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