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 = -1;
 365   GPollFD poll_fds[2];
 366   int nfds;
 367   int poll_ret;
 368
 369   unix_stream = G_UNIX_INPUT_STREAM (stream);
 370
 371   poll_fds[0].fd = unix_stream->priv->fd;
 372   poll_fds[0].events = G_IO_IN;
 373   if (unix_stream->priv->is_pipe_or_socket &&
 374       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
 375     nfds = 2;
 376   else
 377     nfds = 1;
 378
 379   while (1)
 380     {
 381       poll_fds[0].revents = poll_fds[1].revents = 0;
 382       do
 383         poll_ret = g_poll (poll_fds, nfds, -1);
 384       while (poll_ret == -1 && errno == EINTR);
 385
 386       if (poll_ret == -1)
 387         {
 388           int errsv = errno;
 389
 390           g_set_error (error, G_IO_ERROR,
 391                        g_io_error_from_errno (errsv),
 392                        _("Error reading from file descriptor: %s"),
 393                        g_strerror (errsv));
 394           break;
 395         }
 396
 397       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 398         break;
 399
 400       if (!poll_fds[0].revents)
 401         continue;
 402
 403       res = read (unix_stream->priv->fd, buffer, count);
 404       if (res == -1)
 405         {
 406           int errsv = errno;
 407
 408           if (errsv == EINTR || errsv == EAGAIN)
 409             continue;
 410
 411           g_set_error (error, G_IO_ERROR,
 412                        g_io_error_from_errno (errsv),
 413                        _("Error reading from file descriptor: %s"),
 414                        g_strerror (errsv));
 415         }
 416
 417       break;
 418     }
 419
 420   if (nfds == 2)
 421     g_cancellable_release_fd (cancellable);
 422   return res;
 423 }
 424
 425 static gboolean
 426 g_unix_input_stream_close (GInputStream  *stream,
 427                            GCancellable  *cancellable,
 428                            GError       **error)
 429 {
 430   GUnixInputStream *unix_stream;
 431   int res;
 432
 433   unix_stream = G_UNIX_INPUT_STREAM (stream);
 434
 435   if (!unix_stream->priv->close_fd)
 436     return TRUE;
 437
 438   while (1)
 439     {
 440       /* This might block during the close. Doesn't seem to be a way to avoid it though. */
 441       res = close (unix_stream->priv->fd);
 442       if (res == -1)
 443         {
 444           int errsv = errno;
 445
 446           g_set_error (error, G_IO_ERROR,
 447                        g_io_error_from_errno (errsv),
 448                        _("Error closing file descriptor: %s"),
 449                        g_strerror (errsv));
 450         }
 451       break;
 452     }
 453
 454   return res != -1;
 455 }
 456
 457 typedef struct {
 458   gsize count;
 459   void *buffer;
 460   GAsyncReadyCallback callback;
 461   gpointer user_data;
 462   GCancellable *cancellable;
 463   GUnixInputStream *stream;
 464 } ReadAsyncData;
 465
 466 static gboolean
 467 read_async_cb (int            fd,
 468                GIOCondition   condition,
 469                ReadAsyncData *data)
 470 {
 471   GSimpleAsyncResult *simple;
 472   GError *error = NULL;
 473   gssize count_read;
 474
 475   /* We know that we can read from fd once without blocking */
 476   while (1)
 477     {
 478       if (g_cancellable_set_error_if_cancelled (data->cancellable, &error))
 479         {
 480           count_read = -1;
 481           break;
 482         }
 483       count_read = read (data->stream->priv->fd, data->buffer, data->count);
 484       if (count_read == -1)
 485         {
 486           int errsv = errno;
 487
 488           if (errsv == EINTR || errsv == EAGAIN)
 489             return TRUE;
 490
 491           g_set_error (&error, G_IO_ERROR,
 492                        g_io_error_from_errno (errsv),
 493                        _("Error reading from file descriptor: %s"),
 494                        g_strerror (errsv));
 495         }
 496       break;
 497     }
 498
 499   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 500                                       data->callback,
 501                                       data->user_data,
 502                                       g_unix_input_stream_read_async);
 503
 504   g_simple_async_result_set_op_res_gssize (simple, count_read);
 505
 506   if (count_read == -1)
 507     g_simple_async_result_take_error (simple, error);
 508
 509   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 510   g_simple_async_result_complete (simple);
 511   g_object_unref (simple);
 512
 513   return FALSE;
 514 }
 515
 516 static void
 517 g_unix_input_stream_read_async (GInputStream        *stream,
 518                                 void                *buffer,
 519                                 gsize                count,
 520                                 int                  io_priority,
 521                                 GCancellable        *cancellable,
 522                                 GAsyncReadyCallback  callback,
 523                                 gpointer             user_data)
 524 {
 525   GSource *source;
 526   GUnixInputStream *unix_stream;
 527   ReadAsyncData *data;
 528
 529   unix_stream = G_UNIX_INPUT_STREAM (stream);
 530
 531   if (!unix_stream->priv->is_pipe_or_socket)
 532     {
 533       G_INPUT_STREAM_CLASS (g_unix_input_stream_parent_class)->
 534         read_async (stream, buffer, count, io_priority,
 535                     cancellable, callback, user_data);
 536       return;
 537     }
 538
 539   data = g_new0 (ReadAsyncData, 1);
 540   data->count = count;
 541   data->buffer = buffer;
 542   data->callback = callback;
 543   data->user_data = user_data;
 544   data->cancellable = cancellable;
 545   data->stream = unix_stream;
 546
 547   source = _g_fd_source_new (unix_stream->priv->fd,
 548                              G_IO_IN,
 549                              cancellable);
 550   g_source_set_name (source, "GUnixInputStream");
 551
 552   g_source_set_callback (source, (GSourceFunc)read_async_cb, data, g_free);
 553   g_source_attach (source, g_main_context_get_thread_default ());
 554
 555   g_source_unref (source);
 556 }
 557
 558 static gssize
 559 g_unix_input_stream_read_finish (GInputStream  *stream,
 560                                  GAsyncResult  *result,
 561                                  GError       **error)
 562 {
 563   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 564   GSimpleAsyncResult *simple;
 565   gssize nread;
 566
 567   if (!unix_stream->priv->is_pipe_or_socket)
 568     {
 569       return G_INPUT_STREAM_CLASS (g_unix_input_stream_parent_class)->
 570         read_finish (stream, result, error);
 571     }
 572
 573   simple = G_SIMPLE_ASYNC_RESULT (result);
 574   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_unix_input_stream_read_async);
 575
 576   nread = g_simple_async_result_get_op_res_gssize (simple);
 577   return nread;
 578 }
 579
 580 static void
 581 g_unix_input_stream_skip_async (GInputStream        *stream,
 582                                 gsize                count,
 583                                 int                  io_priority,
 584                                 GCancellable        *cancellable,
 585                                 GAsyncReadyCallback  callback,
 586                                 gpointer             data)
 587 {
 588   g_warn_if_reached ();
 589   /* TODO: Not implemented */
 590 }
 591
 592 static gssize
 593 g_unix_input_stream_skip_finish  (GInputStream  *stream,
 594                                   GAsyncResult  *result,
 595                                   GError       **error)
 596 {
 597   g_warn_if_reached ();
 598   return 0;
 599   /* TODO: Not implemented */
 600 }
 601
 602
 603 typedef struct {
 604   GInputStream *stream;
 605   GAsyncReadyCallback callback;
 606   gpointer user_data;
 607 } CloseAsyncData;
 608
 609 static void
 610 close_async_data_free (gpointer _data)
 611 {
 612   CloseAsyncData *data = _data;
 613
 614   g_free (data);
 615 }
 616
 617 static gboolean
 618 close_async_cb (CloseAsyncData *data)
 619 {
 620   GUnixInputStream *unix_stream;
 621   GSimpleAsyncResult *simple;
 622   GError *error = NULL;
 623   gboolean result;
 624   int res;
 625
 626   unix_stream = G_UNIX_INPUT_STREAM (data->stream);
 627
 628   if (!unix_stream->priv->close_fd)
 629     {
 630       result = TRUE;
 631       goto out;
 632     }
 633
 634   while (1)
 635     {
 636       res = close (unix_stream->priv->fd);
 637       if (res == -1)
 638         {
 639           int errsv = errno;
 640
 641           g_set_error (&error, G_IO_ERROR,
 642                        g_io_error_from_errno (errsv),
 643                        _("Error closing file descriptor: %s"),
 644                        g_strerror (errsv));
 645         }
 646       break;
 647     }
 648
 649   result = res != -1;
 650
 651  out:
 652   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 653                                       data->callback,
 654                                       data->user_data,
 655                                       g_unix_input_stream_close_async);
 656
 657   if (!result)
 658     g_simple_async_result_take_error (simple, error);
 659
 660   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 661   g_simple_async_result_complete (simple);
 662   g_object_unref (simple);
 663
 664   return FALSE;
 665 }
 666
 667 static void
 668 g_unix_input_stream_close_async (GInputStream        *stream,
 669                                  int                  io_priority,
 670                                  GCancellable        *cancellable,
 671                                  GAsyncReadyCallback  callback,
 672                                  gpointer             user_data)
 673 {
 674   GSource *idle;
 675   CloseAsyncData *data;
 676
 677   data = g_new0 (CloseAsyncData, 1);
 678
 679   data->stream = stream;
 680   data->callback = callback;
 681   data->user_data = user_data;
 682
 683   idle = g_idle_source_new ();
 684   g_source_set_callback (idle, (GSourceFunc)close_async_cb, data, close_async_data_free);
 685   g_source_attach (idle, g_main_context_get_thread_default ());
 686   g_source_unref (idle);
 687 }
 688
 689 static gboolean
 690 g_unix_input_stream_close_finish (GInputStream  *stream,
 691                                   GAsyncResult  *result,
 692                                   GError       **error)
 693 {
 694   /* Failures handled in generic close_finish code */
 695   return TRUE;
 696 }
 697
 698 static gboolean
 699 g_unix_input_stream_pollable_is_readable (GPollableInputStream *stream)
 700 {
 701   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 702   GPollFD poll_fd;
 703   gint result;
 704
 705   poll_fd.fd = unix_stream->priv->fd;
 706   poll_fd.events = G_IO_IN;
 707
 708   do
 709     result = g_poll (&poll_fd, 1, 0);
 710   while (result == -1 && errno == EINTR);
 711
 712   return poll_fd.revents != 0;
 713 }
 714
 715 static GSource *
 716 g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,
 717                                             GCancellable         *cancellable)
 718 {
 719   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 720   GSource *inner_source, *pollable_source;
 721
 722   pollable_source = g_pollable_source_new (G_OBJECT (stream));
 723
 724   inner_source = _g_fd_source_new (unix_stream->priv->fd, G_IO_IN, cancellable);
 725   g_source_set_dummy_callback (inner_source);
 726   g_source_add_child_source (pollable_source, inner_source);
 727   g_source_unref (inner_source);
 728
 729   return pollable_source;
 730 }