nbd/server.c

   1 /*
   2  *  Copyright (C) 2016 Red Hat, Inc.
   3  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
   4  *
   5  *  Network Block Device Server Side
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; under version 2 of the License.
  10  *
  11  *  This program 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
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "qemu/osdep.h"
  21 #include "qapi/error.h"
  22 #include "nbd-internal.h"
  23
  24 static int system_errno_to_nbd_errno(int err)
  25 {
  26     switch (err) {
  27     case 0:
  28         return NBD_SUCCESS;
  29     case EPERM:
  30     case EROFS:
  31         return NBD_EPERM;
  32     case EIO:
  33         return NBD_EIO;
  34     case ENOMEM:
  35         return NBD_ENOMEM;
  36 #ifdef EDQUOT
  37     case EDQUOT:
  38 #endif
  39     case EFBIG:
  40     case ENOSPC:
  41         return NBD_ENOSPC;
  42     case ESHUTDOWN:
  43         return NBD_ESHUTDOWN;
  44     case EINVAL:
  45     default:
  46         return NBD_EINVAL;
  47     }
  48 }
  49
  50 /* Definitions for opaque data types */
  51
  52 typedef struct NBDRequestData NBDRequestData;
  53
  54 struct NBDRequestData {
  55     QSIMPLEQ_ENTRY(NBDRequestData) entry;
  56     NBDClient *client;
  57     uint8_t *data;
  58     bool complete;
  59 };
  60
  61 struct NBDExport {
  62     int refcount;
  63     void (*close)(NBDExport *exp);
  64
  65     BlockBackend *blk;
  66     char *name;
  67     char *description;
  68     off_t dev_offset;
  69     off_t size;
  70     uint16_t nbdflags;
  71     QTAILQ_HEAD(, NBDClient) clients;
  72     QTAILQ_ENTRY(NBDExport) next;
  73
  74     AioContext *ctx;
  75
  76     BlockBackend *eject_notifier_blk;
  77     Notifier eject_notifier;
  78 };
  79
  80 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
  81
  82 struct NBDClient {
  83     int refcount;
  84     void (*close)(NBDClient *client);
  85
  86     bool no_zeroes;
  87     NBDExport *exp;
  88     QCryptoTLSCreds *tlscreds;
  89     char *tlsaclname;
  90     QIOChannelSocket *sioc; /* The underlying data channel */
  91     QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
  92
  93     Coroutine *recv_coroutine;
  94
  95     CoMutex send_lock;
  96     Coroutine *send_coroutine;
  97
  98     bool can_read;
  99
 100     QTAILQ_ENTRY(NBDClient) next;
 101     int nb_requests;
 102     bool closing;
 103 };
 104
 105 /* That's all folks */
 106
 107 static void nbd_set_handlers(NBDClient *client);
 108 static void nbd_unset_handlers(NBDClient *client);
 109 static void nbd_update_can_read(NBDClient *client);
 110
 111 static gboolean nbd_negotiate_continue(QIOChannel *ioc,
 112                                        GIOCondition condition,
 113                                        void *opaque)
 114 {
 115     qemu_coroutine_enter(opaque);
 116     return TRUE;
 117 }
 118
 119 static ssize_t nbd_negotiate_read(QIOChannel *ioc, void *buffer, size_t size)
 120 {
 121     ssize_t ret;
 122     guint watch;
 123
 124     assert(qemu_in_coroutine());
 125     /* Negotiation are always in main loop. */
 126     watch = qio_channel_add_watch(ioc,
 127                                   G_IO_IN,
 128                                   nbd_negotiate_continue,
 129                                   qemu_coroutine_self(),
 130                                   NULL);
 131     ret = read_sync(ioc, buffer, size);
 132     g_source_remove(watch);
 133     return ret;
 134
 135 }
 136
 137 static ssize_t nbd_negotiate_write(QIOChannel *ioc, const void *buffer,
 138                                    size_t size)
 139 {
 140     ssize_t ret;
 141     guint watch;
 142
 143     assert(qemu_in_coroutine());
 144     /* Negotiation are always in main loop. */
 145     watch = qio_channel_add_watch(ioc,
 146                                   G_IO_OUT,
 147                                   nbd_negotiate_continue,
 148                                   qemu_coroutine_self(),
 149                                   NULL);
 150     ret = write_sync(ioc, buffer, size);
 151     g_source_remove(watch);
 152     return ret;
 153 }
 154
 155 static ssize_t nbd_negotiate_drop_sync(QIOChannel *ioc, size_t size)
 156 {
 157     ssize_t ret, dropped = size;
 158     uint8_t *buffer = g_malloc(MIN(65536, size));
 159
 160     while (size > 0) {
 161         ret = nbd_negotiate_read(ioc, buffer, MIN(65536, size));
 162         if (ret < 0) {
 163             g_free(buffer);
 164             return ret;
 165         }
 166
 167         assert(ret <= size);
 168         size -= ret;
 169     }
 170
 171     g_free(buffer);
 172     return dropped;
 173 }
 174
 175 /* Basic flow for negotiation
 176
 177    Server         Client
 178    Negotiate
 179
 180    or
 181
 182    Server         Client
 183    Negotiate #1
 184                   Option
 185    Negotiate #2
 186
 187    ----
 188
 189    followed by
 190
 191    Server         Client
 192                   Request
 193    Response
 194                   Request
 195    Response
 196                   ...
 197    ...
 198                   Request (type == 2)
 199
 200 */
 201
 202 /* Send a reply header, including length, but no payload.
 203  * Return -errno on error, 0 on success. */
 204 static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
 205                                       uint32_t opt, uint32_t len)
 206 {
 207     uint64_t magic;
 208
 209     TRACE("Reply opt=%" PRIx32 " type=%" PRIx32 " len=%" PRIu32,
 210           type, opt, len);
 211
 212     magic = cpu_to_be64(NBD_REP_MAGIC);
 213     if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
 214         LOG("write failed (rep magic)");
 215         return -EINVAL;
 216     }
 217     opt = cpu_to_be32(opt);
 218     if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
 219         LOG("write failed (rep opt)");
 220         return -EINVAL;
 221     }
 222     type = cpu_to_be32(type);
 223     if (nbd_negotiate_write(ioc, &type, sizeof(type)) != sizeof(type)) {
 224         LOG("write failed (rep type)");
 225         return -EINVAL;
 226     }
 227     len = cpu_to_be32(len);
 228     if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
 229         LOG("write failed (rep data length)");
 230         return -EINVAL;
 231     }
 232     return 0;
 233 }
 234
 235 /* Send a reply header with default 0 length.
 236  * Return -errno on error, 0 on success. */
 237 static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
 238 {
 239     return nbd_negotiate_send_rep_len(ioc, type, opt, 0);
 240 }
 241
 242 /* Send an error reply.
 243  * Return -errno on error, 0 on success. */
 244 static int GCC_FMT_ATTR(4, 5)
 245 nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type,
 246                            uint32_t opt, const char *fmt, ...)
 247 {
 248     va_list va;
 249     char *msg;
 250     int ret;
 251     size_t len;
 252
 253     va_start(va, fmt);
 254     msg = g_strdup_vprintf(fmt, va);
 255     va_end(va);
 256     len = strlen(msg);
 257     assert(len < 4096);
 258     TRACE("sending error message \"%s\"", msg);
 259     ret = nbd_negotiate_send_rep_len(ioc, type, opt, len);
 260     if (ret < 0) {
 261         goto out;
 262     }
 263     if (nbd_negotiate_write(ioc, msg, len) != len) {
 264         LOG("write failed (error message)");
 265         ret = -EIO;
 266     } else {
 267         ret = 0;
 268     }
 269 out:
 270     g_free(msg);
 271     return ret;
 272 }
 273
 274 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
 275  * Return -errno on error, 0 on success. */
 276 static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
 277 {
 278     size_t name_len, desc_len;
 279     uint32_t len;
 280     const char *name = exp->name ? exp->name : "";
 281     const char *desc = exp->description ? exp->description : "";
 282     int rc;
 283
 284     TRACE("Advertising export name '%s' description '%s'", name, desc);
 285     name_len = strlen(name);
 286     desc_len = strlen(desc);
 287     len = name_len + desc_len + sizeof(len);
 288     rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len);
 289     if (rc < 0) {
 290         return rc;
 291     }
 292
 293     len = cpu_to_be32(name_len);
 294     if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
 295         LOG("write failed (name length)");
 296         return -EINVAL;
 297     }
 298     if (nbd_negotiate_write(ioc, name, name_len) != name_len) {
 299         LOG("write failed (name buffer)");
 300         return -EINVAL;
 301     }
 302     if (nbd_negotiate_write(ioc, desc, desc_len) != desc_len) {
 303         LOG("write failed (description buffer)");
 304         return -EINVAL;
 305     }
 306     return 0;
 307 }
 308
 309 /* Process the NBD_OPT_LIST command, with a potential series of replies.
 310  * Return -errno on error, 0 on success. */
 311 static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length)
 312 {
 313     NBDExport *exp;
 314
 315     if (length) {
 316         if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
 317             return -EIO;
 318         }
 319         return nbd_negotiate_send_rep_err(client->ioc,
 320                                           NBD_REP_ERR_INVALID, NBD_OPT_LIST,
 321                                           "OPT_LIST should not have length");
 322     }
 323
 324     /* For each export, send a NBD_REP_SERVER reply. */
 325     QTAILQ_FOREACH(exp, &exports, next) {
 326         if (nbd_negotiate_send_rep_list(client->ioc, exp)) {
 327             return -EINVAL;
 328         }
 329     }
 330     /* Finish with a NBD_REP_ACK. */
 331     return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST);
 332 }
 333
 334 static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length)
 335 {
 336     int rc = -EINVAL;
 337     char name[NBD_MAX_NAME_SIZE + 1];
 338
 339     /* Client sends:
 340         [20 ..  xx]   export name (length bytes)
 341      */
 342     TRACE("Checking length");
 343     if (length >= sizeof(name)) {
 344         LOG("Bad length received");
 345         goto fail;
 346     }
 347     if (nbd_negotiate_read(client->ioc, name, length) != length) {
 348         LOG("read failed");
 349         goto fail;
 350     }
 351     name[length] = '\0';
 352
 353     TRACE("Client requested export '%s'", name);
 354
 355     client->exp = nbd_export_find(name);
 356     if (!client->exp) {
 357         LOG("export not found");
 358         goto fail;
 359     }
 360
 361     QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
 362     nbd_export_get(client->exp);
 363     rc = 0;
 364 fail:
 365     return rc;
 366 }
 367
 368 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
 369  * new channel for all further (now-encrypted) communication. */
 370 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
 371                                                  uint32_t length)
 372 {
 373     QIOChannel *ioc;
 374     QIOChannelTLS *tioc;
 375     struct NBDTLSHandshakeData data = { 0 };
 376
 377     TRACE("Setting up TLS");
 378     ioc = client->ioc;
 379     if (length) {
 380         if (nbd_negotiate_drop_sync(ioc, length) != length) {
 381             return NULL;
 382         }
 383         nbd_negotiate_send_rep_err(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS,
 384                                    "OPT_STARTTLS should not have length");
 385         return NULL;
 386     }
 387
 388     if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK,
 389                                NBD_OPT_STARTTLS) < 0) {
 390         return NULL;
 391     }
 392
 393     tioc = qio_channel_tls_new_server(ioc,
 394                                       client->tlscreds,
 395                                       client->tlsaclname,
 396                                       NULL);
 397     if (!tioc) {
 398         return NULL;
 399     }
 400
 401     qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
 402     TRACE("Starting TLS handshake");
 403     data.loop = g_main_loop_new(g_main_context_default(), FALSE);
 404     qio_channel_tls_handshake(tioc,
 405                               nbd_tls_handshake,
 406                               &data,
 407                               NULL);
 408
 409     if (!data.complete) {
 410         g_main_loop_run(data.loop);
 411     }
 412     g_main_loop_unref(data.loop);
 413     if (data.error) {
 414         object_unref(OBJECT(tioc));
 415         error_free(data.error);
 416         return NULL;
 417     }
 418
 419     return QIO_CHANNEL(tioc);
 420 }
 421
 422
 423 /* Process all NBD_OPT_* client option commands.
 424  * Return -errno on error, 0 on success. */
 425 static int nbd_negotiate_options(NBDClient *client)
 426 {
 427     uint32_t flags;
 428     bool fixedNewstyle = false;
 429
 430     /* Client sends:
 431         [ 0 ..   3]   client flags
 432
 433         [ 0 ..   7]   NBD_OPTS_MAGIC
 434         [ 8 ..  11]   NBD option
 435         [12 ..  15]   Data length
 436         ...           Rest of request
 437
 438         [ 0 ..   7]   NBD_OPTS_MAGIC
 439         [ 8 ..  11]   Second NBD option
 440         [12 ..  15]   Data length
 441         ...           Rest of request
 442     */
 443
 444     if (nbd_negotiate_read(client->ioc, &flags, sizeof(flags)) !=
 445         sizeof(flags)) {
 446         LOG("read failed");
 447         return -EIO;
 448     }
 449     TRACE("Checking client flags");
 450     be32_to_cpus(&flags);
 451     if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
 452         TRACE("Client supports fixed newstyle handshake");
 453         fixedNewstyle = true;
 454         flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
 455     }
 456     if (flags & NBD_FLAG_C_NO_ZEROES) {
 457         TRACE("Client supports no zeroes at handshake end");
 458         client->no_zeroes = true;
 459         flags &= ~NBD_FLAG_C_NO_ZEROES;
 460     }
 461     if (flags != 0) {
 462         TRACE("Unknown client flags 0x%" PRIx32 " received", flags);
 463         return -EIO;
 464     }
 465
 466     while (1) {
 467         int ret;
 468         uint32_t clientflags, length;
 469         uint64_t magic;
 470
 471         if (nbd_negotiate_read(client->ioc, &magic, sizeof(magic)) !=
 472             sizeof(magic)) {
 473             LOG("read failed");
 474             return -EINVAL;
 475         }
 476         TRACE("Checking opts magic");
 477         if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) {
 478             LOG("Bad magic received");
 479             return -EINVAL;
 480         }
 481
 482         if (nbd_negotiate_read(client->ioc, &clientflags,
 483                                sizeof(clientflags)) != sizeof(clientflags)) {
 484             LOG("read failed");
 485             return -EINVAL;
 486         }
 487         clientflags = be32_to_cpu(clientflags);
 488
 489         if (nbd_negotiate_read(client->ioc, &length, sizeof(length)) !=
 490             sizeof(length)) {
 491             LOG("read failed");
 492             return -EINVAL;
 493         }
 494         length = be32_to_cpu(length);
 495
 496         TRACE("Checking option 0x%" PRIx32, clientflags);
 497         if (client->tlscreds &&
 498             client->ioc == (QIOChannel *)client->sioc) {
 499             QIOChannel *tioc;
 500             if (!fixedNewstyle) {
 501                 TRACE("Unsupported option 0x%" PRIx32, clientflags);
 502                 return -EINVAL;
 503             }
 504             switch (clientflags) {
 505             case NBD_OPT_STARTTLS:
 506                 tioc = nbd_negotiate_handle_starttls(client, length);
 507                 if (!tioc) {
 508                     return -EIO;
 509                 }
 510                 object_unref(OBJECT(client->ioc));
 511                 client->ioc = QIO_CHANNEL(tioc);
 512                 break;
 513
 514             case NBD_OPT_EXPORT_NAME:
 515                 /* No way to return an error to client, so drop connection */
 516                 TRACE("Option 0x%x not permitted before TLS", clientflags);
 517                 return -EINVAL;
 518
 519             default:
 520                 if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
 521                     return -EIO;
 522                 }
 523                 ret = nbd_negotiate_send_rep_err(client->ioc,
 524                                                  NBD_REP_ERR_TLS_REQD,
 525                                                  clientflags,
 526                                                  "Option 0x%" PRIx32
 527                                                  "not permitted before TLS",
 528                                                  clientflags);
 529                 if (ret < 0) {
 530                     return ret;
 531                 }
 532                 /* Let the client keep trying, unless they asked to quit */
 533                 if (clientflags == NBD_OPT_ABORT) {
 534                     return -EINVAL;
 535                 }
 536                 break;
 537             }
 538         } else if (fixedNewstyle) {
 539             switch (clientflags) {
 540             case NBD_OPT_LIST:
 541                 ret = nbd_negotiate_handle_list(client, length);
 542                 if (ret < 0) {
 543                     return ret;
 544                 }
 545                 break;
 546
 547             case NBD_OPT_ABORT:
 548                 /* NBD spec says we must try to reply before
 549                  * disconnecting, but that we must also tolerate
 550                  * guests that don't wait for our reply. */
 551                 nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, clientflags);
 552                 return -EINVAL;
 553
 554             case NBD_OPT_EXPORT_NAME:
 555                 return nbd_negotiate_handle_export_name(client, length);
 556
 557             case NBD_OPT_STARTTLS:
 558                 if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
 559                     return -EIO;
 560                 }
 561                 if (client->tlscreds) {
 562                     ret = nbd_negotiate_send_rep_err(client->ioc,
 563                                                      NBD_REP_ERR_INVALID,
 564                                                      clientflags,
 565                                                      "TLS already enabled");
 566                 } else {
 567                     ret = nbd_negotiate_send_rep_err(client->ioc,
 568                                                      NBD_REP_ERR_POLICY,
 569                                                      clientflags,
 570                                                      "TLS not configured");
 571                 }
 572                 if (ret < 0) {
 573                     return ret;
 574                 }
 575                 break;
 576             default:
 577                 if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
 578                     return -EIO;
 579                 }
 580                 ret = nbd_negotiate_send_rep_err(client->ioc,
 581                                                  NBD_REP_ERR_UNSUP,
 582                                                  clientflags,
 583                                                  "Unsupported option 0x%"
 584                                                  PRIx32,
 585                                                  clientflags);
 586                 if (ret < 0) {
 587                     return ret;
 588                 }
 589                 break;
 590             }
 591         } else {
 592             /*
 593              * If broken new-style we should drop the connection
 594              * for anything except NBD_OPT_EXPORT_NAME
 595              */
 596             switch (clientflags) {
 597             case NBD_OPT_EXPORT_NAME:
 598                 return nbd_negotiate_handle_export_name(client, length);
 599
 600             default:
 601                 TRACE("Unsupported option 0x%" PRIx32, clientflags);
 602                 return -EINVAL;
 603             }
 604         }
 605     }
 606 }
 607
 608 typedef struct {
 609     NBDClient *client;
 610     Coroutine *co;
 611 } NBDClientNewData;
 612
 613 static coroutine_fn int nbd_negotiate(NBDClientNewData *data)
 614 {
 615     NBDClient *client = data->client;
 616     char buf[8 + 8 + 8 + 128];
 617     int rc;
 618     const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
 619                               NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |
 620                               NBD_FLAG_SEND_WRITE_ZEROES);
 621     bool oldStyle;
 622     size_t len;
 623
 624     /* Old style negotiation header without options
 625         [ 0 ..   7]   passwd       ("NBDMAGIC")
 626         [ 8 ..  15]   magic        (NBD_CLIENT_MAGIC)
 627         [16 ..  23]   size
 628         [24 ..  25]   server flags (0)
 629         [26 ..  27]   export flags
 630         [28 .. 151]   reserved     (0)
 631
 632        New style negotiation header with options
 633         [ 0 ..   7]   passwd       ("NBDMAGIC")
 634         [ 8 ..  15]   magic        (NBD_OPTS_MAGIC)
 635         [16 ..  17]   server flags (0)
 636         ....options sent....
 637         [18 ..  25]   size
 638         [26 ..  27]   export flags
 639         [28 .. 151]   reserved     (0, omit if no_zeroes)
 640      */
 641
 642     qio_channel_set_blocking(client->ioc, false, NULL);
 643     rc = -EINVAL;
 644
 645     TRACE("Beginning negotiation.");
 646     memset(buf, 0, sizeof(buf));
 647     memcpy(buf, "NBDMAGIC", 8);
 648
 649     oldStyle = client->exp != NULL && !client->tlscreds;
 650     if (oldStyle) {
 651         TRACE("advertising size %" PRIu64 " and flags %x",
 652               client->exp->size, client->exp->nbdflags | myflags);
 653         stq_be_p(buf + 8, NBD_CLIENT_MAGIC);
 654         stq_be_p(buf + 16, client->exp->size);
 655         stw_be_p(buf + 26, client->exp->nbdflags | myflags);
 656     } else {
 657         stq_be_p(buf + 8, NBD_OPTS_MAGIC);
 658         stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
 659     }
 660
 661     if (oldStyle) {
 662         if (client->tlscreds) {
 663             TRACE("TLS cannot be enabled with oldstyle protocol");
 664             goto fail;
 665         }
 666         if (nbd_negotiate_write(client->ioc, buf, sizeof(buf)) != sizeof(buf)) {
 667             LOG("write failed");
 668             goto fail;
 669         }
 670     } else {
 671         if (nbd_negotiate_write(client->ioc, buf, 18) != 18) {
 672             LOG("write failed");
 673             goto fail;
 674         }
 675         rc = nbd_negotiate_options(client);
 676         if (rc != 0) {
 677             LOG("option negotiation failed");
 678             goto fail;
 679         }
 680
 681         TRACE("advertising size %" PRIu64 " and flags %x",
 682               client->exp->size, client->exp->nbdflags | myflags);
 683         stq_be_p(buf + 18, client->exp->size);
 684         stw_be_p(buf + 26, client->exp->nbdflags | myflags);
 685         len = client->no_zeroes ? 10 : sizeof(buf) - 18;
 686         if (nbd_negotiate_write(client->ioc, buf + 18, len) != len) {
 687             LOG("write failed");
 688             goto fail;
 689         }
 690     }
 691
 692     TRACE("Negotiation succeeded.");
 693     rc = 0;
 694 fail:
 695     return rc;
 696 }
 697
 698 static ssize_t nbd_receive_request(QIOChannel *ioc, NBDRequest *request)
 699 {
 700     uint8_t buf[NBD_REQUEST_SIZE];
 701     uint32_t magic;
 702     ssize_t ret;
 703
 704     ret = read_sync(ioc, buf, sizeof(buf));
 705     if (ret < 0) {
 706         return ret;
 707     }
 708
 709     if (ret != sizeof(buf)) {
 710         LOG("read failed");
 711         return -EINVAL;
 712     }
 713
 714     /* Request
 715        [ 0 ..  3]   magic   (NBD_REQUEST_MAGIC)
 716        [ 4 ..  5]   flags   (NBD_CMD_FLAG_FUA, ...)
 717        [ 6 ..  7]   type    (NBD_CMD_READ, ...)
 718        [ 8 .. 15]   handle
 719        [16 .. 23]   from
 720        [24 .. 27]   len
 721      */
 722
 723     magic = ldl_be_p(buf);
 724     request->flags  = lduw_be_p(buf + 4);
 725     request->type   = lduw_be_p(buf + 6);
 726     request->handle = ldq_be_p(buf + 8);
 727     request->from   = ldq_be_p(buf + 16);
 728     request->len    = ldl_be_p(buf + 24);
 729
 730     TRACE("Got request: { magic = 0x%" PRIx32 ", .flags = %" PRIx16
 731           ", .type = %" PRIx16 ", from = %" PRIu64 ", len = %" PRIu32 " }",
 732           magic, request->flags, request->type, request->from, request->len);
 733
 734     if (magic != NBD_REQUEST_MAGIC) {
 735         LOG("invalid magic (got 0x%" PRIx32 ")", magic);
 736         return -EINVAL;
 737     }
 738     return 0;
 739 }
 740
 741 static ssize_t nbd_send_reply(QIOChannel *ioc, NBDReply *reply)
 742 {
 743     uint8_t buf[NBD_REPLY_SIZE];
 744     ssize_t ret;
 745
 746     reply->error = system_errno_to_nbd_errno(reply->error);
 747
 748     TRACE("Sending response to client: { .error = %" PRId32
 749           ", handle = %" PRIu64 " }",
 750           reply->error, reply->handle);
 751
 752     /* Reply
 753        [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
 754        [ 4 ..  7]    error   (0 == no error)
 755        [ 7 .. 15]    handle
 756      */
 757     stl_be_p(buf, NBD_REPLY_MAGIC);
 758     stl_be_p(buf + 4, reply->error);
 759     stq_be_p(buf + 8, reply->handle);
 760
 761     ret = write_sync(ioc, buf, sizeof(buf));
 762     if (ret < 0) {
 763         return ret;
 764     }
 765
 766     if (ret != sizeof(buf)) {
 767         LOG("writing to socket failed");
 768         return -EINVAL;
 769     }
 770     return 0;
 771 }
 772
 773 #define MAX_NBD_REQUESTS 16
 774
 775 void nbd_client_get(NBDClient *client)
 776 {
 777     client->refcount++;
 778 }
 779
 780 void nbd_client_put(NBDClient *client)
 781 {
 782     if (--client->refcount == 0) {
 783         /* The last reference should be dropped by client->close,
 784          * which is called by client_close.
 785          */
 786         assert(client->closing);
 787
 788         nbd_unset_handlers(client);
 789         object_unref(OBJECT(client->sioc));
 790         object_unref(OBJECT(client->ioc));
 791         if (client->tlscreds) {
 792             object_unref(OBJECT(client->tlscreds));
 793         }
 794         g_free(client->tlsaclname);
 795         if (client->exp) {
 796             QTAILQ_REMOVE(&client->exp->clients, client, next);
 797             nbd_export_put(client->exp);
 798         }
 799         g_free(client);
 800     }
 801 }
 802
 803 static void client_close(NBDClient *client)
 804 {
 805     if (client->closing) {
 806         return;
 807     }
 808
 809     client->closing = true;
 810
 811     /* Force requests to finish.  They will drop their own references,
 812      * then we'll close the socket and free the NBDClient.
 813      */
 814     qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
 815                          NULL);
 816
 817     /* Also tell the client, so that they release their reference.  */
 818     if (client->close) {
 819         client->close(client);
 820     }
 821 }
 822
 823 static NBDRequestData *nbd_request_get(NBDClient *client)
 824 {
 825     NBDRequestData *req;
 826
 827     assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
 828     client->nb_requests++;
 829     nbd_update_can_read(client);
 830
 831     req = g_new0(NBDRequestData, 1);
 832     nbd_client_get(client);
 833     req->client = client;
 834     return req;
 835 }
 836
 837 static void nbd_request_put(NBDRequestData *req)
 838 {
 839     NBDClient *client = req->client;
 840
 841     if (req->data) {
 842         qemu_vfree(req->data);
 843     }
 844     g_free(req);
 845
 846     client->nb_requests--;
 847     nbd_update_can_read(client);
 848     nbd_client_put(client);
 849 }
 850
 851 static void blk_aio_attached(AioContext *ctx, void *opaque)
 852 {
 853     NBDExport *exp = opaque;
 854     NBDClient *client;
 855
 856     TRACE("Export %s: Attaching clients to AIO context %p\n", exp->name, ctx);
 857
 858     exp->ctx = ctx;
 859
 860     QTAILQ_FOREACH(client, &exp->clients, next) {
 861         nbd_set_handlers(client);
 862     }
 863 }
 864
 865 static void blk_aio_detach(void *opaque)
 866 {
 867     NBDExport *exp = opaque;
 868     NBDClient *client;
 869
 870     TRACE("Export %s: Detaching clients from AIO context %p\n", exp->name, exp->ctx);
 871
 872     QTAILQ_FOREACH(client, &exp->clients, next) {
 873         nbd_unset_handlers(client);
 874     }
 875
 876     exp->ctx = NULL;
 877 }
 878
 879 static void nbd_eject_notifier(Notifier *n, void *data)
 880 {
 881     NBDExport *exp = container_of(n, NBDExport, eject_notifier);
 882     nbd_export_close(exp);
 883 }
 884
 885 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
 886                           uint16_t nbdflags, void (*close)(NBDExport *),
 887                           bool writethrough, BlockBackend *on_eject_blk,
 888                           Error **errp)
 889 {
 890     BlockBackend *blk;
 891     NBDExport *exp = g_malloc0(sizeof(NBDExport));
 892
 893     blk = blk_new();
 894     blk_insert_bs(blk, bs);
 895     blk_set_enable_write_cache(blk, !writethrough);
 896
 897     exp->refcount = 1;
 898     QTAILQ_INIT(&exp->clients);
 899     exp->blk = blk;
 900     exp->dev_offset = dev_offset;
 901     exp->nbdflags = nbdflags;
 902     exp->size = size < 0 ? blk_getlength(blk) : size;
 903     if (exp->size < 0) {
 904         error_setg_errno(errp, -exp->size,
 905                          "Failed to determine the NBD export's length");
 906         goto fail;
 907     }
 908     exp->size -= exp->size % BDRV_SECTOR_SIZE;
 909
 910     exp->close = close;
 911     exp->ctx = blk_get_aio_context(blk);
 912     blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
 913
 914     if (on_eject_blk) {
 915         blk_ref(on_eject_blk);
 916         exp->eject_notifier_blk = on_eject_blk;
 917         exp->eject_notifier.notify = nbd_eject_notifier;
 918         blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
 919     }
 920
 921     /*
 922      * NBD exports are used for non-shared storage migration.  Make sure
 923      * that BDRV_O_INACTIVE is cleared and the image is ready for write
 924      * access since the export could be available before migration handover.
 925      */
 926     aio_context_acquire(exp->ctx);
 927     blk_invalidate_cache(blk, NULL);
 928     aio_context_release(exp->ctx);
 929     return exp;
 930
 931 fail:
 932     blk_unref(blk);
 933     g_free(exp);
 934     return NULL;
 935 }
 936
 937 NBDExport *nbd_export_find(const char *name)
 938 {
 939     NBDExport *exp;
 940     QTAILQ_FOREACH(exp, &exports, next) {
 941         if (strcmp(name, exp->name) == 0) {
 942             return exp;
 943         }
 944     }
 945
 946     return NULL;
 947 }
 948
 949 void nbd_export_set_name(NBDExport *exp, const char *name)
 950 {
 951     if (exp->name == name) {
 952         return;
 953     }
 954
 955     nbd_export_get(exp);
 956     if (exp->name != NULL) {
 957         g_free(exp->name);
 958         exp->name = NULL;
 959         QTAILQ_REMOVE(&exports, exp, next);
 960         nbd_export_put(exp);
 961     }
 962     if (name != NULL) {
 963         nbd_export_get(exp);
 964         exp->name = g_strdup(name);
 965         QTAILQ_INSERT_TAIL(&exports, exp, next);
 966     }
 967     nbd_export_put(exp);
 968 }
 969
 970 void nbd_export_set_description(NBDExport *exp, const char *description)
 971 {
 972     g_free(exp->description);
 973     exp->description = g_strdup(description);
 974 }
 975
 976 void nbd_export_close(NBDExport *exp)
 977 {
 978     NBDClient *client, *next;
 979
 980     nbd_export_get(exp);
 981     QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
 982         client_close(client);
 983     }
 984     nbd_export_set_name(exp, NULL);
 985     nbd_export_set_description(exp, NULL);
 986     nbd_export_put(exp);
 987 }
 988
 989 void nbd_export_get(NBDExport *exp)
 990 {
 991     assert(exp->refcount > 0);
 992     exp->refcount++;
 993 }
 994
 995 void nbd_export_put(NBDExport *exp)
 996 {
 997     assert(exp->refcount > 0);
 998     if (exp->refcount == 1) {
 999         nbd_export_close(exp);
1000     }
1001
1002     if (--exp->refcount == 0) {
1003         assert(exp->name == NULL);
1004         assert(exp->description == NULL);
1005
1006         if (exp->close) {
1007             exp->close(exp);
1008         }
1009
1010         if (exp->blk) {
1011             if (exp->eject_notifier_blk) {
1012                 notifier_remove(&exp->eject_notifier);
1013                 blk_unref(exp->eject_notifier_blk);
1014             }
1015             blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
1016                                             blk_aio_detach, exp);
1017             blk_unref(exp->blk);
1018             exp->blk = NULL;
1019         }
1020
1021         g_free(exp);
1022     }
1023 }
1024
1025 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
1026 {
1027     return exp->blk;
1028 }
1029
1030 void nbd_export_close_all(void)
1031 {
1032     NBDExport *exp, *next;
1033
1034     QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
1035         nbd_export_close(exp);
1036     }
1037 }
1038
1039 static ssize_t nbd_co_send_reply(NBDRequestData *req, NBDReply *reply,
1040                                  int len)
1041 {
1042     NBDClient *client = req->client;
1043     ssize_t rc, ret;
1044
1045     g_assert(qemu_in_coroutine());
1046     qemu_co_mutex_lock(&client->send_lock);
1047     client->send_coroutine = qemu_coroutine_self();
1048     nbd_set_handlers(client);
1049
1050     if (!len) {
1051         rc = nbd_send_reply(client->ioc, reply);
1052     } else {
1053         qio_channel_set_cork(client->ioc, true);
1054         rc = nbd_send_reply(client->ioc, reply);
1055         if (rc >= 0) {
1056             ret = write_sync(client->ioc, req->data, len);
1057             if (ret != len) {
1058                 rc = -EIO;
1059             }
1060         }
1061         qio_channel_set_cork(client->ioc, false);
1062     }
1063
1064     client->send_coroutine = NULL;
1065     nbd_set_handlers(client);
1066     qemu_co_mutex_unlock(&client->send_lock);
1067     return rc;
1068 }
1069
1070 /* Collect a client request.  Return 0 if request looks valid, -EAGAIN
1071  * to keep trying the collection, -EIO to drop connection right away,
1072  * and any other negative value to report an error to the client
1073  * (although the caller may still need to disconnect after reporting
1074  * the error).  */
1075 static ssize_t nbd_co_receive_request(NBDRequestData *req,
1076                                       NBDRequest *request)
1077 {
1078     NBDClient *client = req->client;
1079     ssize_t rc;
1080
1081     g_assert(qemu_in_coroutine());
1082     client->recv_coroutine = qemu_coroutine_self();
1083     nbd_update_can_read(client);
1084
1085     rc = nbd_receive_request(client->ioc, request);
1086     if (rc < 0) {
1087         if (rc != -EAGAIN) {
1088             rc = -EIO;
1089         }
1090         goto out;
1091     }
1092
1093     TRACE("Decoding type");
1094
1095     if (request->type != NBD_CMD_WRITE) {
1096         /* No payload, we are ready to read the next request.  */
1097         req->complete = true;
1098     }
1099
1100     if (request->type == NBD_CMD_DISC) {
1101         /* Special case: we're going to disconnect without a reply,
1102          * whether or not flags, from, or len are bogus */
1103         TRACE("Request type is DISCONNECT");
1104         rc = -EIO;
1105         goto out;
1106     }
1107
1108     /* Check for sanity in the parameters, part 1.  Defer as many
1109      * checks as possible until after reading any NBD_CMD_WRITE
1110      * payload, so we can try and keep the connection alive.  */
1111     if ((request->from + request->len) < request->from) {
1112         LOG("integer overflow detected, you're probably being attacked");
1113         rc = -EINVAL;
1114         goto out;
1115     }
1116
1117     if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) {
1118         if (request->len > NBD_MAX_BUFFER_SIZE) {
1119             LOG("len (%" PRIu32" ) is larger than max len (%u)",
1120                 request->len, NBD_MAX_BUFFER_SIZE);
1121             rc = -EINVAL;
1122             goto out;
1123         }
1124
1125         req->data = blk_try_blockalign(client->exp->blk, request->len);
1126         if (req->data == NULL) {
1127             rc = -ENOMEM;
1128             goto out;
1129         }
1130     }
1131     if (request->type == NBD_CMD_WRITE) {
1132         TRACE("Reading %" PRIu32 " byte(s)", request->len);
1133
1134         if (read_sync(client->ioc, req->data, request->len) != request->len) {
1135             LOG("reading from socket failed");
1136             rc = -EIO;
1137             goto out;
1138         }
1139         req->complete = true;
1140     }
1141
1142     /* Sanity checks, part 2. */
1143     if (request->from + request->len > client->exp->size) {
1144         LOG("operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
1145             ", Size: %" PRIu64, request->from, request->len,
1146             (uint64_t)client->exp->size);
1147         rc = request->type == NBD_CMD_WRITE ? -ENOSPC : -EINVAL;
1148         goto out;
1149     }
1150     if (request->flags & ~(NBD_CMD_FLAG_FUA | NBD_CMD_FLAG_NO_HOLE)) {
1151         LOG("unsupported flags (got 0x%x)", request->flags);
1152         rc = -EINVAL;
1153         goto out;
1154     }
1155     if (request->type != NBD_CMD_WRITE_ZEROES &&
1156         (request->flags & NBD_CMD_FLAG_NO_HOLE)) {
1157         LOG("unexpected flags (got 0x%x)", request->flags);
1158         rc = -EINVAL;
1159         goto out;
1160     }
1161
1162     rc = 0;
1163
1164 out:
1165     client->recv_coroutine = NULL;
1166     nbd_update_can_read(client);
1167
1168     return rc;
1169 }
1170
1171 static void nbd_trip(void *opaque)
1172 {
1173     NBDClient *client = opaque;
1174     NBDExport *exp = client->exp;
1175     NBDRequestData *req;
1176     NBDRequest request;
1177     NBDReply reply;
1178     ssize_t ret;
1179     int flags;
1180
1181     TRACE("Reading request.");
1182     if (client->closing) {
1183         return;
1184     }
1185
1186     req = nbd_request_get(client);
1187     ret = nbd_co_receive_request(req, &request);
1188     if (ret == -EAGAIN) {
1189         goto done;
1190     }
1191     if (ret == -EIO) {
1192         goto out;
1193     }
1194
1195     reply.handle = request.handle;
1196     reply.error = 0;
1197
1198     if (ret < 0) {
1199         reply.error = -ret;
1200         goto error_reply;
1201     }
1202
1203     if (client->closing) {
1204         /*
1205          * The client may be closed when we are blocked in
1206          * nbd_co_receive_request()
1207          */
1208         goto done;
1209     }
1210
1211     switch (request.type) {
1212     case NBD_CMD_READ:
1213         TRACE("Request type is READ");
1214
1215         /* XXX: NBD Protocol only documents use of FUA with WRITE */
1216         if (request.flags & NBD_CMD_FLAG_FUA) {
1217             ret = blk_co_flush(exp->blk);
1218             if (ret < 0) {
1219                 LOG("flush failed");
1220                 reply.error = -ret;
1221                 goto error_reply;
1222             }
1223         }
1224
1225         ret = blk_pread(exp->blk, request.from + exp->dev_offset,
1226                         req->data, request.len);
1227         if (ret < 0) {
1228             LOG("reading from file failed");
1229             reply.error = -ret;
1230             goto error_reply;
1231         }
1232
1233         TRACE("Read %" PRIu32" byte(s)", request.len);
1234         if (nbd_co_send_reply(req, &reply, request.len) < 0)
1235             goto out;
1236         break;
1237     case NBD_CMD_WRITE:
1238         TRACE("Request type is WRITE");
1239
1240         if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
1241             TRACE("Server is read-only, return error");
1242             reply.error = EROFS;
1243             goto error_reply;
1244         }
1245
1246         TRACE("Writing to device");
1247
1248         flags = 0;
1249         if (request.flags & NBD_CMD_FLAG_FUA) {
1250             flags |= BDRV_REQ_FUA;
1251         }
1252         ret = blk_pwrite(exp->blk, request.from + exp->dev_offset,
1253                          req->data, request.len, flags);
1254         if (ret < 0) {
1255             LOG("writing to file failed");
1256             reply.error = -ret;
1257             goto error_reply;
1258         }
1259
1260         if (nbd_co_send_reply(req, &reply, 0) < 0) {
1261             goto out;
1262         }
1263         break;
1264
1265     case NBD_CMD_WRITE_ZEROES:
1266         TRACE("Request type is WRITE_ZEROES");
1267
1268         if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
1269             TRACE("Server is read-only, return error");
1270             reply.error = EROFS;
1271             goto error_reply;
1272         }
1273
1274         TRACE("Writing to device");
1275
1276         flags = 0;
1277         if (request.flags & NBD_CMD_FLAG_FUA) {
1278             flags |= BDRV_REQ_FUA;
1279         }
1280         if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) {
1281             flags |= BDRV_REQ_MAY_UNMAP;
1282         }
1283         ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset,
1284                                 request.len, flags);
1285         if (ret < 0) {
1286             LOG("writing to file failed");
1287             reply.error = -ret;
1288             goto error_reply;
1289         }
1290
1291         if (nbd_co_send_reply(req, &reply, 0) < 0) {
1292             goto out;
1293         }
1294         break;
1295
1296     case NBD_CMD_DISC:
1297         /* unreachable, thanks to special case in nbd_co_receive_request() */
1298         abort();
1299
1300     case NBD_CMD_FLUSH:
1301         TRACE("Request type is FLUSH");
1302
1303         ret = blk_co_flush(exp->blk);
1304         if (ret < 0) {
1305             LOG("flush failed");
1306             reply.error = -ret;
1307         }
1308         if (nbd_co_send_reply(req, &reply, 0) < 0) {
1309             goto out;
1310         }
1311         break;
1312     case NBD_CMD_TRIM:
1313         TRACE("Request type is TRIM");
1314         ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset,
1315                               request.len);
1316         if (ret < 0) {
1317             LOG("discard failed");
1318             reply.error = -ret;
1319         }
1320         if (nbd_co_send_reply(req, &reply, 0) < 0) {
1321             goto out;
1322         }
1323         break;
1324     default:
1325         LOG("invalid request type (%" PRIu32 ") received", request.type);
1326         reply.error = EINVAL;
1327     error_reply:
1328         /* We must disconnect after NBD_CMD_WRITE if we did not
1329          * read the payload.
1330          */
1331         if (nbd_co_send_reply(req, &reply, 0) < 0 || !req->complete) {
1332             goto out;
1333         }
1334         break;
1335     }
1336
1337     TRACE("Request/Reply complete");
1338
1339 done:
1340     nbd_request_put(req);
1341     return;
1342
1343 out:
1344     nbd_request_put(req);
1345     client_close(client);
1346 }
1347
1348 static void nbd_read(void *opaque)
1349 {
1350     NBDClient *client = opaque;
1351
1352     if (client->recv_coroutine) {
1353         qemu_coroutine_enter(client->recv_coroutine);
1354     } else {
1355         qemu_coroutine_enter(qemu_coroutine_create(nbd_trip, client));
1356     }
1357 }
1358
1359 static void nbd_restart_write(void *opaque)
1360 {
1361     NBDClient *client = opaque;
1362
1363     qemu_coroutine_enter(client->send_coroutine);
1364 }
1365
1366 static void nbd_set_handlers(NBDClient *client)
1367 {
1368     if (client->exp && client->exp->ctx) {
1369         aio_set_fd_handler(client->exp->ctx, client->sioc->fd,
1370                            true,
1371                            client->can_read ? nbd_read : NULL,
1372                            client->send_coroutine ? nbd_restart_write : NULL,
1373                            client);
1374     }
1375 }
1376
1377 static void nbd_unset_handlers(NBDClient *client)
1378 {
1379     if (client->exp && client->exp->ctx) {
1380         aio_set_fd_handler(client->exp->ctx, client->sioc->fd,
1381                            true, NULL, NULL, NULL);
1382     }
1383 }
1384
1385 static void nbd_update_can_read(NBDClient *client)
1386 {
1387     bool can_read = client->recv_coroutine ||
1388                     client->nb_requests < MAX_NBD_REQUESTS;
1389
1390     if (can_read != client->can_read) {
1391         client->can_read = can_read;
1392         nbd_set_handlers(client);
1393
1394         /* There is no need to invoke aio_notify(), since aio_set_fd_handler()
1395          * in nbd_set_handlers() will have taken care of that */
1396     }
1397 }
1398
1399 static coroutine_fn void nbd_co_client_start(void *opaque)
1400 {
1401     NBDClientNewData *data = opaque;
1402     NBDClient *client = data->client;
1403     NBDExport *exp = client->exp;
1404
1405     if (exp) {
1406         nbd_export_get(exp);
1407     }
1408     if (nbd_negotiate(data)) {
1409         client_close(client);
1410         goto out;
1411     }
1412     qemu_co_mutex_init(&client->send_lock);
1413     nbd_set_handlers(client);
1414
1415     if (exp) {
1416         QTAILQ_INSERT_TAIL(&exp->clients, client, next);
1417     }
1418 out:
1419     g_free(data);
1420 }
1421
1422 void nbd_client_new(NBDExport *exp,
1423                     QIOChannelSocket *sioc,
1424                     QCryptoTLSCreds *tlscreds,
1425                     const char *tlsaclname,
1426                     void (*close_fn)(NBDClient *))
1427 {
1428     NBDClient *client;
1429     NBDClientNewData *data = g_new(NBDClientNewData, 1);
1430
1431     client = g_malloc0(sizeof(NBDClient));
1432     client->refcount = 1;
1433     client->exp = exp;
1434     client->tlscreds = tlscreds;
1435     if (tlscreds) {
1436         object_ref(OBJECT(client->tlscreds));
1437     }
1438     client->tlsaclname = g_strdup(tlsaclname);
1439     client->sioc = sioc;
1440     object_ref(OBJECT(client->sioc));
1441     client->ioc = QIO_CHANNEL(sioc);
1442     object_ref(OBJECT(client->ioc));
1443     client->can_read = true;
1444     client->close = close_fn;
1445
1446     data->client = client;
1447     data->co = qemu_coroutine_create(nbd_co_client_start, data);
1448     qemu_coroutine_enter(data->co);
1449 }