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"
48 #include "lib/util/tdb_wrap.h"
50 struct messaging_tdb_context {
51 struct messaging_context *msg_ctx;
53 struct tevent_signal *se;
54 int received_messages;
57 static NTSTATUS messaging_tdb_send(struct messaging_context *msg_ctx,
58 struct server_id pid, int msg_type,
59 const DATA_BLOB *data,
60 struct messaging_backend *backend);
61 static void message_dispatch(struct messaging_context *msg_ctx);
63 static void messaging_tdb_signal_handler(struct tevent_context *ev_ctx,
64 struct tevent_signal *se,
65 int signum, int count,
66 void *_info, void *private_data)
68 struct messaging_tdb_context *ctx = talloc_get_type(private_data,
69 struct messaging_tdb_context);
71 ctx->received_messages++;
73 DEBUG(10, ("messaging_tdb_signal_handler: sig[%d] count[%d] msgs[%d]\n",
74 signum, count, ctx->received_messages));
76 message_dispatch(ctx->msg_ctx);
79 /****************************************************************************
80 Initialise the messaging functions.
81 ****************************************************************************/
83 NTSTATUS messaging_tdb_init(struct messaging_context *msg_ctx,
85 struct messaging_backend **presult)
87 struct messaging_backend *result;
88 struct messaging_tdb_context *ctx;
90 if (!(result = TALLOC_P(mem_ctx, struct messaging_backend))) {
91 DEBUG(0, ("talloc failed\n"));
92 return NT_STATUS_NO_MEMORY;
95 ctx = TALLOC_ZERO_P(result, struct messaging_tdb_context);
97 DEBUG(0, ("talloc failed\n"));
99 return NT_STATUS_NO_MEMORY;
101 result->private_data = ctx;
102 result->send_fn = messaging_tdb_send;
104 ctx->msg_ctx = msg_ctx;
106 ctx->tdb = tdb_wrap_open(ctx, lock_path("messages.tdb"), 0,
107 TDB_CLEAR_IF_FIRST|TDB_DEFAULT|TDB_VOLATILE|TDB_INCOMPATIBLE_HASH,
108 O_RDWR|O_CREAT,0600);
111 NTSTATUS status = map_nt_error_from_unix(errno);
112 DEBUG(2, ("ERROR: Failed to initialise messages database: "
113 "%s\n", strerror(errno)));
118 ctx->se = tevent_add_signal(msg_ctx->event_ctx,
121 messaging_tdb_signal_handler,
124 NTSTATUS status = map_nt_error_from_unix(errno);
125 DEBUG(0, ("ERROR: Failed to initialise messages signal handler: "
126 "%s\n", strerror(errno)));
137 bool messaging_tdb_parent_init(TALLOC_CTX *mem_ctx)
142 * Open the tdb in the parent process (smbd) so that our
143 * CLEAR_IF_FIRST optimization in tdb_reopen_all can properly
147 db = tdb_wrap_open(mem_ctx, lock_path("messages.tdb"), 0,
148 TDB_CLEAR_IF_FIRST|TDB_DEFAULT|TDB_VOLATILE|TDB_INCOMPATIBLE_HASH,
149 O_RDWR|O_CREAT,0600);
151 DEBUG(1, ("could not open messaging.tdb: %s\n",
158 /*******************************************************************
159 Form a static tdb key from a pid.
160 ******************************************************************/
162 static TDB_DATA message_key_pid(TALLOC_CTX *mem_ctx, struct server_id pid)
167 key = talloc_asprintf(talloc_tos(), "PID/%s", procid_str_static(&pid));
169 SMB_ASSERT(key != NULL);
171 kbuf.dptr = (uint8 *)key;
172 kbuf.dsize = strlen(key)+1;
177 Fetch the messaging array for a process
180 static NTSTATUS messaging_tdb_fetch(TDB_CONTEXT *msg_tdb,
183 struct messaging_array **presult)
185 struct messaging_array *result;
188 enum ndr_err_code ndr_err;
190 if (!(result = TALLOC_ZERO_P(mem_ctx, struct messaging_array))) {
191 return NT_STATUS_NO_MEMORY;
194 data = tdb_fetch(msg_tdb, key);
196 if (data.dptr == NULL) {
201 blob = data_blob_const(data.dptr, data.dsize);
203 ndr_err = ndr_pull_struct_blob(
204 &blob, result, result,
205 (ndr_pull_flags_fn_t)ndr_pull_messaging_array);
207 SAFE_FREE(data.dptr);
209 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
211 return ndr_map_error2ntstatus(ndr_err);
214 if (DEBUGLEVEL >= 10) {
215 DEBUG(10, ("messaging_tdb_fetch:\n"));
216 NDR_PRINT_DEBUG(messaging_array, result);
224 Store a messaging array for a pid
227 static NTSTATUS messaging_tdb_store(TDB_CONTEXT *msg_tdb,
229 struct messaging_array *array)
233 enum ndr_err_code ndr_err;
237 if (array->num_messages == 0) {
238 tdb_delete(msg_tdb, key);
242 if (!(mem_ctx = talloc_new(array))) {
243 return NT_STATUS_NO_MEMORY;
246 ndr_err = ndr_push_struct_blob(&blob, mem_ctx, array,
247 (ndr_push_flags_fn_t)ndr_push_messaging_array);
249 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
250 talloc_free(mem_ctx);
251 return ndr_map_error2ntstatus(ndr_err);
254 if (DEBUGLEVEL >= 10) {
255 DEBUG(10, ("messaging_tdb_store:\n"));
256 NDR_PRINT_DEBUG(messaging_array, array);
259 data.dptr = blob.data;
260 data.dsize = blob.length;
262 ret = tdb_store(msg_tdb, key, data, TDB_REPLACE);
263 TALLOC_FREE(mem_ctx);
265 return (ret == 0) ? NT_STATUS_OK : NT_STATUS_INTERNAL_DB_CORRUPTION;
268 /****************************************************************************
269 Notify a process that it has a message. If the process doesn't exist
270 then delete its record in the database.
271 ****************************************************************************/
273 static NTSTATUS message_notify(struct server_id procid)
275 pid_t pid = procid.pid;
277 uid_t euid = geteuid();
280 * Doing kill with a non-positive pid causes messages to be
281 * sent to places we don't want.
287 /* If we're not root become so to send the message. */
289 set_effective_uid(0);
292 ret = kill(pid, SIGUSR1);
295 /* Go back to who we were. */
296 int saved_errno = errno;
297 restore_re_uid_fromroot();
306 * Something has gone wrong
309 DEBUG(2,("message to process %d failed - %s\n", (int)pid,
313 * No call to map_nt_error_from_unix -- don't want to link in
314 * errormap.o into lots of utils.
317 if (errno == ESRCH) return NT_STATUS_INVALID_HANDLE;
318 if (errno == EINVAL) return NT_STATUS_INVALID_PARAMETER;
319 if (errno == EPERM) return NT_STATUS_ACCESS_DENIED;
320 return NT_STATUS_UNSUCCESSFUL;
323 /****************************************************************************
324 Send a message to a particular pid.
325 ****************************************************************************/
327 static NTSTATUS messaging_tdb_send(struct messaging_context *msg_ctx,
328 struct server_id pid, int msg_type,
329 const DATA_BLOB *data,
330 struct messaging_backend *backend)
332 struct messaging_tdb_context *ctx = talloc_get_type(backend->private_data,
333 struct messaging_tdb_context);
334 struct messaging_array *msg_array;
335 struct messaging_rec *rec;
338 struct tdb_wrap *tdb = ctx->tdb;
339 TALLOC_CTX *frame = talloc_stackframe();
341 /* NULL pointer means implicit length zero. */
343 SMB_ASSERT(data->length == 0);
347 * Doing kill with a non-positive pid causes messages to be
348 * sent to places we don't want.
351 SMB_ASSERT(procid_to_pid(&pid) > 0);
353 key = message_key_pid(frame, pid);
355 if (tdb_chainlock(tdb->tdb, key) == -1) {
357 return NT_STATUS_LOCK_NOT_GRANTED;
360 status = messaging_tdb_fetch(tdb->tdb, key, talloc_tos(), &msg_array);
362 if (!NT_STATUS_IS_OK(status)) {
366 if ((msg_type & MSG_FLAG_LOWPRIORITY)
367 && (msg_array->num_messages > 1000)) {
368 DEBUG(5, ("Dropping message for PID %s\n",
369 procid_str_static(&pid)));
370 status = NT_STATUS_INSUFFICIENT_RESOURCES;
374 if (!(rec = TALLOC_REALLOC_ARRAY(talloc_tos(), msg_array->messages,
375 struct messaging_rec,
376 msg_array->num_messages+1))) {
377 status = NT_STATUS_NO_MEMORY;
381 rec[msg_array->num_messages].msg_version = MESSAGE_VERSION;
382 rec[msg_array->num_messages].msg_type = msg_type & MSG_TYPE_MASK;
383 rec[msg_array->num_messages].dest = pid;
384 rec[msg_array->num_messages].src = msg_ctx->id;
385 rec[msg_array->num_messages].buf = *data;
387 msg_array->messages = rec;
388 msg_array->num_messages += 1;
390 status = messaging_tdb_store(tdb->tdb, key, msg_array);
392 if (!NT_STATUS_IS_OK(status)) {
396 status = message_notify(pid);
398 if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
399 DEBUG(2, ("pid %s doesn't exist - deleting messages record\n",
400 procid_str_static(&pid)));
401 tdb_delete(tdb->tdb, message_key_pid(talloc_tos(), pid));
405 tdb_chainunlock(tdb->tdb, key);
410 /****************************************************************************
411 Retrieve all messages for a process.
412 ****************************************************************************/
414 static NTSTATUS retrieve_all_messages(TDB_CONTEXT *msg_tdb,
417 struct messaging_array **presult)
419 struct messaging_array *result;
420 TDB_DATA key = message_key_pid(mem_ctx, id);
423 if (tdb_chainlock(msg_tdb, key) == -1) {
424 TALLOC_FREE(key.dptr);
425 return NT_STATUS_LOCK_NOT_GRANTED;
428 status = messaging_tdb_fetch(msg_tdb, key, mem_ctx, &result);
431 * We delete the record here, tdb_set_max_dead keeps it around
433 tdb_delete(msg_tdb, key);
434 tdb_chainunlock(msg_tdb, key);
436 if (NT_STATUS_IS_OK(status)) {
440 TALLOC_FREE(key.dptr);
445 /****************************************************************************
446 Receive and dispatch any messages pending for this process.
447 JRA changed Dec 13 2006. Only one message handler now permitted per type.
448 *NOTE*: Dispatch functions must be able to cope with incoming
449 messages on an *odd* byte boundary.
450 ****************************************************************************/
452 static void message_dispatch(struct messaging_context *msg_ctx)
454 struct messaging_tdb_context *ctx = talloc_get_type(msg_ctx->local->private_data,
455 struct messaging_tdb_context);
456 struct messaging_array *msg_array = NULL;
457 struct tdb_wrap *tdb = ctx->tdb;
461 if (ctx->received_messages == 0) {
465 DEBUG(10, ("message_dispatch: received_messages = %d\n",
466 ctx->received_messages));
468 status = retrieve_all_messages(tdb->tdb, msg_ctx->id, NULL, &msg_array);
469 if (!NT_STATUS_IS_OK(status)) {
470 DEBUG(0, ("message_dispatch: failed to retrieve messages: %s\n",
475 ctx->received_messages = 0;
477 for (i=0; i<msg_array->num_messages; i++) {
478 messaging_dispatch_rec(msg_ctx, &msg_array->messages[i]);
481 TALLOC_FREE(msg_array);