gio/gunixconnection.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright © 2009 Codethink Limited
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU Lesser General Public License as published
   7  * by the Free Software Foundation; either version 2 of the licence or (at
   8  * your option) any later version.
   9  *
  10  * See the included COPYING file for more information.
  11  *
  12  * Authors: Ryan Lortie <desrt@desrt.ca>
  13  */
  14
  15 #include "config.h"
  16
  17 #include "gunixconnection.h"
  18 #include "gnetworking.h"
  19 #include "gsocket.h"
  20 #include "gsocketcontrolmessage.h"
  21 #include "gunixcredentialsmessage.h"
  22 #include "gunixfdmessage.h"
  23 #include "glibintl.h"
  24
  25 #include <errno.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28
  29 /**
  30  * SECTION:gunixconnection
  31  * @title: GUnixConnection
  32  * @short_description: A UNIX domain GSocketConnection
  33  * @include: gio/gunixconnection.h
  34  * @see_also: #GSocketConnection.
  35  *
  36  * This is the subclass of #GSocketConnection that is created
  37  * for UNIX domain sockets.
  38  *
  39  * It contains functions to do some of the UNIX socket specific
  40  * functionality like passing file descriptors.
  41  *
  42  * Note that <filename>&lt;gio/gunixconnection.h&gt;</filename> belongs to
  43  * the UNIX-specific GIO interfaces, thus you have to use the
  44  * <filename>gio-unix-2.0.pc</filename> pkg-config file when using it.
  45  *
  46  * Since: 2.22
  47  */
  48
  49 G_DEFINE_TYPE_WITH_CODE (GUnixConnection, g_unix_connection,
  50                          G_TYPE_SOCKET_CONNECTION,
  51   g_socket_connection_factory_register_type (g_define_type_id,
  52                                              G_SOCKET_FAMILY_UNIX,
  53                                              G_SOCKET_TYPE_STREAM,
  54                                              G_SOCKET_PROTOCOL_DEFAULT);
  55                          );
  56
  57 /**
  58  * g_unix_connection_send_fd:
  59  * @connection: a #GUnixConnection
  60  * @fd: a file descriptor
  61  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
  62  * @error: (allow-none): #GError for error reporting, or %NULL to ignore.
  63  *
  64  * Passes a file descriptor to the receiving side of the
  65  * connection. The receiving end has to call g_unix_connection_receive_fd()
  66  * to accept the file descriptor.
  67  *
  68  * As well as sending the fd this also writes a single byte to the
  69  * stream, as this is required for fd passing to work on some
  70  * implementations.
  71  *
  72  * Returns: a %TRUE on success, %NULL on error.
  73  *
  74  * Since: 2.22
  75  */
  76 gboolean
  77 g_unix_connection_send_fd (GUnixConnection  *connection,
  78                            gint              fd,
  79                            GCancellable     *cancellable,
  80                            GError          **error)
  81 {
  82   GSocketControlMessage *scm;
  83   GSocket *socket;
  84
  85   g_return_val_if_fail (G_IS_UNIX_CONNECTION (connection), FALSE);
  86   g_return_val_if_fail (fd >= 0, FALSE);
  87
  88   scm = g_unix_fd_message_new ();
  89
  90   if (!g_unix_fd_message_append_fd (G_UNIX_FD_MESSAGE (scm), fd, error))
  91     {
  92       g_object_unref (scm);
  93       return FALSE;
  94     }
  95
  96   g_object_get (connection, "socket", &socket, NULL);
  97   if (g_socket_send_message (socket, NULL, NULL, 0, &scm, 1, 0, cancellable, error) != 1)
  98     /* XXX could it 'fail' with zero? */
  99     {
 100       g_object_unref (socket);
 101       g_object_unref (scm);
 102
 103       return FALSE;
 104     }
 105
 106   g_object_unref (socket);
 107   g_object_unref (scm);
 108
 109   return TRUE;
 110 }
 111
 112 /**
 113  * g_unix_connection_receive_fd:
 114  * @connection: a #GUnixConnection
 115  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 116  * @error: (allow-none): #GError for error reporting, or %NULL to ignore
 117  *
 118  * Receives a file descriptor from the sending end of the connection.
 119  * The sending end has to call g_unix_connection_send_fd() for this
 120  * to work.
 121  *
 122  * As well as reading the fd this also reads a single byte from the
 123  * stream, as this is required for fd passing to work on some
 124  * implementations.
 125  *
 126  * Returns: a file descriptor on success, -1 on error.
 127  *
 128  * Since: 2.22
 129  **/
 130 gint
 131 g_unix_connection_receive_fd (GUnixConnection  *connection,
 132                               GCancellable     *cancellable,
 133                               GError          **error)
 134 {
 135   GSocketControlMessage **scms;
 136   gint *fds, nfd, fd, nscm;
 137   GUnixFDMessage *fdmsg;
 138   GSocket *socket;
 139
 140   g_return_val_if_fail (G_IS_UNIX_CONNECTION (connection), -1);
 141
 142   g_object_get (connection, "socket", &socket, NULL);
 143   if (g_socket_receive_message (socket, NULL, NULL, 0,
 144                                 &scms, &nscm, NULL, cancellable, error) != 1)
 145     /* XXX it _could_ 'fail' with zero. */
 146     {
 147       g_object_unref (socket);
 148
 149       return -1;
 150     }
 151
 152   g_object_unref (socket);
 153
 154   if (nscm != 1)
 155     {
 156       gint i;
 157
 158       g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
 159                    _("Expecting 1 control message, got %d"), nscm);
 160
 161       for (i = 0; i < nscm; i++)
 162         g_object_unref (scms[i]);
 163
 164       g_free (scms);
 165
 166       return -1;
 167     }
 168
 169   if (!G_IS_UNIX_FD_MESSAGE (scms[0]))
 170     {
 171       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
 172                            _("Unexpected type of ancillary data"));
 173       g_object_unref (scms[0]);
 174       g_free (scms);
 175
 176       return -1;
 177     }
 178
 179   fdmsg = G_UNIX_FD_MESSAGE (scms[0]);
 180   g_free (scms);
 181
 182   fds = g_unix_fd_message_steal_fds (fdmsg, &nfd);
 183   g_object_unref (fdmsg);
 184
 185   if (nfd != 1)
 186     {
 187       gint i;
 188
 189       g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
 190                    _("Expecting one fd, but got %d\n"), nfd);
 191
 192       for (i = 0; i < nfd; i++)
 193         close (fds[i]);
 194
 195       g_free (fds);
 196
 197       return -1;
 198     }
 199
 200   fd = *fds;
 201   g_free (fds);
 202
 203   if (fd < 0)
 204     {
 205       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
 206                            _("Received invalid fd"));
 207       fd = -1;
 208     }
 209
 210   return fd;
 211 }
 212
 213 static void
 214 g_unix_connection_init (GUnixConnection *connection)
 215 {
 216 }
 217
 218 static void
 219 g_unix_connection_class_init (GUnixConnectionClass *class)
 220 {
 221 }
 222
 223 /* TODO: Other stuff we might want to add are:
 224 void                    g_unix_connection_send_fd_async                 (GUnixConnection      *connection,
 225                                                                          gint                  fd,
 226                                                                          gboolean              close,
 227                                                                          gint                  io_priority,
 228                                                                          GAsyncReadyCallback   callback,
 229                                                                          gpointer              user_data);
 230 gboolean                g_unix_connection_send_fd_finish                (GUnixConnection      *connection,
 231                                                                          GError              **error);
 232
 233 gboolean                g_unix_connection_send_fds                      (GUnixConnection      *connection,
 234                                                                          gint                 *fds,
 235                                                                          gint                  nfds,
 236                                                                          GError              **error);
 237 void                    g_unix_connection_send_fds_async                (GUnixConnection      *connection,
 238                                                                          gint                 *fds,
 239                                                                          gint                  nfds,
 240                                                                          gint                  io_priority,
 241                                                                          GAsyncReadyCallback   callback,
 242                                                                          gpointer              user_data);
 243 gboolean                g_unix_connection_send_fds_finish               (GUnixConnection      *connection,
 244                                                                          GError              **error);
 245
 246 void                    g_unix_connection_receive_fd_async              (GUnixConnection      *connection,
 247                                                                          gint                  io_priority,
 248                                                                          GAsyncReadyCallback   callback,
 249                                                                          gpointer              user_data);
 250 gint                    g_unix_connection_receive_fd_finish             (GUnixConnection      *connection,
 251                                                                          GError              **error);
 252
 253
 254 gboolean                g_unix_connection_send_fake_credentials         (GUnixConnection      *connection,
 255                                                                          guint64               pid,
 256                                                                          guint64               uid,
 257                                                                          guint64               gid,
 258                                                                          GError              **error);
 259 void                    g_unix_connection_send_fake_credentials_async   (GUnixConnection      *connection,
 260                                                                          guint64               pid,
 261                                                                          guint64               uid,
 262                                                                          guint64               gid,
 263                                                                          gint                  io_priority,
 264                                                                          GAsyncReadyCallback   callback,
 265                                                                          gpointer              user_data);
 266 gboolean                g_unix_connection_send_fake_credentials_finish  (GUnixConnection      *connection,
 267                                                                          GError              **error);
 268
 269 gboolean                g_unix_connection_create_pair                   (GUnixConnection     **one,
 270                                                                          GUnixConnection     **two,
 271                                                                          GError              **error);
 272 */
 273
 274
 275 /**
 276  * g_unix_connection_send_credentials:
 277  * @connection: A #GUnixConnection.
 278  * @cancellable: (allow-none): A #GCancellable or %NULL.
 279  * @error: Return location for error or %NULL.
 280  *
 281  * Passes the credentials of the current user the receiving side
 282  * of the connection. The receiving end has to call
 283  * g_unix_connection_receive_credentials() (or similar) to accept the
 284  * credentials.
 285  *
 286  * As well as sending the credentials this also writes a single NUL
 287  * byte to the stream, as this is required for credentials passing to
 288  * work on some implementations.
 289  *
 290  * Other ways to exchange credentials with a foreign peer includes the
 291  * #GUnixCredentialsMessage type and g_socket_get_credentials() function.
 292  *
 293  * Returns: %TRUE on success, %FALSE if @error is set.
 294  *
 295  * Since: 2.26
 296  */
 297 gboolean
 298 g_unix_connection_send_credentials (GUnixConnection      *connection,
 299                                     GCancellable         *cancellable,
 300                                     GError              **error)
 301 {
 302   GCredentials *credentials;
 303   GSocketControlMessage *scm;
 304   GSocket *socket;
 305   gboolean ret;
 306   GOutputVector vector;
 307   guchar nul_byte[1] = {'\0'};
 308   gint num_messages;
 309
 310   g_return_val_if_fail (G_IS_UNIX_CONNECTION (connection), FALSE);
 311   g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
 312
 313   ret = FALSE;
 314
 315   credentials = g_credentials_new ();
 316
 317   vector.buffer = &nul_byte;
 318   vector.size = 1;
 319
 320   if (g_unix_credentials_message_is_supported ())
 321     {
 322       scm = g_unix_credentials_message_new_with_credentials (credentials);
 323       num_messages = 1;
 324     }
 325   else
 326     {
 327       scm = NULL;
 328       num_messages = 0;
 329     }
 330
 331   g_object_get (connection, "socket", &socket, NULL);
 332   if (g_socket_send_message (socket,
 333                              NULL, /* address */
 334                              &vector,
 335                              1,
 336                              &scm,
 337                              num_messages,
 338                              G_SOCKET_MSG_NONE,
 339                              cancellable,
 340                              error) != 1)
 341     {
 342       g_prefix_error (error, _("Error sending credentials: "));
 343       goto out;
 344     }
 345
 346   ret = TRUE;
 347
 348  out:
 349   g_object_unref (socket);
 350   if (scm != NULL)
 351     g_object_unref (scm);
 352   g_object_unref (credentials);
 353   return ret;
 354 }
 355
 356 static void
 357 send_credentials_async_thread (GTask         *task,
 358                                gpointer       source_object,
 359                                gpointer       task_data,
 360                                GCancellable  *cancellable)
 361 {
 362   GError *error = NULL;
 363
 364   if (g_unix_connection_send_credentials (G_UNIX_CONNECTION (source_object),
 365                                           cancellable,
 366                                           &error))
 367     g_task_return_boolean (task, TRUE);
 368   else
 369     g_task_return_error (task, error);
 370   g_object_unref (task);
 371 }
 372
 373 /**
 374  * g_unix_connection_send_credentials_async:
 375  * @connection: A #GUnixConnection.
 376  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
 377  * @callback: (scope async): a #GAsyncReadyCallback to call when the request is satisfied
 378  * @user_data: (closure): the data to pass to callback function
 379  *
 380  * Asynchronously send credentials.
 381  *
 382  * For more details, see g_unix_connection_send_credentials() which is
 383  * the synchronous version of this call.
 384  *
 385  * When the operation is finished, @callback will be called. You can then call
 386  * g_unix_connection_send_credentials_finish() to get the result of the operation.
 387  *
 388  * Since: 2.32
 389  **/
 390 void
 391 g_unix_connection_send_credentials_async (GUnixConnection      *connection,
 392                                           GCancellable         *cancellable,
 393                                           GAsyncReadyCallback   callback,
 394                                           gpointer              user_data)
 395 {
 396   GTask *task;
 397
 398   task = g_task_new (connection, cancellable, callback, user_data);
 399
 400   g_task_run_in_thread (task, send_credentials_async_thread);
 401 }
 402
 403 /**
 404  * g_unix_connection_send_credentials_finish:
 405  * @connection: A #GUnixConnection.
 406  * @result: a #GAsyncResult.
 407  * @error: a #GError, or %NULL
 408  *
 409  * Finishes an asynchronous send credentials operation started with
 410  * g_unix_connection_send_credentials_async().
 411  *
 412  * Returns: %TRUE if the operation was successful, otherwise %FALSE.
 413  *
 414  * Since: 2.32
 415  **/
 416 gboolean
 417 g_unix_connection_send_credentials_finish (GUnixConnection *connection,
 418                                            GAsyncResult    *result,
 419                                            GError         **error)
 420 {
 421   g_return_val_if_fail (g_task_is_valid (result, connection), FALSE);
 422
 423   return g_task_propagate_boolean (G_TASK (result), error);
 424 }
 425
 426 /**
 427  * g_unix_connection_receive_credentials:
 428  * @connection: A #GUnixConnection.
 429  * @cancellable: (allow-none): A #GCancellable or %NULL.
 430  * @error: Return location for error or %NULL.
 431  *
 432  * Receives credentials from the sending end of the connection.  The
 433  * sending end has to call g_unix_connection_send_credentials() (or
 434  * similar) for this to work.
 435  *
 436  * As well as reading the credentials this also reads (and discards) a
 437  * single byte from the stream, as this is required for credentials
 438  * passing to work on some implementations.
 439  *
 440  * Other ways to exchange credentials with a foreign peer includes the
 441  * #GUnixCredentialsMessage type and g_socket_get_credentials() function.
 442  *
 443  * Returns: (transfer full): Received credentials on success (free with
 444  * g_object_unref()), %NULL if @error is set.
 445  *
 446  * Since: 2.26
 447  */
 448 GCredentials *
 449 g_unix_connection_receive_credentials (GUnixConnection      *connection,
 450                                        GCancellable         *cancellable,
 451                                        GError              **error)
 452 {
 453   GCredentials *ret;
 454   GSocketControlMessage **scms;
 455   gint nscm;
 456   GSocket *socket;
 457   gint n;
 458   gssize num_bytes_read;
 459 #ifdef __linux__
 460   gboolean turn_off_so_passcreds;
 461 #endif
 462
 463   g_return_val_if_fail (G_IS_UNIX_CONNECTION (connection), NULL);
 464   g_return_val_if_fail (error == NULL || *error == NULL, NULL);
 465
 466   ret = NULL;
 467   scms = NULL;
 468
 469   g_object_get (connection, "socket", &socket, NULL);
 470
 471   /* On Linux, we need to turn on SO_PASSCRED if it isn't enabled
 472    * already. We also need to turn it off when we're done.  See
 473    * #617483 for more discussion.
 474    */
 475 #ifdef __linux__
 476   {
 477     gint opt_val;
 478
 479     turn_off_so_passcreds = FALSE;
 480     opt_val = 0;
 481     if (!g_socket_get_option (socket,
 482                               SOL_SOCKET,
 483                               SO_PASSCRED,
 484                               &opt_val,
 485                               NULL))
 486       {
 487         g_set_error (error,
 488                      G_IO_ERROR,
 489                      g_io_error_from_errno (errno),
 490                      _("Error checking if SO_PASSCRED is enabled for socket: %s"),
 491                      strerror (errno));
 492         goto out;
 493       }
 494     if (opt_val == 0)
 495       {
 496         if (!g_socket_set_option (socket,
 497                                   SOL_SOCKET,
 498                                   SO_PASSCRED,
 499                                   TRUE,
 500                                   NULL))
 501           {
 502             g_set_error (error,
 503                          G_IO_ERROR,
 504                          g_io_error_from_errno (errno),
 505                          _("Error enabling SO_PASSCRED: %s"),
 506                          strerror (errno));
 507             goto out;
 508           }
 509         turn_off_so_passcreds = TRUE;
 510       }
 511   }
 512 #endif
 513
 514   g_type_ensure (G_TYPE_UNIX_CREDENTIALS_MESSAGE);
 515   num_bytes_read = g_socket_receive_message (socket,
 516                                              NULL, /* GSocketAddress **address */
 517                                              NULL,
 518                                              0,
 519                                              &scms,
 520                                              &nscm,
 521                                              NULL,
 522                                              cancellable,
 523                                              error);
 524   if (num_bytes_read != 1)
 525     {
 526       /* Handle situation where g_socket_receive_message() returns
 527        * 0 bytes and not setting @error
 528        */
 529       if (num_bytes_read == 0 && error != NULL && *error == NULL)
 530         {
 531           g_set_error_literal (error,
 532                                G_IO_ERROR,
 533                                G_IO_ERROR_FAILED,
 534                                _("Expecting to read a single byte for receiving credentials but read zero bytes"));
 535         }
 536       goto out;
 537     }
 538
 539   if (g_unix_credentials_message_is_supported () &&
 540       /* Fall back on get_credentials if the other side didn't send the credentials */
 541       nscm > 0)
 542     {
 543       if (nscm != 1)
 544         {
 545           g_set_error (error,
 546                        G_IO_ERROR,
 547                        G_IO_ERROR_FAILED,
 548                        _("Expecting 1 control message, got %d"),
 549                        nscm);
 550           goto out;
 551         }
 552
 553       if (!G_IS_UNIX_CREDENTIALS_MESSAGE (scms[0]))
 554         {
 555           g_set_error_literal (error,
 556                                G_IO_ERROR,
 557                                G_IO_ERROR_FAILED,
 558                                _("Unexpected type of ancillary data"));
 559           goto out;
 560         }
 561
 562       ret = g_unix_credentials_message_get_credentials (G_UNIX_CREDENTIALS_MESSAGE (scms[0]));
 563       g_object_ref (ret);
 564     }
 565   else
 566     {
 567       if (nscm != 0)
 568         {
 569           g_set_error (error,
 570                        G_IO_ERROR,
 571                        G_IO_ERROR_FAILED,
 572                        _("Not expecting control message, but got %d"),
 573                        nscm);
 574           goto out;
 575         }
 576       else
 577         {
 578           ret = g_socket_get_credentials (socket, error);
 579         }
 580     }
 581
 582  out:
 583
 584 #ifdef __linux__
 585   if (turn_off_so_passcreds)
 586     {
 587       if (!g_socket_set_option (socket,
 588                                 SOL_SOCKET,
 589                                 SO_PASSCRED,
 590                                 FALSE,
 591                                 NULL))
 592         {
 593           g_set_error (error,
 594                        G_IO_ERROR,
 595                        g_io_error_from_errno (errno),
 596                        _("Error while disabling SO_PASSCRED: %s"),
 597                        strerror (errno));
 598           goto out;
 599         }
 600     }
 601 #endif
 602
 603   if (scms != NULL)
 604     {
 605       for (n = 0; n < nscm; n++)
 606         g_object_unref (scms[n]);
 607       g_free (scms);
 608     }
 609   g_object_unref (socket);
 610   return ret;
 611 }
 612
 613 static void
 614 receive_credentials_async_thread (GTask         *task,
 615                                   gpointer       source_object,
 616                                   gpointer       task_data,
 617                                   GCancellable  *cancellable)
 618 {
 619   GCredentials *creds;
 620   GError *error = NULL;
 621
 622   creds = g_unix_connection_receive_credentials (G_UNIX_CONNECTION (source_object),
 623                                                  cancellable,
 624                                                  &error);
 625   if (creds)
 626     g_task_return_pointer (task, creds, g_object_unref);
 627   else
 628     g_task_return_error (task, error);
 629   g_object_unref (task);
 630 }
 631
 632 /**
 633  * g_unix_connection_receive_credentials_async:
 634  * @connection: A #GUnixConnection.
 635  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
 636  * @callback: (scope async): a #GAsyncReadyCallback to call when the request is satisfied
 637  * @user_data: (closure): the data to pass to callback function
 638  *
 639  * Asynchronously receive credentials.
 640  *
 641  * For more details, see g_unix_connection_receive_credentials() which is
 642  * the synchronous version of this call.
 643  *
 644  * When the operation is finished, @callback will be called. You can then call
 645  * g_unix_connection_receive_credentials_finish() to get the result of the operation.
 646  *
 647  * Since: 2.32
 648  **/
 649 void
 650 g_unix_connection_receive_credentials_async (GUnixConnection      *connection,
 651                                               GCancellable         *cancellable,
 652                                               GAsyncReadyCallback   callback,
 653                                               gpointer              user_data)
 654 {
 655   GTask *task;
 656
 657   task = g_task_new (connection, cancellable, callback, user_data);
 658
 659   g_task_run_in_thread (task, receive_credentials_async_thread);
 660 }
 661
 662 /**
 663  * g_unix_connection_receive_credentials_finish:
 664  * @connection: A #GUnixConnection.
 665  * @result: a #GAsyncResult.
 666  * @error: a #GError, or %NULL
 667  *
 668  * Finishes an asynchronous receive credentials operation started with
 669  * g_unix_connection_receive_credentials_async().
 670  *
 671  * Returns: (transfer full): a #GCredentials, or %NULL on error.
 672  *     Free the returned object with g_object_unref().
 673  *
 674  * Since: 2.32
 675  **/
 676 GCredentials *
 677 g_unix_connection_receive_credentials_finish (GUnixConnection *connection,
 678                                               GAsyncResult    *result,
 679                                               GError         **error)
 680 {
 681   g_return_val_if_fail (g_task_is_valid (result, connection), NULL);
 682
 683   return g_task_propagate_pointer (G_TASK (result), error);
 684 }