a new "dual daemon" operating mode for winbindd

this mode improves the response time of winbindd by having a
background process update the cache while the forground process
responds to queries from cache.

You can enable this mode using the -B command line option. It is quite
experimental, which is why it is not the default.
(This used to be commit c0feff97eefdf5a70e5973e247b395dbdf5d2ef2)

4 files changed, 114 insertions, 50 deletions

diff --git a/source3/Makefile.in b/source3/Makefile.in
index ae89778288..dee2daa6b9 100644
--- a/source3/Makefile.in
+++ b/source3/Makefile.in
@@ -442,7 +442,8 @@ WINBINDD_OBJ1 = \
 		nsswitch/winbindd_cm.o \
 		nsswitch/winbindd_wins.o \
 		nsswitch/winbindd_rpc.o \
-		nsswitch/winbindd_ads.o
+		nsswitch/winbindd_ads.o \
+		nsswitch/winbindd_dual.o
 
 WINBINDD_OBJ = \
 		$(WINBINDD_OBJ1) $(NOPROTO_OBJ) $(PASSDB_OBJ) \
diff --git a/source3/nsswitch/winbindd.c b/source3/nsswitch/winbindd.c
index 479be79574..b198b4a163 100644
--- a/source3/nsswitch/winbindd.c
+++ b/source3/nsswitch/winbindd.c
@@ -4,6 +4,7 @@
    Winbind daemon for ntdom nss module
 
    Copyright (C) by Tim Potter 2000, 2001
+   Copyright (C) Andrew Tridgell 2002
    
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -26,7 +27,8 @@
 
 struct winbindd_cli_state *client_list;
 static int num_clients;
-BOOL opt_nocache;
+BOOL opt_nocache = False;
+BOOL opt_dual_daemon = False;
 
 /* Reload configuration */
 
@@ -365,9 +367,10 @@ static void remove_client(struct winbindd_cli_state *state)
 	}
 }
 
+
 /* Process a complete received packet from a client */
 
-static void process_packet(struct winbindd_cli_state *state)
+void winbind_process_packet(struct winbindd_cli_state *state)
 {
 	/* Process request */
 	
@@ -379,11 +382,16 @@ static void process_packet(struct winbindd_cli_state *state)
 	
 	state->read_buf_len = 0;
 	state->write_buf_len = sizeof(struct winbindd_response);
+
+	/* we might need to send it to the dual daemon */
+	if (opt_dual_daemon) {
+		dual_send_request(state);
+	}
 }
 
 /* Read some data from a client connection */
 
-static void client_read(struct winbindd_cli_state *state)
+void winbind_client_read(struct winbindd_cli_state *state)
 {
 	int n;
     
@@ -397,8 +405,11 @@ static void client_read(struct winbindd_cli_state *state)
 
 	} while (n == -1 && errno == EINTR);
 	
+	DEBUG(10,("client_read: read %d bytes. Need %d more for a full request.\n", n, sizeof(state->request) - n - state->read_buf_len ));
+
+	/* Read failed, kill client */
+	
 	if (n == -1 || n == 0) {
-		/* Read failed, kill client */
 		DEBUG(5,("read failed on sock %d, pid %d: %s\n",
 			 state->sock, state->pid, 
 			 (n == -1) ? strerror(errno) : "EOF"));
@@ -407,8 +418,6 @@ static void client_read(struct winbindd_cli_state *state)
 		return;
 	}
 	
-	DEBUG(10,("client_read: read %d bytes. Need %d more for a full request.\n", n, sizeof(state->request) - n - state->read_buf_len ));
-
 	/* Update client state */
 	
 	state->read_buf_len += n;
@@ -528,6 +537,10 @@ static void process_loop(int accept_sock)
 		timeout.tv_sec = WINBINDD_ESTABLISH_LOOP;
 		timeout.tv_usec = 0;
 
+		if (opt_dual_daemon) {
+			maxfd = dual_select_setup(&w_fds, maxfd);
+		}
+
 		/* Set up client readers and writers */
 
 		state = client_list;
@@ -582,6 +595,10 @@ static void process_loop(int accept_sock)
 
 		if (selret > 0) {
 
+			if (opt_dual_daemon) {
+				dual_select(&w_fds);
+			}
+
 			if (FD_ISSET(accept_sock, &r_fds))
 				new_connection(accept_sock);
             
@@ -595,7 +612,7 @@ static void process_loop(int accept_sock)
                     
 					/* Read data */
                     
-					client_read(state);
+					winbind_client_read(state);
 
 					/* 
 					 * If we have the start of a
@@ -619,7 +636,7 @@ static void process_loop(int accept_sock)
                     
 					if (state->read_buf_len == 
 					    sizeof(state->request)) {
-						process_packet(state);
+						winbind_process_packet(state);
 					}
 				}
                 
@@ -655,6 +672,57 @@ static void process_loop(int accept_sock)
 	}
 }
 
+
+/*
+  these are split out from the main winbindd for use by the background daemon
+ */
+int winbind_setup_common(void)
+{
+	load_interfaces();
+
+	secrets_init();
+
+	/* Get list of domains we look up requests for.  This includes the
+	   domain which we are a member of as well as any trusted
+	   domains. */ 
+
+	init_domain_list();
+
+	ZERO_STRUCT(server_state);
+
+	/* Winbind daemon initialisation */
+
+	if (!winbindd_param_init())
+		return 1;
+
+	if (!winbindd_idmap_init())
+		return 1;
+
+	/* Unblock all signals we are interested in as they may have been
+	   blocked by the parent process. */
+
+	BlockSignals(False, SIGINT);
+	BlockSignals(False, SIGQUIT);
+	BlockSignals(False, SIGTERM);
+	BlockSignals(False, SIGUSR1);
+	BlockSignals(False, SIGUSR2);
+	BlockSignals(False, SIGHUP);
+
+	/* Setup signal handlers */
+	
+	CatchSignal(SIGINT, termination_handler);      /* Exit on these sigs */
+	CatchSignal(SIGQUIT, termination_handler);
+	CatchSignal(SIGTERM, termination_handler);
+
+	CatchSignal(SIGPIPE, SIG_IGN);                 /* Ignore sigpipe */
+
+	CatchSignal(SIGUSR2, sigusr2_handler);         /* Debugging sigs */
+	CatchSignal(SIGHUP, sighup_handler);
+
+	return 0;
+}
+
+
 /* Main function */
 
 struct winbindd_state server_state;   /* Server state information */
@@ -664,6 +732,7 @@ static void usage(void)
 {
 	printf("Usage: winbindd [options]\n");
 	printf("\t-i                interactive mode\n");
+	printf("\t-B                dual daemon mode\n");
 	printf("\t-n                disable cacheing\n");
 	printf("\t-d level          set debug level\n");
 	printf("\t-s configfile     choose smb.conf location\n");
@@ -708,7 +777,7 @@ int main(int argc, char **argv)
 
 	/* Initialise samba/rpc client stuff */
 
-	while ((opt = getopt(argc, argv, "id:s:nh")) != EOF) {
+	while ((opt = getopt(argc, argv, "id:s:nhB")) != EOF) {
 		switch (opt) {
 
 			/* Don't become a daemon */
@@ -716,6 +785,11 @@ int main(int argc, char **argv)
 			interactive = True;
 			break;
 
+			/* dual daemon system */
+		case 'B':
+			opt_dual_daemon = True;
+			break;
+
 			/* disable cacheing */
 		case 'n':
 			opt_nocache = True;
@@ -782,46 +856,13 @@ int main(int argc, char **argv)
 		setpgid( (pid_t)0, (pid_t)0);
 #endif
 
-	load_interfaces();
-
-	secrets_init();
-
-	/* Get list of domains we look up requests for.  This includes the
-	   domain which we are a member of as well as any trusted
-	   domains. */ 
-
-	init_domain_list();
-
-	ZERO_STRUCT(server_state);
-
-	/* Winbind daemon initialisation */
-
-	if (!winbindd_param_init())
-		return 1;
+	if (opt_dual_daemon) {
+		do_dual_daemon();
+	}
 
-	if (!winbindd_idmap_init())
+	if (winbind_setup_common() != 0) {
 		return 1;
-
-	/* Unblock all signals we are interested in as they may have been
-	   blocked by the parent process. */
-
-	BlockSignals(False, SIGINT);
-	BlockSignals(False, SIGQUIT);
-	BlockSignals(False, SIGTERM);
-	BlockSignals(False, SIGUSR1);
-	BlockSignals(False, SIGUSR2);
-	BlockSignals(False, SIGHUP);
-
-	/* Setup signal handlers */
-	
-	CatchSignal(SIGINT, termination_handler);      /* Exit on these sigs */
-	CatchSignal(SIGQUIT, termination_handler);
-	CatchSignal(SIGTERM, termination_handler);
-
-	CatchSignal(SIGPIPE, SIG_IGN);                 /* Ignore sigpipe */
-
-	CatchSignal(SIGUSR2, sigusr2_handler);         /* Debugging sigs */
-	CatchSignal(SIGHUP, sighup_handler);
+	}
 
 	/* Initialise messaging system */
 
diff --git a/source3/nsswitch/winbindd_cache.c b/source3/nsswitch/winbindd_cache.c
index 9bd95fdd86..f65705e0fb 100644
--- a/source3/nsswitch/winbindd_cache.c
+++ b/source3/nsswitch/winbindd_cache.c
@@ -51,7 +51,7 @@ void wcache_flush_cache(void)
 	if (opt_nocache) return;
 
 	wcache->tdb = tdb_open_log(lock_path("winbindd_cache.tdb"), 5000, 
-				   TDB_DEFAULT, O_RDWR | O_CREAT | O_TRUNC, 0600);
+				   TDB_CLEAR_IF_FIRST, O_RDWR|O_CREAT, 0600);
 
 	if (!wcache->tdb) {
 		DEBUG(0,("Failed to open winbindd_cache.tdb!\n"));
@@ -205,11 +205,17 @@ static void refresh_sequence_number(struct winbindd_domain *domain, BOOL force)
 {
 	NTSTATUS status;
 	unsigned time_diff;
+	unsigned cache_time = lp_winbind_cache_time();
+
+	/* trying to reconnect is expensive, don't do it too often */
+	if (domain->sequence_number == DOM_SEQUENCE_NONE) {
+		cache_time *= 8;
+	}
 
 	time_diff = time(NULL) - domain->last_seq_check;
 
 	/* see if we have to refetch the domain sequence number */
-	if (!force && (time_diff < lp_winbind_cache_time())) {
+	if (!force && (time_diff < cache_time)) {
 		return;
 	}
 
@@ -289,9 +295,15 @@ static struct cache_entry *wcache_fetch(struct winbind_cache *cache,
 	centry->sequence_number = centry_uint32(centry);
 
 	if (centry_expired(domain, centry)) {
+		extern BOOL opt_dual_daemon;
+		if (opt_dual_daemon) {
+			extern BOOL backgroud_process;
+			backgroud_process = True;
+		} else {
 		centry_free(centry);
 		return NULL;
 	}
+	}
 
 	return centry;
 }
diff --git a/source3/nsswitch/winbindd_proto.h b/source3/nsswitch/winbindd_proto.h
index f3830cd63c..8cac542b88 100644
--- a/source3/nsswitch/winbindd_proto.h
+++ b/source3/nsswitch/winbindd_proto.h
@@ -6,6 +6,9 @@
 
 /* The following definitions come from nsswitch/winbindd.c  */
 
+void winbind_process_packet(struct winbindd_cli_state *state);
+void winbind_client_read(struct winbindd_cli_state *state);
+int winbind_setup_common(void);
 int main(int argc, char **argv);
 
 /* The following definitions come from nsswitch/winbindd_ads.c  */
@@ -39,6 +42,13 @@ NTSTATUS cm_get_netlogon_cli(char *domain, unsigned char *trust_passwd,
 			     struct cli_state **cli);
 void winbindd_cm_status(void);
 
+/* The following definitions come from nsswitch/winbindd_dual.c  */
+
+int dual_select_setup(fd_set *fds, int maxfd);
+void dual_select(fd_set *fds);
+void dual_send_request(struct winbindd_cli_state *state);
+void do_dual_daemon(void);
+
 /* The following definitions come from nsswitch/winbindd_group.c  */
 
 enum winbindd_result winbindd_getgrnam(struct winbindd_cli_state *state);