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 3 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, see <http://www.gnu.org/licenses/>.
24 @defgroup messages Internal messaging framework
28 @brief Module for internal messaging between Samba daemons.
30 The idea is that if a part of Samba wants to do communication with
31 another Samba process then it will do a message_register() of a
32 dispatch function, and use message_send_pid() to send messages to
35 The dispatch function is given the pid of the sender, and it can
36 use that to reply by message_send_pid(). See ping_message() for a
39 @caution Dispatch functions must be able to cope with incoming
40 messages on an *odd* byte boundary.
42 This system doesn't have any inherent size limitations but is not
43 very efficient for large messages or when messages are sent in very
49 #include "dbwrap/dbwrap.h"
52 #include "lib/util/tevent_unix.h"
53 #include "lib/background.h"
55 struct messaging_callback {
56 struct messaging_callback *prev, *next;
58 void (*fn)(struct messaging_context *msg, void *private_data,
60 struct server_id server_id, DATA_BLOB *data);
64 /****************************************************************************
65 A useful function for testing the message system.
66 ****************************************************************************/
68 static void ping_message(struct messaging_context *msg_ctx,
74 const char *msg = "none";
77 if (data->data != NULL) {
78 free_me = talloc_strndup(talloc_tos(), (char *)data->data,
82 DEBUG(1,("INFO: Received PING message from PID %s [%s]\n",
83 procid_str_static(&src), msg));
85 messaging_send(msg_ctx, src, MSG_PONG, data);
88 /****************************************************************************
89 Register/replace a dispatch function for a particular message type.
90 JRA changed Dec 13 2006. Only one message handler now permitted per type.
91 *NOTE*: Dispatch functions must be able to cope with incoming
92 messages on an *odd* byte boundary.
93 ****************************************************************************/
96 struct messaging_context *msg_ctx;
104 /****************************************************************************
105 Send one of the messages for the broadcast.
106 ****************************************************************************/
108 static int traverse_fn(struct db_record *rec, const struct server_id *id,
109 uint32_t msg_flags, void *state)
111 struct msg_all *msg_all = (struct msg_all *)state;
114 /* Don't send if the receiver hasn't registered an interest. */
116 if((msg_flags & msg_all->msg_flag) == 0) {
120 /* If the msg send fails because the pid was not found (i.e. smbd died),
121 * the msg has already been deleted from the messages.tdb.*/
123 status = messaging_send_buf(msg_all->msg_ctx, *id, msg_all->msg_type,
124 (const uint8_t *)msg_all->buf, msg_all->len);
126 if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
129 * If the pid was not found delete the entry from
133 DEBUG(2, ("pid %s doesn't exist\n", procid_str_static(id)));
135 dbwrap_record_delete(rec);
142 * Send a message to all smbd processes.
144 * It isn't very efficient, but should be OK for the sorts of
145 * applications that use it. When we need efficient broadcast we can add
148 * @param n_sent Set to the number of messages sent. This should be
149 * equal to the number of processes, but be careful for races.
151 * @retval True for success.
153 bool message_send_all(struct messaging_context *msg_ctx,
155 const void *buf, size_t len,
158 struct msg_all msg_all;
160 msg_all.msg_type = msg_type;
161 if (msg_type < 0x100) {
162 msg_all.msg_flag = FLAG_MSG_GENERAL;
163 } else if (msg_type > 0x100 && msg_type < 0x200) {
164 msg_all.msg_flag = FLAG_MSG_NMBD;
165 } else if (msg_type > 0x200 && msg_type < 0x300) {
166 msg_all.msg_flag = FLAG_MSG_PRINT_GENERAL;
167 } else if (msg_type > 0x300 && msg_type < 0x400) {
168 msg_all.msg_flag = FLAG_MSG_SMBD;
169 } else if (msg_type > 0x400 && msg_type < 0x600) {
170 msg_all.msg_flag = FLAG_MSG_WINBIND;
171 } else if (msg_type > 4000 && msg_type < 5000) {
172 msg_all.msg_flag = FLAG_MSG_DBWRAP;
180 msg_all.msg_ctx = msg_ctx;
182 serverid_traverse(traverse_fn, &msg_all);
184 *n_sent = msg_all.n_sent;
188 struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx,
189 struct tevent_context *ev)
191 struct messaging_context *ctx;
194 if (!(ctx = talloc_zero(mem_ctx, struct messaging_context))) {
198 ctx->id = procid_self();
201 status = messaging_dgm_init(ctx, ctx, &ctx->local);
203 if (!NT_STATUS_IS_OK(status)) {
204 DEBUG(2, ("messaging_dgm_init failed: %s\n",
210 if (lp_clustering()) {
211 status = messaging_ctdbd_init(ctx, ctx, &ctx->remote);
213 if (!NT_STATUS_IS_OK(status)) {
214 DEBUG(2, ("messaging_ctdbd_init failed: %s\n",
220 ctx->id.vnn = get_my_vnn();
222 messaging_register(ctx, NULL, MSG_PING, ping_message);
224 /* Register some debugging related messages */
226 register_msg_pool_usage(ctx);
227 register_dmalloc_msgs(ctx);
228 debug_register_msgs(ctx);
233 struct server_id messaging_server_id(const struct messaging_context *msg_ctx)
239 * re-init after a fork
241 NTSTATUS messaging_reinit(struct messaging_context *msg_ctx)
245 TALLOC_FREE(msg_ctx->local);
247 msg_ctx->id = procid_self();
249 status = messaging_dgm_init(msg_ctx, msg_ctx, &msg_ctx->local);
250 if (!NT_STATUS_IS_OK(status)) {
251 DEBUG(0, ("messaging_dgm_init failed: %s\n",
256 TALLOC_FREE(msg_ctx->remote);
258 if (lp_clustering()) {
259 status = messaging_ctdbd_init(msg_ctx, msg_ctx,
262 if (!NT_STATUS_IS_OK(status)) {
263 DEBUG(1, ("messaging_ctdbd_init failed: %s\n",
274 * Register a dispatch function for a particular message type. Allow multiple
277 NTSTATUS messaging_register(struct messaging_context *msg_ctx,
280 void (*fn)(struct messaging_context *msg,
283 struct server_id server_id,
286 struct messaging_callback *cb;
288 DEBUG(5, ("Registering messaging pointer for type %u - "
290 (unsigned)msg_type, private_data));
293 * Only one callback per type
296 for (cb = msg_ctx->callbacks; cb != NULL; cb = cb->next) {
297 /* we allow a second registration of the same message
298 type if it has a different private pointer. This is
299 needed in, for example, the internal notify code,
300 which creates a new notify context for each tree
301 connect, and expects to receive messages to each of
303 if (cb->msg_type == msg_type && private_data == cb->private_data) {
304 DEBUG(5,("Overriding messaging pointer for type %u - private_data=%p\n",
305 (unsigned)msg_type, private_data));
307 cb->private_data = private_data;
312 if (!(cb = talloc(msg_ctx, struct messaging_callback))) {
313 return NT_STATUS_NO_MEMORY;
316 cb->msg_type = msg_type;
318 cb->private_data = private_data;
320 DLIST_ADD(msg_ctx->callbacks, cb);
325 De-register the function for a particular message type.
327 void messaging_deregister(struct messaging_context *ctx, uint32_t msg_type,
330 struct messaging_callback *cb, *next;
332 for (cb = ctx->callbacks; cb; cb = next) {
334 if ((cb->msg_type == msg_type)
335 && (cb->private_data == private_data)) {
336 DEBUG(5,("Deregistering messaging pointer for type %u - private_data=%p\n",
337 (unsigned)msg_type, private_data));
338 DLIST_REMOVE(ctx->callbacks, cb);
344 static bool messaging_is_self_send(const struct messaging_context *msg_ctx,
345 const struct server_id *dst)
347 return ((msg_ctx->id.vnn == dst->vnn) &&
348 (msg_ctx->id.pid == dst->pid));
352 Send a message to a particular server
354 NTSTATUS messaging_send(struct messaging_context *msg_ctx,
355 struct server_id server, uint32_t msg_type,
356 const DATA_BLOB *data)
360 iov.iov_base = data->data;
361 iov.iov_len = data->length;
363 return messaging_send_iov(msg_ctx, server, msg_type, &iov, 1);
366 NTSTATUS messaging_send_buf(struct messaging_context *msg_ctx,
367 struct server_id server, uint32_t msg_type,
368 const uint8_t *buf, size_t len)
370 DATA_BLOB blob = data_blob_const(buf, len);
371 return messaging_send(msg_ctx, server, msg_type, &blob);
374 NTSTATUS messaging_send_iov(struct messaging_context *msg_ctx,
375 struct server_id server, uint32_t msg_type,
376 const struct iovec *iov, int iovlen)
378 if (server_id_is_disconnected(&server)) {
379 return NT_STATUS_INVALID_PARAMETER_MIX;
382 if (!procid_is_local(&server)) {
383 return msg_ctx->remote->send_fn(msg_ctx, server,
384 msg_type, iov, iovlen,
388 if (messaging_is_self_send(msg_ctx, &server)) {
389 struct messaging_rec rec;
393 buf = iov_buf(talloc_tos(), iov, iovlen);
395 return NT_STATUS_NO_MEMORY;
398 data = data_blob_const(buf, talloc_get_size(buf));
400 rec.msg_version = MESSAGE_VERSION;
401 rec.msg_type = msg_type & MSG_TYPE_MASK;
403 rec.src = msg_ctx->id;
405 messaging_dispatch_rec(msg_ctx, &rec);
410 return msg_ctx->local->send_fn(msg_ctx, server, msg_type, iov, iovlen,
414 static struct messaging_rec *messaging_rec_dup(TALLOC_CTX *mem_ctx,
415 struct messaging_rec *rec)
417 struct messaging_rec *result;
419 result = talloc_pooled_object(mem_ctx, struct messaging_rec,
421 if (result == NULL) {
426 /* Doesn't fail, see talloc_pooled_object */
428 result->buf.data = talloc_memdup(result, rec->buf.data,
433 struct messaging_filtered_read_state {
434 struct tevent_context *ev;
435 struct messaging_context *msg_ctx;
438 bool (*filter)(struct messaging_rec *rec, void *private_data);
441 struct messaging_rec *rec;
444 static void messaging_filtered_read_cleanup(struct tevent_req *req,
445 enum tevent_req_state req_state);
447 struct tevent_req *messaging_filtered_read_send(
448 TALLOC_CTX *mem_ctx, struct tevent_context *ev,
449 struct messaging_context *msg_ctx,
450 bool (*filter)(struct messaging_rec *rec, void *private_data),
453 struct tevent_req *req;
454 struct messaging_filtered_read_state *state;
455 size_t new_waiters_len;
457 req = tevent_req_create(mem_ctx, &state,
458 struct messaging_filtered_read_state);
463 state->msg_ctx = msg_ctx;
464 state->filter = filter;
465 state->private_data = private_data;
468 * We have to defer the callback here, as we might be called from
469 * within a different tevent_context than state->ev
471 tevent_req_defer_callback(req, state->ev);
473 state->tevent_handle = messaging_dgm_register_tevent_context(
475 if (tevent_req_nomem(state, req)) {
476 return tevent_req_post(req, ev);
480 * We add ourselves to the "new_waiters" array, not the "waiters"
481 * array. If we are called from within messaging_read_done,
482 * messaging_dispatch_rec will be in an active for-loop on
483 * "waiters". We must be careful not to mess with this array, because
484 * it could mean that a single event is being delivered twice.
487 new_waiters_len = talloc_array_length(msg_ctx->new_waiters);
489 if (new_waiters_len == msg_ctx->num_new_waiters) {
490 struct tevent_req **tmp;
492 tmp = talloc_realloc(msg_ctx, msg_ctx->new_waiters,
493 struct tevent_req *, new_waiters_len+1);
494 if (tevent_req_nomem(tmp, req)) {
495 return tevent_req_post(req, ev);
497 msg_ctx->new_waiters = tmp;
500 msg_ctx->new_waiters[msg_ctx->num_new_waiters] = req;
501 msg_ctx->num_new_waiters += 1;
502 tevent_req_set_cleanup_fn(req, messaging_filtered_read_cleanup);
507 static void messaging_filtered_read_cleanup(struct tevent_req *req,
508 enum tevent_req_state req_state)
510 struct messaging_filtered_read_state *state = tevent_req_data(
511 req, struct messaging_filtered_read_state);
512 struct messaging_context *msg_ctx = state->msg_ctx;
515 tevent_req_set_cleanup_fn(req, NULL);
517 TALLOC_FREE(state->tevent_handle);
520 * Just set the [new_]waiters entry to NULL, be careful not to mess
521 * with the other "waiters" array contents. We are often called from
522 * within "messaging_dispatch_rec", which loops over
523 * "waiters". Messing with the "waiters" array will mess up that
527 for (i=0; i<msg_ctx->num_waiters; i++) {
528 if (msg_ctx->waiters[i] == req) {
529 msg_ctx->waiters[i] = NULL;
534 for (i=0; i<msg_ctx->num_new_waiters; i++) {
535 if (msg_ctx->new_waiters[i] == req) {
536 msg_ctx->new_waiters[i] = NULL;
542 static void messaging_filtered_read_done(struct tevent_req *req,
543 struct messaging_rec *rec)
545 struct messaging_filtered_read_state *state = tevent_req_data(
546 req, struct messaging_filtered_read_state);
548 state->rec = messaging_rec_dup(state, rec);
549 if (tevent_req_nomem(state->rec, req)) {
552 tevent_req_done(req);
555 int messaging_filtered_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
556 struct messaging_rec **presult)
558 struct messaging_filtered_read_state *state = tevent_req_data(
559 req, struct messaging_filtered_read_state);
562 if (tevent_req_is_unix_error(req, &err)) {
563 tevent_req_received(req);
566 *presult = talloc_move(mem_ctx, &state->rec);
570 struct messaging_read_state {
572 struct messaging_rec *rec;
575 static bool messaging_read_filter(struct messaging_rec *rec,
577 static void messaging_read_done(struct tevent_req *subreq);
579 struct tevent_req *messaging_read_send(TALLOC_CTX *mem_ctx,
580 struct tevent_context *ev,
581 struct messaging_context *msg,
584 struct tevent_req *req, *subreq;
585 struct messaging_read_state *state;
587 req = tevent_req_create(mem_ctx, &state,
588 struct messaging_read_state);
592 state->msg_type = msg_type;
594 subreq = messaging_filtered_read_send(state, ev, msg,
595 messaging_read_filter, state);
596 if (tevent_req_nomem(subreq, req)) {
597 return tevent_req_post(req, ev);
599 tevent_req_set_callback(subreq, messaging_read_done, req);
603 static bool messaging_read_filter(struct messaging_rec *rec,
606 struct messaging_read_state *state = talloc_get_type_abort(
607 private_data, struct messaging_read_state);
609 return rec->msg_type == state->msg_type;
612 static void messaging_read_done(struct tevent_req *subreq)
614 struct tevent_req *req = tevent_req_callback_data(
615 subreq, struct tevent_req);
616 struct messaging_read_state *state = tevent_req_data(
617 req, struct messaging_read_state);
620 ret = messaging_filtered_read_recv(subreq, state, &state->rec);
622 if (tevent_req_error(req, ret)) {
625 tevent_req_done(req);
628 int messaging_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
629 struct messaging_rec **presult)
631 struct messaging_read_state *state = tevent_req_data(
632 req, struct messaging_read_state);
635 if (tevent_req_is_unix_error(req, &err)) {
638 if (presult != NULL) {
639 *presult = talloc_move(mem_ctx, &state->rec);
644 static bool messaging_append_new_waiters(struct messaging_context *msg_ctx)
646 if (msg_ctx->num_new_waiters == 0) {
650 if (talloc_array_length(msg_ctx->waiters) <
651 (msg_ctx->num_waiters + msg_ctx->num_new_waiters)) {
652 struct tevent_req **tmp;
653 tmp = talloc_realloc(
654 msg_ctx, msg_ctx->waiters, struct tevent_req *,
655 msg_ctx->num_waiters + msg_ctx->num_new_waiters);
657 DEBUG(1, ("%s: talloc failed\n", __func__));
660 msg_ctx->waiters = tmp;
663 memcpy(&msg_ctx->waiters[msg_ctx->num_waiters], msg_ctx->new_waiters,
664 sizeof(struct tevent_req *) * msg_ctx->num_new_waiters);
666 msg_ctx->num_waiters += msg_ctx->num_new_waiters;
667 msg_ctx->num_new_waiters = 0;
672 struct messaging_defer_callback_state {
673 struct messaging_context *msg_ctx;
674 struct messaging_rec *rec;
675 void (*fn)(struct messaging_context *msg, void *private_data,
676 uint32_t msg_type, struct server_id server_id,
681 static void messaging_defer_callback_trigger(struct tevent_context *ev,
682 struct tevent_immediate *im,
685 static void messaging_defer_callback(
686 struct messaging_context *msg_ctx, struct messaging_rec *rec,
687 void (*fn)(struct messaging_context *msg, void *private_data,
688 uint32_t msg_type, struct server_id server_id,
692 struct messaging_defer_callback_state *state;
693 struct tevent_immediate *im;
695 state = talloc(msg_ctx, struct messaging_defer_callback_state);
697 DEBUG(1, ("talloc failed\n"));
700 state->msg_ctx = msg_ctx;
702 state->private_data = private_data;
704 state->rec = messaging_rec_dup(state, rec);
705 if (state->rec == NULL) {
706 DEBUG(1, ("talloc failed\n"));
711 im = tevent_create_immediate(state);
713 DEBUG(1, ("tevent_create_immediate failed\n"));
717 tevent_schedule_immediate(im, msg_ctx->event_ctx,
718 messaging_defer_callback_trigger, state);
721 static void messaging_defer_callback_trigger(struct tevent_context *ev,
722 struct tevent_immediate *im,
725 struct messaging_defer_callback_state *state = talloc_get_type_abort(
726 private_data, struct messaging_defer_callback_state);
727 struct messaging_rec *rec = state->rec;
729 state->fn(state->msg_ctx, state->private_data, rec->msg_type, rec->src,
735 Dispatch one messaging_rec
737 void messaging_dispatch_rec(struct messaging_context *msg_ctx,
738 struct messaging_rec *rec)
740 struct messaging_callback *cb, *next;
743 for (cb = msg_ctx->callbacks; cb != NULL; cb = next) {
745 if (cb->msg_type != rec->msg_type) {
749 if (messaging_is_self_send(msg_ctx, &rec->dest)) {
751 * This is a self-send. We are called here from
752 * messaging_send(), and we don't want to directly
753 * recurse into the callback but go via a
756 messaging_defer_callback(msg_ctx, rec, cb->fn,
760 * This comes from a different process. we are called
761 * from the event loop, so we should call back
764 cb->fn(msg_ctx, cb->private_data, rec->msg_type,
765 rec->src, &rec->buf);
768 * we continue looking for matching messages after finding
769 * one. This matters for subsystems like the internal notify
770 * code which register more than one handler for the same
775 if (!messaging_append_new_waiters(msg_ctx)) {
780 while (i < msg_ctx->num_waiters) {
781 struct tevent_req *req;
782 struct messaging_filtered_read_state *state;
784 req = msg_ctx->waiters[i];
787 * This got cleaned up. In the meantime,
788 * move everything down one. We need
789 * to keep the order of waiters, as
790 * other code may depend on this.
792 if (i < msg_ctx->num_waiters - 1) {
793 memmove(&msg_ctx->waiters[i],
794 &msg_ctx->waiters[i+1],
795 sizeof(struct tevent_req *) *
796 (msg_ctx->num_waiters - i - 1));
798 msg_ctx->num_waiters -= 1;
802 state = tevent_req_data(
803 req, struct messaging_filtered_read_state);
804 if (state->filter(rec, state->private_data)) {
805 messaging_filtered_read_done(req, rec);
812 static int mess_parent_dgm_cleanup(void *private_data);
813 static void mess_parent_dgm_cleanup_done(struct tevent_req *req);
815 bool messaging_parent_dgm_cleanup_init(struct messaging_context *msg)
817 struct tevent_req *req;
819 req = background_job_send(
820 msg, msg->event_ctx, msg, NULL, 0,
821 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
823 mess_parent_dgm_cleanup, msg);
827 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
831 static int mess_parent_dgm_cleanup(void *private_data)
833 struct messaging_context *msg_ctx = talloc_get_type_abort(
834 private_data, struct messaging_context);
837 status = messaging_dgm_wipe(msg_ctx);
838 DEBUG(10, ("messaging_dgm_wipe returned %s\n", nt_errstr(status)));
839 return lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
843 static void mess_parent_dgm_cleanup_done(struct tevent_req *req)
845 struct messaging_context *msg = tevent_req_callback_data(
846 req, struct messaging_context);
849 status = background_job_recv(req);
851 DEBUG(1, ("messaging dgm cleanup job ended with %s\n",
854 req = background_job_send(
855 msg, msg->event_ctx, msg, NULL, 0,
856 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
858 mess_parent_dgm_cleanup, msg);
860 DEBUG(1, ("background_job_send failed\n"));
862 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);