source3/lib/messages.c

   1 /*
   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
   8
   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.
  13
  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.
  18
  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/>.
  21 */
  22
  23 /**
  24   @defgroup messages Internal messaging framework
  25   @{
  26   @file messages.c
  27
  28   @brief  Module for internal messaging between Samba daemons.
  29
  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
  33    that process.
  34
  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
  37    simple example.
  38
  39    @caution Dispatch functions must be able to cope with incoming
  40    messages on an *odd* byte boundary.
  41
  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
  44    quick succession.
  45
  46 */
  47
  48 #include "includes.h"
  49 #include "dbwrap/dbwrap.h"
  50 #include "serverid.h"
  51 #include "messages.h"
  52 #include "lib/util/tevent_unix.h"
  53 #include "lib/background.h"
  54 #include "lib/messages_dgm.h"
  55 #include "lib/iov_buf.h"
  56 #include "lib/util/server_id_db.h"
  57
  58 struct messaging_callback {
  59         struct messaging_callback *prev, *next;
  60         uint32 msg_type;
  61         void (*fn)(struct messaging_context *msg, void *private_data,
  62                    uint32_t msg_type,
  63                    struct server_id server_id, DATA_BLOB *data);
  64         void *private_data;
  65 };
  66
  67 struct messaging_context {
  68         struct server_id id;
  69         struct tevent_context *event_ctx;
  70         struct messaging_callback *callbacks;
  71
  72         struct tevent_req **new_waiters;
  73         unsigned num_new_waiters;
  74
  75         struct tevent_req **waiters;
  76         unsigned num_waiters;
  77
  78         struct messaging_backend *remote;
  79
  80         struct server_id_db *names_db;
  81 };
  82
  83 struct messaging_hdr {
  84         uint32_t msg_type;
  85         struct server_id dst;
  86         struct server_id src;
  87 };
  88
  89 /****************************************************************************
  90  A useful function for testing the message system.
  91 ****************************************************************************/
  92
  93 static void ping_message(struct messaging_context *msg_ctx,
  94                          void *private_data,
  95                          uint32_t msg_type,
  96                          struct server_id src,
  97                          DATA_BLOB *data)
  98 {
  99         struct server_id_buf idbuf;
 100
 101         DEBUG(1, ("INFO: Received PING message from PID %s [%.*s]\n",
 102                   server_id_str_buf(src, &idbuf), (int)data->length,
 103                   data->data ? (char *)data->data : ""));
 104
 105         messaging_send(msg_ctx, src, MSG_PONG, data);
 106 }
 107
 108 /****************************************************************************
 109  Register/replace a dispatch function for a particular message type.
 110  JRA changed Dec 13 2006. Only one message handler now permitted per type.
 111  *NOTE*: Dispatch functions must be able to cope with incoming
 112  messages on an *odd* byte boundary.
 113 ****************************************************************************/
 114
 115 struct msg_all {
 116         struct messaging_context *msg_ctx;
 117         int msg_type;
 118         uint32 msg_flag;
 119         const void *buf;
 120         size_t len;
 121         int n_sent;
 122 };
 123
 124 /****************************************************************************
 125  Send one of the messages for the broadcast.
 126 ****************************************************************************/
 127
 128 static int traverse_fn(struct db_record *rec, const struct server_id *id,
 129                        uint32_t msg_flags, void *state)
 130 {
 131         struct msg_all *msg_all = (struct msg_all *)state;
 132         NTSTATUS status;
 133
 134         /* Don't send if the receiver hasn't registered an interest. */
 135
 136         if((msg_flags & msg_all->msg_flag) == 0) {
 137                 return 0;
 138         }
 139
 140         /* If the msg send fails because the pid was not found (i.e. smbd died),
 141          * the msg has already been deleted from the messages.tdb.*/
 142
 143         status = messaging_send_buf(msg_all->msg_ctx, *id, msg_all->msg_type,
 144                                     (const uint8_t *)msg_all->buf, msg_all->len);
 145
 146         if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
 147                 struct server_id_buf idbuf;
 148
 149                 /*
 150                  * If the pid was not found delete the entry from
 151                  * serverid.tdb
 152                  */
 153
 154                 DEBUG(2, ("pid %s doesn't exist\n",
 155                           server_id_str_buf(*id, &idbuf)));
 156
 157                 dbwrap_record_delete(rec);
 158         }
 159         msg_all->n_sent++;
 160         return 0;
 161 }
 162
 163 /**
 164  * Send a message to all smbd processes.
 165  *
 166  * It isn't very efficient, but should be OK for the sorts of
 167  * applications that use it. When we need efficient broadcast we can add
 168  * it.
 169  *
 170  * @param n_sent Set to the number of messages sent.  This should be
 171  * equal to the number of processes, but be careful for races.
 172  *
 173  * @retval True for success.
 174  **/
 175 bool message_send_all(struct messaging_context *msg_ctx,
 176                       int msg_type,
 177                       const void *buf, size_t len,
 178                       int *n_sent)
 179 {
 180         struct msg_all msg_all;
 181
 182         msg_all.msg_type = msg_type;
 183         if (msg_type < 0x100) {
 184                 msg_all.msg_flag = FLAG_MSG_GENERAL;
 185         } else if (msg_type > 0x100 && msg_type < 0x200) {
 186                 msg_all.msg_flag = FLAG_MSG_NMBD;
 187         } else if (msg_type > 0x200 && msg_type < 0x300) {
 188                 msg_all.msg_flag = FLAG_MSG_PRINT_GENERAL;
 189         } else if (msg_type > 0x300 && msg_type < 0x400) {
 190                 msg_all.msg_flag = FLAG_MSG_SMBD;
 191         } else if (msg_type > 0x400 && msg_type < 0x600) {
 192                 msg_all.msg_flag = FLAG_MSG_WINBIND;
 193         } else if (msg_type > 4000 && msg_type < 5000) {
 194                 msg_all.msg_flag = FLAG_MSG_DBWRAP;
 195         } else {
 196                 return false;
 197         }
 198
 199         msg_all.buf = buf;
 200         msg_all.len = len;
 201         msg_all.n_sent = 0;
 202         msg_all.msg_ctx = msg_ctx;
 203
 204         serverid_traverse(traverse_fn, &msg_all);
 205         if (n_sent)
 206                 *n_sent = msg_all.n_sent;
 207         return true;
 208 }
 209
 210 static void messaging_recv_cb(const uint8_t *msg, size_t msg_len,
 211                               int *fds, size_t num_fds,
 212                               void *private_data)
 213 {
 214         struct messaging_context *msg_ctx = talloc_get_type_abort(
 215                 private_data, struct messaging_context);
 216         const struct messaging_hdr *hdr;
 217         struct server_id_buf idbuf;
 218         struct messaging_rec rec;
 219         int64_t fds64[MIN(num_fds, INT8_MAX)];
 220         size_t i;
 221
 222         if (msg_len < sizeof(*hdr)) {
 223                 for (i=0; i < num_fds; i++) {
 224                         close(fds[i]);
 225                 }
 226                 DEBUG(1, ("message too short: %u\n", (unsigned)msg_len));
 227                 return;
 228         }
 229
 230         if (num_fds > INT8_MAX) {
 231                 for (i=0; i < num_fds; i++) {
 232                         close(fds[i]);
 233                 }
 234                 DEBUG(1, ("too many fds: %u\n", (unsigned)num_fds));
 235                 return;
 236         }
 237
 238         /*
 239          * "consume" the fds by copying them and setting
 240          * the original variable to -1
 241          */
 242         for (i=0; i < num_fds; i++) {
 243                 fds64[i] = fds[i];
 244                 fds[i] = -1;
 245         }
 246
 247         /*
 248          * messages_dgm guarantees alignment, so we can cast here
 249          */
 250         hdr = (const struct messaging_hdr *)msg;
 251
 252         DEBUG(10, ("%s: Received message 0x%x len %u (num_fds:%u) from %s\n",
 253                    __func__, (unsigned)hdr->msg_type,
 254                    (unsigned)(msg_len - sizeof(*hdr)),
 255                    (unsigned)num_fds,
 256                    server_id_str_buf(hdr->src, &idbuf)));
 257
 258         rec = (struct messaging_rec) {
 259                 .msg_version = MESSAGE_VERSION,
 260                 .msg_type = hdr->msg_type,
 261                 .src = hdr->src,
 262                 .dest = hdr->dst,
 263                 .buf.data = discard_const_p(uint8, msg) + sizeof(*hdr),
 264                 .buf.length = msg_len - sizeof(*hdr),
 265                 .num_fds = num_fds,
 266                 .fds = fds64,
 267         };
 268
 269         messaging_dispatch_rec(msg_ctx, &rec);
 270 }
 271
 272 static int messaging_context_destructor(struct messaging_context *ctx)
 273 {
 274         unsigned i;
 275
 276         messaging_dgm_destroy();
 277
 278         for (i=0; i<ctx->num_new_waiters; i++) {
 279                 if (ctx->new_waiters[i] != NULL) {
 280                         tevent_req_set_cleanup_fn(ctx->new_waiters[i], NULL);
 281                         ctx->new_waiters[i] = NULL;
 282                 }
 283         }
 284         for (i=0; i<ctx->num_waiters; i++) {
 285                 if (ctx->waiters[i] != NULL) {
 286                         tevent_req_set_cleanup_fn(ctx->waiters[i], NULL);
 287                         ctx->waiters[i] = NULL;
 288                 }
 289         }
 290
 291         return 0;
 292 }
 293
 294 struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx,
 295                                          struct tevent_context *ev)
 296 {
 297         struct messaging_context *ctx;
 298         NTSTATUS status;
 299         int ret;
 300
 301         if (!(ctx = talloc_zero(mem_ctx, struct messaging_context))) {
 302                 return NULL;
 303         }
 304
 305         ctx->id = procid_self();
 306         ctx->event_ctx = ev;
 307
 308         sec_init();
 309
 310         ret = messaging_dgm_init(ctx->event_ctx, ctx->id,
 311                                  lp_cache_directory(), sec_initial_uid(),
 312                                  messaging_recv_cb, ctx);
 313
 314         if (ret != 0) {
 315                 DEBUG(2, ("messaging_dgm_init failed: %s\n", strerror(ret)));
 316                 TALLOC_FREE(ctx);
 317                 return NULL;
 318         }
 319
 320         ctx->names_db = server_id_db_init(
 321                 ctx, ctx->id, lp_cache_directory(), 0,
 322                 TDB_INCOMPATIBLE_HASH|TDB_CLEAR_IF_FIRST);
 323         if (ctx->names_db == NULL) {
 324                 DEBUG(10, ("%s: server_id_db_init failed\n", __func__));
 325                 TALLOC_FREE(ctx);
 326                 return NULL;
 327         }
 328
 329         talloc_set_destructor(ctx, messaging_context_destructor);
 330
 331         if (lp_clustering()) {
 332                 status = messaging_ctdbd_init(ctx, ctx, &ctx->remote);
 333
 334                 if (!NT_STATUS_IS_OK(status)) {
 335                         DEBUG(2, ("messaging_ctdbd_init failed: %s\n",
 336                                   nt_errstr(status)));
 337                         TALLOC_FREE(ctx);
 338                         return NULL;
 339                 }
 340         }
 341         ctx->id.vnn = get_my_vnn();
 342
 343         messaging_register(ctx, NULL, MSG_PING, ping_message);
 344
 345         /* Register some debugging related messages */
 346
 347         register_msg_pool_usage(ctx);
 348         register_dmalloc_msgs(ctx);
 349         debug_register_msgs(ctx);
 350
 351         return ctx;
 352 }
 353
 354 struct server_id messaging_server_id(const struct messaging_context *msg_ctx)
 355 {
 356         return msg_ctx->id;
 357 }
 358
 359 /*
 360  * re-init after a fork
 361  */
 362 NTSTATUS messaging_reinit(struct messaging_context *msg_ctx)
 363 {
 364         NTSTATUS status;
 365         int ret;
 366
 367         messaging_dgm_destroy();
 368
 369         msg_ctx->id = procid_self();
 370
 371         ret = messaging_dgm_init(msg_ctx->event_ctx, msg_ctx->id,
 372                                  lp_cache_directory(), sec_initial_uid(),
 373                                  messaging_recv_cb, msg_ctx);
 374         if (ret != 0) {
 375                 DEBUG(0, ("messaging_dgm_init failed: %s\n", strerror(errno)));
 376                 return map_nt_error_from_unix(ret);
 377         }
 378
 379         TALLOC_FREE(msg_ctx->remote);
 380
 381         if (lp_clustering()) {
 382                 status = messaging_ctdbd_init(msg_ctx, msg_ctx,
 383                                               &msg_ctx->remote);
 384
 385                 if (!NT_STATUS_IS_OK(status)) {
 386                         DEBUG(1, ("messaging_ctdbd_init failed: %s\n",
 387                                   nt_errstr(status)));
 388                         return status;
 389                 }
 390         }
 391
 392         server_id_db_reinit(msg_ctx->names_db, msg_ctx->id);
 393
 394         return NT_STATUS_OK;
 395 }
 396
 397
 398 /*
 399  * Register a dispatch function for a particular message type. Allow multiple
 400  * registrants
 401 */
 402 NTSTATUS messaging_register(struct messaging_context *msg_ctx,
 403                             void *private_data,
 404                             uint32_t msg_type,
 405                             void (*fn)(struct messaging_context *msg,
 406                                        void *private_data,
 407                                        uint32_t msg_type,
 408                                        struct server_id server_id,
 409                                        DATA_BLOB *data))
 410 {
 411         struct messaging_callback *cb;
 412
 413         DEBUG(5, ("Registering messaging pointer for type %u - "
 414                   "private_data=%p\n",
 415                   (unsigned)msg_type, private_data));
 416
 417         /*
 418          * Only one callback per type
 419          */
 420
 421         for (cb = msg_ctx->callbacks; cb != NULL; cb = cb->next) {
 422                 /* we allow a second registration of the same message
 423                    type if it has a different private pointer. This is
 424                    needed in, for example, the internal notify code,
 425                    which creates a new notify context for each tree
 426                    connect, and expects to receive messages to each of
 427                    them. */
 428                 if (cb->msg_type == msg_type && private_data == cb->private_data) {
 429                         DEBUG(5,("Overriding messaging pointer for type %u - private_data=%p\n",
 430                                   (unsigned)msg_type, private_data));
 431                         cb->fn = fn;
 432                         cb->private_data = private_data;
 433                         return NT_STATUS_OK;
 434                 }
 435         }
 436
 437         if (!(cb = talloc(msg_ctx, struct messaging_callback))) {
 438                 return NT_STATUS_NO_MEMORY;
 439         }
 440
 441         cb->msg_type = msg_type;
 442         cb->fn = fn;
 443         cb->private_data = private_data;
 444
 445         DLIST_ADD(msg_ctx->callbacks, cb);
 446         return NT_STATUS_OK;
 447 }
 448
 449 /*
 450   De-register the function for a particular message type.
 451 */
 452 void messaging_deregister(struct messaging_context *ctx, uint32_t msg_type,
 453                           void *private_data)
 454 {
 455         struct messaging_callback *cb, *next;
 456
 457         for (cb = ctx->callbacks; cb; cb = next) {
 458                 next = cb->next;
 459                 if ((cb->msg_type == msg_type)
 460                     && (cb->private_data == private_data)) {
 461                         DEBUG(5,("Deregistering messaging pointer for type %u - private_data=%p\n",
 462                                   (unsigned)msg_type, private_data));
 463                         DLIST_REMOVE(ctx->callbacks, cb);
 464                         TALLOC_FREE(cb);
 465                 }
 466         }
 467 }
 468
 469 /*
 470   Send a message to a particular server
 471 */
 472 NTSTATUS messaging_send(struct messaging_context *msg_ctx,
 473                         struct server_id server, uint32_t msg_type,
 474                         const DATA_BLOB *data)
 475 {
 476         struct iovec iov;
 477
 478         iov.iov_base = data->data;
 479         iov.iov_len = data->length;
 480
 481         return messaging_send_iov(msg_ctx, server, msg_type, &iov, 1, NULL, 0);
 482 }
 483
 484 NTSTATUS messaging_send_buf(struct messaging_context *msg_ctx,
 485                             struct server_id server, uint32_t msg_type,
 486                             const uint8_t *buf, size_t len)
 487 {
 488         DATA_BLOB blob = data_blob_const(buf, len);
 489         return messaging_send(msg_ctx, server, msg_type, &blob);
 490 }
 491
 492 NTSTATUS messaging_send_iov(struct messaging_context *msg_ctx,
 493                             struct server_id server, uint32_t msg_type,
 494                             const struct iovec *iov, int iovlen,
 495                             const int *fds, size_t num_fds)
 496 {
 497         int ret;
 498         struct messaging_hdr hdr;
 499         struct iovec iov2[iovlen+1];
 500
 501         if (server_id_is_disconnected(&server)) {
 502                 return NT_STATUS_INVALID_PARAMETER_MIX;
 503         }
 504
 505         if (num_fds > INT8_MAX) {
 506                 return NT_STATUS_INVALID_PARAMETER_MIX;
 507         }
 508
 509         if (!procid_is_local(&server)) {
 510                 if (num_fds > 0) {
 511                         return NT_STATUS_NOT_SUPPORTED;
 512                 }
 513
 514                 ret = msg_ctx->remote->send_fn(msg_ctx->id, server,
 515                                                msg_type, iov, iovlen,
 516                                                NULL, 0,
 517                                                msg_ctx->remote);
 518                 if (ret != 0) {
 519                         return map_nt_error_from_unix(ret);
 520                 }
 521                 return NT_STATUS_OK;
 522         }
 523
 524         ZERO_STRUCT(hdr);
 525         hdr = (struct messaging_hdr) {
 526                 .msg_type = msg_type,
 527                 .dst = server,
 528                 .src = msg_ctx->id
 529         };
 530         iov2[0] = (struct iovec){ .iov_base = &hdr, .iov_len = sizeof(hdr) };
 531         memcpy(&iov2[1], iov, iovlen * sizeof(*iov));
 532
 533         become_root();
 534         ret = messaging_dgm_send(server.pid, iov2, iovlen+1, fds, num_fds);
 535         unbecome_root();
 536
 537         if (ret != 0) {
 538                 return map_nt_error_from_unix(ret);
 539         }
 540         return NT_STATUS_OK;
 541 }
 542
 543 static struct messaging_rec *messaging_rec_dup(TALLOC_CTX *mem_ctx,
 544                                                struct messaging_rec *rec)
 545 {
 546         struct messaging_rec *result;
 547         size_t fds_size = sizeof(int64_t) * rec->num_fds;
 548
 549         result = talloc_pooled_object(mem_ctx, struct messaging_rec, 2,
 550                                       rec->buf.length + fds_size);
 551         if (result == NULL) {
 552                 return NULL;
 553         }
 554         *result = *rec;
 555
 556         /* Doesn't fail, see talloc_pooled_object */
 557
 558         result->buf.data = talloc_memdup(result, rec->buf.data,
 559                                          rec->buf.length);
 560
 561         result->fds = NULL;
 562         if (result->num_fds > 0) {
 563                 result->fds = talloc_array(result, int64_t, result->num_fds);
 564                 memcpy(result->fds, rec->fds, fds_size);
 565         }
 566
 567         return result;
 568 }
 569
 570 struct messaging_filtered_read_state {
 571         struct tevent_context *ev;
 572         struct messaging_context *msg_ctx;
 573         void *tevent_handle;
 574
 575         bool (*filter)(struct messaging_rec *rec, void *private_data);
 576         void *private_data;
 577
 578         struct messaging_rec *rec;
 579 };
 580
 581 static void messaging_filtered_read_cleanup(struct tevent_req *req,
 582                                             enum tevent_req_state req_state);
 583
 584 struct tevent_req *messaging_filtered_read_send(
 585         TALLOC_CTX *mem_ctx, struct tevent_context *ev,
 586         struct messaging_context *msg_ctx,
 587         bool (*filter)(struct messaging_rec *rec, void *private_data),
 588         void *private_data)
 589 {
 590         struct tevent_req *req;
 591         struct messaging_filtered_read_state *state;
 592         size_t new_waiters_len;
 593
 594         req = tevent_req_create(mem_ctx, &state,
 595                                 struct messaging_filtered_read_state);
 596         if (req == NULL) {
 597                 return NULL;
 598         }
 599         state->ev = ev;
 600         state->msg_ctx = msg_ctx;
 601         state->filter = filter;
 602         state->private_data = private_data;
 603
 604         /*
 605          * We have to defer the callback here, as we might be called from
 606          * within a different tevent_context than state->ev
 607          */
 608         tevent_req_defer_callback(req, state->ev);
 609
 610         state->tevent_handle = messaging_dgm_register_tevent_context(
 611                 state, ev);
 612         if (tevent_req_nomem(state, req)) {
 613                 return tevent_req_post(req, ev);
 614         }
 615
 616         /*
 617          * We add ourselves to the "new_waiters" array, not the "waiters"
 618          * array. If we are called from within messaging_read_done,
 619          * messaging_dispatch_rec will be in an active for-loop on
 620          * "waiters". We must be careful not to mess with this array, because
 621          * it could mean that a single event is being delivered twice.
 622          */
 623
 624         new_waiters_len = talloc_array_length(msg_ctx->new_waiters);
 625
 626         if (new_waiters_len == msg_ctx->num_new_waiters) {
 627                 struct tevent_req **tmp;
 628
 629                 tmp = talloc_realloc(msg_ctx, msg_ctx->new_waiters,
 630                                      struct tevent_req *, new_waiters_len+1);
 631                 if (tevent_req_nomem(tmp, req)) {
 632                         return tevent_req_post(req, ev);
 633                 }
 634                 msg_ctx->new_waiters = tmp;
 635         }
 636
 637         msg_ctx->new_waiters[msg_ctx->num_new_waiters] = req;
 638         msg_ctx->num_new_waiters += 1;
 639         tevent_req_set_cleanup_fn(req, messaging_filtered_read_cleanup);
 640
 641         return req;
 642 }
 643
 644 static void messaging_filtered_read_cleanup(struct tevent_req *req,
 645                                             enum tevent_req_state req_state)
 646 {
 647         struct messaging_filtered_read_state *state = tevent_req_data(
 648                 req, struct messaging_filtered_read_state);
 649         struct messaging_context *msg_ctx = state->msg_ctx;
 650         unsigned i;
 651
 652         tevent_req_set_cleanup_fn(req, NULL);
 653
 654         TALLOC_FREE(state->tevent_handle);
 655
 656         /*
 657          * Just set the [new_]waiters entry to NULL, be careful not to mess
 658          * with the other "waiters" array contents. We are often called from
 659          * within "messaging_dispatch_rec", which loops over
 660          * "waiters". Messing with the "waiters" array will mess up that
 661          * for-loop.
 662          */
 663
 664         for (i=0; i<msg_ctx->num_waiters; i++) {
 665                 if (msg_ctx->waiters[i] == req) {
 666                         msg_ctx->waiters[i] = NULL;
 667                         return;
 668                 }
 669         }
 670
 671         for (i=0; i<msg_ctx->num_new_waiters; i++) {
 672                 if (msg_ctx->new_waiters[i] == req) {
 673                         msg_ctx->new_waiters[i] = NULL;
 674                         return;
 675                 }
 676         }
 677 }
 678
 679 static void messaging_filtered_read_done(struct tevent_req *req,
 680                                          struct messaging_rec *rec)
 681 {
 682         struct messaging_filtered_read_state *state = tevent_req_data(
 683                 req, struct messaging_filtered_read_state);
 684
 685         state->rec = messaging_rec_dup(state, rec);
 686         if (tevent_req_nomem(state->rec, req)) {
 687                 return;
 688         }
 689         tevent_req_done(req);
 690 }
 691
 692 int messaging_filtered_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 693                                  struct messaging_rec **presult)
 694 {
 695         struct messaging_filtered_read_state *state = tevent_req_data(
 696                 req, struct messaging_filtered_read_state);
 697         int err;
 698
 699         if (tevent_req_is_unix_error(req, &err)) {
 700                 tevent_req_received(req);
 701                 return err;
 702         }
 703         *presult = talloc_move(mem_ctx, &state->rec);
 704         return 0;
 705 }
 706
 707 struct messaging_read_state {
 708         uint32_t msg_type;
 709         struct messaging_rec *rec;
 710 };
 711
 712 static bool messaging_read_filter(struct messaging_rec *rec,
 713                                   void *private_data);
 714 static void messaging_read_done(struct tevent_req *subreq);
 715
 716 struct tevent_req *messaging_read_send(TALLOC_CTX *mem_ctx,
 717                                        struct tevent_context *ev,
 718                                        struct messaging_context *msg,
 719                                        uint32_t msg_type)
 720 {
 721         struct tevent_req *req, *subreq;
 722         struct messaging_read_state *state;
 723
 724         req = tevent_req_create(mem_ctx, &state,
 725                                 struct messaging_read_state);
 726         if (req == NULL) {
 727                 return NULL;
 728         }
 729         state->msg_type = msg_type;
 730
 731         subreq = messaging_filtered_read_send(state, ev, msg,
 732                                               messaging_read_filter, state);
 733         if (tevent_req_nomem(subreq, req)) {
 734                 return tevent_req_post(req, ev);
 735         }
 736         tevent_req_set_callback(subreq, messaging_read_done, req);
 737         return req;
 738 }
 739
 740 static bool messaging_read_filter(struct messaging_rec *rec,
 741                                   void *private_data)
 742 {
 743         struct messaging_read_state *state = talloc_get_type_abort(
 744                 private_data, struct messaging_read_state);
 745
 746         if (rec->num_fds != 0) {
 747                 return false;
 748         }
 749
 750         return rec->msg_type == state->msg_type;
 751 }
 752
 753 static void messaging_read_done(struct tevent_req *subreq)
 754 {
 755         struct tevent_req *req = tevent_req_callback_data(
 756                 subreq, struct tevent_req);
 757         struct messaging_read_state *state = tevent_req_data(
 758                 req, struct messaging_read_state);
 759         int ret;
 760
 761         ret = messaging_filtered_read_recv(subreq, state, &state->rec);
 762         TALLOC_FREE(subreq);
 763         if (tevent_req_error(req, ret)) {
 764                 return;
 765         }
 766         tevent_req_done(req);
 767 }
 768
 769 int messaging_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 770                         struct messaging_rec **presult)
 771 {
 772         struct messaging_read_state *state = tevent_req_data(
 773                 req, struct messaging_read_state);
 774         int err;
 775
 776         if (tevent_req_is_unix_error(req, &err)) {
 777                 return err;
 778         }
 779         if (presult != NULL) {
 780                 *presult = talloc_move(mem_ctx, &state->rec);
 781         }
 782         return 0;
 783 }
 784
 785 static bool messaging_append_new_waiters(struct messaging_context *msg_ctx)
 786 {
 787         if (msg_ctx->num_new_waiters == 0) {
 788                 return true;
 789         }
 790
 791         if (talloc_array_length(msg_ctx->waiters) <
 792             (msg_ctx->num_waiters + msg_ctx->num_new_waiters)) {
 793                 struct tevent_req **tmp;
 794                 tmp = talloc_realloc(
 795                         msg_ctx, msg_ctx->waiters, struct tevent_req *,
 796                         msg_ctx->num_waiters + msg_ctx->num_new_waiters);
 797                 if (tmp == NULL) {
 798                         DEBUG(1, ("%s: talloc failed\n", __func__));
 799                         return false;
 800                 }
 801                 msg_ctx->waiters = tmp;
 802         }
 803
 804         memcpy(&msg_ctx->waiters[msg_ctx->num_waiters], msg_ctx->new_waiters,
 805                sizeof(struct tevent_req *) * msg_ctx->num_new_waiters);
 806
 807         msg_ctx->num_waiters += msg_ctx->num_new_waiters;
 808         msg_ctx->num_new_waiters = 0;
 809
 810         return true;
 811 }
 812
 813 /*
 814   Dispatch one messaging_rec
 815 */
 816 void messaging_dispatch_rec(struct messaging_context *msg_ctx,
 817                             struct messaging_rec *rec)
 818 {
 819         struct messaging_callback *cb, *next;
 820         unsigned i;
 821         size_t j;
 822
 823         for (cb = msg_ctx->callbacks; cb != NULL; cb = next) {
 824                 next = cb->next;
 825                 if (cb->msg_type != rec->msg_type) {
 826                         continue;
 827                 }
 828
 829                 /*
 830                  * the old style callbacks don't support fd passing
 831                  */
 832                 for (j=0; j < rec->num_fds; j++) {
 833                         int fd = rec->fds[j];
 834                         close(fd);
 835                 }
 836                 rec->num_fds = 0;
 837                 rec->fds = NULL;
 838
 839                 cb->fn(msg_ctx, cb->private_data, rec->msg_type,
 840                        rec->src, &rec->buf);
 841
 842                 /*
 843                  * we continue looking for matching messages after finding
 844                  * one. This matters for subsystems like the internal notify
 845                  * code which register more than one handler for the same
 846                  * message type
 847                  */
 848         }
 849
 850         if (!messaging_append_new_waiters(msg_ctx)) {
 851                 for (j=0; j < rec->num_fds; j++) {
 852                         int fd = rec->fds[j];
 853                         close(fd);
 854                 }
 855                 rec->num_fds = 0;
 856                 rec->fds = NULL;
 857                 return;
 858         }
 859
 860         i = 0;
 861         while (i < msg_ctx->num_waiters) {
 862                 struct tevent_req *req;
 863                 struct messaging_filtered_read_state *state;
 864
 865                 req = msg_ctx->waiters[i];
 866                 if (req == NULL) {
 867                         /*
 868                          * This got cleaned up. In the meantime,
 869                          * move everything down one. We need
 870                          * to keep the order of waiters, as
 871                          * other code may depend on this.
 872                          */
 873                         if (i < msg_ctx->num_waiters - 1) {
 874                                 memmove(&msg_ctx->waiters[i],
 875                                         &msg_ctx->waiters[i+1],
 876                                         sizeof(struct tevent_req *) *
 877                                             (msg_ctx->num_waiters - i - 1));
 878                         }
 879                         msg_ctx->num_waiters -= 1;
 880                         continue;
 881                 }
 882
 883                 state = tevent_req_data(
 884                         req, struct messaging_filtered_read_state);
 885                 if (state->filter(rec, state->private_data)) {
 886                         messaging_filtered_read_done(req, rec);
 887
 888                         /*
 889                          * Only the first one gets the fd-array
 890                          */
 891                         rec->num_fds = 0;
 892                         rec->fds = NULL;
 893                 }
 894
 895                 i += 1;
 896         }
 897
 898         /*
 899          * If the fd-array isn't used, just close it.
 900          */
 901         for (j=0; j < rec->num_fds; j++) {
 902                 int fd = rec->fds[j];
 903                 close(fd);
 904         }
 905         rec->num_fds = 0;
 906         rec->fds = NULL;
 907 }
 908
 909 static int mess_parent_dgm_cleanup(void *private_data);
 910 static void mess_parent_dgm_cleanup_done(struct tevent_req *req);
 911
 912 bool messaging_parent_dgm_cleanup_init(struct messaging_context *msg)
 913 {
 914         struct tevent_req *req;
 915
 916         req = background_job_send(
 917                 msg, msg->event_ctx, msg, NULL, 0,
 918                 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
 919                             60*15),
 920                 mess_parent_dgm_cleanup, msg);
 921         if (req == NULL) {
 922                 return false;
 923         }
 924         tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
 925         return true;
 926 }
 927
 928 static int mess_parent_dgm_cleanup(void *private_data)
 929 {
 930         int ret;
 931
 932         ret = messaging_dgm_wipe();
 933         DEBUG(10, ("messaging_dgm_wipe returned %s\n",
 934                    ret ? strerror(ret) : "ok"));
 935         return lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
 936                            60*15);
 937 }
 938
 939 static void mess_parent_dgm_cleanup_done(struct tevent_req *req)
 940 {
 941         struct messaging_context *msg = tevent_req_callback_data(
 942                 req, struct messaging_context);
 943         NTSTATUS status;
 944
 945         status = background_job_recv(req);
 946         TALLOC_FREE(req);
 947         DEBUG(1, ("messaging dgm cleanup job ended with %s\n",
 948                   nt_errstr(status)));
 949
 950         req = background_job_send(
 951                 msg, msg->event_ctx, msg, NULL, 0,
 952                 lp_parm_int(-1, "messaging", "messaging dgm cleanup interval",
 953                             60*15),
 954                 mess_parent_dgm_cleanup, msg);
 955         if (req == NULL) {
 956                 DEBUG(1, ("background_job_send failed\n"));
 957         }
 958         tevent_req_set_callback(req, mess_parent_dgm_cleanup_done, msg);
 959 }
 960
 961 int messaging_cleanup(struct messaging_context *msg_ctx, pid_t pid)
 962 {
 963         int ret;
 964
 965         if (pid == 0) {
 966                 ret = messaging_dgm_wipe();
 967         } else {
 968                 ret = messaging_dgm_cleanup(pid);
 969         }
 970
 971         return ret;
 972 }
 973
 974 struct tevent_context *messaging_tevent_context(
 975         struct messaging_context *msg_ctx)
 976 {
 977         return msg_ctx->event_ctx;
 978 }
 979
 980 struct server_id_db *messaging_names_db(struct messaging_context *msg_ctx)
 981 {
 982         return msg_ctx->names_db;
 983 }
 984
 985 /** @} **/