2 Unix SMB/CIFS implementation.
3 Samba internal messaging functions
4 Copyright (C) Andrew Tridgell 2000
5 Copyright (C) 2001 by Martin Pool
6 Copyright (C) 2002 by Jeremy Allison
7 Copyright (C) 2007 by Volker Lendecke
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 @defgroup messages Internal messaging framework
29 @brief Module for internal messaging between Samba daemons.
31 The idea is that if a part of Samba wants to do communication with
32 another Samba process then it will do a message_register() of a
33 dispatch function, and use message_send_pid() to send messages to
36 The dispatch function is given the pid of the sender, and it can
37 use that to reply by message_send_pid(). See ping_message() for a
40 @caution Dispatch functions must be able to cope with incoming
41 messages on an *odd* byte boundary.
43 This system doesn't have any inherent size limitations but is not
44 very efficient for large messages or when messages are sent in very
50 #include "librpc/gen_ndr/messaging.h"
51 #include "librpc/gen_ndr/ndr_messaging.h"
53 struct messaging_callback {
54 struct messaging_callback *prev, *next;
56 void (*fn)(struct messaging_context *msg, void *private_data,
58 struct server_id server_id, DATA_BLOB *data);
62 /****************************************************************************
63 A useful function for testing the message system.
64 ****************************************************************************/
66 static void ping_message(struct messaging_context *msg_ctx,
72 const char *msg = data->data ? (const char *)data->data : "none";
74 DEBUG(1,("INFO: Received PING message from PID %s [%s]\n",
75 procid_str_static(&src), msg));
76 messaging_send(msg_ctx, src, MSG_PONG, data);
79 /****************************************************************************
80 Register/replace a dispatch function for a particular message type.
81 JRA changed Dec 13 2006. Only one message handler now permitted per type.
82 *NOTE*: Dispatch functions must be able to cope with incoming
83 messages on an *odd* byte boundary.
84 ****************************************************************************/
87 struct messaging_context *msg_ctx;
95 /****************************************************************************
96 Send one of the messages for the broadcast.
97 ****************************************************************************/
99 static int traverse_fn(struct db_record *rec,
100 const struct connections_key *ckey,
101 const struct connections_data *crec,
104 struct msg_all *msg_all = (struct msg_all *)state;
107 if (crec->cnum != -1)
110 /* Don't send if the receiver hasn't registered an interest. */
112 if(!(crec->bcast_msg_flags & msg_all->msg_flag))
115 /* If the msg send fails because the pid was not found (i.e. smbd died),
116 * the msg has already been deleted from the messages.tdb.*/
118 status = messaging_send_buf(msg_all->msg_ctx,
119 crec->pid, msg_all->msg_type,
120 (uint8 *)msg_all->buf, msg_all->len);
122 if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
124 /* If the pid was not found delete the entry from connections.tdb */
126 DEBUG(2,("pid %s doesn't exist - deleting connections %d [%s]\n",
127 procid_str_static(&crec->pid), crec->cnum,
130 rec->delete_rec(rec);
137 * Send a message to all smbd processes.
139 * It isn't very efficient, but should be OK for the sorts of
140 * applications that use it. When we need efficient broadcast we can add
143 * @param n_sent Set to the number of messages sent. This should be
144 * equal to the number of processes, but be careful for races.
146 * @retval True for success.
148 BOOL message_send_all(struct messaging_context *msg_ctx,
150 const void *buf, size_t len,
153 struct msg_all msg_all;
155 msg_all.msg_type = msg_type;
157 msg_all.msg_flag = FLAG_MSG_GENERAL;
158 else if (msg_type > 1000 && msg_type < 2000)
159 msg_all.msg_flag = FLAG_MSG_NMBD;
160 else if (msg_type > 2000 && msg_type < 2100)
161 msg_all.msg_flag = FLAG_MSG_PRINT_NOTIFY;
162 else if (msg_type > 2100 && msg_type < 3000)
163 msg_all.msg_flag = FLAG_MSG_PRINT_GENERAL;
164 else if (msg_type > 3000 && msg_type < 4000)
165 msg_all.msg_flag = FLAG_MSG_SMBD;
172 msg_all.msg_ctx = msg_ctx;
174 connections_forall(traverse_fn, &msg_all);
176 *n_sent = msg_all.n_sent;
180 struct event_context *messaging_event_context(struct messaging_context *msg_ctx)
182 return msg_ctx->event_ctx;
185 struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx,
186 struct server_id server_id,
187 struct event_context *ev)
189 struct messaging_context *ctx;
192 if (!(ctx = TALLOC_ZERO_P(mem_ctx, struct messaging_context))) {
199 status = messaging_tdb_init(ctx, ctx, &ctx->local);
201 if (!NT_STATUS_IS_OK(status)) {
202 DEBUG(0, ("messaging_tdb_init failed: %s\n",
208 messaging_register(ctx, NULL, MSG_PING, ping_message);
210 /* Register some debugging related messages */
212 register_msg_pool_usage(ctx);
213 register_dmalloc_msgs(ctx);
214 debug_register_msgs(ctx);
220 * Register a dispatch function for a particular message type. Allow multiple
223 NTSTATUS messaging_register(struct messaging_context *msg_ctx,
226 void (*fn)(struct messaging_context *msg,
229 struct server_id server_id,
232 struct messaging_callback *cb;
235 * Only one callback per type
238 for (cb = msg_ctx->callbacks; cb != NULL; cb = cb->next) {
239 if (cb->msg_type == msg_type) {
241 cb->private_data = private_data;
246 if (!(cb = talloc(msg_ctx, struct messaging_callback))) {
247 return NT_STATUS_NO_MEMORY;
250 cb->msg_type = msg_type;
252 cb->private_data = private_data;
254 DLIST_ADD(msg_ctx->callbacks, cb);
259 De-register the function for a particular message type.
261 void messaging_deregister(struct messaging_context *ctx, uint32_t msg_type,
264 struct messaging_callback *cb, *next;
266 for (cb = ctx->callbacks; cb; cb = next) {
268 if ((cb->msg_type == msg_type)
269 && (cb->private_data == private_data)) {
270 DLIST_REMOVE(ctx->callbacks, cb);
277 Send a message to a particular server
279 NTSTATUS messaging_send(struct messaging_context *msg_ctx,
280 struct server_id server, uint32_t msg_type,
281 const DATA_BLOB *data)
283 return msg_ctx->local->send_fn(msg_ctx, server, msg_type, data,
287 NTSTATUS messaging_send_buf(struct messaging_context *msg_ctx,
288 struct server_id server, uint32_t msg_type,
289 const uint8 *buf, size_t len)
291 DATA_BLOB blob = data_blob_const(buf, len);
292 return messaging_send(msg_ctx, server, msg_type, &blob);
296 Dispatch one messsaging_rec
298 void messaging_dispatch_rec(struct messaging_context *msg_ctx,
299 struct messaging_rec *rec)
301 struct messaging_callback *cb, *next;
303 for (cb = msg_ctx->callbacks; cb != NULL; cb = next) {
305 if (cb->msg_type == rec->msg_type) {
306 cb->fn(msg_ctx, cb->private_data, rec->msg_type,
307 rec->src, &rec->buf);