3 files changed, 454 insertions, 0 deletions
diff --git a/source4/lib/messaging/config.m4 b/source4/lib/messaging/config.m4
new file mode 100644
index 0000000000..1797069ff2
--- /dev/null
+++ b/source4/lib/messaging/config.m4
@@ -0,0 +1 @@
+SMB_SUBSYSTEM_MK(MESSAGING,lib/messaging/config.mk)
diff --git a/source4/lib/messaging/config.mk b/source4/lib/messaging/config.mk
new file mode 100644
index 0000000000..6c30894779
--- /dev/null
+++ b/source4/lib/messaging/config.mk
@@ -0,0 +1,8 @@
+
+################################################
+# Start SUBSYSTEM MESSAGING
+[SUBSYSTEM::MESSAGING]
+INIT_OBJ_FILES = \
+		lib/messaging/messaging.o
+# End SUBSYSTEM MESSAGING
+################################################
diff --git a/source4/lib/messaging/messaging.c b/source4/lib/messaging/messaging.c
new file mode 100644
index 0000000000..f9caf5071c
--- /dev/null
+++ b/source4/lib/messaging/messaging.c
@@ -0,0 +1,445 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   Samba internal messaging functions
+
+   Copyright (C) Andrew Tridgell 2004
+   
+   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 2 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, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+
+/* change the message version with any incompatible changes in the protocol */
+#define MESSAGING_VERSION 1
+
+struct messaging_state {
+	servid_t server_id;
+	struct socket_context *sock;
+	char *path;
+	struct dispatch_fn *dispatch;
+
+	struct {
+		struct event_context *ev;
+		struct fd_event *fde;
+	} event;
+};
+
+/* we have a linked list of dispatch handlers that this messaging
+   server can deal with */
+struct dispatch_fn {
+	struct dispatch_fn *next, *prev;
+	uint32_t msg_type;
+	void *private;
+	void (*fn)(void *msg_ctx, void *private, 
+		   uint32_t msg_type, servid_t server_id, DATA_BLOB *data);
+};
+
+/* an individual message */
+struct messaging_rec {
+	struct messaging_rec *next, *prev;
+
+	struct messaging_state *msg;
+	struct socket_context *sock;
+	struct fd_event *fde;
+	const char *path;
+
+	struct {
+		uint32_t version;
+		uint32_t msg_type;
+		servid_t from;
+		servid_t to;
+		uint32_t length;
+	} header;
+
+	DATA_BLOB data;
+
+	uint32_t ndone;
+};
+
+/*
+ A useful function for testing the message system.
+*/
+static void ping_message(void *msg_ctx, void *private, 
+			 uint32_t msg_type, servid_t src, DATA_BLOB *data)
+{
+	DEBUG(1,("INFO: Received PING message from server %u [%.*s]\n",
+		 (uint_t)src, data->length, data->data?(const char *)data->data:""));
+	messaging_send(msg_ctx, src, MSG_PONG, data);
+}
+
+/* 
+   return the path to a messaging socket
+*/
+static char *messaging_path(TALLOC_CTX *mem_ctx, servid_t server_id)
+{
+	char *name = talloc_asprintf(mem_ctx, "messaging/msg.%u", (unsigned)server_id);
+	char *ret;
+	ret = lock_path(mem_ctx, name);
+	talloc_free(name);
+	return ret;
+}
+
+/*
+  dispatch a fully received message
+*/
+static void messaging_dispatch(struct messaging_state *msg, struct messaging_rec *rec)
+{
+	struct dispatch_fn *d;
+	for (d=msg->dispatch;d;d=d->next) {
+		if (d->msg_type == rec->header.msg_type) {
+			d->fn(msg, d->private, d->msg_type, rec->header.from, &rec->data);
+		}
+	}
+
+	/* we don't free the record itself here as there may
+	   be more messages from this client */
+	data_blob_free(&rec->data);
+	rec->header.length = 0;
+	rec->ndone = 0;
+}
+
+
+/*
+  handle IO for a single message
+*/
+static void messaging_recv_handler(struct event_context *ev, struct fd_event *fde, 
+				 time_t t, uint16_t flags)
+{
+	struct messaging_rec *rec = fde->private;
+	struct messaging_state *msg = rec->msg;
+	NTSTATUS status;
+
+	if (rec->ndone < sizeof(rec->header)) {
+		/* receive the header */
+		DATA_BLOB blob;
+		status = socket_recv(rec->sock, rec, 
+				     &blob, sizeof(rec->header) - rec->ndone, 0);
+		if (NT_STATUS_IS_ERR(status)) {
+			talloc_free(rec);
+			return;
+		}
+
+		if (blob.length == 0) {
+			return;
+		}
+
+		memcpy(rec->ndone + (char *)&rec->header, blob.data, blob.length);
+		rec->ndone += blob.length;
+		data_blob_free(&blob);
+
+		if (rec->ndone == sizeof(rec->header)) {
+			if (rec->header.version != MESSAGING_VERSION) {
+				DEBUG(0,("meessage with wrong version %u\n",
+					 rec->header.version));
+				talloc_free(rec);
+			}
+			rec->data = data_blob_talloc(rec, NULL, rec->header.length);
+			if (rec->data.length != rec->header.length) {
+				DEBUG(0,("Unable to allocate message of size %u\n",
+					 rec->header.length));
+				talloc_free(rec);
+			}
+		}
+	}
+
+	if (rec->ndone >= sizeof(rec->header) && 
+	    rec->ndone < sizeof(rec->header) + rec->header.length) {
+		/* receive the body, if any */
+		DATA_BLOB blob;
+		status = socket_recv(rec->sock, rec, 
+				     &blob, sizeof(rec->header) + rec->header.length - rec->ndone, 0);
+		if (NT_STATUS_IS_ERR(status)) {
+			talloc_free(rec);
+			return;
+		}
+
+		if (blob.length == 0) {
+			return;
+		}
+
+		memcpy(rec->data.data + (rec->ndone - sizeof(rec->header)), 
+		       blob.data, blob.length);
+
+		rec->ndone += blob.length;
+	}
+
+	if (rec->ndone == sizeof(rec->header) + rec->header.length) {
+		/* we've got the whole message */
+		messaging_dispatch(msg, rec);
+	}
+}
+
+/*
+  destroy a messaging record
+*/
+static int rec_destructor(void *ptr)
+{
+	struct messaging_rec *rec = ptr;
+	struct messaging_state *msg = rec->msg;
+	event_remove_fd(msg->event.ev, rec->fde);
+	return 0;
+}
+
+/*
+  handle a new incoming connection
+*/
+static void messaging_listen_handler(struct event_context *ev, struct fd_event *fde, 
+				     time_t t, uint16_t flags)
+{
+	struct messaging_state *msg = fde->private;
+	struct messaging_rec *rec;
+	NTSTATUS status;
+	struct fd_event fde2;
+
+	rec = talloc_p(msg, struct messaging_rec);
+	if (rec == NULL) {
+		smb_panic("Unable to allocate messaging_rec");
+	}
+
+	status = socket_accept(msg->sock, &rec->sock, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		smb_panic("Unable to accept messaging_rec");
+	}
+	talloc_steal(rec, rec->sock);
+
+	rec->msg = msg;
+	rec->ndone = 0;
+	rec->header.length = 0;
+	rec->path = msg->path;
+
+	fde2.private 	= rec;
+	fde2.fd		= socket_get_fd(rec->sock);
+	fde2.flags	= EVENT_FD_READ;
+	fde2.handler	= messaging_recv_handler;
+
+	rec->fde	= event_add_fd(msg->event.ev, &fde2);
+
+	talloc_set_destructor(rec, rec_destructor);
+}
+
+/*
+  Register a dispatch function for a particular message type.
+*/
+void messaging_register(void *ctx, void *private,
+			uint32_t msg_type, 
+			void (*fn)(void *, void *, uint32_t, servid_t, DATA_BLOB *))
+{
+	struct messaging_state *msg = ctx;
+	struct dispatch_fn *d;
+
+	d = talloc_p(msg, struct dispatch_fn);
+	d->msg_type = msg_type;
+	d->private = private;
+	d->fn = fn;
+	DLIST_ADD(msg->dispatch, d);
+}
+
+/*
+  De-register the function for a particular message type.
+*/
+void messaging_deregister(void *ctx, uint32_t msg_type)
+{
+	struct messaging_state *msg = ctx;
+	struct dispatch_fn *d, *next;
+
+	for (d = msg->dispatch; d; d = next) {
+		next = d->next;
+		if (d->msg_type == msg_type) {
+			DLIST_REMOVE(msg->dispatch, d);
+			talloc_free(d);
+		}
+	}	
+}
+
+
+
+/*
+  handle IO for sending a message
+*/
+static void messaging_send_handler(struct event_context *ev, struct fd_event *fde, 
+				   time_t t, uint16_t flags)
+{
+	struct messaging_rec *rec = fde->private;
+	NTSTATUS status;
+
+	if (rec->ndone < sizeof(rec->header)) {
+		/* send the header */
+		size_t nsent;
+		DATA_BLOB blob;
+
+		blob.data = rec->ndone + (char *)&rec->header;
+		blob.length = sizeof(rec->header) - rec->ndone;
+
+		status = socket_send(rec->sock, rec, &blob, &nsent, 0);
+		if (NT_STATUS_IS_ERR(status)) {
+			talloc_free(rec);
+			return;
+		}
+
+		if (nsent == 0) {
+			return;
+		}
+
+		rec->ndone += nsent;
+	}
+
+	if (rec->ndone >= sizeof(rec->header) && 
+	    rec->ndone < sizeof(rec->header) + rec->header.length) {
+		/* send the body, if any */
+		DATA_BLOB blob;
+		size_t nsent;
+
+		blob.data = rec->data.data + (rec->ndone - sizeof(rec->header));
+		blob.length = rec->header.length - (rec->ndone - sizeof(rec->header));
+
+		status = socket_send(rec->sock, rec, &blob, &nsent, 0);
+		if (NT_STATUS_IS_ERR(status)) {
+			talloc_free(rec);
+			return;
+		}
+
+		rec->ndone += nsent;
+	}
+
+	if (rec->ndone == sizeof(rec->header) + rec->header.length) {
+		/* we've done the whole message */
+		talloc_free(rec);
+	}
+}
+
+
+/*
+  Send a message to a particular server
+*/
+NTSTATUS messaging_send(void *msg_ctx, servid_t server, uint32_t msg_type, DATA_BLOB *data)
+{
+	struct messaging_state *msg = msg_ctx;
+	struct messaging_rec *rec;
+	NTSTATUS status;
+	struct fd_event fde;
+
+	rec = talloc_p(msg, struct messaging_rec);
+	if (rec == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	rec->msg = msg;
+	rec->header.version = MESSAGING_VERSION;
+	rec->header.msg_type = msg_type;
+	rec->header.from = msg->server_id;
+	rec->header.to = server;
+	rec->header.length = data?data->length:0;
+	if (rec->header.length != 0) {
+		rec->data = data_blob_talloc(rec, data->data, data->length);
+	} else {
+		rec->data = data_blob(NULL, 0);
+	}
+	rec->ndone = 0;
+
+	status = socket_create("unix", SOCKET_TYPE_STREAM, &rec->sock, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(rec);
+		return status;
+	}
+	talloc_steal(rec, rec->sock);
+
+	rec->path = messaging_path(rec, server);
+
+	status = socket_connect(rec->sock, NULL, 0, rec->path, 0, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(rec);
+		return status;
+	}
+
+	fde.private 	= rec;
+	fde.fd		= socket_get_fd(rec->sock);
+	fde.flags	= EVENT_FD_WRITE;
+	fde.handler	= messaging_send_handler;
+
+	rec->fde	= event_add_fd(msg->event.ev, &fde);
+
+	talloc_set_destructor(rec, rec_destructor);
+
+	return NT_STATUS_OK;
+}
+
+
+/*
+  destroy the messaging context
+*/
+static int messaging_destructor(void *msg_ctx)
+{
+	struct messaging_state *msg = msg_ctx;
+	event_remove_fd(msg->event.ev, msg->event.fde);
+	return 0;
+}
+
+/*
+  create the listening socket and setup the dispatcher
+*/
+void *messaging_init(TALLOC_CTX *mem_ctx, servid_t server_id, struct event_context *ev)
+{
+	struct messaging_state *msg;
+	NTSTATUS status;
+	struct fd_event fde;
+
+	msg = talloc_p(mem_ctx, struct messaging_state);
+	if (msg == NULL) {
+		return NULL;
+	}
+
+	/* create the messaging directory if needed */
+	msg->path = lock_path(msg, "messaging");
+	mkdir(msg->path, 0700);
+	talloc_free(msg->path);
+
+	msg->server_id = server_id;
+	msg->dispatch = NULL;
+	msg->path = messaging_path(msg, server_id);
+
+	status = socket_create("unix", SOCKET_TYPE_STREAM, &msg->sock, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(msg);
+		return NULL;
+	}
+
+	/* by stealing here we ensure that the socket is cleaned up (and even 
+	   deleted) on exit */
+	talloc_steal(msg, msg->sock);
+
+	status = socket_listen(msg->sock, msg->path, 0, 50, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0,("Unable to setup messaging listener for '%s'\n", msg->path));
+		talloc_free(msg);
+		return NULL;
+	}
+
+	fde.private 	= msg;
+	fde.fd		= socket_get_fd(msg->sock);
+	fde.flags	= EVENT_FD_READ;
+	fde.handler	= messaging_listen_handler;
+
+	msg->event.ev   = ev;
+	msg->event.fde	= event_add_fd(ev, &fde);
+
+	talloc_set_destructor(msg, messaging_destructor);
+	
+	messaging_register(msg, NULL, MSG_PING, ping_message);
+
+	return msg;
+}
+
+