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 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 #include <poll.h>
  32
  33 #include <glib.h>
  34 #include <glib/gstdio.h>
  35 #include "gioerror.h"
  36 #include "gsimpleasyncresult.h"
  37 #include "gunixinputstream.h"
  38 #include "gcancellable.h"
  39 #include "gasynchelper.h"
  40 #include "glibintl.h"
  41
  42 /**
  43  * SECTION:gunixinputstream
  44  * @short_description: Unix Input Stream
  45  * @see_also: #GInputStream
  46  *
  47  * #GUnixInputStream implements #GInputStream for reading from a
  48  * unix file descriptor, including asynchronous operations. The file
  49  * descriptor much be selectable, so it doesn't work with opened files.
  50  **/
  51
  52 G_DEFINE_TYPE (GUnixInputStream, g_unix_input_stream, G_TYPE_INPUT_STREAM);
  53
  54 struct _GUnixInputStreamPrivate {
  55   int fd;
  56   gboolean close_fd_at_close;
  57 };
  58
  59 static gssize   g_unix_input_stream_read         (GInputStream         *stream,
  60                                                   void                 *buffer,
  61                                                   gsize                 count,
  62                                                   GCancellable         *cancellable,
  63                                                   GError              **error);
  64 static gboolean g_unix_input_stream_close        (GInputStream         *stream,
  65                                                   GCancellable         *cancellable,
  66                                                   GError              **error);
  67 static void     g_unix_input_stream_read_async   (GInputStream         *stream,
  68                                                   void                 *buffer,
  69                                                   gsize                 count,
  70                                                   int                   io_priority,
  71                                                   GCancellable         *cancellable,
  72                                                   GAsyncReadyCallback   callback,
  73                                                   gpointer              data);
  74 static gssize   g_unix_input_stream_read_finish  (GInputStream         *stream,
  75                                                   GAsyncResult         *result,
  76                                                   GError              **error);
  77 static void     g_unix_input_stream_skip_async   (GInputStream         *stream,
  78                                                   gsize                 count,
  79                                                   int                   io_priority,
  80                                                   GCancellable         *cancellable,
  81                                                   GAsyncReadyCallback   callback,
  82                                                   gpointer              data);
  83 static gssize   g_unix_input_stream_skip_finish  (GInputStream         *stream,
  84                                                   GAsyncResult         *result,
  85                                                   GError              **error);
  86 static void     g_unix_input_stream_close_async  (GInputStream         *stream,
  87                                                   int                   io_priority,
  88                                                   GCancellable         *cancellable,
  89                                                   GAsyncReadyCallback   callback,
  90                                                   gpointer              data);
  91 static gboolean g_unix_input_stream_close_finish (GInputStream         *stream,
  92                                                   GAsyncResult         *result,
  93                                                   GError              **error);
  94
  95
  96 static void
  97 g_unix_input_stream_finalize (GObject *object)
  98 {
  99   GUnixInputStream *stream;
 100
 101   stream = G_UNIX_INPUT_STREAM (object);
 102
 103   if (G_OBJECT_CLASS (g_unix_input_stream_parent_class)->finalize)
 104     (*G_OBJECT_CLASS (g_unix_input_stream_parent_class)->finalize) (object);
 105 }
 106
 107 static void
 108 g_unix_input_stream_class_init (GUnixInputStreamClass *klass)
 109 {
 110   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 111   GInputStreamClass *stream_class = G_INPUT_STREAM_CLASS (klass);
 112
 113   g_type_class_add_private (klass, sizeof (GUnixInputStreamPrivate));
 114
 115   gobject_class->finalize = g_unix_input_stream_finalize;
 116
 117   stream_class->read = g_unix_input_stream_read;
 118   stream_class->close = g_unix_input_stream_close;
 119   stream_class->read_async = g_unix_input_stream_read_async;
 120   stream_class->read_finish = g_unix_input_stream_read_finish;
 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   stream_class->close_async = g_unix_input_stream_close_async;
 128   stream_class->close_finish = g_unix_input_stream_close_finish;
 129 }
 130
 131 static void
 132 g_unix_input_stream_init (GUnixInputStream *unix_stream)
 133 {
 134   unix_stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (unix_stream,
 135                                                    G_TYPE_UNIX_INPUT_STREAM,
 136                                                    GUnixInputStreamPrivate);
 137 }
 138
 139 /**
 140  * g_unix_input_stream_new:
 141  * @fd: unix file descriptor.
 142  * @close_fd_at_close: a #gboolean.
 143  *
 144  * Creates a new #GUnixInputStream for the given @fd. If @close_fd_at_close
 145  * is %TRUE, the file descriptor will be closed when the stream is closed.
 146  *
 147  * Returns: a #GUnixInputStream.
 148  **/
 149 GInputStream *
 150 g_unix_input_stream_new (int fd,
 151                          gboolean close_fd_at_close)
 152 {
 153   GUnixInputStream *stream;
 154
 155   g_return_val_if_fail (fd != -1, NULL);
 156
 157   stream = g_object_new (G_TYPE_UNIX_INPUT_STREAM, NULL);
 158
 159   stream->priv->fd = fd;
 160   stream->priv->close_fd_at_close = close_fd_at_close;
 161
 162   return G_INPUT_STREAM (stream);
 163 }
 164
 165 static gssize
 166 g_unix_input_stream_read (GInputStream *stream,
 167                           void         *buffer,
 168                           gsize         count,
 169                           GCancellable *cancellable,
 170                           GError      **error)
 171 {
 172   GUnixInputStream *unix_stream;
 173   gssize res;
 174   struct pollfd poll_fds[2];
 175   int poll_ret;
 176   int cancel_fd;
 177
 178   unix_stream = G_UNIX_INPUT_STREAM (stream);
 179
 180   cancel_fd = g_cancellable_get_fd (cancellable);
 181   if (cancel_fd != -1)
 182     {
 183       do
 184         {
 185           poll_fds[0].events = POLLIN;
 186           poll_fds[0].fd = unix_stream->priv->fd;
 187           poll_fds[1].events = POLLIN;
 188           poll_fds[1].fd = cancel_fd;
 189           poll_ret = poll (poll_fds, 2, -1);
 190         }
 191       while (poll_ret == -1 && errno == EINTR);
 192
 193       if (poll_ret == -1)
 194         {
 195           g_set_error (error, G_IO_ERROR,
 196                        g_io_error_from_errno (errno),
 197                        _("Error reading from unix: %s"),
 198                        g_strerror (errno));
 199           return -1;
 200         }
 201     }
 202
 203   while (1)
 204     {
 205       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 206         break;
 207       res = read (unix_stream->priv->fd, buffer, count);
 208       if (res == -1)
 209         {
 210           if (errno == EINTR)
 211             continue;
 212
 213           g_set_error (error, G_IO_ERROR,
 214                        g_io_error_from_errno (errno),
 215                        _("Error reading from unix: %s"),
 216                        g_strerror (errno));
 217         }
 218
 219       break;
 220     }
 221
 222   return res;
 223 }
 224
 225 static gboolean
 226 g_unix_input_stream_close (GInputStream *stream,
 227                            GCancellable *cancellable,
 228                            GError      **error)
 229 {
 230   GUnixInputStream *unix_stream;
 231   int res;
 232
 233   unix_stream = G_UNIX_INPUT_STREAM (stream);
 234
 235   if (!unix_stream->priv->close_fd_at_close)
 236     return TRUE;
 237
 238   while (1)
 239     {
 240       /* This might block during the close. Doesn't seem to be a way to avoid it though. */
 241       res = close (unix_stream->priv->fd);
 242       if (res == -1)
 243         {
 244           g_set_error (error, G_IO_ERROR,
 245                        g_io_error_from_errno (errno),
 246                        _("Error closing unix: %s"),
 247                        g_strerror (errno));
 248         }
 249       break;
 250     }
 251
 252   return res != -1;
 253 }
 254
 255 typedef struct {
 256   gsize count;
 257   void *buffer;
 258   GAsyncReadyCallback callback;
 259   gpointer user_data;
 260   GCancellable *cancellable;
 261   GUnixInputStream *stream;
 262 } ReadAsyncData;
 263
 264 static gboolean
 265 read_async_cb (ReadAsyncData *data,
 266                GIOCondition condition,
 267                int fd)
 268 {
 269   GSimpleAsyncResult *simple;
 270   GError *error = NULL;
 271   gssize count_read;
 272
 273   /* We know that we can read from fd once without blocking */
 274   while (1)
 275     {
 276       if (g_cancellable_set_error_if_cancelled (data->cancellable, &error))
 277         {
 278           count_read = -1;
 279           break;
 280         }
 281       count_read = read (data->stream->priv->fd, data->buffer, data->count);
 282       if (count_read == -1)
 283         {
 284           if (errno == EINTR)
 285             continue;
 286
 287           g_set_error (&error, G_IO_ERROR,
 288                        g_io_error_from_errno (errno),
 289                        _("Error reading from unix: %s"),
 290                        g_strerror (errno));
 291         }
 292       break;
 293     }
 294
 295   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 296                                       data->callback,
 297                                       data->user_data,
 298                                       g_unix_input_stream_read_async);
 299
 300   g_simple_async_result_set_op_res_gssize (simple, count_read);
 301
 302   if (count_read == -1)
 303     {
 304       g_simple_async_result_set_from_error (simple, error);
 305       g_error_free (error);
 306     }
 307
 308   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 309   g_simple_async_result_complete (simple);
 310   g_object_unref (simple);
 311
 312   return FALSE;
 313 }
 314
 315 static void
 316 g_unix_input_stream_read_async (GInputStream        *stream,
 317                                 void                *buffer,
 318                                 gsize                count,
 319                                 int                  io_priority,
 320                                 GCancellable        *cancellable,
 321                                 GAsyncReadyCallback  callback,
 322                                 gpointer             user_data)
 323 {
 324   GSource *source;
 325   GUnixInputStream *unix_stream;
 326   ReadAsyncData *data;
 327
 328   unix_stream = G_UNIX_INPUT_STREAM (stream);
 329
 330   data = g_new0 (ReadAsyncData, 1);
 331   data->count = count;
 332   data->buffer = buffer;
 333   data->callback = callback;
 334   data->user_data = user_data;
 335   data->cancellable = cancellable;
 336   data->stream = unix_stream;
 337
 338   source = _g_fd_source_new (unix_stream->priv->fd,
 339                              POLLIN,
 340                              cancellable);
 341
 342   g_source_set_callback (source, (GSourceFunc)read_async_cb, data, g_free);
 343   g_source_attach (source, NULL);
 344
 345   g_source_unref (source);
 346 }
 347
 348 static gssize
 349 g_unix_input_stream_read_finish (GInputStream              *stream,
 350                                  GAsyncResult              *result,
 351                                  GError                   **error)
 352 {
 353   GSimpleAsyncResult *simple;
 354   gssize nread;
 355
 356   simple = G_SIMPLE_ASYNC_RESULT (result);
 357   g_assert (g_simple_async_result_get_source_tag (simple) == g_unix_input_stream_read_async);
 358
 359   nread = g_simple_async_result_get_op_res_gssize (simple);
 360   return nread;
 361 }
 362
 363 static void
 364 g_unix_input_stream_skip_async (GInputStream        *stream,
 365                                 gsize                count,
 366                                 int                  io_priority,
 367                                 GCancellable        *cancellable,
 368                                 GAsyncReadyCallback  callback,
 369                                 gpointer             data)
 370 {
 371   g_assert_not_reached ();
 372   /* TODO: Not implemented */
 373 }
 374
 375 static gssize
 376 g_unix_input_stream_skip_finish  (GInputStream              *stream,
 377                                   GAsyncResult              *result,
 378                                   GError                   **error)
 379 {
 380   g_assert_not_reached ();
 381   /* TODO: Not implemented */
 382 }
 383
 384
 385 typedef struct {
 386   GInputStream *stream;
 387   GAsyncReadyCallback callback;
 388   gpointer user_data;
 389 } CloseAsyncData;
 390
 391 static void
 392 close_async_data_free (gpointer _data)
 393 {
 394   CloseAsyncData *data = _data;
 395
 396   g_free (data);
 397 }
 398
 399 static gboolean
 400 close_async_cb (CloseAsyncData *data)
 401 {
 402   GUnixInputStream *unix_stream;
 403   GSimpleAsyncResult *simple;
 404   GError *error = NULL;
 405   gboolean result;
 406   int res;
 407
 408   unix_stream = G_UNIX_INPUT_STREAM (data->stream);
 409
 410   if (!unix_stream->priv->close_fd_at_close)
 411     {
 412       result = TRUE;
 413       goto out;
 414     }
 415
 416   while (1)
 417     {
 418       res = close (unix_stream->priv->fd);
 419       if (res == -1)
 420         {
 421           g_set_error (&error, G_IO_ERROR,
 422                        g_io_error_from_errno (errno),
 423                        _("Error closing unix: %s"),
 424                        g_strerror (errno));
 425         }
 426       break;
 427     }
 428
 429   result = res != -1;
 430
 431  out:
 432   simple = g_simple_async_result_new (G_OBJECT (data->stream),
 433                                       data->callback,
 434                                       data->user_data,
 435                                       g_unix_input_stream_close_async);
 436
 437   if (!result)
 438     {
 439       g_simple_async_result_set_from_error (simple, error);
 440       g_error_free (error);
 441     }
 442
 443   /* Complete immediately, not in idle, since we're already in a mainloop callout */
 444   g_simple_async_result_complete (simple);
 445   g_object_unref (simple);
 446
 447   return FALSE;
 448 }
 449
 450 static void
 451 g_unix_input_stream_close_async (GInputStream       *stream,
 452                                  int                 io_priority,
 453                                  GCancellable       *cancellable,
 454                                  GAsyncReadyCallback callback,
 455                                  gpointer            user_data)
 456 {
 457   GSource *idle;
 458   CloseAsyncData *data;
 459
 460   data = g_new0 (CloseAsyncData, 1);
 461
 462   data->stream = stream;
 463   data->callback = callback;
 464   data->user_data = user_data;
 465
 466   idle = g_idle_source_new ();
 467   g_source_set_callback (idle, (GSourceFunc)close_async_cb, data, close_async_data_free);
 468   g_source_attach (idle, NULL);
 469   g_source_unref (idle);
 470 }
 471
 472 static gboolean
 473 g_unix_input_stream_close_finish (GInputStream              *stream,
 474                                   GAsyncResult              *result,
 475                                   GError                   **error)
 476 {
 477   /* Failures handled in generic close_finish code */
 478   return TRUE;
 479 }
 480