pid file support

bin/named/server.c

@@ -603,7 +603,9 @@ configure_server_querysource(dns_c_ctx_t *cctx, ns_server_t *server,
 }
 
 static isc_result_t
-load_configuration(const char *filename, ns_server_t *server) {
+load_configuration(const char *filename, ns_server_t *server,
+		   isc_boolean_t first_time)
+{
 	isc_result_t result;
 	ns_load_t lctx;
 	dns_c_cbks_t callbacks;
@@ -612,6 +614,7 @@ load_configuration(const char *filename, ns_server_t *server) {
 	dns_viewlist_t tmpviewlist;
 	dns_aclconfctx_t aclconfctx;
 	dns_dispatch_t *dispatch;
+	char *pidfilename;
 
 	dns_aclconfctx_init(&aclconfctx);
 
@@ -776,6 +779,14 @@ load_configuration(const char *filename, ns_server_t *server) {
 			dns_tkeyctx_destroy(&server->tkeyctx);
 		server->tkeyctx = t;
 	}
+
+	if (first_time)
+		ns_os_changeuser(ns_g_username);
+
+	if (dns_c_ctx_getpidfilename(configctx, &pidfilename) ==
+	    ISC_R_NOTFOUND)
+		pidfilename = "/var/run/named.pid";
+	ns_os_writepidfile(pidfilename);
 	
 	dns_aclconfctx_destroy(&aclconfctx);	
 
@@ -833,6 +844,7 @@ static void
 run_server(isc_task_t *task, isc_event_t *event) {
 	isc_result_t result;
 	ns_server_t *server = (ns_server_t *) event->arg;
+
 	(void)task;
 
 	isc_event_free(&event);
@@ -846,19 +858,12 @@ run_server(isc_task_t *task, isc_event_t *event) {
 					  &server->interfacemgr),
 		   "creating interface manager");
 
-	CHECKFATAL(load_configuration(ns_g_conffile, server),
+	CHECKFATAL(load_configuration(ns_g_conffile, server, ISC_TRUE),
 		   "loading configuration");
 
 	CHECKFATAL(load_zones(server, ISC_TRUE),
 		   "loading zones");
 
-	/*
-	 * XXXRTH  Currently ns_os_changeuser() will call ns_main_earlyfatal()
-	 *         if it fails.  Perhaps it should be changed to return an
-	 *         error code?
-	 */
-	ns_os_changeuser(ns_g_username);
-
 	isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
 		      ISC_LOG_INFO, "running");
 }
@@ -1021,7 +1026,7 @@ ns_server_reload(isc_task_t *task, isc_event_t *event) {
 	ns_server_t *server = (ns_server_t *) event->arg;
 	UNUSED(task);
 	
-	result = load_configuration(ns_g_conffile, server);
+	result = load_configuration(ns_g_conffile, server, ISC_FALSE);
 	if (result != DNS_R_SUCCESS) {
 		isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
 			      NS_LOGMODULE_SERVER, ISC_LOG_ERROR,

bin/named/unix/include/named/os.h

@@ -26,13 +26,16 @@ ns_os_init(void);
 void
 ns_os_daemonize(void);
 
-void
-ns_os_shutdown(void);
-
 void
 ns_os_chroot(const char *root);
 
 void
 ns_os_changeuser(const char *username);
 
+void
+ns_os_writepidfile(const char *filename);
+
+void
+ns_os_shutdown(void);
+
 #endif /* NS_OS_H */

bin/named/unix/os.c

@@ -18,6 +18,7 @@
 #include <config.h>
 
 #include <sys/types.h>
+#include <sys/stat.h>
 
 #include <ctype.h>
 #include <stdio.h>
@@ -36,6 +37,10 @@
 #include <named/main.h>
 #include <named/os.h>
 
+static char *pidfile = NULL;
+#ifdef HAVE_LINUXTHREADS
+static pid_t mainpid = 0;
+#endif
 
 #ifdef HAVE_LINUX_CAPABILITY_H
 
@@ -119,6 +124,9 @@ ns_os_init(void) {
 #ifdef HAVE_LINUX_CAPABILITY_H
 	linux_initialprivs();
 #endif
+#ifdef HAVE_LINUXTHREADS
+	mainpid = getpid();
+#endif
 }
 
 void
@@ -136,6 +144,10 @@ ns_os_daemonize(void) {
 	 * We're the child.
 	 */
 
+#ifdef HAVE_LINUXTHREADS
+	mainpid = getpid();
+#endif
+
         if (setsid() == -1)
 		ns_main_earlyfatal("setsid(): %s", strerror(errno));
 
@@ -155,12 +167,6 @@ ns_os_daemonize(void) {
 	}
 }
 
-void
-ns_os_shutdown(void) {
-	closelog();
-}
-
-
 static isc_boolean_t
 all_digits(const char *s) {
 	if (*s == '\0')
@@ -211,3 +217,75 @@ ns_os_changeuser(const char *username) {
 	if (setuid(pw->pw_uid) < 0)
 		ns_main_earlyfatal("setuid(): %s", strerror(errno));
 }
+
+static int
+safe_open(const char *filename) {
+        struct stat sb;
+
+        if (stat(filename, &sb) == -1) {
+                if (errno != ENOENT)
+			return (-1);
+        } else if ((sb.st_mode & S_IFREG) == 0)
+		return (-1);
+
+        (void)unlink(filename);
+        return (open(filename, O_WRONLY|O_CREAT|O_EXCL,
+		     S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH));
+}
+
+static void
+cleanup_pidfile(void) {
+	if (pidfile != NULL)
+		(void)unlink(pidfile);
+	free(pidfile);
+	pidfile = NULL;
+}
+
+void
+ns_os_writepidfile(const char *filename) {
+        int fd;
+	FILE *lockfile;
+	size_t len;
+	pid_t pid;
+
+	/*
+	 * The caller must ensure any required synchronization.
+	 */
+
+	cleanup_pidfile();
+
+	len = strlen(filename);
+	pidfile = malloc(len + 1);
+	if (pidfile == NULL)
+                ns_main_earlyfatal("couldn't malloc '%s': %s",
+				   filename, strerror(errno));
+	/* This is safe. */
+	strcpy(pidfile, filename);
+
+        fd = safe_open(filename);
+        if (fd < 0)
+                ns_main_earlyfatal("couldn't open pid file '%s': %s",
+				   filename, strerror(errno));
+        lockfile = fdopen(fd, "w");
+        if (lockfile == NULL)
+		ns_main_earlyfatal("could not fdopen() pid file '%s': %s",
+				   filename, strerror(errno));
+#ifdef HAVE_LINUXTHREADS
+	pid = mainpid;
+#else
+	pid = getpid();
+#endif
+        if (fprintf(lockfile, "%ld\n", (long)pid) < 0)
+                ns_main_earlyfatal("fprintf() to pid file '%s' failed",
+				   filename);
+        if (fflush(lockfile) == EOF)
+                ns_main_earlyfatal("fflush() to pid file '%s' failed",
+				   filename);
+	(void)fclose(lockfile);
+}
+
+void
+ns_os_shutdown(void) {
+	closelog();
+	cleanup_pidfile();
+}