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 #include "qemu/iov.h"
  26
  27 bool qio_channel_has_feature(QIOChannel *ioc,
  28                              QIOChannelFeature feature)
  29 {
  30     return ioc->features & (1 << feature);
  31 }
  32
  33
  34 void qio_channel_set_feature(QIOChannel *ioc,
  35                              QIOChannelFeature feature)
  36 {
  37     ioc->features |= (1 << feature);
  38 }
  39
  40
  41 void qio_channel_set_name(QIOChannel *ioc,
  42                           const char *name)
  43 {
  44     g_free(ioc->name);
  45     ioc->name = g_strdup(name);
  46 }
  47
  48
  49 ssize_t qio_channel_readv_full(QIOChannel *ioc,
  50                                const struct iovec *iov,
  51                                size_t niov,
  52                                int **fds,
  53                                size_t *nfds,
  54                                Error **errp)
  55 {
  56     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
  57
  58     if ((fds || nfds) &&
  59         !qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) {
  60         error_setg_errno(errp, EINVAL,
  61                          "Channel does not support file descriptor passing");
  62         return -1;
  63     }
  64
  65     return klass->io_readv(ioc, iov, niov, fds, nfds, errp);
  66 }
  67
  68
  69 ssize_t qio_channel_writev_full(QIOChannel *ioc,
  70                                 const struct iovec *iov,
  71                                 size_t niov,
  72                                 int *fds,
  73                                 size_t nfds,
  74                                 Error **errp)
  75 {
  76     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
  77
  78     if ((fds || nfds) &&
  79         !qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) {
  80         error_setg_errno(errp, EINVAL,
  81                          "Channel does not support file descriptor passing");
  82         return -1;
  83     }
  84
  85     return klass->io_writev(ioc, iov, niov, fds, nfds, errp);
  86 }
  87
  88
  89
  90 int qio_channel_readv_all(QIOChannel *ioc,
  91                           const struct iovec *iov,
  92                           size_t niov,
  93                           Error **errp)
  94 {
  95     int ret = -1;
  96     struct iovec *local_iov = g_new(struct iovec, niov);
  97     struct iovec *local_iov_head = local_iov;
  98     unsigned int nlocal_iov = niov;
  99
 100     nlocal_iov = iov_copy(local_iov, nlocal_iov,
 101                           iov, niov,
 102                           0, iov_size(iov, niov));
 103
 104     while (nlocal_iov > 0) {
 105         ssize_t len;
 106         len = qio_channel_readv(ioc, local_iov, nlocal_iov, errp);
 107         if (len == QIO_CHANNEL_ERR_BLOCK) {
 108             qio_channel_wait(ioc, G_IO_IN);
 109             continue;
 110         } else if (len < 0) {
 111             goto cleanup;
 112         } else if (len == 0) {
 113             error_setg(errp,
 114                        "Unexpected end-of-file before all bytes were read");
 115             goto cleanup;
 116         }
 117
 118         iov_discard_front(&local_iov, &nlocal_iov, len);
 119     }
 120
 121     ret = 0;
 122
 123  cleanup:
 124     g_free(local_iov_head);
 125     return ret;
 126 }
 127
 128 int qio_channel_writev_all(QIOChannel *ioc,
 129                            const struct iovec *iov,
 130                            size_t niov,
 131                            Error **errp)
 132 {
 133     int ret = -1;
 134     struct iovec *local_iov = g_new(struct iovec, niov);
 135     struct iovec *local_iov_head = local_iov;
 136     unsigned int nlocal_iov = niov;
 137
 138     nlocal_iov = iov_copy(local_iov, nlocal_iov,
 139                           iov, niov,
 140                           0, iov_size(iov, niov));
 141
 142     while (nlocal_iov > 0) {
 143         ssize_t len;
 144         len = qio_channel_writev(ioc, local_iov, nlocal_iov, errp);
 145         if (len == QIO_CHANNEL_ERR_BLOCK) {
 146             qio_channel_wait(ioc, G_IO_OUT);
 147             continue;
 148         }
 149         if (len < 0) {
 150             goto cleanup;
 151         }
 152
 153         iov_discard_front(&local_iov, &nlocal_iov, len);
 154     }
 155
 156     ret = 0;
 157  cleanup:
 158     g_free(local_iov_head);
 159     return ret;
 160 }
 161
 162 ssize_t qio_channel_readv(QIOChannel *ioc,
 163                           const struct iovec *iov,
 164                           size_t niov,
 165                           Error **errp)
 166 {
 167     return qio_channel_readv_full(ioc, iov, niov, NULL, NULL, errp);
 168 }
 169
 170
 171 ssize_t qio_channel_writev(QIOChannel *ioc,
 172                            const struct iovec *iov,
 173                            size_t niov,
 174                            Error **errp)
 175 {
 176     return qio_channel_writev_full(ioc, iov, niov, NULL, 0, errp);
 177 }
 178
 179
 180 ssize_t qio_channel_read(QIOChannel *ioc,
 181                          char *buf,
 182                          size_t buflen,
 183                          Error **errp)
 184 {
 185     struct iovec iov = { .iov_base = buf, .iov_len = buflen };
 186     return qio_channel_readv_full(ioc, &iov, 1, NULL, NULL, errp);
 187 }
 188
 189
 190 ssize_t qio_channel_write(QIOChannel *ioc,
 191                           const char *buf,
 192                           size_t buflen,
 193                           Error **errp)
 194 {
 195     struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };
 196     return qio_channel_writev_full(ioc, &iov, 1, NULL, 0, errp);
 197 }
 198
 199
 200 int qio_channel_read_all(QIOChannel *ioc,
 201                          char *buf,
 202                          size_t buflen,
 203                          Error **errp)
 204 {
 205     struct iovec iov = { .iov_base = buf, .iov_len = buflen };
 206     return qio_channel_readv_all(ioc, &iov, 1, errp);
 207 }
 208
 209
 210 int qio_channel_write_all(QIOChannel *ioc,
 211                           const char *buf,
 212                           size_t buflen,
 213                           Error **errp)
 214 {
 215     struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };
 216     return qio_channel_writev_all(ioc, &iov, 1, errp);
 217 }
 218
 219
 220 int qio_channel_set_blocking(QIOChannel *ioc,
 221                               bool enabled,
 222                               Error **errp)
 223 {
 224     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 225     return klass->io_set_blocking(ioc, enabled, errp);
 226 }
 227
 228
 229 int qio_channel_close(QIOChannel *ioc,
 230                       Error **errp)
 231 {
 232     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 233     return klass->io_close(ioc, errp);
 234 }
 235
 236
 237 GSource *qio_channel_create_watch(QIOChannel *ioc,
 238                                   GIOCondition condition)
 239 {
 240     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 241     GSource *ret = klass->io_create_watch(ioc, condition);
 242
 243     if (ioc->name) {
 244         g_source_set_name(ret, ioc->name);
 245     }
 246
 247     return ret;
 248 }
 249
 250
 251 void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
 252                                     AioContext *ctx,
 253                                     IOHandler *io_read,
 254                                     IOHandler *io_write,
 255                                     void *opaque)
 256 {
 257     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 258
 259     klass->io_set_aio_fd_handler(ioc, ctx, io_read, io_write, opaque);
 260 }
 261
 262 guint qio_channel_add_watch(QIOChannel *ioc,
 263                             GIOCondition condition,
 264                             QIOChannelFunc func,
 265                             gpointer user_data,
 266                             GDestroyNotify notify)
 267 {
 268     GSource *source;
 269     guint id;
 270
 271     source = qio_channel_create_watch(ioc, condition);
 272
 273     g_source_set_callback(source, (GSourceFunc)func, user_data, notify);
 274
 275     id = g_source_attach(source, NULL);
 276     g_source_unref(source);
 277
 278     return id;
 279 }
 280
 281
 282 int qio_channel_shutdown(QIOChannel *ioc,
 283                          QIOChannelShutdown how,
 284                          Error **errp)
 285 {
 286     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 287
 288     if (!klass->io_shutdown) {
 289         error_setg(errp, "Data path shutdown not supported");
 290         return -1;
 291     }
 292
 293     return klass->io_shutdown(ioc, how, errp);
 294 }
 295
 296
 297 void qio_channel_set_delay(QIOChannel *ioc,
 298                            bool enabled)
 299 {
 300     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 301
 302     if (klass->io_set_delay) {
 303         klass->io_set_delay(ioc, enabled);
 304     }
 305 }
 306
 307
 308 void qio_channel_set_cork(QIOChannel *ioc,
 309                           bool enabled)
 310 {
 311     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 312
 313     if (klass->io_set_cork) {
 314         klass->io_set_cork(ioc, enabled);
 315     }
 316 }
 317
 318
 319 off_t qio_channel_io_seek(QIOChannel *ioc,
 320                           off_t offset,
 321                           int whence,
 322                           Error **errp)
 323 {
 324     QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
 325
 326     if (!klass->io_seek) {
 327         error_setg(errp, "Channel does not support random access");
 328         return -1;
 329     }
 330
 331     return klass->io_seek(ioc, offset, whence, errp);
 332 }
 333
 334
 335 static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc);
 336
 337 static void qio_channel_restart_read(void *opaque)
 338 {
 339     QIOChannel *ioc = opaque;
 340     Coroutine *co = ioc->read_coroutine;
 341
 342     ioc->read_coroutine = NULL;
 343     qio_channel_set_aio_fd_handlers(ioc);
 344     aio_co_wake(co);
 345 }
 346
 347 static void qio_channel_restart_write(void *opaque)
 348 {
 349     QIOChannel *ioc = opaque;
 350     Coroutine *co = ioc->write_coroutine;
 351
 352     ioc->write_coroutine = NULL;
 353     qio_channel_set_aio_fd_handlers(ioc);
 354     aio_co_wake(co);
 355 }
 356
 357 static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc)
 358 {
 359     IOHandler *rd_handler = NULL, *wr_handler = NULL;
 360     AioContext *ctx;
 361
 362     if (ioc->read_coroutine) {
 363         rd_handler = qio_channel_restart_read;
 364     }
 365     if (ioc->write_coroutine) {
 366         wr_handler = qio_channel_restart_write;
 367     }
 368
 369     ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context();
 370     qio_channel_set_aio_fd_handler(ioc, ctx, rd_handler, wr_handler, ioc);
 371 }
 372
 373 void qio_channel_attach_aio_context(QIOChannel *ioc,
 374                                     AioContext *ctx)
 375 {
 376     assert(!ioc->read_coroutine);
 377     assert(!ioc->write_coroutine);
 378     ioc->ctx = ctx;
 379 }
 380
 381 void qio_channel_detach_aio_context(QIOChannel *ioc)
 382 {
 383     ioc->read_coroutine = NULL;
 384     ioc->write_coroutine = NULL;
 385     qio_channel_set_aio_fd_handlers(ioc);
 386     ioc->ctx = NULL;
 387 }
 388
 389 void coroutine_fn qio_channel_yield(QIOChannel *ioc,
 390                                     GIOCondition condition)
 391 {
 392     assert(qemu_in_coroutine());
 393     if (condition == G_IO_IN) {
 394         assert(!ioc->read_coroutine);
 395         ioc->read_coroutine = qemu_coroutine_self();
 396     } else if (condition == G_IO_OUT) {
 397         assert(!ioc->write_coroutine);
 398         ioc->write_coroutine = qemu_coroutine_self();
 399     } else {
 400         abort();
 401     }
 402     qio_channel_set_aio_fd_handlers(ioc);
 403     qemu_coroutine_yield();
 404 }
 405
 406
 407 static gboolean qio_channel_wait_complete(QIOChannel *ioc,
 408                                           GIOCondition condition,
 409                                           gpointer opaque)
 410 {
 411     GMainLoop *loop = opaque;
 412
 413     g_main_loop_quit(loop);
 414     return FALSE;
 415 }
 416
 417
 418 void qio_channel_wait(QIOChannel *ioc,
 419                       GIOCondition condition)
 420 {
 421     GMainContext *ctxt = g_main_context_new();
 422     GMainLoop *loop = g_main_loop_new(ctxt, TRUE);
 423     GSource *source;
 424
 425     source = qio_channel_create_watch(ioc, condition);
 426
 427     g_source_set_callback(source,
 428                           (GSourceFunc)qio_channel_wait_complete,
 429                           loop,
 430                           NULL);
 431
 432     g_source_attach(source, ctxt);
 433
 434     g_main_loop_run(loop);
 435
 436     g_source_unref(source);
 437     g_main_loop_unref(loop);
 438     g_main_context_unref(ctxt);
 439 }
 440
 441
 442 static void qio_channel_finalize(Object *obj)
 443 {
 444     QIOChannel *ioc = QIO_CHANNEL(obj);
 445
 446     g_free(ioc->name);
 447
 448 #ifdef _WIN32
 449     if (ioc->event) {
 450         CloseHandle(ioc->event);
 451     }
 452 #endif
 453 }
 454
 455 static const TypeInfo qio_channel_info = {
 456     .parent = TYPE_OBJECT,
 457     .name = TYPE_QIO_CHANNEL,
 458     .instance_size = sizeof(QIOChannel),
 459     .instance_finalize = qio_channel_finalize,
 460     .abstract = true,
 461     .class_size = sizeof(QIOChannelClass),
 462 };
 463
 464
 465 static void qio_channel_register_types(void)
 466 {
 467     type_register_static(&qio_channel_info);
 468 }
 469
 470
 471 type_init(qio_channel_register_types);