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 like
  54  * #GLocalFileInputStream.)
  55  *
  56  * Note that <filename>&lt;gio/gunixinputstream.h&gt;</filename> belongs
  57  * to the UNIX-specific GIO interfaces, thus you have to use the
  58  * <filename>gio-unix-2.0.pc</filename> pkg-config file when using it.
  59  */
  60
  61 enum {
  62   PROP_0,
  63   PROP_FD,
  64   PROP_CLOSE_FD
  65 };
  66
  67 static void g_unix_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface);
  68 static void g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);
  69
  70 G_DEFINE_TYPE_WITH_CODE (GUnixInputStream, g_unix_input_stream, G_TYPE_INPUT_STREAM,
  71                          G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_INPUT_STREAM,
  72                                                 g_unix_input_stream_pollable_iface_init)
  73                          G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
  74                                                 g_unix_input_stream_file_descriptor_based_iface_init)
  75                          )
  76
  77 struct _GUnixInputStreamPrivate {
  78   int fd;
  79   guint close_fd : 1;
  80   guint is_pipe_or_socket : 1;
  81 };
  82
  83 static void     g_unix_input_stream_set_property (GObject              *object,
  84                                                   guint                 prop_id,
  85                                                   const GValue         *value,
  86                                                   GParamSpec           *pspec);
  87 static void     g_unix_input_stream_get_property (GObject              *object,
  88                                                   guint                 prop_id,
  89                                                   GValue               *value,
  90                                                   GParamSpec           *pspec);
  91 static gssize   g_unix_input_stream_read         (GInputStream         *stream,
  92                                                   void                 *buffer,
  93                                                   gsize                 count,
  94                                                   GCancellable         *cancellable,
  95                                                   GError              **error);
  96 static gboolean g_unix_input_stream_close        (GInputStream         *stream,
  97                                                   GCancellable         *cancellable,
  98                                                   GError              **error);
  99 static void     g_unix_input_stream_read_async   (GInputStream         *stream,
 100                                                   void                 *buffer,
 101                                                   gsize                 count,
 102                                                   int                   io_priority,
 103                                                   GCancellable         *cancellable,
 104                                                   GAsyncReadyCallback   callback,
 105                                                   gpointer              data);
 106 static gssize   g_unix_input_stream_read_finish  (GInputStream         *stream,
 107                                                   GAsyncResult         *result,
 108                                                   GError              **error);
 109 static void     g_unix_input_stream_skip_async   (GInputStream         *stream,
 110                                                   gsize                 count,
 111                                                   int                   io_priority,
 112                                                   GCancellable         *cancellable,
 113                                                   GAsyncReadyCallback   callback,
 114                                                   gpointer              data);
 115 static gssize   g_unix_input_stream_skip_finish  (GInputStream         *stream,
 116                                                   GAsyncResult         *result,
 117                                                   GError              **error);
 118 static void     g_unix_input_stream_close_async  (GInputStream         *stream,
 119                                                   int                   io_priority,
 120                                                   GCancellable         *cancellable,
 121                                                   GAsyncReadyCallback   callback,
 122                                                   gpointer              data);
 123 static gboolean g_unix_input_stream_close_finish (GInputStream         *stream,
 124                                                   GAsyncResult         *result,
 125                                                   GError              **error);
 126
 127 static gboolean g_unix_input_stream_pollable_is_readable   (GPollableInputStream *stream);
 128 static GSource *g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,
 129                                                             GCancellable         *cancellable);
 130
 131 static void
 132 g_unix_input_stream_finalize (GObject *object)
 133 {
 134   G_OBJECT_CLASS (g_unix_input_stream_parent_class)->finalize (object);
 135 }
 136
 137 static void
 138 g_unix_input_stream_class_init (GUnixInputStreamClass *klass)
 139 {
 140   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 141   GInputStreamClass *stream_class = G_INPUT_STREAM_CLASS (klass);
 142
 143   g_type_class_add_private (klass, sizeof (GUnixInputStreamPrivate));
 144
 145   gobject_class->get_property = g_unix_input_stream_get_property;
 146   gobject_class->set_property = g_unix_input_stream_set_property;
 147   gobject_class->finalize = g_unix_input_stream_finalize;
 148
 149   stream_class->read_fn = g_unix_input_stream_read;
 150   stream_class->close_fn = g_unix_input_stream_close;
 151   stream_class->read_async = g_unix_input_stream_read_async;
 152   stream_class->read_finish = g_unix_input_stream_read_finish;
 153   if (0)
 154     {
 155       /* TODO: Implement instead of using fallbacks */
 156       stream_class->skip_async = g_unix_input_stream_skip_async;
 157       stream_class->skip_finish = g_unix_input_stream_skip_finish;
 158     }
 159   stream_class->close_async = g_unix_input_stream_close_async;
 160   stream_class->close_finish = g_unix_input_stream_close_finish;
 161
 162   /**
 163    * GUnixInputStream:fd:
 164    *
 165    * The file descriptor that the stream reads from.
 166    *
 167    * Since: 2.20
 168    */
 169   g_object_class_install_property (gobject_class,
 170                                    PROP_FD,
 171                                    g_param_spec_int ("fd",
 172                                                      P_("File descriptor"),
 173                                                      P_("The file descriptor to read from"),
 174                                                      G_MININT, G_MAXINT, -1,
 175                                                      G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 176
 177   /**
 178    * GUnixInputStream:close-fd:
 179    *
 180    * Whether to close the file descriptor when the stream is closed.
 181    *
 182    * Since: 2.20
 183    */
 184   g_object_class_install_property (gobject_class,
 185                                    PROP_CLOSE_FD,
 186                                    g_param_spec_boolean ("close-fd",
 187                                                          P_("Close file descriptor"),
 188                                                          P_("Whether to close the file descriptor when the stream is closed"),
 189                                                          TRUE,
 190                                                          G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 191 }
 192
 193 static void
 194 g_unix_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface)
 195 {
 196   iface->is_readable = g_unix_input_stream_pollable_is_readable;
 197   iface->create_source = g_unix_input_stream_pollable_create_source;
 198 }
 199
 200 static void
 201 g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
 202 {
 203   iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_input_stream_get_fd;
 204 }
 205
 206 static void
 207 g_unix_input_stream_set_property (GObject         *object,
 208                                   guint            prop_id,
 209                                   const GValue    *value,
 210                                   GParamSpec      *pspec)
 211 {
 212   GUnixInputStream *unix_stream;
 213
 214   unix_stream = G_UNIX_INPUT_STREAM (object);
 215
 216   switch (prop_id)
 217     {
 218     case PROP_FD:
 219       unix_stream->priv->fd = g_value_get_int (value);
 220       if (lseek (unix_stream->priv->fd, 0, SEEK_CUR) == -1 && errno == ESPIPE)
 221         unix_stream->priv->is_pipe_or_socket = TRUE;
 222       else
 223         unix_stream->priv->is_pipe_or_socket = FALSE;
 224       break;
 225     case PROP_CLOSE_FD:
 226       unix_stream->priv->close_fd = g_value_get_boolean (value);
 227       break;
 228     default:
 229       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 230       break;
 231     }
 232 }
 233
 234 static void
 235 g_unix_input_stream_get_property (GObject    *object,
 236                                   guint       prop_id,
 237                                   GValue     *value,
 238                                   GParamSpec *pspec)
 239 {
 240   GUnixInputStream *unix_stream;
 241
 242   unix_stream = G_UNIX_INPUT_STREAM (object);
 243
 244   switch (prop_id)
 245     {
 246     case PROP_FD:
 247       g_value_set_int (value, unix_stream->priv->fd);
 248       break;
 249     case PROP_CLOSE_FD:
 250       g_value_set_boolean (value, unix_stream->priv->close_fd);
 251       break;
 252     default:
 253       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 254     }
 255 }
 256
 257 static void
 258 g_unix_input_stream_init (GUnixInputStream *unix_stream)
 259 {
 260   unix_stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (unix_stream,
 261                                                    G_TYPE_UNIX_INPUT_STREAM,
 262                                                    GUnixInputStreamPrivate);
 263
 264   unix_stream->priv->fd = -1;
 265   unix_stream->priv->close_fd = TRUE;
 266 }
 267
 268 /**
 269  * g_unix_input_stream_new:
 270  * @fd: a UNIX file descriptor
 271  * @close_fd: %TRUE to close the file descriptor when done
 272  *
 273  * Creates a new #GUnixInputStream for the given @fd.
 274  *
 275  * If @close_fd is %TRUE, the file descriptor will be closed
 276  * when the stream is closed.
 277  *
 278  * Returns: a new #GUnixInputStream
 279  **/
 280 GInputStream *
 281 g_unix_input_stream_new (gint     fd,
 282                          gboolean close_fd)
 283 {
 284   GUnixInputStream *stream;
 285
 286   g_return_val_if_fail (fd != -1, NULL);
 287
 288   stream = g_object_new (G_TYPE_UNIX_INPUT_STREAM,
 289                          "fd", fd,
 290                          "close-fd", close_fd,
 291                          NULL);
 292
 293   return G_INPUT_STREAM (stream);
 294 }
 295
 296 /**
 297  * g_unix_input_stream_set_close_fd:
 298  * @stream: a #GUnixInputStream
 299  * @close_fd: %TRUE to close the file descriptor when done
 300  *
 301  * Sets whether the file descriptor of @stream shall be closed
 302  * when the stream is closed.
 303  *
 304  * Since: 2.20
 305  */
 306 void
 307 g_unix_input_stream_set_close_fd (GUnixInputStream *stream,
 308                                   gboolean          close_fd)
 309 {
 310   g_return_if_fail (G_IS_UNIX_INPUT_STREAM (stream));
 311
 312   close_fd = close_fd != FALSE;
 313   if (stream->priv->close_fd != close_fd)
 314     {
 315       stream->priv->close_fd = close_fd;
 316       g_object_notify (G_OBJECT (stream), "close-fd");
 317     }
 318 }
 319
 320 /**
 321  * g_unix_input_stream_get_close_fd:
 322  * @stream: a #GUnixInputStream
 323  *
 324  * Returns whether the file descriptor of @stream will be
 325  * closed when the stream is closed.
 326  *
 327  * Return value: %TRUE if the file descriptor is closed when done
 328  *
 329  * Since: 2.20
 330  */
 331 gboolean
 332 g_unix_input_stream_get_close_fd (GUnixInputStream *stream)
 333 {
 334   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), FALSE);
 335
 336   return stream->priv->close_fd;
 337 }
 338
 339 /**
 340  * g_unix_input_stream_get_fd:
 341  * @stream: a #GUnixInputStream
 342  *
 343  * Return the UNIX file descriptor that the stream reads from.
 344  *
 345  * Return value: The file descriptor of @stream
 346  *
 347  * Since: 2.20
 348  */
 349 gint
 350 g_unix_input_stream_get_fd (GUnixInputStream *stream)
 351 {
 352   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), -1);
 353
 354   return stream->priv->fd;
 355 }
 356
 357 static gssize
 358 g_unix_input_stream_read (GInputStream  *stream,
 359                           void          *buffer,
 360                           gsize          count,
 361                           GCancellable  *cancellable,
 362                           GError       **error)
 363 {
 364   GUnixInputStream *unix_stream;
 365   gssize res;
 366   GPollFD poll_fds[2];
 367   int poll_ret;
 368
 369   unix_stream = G_UNIX_INPUT_STREAM (stream);
 370
 371   if (unix_stream->priv->is_pipe_or_socket &&
 372       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
 373     {
 374       poll_fds[0].fd = unix_stream->priv->fd;
 375       poll_fds[0].events = G_IO_IN;
 376       do
 377         poll_ret = g_poll (poll_fds, 2, -1);
 378       while (poll_ret == -1 && errno == EINTR);
 379       g_cancellable_release_fd (cancellable);
 380
 381       if (poll_ret == -1)
 382         {
 383           int errsv = errno;
 384
 385           g_set_error (error, G_IO_ERROR,
 386                        g_io_error_from_errno (errsv),
 387                        _("Error reading from unix: %s"),
 388                        g_strerror (errsv));
 389           return -1;
 390         }
 391     }
 392
 393   while (1)
 394     {
 395       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 396         return -1;
 397       res = read (unix_stream->priv->fd, buffer, count);
 398       if (res == -1)
 399         {
 400           int errsv = errno;
 401
 402           if (errsv == EINTR)
 403             continue;
 404
 405           g_set_error (error, G_IO_ERROR,
 406                        g_io_error_from_errno (errsv),
 407                        _("Error reading from unix: %s"),
 408                        g_strerror (errsv));
 409         }
 410
 411       break;
 412     }
 413
 414   return res;
 415 }
 416
 417 static gboolean
 418 g_unix_input_stream_close (GInputStream  *stream,
 419                            GCancellable  *cancellable,
 420                            GError       **error)
 421 {
 422   GUnixInputStream *unix_stream;
 423   int res;
 424
 425   unix_stream = G_UNIX_INPUT_STREAM (stream);
 426
 427   if (!unix_stream->priv->close_fd)
 428     return TRUE;
 429
 430   while (1)
 431     {
 432       /* This might block during the close. Doesn't seem to be a way to avoid it though. */
 433       res = close (unix_stream->priv->fd);
 434       if (res == -1)
 435         {
 436           int errsv = errno;
 437
 438           g_set_error (error, G_IO_ERROR,
 439                        g_io_error_from_errno (errsv),
 440                        _("Error closing unix: %s"),
 441                        g_strerror (errsv));
 442         }
 443       break;
 444     }
 445
 446   return res != -1;
 447 }
 448
 449 typedef struct {
 450   gsize count;
 451   void *buffer;
 452   GAsyncReadyCallback callback;
 453   gpointer user_data;
 454   GCancellable *cancellable;
 455   GUnixInputStream *stream;
 456 } ReadAsyncData;
 457
 458 static gboolean
 459 read_async_cb (int            fd,
 460                GIOCondition   condition,
 461                ReadAsyncData *data)
 462 {
 463   GSimpleAsyncResult *simple;
 464   GError *error = NULL;
 465   gssize count_read;
 466
 467   /* We know that we can read from fd once without blocking */
 468   while (1)
 469     {
 470       if (g_cancellable_set_error_if_cancelled (data->cancellable, &error))
 471         {
 472           count_read = -1;
 473           break;
 474         }
 475       count_read = read (data->stream->priv->fd, data->buffer, data->count);
 476       if (count_read == -1)
 477         {
 478           int errsv = errno;
 479
 480           if (errsv == EINTR)
 481             continue;
 482
 483           g_set_error (&error, G_IO_ERROR,
 484                        g_io_error_from_errno (errsv),
 485                        _("Error reading from unix: %s"),
 486                        g_strerror (errsv));
 487         }
 488       break;
 489     }
 490
 491   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 492                                       data->callback,
 493                                       data->user_data,
 494                                       g_unix_input_stream_read_async);
 495
 496   g_simple_async_result_set_op_res_gssize (simple, count_read);
 497
 498   if (count_read == -1)
 499     g_simple_async_result_take_error (simple, error);
 500
 501   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 502   g_simple_async_result_complete (simple);
 503   g_object_unref (simple);
 504
 505   return FALSE;
 506 }
 507
 508 static void
 509 g_unix_input_stream_read_async (GInputStream        *stream,
 510                                 void                *buffer,
 511                                 gsize                count,
 512                                 int                  io_priority,
 513                                 GCancellable        *cancellable,
 514                                 GAsyncReadyCallback  callback,
 515                                 gpointer             user_data)
 516 {
 517   GSource *source;
 518   GUnixInputStream *unix_stream;
 519   ReadAsyncData *data;
 520
 521   unix_stream = G_UNIX_INPUT_STREAM (stream);
 522
 523   if (!unix_stream->priv->is_pipe_or_socket)
 524     {
 525       G_INPUT_STREAM_CLASS (g_unix_input_stream_parent_class)->
 526         read_async (stream, buffer, count, io_priority,
 527                     cancellable, callback, user_data);
 528       return;
 529     }
 530
 531   data = g_new0 (ReadAsyncData, 1);
 532   data->count = count;
 533   data->buffer = buffer;
 534   data->callback = callback;
 535   data->user_data = user_data;
 536   data->cancellable = cancellable;
 537   data->stream = unix_stream;
 538
 539   source = _g_fd_source_new (unix_stream->priv->fd,
 540                              G_IO_IN,
 541                              cancellable);
 542   g_source_set_name (source, "GUnixInputStream");
 543
 544   g_source_set_callback (source, (GSourceFunc)read_async_cb, data, g_free);
 545   g_source_attach (source, g_main_context_get_thread_default ());
 546
 547   g_source_unref (source);
 548 }
 549
 550 static gssize
 551 g_unix_input_stream_read_finish (GInputStream  *stream,
 552                                  GAsyncResult  *result,
 553                                  GError       **error)
 554 {
 555   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 556   GSimpleAsyncResult *simple;
 557   gssize nread;
 558
 559   if (!unix_stream->priv->is_pipe_or_socket)
 560     {
 561       return G_INPUT_STREAM_CLASS (g_unix_input_stream_parent_class)->
 562         read_finish (stream, result, error);
 563     }
 564
 565   simple = G_SIMPLE_ASYNC_RESULT (result);
 566   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_unix_input_stream_read_async);
 567
 568   nread = g_simple_async_result_get_op_res_gssize (simple);
 569   return nread;
 570 }
 571
 572 static void
 573 g_unix_input_stream_skip_async (GInputStream        *stream,
 574                                 gsize                count,
 575                                 int                  io_priority,
 576                                 GCancellable        *cancellable,
 577                                 GAsyncReadyCallback  callback,
 578                                 gpointer             data)
 579 {
 580   g_warn_if_reached ();
 581   /* TODO: Not implemented */
 582 }
 583
 584 static gssize
 585 g_unix_input_stream_skip_finish  (GInputStream  *stream,
 586                                   GAsyncResult  *result,
 587                                   GError       **error)
 588 {
 589   g_warn_if_reached ();
 590   return 0;
 591   /* TODO: Not implemented */
 592 }
 593
 594
 595 typedef struct {
 596   GInputStream *stream;
 597   GAsyncReadyCallback callback;
 598   gpointer user_data;
 599 } CloseAsyncData;
 600
 601 static void
 602 close_async_data_free (gpointer _data)
 603 {
 604   CloseAsyncData *data = _data;
 605
 606   g_free (data);
 607 }
 608
 609 static gboolean
 610 close_async_cb (CloseAsyncData *data)
 611 {
 612   GUnixInputStream *unix_stream;
 613   GSimpleAsyncResult *simple;
 614   GError *error = NULL;
 615   gboolean result;
 616   int res;
 617
 618   unix_stream = G_UNIX_INPUT_STREAM (data->stream);
 619
 620   if (!unix_stream->priv->close_fd)
 621     {
 622       result = TRUE;
 623       goto out;
 624     }
 625
 626   while (1)
 627     {
 628       res = close (unix_stream->priv->fd);
 629       if (res == -1)
 630         {
 631           int errsv = errno;
 632
 633           g_set_error (&error, G_IO_ERROR,
 634                        g_io_error_from_errno (errsv),
 635                        _("Error closing unix: %s"),
 636                        g_strerror (errsv));
 637         }
 638       break;
 639     }
 640
 641   result = res != -1;
 642
 643  out:
 644   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 645                                       data->callback,
 646                                       data->user_data,
 647                                       g_unix_input_stream_close_async);
 648
 649   if (!result)
 650     g_simple_async_result_take_error (simple, error);
 651
 652   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 653   g_simple_async_result_complete (simple);
 654   g_object_unref (simple);
 655
 656   return FALSE;
 657 }
 658
 659 static void
 660 g_unix_input_stream_close_async (GInputStream        *stream,
 661                                  int                  io_priority,
 662                                  GCancellable        *cancellable,
 663                                  GAsyncReadyCallback  callback,
 664                                  gpointer             user_data)
 665 {
 666   GSource *idle;
 667   CloseAsyncData *data;
 668
 669   data = g_new0 (CloseAsyncData, 1);
 670
 671   data->stream = stream;
 672   data->callback = callback;
 673   data->user_data = user_data;
 674
 675   idle = g_idle_source_new ();
 676   g_source_set_callback (idle, (GSourceFunc)close_async_cb, data, close_async_data_free);
 677   g_source_attach (idle, g_main_context_get_thread_default ());
 678   g_source_unref (idle);
 679 }
 680
 681 static gboolean
 682 g_unix_input_stream_close_finish (GInputStream  *stream,
 683                                   GAsyncResult  *result,
 684                                   GError       **error)
 685 {
 686   /* Failures handled in generic close_finish code */
 687   return TRUE;
 688 }
 689
 690 static gboolean
 691 g_unix_input_stream_pollable_is_readable (GPollableInputStream *stream)
 692 {
 693   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 694   GPollFD poll_fd;
 695   gint result;
 696
 697   poll_fd.fd = unix_stream->priv->fd;
 698   poll_fd.events = G_IO_IN;
 699
 700   do
 701     result = g_poll (&poll_fd, 1, 0);
 702   while (result == -1 && errno == EINTR);
 703
 704   return poll_fd.revents != 0;
 705 }
 706
 707 static GSource *
 708 g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,
 709                                             GCancellable         *cancellable)
 710 {
 711   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 712   GSource *inner_source, *pollable_source;
 713
 714   pollable_source = g_pollable_source_new (G_OBJECT (stream));
 715
 716   inner_source = _g_fd_source_new (unix_stream->priv->fd, G_IO_IN, cancellable);
 717   g_source_set_dummy_callback (inner_source);
 718   g_source_add_child_source (pollable_source, inner_source);
 719   g_source_unref (inner_source);
 720
 721   return pollable_source;
 722 }