gio/gunixinputstream.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 2.1 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, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Author: Alexander Larsson <alexl@redhat.com>
  19  */
  20
  21 #include "config.h"
  22
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <stdio.h>
  26
  27 #include <glib.h>
  28 #include <glib/gstdio.h>
  29 #include <glib/glib-unix.h>
  30 #include "gioerror.h"
  31 #include "gunixinputstream.h"
  32 #include "gcancellable.h"
  33 #include "gasynchelper.h"
  34 #include "gfiledescriptorbased.h"
  35 #include "glibintl.h"
  36 #include "giounix-private.h"
  37
  38
  39 /**
  40  * SECTION:gunixinputstream
  41  * @short_description: Streaming input operations for UNIX file descriptors
  42  * @include: gio/gunixinputstream.h
  43  * @see_also: #GInputStream
  44  *
  45  * #GUnixInputStream implements #GInputStream for reading from a UNIX
  46  * file descriptor, including asynchronous operations. (If the file
  47  * descriptor refers to a socket or pipe, this will use poll() to do
  48  * asynchronous I/O. If it refers to a regular file, it will fall back
  49  * to doing asynchronous I/O in another thread.)
  50  *
  51  * Note that `<gio/gunixinputstream.h>` belongs to the UNIX-specific GIO
  52  * interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config
  53  * file when using it.
  54  */
  55
  56 enum {
  57   PROP_0,
  58   PROP_FD,
  59   PROP_CLOSE_FD
  60 };
  61
  62 struct _GUnixInputStreamPrivate {
  63   int fd;
  64   guint close_fd : 1;
  65   guint can_poll : 1;
  66 };
  67
  68 static void g_unix_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface);
  69 static void g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);
  70
  71 G_DEFINE_TYPE_WITH_CODE (GUnixInputStream, g_unix_input_stream, G_TYPE_INPUT_STREAM,
  72                          G_ADD_PRIVATE (GUnixInputStream)
  73                          G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_INPUT_STREAM,
  74                                                 g_unix_input_stream_pollable_iface_init)
  75                          G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
  76                                                 g_unix_input_stream_file_descriptor_based_iface_init)
  77                          )
  78
  79 static void     g_unix_input_stream_set_property (GObject              *object,
  80                                                   guint                 prop_id,
  81                                                   const GValue         *value,
  82                                                   GParamSpec           *pspec);
  83 static void     g_unix_input_stream_get_property (GObject              *object,
  84                                                   guint                 prop_id,
  85                                                   GValue               *value,
  86                                                   GParamSpec           *pspec);
  87 static gssize   g_unix_input_stream_read         (GInputStream         *stream,
  88                                                   void                 *buffer,
  89                                                   gsize                 count,
  90                                                   GCancellable         *cancellable,
  91                                                   GError              **error);
  92 static gboolean g_unix_input_stream_close        (GInputStream         *stream,
  93                                                   GCancellable         *cancellable,
  94                                                   GError              **error);
  95 static void     g_unix_input_stream_skip_async   (GInputStream         *stream,
  96                                                   gsize                 count,
  97                                                   int                   io_priority,
  98                                                   GCancellable         *cancellable,
  99                                                   GAsyncReadyCallback   callback,
 100                                                   gpointer              data);
 101 static gssize   g_unix_input_stream_skip_finish  (GInputStream         *stream,
 102                                                   GAsyncResult         *result,
 103                                                   GError              **error);
 104
 105 static gboolean g_unix_input_stream_pollable_can_poll      (GPollableInputStream *stream);
 106 static gboolean g_unix_input_stream_pollable_is_readable   (GPollableInputStream *stream);
 107 static GSource *g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,
 108                                                             GCancellable         *cancellable);
 109
 110 static void
 111 g_unix_input_stream_class_init (GUnixInputStreamClass *klass)
 112 {
 113   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 114   GInputStreamClass *stream_class = G_INPUT_STREAM_CLASS (klass);
 115
 116   gobject_class->get_property = g_unix_input_stream_get_property;
 117   gobject_class->set_property = g_unix_input_stream_set_property;
 118
 119   stream_class->read_fn = g_unix_input_stream_read;
 120   stream_class->close_fn = g_unix_input_stream_close;
 121   if (0)
 122     {
 123       /* TODO: Implement instead of using fallbacks */
 124       stream_class->skip_async = g_unix_input_stream_skip_async;
 125       stream_class->skip_finish = g_unix_input_stream_skip_finish;
 126     }
 127
 128   /**
 129    * GUnixInputStream:fd:
 130    *
 131    * The file descriptor that the stream reads from.
 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 read from"),
 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    * GUnixInputStream: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_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface)
 161 {
 162   iface->can_poll = g_unix_input_stream_pollable_can_poll;
 163   iface->is_readable = g_unix_input_stream_pollable_is_readable;
 164   iface->create_source = g_unix_input_stream_pollable_create_source;
 165 }
 166
 167 static void
 168 g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
 169 {
 170   iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_input_stream_get_fd;
 171 }
 172
 173 static void
 174 g_unix_input_stream_set_property (GObject         *object,
 175                                   guint            prop_id,
 176                                   const GValue    *value,
 177                                   GParamSpec      *pspec)
 178 {
 179   GUnixInputStream *unix_stream;
 180
 181   unix_stream = G_UNIX_INPUT_STREAM (object);
 182
 183   switch (prop_id)
 184     {
 185     case PROP_FD:
 186       unix_stream->priv->fd = g_value_get_int (value);
 187       unix_stream->priv->can_poll = _g_fd_is_pollable (unix_stream->priv->fd);
 188       break;
 189     case PROP_CLOSE_FD:
 190       unix_stream->priv->close_fd = g_value_get_boolean (value);
 191       break;
 192     default:
 193       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 194       break;
 195     }
 196 }
 197
 198 static void
 199 g_unix_input_stream_get_property (GObject    *object,
 200                                   guint       prop_id,
 201                                   GValue     *value,
 202                                   GParamSpec *pspec)
 203 {
 204   GUnixInputStream *unix_stream;
 205
 206   unix_stream = G_UNIX_INPUT_STREAM (object);
 207
 208   switch (prop_id)
 209     {
 210     case PROP_FD:
 211       g_value_set_int (value, unix_stream->priv->fd);
 212       break;
 213     case PROP_CLOSE_FD:
 214       g_value_set_boolean (value, unix_stream->priv->close_fd);
 215       break;
 216     default:
 217       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 218     }
 219 }
 220
 221 static void
 222 g_unix_input_stream_init (GUnixInputStream *unix_stream)
 223 {
 224   unix_stream->priv = g_unix_input_stream_get_instance_private (unix_stream);
 225   unix_stream->priv->fd = -1;
 226   unix_stream->priv->close_fd = TRUE;
 227 }
 228
 229 /**
 230  * g_unix_input_stream_new:
 231  * @fd: a UNIX file descriptor
 232  * @close_fd: %TRUE to close the file descriptor when done
 233  *
 234  * Creates a new #GUnixInputStream for the given @fd.
 235  *
 236  * If @close_fd is %TRUE, the file descriptor will be closed
 237  * when the stream is closed.
 238  *
 239  * Returns: a new #GUnixInputStream
 240  **/
 241 GInputStream *
 242 g_unix_input_stream_new (gint     fd,
 243                          gboolean close_fd)
 244 {
 245   GUnixInputStream *stream;
 246
 247   g_return_val_if_fail (fd != -1, NULL);
 248
 249   stream = g_object_new (G_TYPE_UNIX_INPUT_STREAM,
 250                          "fd", fd,
 251                          "close-fd", close_fd,
 252                          NULL);
 253
 254   return G_INPUT_STREAM (stream);
 255 }
 256
 257 /**
 258  * g_unix_input_stream_set_close_fd:
 259  * @stream: a #GUnixInputStream
 260  * @close_fd: %TRUE to close the file descriptor when done
 261  *
 262  * Sets whether the file descriptor of @stream shall be closed
 263  * when the stream is closed.
 264  *
 265  * Since: 2.20
 266  */
 267 void
 268 g_unix_input_stream_set_close_fd (GUnixInputStream *stream,
 269                                   gboolean          close_fd)
 270 {
 271   g_return_if_fail (G_IS_UNIX_INPUT_STREAM (stream));
 272
 273   close_fd = close_fd != FALSE;
 274   if (stream->priv->close_fd != close_fd)
 275     {
 276       stream->priv->close_fd = close_fd;
 277       g_object_notify (G_OBJECT (stream), "close-fd");
 278     }
 279 }
 280
 281 /**
 282  * g_unix_input_stream_get_close_fd:
 283  * @stream: a #GUnixInputStream
 284  *
 285  * Returns whether the file descriptor of @stream will be
 286  * closed when the stream is closed.
 287  *
 288  * Returns: %TRUE if the file descriptor is closed when done
 289  *
 290  * Since: 2.20
 291  */
 292 gboolean
 293 g_unix_input_stream_get_close_fd (GUnixInputStream *stream)
 294 {
 295   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), FALSE);
 296
 297   return stream->priv->close_fd;
 298 }
 299
 300 /**
 301  * g_unix_input_stream_get_fd:
 302  * @stream: a #GUnixInputStream
 303  *
 304  * Return the UNIX file descriptor that the stream reads from.
 305  *
 306  * Returns: The file descriptor of @stream
 307  *
 308  * Since: 2.20
 309  */
 310 gint
 311 g_unix_input_stream_get_fd (GUnixInputStream *stream)
 312 {
 313   g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), -1);
 314
 315   return stream->priv->fd;
 316 }
 317
 318 static gssize
 319 g_unix_input_stream_read (GInputStream  *stream,
 320                           void          *buffer,
 321                           gsize          count,
 322                           GCancellable  *cancellable,
 323                           GError       **error)
 324 {
 325   GUnixInputStream *unix_stream;
 326   gssize res = -1;
 327   GPollFD poll_fds[2];
 328   int nfds;
 329   int poll_ret;
 330
 331   unix_stream = G_UNIX_INPUT_STREAM (stream);
 332
 333   poll_fds[0].fd = unix_stream->priv->fd;
 334   poll_fds[0].events = G_IO_IN;
 335   if (unix_stream->priv->can_poll &&
 336       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
 337     nfds = 2;
 338   else
 339     nfds = 1;
 340
 341   while (1)
 342     {
 343       int errsv;
 344
 345       poll_fds[0].revents = poll_fds[1].revents = 0;
 346       do
 347         {
 348           poll_ret = g_poll (poll_fds, nfds, -1);
 349           errsv = errno;
 350         }
 351       while (poll_ret == -1 && errsv == EINTR);
 352
 353       if (poll_ret == -1)
 354         {
 355           g_set_error (error, G_IO_ERROR,
 356                        g_io_error_from_errno (errsv),
 357                        _("Error reading from 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 = read (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 reading from 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_input_stream_close (GInputStream  *stream,
 392                            GCancellable  *cancellable,
 393                            GError       **error)
 394 {
 395   GUnixInputStream *unix_stream;
 396   int res;
 397
 398   unix_stream = G_UNIX_INPUT_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_input_stream_skip_async (GInputStream        *stream,
 420                                 gsize                count,
 421                                 int                  io_priority,
 422                                 GCancellable        *cancellable,
 423                                 GAsyncReadyCallback  callback,
 424                                 gpointer             data)
 425 {
 426   g_warn_if_reached ();
 427   /* TODO: Not implemented */
 428 }
 429
 430 static gssize
 431 g_unix_input_stream_skip_finish  (GInputStream  *stream,
 432                                   GAsyncResult  *result,
 433                                   GError       **error)
 434 {
 435   g_warn_if_reached ();
 436   return 0;
 437   /* TODO: Not implemented */
 438 }
 439
 440 static gboolean
 441 g_unix_input_stream_pollable_can_poll (GPollableInputStream *stream)
 442 {
 443   return G_UNIX_INPUT_STREAM (stream)->priv->can_poll;
 444 }
 445
 446 static gboolean
 447 g_unix_input_stream_pollable_is_readable (GPollableInputStream *stream)
 448 {
 449   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 450   GPollFD poll_fd;
 451   gint result;
 452
 453   poll_fd.fd = unix_stream->priv->fd;
 454   poll_fd.events = G_IO_IN;
 455   poll_fd.revents = 0;
 456
 457   do
 458     result = g_poll (&poll_fd, 1, 0);
 459   while (result == -1 && errno == EINTR);
 460
 461   return poll_fd.revents != 0;
 462 }
 463
 464 static GSource *
 465 g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,
 466                                             GCancellable         *cancellable)
 467 {
 468   GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);
 469   GSource *inner_source, *cancellable_source, *pollable_source;
 470
 471   pollable_source = g_pollable_source_new (G_OBJECT (stream));
 472
 473   inner_source = g_unix_fd_source_new (unix_stream->priv->fd, G_IO_IN);
 474   g_source_set_dummy_callback (inner_source);
 475   g_source_add_child_source (pollable_source, inner_source);
 476   g_source_unref (inner_source);
 477
 478   if (cancellable)
 479     {
 480       cancellable_source = g_cancellable_source_new (cancellable);
 481       g_source_set_dummy_callback (cancellable_source);
 482       g_source_add_child_source (pollable_source, cancellable_source);
 483       g_source_unref (cancellable_source);
 484     }
 485
 486   return pollable_source;
 487 }