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 struct server_id_buf idbuf;
95 DEBUG(1, ("INFO: Received PING message from PID %s [%.*s]\n",
96 server_id_str_buf(src, &idbuf), (int)data->length,
97 data->data ? (char *)data->data : ""));
99 messaging_send(msg_ctx, src, MSG_PONG, data);
102 /****************************************************************************
103 Register/replace a dispatch function for a particular message type.
104 JRA changed Dec 13 2006. Only one message handler now permitted per type.
105 *NOTE*: Dispatch functions must be able to cope with incoming
106 messages on an *odd* byte boundary.
107 ****************************************************************************/
110 struct messaging_context *msg_ctx;
118 /****************************************************************************
119 Send one of the messages for the broadcast.
120 ****************************************************************************/
122 static int traverse_fn(struct db_record *rec, const struct server_id *id,
123 uint32_t msg_flags, void *state)
125 struct msg_all *msg_all = (struct msg_all *)state;
128 /* Don't send if the receiver hasn't registered an interest. */
130 if((msg_flags & msg_all->msg_flag) == 0) {
134 /* If the msg send fails because the pid was not found (i.e. smbd died),
135 * the msg has already been deleted from the messages.tdb.*/
137 status = messaging_send_buf(msg_all->msg_ctx, *id, msg_all->msg_type,
138 (const uint8_t *)msg_all->buf, msg_all->len);
140 if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
141 struct server_id_buf idbuf;
144 * If the pid was not found delete the entry from
148 DEBUG(2, ("pid %s doesn't exist\n",
149 server_id_str_buf(*id, &idbuf)));
151 dbwrap_record_delete(rec);
158 * Send a message to all smbd processes.
160 * It isn't very efficient, but should be OK for the sorts of
161 * applications that use it. When we need efficient broadcast we can add
164 * @param n_sent Set to the number of messages sent. This should be
165 * equal to the number of processes, but be careful for races.
167 * @retval True for success.
169 bool message_send_all(struct messaging_context *msg_ctx,
171 const void *buf, size_t len,
174 struct msg_all msg_all;
176 msg_all.msg_type = msg_type;
177 if (msg_type < 0x100) {
178 msg_all.msg_flag = FLAG_MSG_GENERAL;
179 } else if (msg_type > 0x100 && msg_type < 0x200) {
180 msg_all.msg_flag = FLAG_MSG_NMBD;
181 } else if (msg_type > 0x200 && msg_type < 0x300) {
182 msg_all.msg_flag = FLAG_MSG_PRINT_GENERAL;
183 } else if (msg_type > 0x300 && msg_type < 0x400) {
184 msg_all.msg_flag = FLAG_MSG_SMBD;
185 } else if (msg_type > 0x400 && msg_type < 0x600) {
186 msg_all.msg_flag = FLAG_MSG_WINBIND;
187 } else if (msg_type > 4000 && msg_type < 5000) {
188 msg_all.msg_flag = FLAG_MSG_DBWRAP;
196 msg_all.msg_ctx = msg_ctx;
198 serverid_traverse(traverse_fn, &msg_all);
200 *n_sent = msg_all.n_sent;
204 static void messaging_recv_cb(int msg_type,
205 struct server_id src, struct server_id dst,
206 const uint8_t *msg, size_t msg_len,
209 struct messaging_context *msg_ctx = talloc_get_type_abort(
210 private_data, struct messaging_context);
211 struct messaging_rec rec;
213 rec = (struct messaging_rec) {
214 .msg_version = MESSAGE_VERSION,
215 .msg_type = msg_type,
218 .buf.data = discard_const_p(uint8, msg),
219 .buf.length = msg_len
222 messaging_dispatch_rec(msg_ctx, &rec);
225 struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx,
226 struct tevent_context *ev)
228 struct messaging_context *ctx;
231 static bool have_context = false;
234 DEBUG(0, ("No two messaging contexts per process\n"));
239 if (!(ctx = talloc_zero(mem_ctx, struct messaging_context))) {
243 ctx->id = procid_self();
245 ctx->have_context = &have_context;
247 ret = messaging_dgm_init(ctx, ctx, ctx->event_ctx, &ctx->local,
248 messaging_recv_cb, ctx);
251 DEBUG(2, ("messaging_dgm_init failed: %s\n", strerror(ret)));
256 if (lp_clustering()) {
257 status = messaging_ctdbd_init(ctx, ctx, &ctx->remote);
259 if (!NT_STATUS_IS_OK(status)) {
260 DEBUG(2, ("messaging_ctdbd_init failed: %s\n",
266 ctx->id.vnn = get_my_vnn();
268 messaging_register(ctx, NULL, MSG_PING, ping_message);
270 /* Register some debugging related messages */
272 register_msg_pool_usage(ctx);
273 register_dmalloc_msgs(ctx);
274 debug_register_msgs(ctx);
277 talloc_set_destructor(ctx, messaging_context_destructor);
282 static int messaging_context_destructor(struct messaging_context *msg_ctx)
284 SMB_ASSERT(*msg_ctx->have_context);
285 *msg_ctx->have_context = false;
289 struct server_id messaging_server_id(const struct messaging_context *msg_ctx)
295 * re-init after a fork
297 NTSTATUS messaging_reinit(struct messaging_context *msg_ctx)
302 TALLOC_FREE(msg_ctx->local);
304 msg_ctx->id = procid_self();
306 ret = messaging_dgm_init(msg_ctx, msg_ctx, msg_ctx->event_ctx,
308 messaging_recv_cb, msg_ctx);
310 DEBUG(0, ("messaging_dgm_init failed: %s\n", strerror(errno)));
311 return map_nt_error_from_unix(ret);
314 TALLOC_FREE(msg_ctx->remote);
316 if (lp_clustering()) {
317 status = messaging_ctdbd_init(msg_ctx, msg_ctx,
320 if (!NT_STATUS_IS_OK(status)) {
321 DEBUG(1, ("messaging_ctdbd_init failed: %s\n",
332 * Register a dispatch function for a particular message type. Allow multiple
335 NTSTATUS messaging_register(struct messaging_context *msg_ctx,
338 void (*fn)(struct messaging_context *msg,
341 struct server_id server_id,
344 struct messaging_callback *cb;
346 DEBUG(5, ("Registering messaging pointer for type %u - "
348 (unsigned)msg_type, private_data));
351 * Only one callback per type
354 for (cb = msg_ctx->callbacks; cb != NULL; cb = cb->next) {
355 /* we allow a second registration of the same message
356 type if it has a different private pointer. This is
357 needed in, for example, the internal notify code,
358 which creates a new notify context for each tree
359 connect, and expects to receive messages to each of
361 if (cb->msg_type == msg_type && private_data == cb->private_data) {
362 DEBUG(5,("Overriding messaging pointer for type %u - private_data=%p\n",
363 (unsigned)msg_type, private_data));
365 cb->private_data = private_data;
370 if (!(cb = talloc(msg_ctx, struct messaging_callback))) {
371 return NT_STATUS_NO_MEMORY;
374 cb->msg_type = msg_type;
376 cb->private_data = private_data;
378 DLIST_ADD(msg_ctx->callbacks, cb);
383 De-register the function for a particular message type.
385 void messaging_deregister(struct messaging_context *ctx, uint32_t msg_type,
388 struct messaging_callback *cb, *next;
390 for (cb = ctx->callbacks; cb; cb = next) {
392 if ((cb->msg_type == msg_type)
393 && (cb->private_data == private_data)) {
394 DEBUG(5,("Deregistering messaging pointer for type %u - private_data=%p\n",
395 (unsigned)msg_type, private_data));
396 DLIST_REMOVE(ctx->callbacks, cb);
402 static bool messaging_is_self_send(const struct messaging_context *msg_ctx,
403 const struct server_id *dst)
405 return ((msg_ctx->id.vnn == dst->vnn) &&
406 (msg_ctx->id.pid == dst->pid));
410 Send a message to a particular server
412 NTSTATUS messaging_send(struct messaging_context *msg_ctx,
413 struct server_id server, uint32_t msg_type,
414 const DATA_BLOB *data)
418 iov.iov_base = data->data;
419 iov.iov_len = data->length;
421 return messaging_send_iov(msg_ctx, server, msg_type, &iov, 1);
424 NTSTATUS messaging_send_buf(struct messaging_context *msg_ctx,
425 struct server_id server, uint32_t msg_type,
426 const uint8_t *buf, size_t len)
428 DATA_BLOB blob = data_blob_const(buf, len);
429 return messaging_send(msg_ctx, server, msg_type, &blob);
432 NTSTATUS messaging_send_iov(struct messaging_context *msg_ctx,
433 struct server_id server, uint32_t msg_type,
434 const struct iovec *iov, int iovlen)
438 if (server_id_is_disconnected(&server)) {
439 return NT_STATUS_INVALID_PARAMETER_MIX;
442 if (!procid_is_local(&server)) {
443 ret = msg_ctx->remote->send_fn(msg_ctx->id, server,
444 msg_type, iov, iovlen,
447 return map_nt_error_from_unix(ret);
452 if (messaging_is_self_send(msg_ctx, &server)) {
453 struct messaging_rec rec;
456 buf = iov_buf(talloc_tos(), iov, iovlen);
458 return NT_STATUS_NO_MEMORY;
461 rec.msg_version = MESSAGE_VERSION;
462 rec.msg_type = msg_type & MSG_TYPE_MASK;
464 rec.src = msg_ctx->id;
465 rec.buf = data_blob_const(buf, talloc_get_size(buf));
466 messaging_dispatch_rec(msg_ctx, &rec);
471 ret = msg_ctx->local->send_fn(msg_ctx->id, server, msg_type,
472 iov, iovlen, msg_ctx->local);
474 return map_nt_error_from_unix(ret);
479 static struct messaging_rec *messaging_rec_dup(TALLOC_CTX *mem_ctx,
480 struct messaging_rec *rec)
482 struct messaging_rec *result;
484 result = talloc_pooled_object(mem_ctx, struct messaging_rec,
486 if (result == NULL) {
491 /* Doesn't fail, see talloc_pooled_object */
493 result->buf.data = talloc_memdup(result, rec->buf.data,
498 struct messaging_filtered_read_state {
499 struct tevent_context *ev;
500 struct messaging_context *msg_ctx;
503 bool (*filter)(struct messaging_rec *rec, void *private_data);
506 struct messaging_rec *rec;
509 static void messaging_filtered_read_cleanup(struct tevent_req *req,
510 enum tevent_req_state req_state);
512 struct tevent_req *messaging_filtered_read_send(
513 TALLOC_CTX *mem_ctx, struct tevent_context *ev,
514 struct messaging_context *msg_ctx,
515 bool (*filter)(struct messaging_rec *rec, void *private_data),
518 struct tevent_req *req;
519 struct messaging_filtered_read_state *state;
520 size_t new_waiters_len;
522 req = tevent_req_create(mem_ctx, &state,
523 struct messaging_filtered_read_state);
528 state->msg_ctx = msg_ctx;
529 state->filter = filter;
530 state->private_data = private_data;
533 * We have to defer the callback here, as we might be called from
534 * within a different tevent_context than state->ev
536 tevent_req_defer_callback(req, state->ev);
538 state->tevent_handle = messaging_dgm_register_tevent_context(
540 if (tevent_req_nomem(state, req)) {
541 return tevent_req_post(req, ev);
545 * We add ourselves to the "new_waiters" array, not the "waiters"
546 * array. If we are called from within messaging_read_done,
547 * messaging_dispatch_rec will be in an active for-loop on
548 * "waiters". We must be careful not to mess with this array, because
549 * it could mean that a single event is being delivered twice.
552 new_waiters_len = talloc_array_length(msg_ctx->new_waiters);
554 if (new_waiters_len == msg_ctx->num_new_waiters) {
555 struct tevent_req **tmp;
557 tmp = talloc_realloc(msg_ctx, msg_ctx->new_waiters,
558 struct tevent_req *, new_waiters_len+1);
559 if (tevent_req_nomem(tmp, req)) {
560 return tevent_req_post(req, ev);
562 msg_ctx->new_waiters = tmp;
565 msg_ctx->new_waiters[msg_ctx->num_new_waiters] = req;
566 msg_ctx->num_new_waiters += 1;
567 tevent_req_set_cleanup_fn(req, messaging_filtered_read_cleanup);
572 static void messaging_filtered_read_cleanup(struct tevent_req *req,
573 enum tevent_req_state req_state)
575 struct messaging_filtered_read_state *state = tevent_req_data(
576 req, struct messaging_filtered_read_state);
577 struct messaging_context *msg_ctx = state->msg_ctx;
580 tevent_req_set_cleanup_fn(req, NULL);
582 TALLOC_FREE(state->tevent_handle);
585 * Just set the [new_]waiters entry to NULL, be careful not to mess
586 * with the other "waiters" array contents. We are often called from
587 * within "messaging_dispatch_rec", which loops over
588 * "waiters". Messing with the "waiters" array will mess up that
592 for (i=0; i<msg_ctx->num_waiters; i++) {
593 if (msg_ctx->waiters[i] == req) {
594 msg_ctx->waiters[i] = NULL;
599 for (i=0; i<msg_ctx->num_new_waiters; i++) {
600 if (msg_ctx->new_waiters[i] == req) {
601 msg_ctx->new_waiters[i] = NULL;
607 static void messaging_filtered_read_done(struct tevent_req *req,
608 struct messaging_rec *rec)
610 struct messaging_filtered_read_state *state = tevent_req_data(
611 req, struct messaging_filtered_read_state);
613 state->rec = messaging_rec_dup(state, rec);
614 if (tevent_req_nomem(state->rec, req)) {
617 tevent_req_done(req);
620 int messaging_filtered_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
621 struct messaging_rec **presult)
623 struct messaging_filtered_read_state *state = tevent_req_data(
624 req, struct messaging_filtered_read_state);
627 if (tevent_req_is_unix_error(req, &err)) {
628 tevent_req_received(req);
631 *presult = talloc_move(mem_ctx, &state->rec);
635 struct messaging_read_state {
637 struct messaging_rec *rec;
640 static bool messaging_read_filter(struct messaging_rec *rec,
642 static void messaging_read_done(struct tevent_req *subreq);
644 struct tevent_req *messaging_read_send(TALLOC_CTX *mem_ctx,
645 struct tevent_context *ev,
646 struct messaging_context *msg,
649 struct tevent_req *req, *subreq;
650 struct messaging_read_state *state;
652 req = tevent_req_create(mem_ctx, &state,
653 struct messaging_read_state);
657 state->msg_type = msg_type;
659 subreq = messaging_filtered_read_send(state, ev, msg,
660 messaging_read_filter, state);
661 if (tevent_req_nomem(subreq, req)) {
662 return tevent_req_post(req, ev);
664 tevent_req_set_callback(subreq, messaging_read_done, req);
668 static bool messaging_read_filter(struct messaging_rec *rec,
671 struct messaging_read_state *state = talloc_get_type_abort(
672 private_data, struct messaging_read_state);
674 return rec->msg_type == state->msg_type;
677 static void messaging_read_done(struct tevent_req *subreq)
679 struct tevent_req *req = tevent_req_callback_data(
680 subreq, struct tevent_req);
681 struct messaging_read_state *state = tevent_req_data(
682 req, struct messaging_read_state);
685 ret = messaging_filtered_read_recv(subreq, state, &state->rec);
687 if (tevent_req_error(req, ret)) {
690 tevent_req_done(req);
693 int messaging_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
694 struct messaging_rec **presult)
696 struct messaging_read_state *state = tevent_req_data(
697 req, struct messaging_read_state);
700 if (tevent_req_is_unix_error(req, &err)) {
703 if (presult != NULL) {
704 *presult = talloc_move(mem_ctx, &state->rec);
709 static bool messaging_append_new_waiters(struct messaging_context *msg_ctx)
711 if (msg_ctx->num_new_waiters == 0) {
715 if (talloc_array_length(msg_ctx->waiters) <
716 (msg_ctx->num_waiters + msg_ctx->num_new_waiters)) {
717 struct tevent_req **tmp;
718 tmp = talloc_realloc(
719 msg_ctx, msg_ctx->waiters, struct tevent_req *,
720 msg_ctx->num_waiters + msg_ctx->num_new_waiters);
722 DEBUG(1, ("%s: talloc failed\n", __func__));
725 msg_ctx->waiters = tmp;
728 memcpy(&msg_ctx->waiters[msg_ctx->num_waiters], msg_ctx->new_waiters,
729 sizeof(struct tevent_req *) * msg_ctx->num_new_waiters);
731 msg_ctx->num_waiters += msg_ctx->num_new_waiters;
732 msg_ctx->num_new_waiters = 0;
737 struct messaging_defer_callback_state {
738 struct messaging_context *msg_ctx;
739 struct messaging_rec *rec;
740 void (*fn)(struct messaging_context *msg, void *private_data,
741 uint32_t msg_type, struct server_id server_id,
746 static void messaging_defer_callback_trigger(struct tevent_context *ev,
747 struct tevent_immediate *im,
750 static void messaging_defer_callback(
751 struct messaging_context *msg_ctx, struct messaging_rec *rec,
752 void (*fn)(struct messaging_context *msg, void *private_data,
753 uint32_t msg_type, struct server_id server_id,
757 struct messaging_defer_callback_state *state;
758 struct tevent_immediate *im;
760 state = talloc(msg_ctx, struct messaging_defer_callback_state);
762 DEBUG(1, ("talloc failed\n"));
765 state->msg_ctx = msg_ctx;
767 state->private_data = private_data;
769 state->rec = messaging_rec_dup(state, rec);
770 if (state->rec == NULL) {
771 DEBUG(1, ("talloc failed\n"));
776 im = tevent_create_immediate(state);
778 DEBUG(1, ("tevent_create_immediate failed\n"));
782 tevent_schedule_immediate(im, msg_ctx->event_ctx,
783 messaging_defer_callback_trigger, state);
786 static void messaging_defer_callback_trigger(struct tevent_context *ev,
787 struct tevent_immediate *im,
790 struct messaging_defer_callback_state *state = talloc_get_type_abort(
791 private_data, struct messaging_defer_callback_state);
792 struct messaging_rec *rec = state->rec;
794 state->fn(state->msg_ctx, state->private_data, rec->msg_type, rec->src,
800 Dispatch one messaging_rec
802 void messaging_dispatch_rec(struct messaging_context *msg_ctx,
803 struct messaging_rec *rec)
805 struct messaging_callback *cb, *next;
808 for (cb = msg_ctx->callbacks; cb != NULL; cb = next) {
810 if (cb->msg_type != rec->msg_type) {
814 if (messaging_is_self_send(msg_ctx, &rec->dest)) {
816 * This is a self-send. We are called here from
817 * messaging_send(), and we don't want to directly
818 * recurse into the callback but go via a
821 messaging_defer_callback(msg_ctx, rec, cb->fn,
825 * This comes from a different process. we are called
826 * from the event loop, so we should call back
829 cb->fn(msg_ctx, cb->private_data, rec->msg_type,
830 rec->src, &rec->buf);
833 * we continue looking for matching messages after finding
834 * one. This matters for subsystems like the internal notify
835 * code which register more than one handler for the same
840 if (!messaging_append_new_waiters(msg_ctx)) {
845 while (i < msg_ctx->num_waiters) {
846 struct tevent_req *req;
847 struct messaging_filtered_read_state *state;
849 req = msg_ctx->waiters[i];
852 * This got cleaned up. In the meantime,
853 * move everything down one. We need
854 * to keep the order of waiters, as
855 * other code may depend on this.
857 if (i < msg_ctx->num_waiters - 1) {
858 memmove(&msg_ctx->waiters[i],
859 &msg_ctx->waiters[i+1],
860 sizeof(struct tevent_req *) *
861 (msg_ctx->num_waiters - i - 1));
863 msg_ctx->num_waiters -= 1;
867 state = tevent_req_data(
868 req, struct messaging_filtered_read_state);
869 if (state->filter(rec, state->private_data)) {
870 messaging_filtered_read_done(req, rec);
877 static int mess_parent_dgm_cleanup(void *private_data);
878 static void mess_parent_dgm_cleanup_done(struct tevent_req *req);
880 bool messaging_parent_dgm_cleanup_init(struct messaging_context *msg)
882 struct tevent_req *req;
884 req = background_job_send(
885 msg, msg->event_ctx, msg, NULL, 0,
886 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
888 mess_parent_dgm_cleanup, msg);
892 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
896 static int mess_parent_dgm_cleanup(void *private_data)
898 struct messaging_context *msg_ctx = talloc_get_type_abort(
899 private_data, struct messaging_context);
902 ret = messaging_dgm_wipe(msg_ctx);
903 DEBUG(10, ("messaging_dgm_wipe returned %s\n",
904 ret ? strerror(ret) : "ok"));
905 return lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
909 static void mess_parent_dgm_cleanup_done(struct tevent_req *req)
911 struct messaging_context *msg = tevent_req_callback_data(
912 req, struct messaging_context);
915 status = background_job_recv(req);
917 DEBUG(1, ("messaging dgm cleanup job ended with %s\n",
920 req = background_job_send(
921 msg, msg->event_ctx, msg, NULL, 0,
922 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
924 mess_parent_dgm_cleanup, msg);
926 DEBUG(1, ("background_job_send failed\n"));
928 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
931 struct messaging_backend *messaging_local_backend(
932 struct messaging_context *msg_ctx)
934 return msg_ctx->local;
937 struct tevent_context *messaging_tevent_context(
938 struct messaging_context *msg_ctx)
940 return msg_ctx->event_ctx;