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 struct messaging_context {
66 struct tevent_context *event_ctx;
67 struct messaging_callback *callbacks;
69 struct tevent_req **new_waiters;
70 unsigned num_new_waiters;
72 struct tevent_req **waiters;
75 struct messaging_backend *local;
76 struct messaging_backend *remote;
81 static int messaging_context_destructor(struct messaging_context *msg_ctx);
83 /****************************************************************************
84 A useful function for testing the message system.
85 ****************************************************************************/
87 static void ping_message(struct messaging_context *msg_ctx,
93 const char *msg = "none";
96 if (data->data != NULL) {
97 free_me = talloc_strndup(talloc_tos(), (char *)data->data,
101 DEBUG(1,("INFO: Received PING message from PID %s [%s]\n",
102 procid_str_static(&src), msg));
103 TALLOC_FREE(free_me);
104 messaging_send(msg_ctx, src, MSG_PONG, data);
107 /****************************************************************************
108 Register/replace a dispatch function for a particular message type.
109 JRA changed Dec 13 2006. Only one message handler now permitted per type.
110 *NOTE*: Dispatch functions must be able to cope with incoming
111 messages on an *odd* byte boundary.
112 ****************************************************************************/
115 struct messaging_context *msg_ctx;
123 /****************************************************************************
124 Send one of the messages for the broadcast.
125 ****************************************************************************/
127 static int traverse_fn(struct db_record *rec, const struct server_id *id,
128 uint32_t msg_flags, void *state)
130 struct msg_all *msg_all = (struct msg_all *)state;
133 /* Don't send if the receiver hasn't registered an interest. */
135 if((msg_flags & msg_all->msg_flag) == 0) {
139 /* If the msg send fails because the pid was not found (i.e. smbd died),
140 * the msg has already been deleted from the messages.tdb.*/
142 status = messaging_send_buf(msg_all->msg_ctx, *id, msg_all->msg_type,
143 (const uint8_t *)msg_all->buf, msg_all->len);
145 if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
148 * If the pid was not found delete the entry from
152 DEBUG(2, ("pid %s doesn't exist\n", procid_str_static(id)));
154 dbwrap_record_delete(rec);
161 * Send a message to all smbd processes.
163 * It isn't very efficient, but should be OK for the sorts of
164 * applications that use it. When we need efficient broadcast we can add
167 * @param n_sent Set to the number of messages sent. This should be
168 * equal to the number of processes, but be careful for races.
170 * @retval True for success.
172 bool message_send_all(struct messaging_context *msg_ctx,
174 const void *buf, size_t len,
177 struct msg_all msg_all;
179 msg_all.msg_type = msg_type;
180 if (msg_type < 0x100) {
181 msg_all.msg_flag = FLAG_MSG_GENERAL;
182 } else if (msg_type > 0x100 && msg_type < 0x200) {
183 msg_all.msg_flag = FLAG_MSG_NMBD;
184 } else if (msg_type > 0x200 && msg_type < 0x300) {
185 msg_all.msg_flag = FLAG_MSG_PRINT_GENERAL;
186 } else if (msg_type > 0x300 && msg_type < 0x400) {
187 msg_all.msg_flag = FLAG_MSG_SMBD;
188 } else if (msg_type > 0x400 && msg_type < 0x600) {
189 msg_all.msg_flag = FLAG_MSG_WINBIND;
190 } else if (msg_type > 4000 && msg_type < 5000) {
191 msg_all.msg_flag = FLAG_MSG_DBWRAP;
199 msg_all.msg_ctx = msg_ctx;
201 serverid_traverse(traverse_fn, &msg_all);
203 *n_sent = msg_all.n_sent;
207 struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx,
208 struct tevent_context *ev)
210 struct messaging_context *ctx;
213 static bool have_context = false;
216 DEBUG(0, ("No two messaging contexts per process\n"));
221 if (!(ctx = talloc_zero(mem_ctx, struct messaging_context))) {
225 ctx->id = procid_self();
227 ctx->have_context = &have_context;
229 ret = messaging_dgm_init(ctx, ctx, &ctx->local);
232 DEBUG(2, ("messaging_dgm_init failed: %s\n", strerror(ret)));
237 if (lp_clustering()) {
238 status = messaging_ctdbd_init(ctx, ctx, &ctx->remote);
240 if (!NT_STATUS_IS_OK(status)) {
241 DEBUG(2, ("messaging_ctdbd_init failed: %s\n",
247 ctx->id.vnn = get_my_vnn();
249 messaging_register(ctx, NULL, MSG_PING, ping_message);
251 /* Register some debugging related messages */
253 register_msg_pool_usage(ctx);
254 register_dmalloc_msgs(ctx);
255 debug_register_msgs(ctx);
258 talloc_set_destructor(ctx, messaging_context_destructor);
263 static int messaging_context_destructor(struct messaging_context *msg_ctx)
265 SMB_ASSERT(*msg_ctx->have_context);
266 *msg_ctx->have_context = false;
270 struct server_id messaging_server_id(const struct messaging_context *msg_ctx)
276 * re-init after a fork
278 NTSTATUS messaging_reinit(struct messaging_context *msg_ctx)
283 TALLOC_FREE(msg_ctx->local);
285 msg_ctx->id = procid_self();
287 ret = messaging_dgm_init(msg_ctx, msg_ctx, &msg_ctx->local);
289 DEBUG(0, ("messaging_dgm_init failed: %s\n", strerror(errno)));
290 return map_nt_error_from_unix(ret);
293 TALLOC_FREE(msg_ctx->remote);
295 if (lp_clustering()) {
296 status = messaging_ctdbd_init(msg_ctx, msg_ctx,
299 if (!NT_STATUS_IS_OK(status)) {
300 DEBUG(1, ("messaging_ctdbd_init failed: %s\n",
311 * Register a dispatch function for a particular message type. Allow multiple
314 NTSTATUS messaging_register(struct messaging_context *msg_ctx,
317 void (*fn)(struct messaging_context *msg,
320 struct server_id server_id,
323 struct messaging_callback *cb;
325 DEBUG(5, ("Registering messaging pointer for type %u - "
327 (unsigned)msg_type, private_data));
330 * Only one callback per type
333 for (cb = msg_ctx->callbacks; cb != NULL; cb = cb->next) {
334 /* we allow a second registration of the same message
335 type if it has a different private pointer. This is
336 needed in, for example, the internal notify code,
337 which creates a new notify context for each tree
338 connect, and expects to receive messages to each of
340 if (cb->msg_type == msg_type && private_data == cb->private_data) {
341 DEBUG(5,("Overriding messaging pointer for type %u - private_data=%p\n",
342 (unsigned)msg_type, private_data));
344 cb->private_data = private_data;
349 if (!(cb = talloc(msg_ctx, struct messaging_callback))) {
350 return NT_STATUS_NO_MEMORY;
353 cb->msg_type = msg_type;
355 cb->private_data = private_data;
357 DLIST_ADD(msg_ctx->callbacks, cb);
362 De-register the function for a particular message type.
364 void messaging_deregister(struct messaging_context *ctx, uint32_t msg_type,
367 struct messaging_callback *cb, *next;
369 for (cb = ctx->callbacks; cb; cb = next) {
371 if ((cb->msg_type == msg_type)
372 && (cb->private_data == private_data)) {
373 DEBUG(5,("Deregistering messaging pointer for type %u - private_data=%p\n",
374 (unsigned)msg_type, private_data));
375 DLIST_REMOVE(ctx->callbacks, cb);
381 static bool messaging_is_self_send(const struct messaging_context *msg_ctx,
382 const struct server_id *dst)
384 return ((msg_ctx->id.vnn == dst->vnn) &&
385 (msg_ctx->id.pid == dst->pid));
389 Send a message to a particular server
391 NTSTATUS messaging_send(struct messaging_context *msg_ctx,
392 struct server_id server, uint32_t msg_type,
393 const DATA_BLOB *data)
397 iov.iov_base = data->data;
398 iov.iov_len = data->length;
400 return messaging_send_iov(msg_ctx, server, msg_type, &iov, 1);
403 NTSTATUS messaging_send_buf(struct messaging_context *msg_ctx,
404 struct server_id server, uint32_t msg_type,
405 const uint8_t *buf, size_t len)
407 DATA_BLOB blob = data_blob_const(buf, len);
408 return messaging_send(msg_ctx, server, msg_type, &blob);
411 NTSTATUS messaging_send_iov(struct messaging_context *msg_ctx,
412 struct server_id server, uint32_t msg_type,
413 const struct iovec *iov, int iovlen)
417 if (server_id_is_disconnected(&server)) {
418 return NT_STATUS_INVALID_PARAMETER_MIX;
421 if (!procid_is_local(&server)) {
422 ret = msg_ctx->remote->send_fn(msg_ctx->id, server,
423 msg_type, iov, iovlen,
426 return map_nt_error_from_unix(ret);
431 if (messaging_is_self_send(msg_ctx, &server)) {
432 struct messaging_rec rec;
436 buf = iov_buf(talloc_tos(), iov, iovlen);
438 return NT_STATUS_NO_MEMORY;
441 data = data_blob_const(buf, talloc_get_size(buf));
443 rec.msg_version = MESSAGE_VERSION;
444 rec.msg_type = msg_type & MSG_TYPE_MASK;
446 rec.src = msg_ctx->id;
448 messaging_dispatch_rec(msg_ctx, &rec);
453 ret = msg_ctx->local->send_fn(msg_ctx->id, server, msg_type,
454 iov, iovlen, msg_ctx->local);
456 return map_nt_error_from_unix(ret);
461 static struct messaging_rec *messaging_rec_dup(TALLOC_CTX *mem_ctx,
462 struct messaging_rec *rec)
464 struct messaging_rec *result;
466 result = talloc_pooled_object(mem_ctx, struct messaging_rec,
468 if (result == NULL) {
473 /* Doesn't fail, see talloc_pooled_object */
475 result->buf.data = talloc_memdup(result, rec->buf.data,
480 struct messaging_filtered_read_state {
481 struct tevent_context *ev;
482 struct messaging_context *msg_ctx;
485 bool (*filter)(struct messaging_rec *rec, void *private_data);
488 struct messaging_rec *rec;
491 static void messaging_filtered_read_cleanup(struct tevent_req *req,
492 enum tevent_req_state req_state);
494 struct tevent_req *messaging_filtered_read_send(
495 TALLOC_CTX *mem_ctx, struct tevent_context *ev,
496 struct messaging_context *msg_ctx,
497 bool (*filter)(struct messaging_rec *rec, void *private_data),
500 struct tevent_req *req;
501 struct messaging_filtered_read_state *state;
502 size_t new_waiters_len;
504 req = tevent_req_create(mem_ctx, &state,
505 struct messaging_filtered_read_state);
510 state->msg_ctx = msg_ctx;
511 state->filter = filter;
512 state->private_data = private_data;
515 * We have to defer the callback here, as we might be called from
516 * within a different tevent_context than state->ev
518 tevent_req_defer_callback(req, state->ev);
520 state->tevent_handle = messaging_dgm_register_tevent_context(
522 if (tevent_req_nomem(state, req)) {
523 return tevent_req_post(req, ev);
527 * We add ourselves to the "new_waiters" array, not the "waiters"
528 * array. If we are called from within messaging_read_done,
529 * messaging_dispatch_rec will be in an active for-loop on
530 * "waiters". We must be careful not to mess with this array, because
531 * it could mean that a single event is being delivered twice.
534 new_waiters_len = talloc_array_length(msg_ctx->new_waiters);
536 if (new_waiters_len == msg_ctx->num_new_waiters) {
537 struct tevent_req **tmp;
539 tmp = talloc_realloc(msg_ctx, msg_ctx->new_waiters,
540 struct tevent_req *, new_waiters_len+1);
541 if (tevent_req_nomem(tmp, req)) {
542 return tevent_req_post(req, ev);
544 msg_ctx->new_waiters = tmp;
547 msg_ctx->new_waiters[msg_ctx->num_new_waiters] = req;
548 msg_ctx->num_new_waiters += 1;
549 tevent_req_set_cleanup_fn(req, messaging_filtered_read_cleanup);
554 static void messaging_filtered_read_cleanup(struct tevent_req *req,
555 enum tevent_req_state req_state)
557 struct messaging_filtered_read_state *state = tevent_req_data(
558 req, struct messaging_filtered_read_state);
559 struct messaging_context *msg_ctx = state->msg_ctx;
562 tevent_req_set_cleanup_fn(req, NULL);
564 TALLOC_FREE(state->tevent_handle);
567 * Just set the [new_]waiters entry to NULL, be careful not to mess
568 * with the other "waiters" array contents. We are often called from
569 * within "messaging_dispatch_rec", which loops over
570 * "waiters". Messing with the "waiters" array will mess up that
574 for (i=0; i<msg_ctx->num_waiters; i++) {
575 if (msg_ctx->waiters[i] == req) {
576 msg_ctx->waiters[i] = NULL;
581 for (i=0; i<msg_ctx->num_new_waiters; i++) {
582 if (msg_ctx->new_waiters[i] == req) {
583 msg_ctx->new_waiters[i] = NULL;
589 static void messaging_filtered_read_done(struct tevent_req *req,
590 struct messaging_rec *rec)
592 struct messaging_filtered_read_state *state = tevent_req_data(
593 req, struct messaging_filtered_read_state);
595 state->rec = messaging_rec_dup(state, rec);
596 if (tevent_req_nomem(state->rec, req)) {
599 tevent_req_done(req);
602 int messaging_filtered_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
603 struct messaging_rec **presult)
605 struct messaging_filtered_read_state *state = tevent_req_data(
606 req, struct messaging_filtered_read_state);
609 if (tevent_req_is_unix_error(req, &err)) {
610 tevent_req_received(req);
613 *presult = talloc_move(mem_ctx, &state->rec);
617 struct messaging_read_state {
619 struct messaging_rec *rec;
622 static bool messaging_read_filter(struct messaging_rec *rec,
624 static void messaging_read_done(struct tevent_req *subreq);
626 struct tevent_req *messaging_read_send(TALLOC_CTX *mem_ctx,
627 struct tevent_context *ev,
628 struct messaging_context *msg,
631 struct tevent_req *req, *subreq;
632 struct messaging_read_state *state;
634 req = tevent_req_create(mem_ctx, &state,
635 struct messaging_read_state);
639 state->msg_type = msg_type;
641 subreq = messaging_filtered_read_send(state, ev, msg,
642 messaging_read_filter, state);
643 if (tevent_req_nomem(subreq, req)) {
644 return tevent_req_post(req, ev);
646 tevent_req_set_callback(subreq, messaging_read_done, req);
650 static bool messaging_read_filter(struct messaging_rec *rec,
653 struct messaging_read_state *state = talloc_get_type_abort(
654 private_data, struct messaging_read_state);
656 return rec->msg_type == state->msg_type;
659 static void messaging_read_done(struct tevent_req *subreq)
661 struct tevent_req *req = tevent_req_callback_data(
662 subreq, struct tevent_req);
663 struct messaging_read_state *state = tevent_req_data(
664 req, struct messaging_read_state);
667 ret = messaging_filtered_read_recv(subreq, state, &state->rec);
669 if (tevent_req_error(req, ret)) {
672 tevent_req_done(req);
675 int messaging_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
676 struct messaging_rec **presult)
678 struct messaging_read_state *state = tevent_req_data(
679 req, struct messaging_read_state);
682 if (tevent_req_is_unix_error(req, &err)) {
685 if (presult != NULL) {
686 *presult = talloc_move(mem_ctx, &state->rec);
691 static bool messaging_append_new_waiters(struct messaging_context *msg_ctx)
693 if (msg_ctx->num_new_waiters == 0) {
697 if (talloc_array_length(msg_ctx->waiters) <
698 (msg_ctx->num_waiters + msg_ctx->num_new_waiters)) {
699 struct tevent_req **tmp;
700 tmp = talloc_realloc(
701 msg_ctx, msg_ctx->waiters, struct tevent_req *,
702 msg_ctx->num_waiters + msg_ctx->num_new_waiters);
704 DEBUG(1, ("%s: talloc failed\n", __func__));
707 msg_ctx->waiters = tmp;
710 memcpy(&msg_ctx->waiters[msg_ctx->num_waiters], msg_ctx->new_waiters,
711 sizeof(struct tevent_req *) * msg_ctx->num_new_waiters);
713 msg_ctx->num_waiters += msg_ctx->num_new_waiters;
714 msg_ctx->num_new_waiters = 0;
719 struct messaging_defer_callback_state {
720 struct messaging_context *msg_ctx;
721 struct messaging_rec *rec;
722 void (*fn)(struct messaging_context *msg, void *private_data,
723 uint32_t msg_type, struct server_id server_id,
728 static void messaging_defer_callback_trigger(struct tevent_context *ev,
729 struct tevent_immediate *im,
732 static void messaging_defer_callback(
733 struct messaging_context *msg_ctx, struct messaging_rec *rec,
734 void (*fn)(struct messaging_context *msg, void *private_data,
735 uint32_t msg_type, struct server_id server_id,
739 struct messaging_defer_callback_state *state;
740 struct tevent_immediate *im;
742 state = talloc(msg_ctx, struct messaging_defer_callback_state);
744 DEBUG(1, ("talloc failed\n"));
747 state->msg_ctx = msg_ctx;
749 state->private_data = private_data;
751 state->rec = messaging_rec_dup(state, rec);
752 if (state->rec == NULL) {
753 DEBUG(1, ("talloc failed\n"));
758 im = tevent_create_immediate(state);
760 DEBUG(1, ("tevent_create_immediate failed\n"));
764 tevent_schedule_immediate(im, msg_ctx->event_ctx,
765 messaging_defer_callback_trigger, state);
768 static void messaging_defer_callback_trigger(struct tevent_context *ev,
769 struct tevent_immediate *im,
772 struct messaging_defer_callback_state *state = talloc_get_type_abort(
773 private_data, struct messaging_defer_callback_state);
774 struct messaging_rec *rec = state->rec;
776 state->fn(state->msg_ctx, state->private_data, rec->msg_type, rec->src,
782 Dispatch one messaging_rec
784 void messaging_dispatch_rec(struct messaging_context *msg_ctx,
785 struct messaging_rec *rec)
787 struct messaging_callback *cb, *next;
790 for (cb = msg_ctx->callbacks; cb != NULL; cb = next) {
792 if (cb->msg_type != rec->msg_type) {
796 if (messaging_is_self_send(msg_ctx, &rec->dest)) {
798 * This is a self-send. We are called here from
799 * messaging_send(), and we don't want to directly
800 * recurse into the callback but go via a
803 messaging_defer_callback(msg_ctx, rec, cb->fn,
807 * This comes from a different process. we are called
808 * from the event loop, so we should call back
811 cb->fn(msg_ctx, cb->private_data, rec->msg_type,
812 rec->src, &rec->buf);
815 * we continue looking for matching messages after finding
816 * one. This matters for subsystems like the internal notify
817 * code which register more than one handler for the same
822 if (!messaging_append_new_waiters(msg_ctx)) {
827 while (i < msg_ctx->num_waiters) {
828 struct tevent_req *req;
829 struct messaging_filtered_read_state *state;
831 req = msg_ctx->waiters[i];
834 * This got cleaned up. In the meantime,
835 * move everything down one. We need
836 * to keep the order of waiters, as
837 * other code may depend on this.
839 if (i < msg_ctx->num_waiters - 1) {
840 memmove(&msg_ctx->waiters[i],
841 &msg_ctx->waiters[i+1],
842 sizeof(struct tevent_req *) *
843 (msg_ctx->num_waiters - i - 1));
845 msg_ctx->num_waiters -= 1;
849 state = tevent_req_data(
850 req, struct messaging_filtered_read_state);
851 if (state->filter(rec, state->private_data)) {
852 messaging_filtered_read_done(req, rec);
859 static int mess_parent_dgm_cleanup(void *private_data);
860 static void mess_parent_dgm_cleanup_done(struct tevent_req *req);
862 bool messaging_parent_dgm_cleanup_init(struct messaging_context *msg)
864 struct tevent_req *req;
866 req = background_job_send(
867 msg, msg->event_ctx, msg, NULL, 0,
868 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
870 mess_parent_dgm_cleanup, msg);
874 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
878 static int mess_parent_dgm_cleanup(void *private_data)
880 struct messaging_context *msg_ctx = talloc_get_type_abort(
881 private_data, struct messaging_context);
884 ret = messaging_dgm_wipe(msg_ctx);
885 DEBUG(10, ("messaging_dgm_wipe returned %s\n",
886 ret ? strerror(ret) : "ok"));
887 return lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
891 static void mess_parent_dgm_cleanup_done(struct tevent_req *req)
893 struct messaging_context *msg = tevent_req_callback_data(
894 req, struct messaging_context);
897 status = background_job_recv(req);
899 DEBUG(1, ("messaging dgm cleanup job ended with %s\n",
902 req = background_job_send(
903 msg, msg->event_ctx, msg, NULL, 0,
904 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
906 mess_parent_dgm_cleanup, msg);
908 DEBUG(1, ("background_job_send failed\n"));
910 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
913 struct messaging_backend *messaging_local_backend(
914 struct messaging_context *msg_ctx)
916 return msg_ctx->local;
919 struct tevent_context *messaging_tevent_context(
920 struct messaging_context *msg_ctx)
922 return msg_ctx->event_ctx;