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 "qapi/error.h"
  24 #include "qemu/coroutine.h"
  25
  26 bool qio_channel_has_feature(QIOChannel *ioc,
  27                              QIOChannelFeature feature)
  28 {
  29     return ioc->features & (1 << feature);
  30 }
  31
  32
  33 void qio_channel_set_feature(QIOChannel *ioc,
  34                              QIOChannelFeature feature)
  35 {
  36     ioc->features |= (1 << feature);
  37 }
  38
  39
  40 ssize_t qio_channel_readv_full(QIOChannel *ioc,
  41                                const struct iovec *iov,
  42                                size_t niov,
  43                                int **fds,
  44                                size_t *nfds,
  45                                Error **errp)
  46 {
  47     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
  48
  49     if ((fds || nfds) &&
  50         !qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) {
  51         error_setg_errno(errp, EINVAL,
  52                          "Channel does not support file descriptor passing");
  53         return -1;
  54     }
  55
  56     return klass->io_readv(ioc, iov, niov, fds, nfds, errp);
  57 }
  58
  59
  60 ssize_t qio_channel_writev_full(QIOChannel *ioc,
  61                                 const struct iovec *iov,
  62                                 size_t niov,
  63                                 int *fds,
  64                                 size_t nfds,
  65                                 Error **errp)
  66 {
  67     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
  68
  69     if ((fds || nfds) &&
  70         !qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) {
  71         error_setg_errno(errp, EINVAL,
  72                          "Channel does not support file descriptor passing");
  73         return -1;
  74     }
  75
  76     return klass->io_writev(ioc, iov, niov, fds, nfds, errp);
  77 }
  78
  79
  80 ssize_t qio_channel_readv(QIOChannel *ioc,
  81                           const struct iovec *iov,
  82                           size_t niov,
  83                           Error **errp)
  84 {
  85     return qio_channel_readv_full(ioc, iov, niov, NULL, NULL, errp);
  86 }
  87
  88
  89 ssize_t qio_channel_writev(QIOChannel *ioc,
  90                            const struct iovec *iov,
  91                            size_t niov,
  92                            Error **errp)
  93 {
  94     return qio_channel_writev_full(ioc, iov, niov, NULL, 0, errp);
  95 }
  96
  97
  98 ssize_t qio_channel_read(QIOChannel *ioc,
  99                          char *buf,
 100                          size_t buflen,
 101                          Error **errp)
 102 {
 103     struct iovec iov = { .iov_base = buf, .iov_len = buflen };
 104     return qio_channel_readv_full(ioc, &iov, 1, NULL, NULL, errp);
 105 }
 106
 107
 108 ssize_t qio_channel_write(QIOChannel *ioc,
 109                           const char *buf,
 110                           size_t buflen,
 111                           Error **errp)
 112 {
 113     struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };
 114     return qio_channel_writev_full(ioc, &iov, 1, NULL, 0, errp);
 115 }
 116
 117
 118 int qio_channel_set_blocking(QIOChannel *ioc,
 119                               bool enabled,
 120                               Error **errp)
 121 {
 122     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 123     return klass->io_set_blocking(ioc, enabled, errp);
 124 }
 125
 126
 127 int qio_channel_close(QIOChannel *ioc,
 128                       Error **errp)
 129 {
 130     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 131     return klass->io_close(ioc, errp);
 132 }
 133
 134
 135 GSource *qio_channel_create_watch(QIOChannel *ioc,
 136                                   GIOCondition condition)
 137 {
 138     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 139     return klass->io_create_watch(ioc, condition);
 140 }
 141
 142
 143 guint qio_channel_add_watch(QIOChannel *ioc,
 144                             GIOCondition condition,
 145                             QIOChannelFunc func,
 146                             gpointer user_data,
 147                             GDestroyNotify notify)
 148 {
 149     GSource *source;
 150     guint id;
 151
 152     source = qio_channel_create_watch(ioc, condition);
 153
 154     g_source_set_callback(source, (GSourceFunc)func, user_data, notify);
 155
 156     id = g_source_attach(source, NULL);
 157     g_source_unref(source);
 158
 159     return id;
 160 }
 161
 162
 163 int qio_channel_shutdown(QIOChannel *ioc,
 164                          QIOChannelShutdown how,
 165                          Error **errp)
 166 {
 167     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 168
 169     if (!klass->io_shutdown) {
 170         error_setg(errp, "Data path shutdown not supported");
 171         return -1;
 172     }
 173
 174     return klass->io_shutdown(ioc, how, errp);
 175 }
 176
 177
 178 void qio_channel_set_delay(QIOChannel *ioc,
 179                            bool enabled)
 180 {
 181     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 182
 183     if (klass->io_set_delay) {
 184         klass->io_set_delay(ioc, enabled);
 185     }
 186 }
 187
 188
 189 void qio_channel_set_cork(QIOChannel *ioc,
 190                           bool enabled)
 191 {
 192     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 193
 194     if (klass->io_set_cork) {
 195         klass->io_set_cork(ioc, enabled);
 196     }
 197 }
 198
 199
 200 off_t qio_channel_io_seek(QIOChannel *ioc,
 201                           off_t offset,
 202                           int whence,
 203                           Error **errp)
 204 {
 205     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 206
 207     if (!klass->io_seek) {
 208         error_setg(errp, "Channel does not support random access");
 209         return -1;
 210     }
 211
 212     return klass->io_seek(ioc, offset, whence, errp);
 213 }
 214
 215
 216 typedef struct QIOChannelYieldData QIOChannelYieldData;
 217 struct QIOChannelYieldData {
 218     QIOChannel *ioc;
 219     Coroutine *co;
 220 };
 221
 222
 223 static gboolean qio_channel_yield_enter(QIOChannel *ioc,
 224                                         GIOCondition condition,
 225                                         gpointer opaque)
 226 {
 227     QIOChannelYieldData *data = opaque;
 228     qemu_coroutine_enter(data->co);
 229     return FALSE;
 230 }
 231
 232
 233 void coroutine_fn qio_channel_yield(QIOChannel *ioc,
 234                                     GIOCondition condition)
 235 {
 236     QIOChannelYieldData data;
 237
 238     assert(qemu_in_coroutine());
 239     data.ioc = ioc;
 240     data.co = qemu_coroutine_self();
 241     qio_channel_add_watch(ioc,
 242                           condition,
 243                           qio_channel_yield_enter,
 244                           &data,
 245                           NULL);
 246     qemu_coroutine_yield();
 247 }
 248
 249
 250 static gboolean qio_channel_wait_complete(QIOChannel *ioc,
 251                                           GIOCondition condition,
 252                                           gpointer opaque)
 253 {
 254     GMainLoop *loop = opaque;
 255
 256     g_main_loop_quit(loop);
 257     return FALSE;
 258 }
 259
 260
 261 void qio_channel_wait(QIOChannel *ioc,
 262                       GIOCondition condition)
 263 {
 264     GMainContext *ctxt = g_main_context_new();
 265     GMainLoop *loop = g_main_loop_new(ctxt, TRUE);
 266     GSource *source;
 267
 268     source = qio_channel_create_watch(ioc, condition);
 269
 270     g_source_set_callback(source,
 271                           (GSourceFunc)qio_channel_wait_complete,
 272                           loop,
 273                           NULL);
 274
 275     g_source_attach(source, ctxt);
 276
 277     g_main_loop_run(loop);
 278
 279     g_source_unref(source);
 280     g_main_loop_unref(loop);
 281     g_main_context_unref(ctxt);
 282 }
 283
 284
 285 #ifdef _WIN32
 286 static void qio_channel_finalize(Object *obj)
 287 {
 288     QIOChannel *ioc = QIO_CHANNEL(obj);
 289
 290     if (ioc->event) {
 291         CloseHandle(ioc->event);
 292     }
 293 }
 294 #endif
 295
 296 static const TypeInfo qio_channel_info = {
 297     .parent = TYPE_OBJECT,
 298     .name = TYPE_QIO_CHANNEL,
 299     .instance_size = sizeof(QIOChannel),
 300 #ifdef _WIN32
 301     .instance_finalize = qio_channel_finalize,
 302 #endif
 303     .abstract = true,
 304     .class_size = sizeof(QIOChannelClass),
 305 };
 306
 307
 308 static void qio_channel_register_types(void)
 309 {
 310     type_register_static(&qio_channel_info);
 311 }
 312
 313
 314 type_init(qio_channel_register_types);