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_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_finalize (GObject *object)
 113 {
 114   G_OBJECT_CLASS (g_unix_output_stream_parent_class)->finalize (object);
 115 }
 116
 117 static void
 118 g_unix_output_stream_class_init (GUnixOutputStreamClass *klass)
 119 {
 120   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 121   GOutputStreamClass *stream_class = G_OUTPUT_STREAM_CLASS (klass);
 122
 123   g_type_class_add_private (klass, sizeof (GUnixOutputStreamPrivate));
 124
 125   gobject_class->get_property = g_unix_output_stream_get_property;
 126   gobject_class->set_property = g_unix_output_stream_set_property;
 127   gobject_class->finalize = g_unix_output_stream_finalize;
 128
 129   stream_class->write_fn = g_unix_output_stream_write;
 130   stream_class->close_fn = g_unix_output_stream_close;
 131   stream_class->close_async = g_unix_output_stream_close_async;
 132   stream_class->close_finish = g_unix_output_stream_close_finish;
 133
 134    /**
 135    * GUnixOutputStream:fd:
 136    *
 137    * The file descriptor that the stream writes to.
 138    *
 139    * Since: 2.20
 140    */
 141   g_object_class_install_property (gobject_class,
 142                                    PROP_FD,
 143                                    g_param_spec_int ("fd",
 144                                                      P_("File descriptor"),
 145                                                      P_("The file descriptor to write to"),
 146                                                      G_MININT, G_MAXINT, -1,
 147                                                      G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 148
 149   /**
 150    * GUnixOutputStream:close-fd:
 151    *
 152    * Whether to close the file descriptor when the stream is closed.
 153    *
 154    * Since: 2.20
 155    */
 156   g_object_class_install_property (gobject_class,
 157                                    PROP_CLOSE_FD,
 158                                    g_param_spec_boolean ("close-fd",
 159                                                          P_("Close file descriptor"),
 160                                                          P_("Whether to close the file descriptor when the stream is closed"),
 161                                                          TRUE,
 162                                                          G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 163 }
 164
 165 static void
 166 g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface)
 167 {
 168   iface->is_writable = g_unix_output_stream_pollable_is_writable;
 169   iface->create_source = g_unix_output_stream_pollable_create_source;
 170 }
 171
 172 static void
 173 g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
 174 {
 175   iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_output_stream_get_fd;
 176 }
 177
 178 static void
 179 g_unix_output_stream_set_property (GObject         *object,
 180                                    guint            prop_id,
 181                                    const GValue    *value,
 182                                    GParamSpec      *pspec)
 183 {
 184   GUnixOutputStream *unix_stream;
 185
 186   unix_stream = G_UNIX_OUTPUT_STREAM (object);
 187
 188   switch (prop_id)
 189     {
 190     case PROP_FD:
 191       unix_stream->priv->fd = g_value_get_int (value);
 192       if (lseek (unix_stream->priv->fd, 0, SEEK_CUR) == -1 && errno == ESPIPE)
 193         unix_stream->priv->is_pipe_or_socket = TRUE;
 194       else
 195         unix_stream->priv->is_pipe_or_socket = FALSE;
 196       break;
 197     case PROP_CLOSE_FD:
 198       unix_stream->priv->close_fd = g_value_get_boolean (value);
 199       break;
 200     default:
 201       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 202       break;
 203     }
 204 }
 205
 206 static void
 207 g_unix_output_stream_get_property (GObject    *object,
 208                                    guint       prop_id,
 209                                    GValue     *value,
 210                                    GParamSpec *pspec)
 211 {
 212   GUnixOutputStream *unix_stream;
 213
 214   unix_stream = G_UNIX_OUTPUT_STREAM (object);
 215
 216   switch (prop_id)
 217     {
 218     case PROP_FD:
 219       g_value_set_int (value, unix_stream->priv->fd);
 220       break;
 221     case PROP_CLOSE_FD:
 222       g_value_set_boolean (value, unix_stream->priv->close_fd);
 223       break;
 224     default:
 225       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 226     }
 227 }
 228
 229 static void
 230 g_unix_output_stream_init (GUnixOutputStream *unix_stream)
 231 {
 232   unix_stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (unix_stream,
 233                                                    G_TYPE_UNIX_OUTPUT_STREAM,
 234                                                    GUnixOutputStreamPrivate);
 235
 236   unix_stream->priv->fd = -1;
 237   unix_stream->priv->close_fd = TRUE;
 238 }
 239
 240 /**
 241  * g_unix_output_stream_new:
 242  * @fd: a UNIX file descriptor
 243  * @close_fd: %TRUE to close the file descriptor when done
 244  *
 245  * Creates a new #GUnixOutputStream for the given @fd.
 246  *
 247  * If @close_fd, is %TRUE, the file descriptor will be closed when
 248  * the output stream is destroyed.
 249  *
 250  * Returns: a new #GOutputStream
 251  **/
 252 GOutputStream *
 253 g_unix_output_stream_new (gint     fd,
 254                           gboolean close_fd)
 255 {
 256   GUnixOutputStream *stream;
 257
 258   g_return_val_if_fail (fd != -1, NULL);
 259
 260   stream = g_object_new (G_TYPE_UNIX_OUTPUT_STREAM,
 261                          "fd", fd,
 262                          "close-fd", close_fd,
 263                          NULL);
 264
 265   return G_OUTPUT_STREAM (stream);
 266 }
 267
 268 /**
 269  * g_unix_output_stream_set_close_fd:
 270  * @stream: a #GUnixOutputStream
 271  * @close_fd: %TRUE to close the file descriptor when done
 272  *
 273  * Sets whether the file descriptor of @stream shall be closed
 274  * when the stream is closed.
 275  *
 276  * Since: 2.20
 277  */
 278 void
 279 g_unix_output_stream_set_close_fd (GUnixOutputStream *stream,
 280                                    gboolean           close_fd)
 281 {
 282   g_return_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream));
 283
 284   close_fd = close_fd != FALSE;
 285   if (stream->priv->close_fd != close_fd)
 286     {
 287       stream->priv->close_fd = close_fd;
 288       g_object_notify (G_OBJECT (stream), "close-fd");
 289     }
 290 }
 291
 292 /**
 293  * g_unix_output_stream_get_close_fd:
 294  * @stream: a #GUnixOutputStream
 295  *
 296  * Returns whether the file descriptor of @stream will be
 297  * closed when the stream is closed.
 298  *
 299  * Return value: %TRUE if the file descriptor is closed when done
 300  *
 301  * Since: 2.20
 302  */
 303 gboolean
 304 g_unix_output_stream_get_close_fd (GUnixOutputStream *stream)
 305 {
 306   g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), FALSE);
 307
 308   return stream->priv->close_fd;
 309 }
 310
 311 /**
 312  * g_unix_output_stream_get_fd:
 313  * @stream: a #GUnixOutputStream
 314  *
 315  * Return the UNIX file descriptor that the stream writes to.
 316  *
 317  * Return value: The file descriptor of @stream
 318  *
 319  * Since: 2.20
 320  */
 321 gint
 322 g_unix_output_stream_get_fd (GUnixOutputStream *stream)
 323 {
 324   g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), -1);
 325
 326   return stream->priv->fd;
 327 }
 328
 329 static gssize
 330 g_unix_output_stream_write (GOutputStream  *stream,
 331                             const void     *buffer,
 332                             gsize           count,
 333                             GCancellable   *cancellable,
 334                             GError        **error)
 335 {
 336   GUnixOutputStream *unix_stream;
 337   gssize res = -1;
 338   GPollFD poll_fds[2];
 339   int nfds;
 340   int poll_ret;
 341
 342   unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 343
 344   poll_fds[0].fd = unix_stream->priv->fd;
 345   poll_fds[0].events = G_IO_OUT;
 346
 347   if (unix_stream->priv->is_pipe_or_socket &&
 348       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
 349     nfds = 2;
 350   else
 351     nfds = 1;
 352
 353   while (1)
 354     {
 355       poll_fds[0].revents = poll_fds[1].revents = 0;
 356       do
 357         poll_ret = g_poll (poll_fds, nfds, -1);
 358       while (poll_ret == -1 && errno == EINTR);
 359
 360       if (poll_ret == -1)
 361         {
 362           int errsv = errno;
 363
 364           g_set_error (error, G_IO_ERROR,
 365                        g_io_error_from_errno (errsv),
 366                        _("Error writing to file descriptor: %s"),
 367                        g_strerror (errsv));
 368           break;
 369         }
 370
 371       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 372         break;
 373
 374       if (!poll_fds[0].revents)
 375         continue;
 376
 377       res = write (unix_stream->priv->fd, buffer, count);
 378       if (res == -1)
 379         {
 380           int errsv = errno;
 381
 382           if (errsv == EINTR || errsv == EAGAIN)
 383             continue;
 384
 385           g_set_error (error, G_IO_ERROR,
 386                        g_io_error_from_errno (errsv),
 387                        _("Error writing to file descriptor: %s"),
 388                        g_strerror (errsv));
 389         }
 390
 391       break;
 392     }
 393
 394   if (nfds == 2)
 395     g_cancellable_release_fd (cancellable);
 396   return res;
 397 }
 398
 399 static gboolean
 400 g_unix_output_stream_close (GOutputStream  *stream,
 401                             GCancellable   *cancellable,
 402                             GError        **error)
 403 {
 404   GUnixOutputStream *unix_stream;
 405   int res;
 406
 407   unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 408
 409   if (!unix_stream->priv->close_fd)
 410     return TRUE;
 411
 412   while (1)
 413     {
 414       /* This might block during the close. Doesn't seem to be a way to avoid it though. */
 415       res = close (unix_stream->priv->fd);
 416       if (res == -1)
 417         {
 418           int errsv = errno;
 419
 420           g_set_error (error, G_IO_ERROR,
 421                        g_io_error_from_errno (errsv),
 422                        _("Error closing file descriptor: %s"),
 423                        g_strerror (errsv));
 424         }
 425       break;
 426     }
 427
 428   return res != -1;
 429 }
 430
 431 typedef struct {
 432   GOutputStream *stream;
 433   GAsyncReadyCallback callback;
 434   gpointer user_data;
 435 } CloseAsyncData;
 436
 437 static gboolean
 438 close_async_cb (CloseAsyncData *data)
 439 {
 440   GUnixOutputStream *unix_stream;
 441   GSimpleAsyncResult *simple;
 442   GError *error = NULL;
 443   gboolean result;
 444   int res;
 445
 446   unix_stream = G_UNIX_OUTPUT_STREAM (data->stream);
 447
 448   if (!unix_stream->priv->close_fd)
 449     {
 450       result = TRUE;
 451       goto out;
 452     }
 453
 454   while (1)
 455     {
 456       res = close (unix_stream->priv->fd);
 457       if (res == -1)
 458         {
 459           int errsv = errno;
 460
 461           g_set_error (&error, G_IO_ERROR,
 462                        g_io_error_from_errno (errsv),
 463                        _("Error closing file descriptor: %s"),
 464                        g_strerror (errsv));
 465         }
 466       break;
 467     }
 468
 469   result = res != -1;
 470
 471  out:
 472   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 473                                       data->callback,
 474                                       data->user_data,
 475                                       g_unix_output_stream_close_async);
 476
 477   if (!result)
 478     g_simple_async_result_take_error (simple, error);
 479
 480   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 481   g_simple_async_result_complete (simple);
 482   g_object_unref (simple);
 483
 484   return FALSE;
 485 }
 486
 487 static void
 488 g_unix_output_stream_close_async (GOutputStream        *stream,
 489                                   int                  io_priority,
 490                                   GCancellable        *cancellable,
 491                                   GAsyncReadyCallback  callback,
 492                                   gpointer             user_data)
 493 {
 494   GSource *idle;
 495   CloseAsyncData *data;
 496
 497   data = g_new0 (CloseAsyncData, 1);
 498
 499   data->stream = stream;
 500   data->callback = callback;
 501   data->user_data = user_data;
 502
 503   idle = g_idle_source_new ();
 504   g_source_set_callback (idle, (GSourceFunc)close_async_cb, data, g_free);
 505   g_source_attach (idle, g_main_context_get_thread_default ());
 506   g_source_unref (idle);
 507 }
 508
 509 static gboolean
 510 g_unix_output_stream_close_finish (GOutputStream  *stream,
 511                                    GAsyncResult   *result,
 512                                    GError        **error)
 513 {
 514   /* Failures handled in generic close_finish code */
 515   return TRUE;
 516 }
 517
 518 static gboolean
 519 g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream)
 520 {
 521   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 522   GPollFD poll_fd;
 523   gint result;
 524
 525   poll_fd.fd = unix_stream->priv->fd;
 526   poll_fd.events = G_IO_OUT;
 527
 528   do
 529     result = g_poll (&poll_fd, 1, 0);
 530   while (result == -1 && errno == EINTR);
 531
 532   return poll_fd.revents != 0;
 533 }
 534
 535 static GSource *
 536 g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
 537                                              GCancellable          *cancellable)
 538 {
 539   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 540   GSource *inner_source, *pollable_source;
 541
 542   pollable_source = g_pollable_source_new (G_OBJECT (stream));
 543
 544   inner_source = _g_fd_source_new (unix_stream->priv->fd, G_IO_OUT, cancellable);
 545   g_source_set_dummy_callback (inner_source);
 546   g_source_add_child_source (pollable_source, inner_source);
 547   g_source_unref (inner_source);
 548
 549   return pollable_source;
 550 }