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/main-loop.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 void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
 158                                     AioContext *ctx,
 159                                     IOHandler *io_read,
 160                                     IOHandler *io_write,
 161                                     void *opaque)
 162 {
 163     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 164
 165     klass->io_set_aio_fd_handler(ioc, ctx, io_read, io_write, opaque);
 166 }
 167
 168 guint qio_channel_add_watch(QIOChannel *ioc,
 169                             GIOCondition condition,
 170                             QIOChannelFunc func,
 171                             gpointer user_data,
 172                             GDestroyNotify notify)
 173 {
 174     GSource *source;
 175     guint id;
 176
 177     source = qio_channel_create_watch(ioc, condition);
 178
 179     g_source_set_callback(source, (GSourceFunc)func, user_data, notify);
 180
 181     id = g_source_attach(source, NULL);
 182     g_source_unref(source);
 183
 184     return id;
 185 }
 186
 187
 188 int qio_channel_shutdown(QIOChannel *ioc,
 189                          QIOChannelShutdown how,
 190                          Error **errp)
 191 {
 192     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 193
 194     if (!klass->io_shutdown) {
 195         error_setg(errp, "Data path shutdown not supported");
 196         return -1;
 197     }
 198
 199     return klass->io_shutdown(ioc, how, errp);
 200 }
 201
 202
 203 void qio_channel_set_delay(QIOChannel *ioc,
 204                            bool enabled)
 205 {
 206     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 207
 208     if (klass->io_set_delay) {
 209         klass->io_set_delay(ioc, enabled);
 210     }
 211 }
 212
 213
 214 void qio_channel_set_cork(QIOChannel *ioc,
 215                           bool enabled)
 216 {
 217     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 218
 219     if (klass->io_set_cork) {
 220         klass->io_set_cork(ioc, enabled);
 221     }
 222 }
 223
 224
 225 off_t qio_channel_io_seek(QIOChannel *ioc,
 226                           off_t offset,
 227                           int whence,
 228                           Error **errp)
 229 {
 230     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 231
 232     if (!klass->io_seek) {
 233         error_setg(errp, "Channel does not support random access");
 234         return -1;
 235     }
 236
 237     return klass->io_seek(ioc, offset, whence, errp);
 238 }
 239
 240
 241 static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc);
 242
 243 static void qio_channel_restart_read(void *opaque)
 244 {
 245     QIOChannel *ioc = opaque;
 246     Coroutine *co = ioc->read_coroutine;
 247
 248     ioc->read_coroutine = NULL;
 249     qio_channel_set_aio_fd_handlers(ioc);
 250     aio_co_wake(co);
 251 }
 252
 253 static void qio_channel_restart_write(void *opaque)
 254 {
 255     QIOChannel *ioc = opaque;
 256     Coroutine *co = ioc->write_coroutine;
 257
 258     ioc->write_coroutine = NULL;
 259     qio_channel_set_aio_fd_handlers(ioc);
 260     aio_co_wake(co);
 261 }
 262
 263 static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc)
 264 {
 265     IOHandler *rd_handler = NULL, *wr_handler = NULL;
 266     AioContext *ctx;
 267
 268     if (ioc->read_coroutine) {
 269         rd_handler = qio_channel_restart_read;
 270     }
 271     if (ioc->write_coroutine) {
 272         wr_handler = qio_channel_restart_write;
 273     }
 274
 275     ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context();
 276     qio_channel_set_aio_fd_handler(ioc, ctx, rd_handler, wr_handler, ioc);
 277 }
 278
 279 void qio_channel_attach_aio_context(QIOChannel *ioc,
 280                                     AioContext *ctx)
 281 {
 282     AioContext *old_ctx;
 283     if (ioc->ctx == ctx) {
 284         return;
 285     }
 286
 287     old_ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context();
 288     qio_channel_set_aio_fd_handler(ioc, old_ctx, NULL, NULL, NULL);
 289     ioc->ctx = ctx;
 290     qio_channel_set_aio_fd_handlers(ioc);
 291 }
 292
 293 void qio_channel_detach_aio_context(QIOChannel *ioc)
 294 {
 295     ioc->read_coroutine = NULL;
 296     ioc->write_coroutine = NULL;
 297     qio_channel_set_aio_fd_handlers(ioc);
 298     ioc->ctx = NULL;
 299 }
 300
 301 void coroutine_fn qio_channel_yield(QIOChannel *ioc,
 302                                     GIOCondition condition)
 303 {
 304     assert(qemu_in_coroutine());
 305     if (condition == G_IO_IN) {
 306         assert(!ioc->read_coroutine);
 307         ioc->read_coroutine = qemu_coroutine_self();
 308     } else if (condition == G_IO_OUT) {
 309         assert(!ioc->write_coroutine);
 310         ioc->write_coroutine = qemu_coroutine_self();
 311     } else {
 312         abort();
 313     }
 314     qio_channel_set_aio_fd_handlers(ioc);
 315     qemu_coroutine_yield();
 316 }
 317
 318
 319 static gboolean qio_channel_wait_complete(QIOChannel *ioc,
 320                                           GIOCondition condition,
 321                                           gpointer opaque)
 322 {
 323     GMainLoop *loop = opaque;
 324
 325     g_main_loop_quit(loop);
 326     return FALSE;
 327 }
 328
 329
 330 void qio_channel_wait(QIOChannel *ioc,
 331                       GIOCondition condition)
 332 {
 333     GMainContext *ctxt = g_main_context_new();
 334     GMainLoop *loop = g_main_loop_new(ctxt, TRUE);
 335     GSource *source;
 336
 337     source = qio_channel_create_watch(ioc, condition);
 338
 339     g_source_set_callback(source,
 340                           (GSourceFunc)qio_channel_wait_complete,
 341                           loop,
 342                           NULL);
 343
 344     g_source_attach(source, ctxt);
 345
 346     g_main_loop_run(loop);
 347
 348     g_source_unref(source);
 349     g_main_loop_unref(loop);
 350     g_main_context_unref(ctxt);
 351 }
 352
 353
 354 static void qio_channel_finalize(Object *obj)
 355 {
 356     QIOChannel *ioc = QIO_CHANNEL(obj);
 357
 358     g_free(ioc->name);
 359
 360 #ifdef _WIN32
 361     if (ioc->event) {
 362         CloseHandle(ioc->event);
 363     }
 364 #endif
 365 }
 366
 367 static const TypeInfo qio_channel_info = {
 368     .parent = TYPE_OBJECT,
 369     .name = TYPE_QIO_CHANNEL,
 370     .instance_size = sizeof(QIOChannel),
 371     .instance_finalize = qio_channel_finalize,
 372     .abstract = true,
 373     .class_size = sizeof(QIOChannelClass),
 374 };
 375
 376
 377 static void qio_channel_register_types(void)
 378 {
 379     type_register_static(&qio_channel_info);
 380 }
 381
 382
 383 type_init(qio_channel_register_types);