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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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           if (_dbus_get_is_errno_eagain_or_ewouldblock ())
 620             goto out;
 621           else
 622             {
 623               _dbus_verbose ("Error writing to remote app: %s\n",
 624                              _dbus_strerror_from_errno ());
 625               do_io_error (transport);
 626               goto out;
 627             }
 628         }
 629       else
 630         {
 631           _dbus_verbose (" wrote %d bytes of %d\n", bytes_written,
 632                          total_bytes_to_write);
 633
 634           total += bytes_written;
 635           socket_transport->message_bytes_written += bytes_written;
 636
 637           _dbus_assert (socket_transport->message_bytes_written <=
 638                         total_bytes_to_write);
 639
 640           if (socket_transport->message_bytes_written == total_bytes_to_write)
 641             {
 642               socket_transport->message_bytes_written = 0;
 643               _dbus_string_set_length (&socket_transport->encoded_outgoing, 0);
 644               _dbus_string_compact (&socket_transport->encoded_outgoing, 2048);
 645
 646               _dbus_connection_message_sent (transport->connection,
 647                                              message);
 648             }
 649         }
 650     }
 651
 652  out:
 653   if (oom)
 654     return FALSE;
 655   else
 656     return TRUE;
 657 }
 658
 659 /* returns false on out-of-memory */
 660 static dbus_bool_t
 661 do_reading (DBusTransport *transport)
 662 {
 663   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 664   DBusString *buffer;
 665   int bytes_read;
 666   int total;
 667   dbus_bool_t oom;
 668
 669   _dbus_verbose ("%s: fd = %d\n", _DBUS_FUNCTION_NAME,
 670                  socket_transport->fd);
 671
 672   /* No messages without authentication! */
 673   if (!_dbus_transport_get_is_authenticated (transport))
 674     return TRUE;
 675
 676   oom = FALSE;
 677
 678   total = 0;
 679
 680  again:
 681
 682   /* See if we've exceeded max messages and need to disable reading */
 683   check_read_watch (transport);
 684
 685   if (total > socket_transport->max_bytes_read_per_iteration)
 686     {
 687       _dbus_verbose ("%d bytes exceeds %d bytes read per iteration, returning\n",
 688                      total, socket_transport->max_bytes_read_per_iteration);
 689       goto out;
 690     }
 691
 692   _dbus_assert (socket_transport->read_watch != NULL ||
 693                 transport->disconnected);
 694
 695   if (transport->disconnected)
 696     goto out;
 697
 698   if (!dbus_watch_get_enabled (socket_transport->read_watch))
 699     return TRUE;
 700
 701   if (_dbus_auth_needs_decoding (transport->auth))
 702     {
 703       if (_dbus_string_get_length (&socket_transport->encoded_incoming) > 0)
 704         bytes_read = _dbus_string_get_length (&socket_transport->encoded_incoming);
 705       else
 706         bytes_read = _dbus_read_socket (socket_transport->fd,
 707                                         &socket_transport->encoded_incoming,
 708                                         socket_transport->max_bytes_read_per_iteration);
 709
 710       _dbus_assert (_dbus_string_get_length (&socket_transport->encoded_incoming) ==
 711                     bytes_read);
 712
 713       if (bytes_read > 0)
 714         {
 715           int orig_len;
 716
 717           _dbus_message_loader_get_buffer (transport->loader,
 718                                            &buffer);
 719
 720           orig_len = _dbus_string_get_length (buffer);
 721
 722           if (!_dbus_auth_decode_data (transport->auth,
 723                                        &socket_transport->encoded_incoming,
 724                                        buffer))
 725             {
 726               _dbus_verbose ("Out of memory decoding incoming data\n");
 727               oom = TRUE;
 728               goto out;
 729             }
 730
 731           _dbus_message_loader_return_buffer (transport->loader,
 732                                               buffer,
 733                                               _dbus_string_get_length (buffer) - orig_len);
 734
 735           _dbus_string_set_length (&socket_transport->encoded_incoming, 0);
 736           _dbus_string_compact (&socket_transport->encoded_incoming, 2048);
 737         }
 738     }
 739   else
 740     {
 741       _dbus_message_loader_get_buffer (transport->loader,
 742                                        &buffer);
 743
 744       bytes_read = _dbus_read_socket (socket_transport->fd,
 745                                       buffer, socket_transport->max_bytes_read_per_iteration);
 746
 747       _dbus_message_loader_return_buffer (transport->loader,
 748                                           buffer,
 749                                           bytes_read < 0 ? 0 : bytes_read);
 750     }
 751
 752   if (bytes_read < 0)
 753     {
 754       /* EINTR already handled for us */
 755
 756       if (_dbus_get_is_errno_enomem ())
 757         {
 758           _dbus_verbose ("Out of memory in read()/do_reading()\n");
 759           oom = TRUE;
 760           goto out;
 761         }
 762       else if (_dbus_get_is_errno_eagain_or_ewouldblock ())
 763         goto out;
 764       else
 765         {
 766           _dbus_verbose ("Error reading from remote app: %s\n",
 767                          _dbus_strerror_from_errno ());
 768           do_io_error (transport);
 769           goto out;
 770         }
 771     }
 772   else if (bytes_read == 0)
 773     {
 774       _dbus_verbose ("Disconnected from remote app\n");
 775       do_io_error (transport);
 776       goto out;
 777     }
 778   else
 779     {
 780       _dbus_verbose (" read %d bytes\n", bytes_read);
 781
 782       total += bytes_read;
 783
 784       if (!_dbus_transport_queue_messages (transport))
 785         {
 786           oom = TRUE;
 787           _dbus_verbose (" out of memory when queueing messages we just read in the transport\n");
 788           goto out;
 789         }
 790
 791       /* Try reading more data until we get EAGAIN and return, or
 792        * exceed max bytes per iteration.  If in blocking mode of
 793        * course we'll block instead of returning.
 794        */
 795       goto again;
 796     }
 797
 798  out:
 799   if (oom)
 800     return FALSE;
 801   else
 802     return TRUE;
 803 }
 804
 805 static dbus_bool_t
 806 socket_handle_watch (DBusTransport *transport,
 807                    DBusWatch     *watch,
 808                    unsigned int   flags)
 809 {
 810   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 811
 812   _dbus_assert (watch == socket_transport->read_watch ||
 813                 watch == socket_transport->write_watch);
 814   _dbus_assert (watch != NULL);
 815
 816   /* Disconnect in case of an error.  In case of hangup do not
 817    * disconnect the transport because data can still be in the buffer
 818    * and do_reading may need several iteration to read it all (because
 819    * of its max_bytes_read_per_iteration limit).  The condition where
 820    * flags == HANGUP (without READABLE) probably never happen in fact.
 821    */
 822   if ((flags & DBUS_WATCH_ERROR) ||
 823       ((flags & DBUS_WATCH_HANGUP) && !(flags & DBUS_WATCH_READABLE)))
 824     {
 825       _dbus_verbose ("Hang up or error on watch\n");
 826       _dbus_transport_disconnect (transport);
 827       return TRUE;
 828     }
 829
 830   if (watch == socket_transport->read_watch &&
 831       (flags & DBUS_WATCH_READABLE))
 832     {
 833       dbus_bool_t auth_finished;
 834 #if 1
 835       _dbus_verbose ("handling read watch %p flags = %x\n",
 836                      watch, flags);
 837 #endif
 838       if (!do_authentication (transport, TRUE, FALSE, &auth_finished))
 839         return FALSE;
 840
 841       /* We don't want to do a read immediately following
 842        * a successful authentication.  This is so we
 843        * have a chance to propagate the authentication
 844        * state further up.  Specifically, we need to
 845        * process any pending data from the auth object.
 846        */
 847       if (!auth_finished)
 848         {
 849           if (!do_reading (transport))
 850             {
 851               _dbus_verbose ("no memory to read\n");
 852               return FALSE;
 853             }
 854         }
 855       else
 856         {
 857           _dbus_verbose ("Not reading anything since we just completed the authentication\n");
 858         }
 859     }
 860   else if (watch == socket_transport->write_watch &&
 861            (flags & DBUS_WATCH_WRITABLE))
 862     {
 863 #if 1
 864       _dbus_verbose ("handling write watch, have_outgoing_messages = %d\n",
 865                      _dbus_connection_has_messages_to_send_unlocked (transport->connection));
 866 #endif
 867       if (!do_authentication (transport, FALSE, TRUE, NULL))
 868         return FALSE;
 869
 870       if (!do_writing (transport))
 871         {
 872           _dbus_verbose ("no memory to write\n");
 873           return FALSE;
 874         }
 875
 876       /* See if we still need the write watch */
 877       check_write_watch (transport);
 878     }
 879 #ifdef DBUS_ENABLE_VERBOSE_MODE
 880   else
 881     {
 882       if (watch == socket_transport->read_watch)
 883         _dbus_verbose ("asked to handle read watch with non-read condition 0x%x\n",
 884                        flags);
 885       else if (watch == socket_transport->write_watch)
 886         _dbus_verbose ("asked to handle write watch with non-write condition 0x%x\n",
 887                        flags);
 888       else
 889         _dbus_verbose ("asked to handle watch %p on fd %d that we don't recognize\n",
 890                        watch, dbus_watch_get_socket (watch));
 891     }
 892 #endif /* DBUS_ENABLE_VERBOSE_MODE */
 893
 894   return TRUE;
 895 }
 896
 897 static void
 898 socket_disconnect (DBusTransport *transport)
 899 {
 900   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 901
 902   _dbus_verbose ("%s\n", _DBUS_FUNCTION_NAME);
 903
 904   free_watches (transport);
 905
 906   _dbus_close_socket (socket_transport->fd, NULL);
 907   socket_transport->fd = -1;
 908 }
 909
 910 static dbus_bool_t
 911 socket_connection_set (DBusTransport *transport)
 912 {
 913   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 914
 915   _dbus_watch_set_handler (socket_transport->write_watch,
 916                            _dbus_connection_handle_watch,
 917                            transport->connection, NULL);
 918
 919   _dbus_watch_set_handler (socket_transport->read_watch,
 920                            _dbus_connection_handle_watch,
 921                            transport->connection, NULL);
 922
 923   if (!_dbus_connection_add_watch_unlocked (transport->connection,
 924                                             socket_transport->write_watch))
 925     return FALSE;
 926
 927   if (!_dbus_connection_add_watch_unlocked (transport->connection,
 928                                             socket_transport->read_watch))
 929     {
 930       _dbus_connection_remove_watch_unlocked (transport->connection,
 931                                               socket_transport->write_watch);
 932       return FALSE;
 933     }
 934
 935   check_read_watch (transport);
 936   check_write_watch (transport);
 937
 938   return TRUE;
 939 }
 940
 941 /**
 942  * @todo We need to have a way to wake up the select sleep if
 943  * a new iteration request comes in with a flag (read/write) that
 944  * we're not currently serving. Otherwise a call that just reads
 945  * could block a write call forever (if there are no incoming
 946  * messages).
 947  */
 948 static  void
 949 socket_do_iteration (DBusTransport *transport,
 950                    unsigned int   flags,
 951                    int            timeout_milliseconds)
 952 {
 953   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
 954   DBusPollFD poll_fd;
 955   int poll_res;
 956   int poll_timeout;
 957
 958   _dbus_verbose (" iteration flags = %s%s timeout = %d read_watch = %p write_watch = %p fd = %d\n",
 959                  flags & DBUS_ITERATION_DO_READING ? "read" : "",
 960                  flags & DBUS_ITERATION_DO_WRITING ? "write" : "",
 961                  timeout_milliseconds,
 962                  socket_transport->read_watch,
 963                  socket_transport->write_watch,
 964                  socket_transport->fd);
 965
 966   /* the passed in DO_READING/DO_WRITING flags indicate whether to
 967    * read/write messages, but regardless of those we may need to block
 968    * for reading/writing to do auth.  But if we do reading for auth,
 969    * we don't want to read any messages yet if not given DO_READING.
 970    */
 971
 972   poll_fd.fd = socket_transport->fd;
 973   poll_fd.events = 0;
 974
 975   if (_dbus_transport_get_is_authenticated (transport))
 976     {
 977       /* This is kind of a hack; if we have stuff to write, then try
 978        * to avoid the poll. This is probably about a 5% speedup on an
 979        * echo client/server.
 980        *
 981        * If both reading and writing were requested, we want to avoid this
 982        * since it could have funky effects:
 983        *   - both ends spinning waiting for the other one to read
 984        *     data so they can finish writing
 985        *   - prioritizing all writing ahead of reading
 986        */
 987       if ((flags & DBUS_ITERATION_DO_WRITING) &&
 988           !(flags & (DBUS_ITERATION_DO_READING | DBUS_ITERATION_BLOCK)) &&
 989           !transport->disconnected &&
 990           _dbus_connection_has_messages_to_send_unlocked (transport->connection))
 991         {
 992           do_writing (transport);
 993
 994           if (transport->disconnected ||
 995               !_dbus_connection_has_messages_to_send_unlocked (transport->connection))
 996             goto out;
 997         }
 998
 999       /* If we get here, we decided to do the poll() after all */
1000       _dbus_assert (socket_transport->read_watch);
1001       if (flags & DBUS_ITERATION_DO_READING)
1002         poll_fd.events |= _DBUS_POLLIN;
1003
1004       _dbus_assert (socket_transport->write_watch);
1005       if (flags & DBUS_ITERATION_DO_WRITING)
1006         poll_fd.events |= _DBUS_POLLOUT;
1007     }
1008   else
1009     {
1010       DBusAuthState auth_state;
1011
1012       auth_state = _dbus_auth_do_work (transport->auth);
1013
1014       if (transport->receive_credentials_pending ||
1015           auth_state == DBUS_AUTH_STATE_WAITING_FOR_INPUT)
1016         poll_fd.events |= _DBUS_POLLIN;
1017
1018       if (transport->send_credentials_pending ||
1019           auth_state == DBUS_AUTH_STATE_HAVE_BYTES_TO_SEND)
1020         poll_fd.events |= _DBUS_POLLOUT;
1021     }
1022
1023   if (poll_fd.events)
1024     {
1025       if (flags & DBUS_ITERATION_BLOCK)
1026         poll_timeout = timeout_milliseconds;
1027       else
1028         poll_timeout = 0;
1029
1030       /* For blocking selects we drop the connection lock here
1031        * to avoid blocking out connection access during a potentially
1032        * indefinite blocking call. The io path is still protected
1033        * by the io_path_cond condvar, so we won't reenter this.
1034        */
1035       if (flags & DBUS_ITERATION_BLOCK)
1036         {
1037           _dbus_verbose ("unlock %s pre poll\n", _DBUS_FUNCTION_NAME);
1038           _dbus_connection_unlock (transport->connection);
1039         }
1040
1041     again:
1042       poll_res = _dbus_poll (&poll_fd, 1, poll_timeout);
1043
1044       if (poll_res < 0 && _dbus_get_is_errno_eintr ())
1045         goto again;
1046
1047       if (flags & DBUS_ITERATION_BLOCK)
1048         {
1049           _dbus_verbose ("lock %s post poll\n", _DBUS_FUNCTION_NAME);
1050           _dbus_connection_lock (transport->connection);
1051         }
1052
1053       if (poll_res >= 0)
1054         {
1055           if (poll_res == 0)
1056             poll_fd.revents = 0; /* some concern that posix does not guarantee this;
1057                                   * valgrind flags it as an error. though it probably
1058                                   * is guaranteed on linux at least.
1059                                   */
1060
1061           if (poll_fd.revents & _DBUS_POLLERR)
1062             do_io_error (transport);
1063           else
1064             {
1065               dbus_bool_t need_read = (poll_fd.revents & _DBUS_POLLIN) > 0;
1066               dbus_bool_t need_write = (poll_fd.revents & _DBUS_POLLOUT) > 0;
1067               dbus_bool_t authentication_completed;
1068
1069               _dbus_verbose ("in iteration, need_read=%d need_write=%d\n",
1070                              need_read, need_write);
1071               do_authentication (transport, need_read, need_write,
1072                                  &authentication_completed);
1073
1074               /* See comment in socket_handle_watch. */
1075               if (authentication_completed)
1076                 goto out;
1077
1078               if (need_read && (flags & DBUS_ITERATION_DO_READING))
1079                 do_reading (transport);
1080               if (need_write && (flags & DBUS_ITERATION_DO_WRITING))
1081                 do_writing (transport);
1082             }
1083         }
1084       else
1085         {
1086           _dbus_verbose ("Error from _dbus_poll(): %s\n",
1087                          _dbus_strerror_from_errno ());
1088         }
1089     }
1090
1091
1092  out:
1093   /* We need to install the write watch only if we did not
1094    * successfully write everything. Note we need to be careful that we
1095    * don't call check_write_watch *before* do_writing, since it's
1096    * inefficient to add the write watch, and we can avoid it most of
1097    * the time since we can write immediately.
1098    *
1099    * However, we MUST always call check_write_watch(); DBusConnection code
1100    * relies on the fact that running an iteration will notice that
1101    * messages are pending.
1102    */
1103   check_write_watch (transport);
1104
1105   _dbus_verbose (" ... leaving do_iteration()\n");
1106 }
1107
1108 static void
1109 socket_live_messages_changed (DBusTransport *transport)
1110 {
1111   /* See if we should look for incoming messages again */
1112   check_read_watch (transport);
1113 }
1114
1115
1116 static dbus_bool_t
1117 socket_get_socket_fd (DBusTransport *transport,
1118                       int           *fd_p)
1119 {
1120   DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
1121
1122   *fd_p = socket_transport->fd;
1123
1124   return TRUE;
1125 }
1126
1127 static const DBusTransportVTable socket_vtable = {
1128   socket_finalize,
1129   socket_handle_watch,
1130   socket_disconnect,
1131   socket_connection_set,
1132   socket_do_iteration,
1133   socket_live_messages_changed,
1134   socket_get_socket_fd
1135 };
1136
1137 /**
1138  * Creates a new transport for the given socket file descriptor.  The file
1139  * descriptor must be nonblocking (use _dbus_set_fd_nonblocking() to
1140  * make it so). This function is shared by various transports that
1141  * boil down to a full duplex file descriptor.
1142  *
1143  * @param fd the file descriptor.
1144  * @param server_guid non-#NULL if this transport is on the server side of a connection
1145  * @param address the transport's address
1146  * @returns the new transport, or #NULL if no memory.
1147  */
1148 DBusTransport*
1149 _dbus_transport_new_for_socket (int               fd,
1150                                 const DBusString *server_guid,
1151                                 const DBusString *address)
1152 {
1153   DBusTransportSocket *socket_transport;
1154
1155   socket_transport = dbus_new0 (DBusTransportSocket, 1);
1156   if (socket_transport == NULL)
1157     return NULL;
1158
1159   if (!_dbus_string_init (&socket_transport->encoded_outgoing))
1160     goto failed_0;
1161
1162   if (!_dbus_string_init (&socket_transport->encoded_incoming))
1163     goto failed_1;
1164
1165   socket_transport->write_watch = _dbus_watch_new (fd,
1166                                                  DBUS_WATCH_WRITABLE,
1167                                                  FALSE,
1168                                                  NULL, NULL, NULL);
1169   if (socket_transport->write_watch == NULL)
1170     goto failed_2;
1171
1172   socket_transport->read_watch = _dbus_watch_new (fd,
1173                                                 DBUS_WATCH_READABLE,
1174                                                 FALSE,
1175                                                 NULL, NULL, NULL);
1176   if (socket_transport->read_watch == NULL)
1177     goto failed_3;
1178
1179   if (!_dbus_transport_init_base (&socket_transport->base,
1180                                   &socket_vtable,
1181                                   server_guid, address))
1182     goto failed_4;
1183
1184   socket_transport->fd = fd;
1185   socket_transport->message_bytes_written = 0;
1186
1187   /* These values should probably be tunable or something. */
1188   socket_transport->max_bytes_read_per_iteration = 2048;
1189   socket_transport->max_bytes_written_per_iteration = 2048;
1190
1191   return (DBusTransport*) socket_transport;
1192
1193  failed_4:
1194   _dbus_watch_unref (socket_transport->read_watch);
1195  failed_3:
1196   _dbus_watch_unref (socket_transport->write_watch);
1197  failed_2:
1198   _dbus_string_free (&socket_transport->encoded_incoming);
1199  failed_1:
1200   _dbus_string_free (&socket_transport->encoded_outgoing);
1201  failed_0:
1202   dbus_free (socket_transport);
1203   return NULL;
1204 }
1205
1206 /**
1207  * Creates a new transport for the given hostname and port.
1208  * If host is NULL, it will default to localhost
1209  *
1210  * @param host the host to connect to
1211  * @param port the port to connect to
1212  * @param family the address family to connect to
1213  * @param error location to store reason for failure.
1214  * @returns a new transport, or #NULL on failure.
1215  */
1216 DBusTransport*
1217 _dbus_transport_new_for_tcp_socket (const char     *host,
1218                                     const char     *port,
1219                                     const char     *family,
1220                                     DBusError      *error)
1221 {
1222   int fd;
1223   DBusTransport *transport;
1224   DBusString address;
1225
1226   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
1227
1228   if (!_dbus_string_init (&address))
1229     {
1230       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
1231       return NULL;
1232     }
1233
1234   if (host == NULL)
1235     host = "localhost";
1236
1237   if (!_dbus_string_append (&address, "tcp:"))
1238     goto error;
1239
1240   if (!_dbus_string_append (&address, "host=") ||
1241       !_dbus_string_append (&address, host))
1242     goto error;
1243
1244   if (!_dbus_string_append (&address, ",port=") ||
1245       !_dbus_string_append (&address, port))
1246     goto error;
1247
1248   if (family != NULL &&
1249       (!_dbus_string_append (&address, "family=") ||
1250        !_dbus_string_append (&address, family)))
1251     goto error;
1252
1253   fd = _dbus_connect_tcp_socket (host, port, family, error);
1254   if (fd < 0)
1255     {
1256       _DBUS_ASSERT_ERROR_IS_SET (error);
1257       _dbus_string_free (&address);
1258       return NULL;
1259     }
1260
1261   _dbus_fd_set_close_on_exec (fd);
1262
1263   _dbus_verbose ("Successfully connected to tcp socket %s:%s\n",
1264                  host, port);
1265
1266   transport = _dbus_transport_new_for_socket (fd, NULL, &address);
1267   if (transport == NULL)
1268     {
1269       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
1270       _dbus_close_socket (fd, NULL);
1271       _dbus_string_free (&address);
1272       fd = -1;
1273     }
1274
1275   _dbus_string_free (&address);
1276
1277   return transport;
1278
1279 error:
1280   _dbus_string_free (&address);
1281   dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
1282   return NULL;
1283 }
1284
1285 /**
1286  * Opens a TCP socket transport.
1287  *
1288  * @param entry the address entry to try opening as a tcp transport.
1289  * @param transport_p return location for the opened transport
1290  * @param error error to be set
1291  * @returns result of the attempt
1292  */
1293 DBusTransportOpenResult
1294 _dbus_transport_open_socket(DBusAddressEntry  *entry,
1295                             DBusTransport    **transport_p,
1296                             DBusError         *error)
1297 {
1298   const char *method;
1299
1300   method = dbus_address_entry_get_method (entry);
1301   _dbus_assert (method != NULL);
1302
1303   if (strcmp (method, "tcp") == 0)
1304     {
1305       const char *host = dbus_address_entry_get_value (entry, "host");
1306       const char *port = dbus_address_entry_get_value (entry, "port");
1307       const char *family = dbus_address_entry_get_value (entry, "family");
1308
1309       if (port == NULL)
1310         {
1311           _dbus_set_bad_address (error, "tcp", "port", NULL);
1312           return DBUS_TRANSPORT_OPEN_BAD_ADDRESS;
1313         }
1314
1315       *transport_p = _dbus_transport_new_for_tcp_socket (host, port, family, error);
1316       if (*transport_p == NULL)
1317         {
1318           _DBUS_ASSERT_ERROR_IS_SET (error);
1319           return DBUS_TRANSPORT_OPEN_DID_NOT_CONNECT;
1320         }
1321       else
1322         {
1323           _DBUS_ASSERT_ERROR_IS_CLEAR (error);
1324           return DBUS_TRANSPORT_OPEN_OK;
1325         }
1326     }
1327   else
1328     {
1329       _DBUS_ASSERT_ERROR_IS_CLEAR (error);
1330       return DBUS_TRANSPORT_OPEN_NOT_HANDLED;
1331     }
1332 }
1333
1334 /** @} */
1335