Remaining changes to implement the prefork process model

To use, run 'smbd -M prefork'

By default, only the smb service is preforked.  4 children are
created, and all listen for new connections.  The Linux Kernel 'wake
one' behaviour should ensure that only one is given the oportunity to
accept.  We need to look into the ideal number of worker children, as
well as load balancing behaviours.

To change, set:

prefork children : smb = 6

valid service names (smb in this example) match those in 'server services'.

Andrew Bartlett and David Disseldorp
(This used to be commit 35313c0aa3fbfdd943edfb7bafd7645b1a0c54e9)

5 files changed, 248 insertions, 9 deletions

diff --git a/source4/smbd/process_model.h b/source4/smbd/process_model.h
index c2a5c9e9e8..796c8ee17b 100644
--- a/source4/smbd/process_model.h
+++ b/source4/smbd/process_model.h
@@ -25,7 +25,7 @@
 #define __PROCESS_MODEL_H__
 
 #include "lib/socket/socket.h"
-#include "smbd/service_task.h"
+#include "smbd/service.h"
 
 /* modules can use the following to determine if the interface has changed
  * please increment the version number after each interface change
@@ -56,6 +56,7 @@ struct model_ops {
 	/* function to create a task */
 	void (*new_task)(struct event_context *, 
 			 struct loadparm_context *lp_ctx, 
+			 const char *service_name,
 			 void (*)(struct event_context *, 
 				  struct loadparm_context *, struct server_id, 
 				  void *),
diff --git a/source4/smbd/process_model.mk b/source4/smbd/process_model.mk
index d6b7698e74..5201a2e46e 100644
--- a/source4/smbd/process_model.mk
+++ b/source4/smbd/process_model.mk
@@ -32,6 +32,16 @@ PRIVATE_DEPENDENCIES = PTHREAD
 # End MODULE process_model_thread
 ################################################
 
+################################################
+# Start MODULE process_model_prefork
+[MODULE::process_model_prefork]
+INIT_FUNCTION = process_model_prefork_init 
+SUBSYSTEM = process_model
+OBJ_FILES = \
+		process_prefork.o
+# End MODULE process_model_thread
+################################################
+
 [SUBSYSTEM::process_model]
 PRIVATE_PROTO_HEADER = process_model_proto.h
 OBJ_FILES = \
diff --git a/source4/smbd/process_prefork.c b/source4/smbd/process_prefork.c
new file mode 100644
index 0000000000..9f975b4641
--- /dev/null
+++ b/source4/smbd/process_prefork.c
@@ -0,0 +1,226 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   process model: prefork (n client connections per process)
+
+   Copyright (C) Andrew Tridgell 1992-2005
+   Copyright (C) James J Myers 2003 <myersjj@samba.org>
+   Copyright (C) Stefan (metze) Metzmacher 2004
+   Copyright (C) Andrew Bartlett 2008 <abartlet@samba.org>
+   Copyright (C) David Disseldorp 2008 <ddiss@sgi.com>
+   
+   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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "lib/events/events.h"
+#include "lib/tdb/include/tdb.h"
+#include "lib/socket/socket.h"
+#include "smbd/process_model.h"
+#include "param/secrets.h"
+#include "system/filesys.h"
+#include "cluster/cluster.h"
+#include "param/param.h"
+
+#ifdef HAVE_SETPROCTITLE
+#ifdef HAVE_SETPROCTITLE_H
+#include <setproctitle.h>
+#endif
+#else
+#define setproctitle none_setproctitle
+static int none_setproctitle(const char *fmt, ...) PRINTF_ATTRIBUTE(1, 2);
+static int none_setproctitle(const char *fmt, ...)
+{
+	return 0;
+}
+#endif
+
+/*
+  called when the process model is selected
+*/
+static void prefork_model_init(struct event_context *ev)
+{
+	signal(SIGCHLD, SIG_IGN);
+}
+
+/*
+  called when a listening socket becomes readable. 
+*/
+static void prefork_accept_connection(struct event_context *ev, 
+				       struct loadparm_context *lp_ctx,
+				       struct socket_context *sock, 
+				       void (*new_conn)(struct event_context *,
+							struct loadparm_context *, struct socket_context *, 
+							struct server_id , void *), 
+				       void *private)
+{
+	NTSTATUS status;
+	struct socket_context *sock2;
+	pid_t pid = getpid();
+
+	/* accept an incoming connection. */
+	status = socket_accept(sock, &sock2);
+	if (!NT_STATUS_IS_OK(status)) {
+		return;
+	}
+
+	talloc_steal(private, sock);
+
+	new_conn(ev, lp_ctx, sock2, cluster_id(pid, socket_get_fd(sock2)), private);
+}
+
+/*
+  called to create a new server task
+*/
+static void prefork_new_task(struct event_context *ev, 
+			     struct loadparm_context *lp_ctx,
+			     const char *service_name,
+			     void (*new_task_fn)(struct event_context *, struct loadparm_context *lp_ctx, struct server_id , void *), 
+			     void *private)
+{
+	pid_t pid;
+	int i, num_children;
+
+	struct event_context *ev2, *ev_parent;
+
+	pid = fork();
+
+	if (pid != 0) {
+		/* parent or error code ... go back to the event loop */
+		return;
+	}
+
+	pid = getpid();
+
+	/* This is now the child code. We need a completely new event_context to work with */
+	ev2 = event_context_init(NULL);
+
+	/* the service has given us a private pointer that
+	   encapsulates the context it needs for this new connection -
+	   everything else will be freed */
+	talloc_steal(ev2, private);
+
+	/* this will free all the listening sockets and all state that
+	   is not associated with this new connection */
+	talloc_free(ev);
+
+	/* tdb needs special fork handling */
+	if (tdb_reopen_all(1) == -1) {
+		DEBUG(0,("prefork_accept_connection: tdb_reopen_all failed.\n"));
+	}
+
+	/* Ensure that the forked children do not expose identical random streams */
+	set_need_random_reseed();
+
+	setproctitle("task %s server_id[%d]", service_name, pid);
+
+	/* setup this new connection: process will bind to it's sockets etc */
+	new_task_fn(ev2, lp_ctx, cluster_id(pid, 0), private);
+
+	num_children = lp_parm_int(lp_ctx, NULL, "prefork children", service_name, 0);
+	if (num_children == 0) {
+
+		/* We don't want any kids hanging around for this one,
+		 * let the parent do all the work */
+		event_loop_wait(ev2);
+		
+		talloc_free(ev2);
+		exit(0);
+	}
+
+	/* We are now free to spawn some child proccesses */
+
+	for (i=0; i < num_children; i++) {
+
+		pid = fork();
+		if (pid > 0) {
+			continue;
+		} else if (pid == -1) {
+			return;
+		} else {
+			pid = getpid();
+			setproctitle("task %s server_id[%d]", service_name, pid);
+			/* we can't return to the top level here, as that event context is gone,
+			   so we now process events in the new event context until there are no
+			   more to process */	   
+			event_loop_wait(ev2);
+			
+			talloc_free(ev2);
+			exit(0);
+		}
+	}
+
+	/* Don't listen on the sockets we just gave to the children */
+	talloc_free(ev2);
+	
+	/* But we need a events system to handle reaping children */
+	ev_parent = event_context_init(NULL);
+	
+	/* TODO: Handle some events... */
+	
+	/* we can't return to the top level here, as that event context is gone,
+	   so we now process events in the new event context until there are no
+	   more to process */	   
+	event_loop_wait(ev_parent);
+	
+	talloc_free(ev_parent);
+	exit(0);
+
+}
+
+
+/* called when a task goes down */
+_NORETURN_ static void prefork_terminate(struct event_context *ev, const char *reason) 
+{
+	DEBUG(2,("prefork_terminate: reason[%s]\n",reason));
+
+	/* this reload_charcnv() has the effect of freeing the iconv context memory,
+	   which makes leak checking easier */
+	reload_charcnv(global_loadparm);
+
+	/* the secrets db should really hang off the connection structure */
+	secrets_shutdown();
+
+	talloc_free(ev);
+
+	/* terminate this process */
+	exit(0);
+}
+
+/* called to set a title of a task or connection */
+static void prefork_set_title(struct event_context *ev, const char *title) 
+{
+	if (title) {
+		setproctitle("%s", title);
+	} else {
+		setproctitle(NULL);
+	}
+}
+
+static const struct model_ops prefork_ops = {
+	.name			= "prefork",
+	.model_init		= prefork_model_init,
+	.accept_connection	= prefork_accept_connection,
+	.new_task               = prefork_new_task,
+	.terminate              = prefork_terminate,
+	.set_title              = prefork_set_title,
+};
+
+/*
+  initialise the prefork process model, registering ourselves with the process model subsystem
+ */
+NTSTATUS process_model_prefork_init(void)
+{
+	return register_process_model(&prefork_ops);
+}
diff --git a/source4/smbd/process_standard.c b/source4/smbd/process_standard.c
index c088ea3b1a..deb44c0a68 100644
--- a/source4/smbd/process_standard.c
+++ b/source4/smbd/process_standard.c
@@ -127,8 +127,8 @@ static void standard_accept_connection(struct event_context *ev,
 	talloc_free(c);
 	talloc_free(s);
 
-	/* setup this new connection */
-	new_conn(ev2, lp_ctx, sock2, cluster_id(pid), private);
+	/* setup this new connection.  Cluster ID is PID based for this process modal */
+	new_conn(ev2, lp_ctx, sock2, cluster_id(pid, 0), private);
 
 	/* we can't return to the top level here, as that event context is gone,
 	   so we now process events in the new event context until there are no
@@ -144,6 +144,7 @@ static void standard_accept_connection(struct event_context *ev,
 */
 static void standard_new_task(struct event_context *ev, 
 			      struct loadparm_context *lp_ctx,
+			      const char *service_name,
 			      void (*new_task)(struct event_context *, struct loadparm_context *lp_ctx, struct server_id , void *), 
 			      void *private)
 {
@@ -179,10 +180,10 @@ static void standard_new_task(struct event_context *ev,
 	/* Ensure that the forked children do not expose identical random streams */
 	set_need_random_reseed();
 
-	setproctitle("task server_id[%d]", pid);
+	setproctitle("task %s server_id[%d]", service_name, pid);
 
-	/* setup this new connection */
-	new_task(ev2, lp_ctx, cluster_id(pid), private);
+	/* setup this new task.  Cluster ID is PID based for this process modal */
+	new_task(ev2, lp_ctx, cluster_id(pid, 0), private);
 
 	/* we can't return to the top level here, as that event context is gone,
 	   so we now process events in the new event context until there are no
diff --git a/source4/smbd/process_thread.c b/source4/smbd/process_thread.c
index 6c5f4816c0..5a45cdfeac 100644
--- a/source4/smbd/process_thread.c
+++ b/source4/smbd/process_thread.c
@@ -148,6 +148,7 @@ static void *thread_task_fn(void *thread_parm)
 */
 static void thread_new_task(struct event_context *ev, 
 			    struct loadparm_context *lp_ctx,
+			    const char *service_name,
 			    void (*new_task)(struct event_context *, 
 					     struct loadparm_context *,
 					     uint32_t , void *), 
@@ -178,10 +179,10 @@ static void thread_new_task(struct event_context *ev,
 	rc = pthread_create(&thread_id, &thread_attr, thread_task_fn, state);
 	pthread_attr_destroy(&thread_attr);
 	if (rc == 0) {
-		DEBUG(4,("thread_new_task: created thread_id=%lu\n", 
-			 (unsigned long int)thread_id));
+		DEBUG(4,("thread_new_task: created %s thread_id=%lu\n", 
+			 service_name, (unsigned long int)thread_id));
 	} else {
-		DEBUG(0,("thread_new_task: thread create failed rc=%d\n", rc));
+		DEBUG(0,("thread_new_task: thread create for %s failed rc=%d\n", service_name, rc));
 		talloc_free(ev2);
 	}
 }