io/channel.c

   1 /*
   2  * QEMU I/O channels
   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.h"
  23 #include "qemu/coroutine.h"
  24
  25 bool qio_channel_has_feature(QIOChannel *ioc,
  26                              QIOChannelFeature feature)
  27 {
  28     return ioc->features & (1 << feature);
  29 }
  30
  31
  32 ssize_t qio_channel_readv_full(QIOChannel *ioc,
  33                                const struct iovec *iov,
  34                                size_t niov,
  35                                int **fds,
  36                                size_t *nfds,
  37                                Error **errp)
  38 {
  39     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
  40
  41     if ((fds || nfds) &&
  42         !(ioc->features & (1 << QIO_CHANNEL_FEATURE_FD_PASS))) {
  43         error_setg_errno(errp, EINVAL,
  44                          "Channel does not support file descriptor passing");
  45         return -1;
  46     }
  47
  48     return klass->io_readv(ioc, iov, niov, fds, nfds, errp);
  49 }
  50
  51
  52 ssize_t qio_channel_writev_full(QIOChannel *ioc,
  53                                 const struct iovec *iov,
  54                                 size_t niov,
  55                                 int *fds,
  56                                 size_t nfds,
  57                                 Error **errp)
  58 {
  59     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
  60
  61     if ((fds || nfds) &&
  62         !(ioc->features & (1 << QIO_CHANNEL_FEATURE_FD_PASS))) {
  63         error_setg_errno(errp, EINVAL,
  64                          "Channel does not support file descriptor passing");
  65         return -1;
  66     }
  67
  68     return klass->io_writev(ioc, iov, niov, fds, nfds, errp);
  69 }
  70
  71
  72 ssize_t qio_channel_readv(QIOChannel *ioc,
  73                           const struct iovec *iov,
  74                           size_t niov,
  75                           Error **errp)
  76 {
  77     return qio_channel_readv_full(ioc, iov, niov, NULL, NULL, errp);
  78 }
  79
  80
  81 ssize_t qio_channel_writev(QIOChannel *ioc,
  82                            const struct iovec *iov,
  83                            size_t niov,
  84                            Error **errp)
  85 {
  86     return qio_channel_writev_full(ioc, iov, niov, NULL, 0, errp);
  87 }
  88
  89
  90 ssize_t qio_channel_read(QIOChannel *ioc,
  91                          char *buf,
  92                          size_t buflen,
  93                          Error **errp)
  94 {
  95     struct iovec iov = { .iov_base = buf, .iov_len = buflen };
  96     return qio_channel_readv_full(ioc, &iov, 1, NULL, NULL, errp);
  97 }
  98
  99
 100 ssize_t qio_channel_write(QIOChannel *ioc,
 101                           const char *buf,
 102                           size_t buflen,
 103                           Error **errp)
 104 {
 105     struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };
 106     return qio_channel_writev_full(ioc, &iov, 1, NULL, 0, errp);
 107 }
 108
 109
 110 int qio_channel_set_blocking(QIOChannel *ioc,
 111                               bool enabled,
 112                               Error **errp)
 113 {
 114     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 115     return klass->io_set_blocking(ioc, enabled, errp);
 116 }
 117
 118
 119 int qio_channel_close(QIOChannel *ioc,
 120                       Error **errp)
 121 {
 122     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 123     return klass->io_close(ioc, errp);
 124 }
 125
 126
 127 GSource *qio_channel_create_watch(QIOChannel *ioc,
 128                                   GIOCondition condition)
 129 {
 130     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 131     return klass->io_create_watch(ioc, condition);
 132 }
 133
 134
 135 guint qio_channel_add_watch(QIOChannel *ioc,
 136                             GIOCondition condition,
 137                             QIOChannelFunc func,
 138                             gpointer user_data,
 139                             GDestroyNotify notify)
 140 {
 141     GSource *source;
 142     guint id;
 143
 144     source = qio_channel_create_watch(ioc, condition);
 145
 146     g_source_set_callback(source, (GSourceFunc)func, user_data, notify);
 147
 148     id = g_source_attach(source, NULL);
 149     g_source_unref(source);
 150
 151     return id;
 152 }
 153
 154
 155 int qio_channel_shutdown(QIOChannel *ioc,
 156                          QIOChannelShutdown how,
 157                          Error **errp)
 158 {
 159     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 160
 161     if (!klass->io_shutdown) {
 162         error_setg(errp, "Data path shutdown not supported");
 163         return -1;
 164     }
 165
 166     return klass->io_shutdown(ioc, how, errp);
 167 }
 168
 169
 170 void qio_channel_set_delay(QIOChannel *ioc,
 171                            bool enabled)
 172 {
 173     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 174
 175     if (klass->io_set_delay) {
 176         klass->io_set_delay(ioc, enabled);
 177     }
 178 }
 179
 180
 181 void qio_channel_set_cork(QIOChannel *ioc,
 182                           bool enabled)
 183 {
 184     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 185
 186     if (klass->io_set_cork) {
 187         klass->io_set_cork(ioc, enabled);
 188     }
 189 }
 190
 191
 192 off_t qio_channel_io_seek(QIOChannel *ioc,
 193                           off_t offset,
 194                           int whence,
 195                           Error **errp)
 196 {
 197     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 198
 199     if (!klass->io_seek) {
 200         error_setg(errp, "Channel does not support random access");
 201         return -1;
 202     }
 203
 204     return klass->io_seek(ioc, offset, whence, errp);
 205 }
 206
 207
 208 typedef struct QIOChannelYieldData QIOChannelYieldData;
 209 struct QIOChannelYieldData {
 210     QIOChannel *ioc;
 211     Coroutine *co;
 212 };
 213
 214
 215 static gboolean qio_channel_yield_enter(QIOChannel *ioc,
 216                                         GIOCondition condition,
 217                                         gpointer opaque)
 218 {
 219     QIOChannelYieldData *data = opaque;
 220     qemu_coroutine_enter(data->co, NULL);
 221     return FALSE;
 222 }
 223
 224
 225 void coroutine_fn qio_channel_yield(QIOChannel *ioc,
 226                                     GIOCondition condition)
 227 {
 228     QIOChannelYieldData data;
 229
 230     assert(qemu_in_coroutine());
 231     data.ioc = ioc;
 232     data.co = qemu_coroutine_self();
 233     qio_channel_add_watch(ioc,
 234                           condition,
 235                           qio_channel_yield_enter,
 236                           &data,
 237                           NULL);
 238     qemu_coroutine_yield();
 239 }
 240
 241
 242 static gboolean qio_channel_wait_complete(QIOChannel *ioc,
 243                                           GIOCondition condition,
 244                                           gpointer opaque)
 245 {
 246     GMainLoop *loop = opaque;
 247
 248     g_main_loop_quit(loop);
 249     return FALSE;
 250 }
 251
 252
 253 void qio_channel_wait(QIOChannel *ioc,
 254                       GIOCondition condition)
 255 {
 256     GMainContext *ctxt = g_main_context_new();
 257     GMainLoop *loop = g_main_loop_new(ctxt, TRUE);
 258     GSource *source;
 259
 260     source = qio_channel_create_watch(ioc, condition);
 261
 262     g_source_set_callback(source,
 263                           (GSourceFunc)qio_channel_wait_complete,
 264                           loop,
 265                           NULL);
 266
 267     g_source_attach(source, ctxt);
 268
 269     g_main_loop_run(loop);
 270
 271     g_source_unref(source);
 272     g_main_loop_unref(loop);
 273     g_main_context_unref(ctxt);
 274 }
 275
 276
 277 static const TypeInfo qio_channel_info = {
 278     .parent = TYPE_OBJECT,
 279     .name = TYPE_QIO_CHANNEL,
 280     .instance_size = sizeof(QIOChannel),
 281     .abstract = true,
 282     .class_size = sizeof(QIOChannelClass),
 283 };
 284
 285
 286 static void qio_channel_register_types(void)
 287 {
 288     type_register_static(&qio_channel_info);
 289 }
 290
 291
 292 type_init(qio_channel_register_types);