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_skip_async   (GInputStream         *stream,
  99                                                   gsize                 count,
 100                                                   int                   io_priority,
 101                                                   GCancellable         *cancellable,
 102                                                   GAsyncReadyCallback   callback,
 103                                                   gpointer              data);
 104 static gssize   g_unix_input_stream_skip_finish  (GInputStream         *stream,
 105                                                   GAsyncResult         *result,
 106                                                   GError              **error);
 107 static void     g_unix_input_stream_close_async  (GInputStream         *stream,
 108                                                   int                   io_priority,
 109                                                   GCancellable         *cancellable,
 110                                                   GAsyncReadyCallback   callback,
 111                                                   gpointer              data);
 112 static gboolean g_unix_input_stream_close_finish (GInputStream         *stream,
 113                                                   GAsyncResult         *result,
 114                                                   GError              **error);
 115
 116 static gboolean g_unix_input_stream_pollable_can_poll      (GPollableInputStream *stream);
 117 static gboolean g_unix_input_stream_pollable_is_readable   (GPollableInputStream *stream);
 118 static GSource *g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,
 119                                                             GCancellable         *cancellable);
 120
 121 static void
 122 g_unix_input_stream_finalize (GObject *object)
 123 {
 124   G_OBJECT_CLASS (g_unix_input_stream_parent_class)->finalize (object);
 125 }
 126
 127 static void
 128 g_unix_input_stream_class_init (GUnixInputStreamClass *klass)
 129 {
 130   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 131   GInputStreamClass *stream_class = G_INPUT_STREAM_CLASS (klass);
 132
 133   g_type_class_add_private (klass, sizeof (GUnixInputStreamPrivate));
 134
 135   gobject_class->get_property = g_unix_input_stream_get_property;
 136   gobject_class->set_property = g_unix_input_stream_set_property;
 137   gobject_class->finalize = g_unix_input_stream_finalize;
 138
 139   stream_class->read_fn = g_unix_input_stream_read;
 140   stream_class->close_fn = g_unix_input_stream_close;
 141   if (0)
 142     {
 143       /* TODO: Implement instead of using fallbacks */
 144       stream_class->skip_async = g_unix_input_stream_skip_async;
 145       stream_class->skip_finish = g_unix_input_stream_skip_finish;
 146     }
 147   stream_class->close_async = g_unix_input_stream_close_async;
 148   stream_class->close_finish = g_unix_input_stream_close_finish;
 149
 150   /**
 151    * GUnixInputStream:fd:
 152    *
 153    * The file descriptor that the stream reads from.
 154    *
 155    * Since: 2.20
 156    */
 157   g_object_class_install_property (gobject_class,
 158                                    PROP_FD,
 159                                    g_param_spec_int ("fd",
 160                                                      P_("File descriptor"),
 161                                                      P_("The file descriptor to read from"),
 162                                                      G_MININT, G_MAXINT, -1,
 163                                                      G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 164
 165   /**
 166    * GUnixInputStream:close-fd:
 167    *
 168    * Whether to close the file descriptor when the stream is closed.
 169    *
 170    * Since: 2.20
 171    */
 172   g_object_class_install_property (gobject_class,
 173                                    PROP_CLOSE_FD,
 174                                    g_param_spec_boolean ("close-fd",
 175                                                          P_("Close file descriptor"),
 176                                                          P_("Whether to close the file descriptor when the stream is closed"),
 177                                                          TRUE,
 178                                                          G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 179 }
 180
 181 static void
 182 g_unix_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface)
 183 {
 184   iface->can_poll = g_unix_input_stream_pollable_can_poll;
 185   iface->is_readable = g_unix_input_stream_pollable_is_readable;
 186   iface->create_source = g_unix_input_stream_pollable_create_source;
 187 }
 188
 189 static void
 190 g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
 191 {
 192   iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_input_stream_get_fd;
 193 }
 194
 195 static void
 196 g_unix_input_stream_set_property (GObject         *object,
 197                                   guint            prop_id,
 198                                   const GValue    *value,
 199                                   GParamSpec      *pspec)
 200 {
 201   GUnixInputStream *unix_stream;
 202
 203   unix_stream = G_UNIX_INPUT_STREAM (object);
 204
 205   switch (prop_id)
 206     {
 207     case PROP_FD:
 208       unix_stream->priv->fd = g_value_get_int (value);
 209       if (lseek (unix_stream->priv->fd, 0, SEEK_CUR) == -1 && errno == ESPIPE)
 210         unix_stream->priv->is_pipe_or_socket = TRUE;
 211       else
 212         unix_stream->priv->is_pipe_or_socket = FALSE;
 213       break;
 214     case PROP_CLOSE_FD:
 215       unix_stream->priv->close_fd = g_value_get_boolean (value);
 216       break;
 217     default:
 218       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 219       break;
 220     }
 221 }
 222
 223 static void
 224 g_unix_input_stream_get_property (GObject    *object,
 225                                   guint       prop_id,
 226                                   GValue     *value,
 227                                   GParamSpec *pspec)
 228 {
 229   GUnixInputStream *unix_stream;
 230
 231   unix_stream = G_UNIX_INPUT_STREAM (object);
 232
 233   switch (prop_id)
 234     {
 235     case PROP_FD:
 236       g_value_set_int (value, unix_stream->priv->fd);
 237       break;
 238     case PROP_CLOSE_FD:
 239       g_value_set_boolean (value, unix_stream->priv->close_fd);
 240       break;
 241     default:
 242       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 243     }
 244 }
 245
 246 static void
 247 g_unix_input_stream_init (GUnixInputStream *unix_stream)
 248 {
 249   unix_stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (unix_stream,
 250                                                    G_TYPE_UNIX_INPUT_STREAM,
 251                                                    GUnixInputStreamPrivate);
 252
 253   unix_stream->priv->fd = -1;
 254   unix_stream->priv->close_fd = TRUE;
 255 }
 256
 257 /**
 258  * g_unix_input_stream_new:
 259  * @fd: a UNIX file descriptor
 260  * @close_fd: %TRUE to close the file descriptor when done
 261  *
 262  * Creates a new #GUnixInputStream for the given @fd.
 263  *
 264  * If @close_fd is %TRUE, the file descriptor will be closed
 265  * when the stream is closed.
 266  *
 267  * Returns: a new #GUnixInputStream
 268  **/
 269 GInputStream *
 270 g_unix_input_stream_new (gint     fd,
 271                          gboolean close_fd)
 272 {
 273   GUnixInputStream *stream;
 274
 275   g_return_val_if_fail (fd != -1, NULL);
 276
 277   stream = g_object_new (G_TYPE_UNIX_INPUT_STREAM,
 278                          "fd", fd,
 279                          "close-fd", close_fd,
 280                          NULL);
 281
 282   return G_INPUT_STREAM (stream);
 283 }
 284
 285 /**
 286  * g_unix_input_stream_set_close_fd:
 287  * @stream: a #GUnixInputStream
 288  * @close_fd: %TRUE to close the file descriptor when done
 289  *
 290  * Sets whether the file descriptor of @stream shall be closed
 291  * when the stream is closed.
 292  *
 293  * Since: 2.20
 294  */
 295 void
 296 g_unix_input_stream_set_close_fd (GUnixInputStream *stream,
 297                                   gboolean          close_fd)
 298 {
 299   g_return_if_fail (G_IS_UNIX_INPUT_STREAM (stream));
 300
 301   close_fd = close_fd != FALSE;
 302   if (stream->priv->close_fd != close_fd)
 303     {
 304       stream->priv->close_fd = close_fd;
 305       g_object_notify (G_OBJECT (stream), "close-fd");
 306     }
 307 }
 308
 309 /**
 310  * g_unix_input_stream_get_close_fd:
 311  * @stream: a #GUnixInputStream
 312  *
 313  * Returns whether the file descriptor of @stream will be
 314  * closed when the stream is closed.
 315  *
 316  * Return value: %TRUE if the file descriptor is closed when done
 317  *
 318  * Since: 2.20
 319  */
 320 gboolean
 321 g_unix_input_stream_get_close_fd (GUnixInputStream *stream)
 322 {
 323   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), FALSE);
 324
 325   return stream->priv->close_fd;
 326 }
 327
 328 /**
 329  * g_unix_input_stream_get_fd:
 330  * @stream: a #GUnixInputStream
 331  *
 332  * Return the UNIX file descriptor that the stream reads from.
 333  *
 334  * Return value: The file descriptor of @stream
 335  *
 336  * Since: 2.20
 337  */
 338 gint
 339 g_unix_input_stream_get_fd (GUnixInputStream *stream)
 340 {
 341   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), -1);
 342
 343   return stream->priv->fd;
 344 }
 345
 346 static gssize
 347 g_unix_input_stream_read (GInputStream  *stream,
 348                           void          *buffer,
 349                           gsize          count,
 350                           GCancellable  *cancellable,
 351                           GError       **error)
 352 {
 353   GUnixInputStream *unix_stream;
 354   gssize res = -1;
 355   GPollFD poll_fds[2];
 356   int nfds;
 357   int poll_ret;
 358
 359   unix_stream = G_UNIX_INPUT_STREAM (stream);
 360
 361   poll_fds[0].fd = unix_stream->priv->fd;
 362   poll_fds[0].events = G_IO_IN;
 363   if (unix_stream->priv->is_pipe_or_socket &&
 364       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
 365     nfds = 2;
 366   else
 367     nfds = 1;
 368
 369   while (1)
 370     {
 371       poll_fds[0].revents = poll_fds[1].revents = 0;
 372       do
 373         poll_ret = g_poll (poll_fds, nfds, -1);
 374       while (poll_ret == -1 && errno == EINTR);
 375
 376       if (poll_ret == -1)
 377         {
 378           int errsv = errno;
 379
 380           g_set_error (error, G_IO_ERROR,
 381                        g_io_error_from_errno (errsv),
 382                        _("Error reading from file descriptor: %s"),
 383                        g_strerror (errsv));
 384           break;
 385         }
 386
 387       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 388         break;
 389
 390       if (!poll_fds[0].revents)
 391         continue;
 392
 393       res = read (unix_stream->priv->fd, buffer, count);
 394       if (res == -1)
 395         {
 396           int errsv = errno;
 397
 398           if (errsv == EINTR || errsv == EAGAIN)
 399             continue;
 400
 401           g_set_error (error, G_IO_ERROR,
 402                        g_io_error_from_errno (errsv),
 403                        _("Error reading from file descriptor: %s"),
 404                        g_strerror (errsv));
 405         }
 406
 407       break;
 408     }
 409
 410   if (nfds == 2)
 411     g_cancellable_release_fd (cancellable);
 412   return res;
 413 }
 414
 415 static gboolean
 416 g_unix_input_stream_close (GInputStream  *stream,
 417                            GCancellable  *cancellable,
 418                            GError       **error)
 419 {
 420   GUnixInputStream *unix_stream;
 421   int res;
 422
 423   unix_stream = G_UNIX_INPUT_STREAM (stream);
 424
 425   if (!unix_stream->priv->close_fd)
 426     return TRUE;
 427
 428   while (1)
 429     {
 430       /* This might block during the close. Doesn't seem to be a way to avoid it though. */
 431       res = close (unix_stream->priv->fd);
 432       if (res == -1)
 433         {
 434           int errsv = errno;
 435
 436           g_set_error (error, G_IO_ERROR,
 437                        g_io_error_from_errno (errsv),
 438                        _("Error closing file descriptor: %s"),
 439                        g_strerror (errsv));
 440         }
 441       break;
 442     }
 443
 444   return res != -1;
 445 }
 446
 447 static void
 448 g_unix_input_stream_skip_async (GInputStream        *stream,
 449                                 gsize                count,
 450                                 int                  io_priority,
 451                                 GCancellable        *cancellable,
 452                                 GAsyncReadyCallback  callback,
 453                                 gpointer             data)
 454 {
 455   g_warn_if_reached ();
 456   /* TODO: Not implemented */
 457 }
 458
 459 static gssize
 460 g_unix_input_stream_skip_finish  (GInputStream  *stream,
 461                                   GAsyncResult  *result,
 462                                   GError       **error)
 463 {
 464   g_warn_if_reached ();
 465   return 0;
 466   /* TODO: Not implemented */
 467 }
 468
 469
 470 typedef struct {
 471   GInputStream *stream;
 472   GAsyncReadyCallback callback;
 473   gpointer user_data;
 474 } CloseAsyncData;
 475
 476 static void
 477 close_async_data_free (gpointer _data)
 478 {
 479   CloseAsyncData *data = _data;
 480
 481   g_free (data);
 482 }
 483
 484 static gboolean
 485 close_async_cb (CloseAsyncData *data)
 486 {
 487   GUnixInputStream *unix_stream;
 488   GSimpleAsyncResult *simple;
 489   GError *error = NULL;
 490   gboolean result;
 491   int res;
 492
 493   unix_stream = G_UNIX_INPUT_STREAM (data->stream);
 494
 495   if (!unix_stream->priv->close_fd)
 496     {
 497       result = TRUE;
 498       goto out;
 499     }
 500
 501   while (1)
 502     {
 503       res = close (unix_stream->priv->fd);
 504       if (res == -1)
 505         {
 506           int errsv = errno;
 507
 508           g_set_error (&error, G_IO_ERROR,
 509                        g_io_error_from_errno (errsv),
 510                        _("Error closing file descriptor: %s"),
 511                        g_strerror (errsv));
 512         }
 513       break;
 514     }
 515
 516   result = res != -1;
 517
 518  out:
 519   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 520                                       data->callback,
 521                                       data->user_data,
 522                                       g_unix_input_stream_close_async);
 523
 524   if (!result)
 525     g_simple_async_result_take_error (simple, error);
 526
 527   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 528   g_simple_async_result_complete (simple);
 529   g_object_unref (simple);
 530
 531   return FALSE;
 532 }
 533
 534 static void
 535 g_unix_input_stream_close_async (GInputStream        *stream,
 536                                  int                  io_priority,
 537                                  GCancellable        *cancellable,
 538                                  GAsyncReadyCallback  callback,
 539                                  gpointer             user_data)
 540 {
 541   GSource *idle;
 542   CloseAsyncData *data;
 543
 544   data = g_new0 (CloseAsyncData, 1);
 545
 546   data->stream = stream;
 547   data->callback = callback;
 548   data->user_data = user_data;
 549
 550   idle = g_idle_source_new ();
 551   g_source_set_callback (idle, (GSourceFunc)close_async_cb, data, close_async_data_free);
 552   g_source_attach (idle, g_main_context_get_thread_default ());
 553   g_source_unref (idle);
 554 }
 555
 556 static gboolean
 557 g_unix_input_stream_close_finish (GInputStream  *stream,
 558                                   GAsyncResult  *result,
 559                                   GError       **error)
 560 {
 561   /* Failures handled in generic close_finish code */
 562   return TRUE;
 563 }
 564
 565 static gboolean
 566 g_unix_input_stream_pollable_can_poll (GPollableInputStream *stream)
 567 {
 568   return G_UNIX_INPUT_STREAM (stream)->priv->is_pipe_or_socket;
 569 }
 570
 571 static gboolean
 572 g_unix_input_stream_pollable_is_readable (GPollableInputStream *stream)
 573 {
 574   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 575   GPollFD poll_fd;
 576   gint result;
 577
 578   poll_fd.fd = unix_stream->priv->fd;
 579   poll_fd.events = G_IO_IN;
 580
 581   do
 582     result = g_poll (&poll_fd, 1, 0);
 583   while (result == -1 && errno == EINTR);
 584
 585   return poll_fd.revents != 0;
 586 }
 587
 588 static GSource *
 589 g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,
 590                                             GCancellable         *cancellable)
 591 {
 592   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 593   GSource *inner_source, *pollable_source;
 594
 595   pollable_source = g_pollable_source_new (G_OBJECT (stream));
 596
 597   inner_source = _g_fd_source_new (unix_stream->priv->fd, G_IO_IN, cancellable);
 598   g_source_set_dummy_callback (inner_source);
 599   g_source_add_child_source (pollable_source, inner_source);
 600   g_source_unref (inner_source);
 601
 602   return pollable_source;
 603 }