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"
54 #include "lib/messages_dgm.h"
56 struct messaging_callback {
57 struct messaging_callback *prev, *next;
59 void (*fn)(struct messaging_context *msg, void *private_data,
61 struct server_id server_id, DATA_BLOB *data);
65 struct messaging_context {
67 struct tevent_context *event_ctx;
68 struct messaging_callback *callbacks;
70 struct tevent_req **new_waiters;
71 unsigned num_new_waiters;
73 struct tevent_req **waiters;
76 struct messaging_backend *remote;
79 struct messaging_hdr {
85 /****************************************************************************
86 A useful function for testing the message system.
87 ****************************************************************************/
89 static void ping_message(struct messaging_context *msg_ctx,
95 struct server_id_buf idbuf;
97 DEBUG(1, ("INFO: Received PING message from PID %s [%.*s]\n",
98 server_id_str_buf(src, &idbuf), (int)data->length,
99 data->data ? (char *)data->data : ""));
101 messaging_send(msg_ctx, src, MSG_PONG, data);
104 /****************************************************************************
105 Register/replace a dispatch function for a particular message type.
106 JRA changed Dec 13 2006. Only one message handler now permitted per type.
107 *NOTE*: Dispatch functions must be able to cope with incoming
108 messages on an *odd* byte boundary.
109 ****************************************************************************/
112 struct messaging_context *msg_ctx;
120 /****************************************************************************
121 Send one of the messages for the broadcast.
122 ****************************************************************************/
124 static int traverse_fn(struct db_record *rec, const struct server_id *id,
125 uint32_t msg_flags, void *state)
127 struct msg_all *msg_all = (struct msg_all *)state;
130 /* Don't send if the receiver hasn't registered an interest. */
132 if((msg_flags & msg_all->msg_flag) == 0) {
136 /* If the msg send fails because the pid was not found (i.e. smbd died),
137 * the msg has already been deleted from the messages.tdb.*/
139 status = messaging_send_buf(msg_all->msg_ctx, *id, msg_all->msg_type,
140 (const uint8_t *)msg_all->buf, msg_all->len);
142 if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
143 struct server_id_buf idbuf;
146 * If the pid was not found delete the entry from
150 DEBUG(2, ("pid %s doesn't exist\n",
151 server_id_str_buf(*id, &idbuf)));
153 dbwrap_record_delete(rec);
160 * Send a message to all smbd processes.
162 * It isn't very efficient, but should be OK for the sorts of
163 * applications that use it. When we need efficient broadcast we can add
166 * @param n_sent Set to the number of messages sent. This should be
167 * equal to the number of processes, but be careful for races.
169 * @retval True for success.
171 bool message_send_all(struct messaging_context *msg_ctx,
173 const void *buf, size_t len,
176 struct msg_all msg_all;
178 msg_all.msg_type = msg_type;
179 if (msg_type < 0x100) {
180 msg_all.msg_flag = FLAG_MSG_GENERAL;
181 } else if (msg_type > 0x100 && msg_type < 0x200) {
182 msg_all.msg_flag = FLAG_MSG_NMBD;
183 } else if (msg_type > 0x200 && msg_type < 0x300) {
184 msg_all.msg_flag = FLAG_MSG_PRINT_GENERAL;
185 } else if (msg_type > 0x300 && msg_type < 0x400) {
186 msg_all.msg_flag = FLAG_MSG_SMBD;
187 } else if (msg_type > 0x400 && msg_type < 0x600) {
188 msg_all.msg_flag = FLAG_MSG_WINBIND;
189 } else if (msg_type > 4000 && msg_type < 5000) {
190 msg_all.msg_flag = FLAG_MSG_DBWRAP;
198 msg_all.msg_ctx = msg_ctx;
200 serverid_traverse(traverse_fn, &msg_all);
202 *n_sent = msg_all.n_sent;
206 static void messaging_recv_cb(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 const struct messaging_hdr *hdr;
212 struct server_id_buf idbuf;
213 struct messaging_rec rec;
215 if (msg_len < sizeof(*hdr)) {
216 DEBUG(1, ("message too short: %u\n", (unsigned)msg_len));
221 * messages_dgm guarantees alignment, so we can cast here
223 hdr = (const struct messaging_hdr *)msg;
225 DEBUG(10, ("%s: Received message 0x%x len %u from %s\n", __func__,
226 (unsigned)hdr->msg_type, (unsigned)(msg_len - sizeof(*hdr)),
227 server_id_str_buf(hdr->src, &idbuf)));
229 rec = (struct messaging_rec) {
230 .msg_version = MESSAGE_VERSION,
231 .msg_type = hdr->msg_type,
234 .buf.data = discard_const_p(uint8, msg) + sizeof(*hdr),
235 .buf.length = msg_len - sizeof(*hdr)
238 messaging_dispatch_rec(msg_ctx, &rec);
241 static int messaging_context_destructor(struct messaging_context *ctx)
243 messaging_dgm_destroy();
247 struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx,
248 struct tevent_context *ev)
250 struct messaging_context *ctx;
254 if (!(ctx = talloc_zero(mem_ctx, struct messaging_context))) {
258 ctx->id = procid_self();
263 ret = messaging_dgm_init(ctx->event_ctx, ctx->id,
264 lp_cache_directory(), sec_initial_uid(),
265 messaging_recv_cb, ctx);
268 DEBUG(2, ("messaging_dgm_init failed: %s\n", strerror(ret)));
273 talloc_set_destructor(ctx, messaging_context_destructor);
275 if (lp_clustering()) {
276 status = messaging_ctdbd_init(ctx, ctx, &ctx->remote);
278 if (!NT_STATUS_IS_OK(status)) {
279 DEBUG(2, ("messaging_ctdbd_init failed: %s\n",
285 ctx->id.vnn = get_my_vnn();
287 messaging_register(ctx, NULL, MSG_PING, ping_message);
289 /* Register some debugging related messages */
291 register_msg_pool_usage(ctx);
292 register_dmalloc_msgs(ctx);
293 debug_register_msgs(ctx);
298 struct server_id messaging_server_id(const struct messaging_context *msg_ctx)
304 * re-init after a fork
306 NTSTATUS messaging_reinit(struct messaging_context *msg_ctx)
311 messaging_dgm_destroy();
313 msg_ctx->id = procid_self();
315 ret = messaging_dgm_init(msg_ctx->event_ctx, msg_ctx->id,
316 lp_cache_directory(), sec_initial_uid(),
317 messaging_recv_cb, msg_ctx);
319 DEBUG(0, ("messaging_dgm_init failed: %s\n", strerror(errno)));
320 return map_nt_error_from_unix(ret);
323 TALLOC_FREE(msg_ctx->remote);
325 if (lp_clustering()) {
326 status = messaging_ctdbd_init(msg_ctx, msg_ctx,
329 if (!NT_STATUS_IS_OK(status)) {
330 DEBUG(1, ("messaging_ctdbd_init failed: %s\n",
341 * Register a dispatch function for a particular message type. Allow multiple
344 NTSTATUS messaging_register(struct messaging_context *msg_ctx,
347 void (*fn)(struct messaging_context *msg,
350 struct server_id server_id,
353 struct messaging_callback *cb;
355 DEBUG(5, ("Registering messaging pointer for type %u - "
357 (unsigned)msg_type, private_data));
360 * Only one callback per type
363 for (cb = msg_ctx->callbacks; cb != NULL; cb = cb->next) {
364 /* we allow a second registration of the same message
365 type if it has a different private pointer. This is
366 needed in, for example, the internal notify code,
367 which creates a new notify context for each tree
368 connect, and expects to receive messages to each of
370 if (cb->msg_type == msg_type && private_data == cb->private_data) {
371 DEBUG(5,("Overriding messaging pointer for type %u - private_data=%p\n",
372 (unsigned)msg_type, private_data));
374 cb->private_data = private_data;
379 if (!(cb = talloc(msg_ctx, struct messaging_callback))) {
380 return NT_STATUS_NO_MEMORY;
383 cb->msg_type = msg_type;
385 cb->private_data = private_data;
387 DLIST_ADD(msg_ctx->callbacks, cb);
392 De-register the function for a particular message type.
394 void messaging_deregister(struct messaging_context *ctx, uint32_t msg_type,
397 struct messaging_callback *cb, *next;
399 for (cb = ctx->callbacks; cb; cb = next) {
401 if ((cb->msg_type == msg_type)
402 && (cb->private_data == private_data)) {
403 DEBUG(5,("Deregistering messaging pointer for type %u - private_data=%p\n",
404 (unsigned)msg_type, private_data));
405 DLIST_REMOVE(ctx->callbacks, cb);
412 Send a message to a particular server
414 NTSTATUS messaging_send(struct messaging_context *msg_ctx,
415 struct server_id server, uint32_t msg_type,
416 const DATA_BLOB *data)
420 iov.iov_base = data->data;
421 iov.iov_len = data->length;
423 return messaging_send_iov(msg_ctx, server, msg_type, &iov, 1);
426 NTSTATUS messaging_send_buf(struct messaging_context *msg_ctx,
427 struct server_id server, uint32_t msg_type,
428 const uint8_t *buf, size_t len)
430 DATA_BLOB blob = data_blob_const(buf, len);
431 return messaging_send(msg_ctx, server, msg_type, &blob);
434 NTSTATUS messaging_send_iov(struct messaging_context *msg_ctx,
435 struct server_id server, uint32_t msg_type,
436 const struct iovec *iov, int iovlen)
439 struct messaging_hdr hdr;
440 struct iovec iov2[iovlen+1];
442 if (server_id_is_disconnected(&server)) {
443 return NT_STATUS_INVALID_PARAMETER_MIX;
446 if (!procid_is_local(&server)) {
447 ret = msg_ctx->remote->send_fn(msg_ctx->id, server,
448 msg_type, iov, iovlen,
451 return map_nt_error_from_unix(ret);
456 if (server_id_same_process(&msg_ctx->id, &server)) {
457 struct messaging_rec rec;
461 * Self-send, directly dispatch
464 buf = iov_buf(talloc_tos(), iov, iovlen);
466 return NT_STATUS_NO_MEMORY;
469 rec = (struct messaging_rec) {
470 .msg_version = MESSAGE_VERSION,
471 .msg_type = msg_type & MSG_TYPE_MASK,
474 .buf = data_blob_const(buf, talloc_get_size(buf)),
477 messaging_dispatch_rec(msg_ctx, &rec);
482 hdr = (struct messaging_hdr) {
483 .msg_type = msg_type,
487 iov2[0] = (struct iovec){ .iov_base = &hdr, .iov_len = sizeof(hdr) };
488 memcpy(&iov2[1], iov, iovlen * sizeof(*iov));
491 ret = messaging_dgm_send(server.pid, iov2, iovlen+1);
495 return map_nt_error_from_unix(ret);
500 static struct messaging_rec *messaging_rec_dup(TALLOC_CTX *mem_ctx,
501 struct messaging_rec *rec)
503 struct messaging_rec *result;
505 result = talloc_pooled_object(mem_ctx, struct messaging_rec,
507 if (result == NULL) {
512 /* Doesn't fail, see talloc_pooled_object */
514 result->buf.data = talloc_memdup(result, rec->buf.data,
519 struct messaging_filtered_read_state {
520 struct tevent_context *ev;
521 struct messaging_context *msg_ctx;
524 bool (*filter)(struct messaging_rec *rec, void *private_data);
527 struct messaging_rec *rec;
530 static void messaging_filtered_read_cleanup(struct tevent_req *req,
531 enum tevent_req_state req_state);
533 struct tevent_req *messaging_filtered_read_send(
534 TALLOC_CTX *mem_ctx, struct tevent_context *ev,
535 struct messaging_context *msg_ctx,
536 bool (*filter)(struct messaging_rec *rec, void *private_data),
539 struct tevent_req *req;
540 struct messaging_filtered_read_state *state;
541 size_t new_waiters_len;
543 req = tevent_req_create(mem_ctx, &state,
544 struct messaging_filtered_read_state);
549 state->msg_ctx = msg_ctx;
550 state->filter = filter;
551 state->private_data = private_data;
554 * We have to defer the callback here, as we might be called from
555 * within a different tevent_context than state->ev
557 tevent_req_defer_callback(req, state->ev);
559 state->tevent_handle = messaging_dgm_register_tevent_context(
561 if (tevent_req_nomem(state, req)) {
562 return tevent_req_post(req, ev);
566 * We add ourselves to the "new_waiters" array, not the "waiters"
567 * array. If we are called from within messaging_read_done,
568 * messaging_dispatch_rec will be in an active for-loop on
569 * "waiters". We must be careful not to mess with this array, because
570 * it could mean that a single event is being delivered twice.
573 new_waiters_len = talloc_array_length(msg_ctx->new_waiters);
575 if (new_waiters_len == msg_ctx->num_new_waiters) {
576 struct tevent_req **tmp;
578 tmp = talloc_realloc(msg_ctx, msg_ctx->new_waiters,
579 struct tevent_req *, new_waiters_len+1);
580 if (tevent_req_nomem(tmp, req)) {
581 return tevent_req_post(req, ev);
583 msg_ctx->new_waiters = tmp;
586 msg_ctx->new_waiters[msg_ctx->num_new_waiters] = req;
587 msg_ctx->num_new_waiters += 1;
588 tevent_req_set_cleanup_fn(req, messaging_filtered_read_cleanup);
593 static void messaging_filtered_read_cleanup(struct tevent_req *req,
594 enum tevent_req_state req_state)
596 struct messaging_filtered_read_state *state = tevent_req_data(
597 req, struct messaging_filtered_read_state);
598 struct messaging_context *msg_ctx = state->msg_ctx;
601 tevent_req_set_cleanup_fn(req, NULL);
603 TALLOC_FREE(state->tevent_handle);
606 * Just set the [new_]waiters entry to NULL, be careful not to mess
607 * with the other "waiters" array contents. We are often called from
608 * within "messaging_dispatch_rec", which loops over
609 * "waiters". Messing with the "waiters" array will mess up that
613 for (i=0; i<msg_ctx->num_waiters; i++) {
614 if (msg_ctx->waiters[i] == req) {
615 msg_ctx->waiters[i] = NULL;
620 for (i=0; i<msg_ctx->num_new_waiters; i++) {
621 if (msg_ctx->new_waiters[i] == req) {
622 msg_ctx->new_waiters[i] = NULL;
628 static void messaging_filtered_read_done(struct tevent_req *req,
629 struct messaging_rec *rec)
631 struct messaging_filtered_read_state *state = tevent_req_data(
632 req, struct messaging_filtered_read_state);
634 state->rec = messaging_rec_dup(state, rec);
635 if (tevent_req_nomem(state->rec, req)) {
638 tevent_req_done(req);
641 int messaging_filtered_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
642 struct messaging_rec **presult)
644 struct messaging_filtered_read_state *state = tevent_req_data(
645 req, struct messaging_filtered_read_state);
648 if (tevent_req_is_unix_error(req, &err)) {
649 tevent_req_received(req);
652 *presult = talloc_move(mem_ctx, &state->rec);
656 struct messaging_read_state {
658 struct messaging_rec *rec;
661 static bool messaging_read_filter(struct messaging_rec *rec,
663 static void messaging_read_done(struct tevent_req *subreq);
665 struct tevent_req *messaging_read_send(TALLOC_CTX *mem_ctx,
666 struct tevent_context *ev,
667 struct messaging_context *msg,
670 struct tevent_req *req, *subreq;
671 struct messaging_read_state *state;
673 req = tevent_req_create(mem_ctx, &state,
674 struct messaging_read_state);
678 state->msg_type = msg_type;
680 subreq = messaging_filtered_read_send(state, ev, msg,
681 messaging_read_filter, state);
682 if (tevent_req_nomem(subreq, req)) {
683 return tevent_req_post(req, ev);
685 tevent_req_set_callback(subreq, messaging_read_done, req);
689 static bool messaging_read_filter(struct messaging_rec *rec,
692 struct messaging_read_state *state = talloc_get_type_abort(
693 private_data, struct messaging_read_state);
695 return rec->msg_type == state->msg_type;
698 static void messaging_read_done(struct tevent_req *subreq)
700 struct tevent_req *req = tevent_req_callback_data(
701 subreq, struct tevent_req);
702 struct messaging_read_state *state = tevent_req_data(
703 req, struct messaging_read_state);
706 ret = messaging_filtered_read_recv(subreq, state, &state->rec);
708 if (tevent_req_error(req, ret)) {
711 tevent_req_done(req);
714 int messaging_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
715 struct messaging_rec **presult)
717 struct messaging_read_state *state = tevent_req_data(
718 req, struct messaging_read_state);
721 if (tevent_req_is_unix_error(req, &err)) {
724 if (presult != NULL) {
725 *presult = talloc_move(mem_ctx, &state->rec);
730 static bool messaging_append_new_waiters(struct messaging_context *msg_ctx)
732 if (msg_ctx->num_new_waiters == 0) {
736 if (talloc_array_length(msg_ctx->waiters) <
737 (msg_ctx->num_waiters + msg_ctx->num_new_waiters)) {
738 struct tevent_req **tmp;
739 tmp = talloc_realloc(
740 msg_ctx, msg_ctx->waiters, struct tevent_req *,
741 msg_ctx->num_waiters + msg_ctx->num_new_waiters);
743 DEBUG(1, ("%s: talloc failed\n", __func__));
746 msg_ctx->waiters = tmp;
749 memcpy(&msg_ctx->waiters[msg_ctx->num_waiters], msg_ctx->new_waiters,
750 sizeof(struct tevent_req *) * msg_ctx->num_new_waiters);
752 msg_ctx->num_waiters += msg_ctx->num_new_waiters;
753 msg_ctx->num_new_waiters = 0;
758 struct messaging_defer_callback_state {
759 struct messaging_context *msg_ctx;
760 struct messaging_rec *rec;
761 void (*fn)(struct messaging_context *msg, void *private_data,
762 uint32_t msg_type, struct server_id server_id,
767 static void messaging_defer_callback_trigger(struct tevent_context *ev,
768 struct tevent_immediate *im,
771 static void messaging_defer_callback(
772 struct messaging_context *msg_ctx, struct messaging_rec *rec,
773 void (*fn)(struct messaging_context *msg, void *private_data,
774 uint32_t msg_type, struct server_id server_id,
778 struct messaging_defer_callback_state *state;
779 struct tevent_immediate *im;
781 state = talloc(msg_ctx, struct messaging_defer_callback_state);
783 DEBUG(1, ("talloc failed\n"));
786 state->msg_ctx = msg_ctx;
788 state->private_data = private_data;
790 state->rec = messaging_rec_dup(state, rec);
791 if (state->rec == NULL) {
792 DEBUG(1, ("talloc failed\n"));
797 im = tevent_create_immediate(state);
799 DEBUG(1, ("tevent_create_immediate failed\n"));
803 tevent_schedule_immediate(im, msg_ctx->event_ctx,
804 messaging_defer_callback_trigger, state);
807 static void messaging_defer_callback_trigger(struct tevent_context *ev,
808 struct tevent_immediate *im,
811 struct messaging_defer_callback_state *state = talloc_get_type_abort(
812 private_data, struct messaging_defer_callback_state);
813 struct messaging_rec *rec = state->rec;
815 state->fn(state->msg_ctx, state->private_data, rec->msg_type, rec->src,
821 Dispatch one messaging_rec
823 void messaging_dispatch_rec(struct messaging_context *msg_ctx,
824 struct messaging_rec *rec)
826 struct messaging_callback *cb, *next;
829 for (cb = msg_ctx->callbacks; cb != NULL; cb = next) {
831 if (cb->msg_type != rec->msg_type) {
835 if (server_id_same_process(&rec->src, &rec->dest)) {
837 * This is a self-send. We are called here from
838 * messaging_send(), and we don't want to directly
839 * recurse into the callback but go via a
842 messaging_defer_callback(msg_ctx, rec, cb->fn,
846 * This comes from a different process. we are called
847 * from the event loop, so we should call back
850 cb->fn(msg_ctx, cb->private_data, rec->msg_type,
851 rec->src, &rec->buf);
854 * we continue looking for matching messages after finding
855 * one. This matters for subsystems like the internal notify
856 * code which register more than one handler for the same
861 if (!messaging_append_new_waiters(msg_ctx)) {
866 while (i < msg_ctx->num_waiters) {
867 struct tevent_req *req;
868 struct messaging_filtered_read_state *state;
870 req = msg_ctx->waiters[i];
873 * This got cleaned up. In the meantime,
874 * move everything down one. We need
875 * to keep the order of waiters, as
876 * other code may depend on this.
878 if (i < msg_ctx->num_waiters - 1) {
879 memmove(&msg_ctx->waiters[i],
880 &msg_ctx->waiters[i+1],
881 sizeof(struct tevent_req *) *
882 (msg_ctx->num_waiters - i - 1));
884 msg_ctx->num_waiters -= 1;
888 state = tevent_req_data(
889 req, struct messaging_filtered_read_state);
890 if (state->filter(rec, state->private_data)) {
891 messaging_filtered_read_done(req, rec);
898 static int mess_parent_dgm_cleanup(void *private_data);
899 static void mess_parent_dgm_cleanup_done(struct tevent_req *req);
901 bool messaging_parent_dgm_cleanup_init(struct messaging_context *msg)
903 struct tevent_req *req;
905 req = background_job_send(
906 msg, msg->event_ctx, msg, NULL, 0,
907 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
909 mess_parent_dgm_cleanup, msg);
913 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
917 static int mess_parent_dgm_cleanup(void *private_data)
921 ret = messaging_dgm_wipe();
922 DEBUG(10, ("messaging_dgm_wipe returned %s\n",
923 ret ? strerror(ret) : "ok"));
924 return lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
928 static void mess_parent_dgm_cleanup_done(struct tevent_req *req)
930 struct messaging_context *msg = tevent_req_callback_data(
931 req, struct messaging_context);
934 status = background_job_recv(req);
936 DEBUG(1, ("messaging dgm cleanup job ended with %s\n",
939 req = background_job_send(
940 msg, msg->event_ctx, msg, NULL, 0,
941 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
943 mess_parent_dgm_cleanup, msg);
945 DEBUG(1, ("background_job_send failed\n"));
947 tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
950 int messaging_cleanup(struct messaging_context *msg_ctx, pid_t pid)
955 ret = messaging_dgm_wipe();
957 ret = messaging_dgm_cleanup(pid);
963 struct tevent_context *messaging_tevent_context(
964 struct messaging_context *msg_ctx)
966 return msg_ctx->event_ctx;