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