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 static void g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface);
  67 static void g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);
  68
  69 G_DEFINE_TYPE_WITH_CODE (GUnixOutputStream, g_unix_output_stream, G_TYPE_OUTPUT_STREAM,
  70                          G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_OUTPUT_STREAM,
  71                                                 g_unix_output_stream_pollable_iface_init)
  72                          G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
  73                                                 g_unix_output_stream_file_descriptor_based_iface_init)
  74                          )
  75
  76 struct _GUnixOutputStreamPrivate {
  77   int fd;
  78   guint close_fd : 1;
  79   guint is_pipe_or_socket : 1;
  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_finalize (GObject *object)
 114 {
 115   G_OBJECT_CLASS (g_unix_output_stream_parent_class)->finalize (object);
 116 }
 117
 118 static void
 119 g_unix_output_stream_class_init (GUnixOutputStreamClass *klass)
 120 {
 121   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 122   GOutputStreamClass *stream_class = G_OUTPUT_STREAM_CLASS (klass);
 123
 124   g_type_class_add_private (klass, sizeof (GUnixOutputStreamPrivate));
 125
 126   gobject_class->get_property = g_unix_output_stream_get_property;
 127   gobject_class->set_property = g_unix_output_stream_set_property;
 128   gobject_class->finalize = g_unix_output_stream_finalize;
 129
 130   stream_class->write_fn = g_unix_output_stream_write;
 131   stream_class->close_fn = g_unix_output_stream_close;
 132   stream_class->close_async = g_unix_output_stream_close_async;
 133   stream_class->close_finish = g_unix_output_stream_close_finish;
 134
 135    /**
 136    * GUnixOutputStream:fd:
 137    *
 138    * The file descriptor that the stream writes to.
 139    *
 140    * Since: 2.20
 141    */
 142   g_object_class_install_property (gobject_class,
 143                                    PROP_FD,
 144                                    g_param_spec_int ("fd",
 145                                                      P_("File descriptor"),
 146                                                      P_("The file descriptor to write to"),
 147                                                      G_MININT, G_MAXINT, -1,
 148                                                      G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 149
 150   /**
 151    * GUnixOutputStream:close-fd:
 152    *
 153    * Whether to close the file descriptor when the stream is closed.
 154    *
 155    * Since: 2.20
 156    */
 157   g_object_class_install_property (gobject_class,
 158                                    PROP_CLOSE_FD,
 159                                    g_param_spec_boolean ("close-fd",
 160                                                          P_("Close file descriptor"),
 161                                                          P_("Whether to close the file descriptor when the stream is closed"),
 162                                                          TRUE,
 163                                                          G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 164 }
 165
 166 static void
 167 g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface)
 168 {
 169   iface->can_poll = g_unix_output_stream_pollable_can_poll;
 170   iface->is_writable = g_unix_output_stream_pollable_is_writable;
 171   iface->create_source = g_unix_output_stream_pollable_create_source;
 172 }
 173
 174 static void
 175 g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
 176 {
 177   iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_output_stream_get_fd;
 178 }
 179
 180 static void
 181 g_unix_output_stream_set_property (GObject         *object,
 182                                    guint            prop_id,
 183                                    const GValue    *value,
 184                                    GParamSpec      *pspec)
 185 {
 186   GUnixOutputStream *unix_stream;
 187
 188   unix_stream = G_UNIX_OUTPUT_STREAM (object);
 189
 190   switch (prop_id)
 191     {
 192     case PROP_FD:
 193       unix_stream->priv->fd = g_value_get_int (value);
 194       if (lseek (unix_stream->priv->fd, 0, SEEK_CUR) == -1 && errno == ESPIPE)
 195         unix_stream->priv->is_pipe_or_socket = TRUE;
 196       else
 197         unix_stream->priv->is_pipe_or_socket = FALSE;
 198       break;
 199     case PROP_CLOSE_FD:
 200       unix_stream->priv->close_fd = g_value_get_boolean (value);
 201       break;
 202     default:
 203       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 204       break;
 205     }
 206 }
 207
 208 static void
 209 g_unix_output_stream_get_property (GObject    *object,
 210                                    guint       prop_id,
 211                                    GValue     *value,
 212                                    GParamSpec *pspec)
 213 {
 214   GUnixOutputStream *unix_stream;
 215
 216   unix_stream = G_UNIX_OUTPUT_STREAM (object);
 217
 218   switch (prop_id)
 219     {
 220     case PROP_FD:
 221       g_value_set_int (value, unix_stream->priv->fd);
 222       break;
 223     case PROP_CLOSE_FD:
 224       g_value_set_boolean (value, unix_stream->priv->close_fd);
 225       break;
 226     default:
 227       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 228     }
 229 }
 230
 231 static void
 232 g_unix_output_stream_init (GUnixOutputStream *unix_stream)
 233 {
 234   unix_stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (unix_stream,
 235                                                    G_TYPE_UNIX_OUTPUT_STREAM,
 236                                                    GUnixOutputStreamPrivate);
 237
 238   unix_stream->priv->fd = -1;
 239   unix_stream->priv->close_fd = TRUE;
 240 }
 241
 242 /**
 243  * g_unix_output_stream_new:
 244  * @fd: a UNIX file descriptor
 245  * @close_fd: %TRUE to close the file descriptor when done
 246  *
 247  * Creates a new #GUnixOutputStream for the given @fd.
 248  *
 249  * If @close_fd, is %TRUE, the file descriptor will be closed when
 250  * the output stream is destroyed.
 251  *
 252  * Returns: a new #GOutputStream
 253  **/
 254 GOutputStream *
 255 g_unix_output_stream_new (gint     fd,
 256                           gboolean close_fd)
 257 {
 258   GUnixOutputStream *stream;
 259
 260   g_return_val_if_fail (fd != -1, NULL);
 261
 262   stream = g_object_new (G_TYPE_UNIX_OUTPUT_STREAM,
 263                          "fd", fd,
 264                          "close-fd", close_fd,
 265                          NULL);
 266
 267   return G_OUTPUT_STREAM (stream);
 268 }
 269
 270 /**
 271  * g_unix_output_stream_set_close_fd:
 272  * @stream: a #GUnixOutputStream
 273  * @close_fd: %TRUE to close the file descriptor when done
 274  *
 275  * Sets whether the file descriptor of @stream shall be closed
 276  * when the stream is closed.
 277  *
 278  * Since: 2.20
 279  */
 280 void
 281 g_unix_output_stream_set_close_fd (GUnixOutputStream *stream,
 282                                    gboolean           close_fd)
 283 {
 284   g_return_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream));
 285
 286   close_fd = close_fd != FALSE;
 287   if (stream->priv->close_fd != close_fd)
 288     {
 289       stream->priv->close_fd = close_fd;
 290       g_object_notify (G_OBJECT (stream), "close-fd");
 291     }
 292 }
 293
 294 /**
 295  * g_unix_output_stream_get_close_fd:
 296  * @stream: a #GUnixOutputStream
 297  *
 298  * Returns whether the file descriptor of @stream will be
 299  * closed when the stream is closed.
 300  *
 301  * Return value: %TRUE if the file descriptor is closed when done
 302  *
 303  * Since: 2.20
 304  */
 305 gboolean
 306 g_unix_output_stream_get_close_fd (GUnixOutputStream *stream)
 307 {
 308   g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), FALSE);
 309
 310   return stream->priv->close_fd;
 311 }
 312
 313 /**
 314  * g_unix_output_stream_get_fd:
 315  * @stream: a #GUnixOutputStream
 316  *
 317  * Return the UNIX file descriptor that the stream writes to.
 318  *
 319  * Return value: The file descriptor of @stream
 320  *
 321  * Since: 2.20
 322  */
 323 gint
 324 g_unix_output_stream_get_fd (GUnixOutputStream *stream)
 325 {
 326   g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), -1);
 327
 328   return stream->priv->fd;
 329 }
 330
 331 static gssize
 332 g_unix_output_stream_write (GOutputStream  *stream,
 333                             const void     *buffer,
 334                             gsize           count,
 335                             GCancellable   *cancellable,
 336                             GError        **error)
 337 {
 338   GUnixOutputStream *unix_stream;
 339   gssize res = -1;
 340   GPollFD poll_fds[2];
 341   int nfds;
 342   int poll_ret;
 343
 344   unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 345
 346   poll_fds[0].fd = unix_stream->priv->fd;
 347   poll_fds[0].events = G_IO_OUT;
 348
 349   if (unix_stream->priv->is_pipe_or_socket &&
 350       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
 351     nfds = 2;
 352   else
 353     nfds = 1;
 354
 355   while (1)
 356     {
 357       poll_fds[0].revents = poll_fds[1].revents = 0;
 358       do
 359         poll_ret = g_poll (poll_fds, nfds, -1);
 360       while (poll_ret == -1 && errno == EINTR);
 361
 362       if (poll_ret == -1)
 363         {
 364           int errsv = errno;
 365
 366           g_set_error (error, G_IO_ERROR,
 367                        g_io_error_from_errno (errsv),
 368                        _("Error writing to file descriptor: %s"),
 369                        g_strerror (errsv));
 370           break;
 371         }
 372
 373       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 374         break;
 375
 376       if (!poll_fds[0].revents)
 377         continue;
 378
 379       res = write (unix_stream->priv->fd, buffer, count);
 380       if (res == -1)
 381         {
 382           int errsv = errno;
 383
 384           if (errsv == EINTR || errsv == EAGAIN)
 385             continue;
 386
 387           g_set_error (error, G_IO_ERROR,
 388                        g_io_error_from_errno (errsv),
 389                        _("Error writing to file descriptor: %s"),
 390                        g_strerror (errsv));
 391         }
 392
 393       break;
 394     }
 395
 396   if (nfds == 2)
 397     g_cancellable_release_fd (cancellable);
 398   return res;
 399 }
 400
 401 static gboolean
 402 g_unix_output_stream_close (GOutputStream  *stream,
 403                             GCancellable   *cancellable,
 404                             GError        **error)
 405 {
 406   GUnixOutputStream *unix_stream;
 407   int res;
 408
 409   unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 410
 411   if (!unix_stream->priv->close_fd)
 412     return TRUE;
 413
 414   while (1)
 415     {
 416       /* This might block during the close. Doesn't seem to be a way to avoid it though. */
 417       res = close (unix_stream->priv->fd);
 418       if (res == -1)
 419         {
 420           int errsv = errno;
 421
 422           g_set_error (error, G_IO_ERROR,
 423                        g_io_error_from_errno (errsv),
 424                        _("Error closing file descriptor: %s"),
 425                        g_strerror (errsv));
 426         }
 427       break;
 428     }
 429
 430   return res != -1;
 431 }
 432
 433 typedef struct {
 434   GOutputStream *stream;
 435   GAsyncReadyCallback callback;
 436   gpointer user_data;
 437 } CloseAsyncData;
 438
 439 static gboolean
 440 close_async_cb (CloseAsyncData *data)
 441 {
 442   GUnixOutputStream *unix_stream;
 443   GSimpleAsyncResult *simple;
 444   GError *error = NULL;
 445   gboolean result;
 446   int res;
 447
 448   unix_stream = G_UNIX_OUTPUT_STREAM (data->stream);
 449
 450   if (!unix_stream->priv->close_fd)
 451     {
 452       result = TRUE;
 453       goto out;
 454     }
 455
 456   while (1)
 457     {
 458       res = close (unix_stream->priv->fd);
 459       if (res == -1)
 460         {
 461           int errsv = errno;
 462
 463           g_set_error (&error, G_IO_ERROR,
 464                        g_io_error_from_errno (errsv),
 465                        _("Error closing file descriptor: %s"),
 466                        g_strerror (errsv));
 467         }
 468       break;
 469     }
 470
 471   result = res != -1;
 472
 473  out:
 474   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 475                                       data->callback,
 476                                       data->user_data,
 477                                       g_unix_output_stream_close_async);
 478
 479   if (!result)
 480     g_simple_async_result_take_error (simple, error);
 481
 482   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 483   g_simple_async_result_complete (simple);
 484   g_object_unref (simple);
 485
 486   return FALSE;
 487 }
 488
 489 static void
 490 g_unix_output_stream_close_async (GOutputStream        *stream,
 491                                   int                  io_priority,
 492                                   GCancellable        *cancellable,
 493                                   GAsyncReadyCallback  callback,
 494                                   gpointer             user_data)
 495 {
 496   GSource *idle;
 497   CloseAsyncData *data;
 498
 499   data = g_new0 (CloseAsyncData, 1);
 500
 501   data->stream = stream;
 502   data->callback = callback;
 503   data->user_data = user_data;
 504
 505   idle = g_idle_source_new ();
 506   g_source_set_callback (idle, (GSourceFunc)close_async_cb, data, g_free);
 507   g_source_attach (idle, g_main_context_get_thread_default ());
 508   g_source_unref (idle);
 509 }
 510
 511 static gboolean
 512 g_unix_output_stream_close_finish (GOutputStream  *stream,
 513                                    GAsyncResult   *result,
 514                                    GError        **error)
 515 {
 516   /* Failures handled in generic close_finish code */
 517   return TRUE;
 518 }
 519
 520 static gboolean
 521 g_unix_output_stream_pollable_can_poll (GPollableOutputStream *stream)
 522 {
 523   return G_UNIX_OUTPUT_STREAM (stream)->priv->is_pipe_or_socket;
 524 }
 525
 526 static gboolean
 527 g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream)
 528 {
 529   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 530   GPollFD poll_fd;
 531   gint result;
 532
 533   poll_fd.fd = unix_stream->priv->fd;
 534   poll_fd.events = G_IO_OUT;
 535
 536   do
 537     result = g_poll (&poll_fd, 1, 0);
 538   while (result == -1 && errno == EINTR);
 539
 540   return poll_fd.revents != 0;
 541 }
 542
 543 static GSource *
 544 g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
 545                                              GCancellable          *cancellable)
 546 {
 547   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 548   GSource *inner_source, *pollable_source;
 549
 550   pollable_source = g_pollable_source_new (G_OBJECT (stream));
 551
 552   inner_source = _g_fd_source_new (unix_stream->priv->fd, G_IO_OUT, cancellable);
 553   g_source_set_dummy_callback (inner_source);
 554   g_source_add_child_source (pollable_source, inner_source);
 555   g_source_unref (inner_source);
 556
 557   return pollable_source;
 558 }