2 Unix SMB/CIFS implementation.
3 Samba internal messaging functions
4 Copyright (C) 2007 by Volker Lendecke
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
21 @defgroup messages Internal messaging framework
25 @brief Module for internal messaging between Samba daemons.
27 The idea is that if a part of Samba wants to do communication with
28 another Samba process then it will do a message_register() of a
29 dispatch function, and use message_send_pid() to send messages to
32 The dispatch function is given the pid of the sender, and it can
33 use that to reply by message_send_pid(). See ping_message() for a
36 @caution Dispatch functions must be able to cope with incoming
37 messages on an *odd* byte boundary.
39 This system doesn't have any inherent size limitations but is not
40 very efficient for large messages or when messages are sent in very
46 #include "system/filesys.h"
49 #include "lib/tdb_wrap/tdb_wrap.h"
50 #include "lib/param/param.h"
52 struct messaging_tdb_context {
53 struct messaging_context *msg_ctx;
55 struct tevent_signal *se;
56 int received_messages;
60 static NTSTATUS messaging_tdb_send(struct messaging_context *msg_ctx,
61 struct server_id pid, int msg_type,
62 const DATA_BLOB *data,
63 struct messaging_backend *backend);
64 static void message_dispatch(struct messaging_context *msg_ctx);
66 static void messaging_tdb_signal_handler(struct tevent_context *ev_ctx,
67 struct tevent_signal *se,
68 int signum, int count,
69 void *_info, void *private_data)
71 struct messaging_tdb_context *ctx = talloc_get_type(private_data,
72 struct messaging_tdb_context);
74 ctx->received_messages++;
76 DEBUG(10, ("messaging_tdb_signal_handler: sig[%d] count[%d] msgs[%d]\n",
77 signum, count, ctx->received_messages));
79 message_dispatch(ctx->msg_ctx);
82 static int messaging_tdb_context_destructor(struct messaging_tdb_context *ctx);
84 /****************************************************************************
85 Initialise the messaging functions.
86 ****************************************************************************/
88 NTSTATUS messaging_tdb_init(struct messaging_context *msg_ctx,
90 struct messaging_backend **presult)
92 struct messaging_backend *result;
93 struct messaging_tdb_context *ctx;
94 struct loadparm_context *lp_ctx;
95 static bool have_context = false;
99 DEBUG(0, ("No two messaging contexts per process\n"));
100 return NT_STATUS_OBJECT_NAME_COLLISION;
103 if (!(result = talloc(mem_ctx, struct messaging_backend))) {
104 DEBUG(0, ("talloc failed\n"));
105 return NT_STATUS_NO_MEMORY;
108 lp_ctx = loadparm_init_s3(result, loadparm_s3_helpers());
109 if (lp_ctx == NULL) {
110 DEBUG(0, ("loadparm_init_s3 failed\n"));
112 return NT_STATUS_INTERNAL_ERROR;
115 ctx = talloc_zero(result, struct messaging_tdb_context);
117 DEBUG(0, ("talloc failed\n"));
119 return NT_STATUS_NO_MEMORY;
121 result->private_data = ctx;
122 result->send_fn = messaging_tdb_send;
124 ctx->msg_ctx = msg_ctx;
125 ctx->have_context = &have_context;
127 fname = lock_path("messages.tdb");
129 ctx->tdb = tdb_wrap_open(
130 ctx, fname, lpcfg_tdb_hash_size(lp_ctx, fname),
131 lpcfg_tdb_flags(lp_ctx, TDB_CLEAR_IF_FIRST|TDB_DEFAULT|
132 TDB_VOLATILE| TDB_INCOMPATIBLE_HASH),
133 O_RDWR|O_CREAT,0600);
135 talloc_unlink(result, lp_ctx);
138 NTSTATUS status = map_nt_error_from_unix(errno);
139 DEBUG(2, ("ERROR: Failed to initialise messages database: "
140 "%s\n", strerror(errno)));
145 ctx->se = tevent_add_signal(msg_ctx->event_ctx,
148 messaging_tdb_signal_handler,
151 NTSTATUS status = map_nt_error_from_unix(errno);
152 DEBUG(0, ("ERROR: Failed to initialise messages signal handler: "
153 "%s\n", strerror(errno)));
161 talloc_set_destructor(ctx, messaging_tdb_context_destructor);
167 static int messaging_tdb_context_destructor(struct messaging_tdb_context *ctx)
169 SMB_ASSERT(*ctx->have_context);
170 *ctx->have_context = false;
174 bool messaging_tdb_parent_init(TALLOC_CTX *mem_ctx)
177 struct loadparm_context *lp_ctx;
180 lp_ctx = loadparm_init_s3(mem_ctx, loadparm_s3_helpers());
181 if (lp_ctx == NULL) {
182 DEBUG(0, ("loadparm_init_s3 failed\n"));
187 * Open the tdb in the parent process (smbd) so that our
188 * CLEAR_IF_FIRST optimization in tdb_reopen_all can properly
192 fname = lock_path("messages.tdb");
194 mem_ctx, fname, lpcfg_tdb_hash_size(lp_ctx, fname),
195 lpcfg_tdb_flags(lp_ctx, TDB_CLEAR_IF_FIRST|TDB_DEFAULT|
196 TDB_VOLATILE|TDB_INCOMPATIBLE_HASH),
197 O_RDWR|O_CREAT,0600);
198 talloc_unlink(mem_ctx, lp_ctx);
200 DEBUG(1, ("could not open messaging.tdb: %s\n",
207 /*******************************************************************
208 Form a static tdb key from a pid.
209 ******************************************************************/
211 static TDB_DATA message_key_pid(TALLOC_CTX *mem_ctx, struct server_id pid)
216 key = talloc_asprintf(mem_ctx, "PID/%s", procid_str_static(&pid));
218 SMB_ASSERT(key != NULL);
220 kbuf.dptr = (uint8 *)key;
221 kbuf.dsize = strlen(key)+1;
225 /*******************************************************************
226 Called when a process has terminated abnormally. Remove all messages
228 ******************************************************************/
230 NTSTATUS messaging_tdb_cleanup(struct messaging_context *msg_ctx,
231 struct server_id pid)
233 struct messaging_tdb_context *ctx = talloc_get_type(
234 msg_ctx->local->private_data,
235 struct messaging_tdb_context);
236 struct tdb_wrap *tdb = ctx->tdb;
238 TALLOC_CTX *frame = talloc_stackframe();
240 key = message_key_pid(frame, pid);
242 * We have to lock the key to avoid
243 * races in case the server_id was
244 * re-used and is active (a remote
245 * possibility, true). We only
246 * clean up the database if we
247 * know server_id doesn't exist
248 * while checked under the chainlock.
250 if (tdb_chainlock(tdb->tdb, key) != 0) {
252 return NT_STATUS_LOCK_NOT_GRANTED;
254 if (!serverid_exists(&pid)) {
255 (void)tdb_delete(tdb->tdb, key);
257 tdb_chainunlock(tdb->tdb, key);
263 Fetch the messaging array for a process
266 static NTSTATUS messaging_tdb_fetch(TDB_CONTEXT *msg_tdb,
269 struct messaging_array **presult)
271 struct messaging_array *result;
274 enum ndr_err_code ndr_err;
276 if (!(result = talloc_zero(mem_ctx, struct messaging_array))) {
277 return NT_STATUS_NO_MEMORY;
280 data = tdb_fetch(msg_tdb, key);
282 if (data.dptr == NULL) {
287 blob = data_blob_const(data.dptr, data.dsize);
289 ndr_err = ndr_pull_struct_blob_all(
290 &blob, result, result,
291 (ndr_pull_flags_fn_t)ndr_pull_messaging_array);
293 SAFE_FREE(data.dptr);
295 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
297 return ndr_map_error2ntstatus(ndr_err);
300 if (DEBUGLEVEL >= 10) {
301 DEBUG(10, ("messaging_tdb_fetch:\n"));
302 NDR_PRINT_DEBUG(messaging_array, result);
310 Store a messaging array for a pid
313 static NTSTATUS messaging_tdb_store(TDB_CONTEXT *msg_tdb,
315 struct messaging_array *array)
319 enum ndr_err_code ndr_err;
323 if (array->num_messages == 0) {
324 tdb_delete(msg_tdb, key);
328 if (!(mem_ctx = talloc_new(array))) {
329 return NT_STATUS_NO_MEMORY;
332 ndr_err = ndr_push_struct_blob(&blob, mem_ctx, array,
333 (ndr_push_flags_fn_t)ndr_push_messaging_array);
335 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
336 talloc_free(mem_ctx);
337 return ndr_map_error2ntstatus(ndr_err);
340 if (DEBUGLEVEL >= 10) {
341 DEBUG(10, ("messaging_tdb_store:\n"));
342 NDR_PRINT_DEBUG(messaging_array, array);
345 data.dptr = blob.data;
346 data.dsize = blob.length;
348 ret = tdb_store(msg_tdb, key, data, TDB_REPLACE);
349 TALLOC_FREE(mem_ctx);
351 return (ret == 0) ? NT_STATUS_OK : NT_STATUS_INTERNAL_DB_CORRUPTION;
354 /****************************************************************************
355 Notify a process that it has a message. If the process doesn't exist
356 then delete its record in the database.
357 ****************************************************************************/
359 static NTSTATUS message_notify(struct server_id procid)
361 pid_t pid = procid.pid;
363 uid_t euid = geteuid();
366 * Doing kill with a non-positive pid causes messages to be
367 * sent to places we don't want.
372 return NT_STATUS_INVALID_HANDLE;
376 /* If we're not root become so to send the message. */
378 set_effective_uid(0);
381 ret = kill(pid, SIGUSR1);
384 /* Go back to who we were. */
385 int saved_errno = errno;
386 restore_re_uid_fromroot();
395 * Something has gone wrong
398 DEBUG(2,("message to process %d failed - %s\n", (int)pid,
402 * No call to map_nt_error_from_unix -- don't want to link in
403 * errormap.o into lots of utils.
406 if (errno == ESRCH) return NT_STATUS_INVALID_HANDLE;
407 if (errno == EINVAL) return NT_STATUS_INVALID_PARAMETER;
408 if (errno == EPERM) return NT_STATUS_ACCESS_DENIED;
409 return NT_STATUS_UNSUCCESSFUL;
412 /****************************************************************************
413 Send a message to a particular pid.
414 ****************************************************************************/
416 static NTSTATUS messaging_tdb_send(struct messaging_context *msg_ctx,
417 struct server_id pid, int msg_type,
418 const DATA_BLOB *data,
419 struct messaging_backend *backend)
421 struct messaging_tdb_context *ctx = talloc_get_type(backend->private_data,
422 struct messaging_tdb_context);
423 struct messaging_array *msg_array;
424 struct messaging_rec *rec;
427 struct tdb_wrap *tdb = ctx->tdb;
428 TALLOC_CTX *frame = talloc_stackframe();
430 /* NULL pointer means implicit length zero. */
432 SMB_ASSERT(data->length == 0);
436 * Doing kill with a non-positive pid causes messages to be
437 * sent to places we don't want.
440 SMB_ASSERT(procid_to_pid(&pid) > 0);
442 key = message_key_pid(frame, pid);
444 if (tdb_chainlock(tdb->tdb, key) != 0) {
446 return NT_STATUS_LOCK_NOT_GRANTED;
449 status = messaging_tdb_fetch(tdb->tdb, key, frame, &msg_array);
451 if (!NT_STATUS_IS_OK(status)) {
455 if ((msg_type & MSG_FLAG_LOWPRIORITY)
456 && (msg_array->num_messages > 1000)) {
457 DEBUG(5, ("Dropping message for PID %s\n",
458 procid_str_static(&pid)));
459 status = NT_STATUS_INSUFFICIENT_RESOURCES;
463 if (!(rec = talloc_realloc(frame, msg_array->messages,
464 struct messaging_rec,
465 msg_array->num_messages+1))) {
466 status = NT_STATUS_NO_MEMORY;
470 rec[msg_array->num_messages].msg_version = MESSAGE_VERSION;
471 rec[msg_array->num_messages].msg_type = msg_type & MSG_TYPE_MASK;
472 rec[msg_array->num_messages].dest = pid;
473 rec[msg_array->num_messages].src = msg_ctx->id;
474 rec[msg_array->num_messages].buf = *data;
476 msg_array->messages = rec;
477 msg_array->num_messages += 1;
479 status = messaging_tdb_store(tdb->tdb, key, msg_array);
481 if (!NT_STATUS_IS_OK(status)) {
485 status = message_notify(pid);
487 if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
488 DEBUG(2, ("pid %s doesn't exist - deleting messages record\n",
489 procid_str_static(&pid)));
490 tdb_delete(tdb->tdb, message_key_pid(frame, pid));
494 tdb_chainunlock(tdb->tdb, key);
499 /****************************************************************************
500 Retrieve all messages for a process.
501 ****************************************************************************/
503 static NTSTATUS retrieve_all_messages(TDB_CONTEXT *msg_tdb,
506 struct messaging_array **presult)
508 struct messaging_array *result;
509 TDB_DATA key = message_key_pid(mem_ctx, id);
512 if (tdb_chainlock(msg_tdb, key) != 0) {
513 TALLOC_FREE(key.dptr);
514 return NT_STATUS_LOCK_NOT_GRANTED;
517 status = messaging_tdb_fetch(msg_tdb, key, mem_ctx, &result);
520 * We delete the record here, tdb_set_max_dead keeps it around
522 tdb_delete(msg_tdb, key);
523 tdb_chainunlock(msg_tdb, key);
525 if (NT_STATUS_IS_OK(status)) {
529 TALLOC_FREE(key.dptr);
534 /****************************************************************************
535 Receive and dispatch any messages pending for this process.
536 JRA changed Dec 13 2006. Only one message handler now permitted per type.
537 *NOTE*: Dispatch functions must be able to cope with incoming
538 messages on an *odd* byte boundary.
539 ****************************************************************************/
541 static void message_dispatch(struct messaging_context *msg_ctx)
543 struct messaging_tdb_context *ctx = talloc_get_type(msg_ctx->local->private_data,
544 struct messaging_tdb_context);
545 struct messaging_array *msg_array = NULL;
546 struct tdb_wrap *tdb = ctx->tdb;
550 if (ctx->received_messages == 0) {
554 DEBUG(10, ("message_dispatch: received_messages = %d\n",
555 ctx->received_messages));
557 status = retrieve_all_messages(tdb->tdb, msg_ctx->id, NULL, &msg_array);
558 if (!NT_STATUS_IS_OK(status)) {
559 DEBUG(0, ("message_dispatch: failed to retrieve messages: %s\n",
564 ctx->received_messages = 0;
566 for (i=0; i<msg_array->num_messages; i++) {
567 messaging_dispatch_rec(msg_ctx, &msg_array->messages[i]);
570 TALLOC_FREE(msg_array);