[master] Add code to remove pid files and to log killing of clients

RELNOTES

@@ -103,6 +103,11 @@ by Eric Young (eay@cryptsoft.com).
   Thanks to Jiri Popelka at Red Hat for the bug and fix.
   [ISC-Bugs #21238
 
+- Add a log entry when killing a client and remove the PID files
+  when a server, relay or client are killed.
+  [ISC-Bugs #16970]
+  [ISC-Bugs #17258]
+
 			Changes since 4.3.0rc1
 
 - None

client/dhclient.c

@@ -408,8 +408,10 @@ main(int argc, char **argv) {
 			e = fscanf(pidfd, "%ld\n", &temp);
 			oldpid = (pid_t)temp;
 
-			if (e != 0 && e != EOF) {
+			if (e != 0 && e != EOF && oldpid) {
-				if (oldpid && (kill(oldpid, SIGTERM) == 0)) {
+				if (kill(oldpid, SIGTERM) == 0) {
+					log_info("Killed old client process");
+					(void) unlink(path_dhclient_pid);
 					/*
 					 * wait for the old process to
 					 * cleanly terminate.
@@ -418,6 +420,9 @@ main(int argc, char **argv) {
 					 * the parent can be signaled...
 					 */
 					sleep(1);
+				} else if (errno == ESRCH) {
+					log_info("Removed stale PID file");
+					(void) unlink(path_dhclient_pid);
 				}
 			}
 			fclose(pidfd);
@@ -3867,6 +3872,9 @@ unsigned cons_agent_information_options (cfg_options, outpacket,
 
 static void shutdown_exit (void *foo)
 {
+	/* get rid of the pid if we can */
+	if (no_pid_file == ISC_FALSE)
+		(void) unlink(path_dhclient_pid);
 	exit (0);
 }
 

relay/dhcrelay.c

@@ -1717,5 +1717,9 @@ dhcp_set_control_state(control_object_state_t oldstate,
 		       control_object_state_t newstate) {
 	if (newstate != server_shutdown)
 		return ISC_R_SUCCESS;
+
+	if (no_pid_file == ISC_FALSE)
+		(void) unlink(path_dhcrelay_pid);
+
 	exit(0);
 }

server/dhcpd.c

@@ -1354,6 +1354,8 @@ static isc_result_t dhcp_io_shutdown_countdown (void *vlp)
 	    free_everything ();
 	    omapi_print_dmalloc_usage_by_caller ();
 #endif
+	    if (no_pid_file == ISC_FALSE)
+		    (void) unlink(path_dhcpd_pid);
 	    exit (0);
 	}		
 #else
@@ -1363,6 +1365,8 @@ static isc_result_t dhcp_io_shutdown_countdown (void *vlp)
 		free_everything ();
 		omapi_print_dmalloc_usage_by_caller (); 
 #endif
+		if (no_pid_file == ISC_FALSE)
+			(void) unlink(path_dhcpd_pid);
 		exit (0);
 	}
 #endif