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