dbus/dbus-transport-socket.c

   1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
   2 /* dbus-transport-socket.c  Socket subclasses of DBusTransport
   3  *
   4  * Copyright (C) 2002, 2003, 2004, 2006  Red Hat Inc.
   5  *
   6  * Licensed under the Academic Free License version 2.1
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  21  *
  22  */
  23
  24 #include "dbus-internals.h"
  25 #include "dbus-connection-internal.h"
  26 #include "dbus-transport-socket.h"
  27 #include "dbus-transport-protected.h"
  28 #include "dbus-watch.h"
  29 #include "dbus-credentials.h"
  30
  31
  32 /**
  33  * @defgroup DBusTransportSocket DBusTransport implementations for sockets
  34  * @ingroup  DBusInternals
  35  * @brief Implementation details of DBusTransport on sockets
  36  *
  37  * @{
  38  */
  39
  40 /**
  41  * Opaque object representing a socket file descriptor transport.
  42  */
  43 typedef struct DBusTransportSocket DBusTransportSocket;
  44
  45 /**
  46  * Implementation details of DBusTransportSocket. All members are private.
  47  */
  48 struct DBusTransportSocket
  49 {
  50   DBusTransport base;                   /**< Parent instance */
  51   int fd;                               /**< File descriptor. */
  52   DBusWatch *read_watch;                /**< Watch for readability. */
  53   DBusWatch *write_watch;               /**< Watch for writability. */
  54
  55   int max_bytes_read_per_iteration;     /**< To avoid blocking too long. */
  56   int max_bytes_written_per_iteration;  /**< To avoid blocking too long. */
  57
  58   int message_bytes_written;            /**< Number of bytes of current
  59                                          *   outgoing message that have
  60                                          *   been written.
  61                                          */
  62   DBusString encoded_outgoing;          /**< Encoded version of current
  63                                          *   outgoing message.
  64                                          */
  65   DBusString encoded_incoming;          /**< Encoded version of current
  66                                          *   incoming data.
  67                                          */
  68 };
  69
  70 static void
  71 free_watches (DBusTransport *transport)
  72 {
  73   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
  74
  75   _dbus_verbose ("%s start\n", _DBUS_FUNCTION_NAME);
  76
  77   if (socket_transport->read_watch)
  78     {
  79       if (transport->connection)
  80         _dbus_connection_remove_watch_unlocked (transport->connection,
  81                                                 socket_transport->read_watch);
  82       _dbus_watch_invalidate (socket_transport->read_watch);
  83       _dbus_watch_unref (socket_transport->read_watch);
  84       socket_transport->read_watch = NULL;
  85     }
  86
  87   if (socket_transport->write_watch)
  88     {
  89       if (transport->connection)
  90         _dbus_connection_remove_watch_unlocked (transport->connection,
  91                                                 socket_transport->write_watch);
  92       _dbus_watch_invalidate (socket_transport->write_watch);
  93       _dbus_watch_unref (socket_transport->write_watch);
  94       socket_transport->write_watch = NULL;
  95     }
  96
  97   _dbus_verbose ("%s end\n", _DBUS_FUNCTION_NAME);
  98 }
  99
 100 static void
 101 socket_finalize (DBusTransport *transport)
 102 {
 103   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 104
 105   _dbus_verbose ("%s\n", _DBUS_FUNCTION_NAME);
 106
 107   free_watches (transport);
 108
 109   _dbus_string_free (&socket_transport->encoded_outgoing);
 110   _dbus_string_free (&socket_transport->encoded_incoming);
 111
 112   _dbus_transport_finalize_base (transport);
 113
 114   _dbus_assert (socket_transport->read_watch == NULL);
 115   _dbus_assert (socket_transport->write_watch == NULL);
 116
 117   dbus_free (transport);
 118 }
 119
 120 static void
 121 check_write_watch (DBusTransport *transport)
 122 {
 123   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 124   dbus_bool_t needed;
 125
 126   if (transport->connection == NULL)
 127     return;
 128
 129   if (transport->disconnected)
 130     {
 131       _dbus_assert (socket_transport->write_watch == NULL);
 132       return;
 133     }
 134
 135   _dbus_transport_ref (transport);
 136
 137   if (_dbus_transport_get_is_authenticated (transport))
 138     needed = _dbus_connection_has_messages_to_send_unlocked (transport->connection);
 139   else
 140     {
 141       if (transport->send_credentials_pending)
 142         needed = TRUE;
 143       else
 144         {
 145           DBusAuthState auth_state;
 146
 147           auth_state = _dbus_auth_do_work (transport->auth);
 148
 149           /* If we need memory we install the write watch just in case,
 150            * if there's no need for it, it will get de-installed
 151            * next time we try reading.
 152            */
 153           if (auth_state == DBUS_AUTH_STATE_HAVE_BYTES_TO_SEND ||
 154               auth_state == DBUS_AUTH_STATE_WAITING_FOR_MEMORY)
 155             needed = TRUE;
 156           else
 157             needed = FALSE;
 158         }
 159     }
 160
 161   _dbus_verbose ("check_write_watch(): needed = %d on connection %p watch %p fd = %d outgoing messages exist %d\n",
 162                  needed, transport->connection, socket_transport->write_watch,
 163                  socket_transport->fd,
 164                  _dbus_connection_has_messages_to_send_unlocked (transport->connection));
 165
 166   _dbus_connection_toggle_watch_unlocked (transport->connection,
 167                                           socket_transport->write_watch,
 168                                           needed);
 169
 170   _dbus_transport_unref (transport);
 171 }
 172
 173 static void
 174 check_read_watch (DBusTransport *transport)
 175 {
 176   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 177   dbus_bool_t need_read_watch;
 178
 179   _dbus_verbose ("%s: fd = %d\n",
 180                  _DBUS_FUNCTION_NAME, socket_transport->fd);
 181
 182   if (transport->connection == NULL)
 183     return;
 184
 185   if (transport->disconnected)
 186     {
 187       _dbus_assert (socket_transport->read_watch == NULL);
 188       return;
 189     }
 190
 191   _dbus_transport_ref (transport);
 192
 193   if (_dbus_transport_get_is_authenticated (transport))
 194     need_read_watch =
 195       _dbus_counter_get_value (transport->live_messages_size) < transport->max_live_messages_size;
 196   else
 197     {
 198       if (transport->receive_credentials_pending)
 199         need_read_watch = TRUE;
 200       else
 201         {
 202           /* The reason to disable need_read_watch when not WAITING_FOR_INPUT
 203            * is to avoid spinning on the file descriptor when we're waiting
 204            * to write or for some other part of the auth process
 205            */
 206           DBusAuthState auth_state;
 207
 208           auth_state = _dbus_auth_do_work (transport->auth);
 209
 210           /* If we need memory we install the read watch just in case,
 211            * if there's no need for it, it will get de-installed
 212            * next time we try reading. If we're authenticated we
 213            * install it since we normally have it installed while
 214            * authenticated.
 215            */
 216           if (auth_state == DBUS_AUTH_STATE_WAITING_FOR_INPUT ||
 217               auth_state == DBUS_AUTH_STATE_WAITING_FOR_MEMORY ||
 218               auth_state == DBUS_AUTH_STATE_AUTHENTICATED)
 219             need_read_watch = TRUE;
 220           else
 221             need_read_watch = FALSE;
 222         }
 223     }
 224
 225   _dbus_verbose ("  setting read watch enabled = %d\n", need_read_watch);
 226   _dbus_connection_toggle_watch_unlocked (transport->connection,
 227                                           socket_transport->read_watch,
 228                                           need_read_watch);
 229
 230   _dbus_transport_unref (transport);
 231 }
 232
 233 static void
 234 do_io_error (DBusTransport *transport)
 235 {
 236   _dbus_transport_ref (transport);
 237   _dbus_transport_disconnect (transport);
 238   _dbus_transport_unref (transport);
 239 }
 240
 241 /* return value is whether we successfully read any new data. */
 242 static dbus_bool_t
 243 read_data_into_auth (DBusTransport *transport,
 244                      dbus_bool_t   *oom)
 245 {
 246   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 247   DBusString *buffer;
 248   int bytes_read;
 249
 250   *oom = FALSE;
 251
 252   _dbus_auth_get_buffer (transport->auth, &buffer);
 253
 254   bytes_read = _dbus_read_socket (socket_transport->fd,
 255                                   buffer, socket_transport->max_bytes_read_per_iteration);
 256
 257   _dbus_auth_return_buffer (transport->auth, buffer,
 258                             bytes_read > 0 ? bytes_read : 0);
 259
 260   if (bytes_read > 0)
 261     {
 262       _dbus_verbose (" read %d bytes in auth phase\n", bytes_read);
 263
 264       return TRUE;
 265     }
 266   else if (bytes_read < 0)
 267     {
 268       /* EINTR already handled for us */
 269
 270       if (_dbus_get_is_errno_enomem ())
 271         {
 272           *oom = TRUE;
 273         }
 274       else if (_dbus_get_is_errno_eagain_or_ewouldblock ())
 275         ; /* do nothing, just return FALSE below */
 276       else
 277         {
 278           _dbus_verbose ("Error reading from remote app: %s\n",
 279                          _dbus_strerror_from_errno ());
 280           do_io_error (transport);
 281         }
 282
 283       return FALSE;
 284     }
 285   else
 286     {
 287       _dbus_assert (bytes_read == 0);
 288
 289       _dbus_verbose ("Disconnected from remote app\n");
 290       do_io_error (transport);
 291
 292       return FALSE;
 293     }
 294 }
 295
 296 /* Return value is whether we successfully wrote any bytes */
 297 static dbus_bool_t
 298 write_data_from_auth (DBusTransport *transport)
 299 {
 300   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 301   int bytes_written;
 302   const DBusString *buffer;
 303
 304   if (!_dbus_auth_get_bytes_to_send (transport->auth,
 305                                      &buffer))
 306     return FALSE;
 307
 308   bytes_written = _dbus_write_socket (socket_transport->fd,
 309                                       buffer,
 310                                       0, _dbus_string_get_length (buffer));
 311
 312   if (bytes_written > 0)
 313     {
 314       _dbus_auth_bytes_sent (transport->auth, bytes_written);
 315       return TRUE;
 316     }
 317   else if (bytes_written < 0)
 318     {
 319       /* EINTR already handled for us */
 320
 321       if (_dbus_get_is_errno_eagain_or_ewouldblock ())
 322         ;
 323       else
 324         {
 325           _dbus_verbose ("Error writing to remote app: %s\n",
 326                          _dbus_strerror_from_errno ());
 327           do_io_error (transport);
 328         }
 329     }
 330
 331   return FALSE;
 332 }
 333
 334 /* FALSE on OOM */
 335 static dbus_bool_t
 336 exchange_credentials (DBusTransport *transport,
 337                       dbus_bool_t    do_reading,
 338                       dbus_bool_t    do_writing)
 339 {
 340   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 341   DBusError error = DBUS_ERROR_INIT;
 342
 343   _dbus_verbose ("exchange_credentials: do_reading = %d, do_writing = %d\n",
 344                   do_reading, do_writing);
 345
 346   if (do_writing && transport->send_credentials_pending)
 347     {
 348       if (_dbus_send_credentials_socket (socket_transport->fd,
 349                                          &error))
 350         {
 351           transport->send_credentials_pending = FALSE;
 352         }
 353       else
 354         {
 355           _dbus_verbose ("Failed to write credentials: %s\n", error.message);
 356           dbus_error_free (&error);
 357           do_io_error (transport);
 358         }
 359     }
 360
 361   if (do_reading && transport->receive_credentials_pending)
 362     {
 363       /* FIXME this can fail due to IO error _or_ OOM, broken
 364        * (somewhat tricky to fix since the OOM error can be set after
 365        * we already read the credentials byte, so basically we need to
 366        * separate reading the byte and storing it in the
 367        * transport->credentials). Does not really matter for now
 368        * because storing in credentials never actually fails on unix.
 369        */
 370       if (_dbus_read_credentials_socket (socket_transport->fd,
 371                                          transport->credentials,
 372                                          &error))
 373         {
 374           transport->receive_credentials_pending = FALSE;
 375         }
 376       else
 377         {
 378           _dbus_verbose ("Failed to read credentials %s\n", error.message);
 379           dbus_error_free (&error);
 380           do_io_error (transport);
 381         }
 382     }
 383
 384   if (!(transport->send_credentials_pending ||
 385         transport->receive_credentials_pending))
 386     {
 387       if (!_dbus_auth_set_credentials (transport->auth,
 388                                        transport->credentials))
 389         return FALSE;
 390     }
 391
 392   return TRUE;
 393 }
 394
 395 static dbus_bool_t
 396 do_authentication (DBusTransport *transport,
 397                    dbus_bool_t    do_reading,
 398                    dbus_bool_t    do_writing,
 399                    dbus_bool_t   *auth_completed)
 400 {
 401   dbus_bool_t oom;
 402   dbus_bool_t orig_auth_state;
 403
 404   oom = FALSE;
 405
 406   orig_auth_state = _dbus_transport_get_is_authenticated (transport);
 407
 408   /* This is essential to avoid the check_write_watch() at the end,
 409    * we don't want to add a write watch in do_iteration before
 410    * we try writing and get EAGAIN
 411    */
 412   if (orig_auth_state)
 413     {
 414       if (auth_completed)
 415         *auth_completed = FALSE;
 416       return TRUE;
 417     }
 418
 419   _dbus_transport_ref (transport);
 420
 421   while (!_dbus_transport_get_is_authenticated (transport) &&
 422          _dbus_transport_get_is_connected (transport))
 423     {
 424       if (!exchange_credentials (transport, do_reading, do_writing))
 425         {
 426           /* OOM */
 427           oom = TRUE;
 428           goto out;
 429         }
 430
 431       if (transport->send_credentials_pending ||
 432           transport->receive_credentials_pending)
 433         {
 434           _dbus_verbose ("send_credentials_pending = %d receive_credentials_pending = %d\n",
 435                          transport->send_credentials_pending,
 436                          transport->receive_credentials_pending);
 437           goto out;
 438         }
 439
 440 #define TRANSPORT_SIDE(t) ((t)->is_server ? "server" : "client")
 441       switch (_dbus_auth_do_work (transport->auth))
 442         {
 443         case DBUS_AUTH_STATE_WAITING_FOR_INPUT:
 444           _dbus_verbose (" %s auth state: waiting for input\n",
 445                          TRANSPORT_SIDE (transport));
 446           if (!do_reading || !read_data_into_auth (transport, &oom))
 447             goto out;
 448           break;
 449
 450         case DBUS_AUTH_STATE_WAITING_FOR_MEMORY:
 451           _dbus_verbose (" %s auth state: waiting for memory\n",
 452                          TRANSPORT_SIDE (transport));
 453           oom = TRUE;
 454           goto out;
 455           break;
 456
 457         case DBUS_AUTH_STATE_HAVE_BYTES_TO_SEND:
 458           _dbus_verbose (" %s auth state: bytes to send\n",
 459                          TRANSPORT_SIDE (transport));
 460           if (!do_writing || !write_data_from_auth (transport))
 461             goto out;
 462           break;
 463
 464         case DBUS_AUTH_STATE_NEED_DISCONNECT:
 465           _dbus_verbose (" %s auth state: need to disconnect\n",
 466                          TRANSPORT_SIDE (transport));
 467           do_io_error (transport);
 468           break;
 469
 470         case DBUS_AUTH_STATE_AUTHENTICATED:
 471           _dbus_verbose (" %s auth state: authenticated\n",
 472                          TRANSPORT_SIDE (transport));
 473           break;
 474         }
 475     }
 476
 477  out:
 478   if (auth_completed)
 479     *auth_completed = (orig_auth_state != _dbus_transport_get_is_authenticated (transport));
 480
 481   check_read_watch (transport);
 482   check_write_watch (transport);
 483   _dbus_transport_unref (transport);
 484
 485   if (oom)
 486     return FALSE;
 487   else
 488     return TRUE;
 489 }
 490
 491 /* returns false on oom */
 492 static dbus_bool_t
 493 do_writing (DBusTransport *transport)
 494 {
 495   int total;
 496   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 497   dbus_bool_t oom;
 498
 499   /* No messages without authentication! */
 500   if (!_dbus_transport_get_is_authenticated (transport))
 501     {
 502       _dbus_verbose ("Not authenticated, not writing anything\n");
 503       return TRUE;
 504     }
 505
 506   if (transport->disconnected)
 507     {
 508       _dbus_verbose ("Not connected, not writing anything\n");
 509       return TRUE;
 510     }
 511
 512 #if 1
 513   _dbus_verbose ("do_writing(), have_messages = %d, fd = %d\n",
 514                  _dbus_connection_has_messages_to_send_unlocked (transport->connection),
 515                  socket_transport->fd);
 516 #endif
 517
 518   oom = FALSE;
 519   total = 0;
 520
 521   while (!transport->disconnected &&
 522          _dbus_connection_has_messages_to_send_unlocked (transport->connection))
 523     {
 524       int bytes_written;
 525       DBusMessage *message;
 526       const DBusString *header;
 527       const DBusString *body;
 528       int header_len, body_len;
 529       int total_bytes_to_write;
 530
 531       if (total > socket_transport->max_bytes_written_per_iteration)
 532         {
 533           _dbus_verbose ("%d bytes exceeds %d bytes written per iteration, returning\n",
 534                          total, socket_transport->max_bytes_written_per_iteration);
 535           goto out;
 536         }
 537
 538       message = _dbus_connection_get_message_to_send (transport->connection);
 539       _dbus_assert (message != NULL);
 540       dbus_message_lock (message);
 541
 542 #if 0
 543       _dbus_verbose ("writing message %p\n", message);
 544 #endif
 545
 546       _dbus_message_get_network_data (message,
 547                                       &header, &body);
 548
 549       header_len = _dbus_string_get_length (header);
 550       body_len = _dbus_string_get_length (body);
 551
 552       if (_dbus_auth_needs_encoding (transport->auth))
 553         {
 554           if (_dbus_string_get_length (&socket_transport->encoded_outgoing) == 0)
 555             {
 556               if (!_dbus_auth_encode_data (transport->auth,
 557                                            header, &socket_transport->encoded_outgoing))
 558                 {
 559                   oom = TRUE;
 560                   goto out;
 561                 }
 562
 563               if (!_dbus_auth_encode_data (transport->auth,
 564                                            body, &socket_transport->encoded_outgoing))
 565                 {
 566                   _dbus_string_set_length (&socket_transport->encoded_outgoing, 0);
 567                   oom = TRUE;
 568                   goto out;
 569                 }
 570             }
 571
 572           total_bytes_to_write = _dbus_string_get_length (&socket_transport->encoded_outgoing);
 573
 574 #if 0
 575           _dbus_verbose ("encoded message is %d bytes\n",
 576                          total_bytes_to_write);
 577 #endif
 578
 579           bytes_written =
 580             _dbus_write_socket (socket_transport->fd,
 581                                 &socket_transport->encoded_outgoing,
 582                                 socket_transport->message_bytes_written,
 583                                 total_bytes_to_write - socket_transport->message_bytes_written);
 584         }
 585       else
 586         {
 587           total_bytes_to_write = header_len + body_len;
 588
 589 #if 0
 590           _dbus_verbose ("message is %d bytes\n",
 591                          total_bytes_to_write);
 592 #endif
 593
 594           if (socket_transport->message_bytes_written < header_len)
 595             {
 596               bytes_written =
 597                 _dbus_write_socket_two (socket_transport->fd,
 598                                         header,
 599                                         socket_transport->message_bytes_written,
 600                                         header_len - socket_transport->message_bytes_written,
 601                                         body,
 602                                         0, body_len);
 603             }
 604           else
 605             {
 606               bytes_written =
 607                 _dbus_write_socket (socket_transport->fd,
 608                                     body,
 609                                     (socket_transport->message_bytes_written - header_len),
 610                                     body_len -
 611                                     (socket_transport->message_bytes_written - header_len));
 612             }
 613         }
 614
 615       if (bytes_written < 0)
 616         {
 617           /* EINTR already handled for us */
 618
 619           /* For some discussion of why we also ignore EPIPE here, see
 620            * http://lists.freedesktop.org/archives/dbus/2008-March/009526.html
 621            */
 622
 623           if (_dbus_get_is_errno_eagain_or_ewouldblock () || _dbus_get_is_errno_epipe ())
 624             goto out;
 625           else
 626             {
 627               _dbus_verbose ("Error writing to remote app: %s\n",
 628                              _dbus_strerror_from_errno ());
 629               do_io_error (transport);
 630               goto out;
 631             }
 632         }
 633       else
 634         {
 635           _dbus_verbose (" wrote %d bytes of %d\n", bytes_written,
 636                          total_bytes_to_write);
 637
 638           total += bytes_written;
 639           socket_transport->message_bytes_written += bytes_written;
 640
 641           _dbus_assert (socket_transport->message_bytes_written <=
 642                         total_bytes_to_write);
 643
 644           if (socket_transport->message_bytes_written == total_bytes_to_write)
 645             {
 646               socket_transport->message_bytes_written = 0;
 647               _dbus_string_set_length (&socket_transport->encoded_outgoing, 0);
 648               _dbus_string_compact (&socket_transport->encoded_outgoing, 2048);
 649
 650               _dbus_connection_message_sent (transport->connection,
 651                                              message);
 652             }
 653         }
 654     }
 655
 656  out:
 657   if (oom)
 658     return FALSE;
 659   else
 660     return TRUE;
 661 }
 662
 663 /* returns false on out-of-memory */
 664 static dbus_bool_t
 665 do_reading (DBusTransport *transport)
 666 {
 667   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 668   DBusString *buffer;
 669   int bytes_read;
 670   int total;
 671   dbus_bool_t oom;
 672
 673   _dbus_verbose ("%s: fd = %d\n", _DBUS_FUNCTION_NAME,
 674                  socket_transport->fd);
 675
 676   /* No messages without authentication! */
 677   if (!_dbus_transport_get_is_authenticated (transport))
 678     return TRUE;
 679
 680   oom = FALSE;
 681
 682   total = 0;
 683
 684  again:
 685
 686   /* See if we've exceeded max messages and need to disable reading */
 687   check_read_watch (transport);
 688
 689   if (total > socket_transport->max_bytes_read_per_iteration)
 690     {
 691       _dbus_verbose ("%d bytes exceeds %d bytes read per iteration, returning\n",
 692                      total, socket_transport->max_bytes_read_per_iteration);
 693       goto out;
 694     }
 695
 696   _dbus_assert (socket_transport->read_watch != NULL ||
 697                 transport->disconnected);
 698
 699   if (transport->disconnected)
 700     goto out;
 701
 702   if (!dbus_watch_get_enabled (socket_transport->read_watch))
 703     return TRUE;
 704
 705   if (_dbus_auth_needs_decoding (transport->auth))
 706     {
 707       if (_dbus_string_get_length (&socket_transport->encoded_incoming) > 0)
 708         bytes_read = _dbus_string_get_length (&socket_transport->encoded_incoming);
 709       else
 710         bytes_read = _dbus_read_socket (socket_transport->fd,
 711                                         &socket_transport->encoded_incoming,
 712                                         socket_transport->max_bytes_read_per_iteration);
 713
 714       _dbus_assert (_dbus_string_get_length (&socket_transport->encoded_incoming) ==
 715                     bytes_read);
 716
 717       if (bytes_read > 0)
 718         {
 719           int orig_len;
 720
 721           _dbus_message_loader_get_buffer (transport->loader,
 722                                            &buffer);
 723
 724           orig_len = _dbus_string_get_length (buffer);
 725
 726           if (!_dbus_auth_decode_data (transport->auth,
 727                                        &socket_transport->encoded_incoming,
 728                                        buffer))
 729             {
 730               _dbus_verbose ("Out of memory decoding incoming data\n");
 731               _dbus_message_loader_return_buffer (transport->loader,
 732                                               buffer,
 733                                               _dbus_string_get_length (buffer) - orig_len);
 734
 735               oom = TRUE;
 736               goto out;
 737             }
 738
 739           _dbus_message_loader_return_buffer (transport->loader,
 740                                               buffer,
 741                                               _dbus_string_get_length (buffer) - orig_len);
 742
 743           _dbus_string_set_length (&socket_transport->encoded_incoming, 0);
 744           _dbus_string_compact (&socket_transport->encoded_incoming, 2048);
 745         }
 746     }
 747   else
 748     {
 749       _dbus_message_loader_get_buffer (transport->loader,
 750                                        &buffer);
 751
 752       bytes_read = _dbus_read_socket (socket_transport->fd,
 753                                       buffer, socket_transport->max_bytes_read_per_iteration);
 754
 755       _dbus_message_loader_return_buffer (transport->loader,
 756                                           buffer,
 757                                           bytes_read < 0 ? 0 : bytes_read);
 758     }
 759
 760   if (bytes_read < 0)
 761     {
 762       /* EINTR already handled for us */
 763
 764       if (_dbus_get_is_errno_enomem ())
 765         {
 766           _dbus_verbose ("Out of memory in read()/do_reading()\n");
 767           oom = TRUE;
 768           goto out;
 769         }
 770       else if (_dbus_get_is_errno_eagain_or_ewouldblock ())
 771         goto out;
 772       else
 773         {
 774           _dbus_verbose ("Error reading from remote app: %s\n",
 775                          _dbus_strerror_from_errno ());
 776           do_io_error (transport);
 777           goto out;
 778         }
 779     }
 780   else if (bytes_read == 0)
 781     {
 782       _dbus_verbose ("Disconnected from remote app\n");
 783       do_io_error (transport);
 784       goto out;
 785     }
 786   else
 787     {
 788       _dbus_verbose (" read %d bytes\n", bytes_read);
 789
 790       total += bytes_read;
 791
 792       if (!_dbus_transport_queue_messages (transport))
 793         {
 794           oom = TRUE;
 795           _dbus_verbose (" out of memory when queueing messages we just read in the transport\n");
 796           goto out;
 797         }
 798
 799       /* Try reading more data until we get EAGAIN and return, or
 800        * exceed max bytes per iteration.  If in blocking mode of
 801        * course we'll block instead of returning.
 802        */
 803       goto again;
 804     }
 805
 806  out:
 807   if (oom)
 808     return FALSE;
 809   else
 810     return TRUE;
 811 }
 812
 813 static dbus_bool_t
 814 unix_error_with_read_to_come (DBusTransport *itransport,
 815                               DBusWatch     *watch,
 816                               unsigned int   flags)
 817 {
 818   DBusTransportSocket *transport = (DBusTransportSocket *) itransport;
 819
 820   if (!(flags & DBUS_WATCH_HANGUP || flags & DBUS_WATCH_ERROR))
 821     return FALSE;
 822
 823   /* If we have a read watch enabled ...
 824      we -might have data incoming ... => handle the HANGUP there */
 825   if (watch != transport->read_watch &&
 826       _dbus_watch_get_enabled (transport->read_watch))
 827     return FALSE;
 828
 829   return TRUE;
 830 }
 831
 832 static dbus_bool_t
 833 socket_handle_watch (DBusTransport *transport,
 834                    DBusWatch     *watch,
 835                    unsigned int   flags)
 836 {
 837   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 838
 839   _dbus_assert (watch == socket_transport->read_watch ||
 840                 watch == socket_transport->write_watch);
 841   _dbus_assert (watch != NULL);
 842
 843   /* If we hit an error here on a write watch, don't disconnect the transport yet because data can
 844    * still be in the buffer and do_reading may need several iteration to read
 845    * it all (because of its max_bytes_read_per_iteration limit).
 846    */
 847   if (!(flags & DBUS_WATCH_READABLE) && unix_error_with_read_to_come (transport, watch, flags))
 848     {
 849       _dbus_verbose ("Hang up or error on watch\n");
 850       _dbus_transport_disconnect (transport);
 851       return TRUE;
 852     }
 853
 854   if (watch == socket_transport->read_watch &&
 855       (flags & DBUS_WATCH_READABLE))
 856     {
 857       dbus_bool_t auth_finished;
 858 #if 1
 859       _dbus_verbose ("handling read watch %p flags = %x\n",
 860                      watch, flags);
 861 #endif
 862       if (!do_authentication (transport, TRUE, FALSE, &auth_finished))
 863         return FALSE;
 864
 865       /* We don't want to do a read immediately following
 866        * a successful authentication.  This is so we
 867        * have a chance to propagate the authentication
 868        * state further up.  Specifically, we need to
 869        * process any pending data from the auth object.
 870        */
 871       if (!auth_finished)
 872         {
 873           if (!do_reading (transport))
 874             {
 875               _dbus_verbose ("no memory to read\n");
 876               return FALSE;
 877             }
 878         }
 879       else
 880         {
 881           _dbus_verbose ("Not reading anything since we just completed the authentication\n");
 882         }
 883     }
 884   else if (watch == socket_transport->write_watch &&
 885            (flags & DBUS_WATCH_WRITABLE))
 886     {
 887 #if 1
 888       _dbus_verbose ("handling write watch, have_outgoing_messages = %d\n",
 889                      _dbus_connection_has_messages_to_send_unlocked (transport->connection));
 890 #endif
 891       if (!do_authentication (transport, FALSE, TRUE, NULL))
 892         return FALSE;
 893
 894       if (!do_writing (transport))
 895         {
 896           _dbus_verbose ("no memory to write\n");
 897           return FALSE;
 898         }
 899
 900       /* See if we still need the write watch */
 901       check_write_watch (transport);
 902     }
 903 #ifdef DBUS_ENABLE_VERBOSE_MODE
 904   else
 905     {
 906       if (watch == socket_transport->read_watch)
 907         _dbus_verbose ("asked to handle read watch with non-read condition 0x%x\n",
 908                        flags);
 909       else if (watch == socket_transport->write_watch)
 910         _dbus_verbose ("asked to handle write watch with non-write condition 0x%x\n",
 911                        flags);
 912       else
 913         _dbus_verbose ("asked to handle watch %p on fd %d that we don't recognize\n",
 914                        watch, dbus_watch_get_socket (watch));
 915     }
 916 #endif /* DBUS_ENABLE_VERBOSE_MODE */
 917
 918   return TRUE;
 919 }
 920
 921 static void
 922 socket_disconnect (DBusTransport *transport)
 923 {
 924   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 925
 926   _dbus_verbose ("%s\n", _DBUS_FUNCTION_NAME);
 927
 928   free_watches (transport);
 929
 930   _dbus_close_socket (socket_transport->fd, NULL);
 931   socket_transport->fd = -1;
 932 }
 933
 934 static dbus_bool_t
 935 socket_connection_set (DBusTransport *transport)
 936 {
 937   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 938
 939   _dbus_watch_set_handler (socket_transport->write_watch,
 940                            _dbus_connection_handle_watch,
 941                            transport->connection, NULL);
 942
 943   _dbus_watch_set_handler (socket_transport->read_watch,
 944                            _dbus_connection_handle_watch,
 945                            transport->connection, NULL);
 946
 947   if (!_dbus_connection_add_watch_unlocked (transport->connection,
 948                                             socket_transport->write_watch))
 949     return FALSE;
 950
 951   if (!_dbus_connection_add_watch_unlocked (transport->connection,
 952                                             socket_transport->read_watch))
 953     {
 954       _dbus_connection_remove_watch_unlocked (transport->connection,
 955                                               socket_transport->write_watch);
 956       return FALSE;
 957     }
 958
 959   check_read_watch (transport);
 960   check_write_watch (transport);
 961
 962   return TRUE;
 963 }
 964
 965 /**
 966  * @todo We need to have a way to wake up the select sleep if
 967  * a new iteration request comes in with a flag (read/write) that
 968  * we're not currently serving. Otherwise a call that just reads
 969  * could block a write call forever (if there are no incoming
 970  * messages).
 971  */
 972 static  void
 973 socket_do_iteration (DBusTransport *transport,
 974                    unsigned int   flags,
 975                    int            timeout_milliseconds)
 976 {
 977   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 978   DBusPollFD poll_fd;
 979   int poll_res;
 980   int poll_timeout;
 981
 982   _dbus_verbose (" iteration flags = %s%s timeout = %d read_watch = %p write_watch = %p fd = %d\n",
 983                  flags & DBUS_ITERATION_DO_READING ? "read" : "",
 984                  flags & DBUS_ITERATION_DO_WRITING ? "write" : "",
 985                  timeout_milliseconds,
 986                  socket_transport->read_watch,
 987                  socket_transport->write_watch,
 988                  socket_transport->fd);
 989
 990   /* the passed in DO_READING/DO_WRITING flags indicate whether to
 991    * read/write messages, but regardless of those we may need to block
 992    * for reading/writing to do auth.  But if we do reading for auth,
 993    * we don't want to read any messages yet if not given DO_READING.
 994    */
 995
 996   poll_fd.fd = socket_transport->fd;
 997   poll_fd.events = 0;
 998
 999   if (_dbus_transport_get_is_authenticated (transport))
1000     {
1001       /* This is kind of a hack; if we have stuff to write, then try
1002        * to avoid the poll. This is probably about a 5% speedup on an
1003        * echo client/server.
1004        *
1005        * If both reading and writing were requested, we want to avoid this
1006        * since it could have funky effects:
1007        *   - both ends spinning waiting for the other one to read
1008        *     data so they can finish writing
1009        *   - prioritizing all writing ahead of reading
1010        */
1011       if ((flags & DBUS_ITERATION_DO_WRITING) &&
1012           !(flags & (DBUS_ITERATION_DO_READING | DBUS_ITERATION_BLOCK)) &&
1013           !transport->disconnected &&
1014           _dbus_connection_has_messages_to_send_unlocked (transport->connection))
1015         {
1016           do_writing (transport);
1017
1018           if (transport->disconnected ||
1019               !_dbus_connection_has_messages_to_send_unlocked (transport->connection))
1020             goto out;
1021         }
1022
1023       /* If we get here, we decided to do the poll() after all */
1024       _dbus_assert (socket_transport->read_watch);
1025       if (flags & DBUS_ITERATION_DO_READING)
1026         poll_fd.events |= _DBUS_POLLIN;
1027
1028       _dbus_assert (socket_transport->write_watch);
1029       if (flags & DBUS_ITERATION_DO_WRITING)
1030         poll_fd.events |= _DBUS_POLLOUT;
1031     }
1032   else
1033     {
1034       DBusAuthState auth_state;
1035
1036       auth_state = _dbus_auth_do_work (transport->auth);
1037
1038       if (transport->receive_credentials_pending ||
1039           auth_state == DBUS_AUTH_STATE_WAITING_FOR_INPUT)
1040         poll_fd.events |= _DBUS_POLLIN;
1041
1042       if (transport->send_credentials_pending ||
1043           auth_state == DBUS_AUTH_STATE_HAVE_BYTES_TO_SEND)
1044         poll_fd.events |= _DBUS_POLLOUT;
1045     }
1046
1047   if (poll_fd.events)
1048     {
1049       if (flags & DBUS_ITERATION_BLOCK)
1050         poll_timeout = timeout_milliseconds;
1051       else
1052         poll_timeout = 0;
1053
1054       /* For blocking selects we drop the connection lock here
1055        * to avoid blocking out connection access during a potentially
1056        * indefinite blocking call. The io path is still protected
1057        * by the io_path_cond condvar, so we won't reenter this.
1058        */
1059       if (flags & DBUS_ITERATION_BLOCK)
1060         {
1061           _dbus_verbose ("unlock %s pre poll\n", _DBUS_FUNCTION_NAME);
1062           _dbus_connection_unlock (transport->connection);
1063         }
1064
1065     again:
1066       poll_res = _dbus_poll (&poll_fd, 1, poll_timeout);
1067
1068       if (poll_res < 0 && _dbus_get_is_errno_eintr ())
1069         goto again;
1070
1071       if (flags & DBUS_ITERATION_BLOCK)
1072         {
1073           _dbus_verbose ("lock %s post poll\n", _DBUS_FUNCTION_NAME);
1074           _dbus_connection_lock (transport->connection);
1075         }
1076
1077       if (poll_res >= 0)
1078         {
1079           if (poll_res == 0)
1080             poll_fd.revents = 0; /* some concern that posix does not guarantee this;
1081                                   * valgrind flags it as an error. though it probably
1082                                   * is guaranteed on linux at least.
1083                                   */
1084
1085           if (poll_fd.revents & _DBUS_POLLERR)
1086             do_io_error (transport);
1087           else
1088             {
1089               dbus_bool_t need_read = (poll_fd.revents & _DBUS_POLLIN) > 0;
1090               dbus_bool_t need_write = (poll_fd.revents & _DBUS_POLLOUT) > 0;
1091               dbus_bool_t authentication_completed;
1092
1093               _dbus_verbose ("in iteration, need_read=%d need_write=%d\n",
1094                              need_read, need_write);
1095               do_authentication (transport, need_read, need_write,
1096                                  &authentication_completed);
1097
1098               /* See comment in socket_handle_watch. */
1099               if (authentication_completed)
1100                 goto out;
1101
1102               if (need_read && (flags & DBUS_ITERATION_DO_READING))
1103                 do_reading (transport);
1104               if (need_write && (flags & DBUS_ITERATION_DO_WRITING))
1105                 do_writing (transport);
1106             }
1107         }
1108       else
1109         {
1110           _dbus_verbose ("Error from _dbus_poll(): %s\n",
1111                          _dbus_strerror_from_errno ());
1112         }
1113     }
1114
1115
1116  out:
1117   /* We need to install the write watch only if we did not
1118    * successfully write everything. Note we need to be careful that we
1119    * don't call check_write_watch *before* do_writing, since it's
1120    * inefficient to add the write watch, and we can avoid it most of
1121    * the time since we can write immediately.
1122    *
1123    * However, we MUST always call check_write_watch(); DBusConnection code
1124    * relies on the fact that running an iteration will notice that
1125    * messages are pending.
1126    */
1127   check_write_watch (transport);
1128
1129   _dbus_verbose (" ... leaving do_iteration()\n");
1130 }
1131
1132 static void
1133 socket_live_messages_changed (DBusTransport *transport)
1134 {
1135   /* See if we should look for incoming messages again */
1136   check_read_watch (transport);
1137 }
1138
1139
1140 static dbus_bool_t
1141 socket_get_socket_fd (DBusTransport *transport,
1142                       int           *fd_p)
1143 {
1144   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
1145
1146   *fd_p = socket_transport->fd;
1147
1148   return TRUE;
1149 }
1150
1151 static const DBusTransportVTable socket_vtable = {
1152   socket_finalize,
1153   socket_handle_watch,
1154   socket_disconnect,
1155   socket_connection_set,
1156   socket_do_iteration,
1157   socket_live_messages_changed,
1158   socket_get_socket_fd
1159 };
1160
1161 /**
1162  * Creates a new transport for the given socket file descriptor.  The file
1163  * descriptor must be nonblocking (use _dbus_set_fd_nonblocking() to
1164  * make it so). This function is shared by various transports that
1165  * boil down to a full duplex file descriptor.
1166  *
1167  * @param fd the file descriptor.
1168  * @param server_guid non-#NULL if this transport is on the server side of a connection
1169  * @param address the transport's address
1170  * @returns the new transport, or #NULL if no memory.
1171  */
1172 DBusTransport*
1173 _dbus_transport_new_for_socket (int               fd,
1174                                 const DBusString *server_guid,
1175                                 const DBusString *address)
1176 {
1177   DBusTransportSocket *socket_transport;
1178
1179   socket_transport = dbus_new0 (DBusTransportSocket, 1);
1180   if (socket_transport == NULL)
1181     return NULL;
1182
1183   if (!_dbus_string_init (&socket_transport->encoded_outgoing))
1184     goto failed_0;
1185
1186   if (!_dbus_string_init (&socket_transport->encoded_incoming))
1187     goto failed_1;
1188
1189   socket_transport->write_watch = _dbus_watch_new (fd,
1190                                                  DBUS_WATCH_WRITABLE,
1191                                                  FALSE,
1192                                                  NULL, NULL, NULL);
1193   if (socket_transport->write_watch == NULL)
1194     goto failed_2;
1195
1196   socket_transport->read_watch = _dbus_watch_new (fd,
1197                                                 DBUS_WATCH_READABLE,
1198                                                 FALSE,
1199                                                 NULL, NULL, NULL);
1200   if (socket_transport->read_watch == NULL)
1201     goto failed_3;
1202
1203   if (!_dbus_transport_init_base (&socket_transport->base,
1204                                   &socket_vtable,
1205                                   server_guid, address))
1206     goto failed_4;
1207
1208   socket_transport->fd = fd;
1209   socket_transport->message_bytes_written = 0;
1210
1211   /* These values should probably be tunable or something. */
1212   socket_transport->max_bytes_read_per_iteration = 2048;
1213   socket_transport->max_bytes_written_per_iteration = 2048;
1214
1215   return (DBusTransport*) socket_transport;
1216
1217  failed_4:
1218   _dbus_watch_unref (socket_transport->read_watch);
1219  failed_3:
1220   _dbus_watch_unref (socket_transport->write_watch);
1221  failed_2:
1222   _dbus_string_free (&socket_transport->encoded_incoming);
1223  failed_1:
1224   _dbus_string_free (&socket_transport->encoded_outgoing);
1225  failed_0:
1226   dbus_free (socket_transport);
1227   return NULL;
1228 }
1229
1230 /**
1231  * Creates a new transport for the given hostname and port.
1232  * If host is NULL, it will default to localhost
1233  *
1234  * @param host the host to connect to
1235  * @param port the port to connect to
1236  * @param family the address family to connect to
1237  * @param error location to store reason for failure.
1238  * @returns a new transport, or #NULL on failure.
1239  */
1240 DBusTransport*
1241 _dbus_transport_new_for_tcp_socket (const char     *host,
1242                                     const char     *port,
1243                                     const char     *family,
1244                                     DBusError      *error)
1245 {
1246   int fd;
1247   DBusTransport *transport;
1248   DBusString address;
1249
1250   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
1251
1252   if (!_dbus_string_init (&address))
1253     {
1254       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
1255       return NULL;
1256     }
1257
1258   if (host == NULL)
1259     host = "localhost";
1260
1261   if (!_dbus_string_append (&address, "tcp:"))
1262     goto error;
1263
1264   if (!_dbus_string_append (&address, "host=") ||
1265       !_dbus_string_append (&address, host))
1266     goto error;
1267
1268   if (!_dbus_string_append (&address, ",port=") ||
1269       !_dbus_string_append (&address, port))
1270     goto error;
1271
1272   if (family != NULL &&
1273       (!_dbus_string_append (&address, "family=") ||
1274        !_dbus_string_append (&address, family)))
1275     goto error;
1276
1277   fd = _dbus_connect_tcp_socket (host, port, family, error);
1278   if (fd < 0)
1279     {
1280       _DBUS_ASSERT_ERROR_IS_SET (error);
1281       _dbus_string_free (&address);
1282       return NULL;
1283     }
1284
1285   _dbus_fd_set_close_on_exec (fd);
1286
1287   _dbus_verbose ("Successfully connected to tcp socket %s:%s\n",
1288                  host, port);
1289
1290   transport = _dbus_transport_new_for_socket (fd, NULL, &address);
1291   if (transport == NULL)
1292     {
1293       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
1294       _dbus_close_socket (fd, NULL);
1295       _dbus_string_free (&address);
1296       fd = -1;
1297     }
1298
1299   _dbus_string_free (&address);
1300
1301   return transport;
1302
1303 error:
1304   _dbus_string_free (&address);
1305   dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
1306   return NULL;
1307 }
1308
1309 /**
1310  * Opens a TCP socket transport.
1311  *
1312  * @param entry the address entry to try opening as a tcp transport.
1313  * @param transport_p return location for the opened transport
1314  * @param error error to be set
1315  * @returns result of the attempt
1316  */
1317 DBusTransportOpenResult
1318 _dbus_transport_open_socket(DBusAddressEntry  *entry,
1319                             DBusTransport    **transport_p,
1320                             DBusError         *error)
1321 {
1322   const char *method;
1323
1324   method = dbus_address_entry_get_method (entry);
1325   _dbus_assert (method != NULL);
1326
1327   if (strcmp (method, "tcp") == 0)
1328     {
1329       const char *host = dbus_address_entry_get_value (entry, "host");
1330       const char *port = dbus_address_entry_get_value (entry, "port");
1331       const char *family = dbus_address_entry_get_value (entry, "family");
1332
1333       if (port == NULL)
1334         {
1335           _dbus_set_bad_address (error, "tcp", "port", NULL);
1336           return DBUS_TRANSPORT_OPEN_BAD_ADDRESS;
1337         }
1338
1339       *transport_p = _dbus_transport_new_for_tcp_socket (host, port, family, error);
1340       if (*transport_p == NULL)
1341         {
1342           _DBUS_ASSERT_ERROR_IS_SET (error);
1343           return DBUS_TRANSPORT_OPEN_DID_NOT_CONNECT;
1344         }
1345       else
1346         {
1347           _DBUS_ASSERT_ERROR_IS_CLEAR (error);
1348           return DBUS_TRANSPORT_OPEN_OK;
1349         }
1350     }
1351   else
1352     {
1353       _DBUS_ASSERT_ERROR_IS_CLEAR (error);
1354       return DBUS_TRANSPORT_OPEN_NOT_HANDLED;
1355     }
1356 }
1357
1358 /** @} */
1359