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