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authorDaniel P. Berrange <berrange@redhat.com>2015-09-15 17:27:33 +0100
committerDaniel P. Berrange <berrange@redhat.com>2015-12-18 12:18:31 +0000
commitd98e4eb7de93290f7921b0dbe869c7dd3c567945 (patch)
tree3f9d266d76b202a93b1bf7fd8a47affa4d521308 /io
parent195e14d0262c5676cb9ff4b253e4b2b15c19d3f0 (diff)
downloadqemu-arm-d98e4eb7de93290f7921b0dbe869c7dd3c567945.tar.gz
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>
Diffstat (limited to 'io')
-rw-r--r--io/Makefile.objs1
-rw-r--r--io/channel-buffer.c248
2 files changed, 249 insertions, 0 deletions
diff --git a/io/Makefile.objs b/io/Makefile.objs
index 1a58ccb5c2..0e3de31a5a 100644
--- a/io/Makefile.objs
+++ b/io/Makefile.objs
@@ -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
diff --git a/io/channel-buffer.c b/io/channel-buffer.c
new file mode 100644
index 0000000000..daebc92bd8
--- /dev/null
+++ b/io/channel-buffer.c
@@ -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);