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glib/gio/gunixoutputstream.c
Sebastian Dröge 20a2c379c4 Clamp number of vectors to IOV_MAX / UIO_MAXIOV for GOutputStream writev() calls in the implementations 
More vectors will give an error and we can simply clamp here and
consider it like a short write instead.

In case of GSocketOutputStream this is done here instead of inside
GSocket before calling sendmsg() because we we can't generically handle
short writes when sending messages on a socket, e.g. for datagram
sockets this causes only part of the datagram to be sent and an error
would be more useful in this case than sending corrupted data.

Also reduce the fallback limit to 16 in gsocket.c as that's the minimum
value required by POSIX and add a static assertion that the limit is
never bigger than G_MAXINT as that's the type recvmmsg/sendmmsg take.
2019-05-31 12:51:59 +03:00

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/* GIO - GLib Input, Output and Streaming Library
*
* Copyright (C) 2006-2007 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
* Author: Alexander Larsson <alexl@redhat.com>
*/
#include "config.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/uio.h>
#include <glib.h>
#include <glib/gstdio.h>
#include <glib/glib-unix.h>
#include "gioerror.h"
#include "gunixoutputstream.h"
#include "gcancellable.h"
#include "gasynchelper.h"
#include "gfiledescriptorbased.h"
#include "glibintl.h"
#include "gioprivate.h"
/**
* SECTION:gunixoutputstream
* @short_description: Streaming output operations for UNIX file descriptors
* @include: gio/gunixoutputstream.h
* @see_also: #GOutputStream
*
* #GUnixOutputStream implements #GOutputStream for writing to a UNIX
* file descriptor, including asynchronous operations. (If the file
* descriptor refers to a socket or pipe, this will use poll() to do
* asynchronous I/O. If it refers to a regular file, it will fall back
* to doing asynchronous I/O in another thread.)
*
* Note that `<gio/gunixoutputstream.h>` belongs to the UNIX-specific GIO
* interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config file
* when using it.
*/
enum {
PROP_0,
PROP_FD,
PROP_CLOSE_FD
};
struct _GUnixOutputStreamPrivate {
int fd;
guint close_fd : 1;
guint is_pipe_or_socket : 1;
};
static void g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface);
static void g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);
G_DEFINE_TYPE_WITH_CODE (GUnixOutputStream, g_unix_output_stream, G_TYPE_OUTPUT_STREAM,
G_ADD_PRIVATE (GUnixOutputStream)
G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_OUTPUT_STREAM,
g_unix_output_stream_pollable_iface_init)
G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
g_unix_output_stream_file_descriptor_based_iface_init)
)
static void g_unix_output_stream_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec);
static void g_unix_output_stream_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec);
static gssize g_unix_output_stream_write (GOutputStream *stream,
const void *buffer,
gsize count,
GCancellable *cancellable,
GError **error);
static gboolean g_unix_output_stream_writev (GOutputStream *stream,
const GOutputVector *vectors,
gsize n_vectors,
gsize *bytes_written,
GCancellable *cancellable,
GError **error);
static gboolean g_unix_output_stream_close (GOutputStream *stream,
GCancellable *cancellable,
GError **error);
static void g_unix_output_stream_close_async (GOutputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer data);
static gboolean g_unix_output_stream_close_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error);
static gboolean g_unix_output_stream_pollable_can_poll (GPollableOutputStream *stream);
static gboolean g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream);
static GSource *g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
GCancellable *cancellable);
static GPollableReturn g_unix_output_stream_pollable_writev_nonblocking (GPollableOutputStream *stream,
const GOutputVector *vectors,
gsize n_vectors,
gsize *bytes_written,
GError **error);
static void
g_unix_output_stream_class_init (GUnixOutputStreamClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
GOutputStreamClass *stream_class = G_OUTPUT_STREAM_CLASS (klass);
gobject_class->get_property = g_unix_output_stream_get_property;
gobject_class->set_property = g_unix_output_stream_set_property;
stream_class->write_fn = g_unix_output_stream_write;
stream_class->writev_fn = g_unix_output_stream_writev;
stream_class->close_fn = g_unix_output_stream_close;
stream_class->close_async = g_unix_output_stream_close_async;
stream_class->close_finish = g_unix_output_stream_close_finish;
/**
* GUnixOutputStream:fd:
*
* The file descriptor that the stream writes to.
*
* Since: 2.20
*/
g_object_class_install_property (gobject_class,
PROP_FD,
g_param_spec_int ("fd",
P_("File descriptor"),
P_("The file descriptor to write to"),
G_MININT, G_MAXINT, -1,
G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
/**
* GUnixOutputStream:close-fd:
*
* Whether to close the file descriptor when the stream is closed.
*
* Since: 2.20
*/
g_object_class_install_property (gobject_class,
PROP_CLOSE_FD,
g_param_spec_boolean ("close-fd",
P_("Close file descriptor"),
P_("Whether to close the file descriptor when the stream is closed"),
TRUE,
G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
}
static void
g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface)
{
iface->can_poll = g_unix_output_stream_pollable_can_poll;
iface->is_writable = g_unix_output_stream_pollable_is_writable;
iface->create_source = g_unix_output_stream_pollable_create_source;
iface->writev_nonblocking = g_unix_output_stream_pollable_writev_nonblocking;
}
static void
g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
{
iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_output_stream_get_fd;
}
static void
g_unix_output_stream_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GUnixOutputStream *unix_stream;
unix_stream = G_UNIX_OUTPUT_STREAM (object);
switch (prop_id)
{
case PROP_FD:
unix_stream->priv->fd = g_value_get_int (value);
if (lseek (unix_stream->priv->fd, 0, SEEK_CUR) == -1 && errno == ESPIPE)
unix_stream->priv->is_pipe_or_socket = TRUE;
else
unix_stream->priv->is_pipe_or_socket = FALSE;
break;
case PROP_CLOSE_FD:
unix_stream->priv->close_fd = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
g_unix_output_stream_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GUnixOutputStream *unix_stream;
unix_stream = G_UNIX_OUTPUT_STREAM (object);
switch (prop_id)
{
case PROP_FD:
g_value_set_int (value, unix_stream->priv->fd);
break;
case PROP_CLOSE_FD:
g_value_set_boolean (value, unix_stream->priv->close_fd);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
}
}
static void
g_unix_output_stream_init (GUnixOutputStream *unix_stream)
{
unix_stream->priv = g_unix_output_stream_get_instance_private (unix_stream);
unix_stream->priv->fd = -1;
unix_stream->priv->close_fd = TRUE;
}
/**
* g_unix_output_stream_new:
* @fd: a UNIX file descriptor
* @close_fd: %TRUE to close the file descriptor when done
*
* Creates a new #GUnixOutputStream for the given @fd.
*
* If @close_fd, is %TRUE, the file descriptor will be closed when
* the output stream is destroyed.
*
* Returns: a new #GOutputStream
**/
GOutputStream *
g_unix_output_stream_new (gint fd,
gboolean close_fd)
{
GUnixOutputStream *stream;
g_return_val_if_fail (fd != -1, NULL);
stream = g_object_new (G_TYPE_UNIX_OUTPUT_STREAM,
"fd", fd,
"close-fd", close_fd,
NULL);
return G_OUTPUT_STREAM (stream);
}
/**
* g_unix_output_stream_set_close_fd:
* @stream: a #GUnixOutputStream
* @close_fd: %TRUE to close the file descriptor when done
*
* Sets whether the file descriptor of @stream shall be closed
* when the stream is closed.
*
* Since: 2.20
*/
void
g_unix_output_stream_set_close_fd (GUnixOutputStream *stream,
gboolean close_fd)
{
g_return_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream));
close_fd = close_fd != FALSE;
if (stream->priv->close_fd != close_fd)
{
stream->priv->close_fd = close_fd;
g_object_notify (G_OBJECT (stream), "close-fd");
}
}
/**
* g_unix_output_stream_get_close_fd:
* @stream: a #GUnixOutputStream
*
* Returns whether the file descriptor of @stream will be
* closed when the stream is closed.
*
* Returns: %TRUE if the file descriptor is closed when done
*
* Since: 2.20
*/
gboolean
g_unix_output_stream_get_close_fd (GUnixOutputStream *stream)
{
g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), FALSE);
return stream->priv->close_fd;
}
/**
* g_unix_output_stream_get_fd:
* @stream: a #GUnixOutputStream
*
* Return the UNIX file descriptor that the stream writes to.
*
* Returns: The file descriptor of @stream
*
* Since: 2.20
*/
gint
g_unix_output_stream_get_fd (GUnixOutputStream *stream)
{
g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), -1);
return stream->priv->fd;
}
static gssize
g_unix_output_stream_write (GOutputStream *stream,
const void *buffer,
gsize count,
GCancellable *cancellable,
GError **error)
{
GUnixOutputStream *unix_stream;
gssize res = -1;
GPollFD poll_fds[2];
int nfds = 0;
int poll_ret;
unix_stream = G_UNIX_OUTPUT_STREAM (stream);
poll_fds[0].fd = unix_stream->priv->fd;
poll_fds[0].events = G_IO_OUT;
nfds++;
if (unix_stream->priv->is_pipe_or_socket &&
g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
nfds++;
while (1)
{
int errsv;
poll_fds[0].revents = poll_fds[1].revents = 0;
do
{
poll_ret = g_poll (poll_fds, nfds, -1);
errsv = errno;
}
while (poll_ret == -1 && errsv == EINTR);
if (poll_ret == -1)
{
g_set_error (error, G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error writing to file descriptor: %s"),
g_strerror (errsv));
break;
}
if (g_cancellable_set_error_if_cancelled (cancellable, error))
break;
if (!poll_fds[0].revents)
continue;
res = write (unix_stream->priv->fd, buffer, count);
errsv = errno;
if (res == -1)
{
if (errsv == EINTR || errsv == EAGAIN)
continue;
g_set_error (error, G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error writing to file descriptor: %s"),
g_strerror (errsv));
}
break;
}
if (nfds == 2)
g_cancellable_release_fd (cancellable);
return res;
}
/* Macro to check if struct iovec and GOutputVector have the same ABI */
#define G_OUTPUT_VECTOR_IS_IOVEC (sizeof (struct iovec) == sizeof (GOutputVector) && \
sizeof ((struct iovec *) 0)->iov_base == sizeof ((GOutputVector *) 0)->buffer && \
G_STRUCT_OFFSET (struct iovec, iov_base) == G_STRUCT_OFFSET (GOutputVector, buffer) && \
sizeof ((struct iovec *) 0)->iov_len == sizeof((GOutputVector *) 0)->size && \
G_STRUCT_OFFSET (struct iovec, iov_len) == G_STRUCT_OFFSET (GOutputVector, size))
static gboolean
g_unix_output_stream_writev (GOutputStream *stream,
const GOutputVector *vectors,
gsize n_vectors,
gsize *bytes_written,
GCancellable *cancellable,
GError **error)
{
GUnixOutputStream *unix_stream;
gssize res = -1;
GPollFD poll_fds[2];
int nfds = 0;
int poll_ret;
struct iovec *iov;
if (bytes_written)
*bytes_written = 0;
/* Clamp the number of vectors if more given than we can write in one go.
* The caller has to handle short writes anyway.
*/
if (n_vectors > G_IOV_MAX)
n_vectors = G_IOV_MAX;
unix_stream = G_UNIX_OUTPUT_STREAM (stream);
if (G_OUTPUT_VECTOR_IS_IOVEC)
{
/* ABI is compatible */
iov = (struct iovec *) vectors;
}
else
{
gsize i;
/* ABI is incompatible */
iov = g_newa (struct iovec, n_vectors);
for (i = 0; i < n_vectors; i++)
{
iov[i].iov_base = (void *)vectors[i].buffer;
iov[i].iov_len = vectors[i].size;
}
}
poll_fds[0].fd = unix_stream->priv->fd;
poll_fds[0].events = G_IO_OUT;
nfds++;
if (unix_stream->priv->is_pipe_or_socket &&
g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
nfds++;
while (1)
{
int errsv;
poll_fds[0].revents = poll_fds[1].revents = 0;
do
{
poll_ret = g_poll (poll_fds, nfds, -1);
errsv = errno;
}
while (poll_ret == -1 && errsv == EINTR);
if (poll_ret == -1)
{
g_set_error (error, G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error writing to file descriptor: %s"),
g_strerror (errsv));
break;
}
if (g_cancellable_set_error_if_cancelled (cancellable, error))
break;
if (!poll_fds[0].revents)
continue;
res = writev (unix_stream->priv->fd, iov, n_vectors);
errsv = errno;
if (res == -1)
{
if (errsv == EINTR || errsv == EAGAIN)
continue;
g_set_error (error, G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error writing to file descriptor: %s"),
g_strerror (errsv));
}
if (bytes_written)
*bytes_written = res;
break;
}
if (nfds == 2)
g_cancellable_release_fd (cancellable);
return res != -1;
}
static gboolean
g_unix_output_stream_close (GOutputStream *stream,
GCancellable *cancellable,
GError **error)
{
GUnixOutputStream *unix_stream;
int res;
unix_stream = G_UNIX_OUTPUT_STREAM (stream);
if (!unix_stream->priv->close_fd)
return TRUE;
/* This might block during the close. Doesn't seem to be a way to avoid it though. */
res = close (unix_stream->priv->fd);
if (res == -1)
{
int errsv = errno;
g_set_error (error, G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error closing file descriptor: %s"),
g_strerror (errsv));
}
return res != -1;
}
static void
g_unix_output_stream_close_async (GOutputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GTask *task;
GError *error = NULL;
task = g_task_new (stream, cancellable, callback, user_data);
g_task_set_source_tag (task, g_unix_output_stream_close_async);
g_task_set_priority (task, io_priority);
if (g_unix_output_stream_close (stream, cancellable, &error))
g_task_return_boolean (task, TRUE);
else
g_task_return_error (task, error);
g_object_unref (task);
}
static gboolean
g_unix_output_stream_close_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error)
{
g_return_val_if_fail (g_task_is_valid (result, stream), FALSE);
return g_task_propagate_boolean (G_TASK (result), error);
}
static gboolean
g_unix_output_stream_pollable_can_poll (GPollableOutputStream *stream)
{
return G_UNIX_OUTPUT_STREAM (stream)->priv->is_pipe_or_socket;
}
static gboolean
g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream)
{
GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
GPollFD poll_fd;
gint result;
poll_fd.fd = unix_stream->priv->fd;
poll_fd.events = G_IO_OUT;
poll_fd.revents = 0;
do
result = g_poll (&poll_fd, 1, 0);
while (result == -1 && errno == EINTR);
return poll_fd.revents != 0;
}
static GSource *
g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
GCancellable *cancellable)
{
GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
GSource *inner_source, *cancellable_source, *pollable_source;
pollable_source = g_pollable_source_new (G_OBJECT (stream));
inner_source = g_unix_fd_source_new (unix_stream->priv->fd, G_IO_OUT);
g_source_set_dummy_callback (inner_source);
g_source_add_child_source (pollable_source, inner_source);
g_source_unref (inner_source);
if (cancellable)
{
cancellable_source = g_cancellable_source_new (cancellable);
g_source_set_dummy_callback (cancellable_source);
g_source_add_child_source (pollable_source, cancellable_source);
g_source_unref (cancellable_source);
}
return pollable_source;
}
static GPollableReturn
g_unix_output_stream_pollable_writev_nonblocking (GPollableOutputStream *stream,
const GOutputVector *vectors,
gsize n_vectors,
gsize *bytes_written,
GError **error)
{
GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
struct iovec *iov;
gssize res = -1;
if (!g_pollable_output_stream_is_writable (stream))
{
*bytes_written = 0;
return G_POLLABLE_RETURN_WOULD_BLOCK;
}
/* Clamp the number of vectors if more given than we can write in one go.
* The caller has to handle short writes anyway.
*/
if (n_vectors > G_IOV_MAX)
n_vectors = G_IOV_MAX;
if (G_OUTPUT_VECTOR_IS_IOVEC)
{
/* ABI is compatible */
iov = (struct iovec *) vectors;
}
else
{
gsize i;
/* ABI is incompatible */
iov = g_newa (struct iovec, n_vectors);
for (i = 0; i < n_vectors; i++)
{
iov[i].iov_base = (void *)vectors[i].buffer;
iov[i].iov_len = vectors[i].size;
}
}
while (1)
{
int errsv;
res = writev (unix_stream->priv->fd, iov, n_vectors);
errsv = errno;
if (res == -1)
{
if (errsv == EINTR)
continue;
g_set_error (error, G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error writing to file descriptor: %s"),
g_strerror (errsv));
}
if (bytes_written)
*bytes_written = res;
break;
}
return res != -1 ? G_POLLABLE_RETURN_OK : G_POLLABLE_RETURN_FAILED;
}
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