io: add QIOChannelBuffer class

Add a QIOChannel subclass that is capable of performing I/O
to/from a memory buffer. This implementation does not attempt
to support concurrent readers & writers. It is designed for
serialized access where by a single thread at a time may write
data, seek and then read data back out.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This commit is contained in:
Daniel P. Berrange 2015-09-15 17:27:33 +01:00
parent 195e14d026
commit d98e4eb7de
6 changed files with 363 additions and 0 deletions

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@ -0,0 +1,60 @@
/*
* QEMU I/O channels memory buffer driver
*
* Copyright (c) 2015 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 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/>.
*
*/
#ifndef QIO_CHANNEL_BUFFER_H__
#define QIO_CHANNEL_BUFFER_H__
#include "io/channel.h"
#define TYPE_QIO_CHANNEL_BUFFER "qio-channel-buffer"
#define QIO_CHANNEL_BUFFER(obj) \
OBJECT_CHECK(QIOChannelBuffer, (obj), TYPE_QIO_CHANNEL_BUFFER)
typedef struct QIOChannelBuffer QIOChannelBuffer;
/**
* QIOChannelBuffer:
*
* The QIOChannelBuffer object provides a channel implementation
* that is able to perform I/O to/from a memory buffer.
*
*/
struct QIOChannelBuffer {
QIOChannel parent;
size_t capacity; /* Total allocated memory */
size_t usage; /* Current size of data */
size_t offset; /* Offset for future I/O ops */
char *data;
};
/**
* qio_channel_buffer_new:
* @capacity: the initial buffer capacity to allocate
*
* Allocate a new buffer which is initially empty
*
* Returns: the new channel object
*/
QIOChannelBuffer *
qio_channel_buffer_new(size_t capacity);
#endif /* QIO_CHANNEL_BUFFER_H__ */

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@ -1,4 +1,5 @@
io-obj-y = channel.o
io-obj-y += channel-buffer.o
io-obj-y += channel-command.o
io-obj-y += channel-file.o
io-obj-y += channel-socket.o

248
io/channel-buffer.c Normal file
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@ -0,0 +1,248 @@
/*
* QEMU I/O channels memory buffer driver
*
* Copyright (c) 2015 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 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/>.
*
*/
#include "io/channel-buffer.h"
#include "io/channel-watch.h"
#include "qemu/sockets.h"
#include "trace.h"
QIOChannelBuffer *
qio_channel_buffer_new(size_t capacity)
{
QIOChannelBuffer *ioc;
ioc = QIO_CHANNEL_BUFFER(object_new(TYPE_QIO_CHANNEL_BUFFER));
if (capacity) {
ioc->data = g_new0(char, capacity);
ioc->capacity = capacity;
}
return ioc;
}
static void qio_channel_buffer_finalize(Object *obj)
{
QIOChannelBuffer *ioc = QIO_CHANNEL_BUFFER(obj);
g_free(ioc->data);
ioc->capacity = ioc->usage = ioc->offset = 0;
}
static ssize_t qio_channel_buffer_readv(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int **fds,
size_t *nfds,
Error **errp)
{
QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
ssize_t ret = 0;
size_t i;
for (i = 0; i < niov; i++) {
size_t want = iov[i].iov_len;
if (bioc->offset >= bioc->usage) {
break;
}
if ((bioc->offset + want) > bioc->usage) {
want = bioc->usage - bioc->offset;
}
memcpy(iov[i].iov_base, bioc->data + bioc->offset, want);
ret += want;
bioc->offset += want;
}
return ret;
}
static ssize_t qio_channel_buffer_writev(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int *fds,
size_t nfds,
Error **errp)
{
QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
ssize_t ret = 0;
size_t i;
size_t towrite = 0;
for (i = 0; i < niov; i++) {
towrite += iov[i].iov_len;
}
if ((bioc->offset + towrite) > bioc->capacity) {
bioc->capacity = bioc->offset + towrite;
bioc->data = g_realloc(bioc->data, bioc->capacity);
}
if (bioc->offset > bioc->usage) {
memset(bioc->data, 0, bioc->offset - bioc->usage);
bioc->usage = bioc->offset;
}
for (i = 0; i < niov; i++) {
memcpy(bioc->data + bioc->usage,
iov[i].iov_base,
iov[i].iov_len);
bioc->usage += iov[i].iov_len;
bioc->offset += iov[i].iov_len;
ret += iov[i].iov_len;
}
return ret;
}
static int qio_channel_buffer_set_blocking(QIOChannel *ioc G_GNUC_UNUSED,
bool enabled G_GNUC_UNUSED,
Error **errp G_GNUC_UNUSED)
{
return 0;
}
static off_t qio_channel_buffer_seek(QIOChannel *ioc,
off_t offset,
int whence,
Error **errp)
{
QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
bioc->offset = offset;
return offset;
}
static int qio_channel_buffer_close(QIOChannel *ioc,
Error **errp)
{
QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
g_free(bioc->data);
bioc->capacity = bioc->usage = bioc->offset = 0;
return 0;
}
typedef struct QIOChannelBufferSource QIOChannelBufferSource;
struct QIOChannelBufferSource {
GSource parent;
QIOChannelBuffer *bioc;
GIOCondition condition;
};
static gboolean
qio_channel_buffer_source_prepare(GSource *source,
gint *timeout)
{
QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
*timeout = -1;
return (G_IO_IN | G_IO_OUT) & bsource->condition;
}
static gboolean
qio_channel_buffer_source_check(GSource *source)
{
QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
return (G_IO_IN | G_IO_OUT) & bsource->condition;
}
static gboolean
qio_channel_buffer_source_dispatch(GSource *source,
GSourceFunc callback,
gpointer user_data)
{
QIOChannelFunc func = (QIOChannelFunc)callback;
QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
return (*func)(QIO_CHANNEL(bsource->bioc),
((G_IO_IN | G_IO_OUT) & bsource->condition),
user_data);
}
static void
qio_channel_buffer_source_finalize(GSource *source)
{
QIOChannelBufferSource *ssource = (QIOChannelBufferSource *)source;
object_unref(OBJECT(ssource->bioc));
}
GSourceFuncs qio_channel_buffer_source_funcs = {
qio_channel_buffer_source_prepare,
qio_channel_buffer_source_check,
qio_channel_buffer_source_dispatch,
qio_channel_buffer_source_finalize
};
static GSource *qio_channel_buffer_create_watch(QIOChannel *ioc,
GIOCondition condition)
{
QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
QIOChannelBufferSource *ssource;
GSource *source;
source = g_source_new(&qio_channel_buffer_source_funcs,
sizeof(QIOChannelBufferSource));
ssource = (QIOChannelBufferSource *)source;
ssource->bioc = bioc;
object_ref(OBJECT(bioc));
ssource->condition = condition;
return source;
}
static void qio_channel_buffer_class_init(ObjectClass *klass,
void *class_data G_GNUC_UNUSED)
{
QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
ioc_klass->io_writev = qio_channel_buffer_writev;
ioc_klass->io_readv = qio_channel_buffer_readv;
ioc_klass->io_set_blocking = qio_channel_buffer_set_blocking;
ioc_klass->io_seek = qio_channel_buffer_seek;
ioc_klass->io_close = qio_channel_buffer_close;
ioc_klass->io_create_watch = qio_channel_buffer_create_watch;
}
static const TypeInfo qio_channel_buffer_info = {
.parent = TYPE_QIO_CHANNEL,
.name = TYPE_QIO_CHANNEL_BUFFER,
.instance_size = sizeof(QIOChannelBuffer),
.instance_finalize = qio_channel_buffer_finalize,
.class_init = qio_channel_buffer_class_init,
};
static void qio_channel_buffer_register_types(void)
{
type_register_static(&qio_channel_buffer_info);
}
type_init(qio_channel_buffer_register_types);

1
tests/.gitignore vendored
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@ -24,6 +24,7 @@ test-cutils
test-hbitmap
test-int128
test-iov
test-io-channel-buffer
test-io-channel-command
test-io-channel-command.fifo
test-io-channel-file

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@ -89,6 +89,7 @@ check-unit-y += tests/test-io-channel-socket$(EXESUF)
check-unit-y += tests/test-io-channel-file$(EXESUF)
check-unit-$(CONFIG_GNUTLS) += tests/test-io-channel-tls$(EXESUF)
check-unit-y += tests/test-io-channel-command$(EXESUF)
check-unit-y += tests/test-io-channel-buffer$(EXESUF)
check-block-$(CONFIG_POSIX) += tests/qemu-iotests-quick.sh
@ -485,6 +486,8 @@ tests/test-io-channel-tls$(EXESUF): tests/test-io-channel-tls.o \
tests/io-channel-helpers.o $(test-io-obj-y)
tests/test-io-channel-command$(EXESUF): tests/test-io-channel-command.o \
tests/io-channel-helpers.o $(test-io-obj-y)
tests/test-io-channel-buffer$(EXESUF): tests/test-io-channel-buffer.o \
tests/io-channel-helpers.o $(test-io-obj-y)
libqos-obj-y = tests/libqos/pci.o tests/libqos/fw_cfg.o tests/libqos/malloc.o
libqos-obj-y += tests/libqos/i2c.o tests/libqos/libqos.o

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@ -0,0 +1,50 @@
/*
* QEMU I/O channel buffer test
*
* Copyright (c) 2015 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 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/>.
*
*/
#include "io/channel-buffer.h"
#include "io-channel-helpers.h"
static void test_io_channel_buf(void)
{
QIOChannelBuffer *buf;
QIOChannelTest *test;
buf = qio_channel_buffer_new(0);
test = qio_channel_test_new();
qio_channel_test_run_writer(test, QIO_CHANNEL(buf));
buf->offset = 0;
qio_channel_test_run_reader(test, QIO_CHANNEL(buf));
qio_channel_test_validate(test);
object_unref(OBJECT(buf));
}
int main(int argc, char **argv)
{
module_call_init(MODULE_INIT_QOM);
g_test_init(&argc, &argv, NULL);
g_test_add_func("/io/channel/buf", test_io_channel_buf);
return g_test_run();
}