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