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 "gunixinputstream.h"
  35 #include "gcancellable.h"
  36 #include "gasynchelper.h"
  37 #include "gfiledescriptorbased.h"
  38 #include "glibintl.h"
  39
  40
  41 /**
  42  * SECTION:gunixinputstream
  43  * @short_description: Streaming input operations for UNIX file descriptors
  44  * @include: gio/gunixinputstream.h
  45  * @see_also: #GInputStream
  46  *
  47  * #GUnixInputStream implements #GInputStream for reading from a UNIX
  48  * file descriptor, including asynchronous operations. (If the file
  49  * descriptor refers to a socket or pipe, this will use poll() to do
  50  * asynchronous I/O. If it refers to a regular file, it will fall back
  51  * to doing asynchronous I/O in another thread.)
  52  *
  53  * Note that `<gio/gunixinputstream.h>` belongs to the UNIX-specific GIO
  54  * interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config
  55  * file when using it.
  56  */
  57
  58 enum {
  59   PROP_0,
  60   PROP_FD,
  61   PROP_CLOSE_FD
  62 };
  63
  64 struct _GUnixInputStreamPrivate {
  65   int fd;
  66   guint close_fd : 1;
  67   guint is_pipe_or_socket : 1;
  68 };
  69
  70 static void g_unix_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface);
  71 static void g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);
  72
  73 G_DEFINE_TYPE_WITH_CODE (GUnixInputStream, g_unix_input_stream, G_TYPE_INPUT_STREAM,
  74                          G_ADD_PRIVATE (GUnixInputStream)
  75                          G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_INPUT_STREAM,
  76                                                 g_unix_input_stream_pollable_iface_init)
  77                          G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
  78                                                 g_unix_input_stream_file_descriptor_based_iface_init)
  79                          )
  80
  81 static void     g_unix_input_stream_set_property (GObject              *object,
  82                                                   guint                 prop_id,
  83                                                   const GValue         *value,
  84                                                   GParamSpec           *pspec);
  85 static void     g_unix_input_stream_get_property (GObject              *object,
  86                                                   guint                 prop_id,
  87                                                   GValue               *value,
  88                                                   GParamSpec           *pspec);
  89 static gssize   g_unix_input_stream_read         (GInputStream         *stream,
  90                                                   void                 *buffer,
  91                                                   gsize                 count,
  92                                                   GCancellable         *cancellable,
  93                                                   GError              **error);
  94 static gboolean g_unix_input_stream_close        (GInputStream         *stream,
  95                                                   GCancellable         *cancellable,
  96                                                   GError              **error);
  97 static void     g_unix_input_stream_skip_async   (GInputStream         *stream,
  98                                                   gsize                 count,
  99                                                   int                   io_priority,
 100                                                   GCancellable         *cancellable,
 101                                                   GAsyncReadyCallback   callback,
 102                                                   gpointer              data);
 103 static gssize   g_unix_input_stream_skip_finish  (GInputStream         *stream,
 104                                                   GAsyncResult         *result,
 105                                                   GError              **error);
 106 static void     g_unix_input_stream_close_async  (GInputStream         *stream,
 107                                                   int                   io_priority,
 108                                                   GCancellable         *cancellable,
 109                                                   GAsyncReadyCallback   callback,
 110                                                   gpointer              data);
 111 static gboolean g_unix_input_stream_close_finish (GInputStream         *stream,
 112                                                   GAsyncResult         *result,
 113                                                   GError              **error);
 114
 115 static gboolean g_unix_input_stream_pollable_can_poll      (GPollableInputStream *stream);
 116 static gboolean g_unix_input_stream_pollable_is_readable   (GPollableInputStream *stream);
 117 static GSource *g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,
 118                                                             GCancellable         *cancellable);
 119
 120 static void
 121 g_unix_input_stream_class_init (GUnixInputStreamClass *klass)
 122 {
 123   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 124   GInputStreamClass *stream_class = G_INPUT_STREAM_CLASS (klass);
 125
 126   gobject_class->get_property = g_unix_input_stream_get_property;
 127   gobject_class->set_property = g_unix_input_stream_set_property;
 128
 129   stream_class->read_fn = g_unix_input_stream_read;
 130   stream_class->close_fn = g_unix_input_stream_close;
 131   if (0)
 132     {
 133       /* TODO: Implement instead of using fallbacks */
 134       stream_class->skip_async = g_unix_input_stream_skip_async;
 135       stream_class->skip_finish = g_unix_input_stream_skip_finish;
 136     }
 137   stream_class->close_async = g_unix_input_stream_close_async;
 138   stream_class->close_finish = g_unix_input_stream_close_finish;
 139
 140   /**
 141    * GUnixInputStream:fd:
 142    *
 143    * The file descriptor that the stream reads from.
 144    *
 145    * Since: 2.20
 146    */
 147   g_object_class_install_property (gobject_class,
 148                                    PROP_FD,
 149                                    g_param_spec_int ("fd",
 150                                                      P_("File descriptor"),
 151                                                      P_("The file descriptor to read from"),
 152                                                      G_MININT, G_MAXINT, -1,
 153                                                      G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 154
 155   /**
 156    * GUnixInputStream:close-fd:
 157    *
 158    * Whether to close the file descriptor when the stream is closed.
 159    *
 160    * Since: 2.20
 161    */
 162   g_object_class_install_property (gobject_class,
 163                                    PROP_CLOSE_FD,
 164                                    g_param_spec_boolean ("close-fd",
 165                                                          P_("Close file descriptor"),
 166                                                          P_("Whether to close the file descriptor when the stream is closed"),
 167                                                          TRUE,
 168                                                          G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 169 }
 170
 171 static void
 172 g_unix_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface)
 173 {
 174   iface->can_poll = g_unix_input_stream_pollable_can_poll;
 175   iface->is_readable = g_unix_input_stream_pollable_is_readable;
 176   iface->create_source = g_unix_input_stream_pollable_create_source;
 177 }
 178
 179 static void
 180 g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
 181 {
 182   iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_input_stream_get_fd;
 183 }
 184
 185 static void
 186 g_unix_input_stream_set_property (GObject         *object,
 187                                   guint            prop_id,
 188                                   const GValue    *value,
 189                                   GParamSpec      *pspec)
 190 {
 191   GUnixInputStream *unix_stream;
 192
 193   unix_stream = G_UNIX_INPUT_STREAM (object);
 194
 195   switch (prop_id)
 196     {
 197     case PROP_FD:
 198       unix_stream->priv->fd = g_value_get_int (value);
 199       if (lseek (unix_stream->priv->fd, 0, SEEK_CUR) == -1 && errno == ESPIPE)
 200         unix_stream->priv->is_pipe_or_socket = TRUE;
 201       else
 202         unix_stream->priv->is_pipe_or_socket = FALSE;
 203       break;
 204     case PROP_CLOSE_FD:
 205       unix_stream->priv->close_fd = g_value_get_boolean (value);
 206       break;
 207     default:
 208       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 209       break;
 210     }
 211 }
 212
 213 static void
 214 g_unix_input_stream_get_property (GObject    *object,
 215                                   guint       prop_id,
 216                                   GValue     *value,
 217                                   GParamSpec *pspec)
 218 {
 219   GUnixInputStream *unix_stream;
 220
 221   unix_stream = G_UNIX_INPUT_STREAM (object);
 222
 223   switch (prop_id)
 224     {
 225     case PROP_FD:
 226       g_value_set_int (value, unix_stream->priv->fd);
 227       break;
 228     case PROP_CLOSE_FD:
 229       g_value_set_boolean (value, unix_stream->priv->close_fd);
 230       break;
 231     default:
 232       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 233     }
 234 }
 235
 236 static void
 237 g_unix_input_stream_init (GUnixInputStream *unix_stream)
 238 {
 239   unix_stream->priv = g_unix_input_stream_get_instance_private (unix_stream);
 240   unix_stream->priv->fd = -1;
 241   unix_stream->priv->close_fd = TRUE;
 242 }
 243
 244 /**
 245  * g_unix_input_stream_new:
 246  * @fd: a UNIX file descriptor
 247  * @close_fd: %TRUE to close the file descriptor when done
 248  *
 249  * Creates a new #GUnixInputStream for the given @fd.
 250  *
 251  * If @close_fd is %TRUE, the file descriptor will be closed
 252  * when the stream is closed.
 253  *
 254  * Returns: a new #GUnixInputStream
 255  **/
 256 GInputStream *
 257 g_unix_input_stream_new (gint     fd,
 258                          gboolean close_fd)
 259 {
 260   GUnixInputStream *stream;
 261
 262   g_return_val_if_fail (fd != -1, NULL);
 263
 264   stream = g_object_new (G_TYPE_UNIX_INPUT_STREAM,
 265                          "fd", fd,
 266                          "close-fd", close_fd,
 267                          NULL);
 268
 269   return G_INPUT_STREAM (stream);
 270 }
 271
 272 /**
 273  * g_unix_input_stream_set_close_fd:
 274  * @stream: a #GUnixInputStream
 275  * @close_fd: %TRUE to close the file descriptor when done
 276  *
 277  * Sets whether the file descriptor of @stream shall be closed
 278  * when the stream is closed.
 279  *
 280  * Since: 2.20
 281  */
 282 void
 283 g_unix_input_stream_set_close_fd (GUnixInputStream *stream,
 284                                   gboolean          close_fd)
 285 {
 286   g_return_if_fail (G_IS_UNIX_INPUT_STREAM (stream));
 287
 288   close_fd = close_fd != FALSE;
 289   if (stream->priv->close_fd != close_fd)
 290     {
 291       stream->priv->close_fd = close_fd;
 292       g_object_notify (G_OBJECT (stream), "close-fd");
 293     }
 294 }
 295
 296 /**
 297  * g_unix_input_stream_get_close_fd:
 298  * @stream: a #GUnixInputStream
 299  *
 300  * Returns whether the file descriptor of @stream will be
 301  * closed when the stream is closed.
 302  *
 303  * Returns: %TRUE if the file descriptor is closed when done
 304  *
 305  * Since: 2.20
 306  */
 307 gboolean
 308 g_unix_input_stream_get_close_fd (GUnixInputStream *stream)
 309 {
 310   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), FALSE);
 311
 312   return stream->priv->close_fd;
 313 }
 314
 315 /**
 316  * g_unix_input_stream_get_fd:
 317  * @stream: a #GUnixInputStream
 318  *
 319  * Return the UNIX file descriptor that the stream reads from.
 320  *
 321  * Returns: The file descriptor of @stream
 322  *
 323  * Since: 2.20
 324  */
 325 gint
 326 g_unix_input_stream_get_fd (GUnixInputStream *stream)
 327 {
 328   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), -1);
 329
 330   return stream->priv->fd;
 331 }
 332
 333 static gssize
 334 g_unix_input_stream_read (GInputStream  *stream,
 335                           void          *buffer,
 336                           gsize          count,
 337                           GCancellable  *cancellable,
 338                           GError       **error)
 339 {
 340   GUnixInputStream *unix_stream;
 341   gssize res = -1;
 342   GPollFD poll_fds[2];
 343   int nfds;
 344   int poll_ret;
 345
 346   unix_stream = G_UNIX_INPUT_STREAM (stream);
 347
 348   poll_fds[0].fd = unix_stream->priv->fd;
 349   poll_fds[0].events = G_IO_IN;
 350   if (unix_stream->priv->is_pipe_or_socket &&
 351       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
 352     nfds = 2;
 353   else
 354     nfds = 1;
 355
 356   while (1)
 357     {
 358       poll_fds[0].revents = poll_fds[1].revents = 0;
 359       do
 360         poll_ret = g_poll (poll_fds, nfds, -1);
 361       while (poll_ret == -1 && errno == EINTR);
 362
 363       if (poll_ret == -1)
 364         {
 365           int errsv = errno;
 366
 367           g_set_error (error, G_IO_ERROR,
 368                        g_io_error_from_errno (errsv),
 369                        _("Error reading from file descriptor: %s"),
 370                        g_strerror (errsv));
 371           break;
 372         }
 373
 374       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 375         break;
 376
 377       if (!poll_fds[0].revents)
 378         continue;
 379
 380       res = read (unix_stream->priv->fd, buffer, count);
 381       if (res == -1)
 382         {
 383           int errsv = errno;
 384
 385           if (errsv == EINTR || errsv == EAGAIN)
 386             continue;
 387
 388           g_set_error (error, G_IO_ERROR,
 389                        g_io_error_from_errno (errsv),
 390                        _("Error reading from file descriptor: %s"),
 391                        g_strerror (errsv));
 392         }
 393
 394       break;
 395     }
 396
 397   if (nfds == 2)
 398     g_cancellable_release_fd (cancellable);
 399   return res;
 400 }
 401
 402 static gboolean
 403 g_unix_input_stream_close (GInputStream  *stream,
 404                            GCancellable  *cancellable,
 405                            GError       **error)
 406 {
 407   GUnixInputStream *unix_stream;
 408   int res;
 409
 410   unix_stream = G_UNIX_INPUT_STREAM (stream);
 411
 412   if (!unix_stream->priv->close_fd)
 413     return TRUE;
 414
 415   /* This might block during the close. Doesn't seem to be a way to avoid it though. */
 416   res = close (unix_stream->priv->fd);
 417   if (res == -1)
 418     {
 419       int errsv = errno;
 420
 421       g_set_error (error, G_IO_ERROR,
 422                    g_io_error_from_errno (errsv),
 423                    _("Error closing file descriptor: %s"),
 424                    g_strerror (errsv));
 425     }
 426
 427   return res != -1;
 428 }
 429
 430 static void
 431 g_unix_input_stream_skip_async (GInputStream        *stream,
 432                                 gsize                count,
 433                                 int                  io_priority,
 434                                 GCancellable        *cancellable,
 435                                 GAsyncReadyCallback  callback,
 436                                 gpointer             data)
 437 {
 438   g_warn_if_reached ();
 439   /* TODO: Not implemented */
 440 }
 441
 442 static gssize
 443 g_unix_input_stream_skip_finish  (GInputStream  *stream,
 444                                   GAsyncResult  *result,
 445                                   GError       **error)
 446 {
 447   g_warn_if_reached ();
 448   return 0;
 449   /* TODO: Not implemented */
 450 }
 451
 452 static void
 453 g_unix_input_stream_close_async (GInputStream        *stream,
 454                                  int                  io_priority,
 455                                  GCancellable        *cancellable,
 456                                  GAsyncReadyCallback  callback,
 457                                  gpointer             user_data)
 458 {
 459   GTask *task;
 460   GError *error = NULL;
 461
 462   task = g_task_new (stream, cancellable, callback, user_data);
 463   g_task_set_source_tag (task, g_unix_input_stream_close_async);
 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 }