qemu

channel-buffer.c (7190B)

---

 /*
  * 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 2.1 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/>.
  *
  */
 
 #include "qemu/osdep.h"
 #include "io/channel-buffer.h"
 #include "io/channel-watch.h"
 #include "qemu/module.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(uint8_t, 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,
                                          int flags,
                                          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->data = NULL;
     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);