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