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