qemu/io/channel-buffer.c

   1 /*
   2  * QEMU I/O channels memory buffer driver
   3  *
   4  * Copyright (c) 2015 Red Hat, Inc.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "io/channel-buffer.h"
  23 #include "io/channel-watch.h"
  24 #include "qemu/sockets.h"
  25 #include "trace.h"
  26
  27 QIOChannelBuffer *
  28 qio_channel_buffer_new(size_t capacity)
  29 {
  30     QIOChannelBuffer *ioc;
  31
  32     ioc = QIO_CHANNEL_BUFFER(object_new(TYPE_QIO_CHANNEL_BUFFER));
  33
  34     if (capacity) {
  35         ioc->data = g_new0(uint8_t, capacity);
  36         ioc->capacity = capacity;
  37     }
  38
  39     return ioc;
  40 }
  41
  42
  43 static void qio_channel_buffer_finalize(Object *obj)
  44 {
  45     QIOChannelBuffer *ioc = QIO_CHANNEL_BUFFER(obj);
  46     g_free(ioc->data);
  47     ioc->capacity = ioc->usage = ioc->offset = 0;
  48 }
  49
  50
  51 static ssize_t qio_channel_buffer_readv(QIOChannel *ioc,
  52                                         const struct iovec *iov,
  53                                         size_t niov,
  54                                         int **fds,
  55                                         size_t *nfds,
  56                                         Error **errp)
  57 {
  58     QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
  59     ssize_t ret = 0;
  60     size_t i;
  61
  62     for (i = 0; i < niov; i++) {
  63         size_t want = iov[i].iov_len;
  64         if (bioc->offset >= bioc->usage) {
  65             break;
  66         }
  67         if ((bioc->offset + want) > bioc->usage)  {
  68             want = bioc->usage - bioc->offset;
  69         }
  70         memcpy(iov[i].iov_base, bioc->data + bioc->offset, want);
  71         ret += want;
  72         bioc->offset += want;
  73     }
  74
  75     return ret;
  76 }
  77
  78 static ssize_t qio_channel_buffer_writev(QIOChannel *ioc,
  79                                          const struct iovec *iov,
  80                                          size_t niov,
  81                                          int *fds,
  82                                          size_t nfds,
  83                                          Error **errp)
  84 {
  85     QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
  86     ssize_t ret = 0;
  87     size_t i;
  88     size_t towrite = 0;
  89
  90     for (i = 0; i < niov; i++) {
  91         towrite += iov[i].iov_len;
  92     }
  93
  94     if ((bioc->offset + towrite) > bioc->capacity) {
  95         bioc->capacity = bioc->offset + towrite;
  96         bioc->data = g_realloc(bioc->data, bioc->capacity);
  97     }
  98
  99     if (bioc->offset > bioc->usage) {
 100         memset(bioc->data, 0, bioc->offset - bioc->usage);
 101         bioc->usage = bioc->offset;
 102     }
 103
 104     for (i = 0; i < niov; i++) {
 105         memcpy(bioc->data + bioc->usage,
 106                iov[i].iov_base,
 107                iov[i].iov_len);
 108         bioc->usage += iov[i].iov_len;
 109         bioc->offset += iov[i].iov_len;
 110         ret += iov[i].iov_len;
 111     }
 112
 113     return ret;
 114 }
 115
 116 static int qio_channel_buffer_set_blocking(QIOChannel *ioc G_GNUC_UNUSED,
 117                                            bool enabled G_GNUC_UNUSED,
 118                                            Error **errp G_GNUC_UNUSED)
 119 {
 120     return 0;
 121 }
 122
 123
 124 static off_t qio_channel_buffer_seek(QIOChannel *ioc,
 125                                      off_t offset,
 126                                      int whence,
 127                                      Error **errp)
 128 {
 129     QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
 130
 131     bioc->offset = offset;
 132
 133     return offset;
 134 }
 135
 136
 137 static int qio_channel_buffer_close(QIOChannel *ioc,
 138                                     Error **errp)
 139 {
 140     QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
 141
 142     g_free(bioc->data);
 143     bioc->capacity = bioc->usage = bioc->offset = 0;
 144
 145     return 0;
 146 }
 147
 148
 149 typedef struct QIOChannelBufferSource QIOChannelBufferSource;
 150 struct QIOChannelBufferSource {
 151     GSource parent;
 152     QIOChannelBuffer *bioc;
 153     GIOCondition condition;
 154 };
 155
 156 static gboolean
 157 qio_channel_buffer_source_prepare(GSource *source,
 158                                   gint *timeout)
 159 {
 160     QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
 161
 162     *timeout = -1;
 163
 164     return (G_IO_IN | G_IO_OUT) & bsource->condition;
 165 }
 166
 167 static gboolean
 168 qio_channel_buffer_source_check(GSource *source)
 169 {
 170     QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
 171
 172     return (G_IO_IN | G_IO_OUT) & bsource->condition;
 173 }
 174
 175 static gboolean
 176 qio_channel_buffer_source_dispatch(GSource *source,
 177                                    GSourceFunc callback,
 178                                    gpointer user_data)
 179 {
 180     QIOChannelFunc func = (QIOChannelFunc)callback;
 181     QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
 182
 183     return (*func)(QIO_CHANNEL(bsource->bioc),
 184                    ((G_IO_IN | G_IO_OUT) & bsource->condition),
 185                    user_data);
 186 }
 187
 188 static void
 189 qio_channel_buffer_source_finalize(GSource *source)
 190 {
 191     QIOChannelBufferSource *ssource = (QIOChannelBufferSource *)source;
 192
 193     object_unref(OBJECT(ssource->bioc));
 194 }
 195
 196 GSourceFuncs qio_channel_buffer_source_funcs = {
 197     qio_channel_buffer_source_prepare,
 198     qio_channel_buffer_source_check,
 199     qio_channel_buffer_source_dispatch,
 200     qio_channel_buffer_source_finalize
 201 };
 202
 203 static GSource *qio_channel_buffer_create_watch(QIOChannel *ioc,
 204                                                 GIOCondition condition)
 205 {
 206     QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
 207     QIOChannelBufferSource *ssource;
 208     GSource *source;
 209
 210     source = g_source_new(&qio_channel_buffer_source_funcs,
 211                           sizeof(QIOChannelBufferSource));
 212     ssource = (QIOChannelBufferSource *)source;
 213
 214     ssource->bioc = bioc;
 215     object_ref(OBJECT(bioc));
 216
 217     ssource->condition = condition;
 218
 219     return source;
 220 }
 221
 222
 223 static void qio_channel_buffer_class_init(ObjectClass *klass,
 224                                           void *class_data G_GNUC_UNUSED)
 225 {
 226     QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
 227
 228     ioc_klass->io_writev = qio_channel_buffer_writev;
 229     ioc_klass->io_readv = qio_channel_buffer_readv;
 230     ioc_klass->io_set_blocking = qio_channel_buffer_set_blocking;
 231     ioc_klass->io_seek = qio_channel_buffer_seek;
 232     ioc_klass->io_close = qio_channel_buffer_close;
 233     ioc_klass->io_create_watch = qio_channel_buffer_create_watch;
 234 }
 235
 236 static const TypeInfo qio_channel_buffer_info = {
 237     .parent = TYPE_QIO_CHANNEL,
 238     .name = TYPE_QIO_CHANNEL_BUFFER,
 239     .instance_size = sizeof(QIOChannelBuffer),
 240     .instance_finalize = qio_channel_buffer_finalize,
 241     .class_init = qio_channel_buffer_class_init,
 242 };
 243
 244 static void qio_channel_buffer_register_types(void)
 245 {
 246     type_register_static(&qio_channel_buffer_info);
 247 }
 248
 249 type_init(qio_channel_buffer_register_types);