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 like
  54  * #GLocalFileOutputStream.)
  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 static void g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface);
  68 static void g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);
  69
  70 G_DEFINE_TYPE_WITH_CODE (GUnixOutputStream, g_unix_output_stream, G_TYPE_OUTPUT_STREAM,
  71                          G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_OUTPUT_STREAM,
  72                                                 g_unix_output_stream_pollable_iface_init)
  73                          G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
  74                                                 g_unix_output_stream_file_descriptor_based_iface_init)
  75                          )
  76
  77 struct _GUnixOutputStreamPrivate {
  78   int fd;
  79   guint close_fd : 1;
  80   guint is_pipe_or_socket : 1;
  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_write_async  (GOutputStream        *stream,
 100                                                    const void           *buffer,
 101                                                    gsize                 count,
 102                                                    int                   io_priority,
 103                                                    GCancellable         *cancellable,
 104                                                    GAsyncReadyCallback   callback,
 105                                                    gpointer              data);
 106 static gssize   g_unix_output_stream_write_finish (GOutputStream        *stream,
 107                                                    GAsyncResult         *result,
 108                                                    GError              **error);
 109 static void     g_unix_output_stream_close_async  (GOutputStream        *stream,
 110                                                    int                   io_priority,
 111                                                    GCancellable         *cancellable,
 112                                                    GAsyncReadyCallback   callback,
 113                                                    gpointer              data);
 114 static gboolean g_unix_output_stream_close_finish (GOutputStream        *stream,
 115                                                    GAsyncResult         *result,
 116                                                    GError              **error);
 117
 118 static gboolean g_unix_output_stream_pollable_is_writable   (GPollableOutputStream *stream);
 119 static GSource *g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
 120                                                              GCancellable         *cancellable);
 121
 122 static void
 123 g_unix_output_stream_finalize (GObject *object)
 124 {
 125   G_OBJECT_CLASS (g_unix_output_stream_parent_class)->finalize (object);
 126 }
 127
 128 static void
 129 g_unix_output_stream_class_init (GUnixOutputStreamClass *klass)
 130 {
 131   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 132   GOutputStreamClass *stream_class = G_OUTPUT_STREAM_CLASS (klass);
 133
 134   g_type_class_add_private (klass, sizeof (GUnixOutputStreamPrivate));
 135
 136   gobject_class->get_property = g_unix_output_stream_get_property;
 137   gobject_class->set_property = g_unix_output_stream_set_property;
 138   gobject_class->finalize = g_unix_output_stream_finalize;
 139
 140   stream_class->write_fn = g_unix_output_stream_write;
 141   stream_class->close_fn = g_unix_output_stream_close;
 142   stream_class->write_async = g_unix_output_stream_write_async;
 143   stream_class->write_finish = g_unix_output_stream_write_finish;
 144   stream_class->close_async = g_unix_output_stream_close_async;
 145   stream_class->close_finish = g_unix_output_stream_close_finish;
 146
 147    /**
 148    * GUnixOutputStream:fd:
 149    *
 150    * The file descriptor that the stream writes to.
 151    *
 152    * Since: 2.20
 153    */
 154   g_object_class_install_property (gobject_class,
 155                                    PROP_FD,
 156                                    g_param_spec_int ("fd",
 157                                                      P_("File descriptor"),
 158                                                      P_("The file descriptor to write to"),
 159                                                      G_MININT, G_MAXINT, -1,
 160                                                      G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 161
 162   /**
 163    * GUnixOutputStream:close-fd:
 164    *
 165    * Whether to close the file descriptor when the stream is closed.
 166    *
 167    * Since: 2.20
 168    */
 169   g_object_class_install_property (gobject_class,
 170                                    PROP_CLOSE_FD,
 171                                    g_param_spec_boolean ("close-fd",
 172                                                          P_("Close file descriptor"),
 173                                                          P_("Whether to close the file descriptor when the stream is closed"),
 174                                                          TRUE,
 175                                                          G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 176 }
 177
 178 static void
 179 g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface)
 180 {
 181   iface->is_writable = g_unix_output_stream_pollable_is_writable;
 182   iface->create_source = g_unix_output_stream_pollable_create_source;
 183 }
 184
 185 static void
 186 g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
 187 {
 188   iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_output_stream_get_fd;
 189 }
 190
 191 static void
 192 g_unix_output_stream_set_property (GObject         *object,
 193                                    guint            prop_id,
 194                                    const GValue    *value,
 195                                    GParamSpec      *pspec)
 196 {
 197   GUnixOutputStream *unix_stream;
 198
 199   unix_stream = G_UNIX_OUTPUT_STREAM (object);
 200
 201   switch (prop_id)
 202     {
 203     case PROP_FD:
 204       unix_stream->priv->fd = g_value_get_int (value);
 205       if (lseek (unix_stream->priv->fd, 0, SEEK_CUR) == -1 && errno == ESPIPE)
 206         unix_stream->priv->is_pipe_or_socket = TRUE;
 207       else
 208         unix_stream->priv->is_pipe_or_socket = FALSE;
 209       break;
 210     case PROP_CLOSE_FD:
 211       unix_stream->priv->close_fd = g_value_get_boolean (value);
 212       break;
 213     default:
 214       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 215       break;
 216     }
 217 }
 218
 219 static void
 220 g_unix_output_stream_get_property (GObject    *object,
 221                                    guint       prop_id,
 222                                    GValue     *value,
 223                                    GParamSpec *pspec)
 224 {
 225   GUnixOutputStream *unix_stream;
 226
 227   unix_stream = G_UNIX_OUTPUT_STREAM (object);
 228
 229   switch (prop_id)
 230     {
 231     case PROP_FD:
 232       g_value_set_int (value, unix_stream->priv->fd);
 233       break;
 234     case PROP_CLOSE_FD:
 235       g_value_set_boolean (value, unix_stream->priv->close_fd);
 236       break;
 237     default:
 238       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 239     }
 240 }
 241
 242 static void
 243 g_unix_output_stream_init (GUnixOutputStream *unix_stream)
 244 {
 245   unix_stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (unix_stream,
 246                                                    G_TYPE_UNIX_OUTPUT_STREAM,
 247                                                    GUnixOutputStreamPrivate);
 248
 249   unix_stream->priv->fd = -1;
 250   unix_stream->priv->close_fd = TRUE;
 251 }
 252
 253 /**
 254  * g_unix_output_stream_new:
 255  * @fd: a UNIX file descriptor
 256  * @close_fd: %TRUE to close the file descriptor when done
 257  *
 258  * Creates a new #GUnixOutputStream for the given @fd.
 259  *
 260  * If @close_fd, is %TRUE, the file descriptor will be closed when
 261  * the output stream is destroyed.
 262  *
 263  * Returns: a new #GOutputStream
 264  **/
 265 GOutputStream *
 266 g_unix_output_stream_new (gint     fd,
 267                           gboolean close_fd)
 268 {
 269   GUnixOutputStream *stream;
 270
 271   g_return_val_if_fail (fd != -1, NULL);
 272
 273   stream = g_object_new (G_TYPE_UNIX_OUTPUT_STREAM,
 274                          "fd", fd,
 275                          "close-fd", close_fd,
 276                          NULL);
 277
 278   return G_OUTPUT_STREAM (stream);
 279 }
 280
 281 /**
 282  * g_unix_output_stream_set_close_fd:
 283  * @stream: a #GUnixOutputStream
 284  * @close_fd: %TRUE to close the file descriptor when done
 285  *
 286  * Sets whether the file descriptor of @stream shall be closed
 287  * when the stream is closed.
 288  *
 289  * Since: 2.20
 290  */
 291 void
 292 g_unix_output_stream_set_close_fd (GUnixOutputStream *stream,
 293                                    gboolean           close_fd)
 294 {
 295   g_return_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream));
 296
 297   close_fd = close_fd != FALSE;
 298   if (stream->priv->close_fd != close_fd)
 299     {
 300       stream->priv->close_fd = close_fd;
 301       g_object_notify (G_OBJECT (stream), "close-fd");
 302     }
 303 }
 304
 305 /**
 306  * g_unix_output_stream_get_close_fd:
 307  * @stream: a #GUnixOutputStream
 308  *
 309  * Returns whether the file descriptor of @stream will be
 310  * closed when the stream is closed.
 311  *
 312  * Return value: %TRUE if the file descriptor is closed when done
 313  *
 314  * Since: 2.20
 315  */
 316 gboolean
 317 g_unix_output_stream_get_close_fd (GUnixOutputStream *stream)
 318 {
 319   g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), FALSE);
 320
 321   return stream->priv->close_fd;
 322 }
 323
 324 /**
 325  * g_unix_output_stream_get_fd:
 326  * @stream: a #GUnixOutputStream
 327  *
 328  * Return the UNIX file descriptor that the stream writes to.
 329  *
 330  * Return value: The file descriptor of @stream
 331  *
 332  * Since: 2.20
 333  */
 334 gint
 335 g_unix_output_stream_get_fd (GUnixOutputStream *stream)
 336 {
 337   g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), -1);
 338
 339   return stream->priv->fd;
 340 }
 341
 342 static gssize
 343 g_unix_output_stream_write (GOutputStream  *stream,
 344                             const void     *buffer,
 345                             gsize           count,
 346                             GCancellable   *cancellable,
 347                             GError        **error)
 348 {
 349   GUnixOutputStream *unix_stream;
 350   gssize res;
 351   GPollFD poll_fds[2];
 352   int poll_ret;
 353
 354   unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 355
 356   if (unix_stream->priv->is_pipe_or_socket &&
 357       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
 358     {
 359       poll_fds[0].fd = unix_stream->priv->fd;
 360       poll_fds[0].events = G_IO_OUT;
 361       do
 362         poll_ret = g_poll (poll_fds, 2, -1);
 363       while (poll_ret == -1 && errno == EINTR);
 364       g_cancellable_release_fd (cancellable);
 365
 366       if (poll_ret == -1)
 367         {
 368           int errsv = errno;
 369
 370           g_set_error (error, G_IO_ERROR,
 371                        g_io_error_from_errno (errsv),
 372                        _("Error writing to unix: %s"),
 373                        g_strerror (errsv));
 374           return -1;
 375         }
 376     }
 377
 378   while (1)
 379     {
 380       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 381         return -1;
 382
 383       res = write (unix_stream->priv->fd, buffer, count);
 384       if (res == -1)
 385         {
 386           int errsv = errno;
 387
 388           if (errsv == EINTR)
 389             continue;
 390
 391           g_set_error (error, G_IO_ERROR,
 392                        g_io_error_from_errno (errsv),
 393                        _("Error writing to unix: %s"),
 394                        g_strerror (errsv));
 395         }
 396
 397       break;
 398     }
 399
 400   return res;
 401 }
 402
 403 static gboolean
 404 g_unix_output_stream_close (GOutputStream  *stream,
 405                             GCancellable   *cancellable,
 406                             GError        **error)
 407 {
 408   GUnixOutputStream *unix_stream;
 409   int res;
 410
 411   unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 412
 413   if (!unix_stream->priv->close_fd)
 414     return TRUE;
 415
 416   while (1)
 417     {
 418       /* This might block during the close. Doesn't seem to be a way to avoid it though. */
 419       res = close (unix_stream->priv->fd);
 420       if (res == -1)
 421         {
 422           int errsv = errno;
 423
 424           g_set_error (error, G_IO_ERROR,
 425                        g_io_error_from_errno (errsv),
 426                        _("Error closing unix: %s"),
 427                        g_strerror (errsv));
 428         }
 429       break;
 430     }
 431
 432   return res != -1;
 433 }
 434
 435 typedef struct {
 436   gsize count;
 437   const void *buffer;
 438   GAsyncReadyCallback callback;
 439   gpointer user_data;
 440   GCancellable *cancellable;
 441   GUnixOutputStream *stream;
 442 } WriteAsyncData;
 443
 444 static gboolean
 445 write_async_cb (int             fd,
 446                 GIOCondition    condition,
 447                 WriteAsyncData *data)
 448 {
 449   GSimpleAsyncResult *simple;
 450   GError *error = NULL;
 451   gssize count_written;
 452
 453   while (1)
 454     {
 455       if (g_cancellable_set_error_if_cancelled (data->cancellable, &error))
 456         {
 457           count_written = -1;
 458           break;
 459         }
 460
 461       count_written = write (data->stream->priv->fd, data->buffer, data->count);
 462       if (count_written == -1)
 463         {
 464           int errsv = errno;
 465
 466           if (errsv == EINTR)
 467             continue;
 468
 469           g_set_error (&error, G_IO_ERROR,
 470                        g_io_error_from_errno (errsv),
 471                        _("Error writing to unix: %s"),
 472                        g_strerror (errsv));
 473         }
 474       break;
 475     }
 476
 477   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 478                                       data->callback,
 479                                       data->user_data,
 480                                       g_unix_output_stream_write_async);
 481
 482   g_simple_async_result_set_op_res_gssize (simple, count_written);
 483
 484   if (count_written == -1)
 485     g_simple_async_result_take_error (simple, error);
 486
 487   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 488   g_simple_async_result_complete (simple);
 489   g_object_unref (simple);
 490
 491   return FALSE;
 492 }
 493
 494 static void
 495 g_unix_output_stream_write_async (GOutputStream       *stream,
 496                                   const void          *buffer,
 497                                   gsize                count,
 498                                   int                  io_priority,
 499                                   GCancellable        *cancellable,
 500                                   GAsyncReadyCallback  callback,
 501                                   gpointer             user_data)
 502 {
 503   GSource *source;
 504   GUnixOutputStream *unix_stream;
 505   WriteAsyncData *data;
 506
 507   unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 508
 509   if (!unix_stream->priv->is_pipe_or_socket)
 510     {
 511       G_OUTPUT_STREAM_CLASS (g_unix_output_stream_parent_class)->
 512         write_async (stream, buffer, count, io_priority,
 513                      cancellable, callback, user_data);
 514       return;
 515     }
 516
 517   data = g_new0 (WriteAsyncData, 1);
 518   data->count = count;
 519   data->buffer = buffer;
 520   data->callback = callback;
 521   data->user_data = user_data;
 522   data->cancellable = cancellable;
 523   data->stream = unix_stream;
 524
 525   source = _g_fd_source_new (unix_stream->priv->fd,
 526                              G_IO_OUT,
 527                              cancellable);
 528   g_source_set_name (source, "GUnixOutputStream");
 529
 530   g_source_set_callback (source, (GSourceFunc)write_async_cb, data, g_free);
 531   g_source_attach (source, g_main_context_get_thread_default ());
 532
 533   g_source_unref (source);
 534 }
 535
 536 static gssize
 537 g_unix_output_stream_write_finish (GOutputStream  *stream,
 538                                    GAsyncResult   *result,
 539                                    GError        **error)
 540 {
 541   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 542   GSimpleAsyncResult *simple;
 543   gssize nwritten;
 544
 545   if (!unix_stream->priv->is_pipe_or_socket)
 546     {
 547       return G_OUTPUT_STREAM_CLASS (g_unix_output_stream_parent_class)->
 548         write_finish (stream, result, error);
 549     }
 550
 551   simple = G_SIMPLE_ASYNC_RESULT (result);
 552   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_unix_output_stream_write_async);
 553
 554   nwritten = g_simple_async_result_get_op_res_gssize (simple);
 555   return nwritten;
 556 }
 557
 558 typedef struct {
 559   GOutputStream *stream;
 560   GAsyncReadyCallback callback;
 561   gpointer user_data;
 562 } CloseAsyncData;
 563
 564 static gboolean
 565 close_async_cb (CloseAsyncData *data)
 566 {
 567   GUnixOutputStream *unix_stream;
 568   GSimpleAsyncResult *simple;
 569   GError *error = NULL;
 570   gboolean result;
 571   int res;
 572
 573   unix_stream = G_UNIX_OUTPUT_STREAM (data->stream);
 574
 575   if (!unix_stream->priv->close_fd)
 576     {
 577       result = TRUE;
 578       goto out;
 579     }
 580
 581   while (1)
 582     {
 583       res = close (unix_stream->priv->fd);
 584       if (res == -1)
 585         {
 586           int errsv = errno;
 587
 588           g_set_error (&error, G_IO_ERROR,
 589                        g_io_error_from_errno (errsv),
 590                        _("Error closing unix: %s"),
 591                        g_strerror (errsv));
 592         }
 593       break;
 594     }
 595
 596   result = res != -1;
 597
 598  out:
 599   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 600                                       data->callback,
 601                                       data->user_data,
 602                                       g_unix_output_stream_close_async);
 603
 604   if (!result)
 605     g_simple_async_result_take_error (simple, error);
 606
 607   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 608   g_simple_async_result_complete (simple);
 609   g_object_unref (simple);
 610
 611   return FALSE;
 612 }
 613
 614 static void
 615 g_unix_output_stream_close_async (GOutputStream        *stream,
 616                                   int                  io_priority,
 617                                   GCancellable        *cancellable,
 618                                   GAsyncReadyCallback  callback,
 619                                   gpointer             user_data)
 620 {
 621   GSource *idle;
 622   CloseAsyncData *data;
 623
 624   data = g_new0 (CloseAsyncData, 1);
 625
 626   data->stream = stream;
 627   data->callback = callback;
 628   data->user_data = user_data;
 629
 630   idle = g_idle_source_new ();
 631   g_source_set_callback (idle, (GSourceFunc)close_async_cb, data, g_free);
 632   g_source_attach (idle, g_main_context_get_thread_default ());
 633   g_source_unref (idle);
 634 }
 635
 636 static gboolean
 637 g_unix_output_stream_close_finish (GOutputStream  *stream,
 638                                    GAsyncResult   *result,
 639                                    GError        **error)
 640 {
 641   /* Failures handled in generic close_finish code */
 642   return TRUE;
 643 }
 644
 645 static gboolean
 646 g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream)
 647 {
 648   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 649   GPollFD poll_fd;
 650   gint result;
 651
 652   poll_fd.fd = unix_stream->priv->fd;
 653   poll_fd.events = G_IO_OUT;
 654
 655   do
 656     result = g_poll (&poll_fd, 1, 0);
 657   while (result == -1 && errno == EINTR);
 658
 659   return poll_fd.revents != 0;
 660 }
 661
 662 static GSource *
 663 g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
 664                                              GCancellable          *cancellable)
 665 {
 666   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 667   GSource *inner_source, *pollable_source;
 668
 669   pollable_source = g_pollable_source_new (G_OBJECT (stream));
 670
 671   inner_source = _g_fd_source_new (unix_stream->priv->fd, G_IO_OUT, cancellable);
 672   g_source_set_dummy_callback (inner_source);
 673   g_source_add_child_source (pollable_source, inner_source);
 674   g_source_unref (inner_source);
 675
 676   return pollable_source;
 677 }