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 void qio_channel_set_name(QIOChannel *ioc,
  41                           const char *name)
  42 {
  43     g_free(ioc->name);
  44     ioc->name = g_strdup(name);
  45 }
  46
  47
  48 ssize_t qio_channel_readv_full(QIOChannel *ioc,
  49                                const struct iovec *iov,
  50                                size_t niov,
  51                                int **fds,
  52                                size_t *nfds,
  53                                Error **errp)
  54 {
  55     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
  56
  57     if ((fds || nfds) &&
  58         !qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) {
  59         error_setg_errno(errp, EINVAL,
  60                          "Channel does not support file descriptor passing");
  61         return -1;
  62     }
  63
  64     return klass->io_readv(ioc, iov, niov, fds, nfds, errp);
  65 }
  66
  67
  68 ssize_t qio_channel_writev_full(QIOChannel *ioc,
  69                                 const struct iovec *iov,
  70                                 size_t niov,
  71                                 int *fds,
  72                                 size_t nfds,
  73                                 Error **errp)
  74 {
  75     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
  76
  77     if ((fds || nfds) &&
  78         !qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) {
  79         error_setg_errno(errp, EINVAL,
  80                          "Channel does not support file descriptor passing");
  81         return -1;
  82     }
  83
  84     return klass->io_writev(ioc, iov, niov, fds, nfds, errp);
  85 }
  86
  87
  88 ssize_t qio_channel_readv(QIOChannel *ioc,
  89                           const struct iovec *iov,
  90                           size_t niov,
  91                           Error **errp)
  92 {
  93     return qio_channel_readv_full(ioc, iov, niov, NULL, NULL, errp);
  94 }
  95
  96
  97 ssize_t qio_channel_writev(QIOChannel *ioc,
  98                            const struct iovec *iov,
  99                            size_t niov,
 100                            Error **errp)
 101 {
 102     return qio_channel_writev_full(ioc, iov, niov, NULL, 0, errp);
 103 }
 104
 105
 106 ssize_t qio_channel_read(QIOChannel *ioc,
 107                          char *buf,
 108                          size_t buflen,
 109                          Error **errp)
 110 {
 111     struct iovec iov = { .iov_base = buf, .iov_len = buflen };
 112     return qio_channel_readv_full(ioc, &iov, 1, NULL, NULL, errp);
 113 }
 114
 115
 116 ssize_t qio_channel_write(QIOChannel *ioc,
 117                           const char *buf,
 118                           size_t buflen,
 119                           Error **errp)
 120 {
 121     struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };
 122     return qio_channel_writev_full(ioc, &iov, 1, NULL, 0, errp);
 123 }
 124
 125
 126 int qio_channel_set_blocking(QIOChannel *ioc,
 127                               bool enabled,
 128                               Error **errp)
 129 {
 130     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 131     return klass->io_set_blocking(ioc, enabled, errp);
 132 }
 133
 134
 135 int qio_channel_close(QIOChannel *ioc,
 136                       Error **errp)
 137 {
 138     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 139     return klass->io_close(ioc, errp);
 140 }
 141
 142
 143 GSource *qio_channel_create_watch(QIOChannel *ioc,
 144                                   GIOCondition condition)
 145 {
 146     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 147     GSource *ret = klass->io_create_watch(ioc, condition);
 148
 149     if (ioc->name) {
 150         g_source_set_name(ret, ioc->name);
 151     }
 152
 153     return ret;
 154 }
 155
 156
 157 guint qio_channel_add_watch(QIOChannel *ioc,
 158                             GIOCondition condition,
 159                             QIOChannelFunc func,
 160                             gpointer user_data,
 161                             GDestroyNotify notify)
 162 {
 163     GSource *source;
 164     guint id;
 165
 166     source = qio_channel_create_watch(ioc, condition);
 167
 168     g_source_set_callback(source, (GSourceFunc)func, user_data, notify);
 169
 170     id = g_source_attach(source, NULL);
 171     g_source_unref(source);
 172
 173     return id;
 174 }
 175
 176
 177 int qio_channel_shutdown(QIOChannel *ioc,
 178                          QIOChannelShutdown how,
 179                          Error **errp)
 180 {
 181     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 182
 183     if (!klass->io_shutdown) {
 184         error_setg(errp, "Data path shutdown not supported");
 185         return -1;
 186     }
 187
 188     return klass->io_shutdown(ioc, how, errp);
 189 }
 190
 191
 192 void qio_channel_set_delay(QIOChannel *ioc,
 193                            bool enabled)
 194 {
 195     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 196
 197     if (klass->io_set_delay) {
 198         klass->io_set_delay(ioc, enabled);
 199     }
 200 }
 201
 202
 203 void qio_channel_set_cork(QIOChannel *ioc,
 204                           bool enabled)
 205 {
 206     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 207
 208     if (klass->io_set_cork) {
 209         klass->io_set_cork(ioc, enabled);
 210     }
 211 }
 212
 213
 214 off_t qio_channel_io_seek(QIOChannel *ioc,
 215                           off_t offset,
 216                           int whence,
 217                           Error **errp)
 218 {
 219     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 220
 221     if (!klass->io_seek) {
 222         error_setg(errp, "Channel does not support random access");
 223         return -1;
 224     }
 225
 226     return klass->io_seek(ioc, offset, whence, errp);
 227 }
 228
 229
 230 typedef struct QIOChannelYieldData QIOChannelYieldData;
 231 struct QIOChannelYieldData {
 232     QIOChannel *ioc;
 233     Coroutine *co;
 234 };
 235
 236
 237 static gboolean qio_channel_yield_enter(QIOChannel *ioc,
 238                                         GIOCondition condition,
 239                                         gpointer opaque)
 240 {
 241     QIOChannelYieldData *data = opaque;
 242     qemu_coroutine_enter(data->co);
 243     return FALSE;
 244 }
 245
 246
 247 void coroutine_fn qio_channel_yield(QIOChannel *ioc,
 248                                     GIOCondition condition)
 249 {
 250     QIOChannelYieldData data;
 251
 252     assert(qemu_in_coroutine());
 253     data.ioc = ioc;
 254     data.co = qemu_coroutine_self();
 255     qio_channel_add_watch(ioc,
 256                           condition,
 257                           qio_channel_yield_enter,
 258                           &data,
 259                           NULL);
 260     qemu_coroutine_yield();
 261 }
 262
 263
 264 static gboolean qio_channel_wait_complete(QIOChannel *ioc,
 265                                           GIOCondition condition,
 266                                           gpointer opaque)
 267 {
 268     GMainLoop *loop = opaque;
 269
 270     g_main_loop_quit(loop);
 271     return FALSE;
 272 }
 273
 274
 275 void qio_channel_wait(QIOChannel *ioc,
 276                       GIOCondition condition)
 277 {
 278     GMainContext *ctxt = g_main_context_new();
 279     GMainLoop *loop = g_main_loop_new(ctxt, TRUE);
 280     GSource *source;
 281
 282     source = qio_channel_create_watch(ioc, condition);
 283
 284     g_source_set_callback(source,
 285                           (GSourceFunc)qio_channel_wait_complete,
 286                           loop,
 287                           NULL);
 288
 289     g_source_attach(source, ctxt);
 290
 291     g_main_loop_run(loop);
 292
 293     g_source_unref(source);
 294     g_main_loop_unref(loop);
 295     g_main_context_unref(ctxt);
 296 }
 297
 298
 299 static void qio_channel_finalize(Object *obj)
 300 {
 301     QIOChannel *ioc = QIO_CHANNEL(obj);
 302
 303     g_free(ioc->name);
 304
 305 #ifdef _WIN32
 306     if (ioc->event) {
 307         CloseHandle(ioc->event);
 308     }
 309 #endif
 310 }
 311
 312 static const TypeInfo qio_channel_info = {
 313     .parent = TYPE_OBJECT,
 314     .name = TYPE_QIO_CHANNEL,
 315     .instance_size = sizeof(QIOChannel),
 316     .instance_finalize = qio_channel_finalize,
 317     .abstract = true,
 318     .class_size = sizeof(QIOChannelClass),
 319 };
 320
 321
 322 static void qio_channel_register_types(void)
 323 {
 324     type_register_static(&qio_channel_info);
 325 }
 326
 327
 328 type_init(qio_channel_register_types);