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 2.1 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/module.h"
  25 #include "qemu/sockets.h"
  26 #include "trace.h"
  27
  28 QIOChannelBuffer *
  29 qio_channel_buffer_new(size_t capacity)
  30 {
  31     QIOChannelBuffer *ioc;
  32
  33     ioc = QIO_CHANNEL_BUFFER(object_new(TYPE_QIO_CHANNEL_BUFFER));
  34
  35     if (capacity) {
  36         ioc->data = g_new0(uint8_t, capacity);
  37         ioc->capacity = capacity;
  38     }
  39
  40     return ioc;
  41 }
  42
  43
  44 static void qio_channel_buffer_finalize(Object *obj)
  45 {
  46     QIOChannelBuffer *ioc = QIO_CHANNEL_BUFFER(obj);
  47     g_free(ioc->data);
  48     ioc->capacity = ioc->usage = ioc->offset = 0;
  49 }
  50
  51
  52 static ssize_t qio_channel_buffer_readv(QIOChannel *ioc,
  53                                         const struct iovec *iov,
  54                                         size_t niov,
  55                                         int **fds,
  56                                         size_t *nfds,
  57                                         int flags,
  58                                         Error **errp)
  59 {
  60     QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
  61     ssize_t ret = 0;
  62     size_t i;
  63
  64     for (i = 0; i < niov; i++) {
  65         size_t want = iov[i].iov_len;
  66         if (bioc->offset >= bioc->usage) {
  67             break;
  68         }
  69         if ((bioc->offset + want) > bioc->usage)  {
  70             want = bioc->usage - bioc->offset;
  71         }
  72         memcpy(iov[i].iov_base, bioc->data + bioc->offset, want);
  73         ret += want;
  74         bioc->offset += want;
  75     }
  76
  77     return ret;
  78 }
  79
  80 static ssize_t qio_channel_buffer_writev(QIOChannel *ioc,
  81                                          const struct iovec *iov,
  82                                          size_t niov,
  83                                          int *fds,
  84                                          size_t nfds,
  85                                          int flags,
  86                                          Error **errp)
  87 {
  88     QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
  89     ssize_t ret = 0;
  90     size_t i;
  91     size_t towrite = 0;
  92
  93     for (i = 0; i < niov; i++) {
  94         towrite += iov[i].iov_len;
  95     }
  96
  97     if ((bioc->offset + towrite) > bioc->capacity) {
  98         bioc->capacity = bioc->offset + towrite;
  99         bioc->data = g_realloc(bioc->data, bioc->capacity);
 100     }
 101
 102     if (bioc->offset > bioc->usage) {
 103         memset(bioc->data, 0, bioc->offset - bioc->usage);
 104         bioc->usage = bioc->offset;
 105     }
 106
 107     for (i = 0; i < niov; i++) {
 108         memcpy(bioc->data + bioc->usage,
 109                iov[i].iov_base,
 110                iov[i].iov_len);
 111         bioc->usage += iov[i].iov_len;
 112         bioc->offset += iov[i].iov_len;
 113         ret += iov[i].iov_len;
 114     }
 115
 116     return ret;
 117 }
 118
 119 static int qio_channel_buffer_set_blocking(QIOChannel *ioc G_GNUC_UNUSED,
 120                                            bool enabled G_GNUC_UNUSED,
 121                                            Error **errp G_GNUC_UNUSED)
 122 {
 123     return 0;
 124 }
 125
 126
 127 static off_t qio_channel_buffer_seek(QIOChannel *ioc,
 128                                      off_t offset,
 129                                      int whence,
 130                                      Error **errp)
 131 {
 132     QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
 133
 134     bioc->offset = offset;
 135
 136     return offset;
 137 }
 138
 139
 140 static int qio_channel_buffer_close(QIOChannel *ioc,
 141                                     Error **errp)
 142 {
 143     QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
 144
 145     g_free(bioc->data);
 146     bioc->data = NULL;
 147     bioc->capacity = bioc->usage = bioc->offset = 0;
 148
 149     return 0;
 150 }
 151
 152
 153 typedef struct QIOChannelBufferSource QIOChannelBufferSource;
 154 struct QIOChannelBufferSource {
 155     GSource parent;
 156     QIOChannelBuffer *bioc;
 157     GIOCondition condition;
 158 };
 159
 160 static gboolean
 161 qio_channel_buffer_source_prepare(GSource *source,
 162                                   gint *timeout)
 163 {
 164     QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
 165
 166     *timeout = -1;
 167
 168     return (G_IO_IN | G_IO_OUT) & bsource->condition;
 169 }
 170
 171 static gboolean
 172 qio_channel_buffer_source_check(GSource *source)
 173 {
 174     QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
 175
 176     return (G_IO_IN | G_IO_OUT) & bsource->condition;
 177 }
 178
 179 static gboolean
 180 qio_channel_buffer_source_dispatch(GSource *source,
 181                                    GSourceFunc callback,
 182                                    gpointer user_data)
 183 {
 184     QIOChannelFunc func = (QIOChannelFunc)callback;
 185     QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
 186
 187     return (*func)(QIO_CHANNEL(bsource->bioc),
 188                    ((G_IO_IN | G_IO_OUT) & bsource->condition),
 189                    user_data);
 190 }
 191
 192 static void
 193 qio_channel_buffer_source_finalize(GSource *source)
 194 {
 195     QIOChannelBufferSource *ssource = (QIOChannelBufferSource *)source;
 196
 197     object_unref(OBJECT(ssource->bioc));
 198 }
 199
 200 GSourceFuncs qio_channel_buffer_source_funcs = {
 201     qio_channel_buffer_source_prepare,
 202     qio_channel_buffer_source_check,
 203     qio_channel_buffer_source_dispatch,
 204     qio_channel_buffer_source_finalize
 205 };
 206
 207 static GSource *qio_channel_buffer_create_watch(QIOChannel *ioc,
 208                                                 GIOCondition condition)
 209 {
 210     QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
 211     QIOChannelBufferSource *ssource;
 212     GSource *source;
 213
 214     source = g_source_new(&qio_channel_buffer_source_funcs,
 215                           sizeof(QIOChannelBufferSource));
 216     ssource = (QIOChannelBufferSource *)source;
 217
 218     ssource->bioc = bioc;
 219     object_ref(OBJECT(bioc));
 220
 221     ssource->condition = condition;
 222
 223     return source;
 224 }
 225
 226
 227 static void qio_channel_buffer_class_init(ObjectClass *klass,
 228                                           void *class_data G_GNUC_UNUSED)
 229 {
 230     QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
 231
 232     ioc_klass->io_writev = qio_channel_buffer_writev;
 233     ioc_klass->io_readv = qio_channel_buffer_readv;
 234     ioc_klass->io_set_blocking = qio_channel_buffer_set_blocking;
 235     ioc_klass->io_seek = qio_channel_buffer_seek;
 236     ioc_klass->io_close = qio_channel_buffer_close;
 237     ioc_klass->io_create_watch = qio_channel_buffer_create_watch;
 238 }
 239
 240 static const TypeInfo qio_channel_buffer_info = {
 241     .parent = TYPE_QIO_CHANNEL,
 242     .name = TYPE_QIO_CHANNEL_BUFFER,
 243     .instance_size = sizeof(QIOChannelBuffer),
 244     .instance_finalize = qio_channel_buffer_finalize,
 245     .class_init = qio_channel_buffer_class_init,
 246 };
 247
 248 static void qio_channel_buffer_register_types(void)
 249 {
 250     type_register_static(&qio_channel_buffer_info);
 251 }
 252
 253 type_init(qio_channel_buffer_register_types);