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#include <sys/uio.h>
27
28#include <glib.h>
29#include <glib/gstdio.h>
30#include <glib/glib-unix.h>
31#include "gioerror.h"
32#include "gunixoutputstream.h"
33#include "gcancellable.h"
34#include "gasynchelper.h"
35#include "gfiledescriptorbased.h"
36#include "glibintl.h"
37#include "gioprivate.h"
38#include "giounix-private.h"
39
40
41/**
42 * SECTION:gunixoutputstream
43 * @short_description: Streaming output operations for UNIX file descriptors
44 * @include: gio/gunixoutputstream.h
45 * @see_also: #GOutputStream
46 *
47 * #GUnixOutputStream implements #GOutputStream for writing to a UNIX
48 * file descriptor, including asynchronous operations. (If the file
49 * descriptor refers to a socket or pipe, this will use poll() to do
50 * asynchronous I/O. If it refers to a regular file, it will fall back
51 * to doing asynchronous I/O in another thread.)
52 *
53 * Note that `<gio/gunixoutputstream.h>` belongs to the UNIX-specific GIO
54 * interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config file
55 * when using it.
56 */
57
58enum {
59 PROP_0,
60 PROP_FD,
61 PROP_CLOSE_FD
62};
63
64struct _GUnixOutputStreamPrivate {
65 int fd;
66 guint close_fd : 1;
67 guint can_poll : 1;
68};
69
70static void g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface);
71static void g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);
72
73G_DEFINE_TYPE_WITH_CODE (GUnixOutputStream, g_unix_output_stream, G_TYPE_OUTPUT_STREAM,
74 G_ADD_PRIVATE (GUnixOutputStream)
75 G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_OUTPUT_STREAM,
76 g_unix_output_stream_pollable_iface_init)
77 G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
78 g_unix_output_stream_file_descriptor_based_iface_init)
79 )
80
81static void g_unix_output_stream_set_property (GObject *object,
82 guint prop_id,
83 const GValue *value,
84 GParamSpec *pspec);
85static void g_unix_output_stream_get_property (GObject *object,
86 guint prop_id,
87 GValue *value,
88 GParamSpec *pspec);
89static gssize g_unix_output_stream_write (GOutputStream *stream,
90 const void *buffer,
91 gsize count,
92 GCancellable *cancellable,
93 GError **error);
94static gboolean g_unix_output_stream_writev (GOutputStream *stream,
95 const GOutputVector *vectors,
96 gsize n_vectors,
97 gsize *bytes_written,
98 GCancellable *cancellable,
99 GError **error);
100static gboolean g_unix_output_stream_close (GOutputStream *stream,
101 GCancellable *cancellable,
102 GError **error);
103
104static gboolean g_unix_output_stream_pollable_can_poll (GPollableOutputStream *stream);
105static gboolean g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream);
106static GSource *g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
107 GCancellable *cancellable);
108static GPollableReturn g_unix_output_stream_pollable_writev_nonblocking (GPollableOutputStream *stream,
109 const GOutputVector *vectors,
110 gsize n_vectors,
111 gsize *bytes_written,
112 GError **error);
113
114static void
115g_unix_output_stream_class_init (GUnixOutputStreamClass *klass)
116{
117 GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
118 GOutputStreamClass *stream_class = G_OUTPUT_STREAM_CLASS (klass);
119
120 gobject_class->get_property = g_unix_output_stream_get_property;
121 gobject_class->set_property = g_unix_output_stream_set_property;
122
123 stream_class->write_fn = g_unix_output_stream_write;
124 stream_class->writev_fn = g_unix_output_stream_writev;
125 stream_class->close_fn = g_unix_output_stream_close;
126
127 /**
128 * GUnixOutputStream:fd:
129 *
130 * The file descriptor that the stream writes to.
131 *
132 * Since: 2.20
133 */
134 g_object_class_install_property (oclass: gobject_class,
135 property_id: PROP_FD,
136 pspec: g_param_spec_int (name: "fd",
137 P_("File descriptor"),
138 P_("The file descriptor to write to"),
139 G_MININT, G_MAXINT, default_value: -1,
140 flags: G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
141
142 /**
143 * GUnixOutputStream:close-fd:
144 *
145 * Whether to close the file descriptor when the stream is closed.
146 *
147 * Since: 2.20
148 */
149 g_object_class_install_property (oclass: gobject_class,
150 property_id: PROP_CLOSE_FD,
151 pspec: g_param_spec_boolean (name: "close-fd",
152 P_("Close file descriptor"),
153 P_("Whether to close the file descriptor when the stream is closed"),
154 TRUE,
155 flags: G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
156}
157
158static void
159g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface)
160{
161 iface->can_poll = g_unix_output_stream_pollable_can_poll;
162 iface->is_writable = g_unix_output_stream_pollable_is_writable;
163 iface->create_source = g_unix_output_stream_pollable_create_source;
164 iface->writev_nonblocking = g_unix_output_stream_pollable_writev_nonblocking;
165}
166
167static void
168g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
169{
170 iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_output_stream_get_fd;
171}
172
173static void
174g_unix_output_stream_set_property (GObject *object,
175 guint prop_id,
176 const GValue *value,
177 GParamSpec *pspec)
178{
179 GUnixOutputStream *unix_stream;
180
181 unix_stream = G_UNIX_OUTPUT_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 (fd: 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
198static void
199g_unix_output_stream_get_property (GObject *object,
200 guint prop_id,
201 GValue *value,
202 GParamSpec *pspec)
203{
204 GUnixOutputStream *unix_stream;
205
206 unix_stream = G_UNIX_OUTPUT_STREAM (object);
207
208 switch (prop_id)
209 {
210 case PROP_FD:
211 g_value_set_int (value, v_int: unix_stream->priv->fd);
212 break;
213 case PROP_CLOSE_FD:
214 g_value_set_boolean (value, v_boolean: unix_stream->priv->close_fd);
215 break;
216 default:
217 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
218 }
219}
220
221static void
222g_unix_output_stream_init (GUnixOutputStream *unix_stream)
223{
224 unix_stream->priv = g_unix_output_stream_get_instance_private (self: unix_stream);
225 unix_stream->priv->fd = -1;
226 unix_stream->priv->close_fd = TRUE;
227}
228
229/**
230 * g_unix_output_stream_new:
231 * @fd: a UNIX file descriptor
232 * @close_fd: %TRUE to close the file descriptor when done
233 *
234 * Creates a new #GUnixOutputStream for the given @fd.
235 *
236 * If @close_fd, is %TRUE, the file descriptor will be closed when
237 * the output stream is destroyed.
238 *
239 * Returns: a new #GOutputStream
240 **/
241GOutputStream *
242g_unix_output_stream_new (gint fd,
243 gboolean close_fd)
244{
245 GUnixOutputStream *stream;
246
247 g_return_val_if_fail (fd != -1, NULL);
248
249 stream = g_object_new (G_TYPE_UNIX_OUTPUT_STREAM,
250 first_property_name: "fd", fd,
251 "close-fd", close_fd,
252 NULL);
253
254 return G_OUTPUT_STREAM (stream);
255}
256
257/**
258 * g_unix_output_stream_set_close_fd:
259 * @stream: a #GUnixOutputStream
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 */
267void
268g_unix_output_stream_set_close_fd (GUnixOutputStream *stream,
269 gboolean close_fd)
270{
271 g_return_if_fail (G_IS_UNIX_OUTPUT_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), property_name: "close-fd");
278 }
279}
280
281/**
282 * g_unix_output_stream_get_close_fd:
283 * @stream: a #GUnixOutputStream
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 */
292gboolean
293g_unix_output_stream_get_close_fd (GUnixOutputStream *stream)
294{
295 g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), FALSE);
296
297 return stream->priv->close_fd;
298}
299
300/**
301 * g_unix_output_stream_get_fd:
302 * @stream: a #GUnixOutputStream
303 *
304 * Return the UNIX file descriptor that the stream writes to.
305 *
306 * Returns: The file descriptor of @stream
307 *
308 * Since: 2.20
309 */
310gint
311g_unix_output_stream_get_fd (GUnixOutputStream *stream)
312{
313 g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), -1);
314
315 return stream->priv->fd;
316}
317
318static gssize
319g_unix_output_stream_write (GOutputStream *stream,
320 const void *buffer,
321 gsize count,
322 GCancellable *cancellable,
323 GError **error)
324{
325 GUnixOutputStream *unix_stream;
326 gssize res = -1;
327 GPollFD poll_fds[2];
328 int nfds = 0;
329 int poll_ret;
330
331 unix_stream = G_UNIX_OUTPUT_STREAM (stream);
332
333 poll_fds[0].fd = unix_stream->priv->fd;
334 poll_fds[0].events = G_IO_OUT;
335 nfds++;
336
337 if (unix_stream->priv->can_poll &&
338 g_cancellable_make_pollfd (cancellable, pollfd: &poll_fds[1]))
339 nfds++;
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 (fds: poll_fds, nfds, timeout: -1);
349 errsv = errno;
350 }
351 while (poll_ret == -1 && errsv == EINTR);
352
353 if (poll_ret == -1)
354 {
355 g_set_error (err: error, G_IO_ERROR,
356 code: g_io_error_from_errno (err_no: errsv),
357 _("Error writing to file descriptor: %s"),
358 g_strerror (errnum: 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 = write (fd: unix_stream->priv->fd, buf: buffer, n: count);
369 errsv = errno;
370 if (res == -1)
371 {
372 if (errsv == EINTR || errsv == EAGAIN)
373 continue;
374
375 g_set_error (err: error, G_IO_ERROR,
376 code: g_io_error_from_errno (err_no: errsv),
377 _("Error writing to file descriptor: %s"),
378 g_strerror (errnum: errsv));
379 }
380
381 break;
382 }
383
384 if (nfds == 2)
385 g_cancellable_release_fd (cancellable);
386 return res;
387}
388
389/* Macro to check if struct iovec and GOutputVector have the same ABI */
390#define G_OUTPUT_VECTOR_IS_IOVEC (sizeof (struct iovec) == sizeof (GOutputVector) && \
391 G_SIZEOF_MEMBER (struct iovec, iov_base) == G_SIZEOF_MEMBER (GOutputVector, buffer) && \
392 G_STRUCT_OFFSET (struct iovec, iov_base) == G_STRUCT_OFFSET (GOutputVector, buffer) && \
393 G_SIZEOF_MEMBER (struct iovec, iov_len) == G_SIZEOF_MEMBER (GOutputVector, size) && \
394 G_STRUCT_OFFSET (struct iovec, iov_len) == G_STRUCT_OFFSET (GOutputVector, size))
395
396static gboolean
397g_unix_output_stream_writev (GOutputStream *stream,
398 const GOutputVector *vectors,
399 gsize n_vectors,
400 gsize *bytes_written,
401 GCancellable *cancellable,
402 GError **error)
403{
404 GUnixOutputStream *unix_stream;
405 gssize res = -1;
406 GPollFD poll_fds[2];
407 int nfds = 0;
408 int poll_ret;
409 struct iovec *iov;
410
411 if (bytes_written)
412 *bytes_written = 0;
413
414 /* Clamp the number of vectors if more given than we can write in one go.
415 * The caller has to handle short writes anyway.
416 */
417 if (n_vectors > G_IOV_MAX)
418 n_vectors = G_IOV_MAX;
419
420 unix_stream = G_UNIX_OUTPUT_STREAM (stream);
421
422 if (G_OUTPUT_VECTOR_IS_IOVEC)
423 {
424 /* ABI is compatible */
425 iov = (struct iovec *) vectors;
426 }
427 else
428 {
429 gsize i;
430
431 /* ABI is incompatible */
432 iov = g_newa (struct iovec, n_vectors);
433 for (i = 0; i < n_vectors; i++)
434 {
435 iov[i].iov_base = (void *)vectors[i].buffer;
436 iov[i].iov_len = vectors[i].size;
437 }
438 }
439
440 poll_fds[0].fd = unix_stream->priv->fd;
441 poll_fds[0].events = G_IO_OUT;
442 nfds++;
443
444 if (unix_stream->priv->can_poll &&
445 g_cancellable_make_pollfd (cancellable, pollfd: &poll_fds[1]))
446 nfds++;
447
448 while (1)
449 {
450 int errsv;
451
452 poll_fds[0].revents = poll_fds[1].revents = 0;
453 do
454 {
455 poll_ret = g_poll (fds: poll_fds, nfds, timeout: -1);
456 errsv = errno;
457 }
458 while (poll_ret == -1 && errsv == EINTR);
459
460 if (poll_ret == -1)
461 {
462 g_set_error (err: error, G_IO_ERROR,
463 code: g_io_error_from_errno (err_no: errsv),
464 _("Error writing to file descriptor: %s"),
465 g_strerror (errnum: errsv));
466 break;
467 }
468
469 if (g_cancellable_set_error_if_cancelled (cancellable, error))
470 break;
471
472 if (!poll_fds[0].revents)
473 continue;
474
475 res = writev (fd: unix_stream->priv->fd, iovec: iov, count: n_vectors);
476 errsv = errno;
477 if (res == -1)
478 {
479 if (errsv == EINTR || errsv == EAGAIN)
480 continue;
481
482 g_set_error (err: error, G_IO_ERROR,
483 code: g_io_error_from_errno (err_no: errsv),
484 _("Error writing to file descriptor: %s"),
485 g_strerror (errnum: errsv));
486 }
487
488 if (bytes_written)
489 *bytes_written = res;
490
491 break;
492 }
493
494 if (nfds == 2)
495 g_cancellable_release_fd (cancellable);
496 return res != -1;
497}
498
499static gboolean
500g_unix_output_stream_close (GOutputStream *stream,
501 GCancellable *cancellable,
502 GError **error)
503{
504 GUnixOutputStream *unix_stream;
505 int res;
506
507 unix_stream = G_UNIX_OUTPUT_STREAM (stream);
508
509 if (!unix_stream->priv->close_fd)
510 return TRUE;
511
512 /* This might block during the close. Doesn't seem to be a way to avoid it though. */
513 res = close (fd: unix_stream->priv->fd);
514 if (res == -1)
515 {
516 int errsv = errno;
517
518 g_set_error (err: error, G_IO_ERROR,
519 code: g_io_error_from_errno (err_no: errsv),
520 _("Error closing file descriptor: %s"),
521 g_strerror (errnum: errsv));
522 }
523
524 return res != -1;
525}
526
527static gboolean
528g_unix_output_stream_pollable_can_poll (GPollableOutputStream *stream)
529{
530 return G_UNIX_OUTPUT_STREAM (stream)->priv->can_poll;
531}
532
533static gboolean
534g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream)
535{
536 GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
537 GPollFD poll_fd;
538 gint result;
539
540 poll_fd.fd = unix_stream->priv->fd;
541 poll_fd.events = G_IO_OUT;
542 poll_fd.revents = 0;
543
544 do
545 result = g_poll (fds: &poll_fd, nfds: 1, timeout: 0);
546 while (result == -1 && errno == EINTR);
547
548 return poll_fd.revents != 0;
549}
550
551static GSource *
552g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
553 GCancellable *cancellable)
554{
555 GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
556 GSource *inner_source, *cancellable_source, *pollable_source;
557
558 pollable_source = g_pollable_source_new (G_OBJECT (stream));
559
560 inner_source = g_unix_fd_source_new (fd: unix_stream->priv->fd, condition: G_IO_OUT);
561 g_source_set_dummy_callback (source: inner_source);
562 g_source_add_child_source (source: pollable_source, child_source: inner_source);
563 g_source_unref (source: inner_source);
564
565 if (cancellable)
566 {
567 cancellable_source = g_cancellable_source_new (cancellable);
568 g_source_set_dummy_callback (source: cancellable_source);
569 g_source_add_child_source (source: pollable_source, child_source: cancellable_source);
570 g_source_unref (source: cancellable_source);
571 }
572
573 return pollable_source;
574}
575
576static GPollableReturn
577g_unix_output_stream_pollable_writev_nonblocking (GPollableOutputStream *stream,
578 const GOutputVector *vectors,
579 gsize n_vectors,
580 gsize *bytes_written,
581 GError **error)
582{
583 GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
584 struct iovec *iov;
585 gssize res = -1;
586
587 if (!g_pollable_output_stream_is_writable (stream))
588 {
589 *bytes_written = 0;
590 return G_POLLABLE_RETURN_WOULD_BLOCK;
591 }
592
593 /* Clamp the number of vectors if more given than we can write in one go.
594 * The caller has to handle short writes anyway.
595 */
596 if (n_vectors > G_IOV_MAX)
597 n_vectors = G_IOV_MAX;
598
599 if (G_OUTPUT_VECTOR_IS_IOVEC)
600 {
601 /* ABI is compatible */
602 iov = (struct iovec *) vectors;
603 }
604 else
605 {
606 gsize i;
607
608 /* ABI is incompatible */
609 iov = g_newa (struct iovec, n_vectors);
610 for (i = 0; i < n_vectors; i++)
611 {
612 iov[i].iov_base = (void *)vectors[i].buffer;
613 iov[i].iov_len = vectors[i].size;
614 }
615 }
616
617 while (1)
618 {
619 int errsv;
620
621 res = writev (fd: unix_stream->priv->fd, iovec: iov, count: n_vectors);
622 errsv = errno;
623 if (res == -1)
624 {
625 if (errsv == EINTR)
626 continue;
627
628 g_set_error (err: error, G_IO_ERROR,
629 code: g_io_error_from_errno (err_no: errsv),
630 _("Error writing to file descriptor: %s"),
631 g_strerror (errnum: errsv));
632 }
633
634 if (bytes_written)
635 *bytes_written = res;
636
637 break;
638 }
639
640 return res != -1 ? G_POLLABLE_RETURN_OK : G_POLLABLE_RETURN_FAILED;
641}
642

source code of gtk/subprojects/glib/gio/gunixoutputstream.c