gio/gunixinputstream.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2006-2007 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  *
  20  * Author: Alexander Larsson <alexl@redhat.com>
  21  */
  22
  23 #include "config.h"
  24
  25 #include <sys/types.h>
  26 #include <sys/stat.h>
  27 #include <unistd.h>
  28 #include <errno.h>
  29 #include <stdio.h>
  30 #include <fcntl.h>
  31
  32 #include <glib.h>
  33 #include <glib/gstdio.h>
  34 #include "gioerror.h"
  35 #include "gsimpleasyncresult.h"
  36 #include "gunixinputstream.h"
  37 #include "gcancellable.h"
  38 #include "gasynchelper.h"
  39 #include "gfiledescriptorbased.h"
  40 #include "glibintl.h"
  41
  42
  43 /**
  44  * SECTION:gunixinputstream
  45  * @short_description: Streaming input operations for UNIX file descriptors
  46  * @include: gio/gunixinputstream.h
  47  * @see_also: #GInputStream
  48  *
  49  * #GUnixInputStream implements #GInputStream for reading from a UNIX
  50  * file descriptor, including asynchronous operations. (If the file
  51  * descriptor refers to a socket or pipe, this will use poll() to do
  52  * asynchronous I/O. If it refers to a regular file, it will fall back
  53  * to doing asynchronous I/O in another thread.)
  54  *
  55  * Note that <filename>&lt;gio/gunixinputstream.h&gt;</filename> belongs
  56  * to the UNIX-specific GIO interfaces, thus you have to use the
  57  * <filename>gio-unix-2.0.pc</filename> pkg-config file when using it.
  58  */
  59
  60 enum {
  61   PROP_0,
  62   PROP_FD,
  63   PROP_CLOSE_FD
  64 };
  65
  66 static void g_unix_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface);
  67 static void g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);
  68
  69 G_DEFINE_TYPE_WITH_CODE (GUnixInputStream, g_unix_input_stream, G_TYPE_INPUT_STREAM,
  70                          G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_INPUT_STREAM,
  71                                                 g_unix_input_stream_pollable_iface_init)
  72                          G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
  73                                                 g_unix_input_stream_file_descriptor_based_iface_init)
  74                          )
  75
  76 struct _GUnixInputStreamPrivate {
  77   int fd;
  78   guint close_fd : 1;
  79   guint is_pipe_or_socket : 1;
  80 };
  81
  82 static void     g_unix_input_stream_set_property (GObject              *object,
  83                                                   guint                 prop_id,
  84                                                   const GValue         *value,
  85                                                   GParamSpec           *pspec);
  86 static void     g_unix_input_stream_get_property (GObject              *object,
  87                                                   guint                 prop_id,
  88                                                   GValue               *value,
  89                                                   GParamSpec           *pspec);
  90 static gssize   g_unix_input_stream_read         (GInputStream         *stream,
  91                                                   void                 *buffer,
  92                                                   gsize                 count,
  93                                                   GCancellable         *cancellable,
  94                                                   GError              **error);
  95 static gboolean g_unix_input_stream_close        (GInputStream         *stream,
  96                                                   GCancellable         *cancellable,
  97                                                   GError              **error);
  98 static void     g_unix_input_stream_read_async   (GInputStream         *stream,
  99                                                   void                 *buffer,
 100                                                   gsize                 count,
 101                                                   int                   io_priority,
 102                                                   GCancellable         *cancellable,
 103                                                   GAsyncReadyCallback   callback,
 104                                                   gpointer              data);
 105 static gssize   g_unix_input_stream_read_finish  (GInputStream         *stream,
 106                                                   GAsyncResult         *result,
 107                                                   GError              **error);
 108 static void     g_unix_input_stream_skip_async   (GInputStream         *stream,
 109                                                   gsize                 count,
 110                                                   int                   io_priority,
 111                                                   GCancellable         *cancellable,
 112                                                   GAsyncReadyCallback   callback,
 113                                                   gpointer              data);
 114 static gssize   g_unix_input_stream_skip_finish  (GInputStream         *stream,
 115                                                   GAsyncResult         *result,
 116                                                   GError              **error);
 117 static void     g_unix_input_stream_close_async  (GInputStream         *stream,
 118                                                   int                   io_priority,
 119                                                   GCancellable         *cancellable,
 120                                                   GAsyncReadyCallback   callback,
 121                                                   gpointer              data);
 122 static gboolean g_unix_input_stream_close_finish (GInputStream         *stream,
 123                                                   GAsyncResult         *result,
 124                                                   GError              **error);
 125
 126 static gboolean g_unix_input_stream_pollable_is_readable   (GPollableInputStream *stream);
 127 static GSource *g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,
 128                                                             GCancellable         *cancellable);
 129
 130 static void
 131 g_unix_input_stream_finalize (GObject *object)
 132 {
 133   G_OBJECT_CLASS (g_unix_input_stream_parent_class)->finalize (object);
 134 }
 135
 136 static void
 137 g_unix_input_stream_class_init (GUnixInputStreamClass *klass)
 138 {
 139   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 140   GInputStreamClass *stream_class = G_INPUT_STREAM_CLASS (klass);
 141
 142   g_type_class_add_private (klass, sizeof (GUnixInputStreamPrivate));
 143
 144   gobject_class->get_property = g_unix_input_stream_get_property;
 145   gobject_class->set_property = g_unix_input_stream_set_property;
 146   gobject_class->finalize = g_unix_input_stream_finalize;
 147
 148   stream_class->read_fn = g_unix_input_stream_read;
 149   stream_class->close_fn = g_unix_input_stream_close;
 150   stream_class->read_async = g_unix_input_stream_read_async;
 151   stream_class->read_finish = g_unix_input_stream_read_finish;
 152   if (0)
 153     {
 154       /* TODO: Implement instead of using fallbacks */
 155       stream_class->skip_async = g_unix_input_stream_skip_async;
 156       stream_class->skip_finish = g_unix_input_stream_skip_finish;
 157     }
 158   stream_class->close_async = g_unix_input_stream_close_async;
 159   stream_class->close_finish = g_unix_input_stream_close_finish;
 160
 161   /**
 162    * GUnixInputStream:fd:
 163    *
 164    * The file descriptor that the stream reads from.
 165    *
 166    * Since: 2.20
 167    */
 168   g_object_class_install_property (gobject_class,
 169                                    PROP_FD,
 170                                    g_param_spec_int ("fd",
 171                                                      P_("File descriptor"),
 172                                                      P_("The file descriptor to read from"),
 173                                                      G_MININT, G_MAXINT, -1,
 174                                                      G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 175
 176   /**
 177    * GUnixInputStream:close-fd:
 178    *
 179    * Whether to close the file descriptor when the stream is closed.
 180    *
 181    * Since: 2.20
 182    */
 183   g_object_class_install_property (gobject_class,
 184                                    PROP_CLOSE_FD,
 185                                    g_param_spec_boolean ("close-fd",
 186                                                          P_("Close file descriptor"),
 187                                                          P_("Whether to close the file descriptor when the stream is closed"),
 188                                                          TRUE,
 189                                                          G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 190 }
 191
 192 static void
 193 g_unix_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface)
 194 {
 195   iface->is_readable = g_unix_input_stream_pollable_is_readable;
 196   iface->create_source = g_unix_input_stream_pollable_create_source;
 197 }
 198
 199 static void
 200 g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
 201 {
 202   iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_input_stream_get_fd;
 203 }
 204
 205 static void
 206 g_unix_input_stream_set_property (GObject         *object,
 207                                   guint            prop_id,
 208                                   const GValue    *value,
 209                                   GParamSpec      *pspec)
 210 {
 211   GUnixInputStream *unix_stream;
 212
 213   unix_stream = G_UNIX_INPUT_STREAM (object);
 214
 215   switch (prop_id)
 216     {
 217     case PROP_FD:
 218       unix_stream->priv->fd = g_value_get_int (value);
 219       if (lseek (unix_stream->priv->fd, 0, SEEK_CUR) == -1 && errno == ESPIPE)
 220         unix_stream->priv->is_pipe_or_socket = TRUE;
 221       else
 222         unix_stream->priv->is_pipe_or_socket = FALSE;
 223       break;
 224     case PROP_CLOSE_FD:
 225       unix_stream->priv->close_fd = g_value_get_boolean (value);
 226       break;
 227     default:
 228       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 229       break;
 230     }
 231 }
 232
 233 static void
 234 g_unix_input_stream_get_property (GObject    *object,
 235                                   guint       prop_id,
 236                                   GValue     *value,
 237                                   GParamSpec *pspec)
 238 {
 239   GUnixInputStream *unix_stream;
 240
 241   unix_stream = G_UNIX_INPUT_STREAM (object);
 242
 243   switch (prop_id)
 244     {
 245     case PROP_FD:
 246       g_value_set_int (value, unix_stream->priv->fd);
 247       break;
 248     case PROP_CLOSE_FD:
 249       g_value_set_boolean (value, unix_stream->priv->close_fd);
 250       break;
 251     default:
 252       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 253     }
 254 }
 255
 256 static void
 257 g_unix_input_stream_init (GUnixInputStream *unix_stream)
 258 {
 259   unix_stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (unix_stream,
 260                                                    G_TYPE_UNIX_INPUT_STREAM,
 261                                                    GUnixInputStreamPrivate);
 262
 263   unix_stream->priv->fd = -1;
 264   unix_stream->priv->close_fd = TRUE;
 265 }
 266
 267 /**
 268  * g_unix_input_stream_new:
 269  * @fd: a UNIX file descriptor
 270  * @close_fd: %TRUE to close the file descriptor when done
 271  *
 272  * Creates a new #GUnixInputStream for the given @fd.
 273  *
 274  * If @close_fd is %TRUE, the file descriptor will be closed
 275  * when the stream is closed.
 276  *
 277  * Returns: a new #GUnixInputStream
 278  **/
 279 GInputStream *
 280 g_unix_input_stream_new (gint     fd,
 281                          gboolean close_fd)
 282 {
 283   GUnixInputStream *stream;
 284
 285   g_return_val_if_fail (fd != -1, NULL);
 286
 287   stream = g_object_new (G_TYPE_UNIX_INPUT_STREAM,
 288                          "fd", fd,
 289                          "close-fd", close_fd,
 290                          NULL);
 291
 292   return G_INPUT_STREAM (stream);
 293 }
 294
 295 /**
 296  * g_unix_input_stream_set_close_fd:
 297  * @stream: a #GUnixInputStream
 298  * @close_fd: %TRUE to close the file descriptor when done
 299  *
 300  * Sets whether the file descriptor of @stream shall be closed
 301  * when the stream is closed.
 302  *
 303  * Since: 2.20
 304  */
 305 void
 306 g_unix_input_stream_set_close_fd (GUnixInputStream *stream,
 307                                   gboolean          close_fd)
 308 {
 309   g_return_if_fail (G_IS_UNIX_INPUT_STREAM (stream));
 310
 311   close_fd = close_fd != FALSE;
 312   if (stream->priv->close_fd != close_fd)
 313     {
 314       stream->priv->close_fd = close_fd;
 315       g_object_notify (G_OBJECT (stream), "close-fd");
 316     }
 317 }
 318
 319 /**
 320  * g_unix_input_stream_get_close_fd:
 321  * @stream: a #GUnixInputStream
 322  *
 323  * Returns whether the file descriptor of @stream will be
 324  * closed when the stream is closed.
 325  *
 326  * Return value: %TRUE if the file descriptor is closed when done
 327  *
 328  * Since: 2.20
 329  */
 330 gboolean
 331 g_unix_input_stream_get_close_fd (GUnixInputStream *stream)
 332 {
 333   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), FALSE);
 334
 335   return stream->priv->close_fd;
 336 }
 337
 338 /**
 339  * g_unix_input_stream_get_fd:
 340  * @stream: a #GUnixInputStream
 341  *
 342  * Return the UNIX file descriptor that the stream reads from.
 343  *
 344  * Return value: The file descriptor of @stream
 345  *
 346  * Since: 2.20
 347  */
 348 gint
 349 g_unix_input_stream_get_fd (GUnixInputStream *stream)
 350 {
 351   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), -1);
 352
 353   return stream->priv->fd;
 354 }
 355
 356 static gssize
 357 g_unix_input_stream_read (GInputStream  *stream,
 358                           void          *buffer,
 359                           gsize          count,
 360                           GCancellable  *cancellable,
 361                           GError       **error)
 362 {
 363   GUnixInputStream *unix_stream;
 364   gssize res;
 365   GPollFD poll_fds[2];
 366   int poll_ret;
 367
 368   unix_stream = G_UNIX_INPUT_STREAM (stream);
 369
 370   if (unix_stream->priv->is_pipe_or_socket &&
 371       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
 372     {
 373       poll_fds[0].fd = unix_stream->priv->fd;
 374       poll_fds[0].events = G_IO_IN;
 375       do
 376         poll_ret = g_poll (poll_fds, 2, -1);
 377       while (poll_ret == -1 && errno == EINTR);
 378       g_cancellable_release_fd (cancellable);
 379
 380       if (poll_ret == -1)
 381         {
 382           int errsv = errno;
 383
 384           g_set_error (error, G_IO_ERROR,
 385                        g_io_error_from_errno (errsv),
 386                        _("Error reading from unix: %s"),
 387                        g_strerror (errsv));
 388           return -1;
 389         }
 390     }
 391
 392   while (1)
 393     {
 394       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 395         return -1;
 396       res = read (unix_stream->priv->fd, buffer, count);
 397       if (res == -1)
 398         {
 399           int errsv = errno;
 400
 401           if (errsv == EINTR)
 402             continue;
 403
 404           g_set_error (error, G_IO_ERROR,
 405                        g_io_error_from_errno (errsv),
 406                        _("Error reading from unix: %s"),
 407                        g_strerror (errsv));
 408         }
 409
 410       break;
 411     }
 412
 413   return res;
 414 }
 415
 416 static gboolean
 417 g_unix_input_stream_close (GInputStream  *stream,
 418                            GCancellable  *cancellable,
 419                            GError       **error)
 420 {
 421   GUnixInputStream *unix_stream;
 422   int res;
 423
 424   unix_stream = G_UNIX_INPUT_STREAM (stream);
 425
 426   if (!unix_stream->priv->close_fd)
 427     return TRUE;
 428
 429   while (1)
 430     {
 431       /* This might block during the close. Doesn't seem to be a way to avoid it though. */
 432       res = close (unix_stream->priv->fd);
 433       if (res == -1)
 434         {
 435           int errsv = errno;
 436
 437           g_set_error (error, G_IO_ERROR,
 438                        g_io_error_from_errno (errsv),
 439                        _("Error closing unix: %s"),
 440                        g_strerror (errsv));
 441         }
 442       break;
 443     }
 444
 445   return res != -1;
 446 }
 447
 448 typedef struct {
 449   gsize count;
 450   void *buffer;
 451   GAsyncReadyCallback callback;
 452   gpointer user_data;
 453   GCancellable *cancellable;
 454   GUnixInputStream *stream;
 455 } ReadAsyncData;
 456
 457 static gboolean
 458 read_async_cb (int            fd,
 459                GIOCondition   condition,
 460                ReadAsyncData *data)
 461 {
 462   GSimpleAsyncResult *simple;
 463   GError *error = NULL;
 464   gssize count_read;
 465
 466   /* We know that we can read from fd once without blocking */
 467   while (1)
 468     {
 469       if (g_cancellable_set_error_if_cancelled (data->cancellable, &error))
 470         {
 471           count_read = -1;
 472           break;
 473         }
 474       count_read = read (data->stream->priv->fd, data->buffer, data->count);
 475       if (count_read == -1)
 476         {
 477           int errsv = errno;
 478
 479           if (errsv == EINTR)
 480             continue;
 481
 482           g_set_error (&error, G_IO_ERROR,
 483                        g_io_error_from_errno (errsv),
 484                        _("Error reading from unix: %s"),
 485                        g_strerror (errsv));
 486         }
 487       break;
 488     }
 489
 490   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 491                                       data->callback,
 492                                       data->user_data,
 493                                       g_unix_input_stream_read_async);
 494
 495   g_simple_async_result_set_op_res_gssize (simple, count_read);
 496
 497   if (count_read == -1)
 498     g_simple_async_result_take_error (simple, error);
 499
 500   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 501   g_simple_async_result_complete (simple);
 502   g_object_unref (simple);
 503
 504   return FALSE;
 505 }
 506
 507 static void
 508 g_unix_input_stream_read_async (GInputStream        *stream,
 509                                 void                *buffer,
 510                                 gsize                count,
 511                                 int                  io_priority,
 512                                 GCancellable        *cancellable,
 513                                 GAsyncReadyCallback  callback,
 514                                 gpointer             user_data)
 515 {
 516   GSource *source;
 517   GUnixInputStream *unix_stream;
 518   ReadAsyncData *data;
 519
 520   unix_stream = G_UNIX_INPUT_STREAM (stream);
 521
 522   if (!unix_stream->priv->is_pipe_or_socket)
 523     {
 524       G_INPUT_STREAM_CLASS (g_unix_input_stream_parent_class)->
 525         read_async (stream, buffer, count, io_priority,
 526                     cancellable, callback, user_data);
 527       return;
 528     }
 529
 530   data = g_new0 (ReadAsyncData, 1);
 531   data->count = count;
 532   data->buffer = buffer;
 533   data->callback = callback;
 534   data->user_data = user_data;
 535   data->cancellable = cancellable;
 536   data->stream = unix_stream;
 537
 538   source = _g_fd_source_new (unix_stream->priv->fd,
 539                              G_IO_IN,
 540                              cancellable);
 541   g_source_set_name (source, "GUnixInputStream");
 542
 543   g_source_set_callback (source, (GSourceFunc)read_async_cb, data, g_free);
 544   g_source_attach (source, g_main_context_get_thread_default ());
 545
 546   g_source_unref (source);
 547 }
 548
 549 static gssize
 550 g_unix_input_stream_read_finish (GInputStream  *stream,
 551                                  GAsyncResult  *result,
 552                                  GError       **error)
 553 {
 554   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 555   GSimpleAsyncResult *simple;
 556   gssize nread;
 557
 558   if (!unix_stream->priv->is_pipe_or_socket)
 559     {
 560       return G_INPUT_STREAM_CLASS (g_unix_input_stream_parent_class)->
 561         read_finish (stream, result, error);
 562     }
 563
 564   simple = G_SIMPLE_ASYNC_RESULT (result);
 565   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_unix_input_stream_read_async);
 566
 567   nread = g_simple_async_result_get_op_res_gssize (simple);
 568   return nread;
 569 }
 570
 571 static void
 572 g_unix_input_stream_skip_async (GInputStream        *stream,
 573                                 gsize                count,
 574                                 int                  io_priority,
 575                                 GCancellable        *cancellable,
 576                                 GAsyncReadyCallback  callback,
 577                                 gpointer             data)
 578 {
 579   g_warn_if_reached ();
 580   /* TODO: Not implemented */
 581 }
 582
 583 static gssize
 584 g_unix_input_stream_skip_finish  (GInputStream  *stream,
 585                                   GAsyncResult  *result,
 586                                   GError       **error)
 587 {
 588   g_warn_if_reached ();
 589   return 0;
 590   /* TODO: Not implemented */
 591 }
 592
 593
 594 typedef struct {
 595   GInputStream *stream;
 596   GAsyncReadyCallback callback;
 597   gpointer user_data;
 598 } CloseAsyncData;
 599
 600 static void
 601 close_async_data_free (gpointer _data)
 602 {
 603   CloseAsyncData *data = _data;
 604
 605   g_free (data);
 606 }
 607
 608 static gboolean
 609 close_async_cb (CloseAsyncData *data)
 610 {
 611   GUnixInputStream *unix_stream;
 612   GSimpleAsyncResult *simple;
 613   GError *error = NULL;
 614   gboolean result;
 615   int res;
 616
 617   unix_stream = G_UNIX_INPUT_STREAM (data->stream);
 618
 619   if (!unix_stream->priv->close_fd)
 620     {
 621       result = TRUE;
 622       goto out;
 623     }
 624
 625   while (1)
 626     {
 627       res = close (unix_stream->priv->fd);
 628       if (res == -1)
 629         {
 630           int errsv = errno;
 631
 632           g_set_error (&error, G_IO_ERROR,
 633                        g_io_error_from_errno (errsv),
 634                        _("Error closing unix: %s"),
 635                        g_strerror (errsv));
 636         }
 637       break;
 638     }
 639
 640   result = res != -1;
 641
 642  out:
 643   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 644                                       data->callback,
 645                                       data->user_data,
 646                                       g_unix_input_stream_close_async);
 647
 648   if (!result)
 649     g_simple_async_result_take_error (simple, error);
 650
 651   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 652   g_simple_async_result_complete (simple);
 653   g_object_unref (simple);
 654
 655   return FALSE;
 656 }
 657
 658 static void
 659 g_unix_input_stream_close_async (GInputStream        *stream,
 660                                  int                  io_priority,
 661                                  GCancellable        *cancellable,
 662                                  GAsyncReadyCallback  callback,
 663                                  gpointer             user_data)
 664 {
 665   GSource *idle;
 666   CloseAsyncData *data;
 667
 668   data = g_new0 (CloseAsyncData, 1);
 669
 670   data->stream = stream;
 671   data->callback = callback;
 672   data->user_data = user_data;
 673
 674   idle = g_idle_source_new ();
 675   g_source_set_callback (idle, (GSourceFunc)close_async_cb, data, close_async_data_free);
 676   g_source_attach (idle, g_main_context_get_thread_default ());
 677   g_source_unref (idle);
 678 }
 679
 680 static gboolean
 681 g_unix_input_stream_close_finish (GInputStream  *stream,
 682                                   GAsyncResult  *result,
 683                                   GError       **error)
 684 {
 685   /* Failures handled in generic close_finish code */
 686   return TRUE;
 687 }
 688
 689 static gboolean
 690 g_unix_input_stream_pollable_is_readable (GPollableInputStream *stream)
 691 {
 692   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 693   GPollFD poll_fd;
 694   gint result;
 695
 696   poll_fd.fd = unix_stream->priv->fd;
 697   poll_fd.events = G_IO_IN;
 698
 699   do
 700     result = g_poll (&poll_fd, 1, 0);
 701   while (result == -1 && errno == EINTR);
 702
 703   return poll_fd.revents != 0;
 704 }
 705
 706 static GSource *
 707 g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,
 708                                             GCancellable         *cancellable)
 709 {
 710   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 711   GSource *inner_source, *pollable_source;
 712
 713   pollable_source = g_pollable_source_new (G_OBJECT (stream));
 714
 715   inner_source = _g_fd_source_new (unix_stream->priv->fd, G_IO_IN, cancellable);
 716   g_source_set_dummy_callback (inner_source);
 717   g_source_add_child_source (pollable_source, inner_source);
 718   g_source_unref (inner_source);
 719
 720   return pollable_source;
 721 }