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 struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx,
205 struct tevent_context *ev)
207 struct messaging_context *ctx;
210 static bool have_context = false;
213 DEBUG(0, ("No two messaging contexts per process\n"));
218 if (!(ctx = talloc_zero(mem_ctx, struct messaging_context))) {
222 ctx->id = procid_self();
224 ctx->have_context = &have_context;
226 ret = messaging_dgm_init(ctx, ctx, &ctx->local);
229 DEBUG(2, ("messaging_dgm_init failed: %s\n", strerror(ret)));
234 if (lp_clustering()) {
235 status = messaging_ctdbd_init(ctx, ctx, &ctx->remote);
237 if (!NT_STATUS_IS_OK(status)) {
238 DEBUG(2, ("messaging_ctdbd_init failed: %s\n",
244 ctx->id.vnn = get_my_vnn();
246 messaging_register(ctx, NULL, MSG_PING, ping_message);
248 /* Register some debugging related messages */
250 register_msg_pool_usage(ctx);
251 register_dmalloc_msgs(ctx);
252 debug_register_msgs(ctx);
255 talloc_set_destructor(ctx, messaging_context_destructor);
260 static int messaging_context_destructor(struct messaging_context *msg_ctx)
262 SMB_ASSERT(*msg_ctx->have_context);
263 *msg_ctx->have_context = false;
267 struct server_id messaging_server_id(const struct messaging_context *msg_ctx)
273 * re-init after a fork
275 NTSTATUS messaging_reinit(struct messaging_context *msg_ctx)
280 TALLOC_FREE(msg_ctx->local);
282 msg_ctx->id = procid_self();
284 ret = messaging_dgm_init(msg_ctx, msg_ctx, &msg_ctx->local);
286 DEBUG(0, ("messaging_dgm_init failed: %s\n", strerror(errno)));
287 return map_nt_error_from_unix(ret);
290 TALLOC_FREE(msg_ctx->remote);
292 if (lp_clustering()) {
293 status = messaging_ctdbd_init(msg_ctx, msg_ctx,
296 if (!NT_STATUS_IS_OK(status)) {
297 DEBUG(1, ("messaging_ctdbd_init failed: %s\n",
308 * Register a dispatch function for a particular message type. Allow multiple
311 NTSTATUS messaging_register(struct messaging_context *msg_ctx,
314 void (*fn)(struct messaging_context *msg,
317 struct server_id server_id,
320 struct messaging_callback *cb;
322 DEBUG(5, ("Registering messaging pointer for type %u - "
324 (unsigned)msg_type, private_data));
327 * Only one callback per type
330 for (cb = msg_ctx->callbacks; cb != NULL; cb = cb->next) {
331 /* we allow a second registration of the same message
332 type if it has a different private pointer. This is
333 needed in, for example, the internal notify code,
334 which creates a new notify context for each tree
335 connect, and expects to receive messages to each of
337 if (cb->msg_type == msg_type && private_data == cb->private_data) {
338 DEBUG(5,("Overriding messaging pointer for type %u - private_data=%p\n",
339 (unsigned)msg_type, private_data));
341 cb->private_data = private_data;
346 if (!(cb = talloc(msg_ctx, struct messaging_callback))) {
347 return NT_STATUS_NO_MEMORY;
350 cb->msg_type = msg_type;
352 cb->private_data = private_data;
354 DLIST_ADD(msg_ctx->callbacks, cb);
359 De-register the function for a particular message type.
361 void messaging_deregister(struct messaging_context *ctx, uint32_t msg_type,
364 struct messaging_callback *cb, *next;
366 for (cb = ctx->callbacks; cb; cb = next) {
368 if ((cb->msg_type == msg_type)
369 && (cb->private_data == private_data)) {
370 DEBUG(5,("Deregistering messaging pointer for type %u - private_data=%p\n",
371 (unsigned)msg_type, private_data));
372 DLIST_REMOVE(ctx->callbacks, cb);
378 static bool messaging_is_self_send(const struct messaging_context *msg_ctx,
379 const struct server_id *dst)
381 return ((msg_ctx->id.vnn == dst->vnn) &&
382 (msg_ctx->id.pid == dst->pid));
386 Send a message to a particular server
388 NTSTATUS messaging_send(struct messaging_context *msg_ctx,
389 struct server_id server, uint32_t msg_type,
390 const DATA_BLOB *data)
394 iov.iov_base = data->data;
395 iov.iov_len = data->length;
397 return messaging_send_iov(msg_ctx, server, msg_type, &iov, 1);
400 NTSTATUS messaging_send_buf(struct messaging_context *msg_ctx,
401 struct server_id server, uint32_t msg_type,
402 const uint8_t *buf, size_t len)
404 DATA_BLOB blob = data_blob_const(buf, len);
405 return messaging_send(msg_ctx, server, msg_type, &blob);
408 NTSTATUS messaging_send_iov(struct messaging_context *msg_ctx,
409 struct server_id server, uint32_t msg_type,
410 const struct iovec *iov, int iovlen)
414 if (server_id_is_disconnected(&server)) {
415 return NT_STATUS_INVALID_PARAMETER_MIX;
418 if (!procid_is_local(&server)) {
419 ret = msg_ctx->remote->send_fn(msg_ctx->id, server,
420 msg_type, iov, iovlen,
423 return map_nt_error_from_unix(ret);
428 if (messaging_is_self_send(msg_ctx, &server)) {
429 struct messaging_rec rec;
432 buf = iov_buf(talloc_tos(), iov, iovlen);
434 return NT_STATUS_NO_MEMORY;
437 rec.msg_version = MESSAGE_VERSION;
438 rec.msg_type = msg_type & MSG_TYPE_MASK;
440 rec.src = msg_ctx->id;
441 rec.buf = data_blob_const(buf, talloc_get_size(buf));
442 messaging_dispatch_rec(msg_ctx, &rec);
447 ret = msg_ctx->local->send_fn(msg_ctx->id, server, msg_type,
448 iov, iovlen, msg_ctx->local);
450 return map_nt_error_from_unix(ret);
455 static struct messaging_rec *messaging_rec_dup(TALLOC_CTX *mem_ctx,
456 struct messaging_rec *rec)
458 struct messaging_rec *result;
460 result = talloc_pooled_object(mem_ctx, struct messaging_rec,
462 if (result == NULL) {
467 /* Doesn't fail, see talloc_pooled_object */
469 result->buf.data = talloc_memdup(result, rec->buf.data,
474 struct messaging_filtered_read_state {
475 struct tevent_context *ev;
476 struct messaging_context *msg_ctx;
479 bool (*filter)(struct messaging_rec *rec, void *private_data);
482 struct messaging_rec *rec;
485 static void messaging_filtered_read_cleanup(struct tevent_req *req,
486 enum tevent_req_state req_state);
488 struct tevent_req *messaging_filtered_read_send(
489 TALLOC_CTX *mem_ctx, struct tevent_context *ev,
490 struct messaging_context *msg_ctx,
491 bool (*filter)(struct messaging_rec *rec, void *private_data),
494 struct tevent_req *req;
495 struct messaging_filtered_read_state *state;
496 size_t new_waiters_len;
498 req = tevent_req_create(mem_ctx, &state,
499 struct messaging_filtered_read_state);
504 state->msg_ctx = msg_ctx;
505 state->filter = filter;
506 state->private_data = private_data;
509 * We have to defer the callback here, as we might be called from
510 * within a different tevent_context than state->ev
512 tevent_req_defer_callback(req, state->ev);
514 state->tevent_handle = messaging_dgm_register_tevent_context(
516 if (tevent_req_nomem(state, req)) {
517 return tevent_req_post(req, ev);
521 * We add ourselves to the "new_waiters" array, not the "waiters"
522 * array. If we are called from within messaging_read_done,
523 * messaging_dispatch_rec will be in an active for-loop on
524 * "waiters". We must be careful not to mess with this array, because
525 * it could mean that a single event is being delivered twice.
528 new_waiters_len = talloc_array_length(msg_ctx->new_waiters);
530 if (new_waiters_len == msg_ctx->num_new_waiters) {
531 struct tevent_req **tmp;
533 tmp = talloc_realloc(msg_ctx, msg_ctx->new_waiters,
534 struct tevent_req *, new_waiters_len+1);
535 if (tevent_req_nomem(tmp, req)) {
536 return tevent_req_post(req, ev);
538 msg_ctx->new_waiters = tmp;
541 msg_ctx->new_waiters[msg_ctx->num_new_waiters] = req;
542 msg_ctx->num_new_waiters += 1;
543 tevent_req_set_cleanup_fn(req, messaging_filtered_read_cleanup);
548 static void messaging_filtered_read_cleanup(struct tevent_req *req,
549 enum tevent_req_state req_state)
551 struct messaging_filtered_read_state *state = tevent_req_data(
552 req, struct messaging_filtered_read_state);
553 struct messaging_context *msg_ctx = state->msg_ctx;
556 tevent_req_set_cleanup_fn(req, NULL);
558 TALLOC_FREE(state->tevent_handle);
561 * Just set the [new_]waiters entry to NULL, be careful not to mess
562 * with the other "waiters" array contents. We are often called from
563 * within "messaging_dispatch_rec", which loops over
564 * "waiters". Messing with the "waiters" array will mess up that
568 for (i=0; i<msg_ctx->num_waiters; i++) {
569 if (msg_ctx->waiters[i] == req) {
570 msg_ctx->waiters[i] = NULL;
575 for (i=0; i<msg_ctx->num_new_waiters; i++) {
576 if (msg_ctx->new_waiters[i] == req) {
577 msg_ctx->new_waiters[i] = NULL;
583 static void messaging_filtered_read_done(struct tevent_req *req,
584 struct messaging_rec *rec)
586 struct messaging_filtered_read_state *state = tevent_req_data(
587 req, struct messaging_filtered_read_state);
589 state->rec = messaging_rec_dup(state, rec);
590 if (tevent_req_nomem(state->rec, req)) {
593 tevent_req_done(req);
596 int messaging_filtered_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
597 struct messaging_rec **presult)
599 struct messaging_filtered_read_state *state = tevent_req_data(
600 req, struct messaging_filtered_read_state);
603 if (tevent_req_is_unix_error(req, &err)) {
604 tevent_req_received(req);
607 *presult = talloc_move(mem_ctx, &state->rec);
611 struct messaging_read_state {
613 struct messaging_rec *rec;
616 static bool messaging_read_filter(struct messaging_rec *rec,
618 static void messaging_read_done(struct tevent_req *subreq);
620 struct tevent_req *messaging_read_send(TALLOC_CTX *mem_ctx,
621 struct tevent_context *ev,
622 struct messaging_context *msg,
625 struct tevent_req *req, *subreq;
626 struct messaging_read_state *state;
628 req = tevent_req_create(mem_ctx, &state,
629 struct messaging_read_state);
633 state->msg_type = msg_type;
635 subreq = messaging_filtered_read_send(state, ev, msg,
636 messaging_read_filter, state);
637 if (tevent_req_nomem(subreq, req)) {
638 return tevent_req_post(req, ev);
640 tevent_req_set_callback(subreq, messaging_read_done, req);
644 static bool messaging_read_filter(struct messaging_rec *rec,
647 struct messaging_read_state *state = talloc_get_type_abort(
648 private_data, struct messaging_read_state);
650 return rec->msg_type == state->msg_type;
653 static void messaging_read_done(struct tevent_req *subreq)
655 struct tevent_req *req = tevent_req_callback_data(
656 subreq, struct tevent_req);
657 struct messaging_read_state *state = tevent_req_data(
658 req, struct messaging_read_state);
661 ret = messaging_filtered_read_recv(subreq, state, &state->rec);
663 if (tevent_req_error(req, ret)) {
666 tevent_req_done(req);
669 int messaging_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
670 struct messaging_rec **presult)
672 struct messaging_read_state *state = tevent_req_data(
673 req, struct messaging_read_state);
676 if (tevent_req_is_unix_error(req, &err)) {
679 if (presult != NULL) {
680 *presult = talloc_move(mem_ctx, &state->rec);
685 static bool messaging_append_new_waiters(struct messaging_context *msg_ctx)
687 if (msg_ctx->num_new_waiters == 0) {
691 if (talloc_array_length(msg_ctx->waiters) <
692 (msg_ctx->num_waiters + msg_ctx->num_new_waiters)) {
693 struct tevent_req **tmp;
694 tmp = talloc_realloc(
695 msg_ctx, msg_ctx->waiters, struct tevent_req *,
696 msg_ctx->num_waiters + msg_ctx->num_new_waiters);
698 DEBUG(1, ("%s: talloc failed\n", __func__));
701 msg_ctx->waiters = tmp;
704 memcpy(&msg_ctx->waiters[msg_ctx->num_waiters], msg_ctx->new_waiters,
705 sizeof(struct tevent_req *) * msg_ctx->num_new_waiters);
707 msg_ctx->num_waiters += msg_ctx->num_new_waiters;
708 msg_ctx->num_new_waiters = 0;
713 struct messaging_defer_callback_state {
714 struct messaging_context *msg_ctx;
715 struct messaging_rec *rec;
716 void (*fn)(struct messaging_context *msg, void *private_data,
717 uint32_t msg_type, struct server_id server_id,
722 static void messaging_defer_callback_trigger(struct tevent_context *ev,
723 struct tevent_immediate *im,
726 static void messaging_defer_callback(
727 struct messaging_context *msg_ctx, struct messaging_rec *rec,
728 void (*fn)(struct messaging_context *msg, void *private_data,
729 uint32_t msg_type, struct server_id server_id,
733 struct messaging_defer_callback_state *state;
734 struct tevent_immediate *im;
736 state = talloc(msg_ctx, struct messaging_defer_callback_state);
738 DEBUG(1, ("talloc failed\n"));
741 state->msg_ctx = msg_ctx;
743 state->private_data = private_data;
745 state->rec = messaging_rec_dup(state, rec);
746 if (state->rec == NULL) {
747 DEBUG(1, ("talloc failed\n"));
752 im = tevent_create_immediate(state);
754 DEBUG(1, ("tevent_create_immediate failed\n"));
758 tevent_schedule_immediate(im, msg_ctx->event_ctx,
759 messaging_defer_callback_trigger, state);
762 static void messaging_defer_callback_trigger(struct tevent_context *ev,
763 struct tevent_immediate *im,
766 struct messaging_defer_callback_state *state = talloc_get_type_abort(
767 private_data, struct messaging_defer_callback_state);
768 struct messaging_rec *rec = state->rec;
770 state->fn(state->msg_ctx, state->private_data, rec->msg_type, rec->src,
776 Dispatch one messaging_rec
778 void messaging_dispatch_rec(struct messaging_context *msg_ctx,
779 struct messaging_rec *rec)
781 struct messaging_callback *cb, *next;
784 for (cb = msg_ctx->callbacks; cb != NULL; cb = next) {
786 if (cb->msg_type != rec->msg_type) {
790 if (messaging_is_self_send(msg_ctx, &rec->dest)) {
792 * This is a self-send. We are called here from
793 * messaging_send(), and we don't want to directly
794 * recurse into the callback but go via a
797 messaging_defer_callback(msg_ctx, rec, cb->fn,
801 * This comes from a different process. we are called
802 * from the event loop, so we should call back
805 cb->fn(msg_ctx, cb->private_data, rec->msg_type,
806 rec->src, &rec->buf);
809 * we continue looking for matching messages after finding
810 * one. This matters for subsystems like the internal notify
811 * code which register more than one handler for the same
816 if (!messaging_append_new_waiters(msg_ctx)) {
821 while (i < msg_ctx->num_waiters) {
822 struct tevent_req *req;
823 struct messaging_filtered_read_state *state;
825 req = msg_ctx->waiters[i];
828 * This got cleaned up. In the meantime,
829 * move everything down one. We need
830 * to keep the order of waiters, as
831 * other code may depend on this.
833 if (i < msg_ctx->num_waiters - 1) {
834 memmove(&msg_ctx->waiters[i],
835 &msg_ctx->waiters[i+1],
836 sizeof(struct tevent_req *) *
837 (msg_ctx->num_waiters - i - 1));
839 msg_ctx->num_waiters -= 1;
843 state = tevent_req_data(
844 req, struct messaging_filtered_read_state);
845 if (state->filter(rec, state->private_data)) {
846 messaging_filtered_read_done(req, rec);
853 static int mess_parent_dgm_cleanup(void *private_data);
854 static void mess_parent_dgm_cleanup_done(struct tevent_req *req);
856 bool messaging_parent_dgm_cleanup_init(struct messaging_context *msg)
858 struct tevent_req *req;
860 req = background_job_send(
861 msg, msg->event_ctx, msg, NULL, 0,
862 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
864 mess_parent_dgm_cleanup, msg);
868 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
872 static int mess_parent_dgm_cleanup(void *private_data)
874 struct messaging_context *msg_ctx = talloc_get_type_abort(
875 private_data, struct messaging_context);
878 ret = messaging_dgm_wipe(msg_ctx);
879 DEBUG(10, ("messaging_dgm_wipe returned %s\n",
880 ret ? strerror(ret) : "ok"));
881 return lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
885 static void mess_parent_dgm_cleanup_done(struct tevent_req *req)
887 struct messaging_context *msg = tevent_req_callback_data(
888 req, struct messaging_context);
891 status = background_job_recv(req);
893 DEBUG(1, ("messaging dgm cleanup job ended with %s\n",
896 req = background_job_send(
897 msg, msg->event_ctx, msg, NULL, 0,
898 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
900 mess_parent_dgm_cleanup, msg);
902 DEBUG(1, ("background_job_send failed\n"));
904 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
907 struct messaging_backend *messaging_local_backend(
908 struct messaging_context *msg_ctx)
910 return msg_ctx->local;
913 struct tevent_context *messaging_tevent_context(
914 struct messaging_context *msg_ctx)
916 return msg_ctx->event_ctx;