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)
358 if (server_id_is_disconnected(&server)) {
359 return NT_STATUS_INVALID_PARAMETER_MIX;
362 if (!procid_is_local(&server)) {
363 return msg_ctx->remote->send_fn(msg_ctx, server,
368 if (messaging_is_self_send(msg_ctx, &server)) {
369 struct messaging_rec rec;
370 rec.msg_version = MESSAGE_VERSION;
371 rec.msg_type = msg_type & MSG_TYPE_MASK;
373 rec.src = msg_ctx->id;
375 messaging_dispatch_rec(msg_ctx, &rec);
379 return msg_ctx->local->send_fn(msg_ctx, server, msg_type, data,
383 NTSTATUS messaging_send_buf(struct messaging_context *msg_ctx,
384 struct server_id server, uint32_t msg_type,
385 const uint8_t *buf, size_t len)
387 DATA_BLOB blob = data_blob_const(buf, len);
388 return messaging_send(msg_ctx, server, msg_type, &blob);
391 NTSTATUS messaging_send_iov(struct messaging_context *msg_ctx,
392 struct server_id server, uint32_t msg_type,
393 const struct iovec *iov, int iovlen)
398 buf = iov_buf(talloc_tos(), iov, iovlen);
400 return NT_STATUS_NO_MEMORY;
403 status = messaging_send_buf(msg_ctx, server, msg_type,
404 buf, talloc_get_size(buf));
410 static struct messaging_rec *messaging_rec_dup(TALLOC_CTX *mem_ctx,
411 struct messaging_rec *rec)
413 struct messaging_rec *result;
415 result = talloc_pooled_object(mem_ctx, struct messaging_rec,
417 if (result == NULL) {
422 /* Doesn't fail, see talloc_pooled_object */
424 result->buf.data = talloc_memdup(result, rec->buf.data,
429 struct messaging_filtered_read_state {
430 struct tevent_context *ev;
431 struct messaging_context *msg_ctx;
434 bool (*filter)(struct messaging_rec *rec, void *private_data);
437 struct messaging_rec *rec;
440 static void messaging_filtered_read_cleanup(struct tevent_req *req,
441 enum tevent_req_state req_state);
443 struct tevent_req *messaging_filtered_read_send(
444 TALLOC_CTX *mem_ctx, struct tevent_context *ev,
445 struct messaging_context *msg_ctx,
446 bool (*filter)(struct messaging_rec *rec, void *private_data),
449 struct tevent_req *req;
450 struct messaging_filtered_read_state *state;
451 size_t new_waiters_len;
453 req = tevent_req_create(mem_ctx, &state,
454 struct messaging_filtered_read_state);
459 state->msg_ctx = msg_ctx;
460 state->filter = filter;
461 state->private_data = private_data;
464 * We have to defer the callback here, as we might be called from
465 * within a different tevent_context than state->ev
467 tevent_req_defer_callback(req, state->ev);
469 state->tevent_handle = messaging_dgm_register_tevent_context(
471 if (tevent_req_nomem(state, req)) {
472 return tevent_req_post(req, ev);
476 * We add ourselves to the "new_waiters" array, not the "waiters"
477 * array. If we are called from within messaging_read_done,
478 * messaging_dispatch_rec will be in an active for-loop on
479 * "waiters". We must be careful not to mess with this array, because
480 * it could mean that a single event is being delivered twice.
483 new_waiters_len = talloc_array_length(msg_ctx->new_waiters);
485 if (new_waiters_len == msg_ctx->num_new_waiters) {
486 struct tevent_req **tmp;
488 tmp = talloc_realloc(msg_ctx, msg_ctx->new_waiters,
489 struct tevent_req *, new_waiters_len+1);
490 if (tevent_req_nomem(tmp, req)) {
491 return tevent_req_post(req, ev);
493 msg_ctx->new_waiters = tmp;
496 msg_ctx->new_waiters[msg_ctx->num_new_waiters] = req;
497 msg_ctx->num_new_waiters += 1;
498 tevent_req_set_cleanup_fn(req, messaging_filtered_read_cleanup);
503 static void messaging_filtered_read_cleanup(struct tevent_req *req,
504 enum tevent_req_state req_state)
506 struct messaging_filtered_read_state *state = tevent_req_data(
507 req, struct messaging_filtered_read_state);
508 struct messaging_context *msg_ctx = state->msg_ctx;
511 tevent_req_set_cleanup_fn(req, NULL);
513 TALLOC_FREE(state->tevent_handle);
516 * Just set the [new_]waiters entry to NULL, be careful not to mess
517 * with the other "waiters" array contents. We are often called from
518 * within "messaging_dispatch_rec", which loops over
519 * "waiters". Messing with the "waiters" array will mess up that
523 for (i=0; i<msg_ctx->num_waiters; i++) {
524 if (msg_ctx->waiters[i] == req) {
525 msg_ctx->waiters[i] = NULL;
530 for (i=0; i<msg_ctx->num_new_waiters; i++) {
531 if (msg_ctx->new_waiters[i] == req) {
532 msg_ctx->new_waiters[i] = NULL;
538 static void messaging_filtered_read_done(struct tevent_req *req,
539 struct messaging_rec *rec)
541 struct messaging_filtered_read_state *state = tevent_req_data(
542 req, struct messaging_filtered_read_state);
544 state->rec = messaging_rec_dup(state, rec);
545 if (tevent_req_nomem(state->rec, req)) {
548 tevent_req_done(req);
551 int messaging_filtered_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
552 struct messaging_rec **presult)
554 struct messaging_filtered_read_state *state = tevent_req_data(
555 req, struct messaging_filtered_read_state);
558 if (tevent_req_is_unix_error(req, &err)) {
559 tevent_req_received(req);
562 *presult = talloc_move(mem_ctx, &state->rec);
566 struct messaging_read_state {
568 struct messaging_rec *rec;
571 static bool messaging_read_filter(struct messaging_rec *rec,
573 static void messaging_read_done(struct tevent_req *subreq);
575 struct tevent_req *messaging_read_send(TALLOC_CTX *mem_ctx,
576 struct tevent_context *ev,
577 struct messaging_context *msg,
580 struct tevent_req *req, *subreq;
581 struct messaging_read_state *state;
583 req = tevent_req_create(mem_ctx, &state,
584 struct messaging_read_state);
588 state->msg_type = msg_type;
590 subreq = messaging_filtered_read_send(state, ev, msg,
591 messaging_read_filter, state);
592 if (tevent_req_nomem(subreq, req)) {
593 return tevent_req_post(req, ev);
595 tevent_req_set_callback(subreq, messaging_read_done, req);
599 static bool messaging_read_filter(struct messaging_rec *rec,
602 struct messaging_read_state *state = talloc_get_type_abort(
603 private_data, struct messaging_read_state);
605 return rec->msg_type == state->msg_type;
608 static void messaging_read_done(struct tevent_req *subreq)
610 struct tevent_req *req = tevent_req_callback_data(
611 subreq, struct tevent_req);
612 struct messaging_read_state *state = tevent_req_data(
613 req, struct messaging_read_state);
616 ret = messaging_filtered_read_recv(subreq, state, &state->rec);
618 if (tevent_req_error(req, ret)) {
621 tevent_req_done(req);
624 int messaging_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
625 struct messaging_rec **presult)
627 struct messaging_read_state *state = tevent_req_data(
628 req, struct messaging_read_state);
631 if (tevent_req_is_unix_error(req, &err)) {
634 if (presult != NULL) {
635 *presult = talloc_move(mem_ctx, &state->rec);
640 static bool messaging_append_new_waiters(struct messaging_context *msg_ctx)
642 if (msg_ctx->num_new_waiters == 0) {
646 if (talloc_array_length(msg_ctx->waiters) <
647 (msg_ctx->num_waiters + msg_ctx->num_new_waiters)) {
648 struct tevent_req **tmp;
649 tmp = talloc_realloc(
650 msg_ctx, msg_ctx->waiters, struct tevent_req *,
651 msg_ctx->num_waiters + msg_ctx->num_new_waiters);
653 DEBUG(1, ("%s: talloc failed\n", __func__));
656 msg_ctx->waiters = tmp;
659 memcpy(&msg_ctx->waiters[msg_ctx->num_waiters], msg_ctx->new_waiters,
660 sizeof(struct tevent_req *) * msg_ctx->num_new_waiters);
662 msg_ctx->num_waiters += msg_ctx->num_new_waiters;
663 msg_ctx->num_new_waiters = 0;
668 struct messaging_defer_callback_state {
669 struct messaging_context *msg_ctx;
670 struct messaging_rec *rec;
671 void (*fn)(struct messaging_context *msg, void *private_data,
672 uint32_t msg_type, struct server_id server_id,
677 static void messaging_defer_callback_trigger(struct tevent_context *ev,
678 struct tevent_immediate *im,
681 static void messaging_defer_callback(
682 struct messaging_context *msg_ctx, struct messaging_rec *rec,
683 void (*fn)(struct messaging_context *msg, void *private_data,
684 uint32_t msg_type, struct server_id server_id,
688 struct messaging_defer_callback_state *state;
689 struct tevent_immediate *im;
691 state = talloc(msg_ctx, struct messaging_defer_callback_state);
693 DEBUG(1, ("talloc failed\n"));
696 state->msg_ctx = msg_ctx;
698 state->private_data = private_data;
700 state->rec = messaging_rec_dup(state, rec);
701 if (state->rec == NULL) {
702 DEBUG(1, ("talloc failed\n"));
707 im = tevent_create_immediate(state);
709 DEBUG(1, ("tevent_create_immediate failed\n"));
713 tevent_schedule_immediate(im, msg_ctx->event_ctx,
714 messaging_defer_callback_trigger, state);
717 static void messaging_defer_callback_trigger(struct tevent_context *ev,
718 struct tevent_immediate *im,
721 struct messaging_defer_callback_state *state = talloc_get_type_abort(
722 private_data, struct messaging_defer_callback_state);
723 struct messaging_rec *rec = state->rec;
725 state->fn(state->msg_ctx, state->private_data, rec->msg_type, rec->src,
731 Dispatch one messaging_rec
733 void messaging_dispatch_rec(struct messaging_context *msg_ctx,
734 struct messaging_rec *rec)
736 struct messaging_callback *cb, *next;
739 for (cb = msg_ctx->callbacks; cb != NULL; cb = next) {
741 if (cb->msg_type != rec->msg_type) {
745 if (messaging_is_self_send(msg_ctx, &rec->dest)) {
747 * This is a self-send. We are called here from
748 * messaging_send(), and we don't want to directly
749 * recurse into the callback but go via a
752 messaging_defer_callback(msg_ctx, rec, cb->fn,
756 * This comes from a different process. we are called
757 * from the event loop, so we should call back
760 cb->fn(msg_ctx, cb->private_data, rec->msg_type,
761 rec->src, &rec->buf);
764 * we continue looking for matching messages after finding
765 * one. This matters for subsystems like the internal notify
766 * code which register more than one handler for the same
771 if (!messaging_append_new_waiters(msg_ctx)) {
776 while (i < msg_ctx->num_waiters) {
777 struct tevent_req *req;
778 struct messaging_filtered_read_state *state;
780 req = msg_ctx->waiters[i];
783 * This got cleaned up. In the meantime,
784 * move everything down one. We need
785 * to keep the order of waiters, as
786 * other code may depend on this.
788 if (i < msg_ctx->num_waiters - 1) {
789 memmove(&msg_ctx->waiters[i],
790 &msg_ctx->waiters[i+1],
791 sizeof(struct tevent_req *) *
792 (msg_ctx->num_waiters - i - 1));
794 msg_ctx->num_waiters -= 1;
798 state = tevent_req_data(
799 req, struct messaging_filtered_read_state);
800 if (state->filter(rec, state->private_data)) {
801 messaging_filtered_read_done(req, rec);
809 static int mess_parent_dgm_cleanup(void *private_data);
810 static void mess_parent_dgm_cleanup_done(struct tevent_req *req);
812 bool messaging_parent_dgm_cleanup_init(struct messaging_context *msg)
814 struct tevent_req *req;
816 req = background_job_send(
817 msg, msg->event_ctx, msg, NULL, 0,
818 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
820 mess_parent_dgm_cleanup, msg);
824 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
828 static int mess_parent_dgm_cleanup(void *private_data)
830 struct messaging_context *msg_ctx = talloc_get_type_abort(
831 private_data, struct messaging_context);
834 status = messaging_dgm_wipe(msg_ctx);
835 DEBUG(10, ("messaging_dgm_wipe returned %s\n", nt_errstr(status)));
836 return lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
840 static void mess_parent_dgm_cleanup_done(struct tevent_req *req)
842 struct messaging_context *msg = tevent_req_callback_data(
843 req, struct messaging_context);
846 status = background_job_recv(req);
848 DEBUG(1, ("messaging dgm cleanup job ended with %s\n",
851 req = background_job_send(
852 msg, msg->event_ctx, msg, NULL, 0,
853 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
855 mess_parent_dgm_cleanup, msg);
857 DEBUG(1, ("background_job_send failed\n"));
859 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);