SIGHUP,
+	SIGALRM,
+	SIGTERM,
+	SIGINT
+};
+
 static void signal_handler (int sig)
 {
 	unsigned int i = 0;
+	int serrno = errno;
 
 	/* Add a signal to our stack */
 	while (signals[i])
@@ -52,8 +60,11 @@ static void signal_handler (int sig)
 	else
 		signals[i] = sig;
 
-	if (send (signal_pipe[1], &sig, sizeof (sig), MSG_DONTWAIT) == -1)
+	if (write (signal_pipe[1], &sig, sizeof (sig)) == -1)
 		logger (LOG_ERR, "Could not send signal: %s", strerror (errno));
+
+	/* Restore errno */
+	errno = serrno;
 }
 
 /* Add the signal pipe to an fd set */
@@ -114,12 +125,16 @@ int signal_read (fd_set *rset)
 
 /* Call this before doing anything else. Sets up the socket pair
  * and installs the signal handler */
-void signal_setup (void)
+int signal_setup (void)
 {
 	unsigned int i;
 	int flags;
+	struct sigaction sa;
 
-	socketpair (AF_UNIX, SOCK_STREAM, 0, signal_pipe);
+	if (pipe (signal_pipe) == -1) {
+		logger (LOG_ERR, "pipe: %s", strerror (errno));
+		return (-1);
+	}
 
 	/* Stop any scripts from inheriting us */
 	for (i = 0; i < 2; i++)
@@ -127,13 +142,23 @@ void signal_setup (void)
 		    fcntl (signal_pipe[i], F_SETFD, flags | FD_CLOEXEC) == -1)
 			logger (LOG_ERR ,"fcntl: %s", strerror (errno));
 
-	signal (SIGHUP, signal_handler);
-	signal (SIGALRM, signal_handler);
-	signal (SIGTERM, signal_handler);
-	signal (SIGINT, signal_handler);
+	sa.sa_handler = signal_handler;
+	sigemptyset (&sa.sa_mask);
+	for (i = 0; i < sizeof (handle_sigs) / sizeof (handle_sigs[0]); i++)
+		if (sigaction (handle_sigs[i], &sa, NULL) == -1) {
+			logger (LOG_ERR, "sigaction: %s", strerror (errno));
+			return (-1);
+		}
 
-	/* We don't care about our childs exit codes right now */
-	signal (SIGCHLD, SIG_IGN);
+	/* Ignore child signals and don't make zombies */
+	sa.sa_handler = SIG_DFL;
+	sa.sa_flags = SA_NOCLDSTOP | SA_NOCLDWAIT;
+	if (sigaction (SIGCHLD, &sa, NULL) == -1) {
+		logger (LOG_ERR, "sigaction: %s", strerror (errno));
+		return (-1);
+	}
 
 	memset (signals, 0, sizeof (signals));
+
+	return (0);
 }
diff --git a/signal.h b/signal.h
index cbd8477b..eccec518 100644
--- a/signal.h
+++ b/signal.h
@@ -28,7 +28,7 @@
 #ifndef SIGNAL_H
 #define SIGNAL_H
 
-void signal_setup (void);
+int signal_setup (void);
 int signal_fd_set (fd_set *rset, int fd);
 int signal_exists (const fd_set *rset);
 int signal_read (fd_set *rset);