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, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Author: Alexander Larsson <alexl@redhat.com>
  19  */
  20
  21 #include "config.h"
  22
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <unistd.h>
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <fcntl.h>
  29
  30 #include <glib.h>
  31 #include <glib/gstdio.h>
  32 #include <glib/glib-unix.h>
  33 #include "gioerror.h"
  34 #include "gsimpleasyncresult.h"
  35 #include "gunixinputstream.h"
  36 #include "gcancellable.h"
  37 #include "gasynchelper.h"
  38 #include "gfiledescriptorbased.h"
  39 #include "glibintl.h"
  40
  41
  42 /**
  43  * SECTION:gunixinputstream
  44  * @short_description: Streaming input operations for UNIX file descriptors
  45  * @include: gio/gunixinputstream.h
  46  * @see_also: #GInputStream
  47  *
  48  * #GUnixInputStream implements #GInputStream for reading from a UNIX
  49  * file descriptor, including asynchronous operations. (If the file
  50  * descriptor refers to a socket or pipe, this will use poll() to do
  51  * asynchronous I/O. If it refers to a regular file, it will fall back
  52  * to doing asynchronous I/O in another thread.)
  53  *
  54  * Note that `<gio/gunixinputstream.h>` belongs to the UNIX-specific GIO
  55  * interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config
  56  * file when using it.
  57  */
  58
  59 enum {
  60   PROP_0,
  61   PROP_FD,
  62   PROP_CLOSE_FD
  63 };
  64
  65 struct _GUnixInputStreamPrivate {
  66   int fd;
  67   guint close_fd : 1;
  68   guint is_pipe_or_socket : 1;
  69 };
  70
  71 static void g_unix_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface);
  72 static void g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);
  73
  74 G_DEFINE_TYPE_WITH_CODE (GUnixInputStream, g_unix_input_stream, G_TYPE_INPUT_STREAM,
  75                          G_ADD_PRIVATE (GUnixInputStream)
  76                          G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_INPUT_STREAM,
  77                                                 g_unix_input_stream_pollable_iface_init)
  78                          G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
  79                                                 g_unix_input_stream_file_descriptor_based_iface_init)
  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_class_init (GUnixInputStreamClass *klass)
 123 {
 124   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 125   GInputStreamClass *stream_class = G_INPUT_STREAM_CLASS (klass);
 126
 127   gobject_class->get_property = g_unix_input_stream_get_property;
 128   gobject_class->set_property = g_unix_input_stream_set_property;
 129
 130   stream_class->read_fn = g_unix_input_stream_read;
 131   stream_class->close_fn = g_unix_input_stream_close;
 132   if (0)
 133     {
 134       /* TODO: Implement instead of using fallbacks */
 135       stream_class->skip_async = g_unix_input_stream_skip_async;
 136       stream_class->skip_finish = g_unix_input_stream_skip_finish;
 137     }
 138   stream_class->close_async = g_unix_input_stream_close_async;
 139   stream_class->close_finish = g_unix_input_stream_close_finish;
 140
 141   /**
 142    * GUnixInputStream:fd:
 143    *
 144    * The file descriptor that the stream reads from.
 145    *
 146    * Since: 2.20
 147    */
 148   g_object_class_install_property (gobject_class,
 149                                    PROP_FD,
 150                                    g_param_spec_int ("fd",
 151                                                      P_("File descriptor"),
 152                                                      P_("The file descriptor to read from"),
 153                                                      G_MININT, G_MAXINT, -1,
 154                                                      G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 155
 156   /**
 157    * GUnixInputStream:close-fd:
 158    *
 159    * Whether to close the file descriptor when the stream is closed.
 160    *
 161    * Since: 2.20
 162    */
 163   g_object_class_install_property (gobject_class,
 164                                    PROP_CLOSE_FD,
 165                                    g_param_spec_boolean ("close-fd",
 166                                                          P_("Close file descriptor"),
 167                                                          P_("Whether to close the file descriptor when the stream is closed"),
 168                                                          TRUE,
 169                                                          G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 170 }
 171
 172 static void
 173 g_unix_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface)
 174 {
 175   iface->can_poll = g_unix_input_stream_pollable_can_poll;
 176   iface->is_readable = g_unix_input_stream_pollable_is_readable;
 177   iface->create_source = g_unix_input_stream_pollable_create_source;
 178 }
 179
 180 static void
 181 g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
 182 {
 183   iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_input_stream_get_fd;
 184 }
 185
 186 static void
 187 g_unix_input_stream_set_property (GObject         *object,
 188                                   guint            prop_id,
 189                                   const GValue    *value,
 190                                   GParamSpec      *pspec)
 191 {
 192   GUnixInputStream *unix_stream;
 193
 194   unix_stream = G_UNIX_INPUT_STREAM (object);
 195
 196   switch (prop_id)
 197     {
 198     case PROP_FD:
 199       unix_stream->priv->fd = g_value_get_int (value);
 200       if (lseek (unix_stream->priv->fd, 0, SEEK_CUR) == -1 && errno == ESPIPE)
 201         unix_stream->priv->is_pipe_or_socket = TRUE;
 202       else
 203         unix_stream->priv->is_pipe_or_socket = FALSE;
 204       break;
 205     case PROP_CLOSE_FD:
 206       unix_stream->priv->close_fd = g_value_get_boolean (value);
 207       break;
 208     default:
 209       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 210       break;
 211     }
 212 }
 213
 214 static void
 215 g_unix_input_stream_get_property (GObject    *object,
 216                                   guint       prop_id,
 217                                   GValue     *value,
 218                                   GParamSpec *pspec)
 219 {
 220   GUnixInputStream *unix_stream;
 221
 222   unix_stream = G_UNIX_INPUT_STREAM (object);
 223
 224   switch (prop_id)
 225     {
 226     case PROP_FD:
 227       g_value_set_int (value, unix_stream->priv->fd);
 228       break;
 229     case PROP_CLOSE_FD:
 230       g_value_set_boolean (value, unix_stream->priv->close_fd);
 231       break;
 232     default:
 233       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 234     }
 235 }
 236
 237 static void
 238 g_unix_input_stream_init (GUnixInputStream *unix_stream)
 239 {
 240   unix_stream->priv = g_unix_input_stream_get_instance_private (unix_stream);
 241   unix_stream->priv->fd = -1;
 242   unix_stream->priv->close_fd = TRUE;
 243 }
 244
 245 /**
 246  * g_unix_input_stream_new:
 247  * @fd: a UNIX file descriptor
 248  * @close_fd: %TRUE to close the file descriptor when done
 249  *
 250  * Creates a new #GUnixInputStream for the given @fd.
 251  *
 252  * If @close_fd is %TRUE, the file descriptor will be closed
 253  * when the stream is closed.
 254  *
 255  * Returns: a new #GUnixInputStream
 256  **/
 257 GInputStream *
 258 g_unix_input_stream_new (gint     fd,
 259                          gboolean close_fd)
 260 {
 261   GUnixInputStream *stream;
 262
 263   g_return_val_if_fail (fd != -1, NULL);
 264
 265   stream = g_object_new (G_TYPE_UNIX_INPUT_STREAM,
 266                          "fd", fd,
 267                          "close-fd", close_fd,
 268                          NULL);
 269
 270   return G_INPUT_STREAM (stream);
 271 }
 272
 273 /**
 274  * g_unix_input_stream_set_close_fd:
 275  * @stream: a #GUnixInputStream
 276  * @close_fd: %TRUE to close the file descriptor when done
 277  *
 278  * Sets whether the file descriptor of @stream shall be closed
 279  * when the stream is closed.
 280  *
 281  * Since: 2.20
 282  */
 283 void
 284 g_unix_input_stream_set_close_fd (GUnixInputStream *stream,
 285                                   gboolean          close_fd)
 286 {
 287   g_return_if_fail (G_IS_UNIX_INPUT_STREAM (stream));
 288
 289   close_fd = close_fd != FALSE;
 290   if (stream->priv->close_fd != close_fd)
 291     {
 292       stream->priv->close_fd = close_fd;
 293       g_object_notify (G_OBJECT (stream), "close-fd");
 294     }
 295 }
 296
 297 /**
 298  * g_unix_input_stream_get_close_fd:
 299  * @stream: a #GUnixInputStream
 300  *
 301  * Returns whether the file descriptor of @stream will be
 302  * closed when the stream is closed.
 303  *
 304  * Returns: %TRUE if the file descriptor is closed when done
 305  *
 306  * Since: 2.20
 307  */
 308 gboolean
 309 g_unix_input_stream_get_close_fd (GUnixInputStream *stream)
 310 {
 311   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), FALSE);
 312
 313   return stream->priv->close_fd;
 314 }
 315
 316 /**
 317  * g_unix_input_stream_get_fd:
 318  * @stream: a #GUnixInputStream
 319  *
 320  * Return the UNIX file descriptor that the stream reads from.
 321  *
 322  * Returns: The file descriptor of @stream
 323  *
 324  * Since: 2.20
 325  */
 326 gint
 327 g_unix_input_stream_get_fd (GUnixInputStream *stream)
 328 {
 329   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), -1);
 330
 331   return stream->priv->fd;
 332 }
 333
 334 static gssize
 335 g_unix_input_stream_read (GInputStream  *stream,
 336                           void          *buffer,
 337                           gsize          count,
 338                           GCancellable  *cancellable,
 339                           GError       **error)
 340 {
 341   GUnixInputStream *unix_stream;
 342   gssize res = -1;
 343   GPollFD poll_fds[2];
 344   int nfds;
 345   int poll_ret;
 346
 347   unix_stream = G_UNIX_INPUT_STREAM (stream);
 348
 349   poll_fds[0].fd = unix_stream->priv->fd;
 350   poll_fds[0].events = G_IO_IN;
 351   if (unix_stream->priv->is_pipe_or_socket &&
 352       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
 353     nfds = 2;
 354   else
 355     nfds = 1;
 356
 357   while (1)
 358     {
 359       poll_fds[0].revents = poll_fds[1].revents = 0;
 360       do
 361         poll_ret = g_poll (poll_fds, nfds, -1);
 362       while (poll_ret == -1 && errno == EINTR);
 363
 364       if (poll_ret == -1)
 365         {
 366           int errsv = errno;
 367
 368           g_set_error (error, G_IO_ERROR,
 369                        g_io_error_from_errno (errsv),
 370                        _("Error reading from file descriptor: %s"),
 371                        g_strerror (errsv));
 372           break;
 373         }
 374
 375       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 376         break;
 377
 378       if (!poll_fds[0].revents)
 379         continue;
 380
 381       res = read (unix_stream->priv->fd, buffer, count);
 382       if (res == -1)
 383         {
 384           int errsv = errno;
 385
 386           if (errsv == EINTR || errsv == EAGAIN)
 387             continue;
 388
 389           g_set_error (error, G_IO_ERROR,
 390                        g_io_error_from_errno (errsv),
 391                        _("Error reading from file descriptor: %s"),
 392                        g_strerror (errsv));
 393         }
 394
 395       break;
 396     }
 397
 398   if (nfds == 2)
 399     g_cancellable_release_fd (cancellable);
 400   return res;
 401 }
 402
 403 static gboolean
 404 g_unix_input_stream_close (GInputStream  *stream,
 405                            GCancellable  *cancellable,
 406                            GError       **error)
 407 {
 408   GUnixInputStream *unix_stream;
 409   int res;
 410
 411   unix_stream = G_UNIX_INPUT_STREAM (stream);
 412
 413   if (!unix_stream->priv->close_fd)
 414     return TRUE;
 415
 416   /* This might block during the close. Doesn't seem to be a way to avoid it though. */
 417   res = close (unix_stream->priv->fd);
 418   if (res == -1)
 419     {
 420       int errsv = errno;
 421
 422       g_set_error (error, G_IO_ERROR,
 423                    g_io_error_from_errno (errsv),
 424                    _("Error closing file descriptor: %s"),
 425                    g_strerror (errsv));
 426     }
 427
 428   return res != -1;
 429 }
 430
 431 static void
 432 g_unix_input_stream_skip_async (GInputStream        *stream,
 433                                 gsize                count,
 434                                 int                  io_priority,
 435                                 GCancellable        *cancellable,
 436                                 GAsyncReadyCallback  callback,
 437                                 gpointer             data)
 438 {
 439   g_warn_if_reached ();
 440   /* TODO: Not implemented */
 441 }
 442
 443 static gssize
 444 g_unix_input_stream_skip_finish  (GInputStream  *stream,
 445                                   GAsyncResult  *result,
 446                                   GError       **error)
 447 {
 448   g_warn_if_reached ();
 449   return 0;
 450   /* TODO: Not implemented */
 451 }
 452
 453 static void
 454 g_unix_input_stream_close_async (GInputStream        *stream,
 455                                  int                  io_priority,
 456                                  GCancellable        *cancellable,
 457                                  GAsyncReadyCallback  callback,
 458                                  gpointer             user_data)
 459 {
 460   GTask *task;
 461   GError *error = NULL;
 462
 463   task = g_task_new (stream, cancellable, callback, user_data);
 464   g_task_set_priority (task, io_priority);
 465
 466   if (g_unix_input_stream_close (stream, cancellable, &error))
 467     g_task_return_boolean (task, TRUE);
 468   else
 469     g_task_return_error (task, error);
 470   g_object_unref (task);
 471 }
 472
 473 static gboolean
 474 g_unix_input_stream_close_finish (GInputStream  *stream,
 475                                   GAsyncResult  *result,
 476                                   GError       **error)
 477 {
 478   g_return_val_if_fail (g_task_is_valid (result, stream), FALSE);
 479
 480   return g_task_propagate_boolean (G_TASK (result), error);
 481 }
 482
 483 static gboolean
 484 g_unix_input_stream_pollable_can_poll (GPollableInputStream *stream)
 485 {
 486   return G_UNIX_INPUT_STREAM (stream)->priv->is_pipe_or_socket;
 487 }
 488
 489 static gboolean
 490 g_unix_input_stream_pollable_is_readable (GPollableInputStream *stream)
 491 {
 492   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 493   GPollFD poll_fd;
 494   gint result;
 495
 496   poll_fd.fd = unix_stream->priv->fd;
 497   poll_fd.events = G_IO_IN;
 498   poll_fd.revents = 0;
 499
 500   do
 501     result = g_poll (&poll_fd, 1, 0);
 502   while (result == -1 && errno == EINTR);
 503
 504   return poll_fd.revents != 0;
 505 }
 506
 507 static GSource *
 508 g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,
 509                                             GCancellable         *cancellable)
 510 {
 511   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 512   GSource *inner_source, *cancellable_source, *pollable_source;
 513
 514   pollable_source = g_pollable_source_new (G_OBJECT (stream));
 515
 516   inner_source = g_unix_fd_source_new (unix_stream->priv->fd, G_IO_IN);
 517   g_source_set_dummy_callback (inner_source);
 518   g_source_add_child_source (pollable_source, inner_source);
 519   g_source_unref (inner_source);
 520
 521   if (cancellable)
 522     {
 523       cancellable_source = g_cancellable_source_new (cancellable);
 524       g_source_set_dummy_callback (cancellable_source);
 525       g_source_add_child_source (pollable_source, cancellable_source);
 526       g_source_unref (cancellable_source);
 527     }
 528
 529   return pollable_source;
 530 }