gio/gunixoutputstream.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 2.1 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 "gunixoutputstream.h"
  35 #include "gcancellable.h"
  36 #include "gasynchelper.h"
  37 #include "gfiledescriptorbased.h"
  38 #include "glibintl.h"
  39
  40
  41 /**
  42  * SECTION:gunixoutputstream
  43  * @short_description: Streaming output operations for UNIX file descriptors
  44  * @include: gio/gunixoutputstream.h
  45  * @see_also: #GOutputStream
  46  *
  47  * #GUnixOutputStream implements #GOutputStream for writing to 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/gunixoutputstream.h>` belongs to the UNIX-specific GIO
  54  * interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config file
  55  * when using it.
  56  */
  57
  58 enum {
  59   PROP_0,
  60   PROP_FD,
  61   PROP_CLOSE_FD
  62 };
  63
  64 struct _GUnixOutputStreamPrivate {
  65   int fd;
  66   guint close_fd : 1;
  67   guint is_pipe_or_socket : 1;
  68 };
  69
  70 static void g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface);
  71 static void g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);
  72
  73 G_DEFINE_TYPE_WITH_CODE (GUnixOutputStream, g_unix_output_stream, G_TYPE_OUTPUT_STREAM,
  74                          G_ADD_PRIVATE (GUnixOutputStream)
  75                          G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_OUTPUT_STREAM,
  76                                                 g_unix_output_stream_pollable_iface_init)
  77                          G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
  78                                                 g_unix_output_stream_file_descriptor_based_iface_init)
  79                          )
  80
  81 static void     g_unix_output_stream_set_property (GObject              *object,
  82                                                    guint                 prop_id,
  83                                                    const GValue         *value,
  84                                                    GParamSpec           *pspec);
  85 static void     g_unix_output_stream_get_property (GObject              *object,
  86                                                    guint                 prop_id,
  87                                                    GValue               *value,
  88                                                    GParamSpec           *pspec);
  89 static gssize   g_unix_output_stream_write        (GOutputStream        *stream,
  90                                                    const void           *buffer,
  91                                                    gsize                 count,
  92                                                    GCancellable         *cancellable,
  93                                                    GError              **error);
  94 static gboolean g_unix_output_stream_close        (GOutputStream        *stream,
  95                                                    GCancellable         *cancellable,
  96                                                    GError              **error);
  97 static void     g_unix_output_stream_close_async  (GOutputStream        *stream,
  98                                                    int                   io_priority,
  99                                                    GCancellable         *cancellable,
 100                                                    GAsyncReadyCallback   callback,
 101                                                    gpointer              data);
 102 static gboolean g_unix_output_stream_close_finish (GOutputStream        *stream,
 103                                                    GAsyncResult         *result,
 104                                                    GError              **error);
 105
 106 static gboolean g_unix_output_stream_pollable_can_poll      (GPollableOutputStream *stream);
 107 static gboolean g_unix_output_stream_pollable_is_writable   (GPollableOutputStream *stream);
 108 static GSource *g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
 109                                                              GCancellable         *cancellable);
 110
 111 static void
 112 g_unix_output_stream_class_init (GUnixOutputStreamClass *klass)
 113 {
 114   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 115   GOutputStreamClass *stream_class = G_OUTPUT_STREAM_CLASS (klass);
 116
 117   gobject_class->get_property = g_unix_output_stream_get_property;
 118   gobject_class->set_property = g_unix_output_stream_set_property;
 119
 120   stream_class->write_fn = g_unix_output_stream_write;
 121   stream_class->close_fn = g_unix_output_stream_close;
 122   stream_class->close_async = g_unix_output_stream_close_async;
 123   stream_class->close_finish = g_unix_output_stream_close_finish;
 124
 125    /**
 126    * GUnixOutputStream:fd:
 127    *
 128    * The file descriptor that the stream writes to.
 129    *
 130    * Since: 2.20
 131    */
 132   g_object_class_install_property (gobject_class,
 133                                    PROP_FD,
 134                                    g_param_spec_int ("fd",
 135                                                      P_("File descriptor"),
 136                                                      P_("The file descriptor to write to"),
 137                                                      G_MININT, G_MAXINT, -1,
 138                                                      G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 139
 140   /**
 141    * GUnixOutputStream:close-fd:
 142    *
 143    * Whether to close the file descriptor when the stream is closed.
 144    *
 145    * Since: 2.20
 146    */
 147   g_object_class_install_property (gobject_class,
 148                                    PROP_CLOSE_FD,
 149                                    g_param_spec_boolean ("close-fd",
 150                                                          P_("Close file descriptor"),
 151                                                          P_("Whether to close the file descriptor when the stream is closed"),
 152                                                          TRUE,
 153                                                          G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 154 }
 155
 156 static void
 157 g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface)
 158 {
 159   iface->can_poll = g_unix_output_stream_pollable_can_poll;
 160   iface->is_writable = g_unix_output_stream_pollable_is_writable;
 161   iface->create_source = g_unix_output_stream_pollable_create_source;
 162 }
 163
 164 static void
 165 g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
 166 {
 167   iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_output_stream_get_fd;
 168 }
 169
 170 static void
 171 g_unix_output_stream_set_property (GObject         *object,
 172                                    guint            prop_id,
 173                                    const GValue    *value,
 174                                    GParamSpec      *pspec)
 175 {
 176   GUnixOutputStream *unix_stream;
 177
 178   unix_stream = G_UNIX_OUTPUT_STREAM (object);
 179
 180   switch (prop_id)
 181     {
 182     case PROP_FD:
 183       unix_stream->priv->fd = g_value_get_int (value);
 184       if (lseek (unix_stream->priv->fd, 0, SEEK_CUR) == -1 && errno == ESPIPE)
 185         unix_stream->priv->is_pipe_or_socket = TRUE;
 186       else
 187         unix_stream->priv->is_pipe_or_socket = FALSE;
 188       break;
 189     case PROP_CLOSE_FD:
 190       unix_stream->priv->close_fd = g_value_get_boolean (value);
 191       break;
 192     default:
 193       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 194       break;
 195     }
 196 }
 197
 198 static void
 199 g_unix_output_stream_get_property (GObject    *object,
 200                                    guint       prop_id,
 201                                    GValue     *value,
 202                                    GParamSpec *pspec)
 203 {
 204   GUnixOutputStream *unix_stream;
 205
 206   unix_stream = G_UNIX_OUTPUT_STREAM (object);
 207
 208   switch (prop_id)
 209     {
 210     case PROP_FD:
 211       g_value_set_int (value, unix_stream->priv->fd);
 212       break;
 213     case PROP_CLOSE_FD:
 214       g_value_set_boolean (value, unix_stream->priv->close_fd);
 215       break;
 216     default:
 217       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 218     }
 219 }
 220
 221 static void
 222 g_unix_output_stream_init (GUnixOutputStream *unix_stream)
 223 {
 224   unix_stream->priv = g_unix_output_stream_get_instance_private (unix_stream);
 225   unix_stream->priv->fd = -1;
 226   unix_stream->priv->close_fd = TRUE;
 227 }
 228
 229 /**
 230  * g_unix_output_stream_new:
 231  * @fd: a UNIX file descriptor
 232  * @close_fd: %TRUE to close the file descriptor when done
 233  *
 234  * Creates a new #GUnixOutputStream for the given @fd.
 235  *
 236  * If @close_fd, is %TRUE, the file descriptor will be closed when
 237  * the output stream is destroyed.
 238  *
 239  * Returns: a new #GOutputStream
 240  **/
 241 GOutputStream *
 242 g_unix_output_stream_new (gint     fd,
 243                           gboolean close_fd)
 244 {
 245   GUnixOutputStream *stream;
 246
 247   g_return_val_if_fail (fd != -1, NULL);
 248
 249   stream = g_object_new (G_TYPE_UNIX_OUTPUT_STREAM,
 250                          "fd", fd,
 251                          "close-fd", close_fd,
 252                          NULL);
 253
 254   return G_OUTPUT_STREAM (stream);
 255 }
 256
 257 /**
 258  * g_unix_output_stream_set_close_fd:
 259  * @stream: a #GUnixOutputStream
 260  * @close_fd: %TRUE to close the file descriptor when done
 261  *
 262  * Sets whether the file descriptor of @stream shall be closed
 263  * when the stream is closed.
 264  *
 265  * Since: 2.20
 266  */
 267 void
 268 g_unix_output_stream_set_close_fd (GUnixOutputStream *stream,
 269                                    gboolean           close_fd)
 270 {
 271   g_return_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream));
 272
 273   close_fd = close_fd != FALSE;
 274   if (stream->priv->close_fd != close_fd)
 275     {
 276       stream->priv->close_fd = close_fd;
 277       g_object_notify (G_OBJECT (stream), "close-fd");
 278     }
 279 }
 280
 281 /**
 282  * g_unix_output_stream_get_close_fd:
 283  * @stream: a #GUnixOutputStream
 284  *
 285  * Returns whether the file descriptor of @stream will be
 286  * closed when the stream is closed.
 287  *
 288  * Returns: %TRUE if the file descriptor is closed when done
 289  *
 290  * Since: 2.20
 291  */
 292 gboolean
 293 g_unix_output_stream_get_close_fd (GUnixOutputStream *stream)
 294 {
 295   g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), FALSE);
 296
 297   return stream->priv->close_fd;
 298 }
 299
 300 /**
 301  * g_unix_output_stream_get_fd:
 302  * @stream: a #GUnixOutputStream
 303  *
 304  * Return the UNIX file descriptor that the stream writes to.
 305  *
 306  * Returns: The file descriptor of @stream
 307  *
 308  * Since: 2.20
 309  */
 310 gint
 311 g_unix_output_stream_get_fd (GUnixOutputStream *stream)
 312 {
 313   g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), -1);
 314
 315   return stream->priv->fd;
 316 }
 317
 318 static gssize
 319 g_unix_output_stream_write (GOutputStream  *stream,
 320                             const void     *buffer,
 321                             gsize           count,
 322                             GCancellable   *cancellable,
 323                             GError        **error)
 324 {
 325   GUnixOutputStream *unix_stream;
 326   gssize res = -1;
 327   GPollFD poll_fds[2];
 328   int nfds;
 329   int poll_ret;
 330
 331   unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 332
 333   poll_fds[0].fd = unix_stream->priv->fd;
 334   poll_fds[0].events = G_IO_OUT;
 335
 336   if (unix_stream->priv->is_pipe_or_socket &&
 337       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
 338     nfds = 2;
 339   else
 340     nfds = 1;
 341
 342   while (1)
 343     {
 344       int errsv;
 345
 346       poll_fds[0].revents = poll_fds[1].revents = 0;
 347       do
 348         {
 349           poll_ret = g_poll (poll_fds, nfds, -1);
 350           errsv = errno;
 351         }
 352       while (poll_ret == -1 && errsv == EINTR);
 353
 354       if (poll_ret == -1)
 355         {
 356           g_set_error (error, G_IO_ERROR,
 357                        g_io_error_from_errno (errsv),
 358                        _("Error writing to file descriptor: %s"),
 359                        g_strerror (errsv));
 360           break;
 361         }
 362
 363       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 364         break;
 365
 366       if (!poll_fds[0].revents)
 367         continue;
 368
 369       res = write (unix_stream->priv->fd, buffer, count);
 370       errsv = errno;
 371       if (res == -1)
 372         {
 373           if (errsv == EINTR || errsv == EAGAIN)
 374             continue;
 375
 376           g_set_error (error, G_IO_ERROR,
 377                        g_io_error_from_errno (errsv),
 378                        _("Error writing to file descriptor: %s"),
 379                        g_strerror (errsv));
 380         }
 381
 382       break;
 383     }
 384
 385   if (nfds == 2)
 386     g_cancellable_release_fd (cancellable);
 387   return res;
 388 }
 389
 390 static gboolean
 391 g_unix_output_stream_close (GOutputStream  *stream,
 392                             GCancellable   *cancellable,
 393                             GError        **error)
 394 {
 395   GUnixOutputStream *unix_stream;
 396   int res;
 397
 398   unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 399
 400   if (!unix_stream->priv->close_fd)
 401     return TRUE;
 402
 403   /* This might block during the close. Doesn't seem to be a way to avoid it though. */
 404   res = close (unix_stream->priv->fd);
 405   if (res == -1)
 406     {
 407       int errsv = errno;
 408
 409       g_set_error (error, G_IO_ERROR,
 410                    g_io_error_from_errno (errsv),
 411                    _("Error closing file descriptor: %s"),
 412                    g_strerror (errsv));
 413     }
 414
 415   return res != -1;
 416 }
 417
 418 static void
 419 g_unix_output_stream_close_async (GOutputStream       *stream,
 420                                   int                  io_priority,
 421                                   GCancellable        *cancellable,
 422                                   GAsyncReadyCallback  callback,
 423                                   gpointer             user_data)
 424 {
 425   GTask *task;
 426   GError *error = NULL;
 427
 428   task = g_task_new (stream, cancellable, callback, user_data);
 429   g_task_set_source_tag (task, g_unix_output_stream_close_async);
 430   g_task_set_priority (task, io_priority);
 431
 432   if (g_unix_output_stream_close (stream, cancellable, &error))
 433     g_task_return_boolean (task, TRUE);
 434   else
 435     g_task_return_error (task, error);
 436   g_object_unref (task);
 437 }
 438
 439 static gboolean
 440 g_unix_output_stream_close_finish (GOutputStream  *stream,
 441                                    GAsyncResult   *result,
 442                                    GError        **error)
 443 {
 444   g_return_val_if_fail (g_task_is_valid (result, stream), FALSE);
 445
 446   return g_task_propagate_boolean (G_TASK (result), error);
 447 }
 448
 449 static gboolean
 450 g_unix_output_stream_pollable_can_poll (GPollableOutputStream *stream)
 451 {
 452   return G_UNIX_OUTPUT_STREAM (stream)->priv->is_pipe_or_socket;
 453 }
 454
 455 static gboolean
 456 g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream)
 457 {
 458   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 459   GPollFD poll_fd;
 460   gint result;
 461
 462   poll_fd.fd = unix_stream->priv->fd;
 463   poll_fd.events = G_IO_OUT;
 464   poll_fd.revents = 0;
 465
 466   do
 467     result = g_poll (&poll_fd, 1, 0);
 468   while (result == -1 && errno == EINTR);
 469
 470   return poll_fd.revents != 0;
 471 }
 472
 473 static GSource *
 474 g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
 475                                              GCancellable          *cancellable)
 476 {
 477   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 478   GSource *inner_source, *cancellable_source, *pollable_source;
 479
 480   pollable_source = g_pollable_source_new (G_OBJECT (stream));
 481
 482   inner_source = g_unix_fd_source_new (unix_stream->priv->fd, G_IO_OUT);
 483   g_source_set_dummy_callback (inner_source);
 484   g_source_add_child_source (pollable_source, inner_source);
 485   g_source_unref (inner_source);
 486
 487   if (cancellable)
 488     {
 489       cancellable_source = g_cancellable_source_new (cancellable);
 490       g_source_set_dummy_callback (cancellable_source);
 491       g_source_add_child_source (pollable_source, cancellable_source);
 492       g_source_unref (cancellable_source);
 493     }
 494
 495   return pollable_source;
 496 }