1 /* 2 * Copyright (C) 2016-2018 Red Hat, Inc. 3 * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> 4 * 5 * Network Block Device Client 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 "trace.h" 23 #include "nbd-internal.h" 24 #include "qemu/cutils.h" 25 26 /* Definitions for opaque data types */ 27 28 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 29 30 /* That's all folks */ 31 32 /* Basic flow for negotiation 33 34 Server Client 35 Negotiate 36 37 or 38 39 Server Client 40 Negotiate #1 41 Option 42 Negotiate #2 43 44 ---- 45 46 followed by 47 48 Server Client 49 Request 50 Response 51 Request 52 Response 53 ... 54 ... 55 Request (type == 2) 56 57 */ 58 59 /* Send an option request. 60 * 61 * The request is for option @opt, with @data containing @len bytes of 62 * additional payload for the request (@len may be -1 to treat @data as 63 * a C string; and @data may be NULL if @len is 0). 64 * Return 0 if successful, -1 with errp set if it is impossible to 65 * continue. */ 66 static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt, 67 uint32_t len, const char *data, 68 Error **errp) 69 { 70 NBDOption req; 71 QEMU_BUILD_BUG_ON(sizeof(req) != 16); 72 73 if (len == -1) { 74 req.length = len = strlen(data); 75 } 76 trace_nbd_send_option_request(opt, nbd_opt_lookup(opt), len); 77 78 stq_be_p(&req.magic, NBD_OPTS_MAGIC); 79 stl_be_p(&req.option, opt); 80 stl_be_p(&req.length, len); 81 82 if (nbd_write(ioc, &req, sizeof(req), errp) < 0) { 83 error_prepend(errp, "Failed to send option request header: "); 84 return -1; 85 } 86 87 if (len && nbd_write(ioc, (char *) data, len, errp) < 0) { 88 error_prepend(errp, "Failed to send option request data: "); 89 return -1; 90 } 91 92 return 0; 93 } 94 95 /* Send NBD_OPT_ABORT as a courtesy to let the server know that we are 96 * not going to attempt further negotiation. */ 97 static void nbd_send_opt_abort(QIOChannel *ioc) 98 { 99 /* Technically, a compliant server is supposed to reply to us; but 100 * older servers disconnected instead. At any rate, we're allowed 101 * to disconnect without waiting for the server reply, so we don't 102 * even care if the request makes it to the server, let alone 103 * waiting around for whether the server replies. */ 104 nbd_send_option_request(ioc, NBD_OPT_ABORT, 0, NULL, NULL); 105 } 106 107 108 /* Receive the header of an option reply, which should match the given 109 * opt. Read through the length field, but NOT the length bytes of 110 * payload. Return 0 if successful, -1 with errp set if it is 111 * impossible to continue. */ 112 static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt, 113 NBDOptionReply *reply, Error **errp) 114 { 115 QEMU_BUILD_BUG_ON(sizeof(*reply) != 20); 116 if (nbd_read(ioc, reply, sizeof(*reply), "option reply", errp) < 0) { 117 nbd_send_opt_abort(ioc); 118 return -1; 119 } 120 reply->magic = be64_to_cpu(reply->magic); 121 reply->option = be32_to_cpu(reply->option); 122 reply->type = be32_to_cpu(reply->type); 123 reply->length = be32_to_cpu(reply->length); 124 125 trace_nbd_receive_option_reply(reply->option, nbd_opt_lookup(reply->option), 126 reply->type, nbd_rep_lookup(reply->type), 127 reply->length); 128 129 if (reply->magic != NBD_REP_MAGIC) { 130 error_setg(errp, "Unexpected option reply magic"); 131 nbd_send_opt_abort(ioc); 132 return -1; 133 } 134 if (reply->option != opt) { 135 error_setg(errp, "Unexpected option type %u (%s), expected %u (%s)", 136 reply->option, nbd_opt_lookup(reply->option), 137 opt, nbd_opt_lookup(opt)); 138 nbd_send_opt_abort(ioc); 139 return -1; 140 } 141 return 0; 142 } 143 144 /* If reply represents success, return 1 without further action. 145 * If reply represents an error, consume the optional payload of 146 * the packet on ioc. Then return 0 for unsupported (so the client 147 * can fall back to other approaches), or -1 with errp set for other 148 * errors. 149 */ 150 static int nbd_handle_reply_err(QIOChannel *ioc, NBDOptionReply *reply, 151 Error **errp) 152 { 153 char *msg = NULL; 154 int result = -1; 155 156 if (!(reply->type & (1 << 31))) { 157 return 1; 158 } 159 160 if (reply->length) { 161 if (reply->length > NBD_MAX_BUFFER_SIZE) { 162 error_setg(errp, "server error %" PRIu32 163 " (%s) message is too long", 164 reply->type, nbd_rep_lookup(reply->type)); 165 goto cleanup; 166 } 167 msg = g_malloc(reply->length + 1); 168 if (nbd_read(ioc, msg, reply->length, NULL, errp) < 0) { 169 error_prepend(errp, "Failed to read option error %" PRIu32 170 " (%s) message: ", 171 reply->type, nbd_rep_lookup(reply->type)); 172 goto cleanup; 173 } 174 msg[reply->length] = '\0'; 175 trace_nbd_server_error_msg(reply->type, 176 nbd_reply_type_lookup(reply->type), msg); 177 } 178 179 switch (reply->type) { 180 case NBD_REP_ERR_UNSUP: 181 trace_nbd_reply_err_unsup(reply->option, nbd_opt_lookup(reply->option)); 182 result = 0; 183 goto cleanup; 184 185 case NBD_REP_ERR_POLICY: 186 error_setg(errp, "Denied by server for option %" PRIu32 " (%s)", 187 reply->option, nbd_opt_lookup(reply->option)); 188 break; 189 190 case NBD_REP_ERR_INVALID: 191 error_setg(errp, "Invalid parameters for option %" PRIu32 " (%s)", 192 reply->option, nbd_opt_lookup(reply->option)); 193 break; 194 195 case NBD_REP_ERR_PLATFORM: 196 error_setg(errp, "Server lacks support for option %" PRIu32 " (%s)", 197 reply->option, nbd_opt_lookup(reply->option)); 198 break; 199 200 case NBD_REP_ERR_TLS_REQD: 201 error_setg(errp, "TLS negotiation required before option %" PRIu32 202 " (%s)", reply->option, nbd_opt_lookup(reply->option)); 203 break; 204 205 case NBD_REP_ERR_UNKNOWN: 206 error_setg(errp, "Requested export not available"); 207 break; 208 209 case NBD_REP_ERR_SHUTDOWN: 210 error_setg(errp, "Server shutting down before option %" PRIu32 " (%s)", 211 reply->option, nbd_opt_lookup(reply->option)); 212 break; 213 214 case NBD_REP_ERR_BLOCK_SIZE_REQD: 215 error_setg(errp, "Server requires INFO_BLOCK_SIZE for option %" PRIu32 216 " (%s)", reply->option, nbd_opt_lookup(reply->option)); 217 break; 218 219 default: 220 error_setg(errp, "Unknown error code when asking for option %" PRIu32 221 " (%s)", reply->option, nbd_opt_lookup(reply->option)); 222 break; 223 } 224 225 if (msg) { 226 error_append_hint(errp, "server reported: %s\n", msg); 227 } 228 229 cleanup: 230 g_free(msg); 231 if (result < 0) { 232 nbd_send_opt_abort(ioc); 233 } 234 return result; 235 } 236 237 /* nbd_receive_list: 238 * Process another portion of the NBD_OPT_LIST reply, populating any 239 * name received into *@name. If @description is non-NULL, and the 240 * server provided a description, that is also populated. The caller 241 * must eventually call g_free() on success. 242 * Returns 1 if name and description were set and iteration must continue, 243 * 0 if iteration is complete (including if OPT_LIST unsupported), 244 * -1 with @errp set if an unrecoverable error occurred. 245 */ 246 static int nbd_receive_list(QIOChannel *ioc, char **name, char **description, 247 Error **errp) 248 { 249 int ret = -1; 250 NBDOptionReply reply; 251 uint32_t len; 252 uint32_t namelen; 253 char *local_name = NULL; 254 char *local_desc = NULL; 255 int error; 256 257 if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) { 258 return -1; 259 } 260 error = nbd_handle_reply_err(ioc, &reply, errp); 261 if (error <= 0) { 262 return error; 263 } 264 len = reply.length; 265 266 if (reply.type == NBD_REP_ACK) { 267 if (len != 0) { 268 error_setg(errp, "length too long for option end"); 269 nbd_send_opt_abort(ioc); 270 return -1; 271 } 272 return 0; 273 } else if (reply.type != NBD_REP_SERVER) { 274 error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)", 275 reply.type, nbd_rep_lookup(reply.type), 276 NBD_REP_SERVER, nbd_rep_lookup(NBD_REP_SERVER)); 277 nbd_send_opt_abort(ioc); 278 return -1; 279 } 280 281 if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) { 282 error_setg(errp, "incorrect option length %" PRIu32, len); 283 nbd_send_opt_abort(ioc); 284 return -1; 285 } 286 if (nbd_read32(ioc, &namelen, "option name length", errp) < 0) { 287 nbd_send_opt_abort(ioc); 288 return -1; 289 } 290 len -= sizeof(namelen); 291 if (len < namelen) { 292 error_setg(errp, "incorrect option name length"); 293 nbd_send_opt_abort(ioc); 294 return -1; 295 } 296 297 local_name = g_malloc(namelen + 1); 298 if (nbd_read(ioc, local_name, namelen, "export name", errp) < 0) { 299 nbd_send_opt_abort(ioc); 300 goto out; 301 } 302 local_name[namelen] = '\0'; 303 len -= namelen; 304 if (len) { 305 local_desc = g_malloc(len + 1); 306 if (nbd_read(ioc, local_desc, len, "export description", errp) < 0) { 307 nbd_send_opt_abort(ioc); 308 goto out; 309 } 310 local_desc[len] = '\0'; 311 } 312 313 trace_nbd_receive_list(local_name, local_desc ?: ""); 314 *name = local_name; 315 local_name = NULL; 316 if (description) { 317 *description = local_desc; 318 local_desc = NULL; 319 } 320 ret = 1; 321 322 out: 323 g_free(local_name); 324 g_free(local_desc); 325 return ret; 326 } 327 328 329 /* 330 * nbd_opt_info_or_go: 331 * Send option for NBD_OPT_INFO or NBD_OPT_GO and parse the reply. 332 * Returns -1 if the option proves the export @info->name cannot be 333 * used, 0 if the option is unsupported (fall back to NBD_OPT_LIST and 334 * NBD_OPT_EXPORT_NAME in that case), and > 0 if the export is good to 335 * go (with the rest of @info populated). 336 */ 337 static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt, 338 NBDExportInfo *info, Error **errp) 339 { 340 NBDOptionReply reply; 341 uint32_t len = strlen(info->name); 342 uint16_t type; 343 int error; 344 char *buf; 345 346 /* The protocol requires that the server send NBD_INFO_EXPORT with 347 * a non-zero flags (at least NBD_FLAG_HAS_FLAGS must be set); so 348 * flags still 0 is a witness of a broken server. */ 349 info->flags = 0; 350 351 assert(opt == NBD_OPT_GO || opt == NBD_OPT_INFO); 352 trace_nbd_opt_info_go_start(nbd_opt_lookup(opt), info->name); 353 buf = g_malloc(4 + len + 2 + 2 * info->request_sizes + 1); 354 stl_be_p(buf, len); 355 memcpy(buf + 4, info->name, len); 356 /* At most one request, everything else up to server */ 357 stw_be_p(buf + 4 + len, info->request_sizes); 358 if (info->request_sizes) { 359 stw_be_p(buf + 4 + len + 2, NBD_INFO_BLOCK_SIZE); 360 } 361 error = nbd_send_option_request(ioc, opt, 362 4 + len + 2 + 2 * info->request_sizes, 363 buf, errp); 364 g_free(buf); 365 if (error < 0) { 366 return -1; 367 } 368 369 while (1) { 370 if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) { 371 return -1; 372 } 373 error = nbd_handle_reply_err(ioc, &reply, errp); 374 if (error <= 0) { 375 return error; 376 } 377 len = reply.length; 378 379 if (reply.type == NBD_REP_ACK) { 380 /* 381 * Server is done sending info, and moved into transmission 382 * phase for NBD_OPT_GO, but make sure it sent flags 383 */ 384 if (len) { 385 error_setg(errp, "server sent invalid NBD_REP_ACK"); 386 return -1; 387 } 388 if (!info->flags) { 389 error_setg(errp, "broken server omitted NBD_INFO_EXPORT"); 390 return -1; 391 } 392 trace_nbd_opt_info_go_success(nbd_opt_lookup(opt)); 393 return 1; 394 } 395 if (reply.type != NBD_REP_INFO) { 396 error_setg(errp, "unexpected reply type %u (%s), expected %u (%s)", 397 reply.type, nbd_rep_lookup(reply.type), 398 NBD_REP_INFO, nbd_rep_lookup(NBD_REP_INFO)); 399 nbd_send_opt_abort(ioc); 400 return -1; 401 } 402 if (len < sizeof(type)) { 403 error_setg(errp, "NBD_REP_INFO length %" PRIu32 " is too short", 404 len); 405 nbd_send_opt_abort(ioc); 406 return -1; 407 } 408 if (nbd_read16(ioc, &type, "info type", errp) < 0) { 409 nbd_send_opt_abort(ioc); 410 return -1; 411 } 412 len -= sizeof(type); 413 switch (type) { 414 case NBD_INFO_EXPORT: 415 if (len != sizeof(info->size) + sizeof(info->flags)) { 416 error_setg(errp, "remaining export info len %" PRIu32 417 " is unexpected size", len); 418 nbd_send_opt_abort(ioc); 419 return -1; 420 } 421 if (nbd_read64(ioc, &info->size, "info size", errp) < 0) { 422 nbd_send_opt_abort(ioc); 423 return -1; 424 } 425 if (nbd_read16(ioc, &info->flags, "info flags", errp) < 0) { 426 nbd_send_opt_abort(ioc); 427 return -1; 428 } 429 trace_nbd_receive_negotiate_size_flags(info->size, info->flags); 430 break; 431 432 case NBD_INFO_BLOCK_SIZE: 433 if (len != sizeof(info->min_block) * 3) { 434 error_setg(errp, "remaining export info len %" PRIu32 435 " is unexpected size", len); 436 nbd_send_opt_abort(ioc); 437 return -1; 438 } 439 if (nbd_read32(ioc, &info->min_block, "info minimum block size", 440 errp) < 0) { 441 nbd_send_opt_abort(ioc); 442 return -1; 443 } 444 if (!is_power_of_2(info->min_block)) { 445 error_setg(errp, "server minimum block size %" PRIu32 446 " is not a power of two", info->min_block); 447 nbd_send_opt_abort(ioc); 448 return -1; 449 } 450 if (nbd_read32(ioc, &info->opt_block, "info preferred block size", 451 errp) < 0) 452 { 453 nbd_send_opt_abort(ioc); 454 return -1; 455 } 456 if (!is_power_of_2(info->opt_block) || 457 info->opt_block < info->min_block) { 458 error_setg(errp, "server preferred block size %" PRIu32 459 " is not valid", info->opt_block); 460 nbd_send_opt_abort(ioc); 461 return -1; 462 } 463 if (nbd_read32(ioc, &info->max_block, "info maximum block size", 464 errp) < 0) 465 { 466 nbd_send_opt_abort(ioc); 467 return -1; 468 } 469 if (info->max_block < info->min_block) { 470 error_setg(errp, "server maximum block size %" PRIu32 471 " is not valid", info->max_block); 472 nbd_send_opt_abort(ioc); 473 return -1; 474 } 475 trace_nbd_opt_info_block_size(info->min_block, info->opt_block, 476 info->max_block); 477 break; 478 479 default: 480 trace_nbd_opt_info_unknown(type, nbd_info_lookup(type)); 481 if (nbd_drop(ioc, len, errp) < 0) { 482 error_prepend(errp, "Failed to read info payload: "); 483 nbd_send_opt_abort(ioc); 484 return -1; 485 } 486 break; 487 } 488 } 489 } 490 491 /* Return -1 on failure, 0 if wantname is an available export. */ 492 static int nbd_receive_query_exports(QIOChannel *ioc, 493 const char *wantname, 494 Error **errp) 495 { 496 bool list_empty = true; 497 bool found_export = false; 498 499 trace_nbd_receive_query_exports_start(wantname); 500 if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) { 501 return -1; 502 } 503 504 while (1) { 505 char *name; 506 int ret = nbd_receive_list(ioc, &name, NULL, errp); 507 508 if (ret < 0) { 509 /* Server gave unexpected reply */ 510 return -1; 511 } else if (ret == 0) { 512 /* Done iterating. */ 513 if (list_empty) { 514 /* 515 * We don't have enough context to tell a server that 516 * sent an empty list apart from a server that does 517 * not support the list command; but as this function 518 * is just used to trigger a nicer error message 519 * before trying NBD_OPT_EXPORT_NAME, assume the 520 * export is available. 521 */ 522 return 0; 523 } else if (!found_export) { 524 error_setg(errp, "No export with name '%s' available", 525 wantname); 526 nbd_send_opt_abort(ioc); 527 return -1; 528 } 529 trace_nbd_receive_query_exports_success(wantname); 530 return 0; 531 } 532 list_empty = false; 533 if (!strcmp(name, wantname)) { 534 found_export = true; 535 } 536 g_free(name); 537 } 538 } 539 540 /* nbd_request_simple_option: Send an option request, and parse the reply 541 * return 1 for successful negotiation, 542 * 0 if operation is unsupported, 543 * -1 with errp set for any other error 544 */ 545 static int nbd_request_simple_option(QIOChannel *ioc, int opt, Error **errp) 546 { 547 NBDOptionReply reply; 548 int error; 549 550 if (nbd_send_option_request(ioc, opt, 0, NULL, errp) < 0) { 551 return -1; 552 } 553 554 if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) { 555 return -1; 556 } 557 error = nbd_handle_reply_err(ioc, &reply, errp); 558 if (error <= 0) { 559 return error; 560 } 561 562 if (reply.type != NBD_REP_ACK) { 563 error_setg(errp, "Server answered option %d (%s) with unexpected " 564 "reply %" PRIu32 " (%s)", opt, nbd_opt_lookup(opt), 565 reply.type, nbd_rep_lookup(reply.type)); 566 nbd_send_opt_abort(ioc); 567 return -1; 568 } 569 570 if (reply.length != 0) { 571 error_setg(errp, "Option %d ('%s') response length is %" PRIu32 572 " (it should be zero)", opt, nbd_opt_lookup(opt), 573 reply.length); 574 nbd_send_opt_abort(ioc); 575 return -1; 576 } 577 578 return 1; 579 } 580 581 static QIOChannel *nbd_receive_starttls(QIOChannel *ioc, 582 QCryptoTLSCreds *tlscreds, 583 const char *hostname, Error **errp) 584 { 585 int ret; 586 QIOChannelTLS *tioc; 587 struct NBDTLSHandshakeData data = { 0 }; 588 589 ret = nbd_request_simple_option(ioc, NBD_OPT_STARTTLS, errp); 590 if (ret <= 0) { 591 if (ret == 0) { 592 error_setg(errp, "Server don't support STARTTLS option"); 593 nbd_send_opt_abort(ioc); 594 } 595 return NULL; 596 } 597 598 trace_nbd_receive_starttls_new_client(); 599 tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp); 600 if (!tioc) { 601 return NULL; 602 } 603 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-client-tls"); 604 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 605 trace_nbd_receive_starttls_tls_handshake(); 606 qio_channel_tls_handshake(tioc, 607 nbd_tls_handshake, 608 &data, 609 NULL, 610 NULL); 611 612 if (!data.complete) { 613 g_main_loop_run(data.loop); 614 } 615 g_main_loop_unref(data.loop); 616 if (data.error) { 617 error_propagate(errp, data.error); 618 object_unref(OBJECT(tioc)); 619 return NULL; 620 } 621 622 return QIO_CHANNEL(tioc); 623 } 624 625 /* 626 * nbd_send_meta_query: 627 * Send 0 or 1 set/list meta context queries. 628 * Return 0 on success, -1 with errp set for any error 629 */ 630 static int nbd_send_meta_query(QIOChannel *ioc, uint32_t opt, 631 const char *export, const char *query, 632 Error **errp) 633 { 634 int ret; 635 uint32_t export_len = strlen(export); 636 uint32_t queries = !!query; 637 uint32_t query_len = 0; 638 uint32_t data_len; 639 char *data; 640 char *p; 641 642 data_len = sizeof(export_len) + export_len + sizeof(queries); 643 if (query) { 644 query_len = strlen(query); 645 data_len += sizeof(query_len) + query_len; 646 } else { 647 assert(opt == NBD_OPT_LIST_META_CONTEXT); 648 } 649 p = data = g_malloc(data_len); 650 651 trace_nbd_opt_meta_request(nbd_opt_lookup(opt), query ?: "(all)", export); 652 stl_be_p(p, export_len); 653 memcpy(p += sizeof(export_len), export, export_len); 654 stl_be_p(p += export_len, queries); 655 if (query) { 656 stl_be_p(p += sizeof(queries), query_len); 657 memcpy(p += sizeof(query_len), query, query_len); 658 } 659 660 ret = nbd_send_option_request(ioc, opt, data_len, data, errp); 661 g_free(data); 662 return ret; 663 } 664 665 /* 666 * nbd_receive_one_meta_context: 667 * Called in a loop to receive and trace one set/list meta context reply. 668 * Pass non-NULL @name or @id to collect results back to the caller, which 669 * must eventually call g_free(). 670 * return 1 if name is set and iteration must continue, 671 * 0 if iteration is complete (including if option is unsupported), 672 * -1 with errp set for any error 673 */ 674 static int nbd_receive_one_meta_context(QIOChannel *ioc, 675 uint32_t opt, 676 char **name, 677 uint32_t *id, 678 Error **errp) 679 { 680 int ret; 681 NBDOptionReply reply; 682 char *local_name = NULL; 683 uint32_t local_id; 684 685 if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) { 686 return -1; 687 } 688 689 ret = nbd_handle_reply_err(ioc, &reply, errp); 690 if (ret <= 0) { 691 return ret; 692 } 693 694 if (reply.type == NBD_REP_ACK) { 695 if (reply.length != 0) { 696 error_setg(errp, "Unexpected length to ACK response"); 697 nbd_send_opt_abort(ioc); 698 return -1; 699 } 700 return 0; 701 } else if (reply.type != NBD_REP_META_CONTEXT) { 702 error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)", 703 reply.type, nbd_rep_lookup(reply.type), 704 NBD_REP_META_CONTEXT, nbd_rep_lookup(NBD_REP_META_CONTEXT)); 705 nbd_send_opt_abort(ioc); 706 return -1; 707 } 708 709 if (reply.length <= sizeof(local_id) || 710 reply.length > NBD_MAX_BUFFER_SIZE) { 711 error_setg(errp, "Failed to negotiate meta context, server " 712 "answered with unexpected length %" PRIu32, 713 reply.length); 714 nbd_send_opt_abort(ioc); 715 return -1; 716 } 717 718 if (nbd_read32(ioc, &local_id, "context id", errp) < 0) { 719 return -1; 720 } 721 722 reply.length -= sizeof(local_id); 723 local_name = g_malloc(reply.length + 1); 724 if (nbd_read(ioc, local_name, reply.length, "context name", errp) < 0) { 725 g_free(local_name); 726 return -1; 727 } 728 local_name[reply.length] = '\0'; 729 trace_nbd_opt_meta_reply(nbd_opt_lookup(opt), local_name, local_id); 730 731 if (name) { 732 *name = local_name; 733 } else { 734 g_free(local_name); 735 } 736 if (id) { 737 *id = local_id; 738 } 739 return 1; 740 } 741 742 /* 743 * nbd_negotiate_simple_meta_context: 744 * Request the server to set the meta context for export @info->name 745 * using @info->x_dirty_bitmap with a fallback to "base:allocation", 746 * setting @info->context_id to the resulting id. Fail if the server 747 * responds with more than one context or with a context different 748 * than the query. 749 * return 1 for successful negotiation, 750 * 0 if operation is unsupported, 751 * -1 with errp set for any other error 752 */ 753 static int nbd_negotiate_simple_meta_context(QIOChannel *ioc, 754 NBDExportInfo *info, 755 Error **errp) 756 { 757 /* 758 * TODO: Removing the x_dirty_bitmap hack will mean refactoring 759 * this function to request and store ids for multiple contexts 760 * (both base:allocation and a dirty bitmap), at which point this 761 * function should lose the term _simple. 762 */ 763 int ret; 764 const char *context = info->x_dirty_bitmap ?: "base:allocation"; 765 bool received = false; 766 char *name = NULL; 767 768 if (nbd_send_meta_query(ioc, NBD_OPT_SET_META_CONTEXT, 769 info->name, context, errp) < 0) { 770 return -1; 771 } 772 773 ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT, 774 &name, &info->context_id, errp); 775 if (ret < 0) { 776 return -1; 777 } 778 if (ret == 1) { 779 if (strcmp(context, name)) { 780 error_setg(errp, "Failed to negotiate meta context '%s', server " 781 "answered with different context '%s'", context, 782 name); 783 g_free(name); 784 nbd_send_opt_abort(ioc); 785 return -1; 786 } 787 g_free(name); 788 received = true; 789 790 ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT, 791 NULL, NULL, errp); 792 if (ret < 0) { 793 return -1; 794 } 795 } 796 if (ret != 0) { 797 error_setg(errp, "Server answered with more than one context"); 798 nbd_send_opt_abort(ioc); 799 return -1; 800 } 801 return received; 802 } 803 804 /* 805 * nbd_list_meta_contexts: 806 * Request the server to list all meta contexts for export @info->name. 807 * return 0 if list is complete (even if empty), 808 * -1 with errp set for any error 809 */ 810 static int nbd_list_meta_contexts(QIOChannel *ioc, 811 NBDExportInfo *info, 812 Error **errp) 813 { 814 int ret; 815 int seen_any = false; 816 int seen_qemu = false; 817 818 if (nbd_send_meta_query(ioc, NBD_OPT_LIST_META_CONTEXT, 819 info->name, NULL, errp) < 0) { 820 return -1; 821 } 822 823 while (1) { 824 char *context; 825 826 ret = nbd_receive_one_meta_context(ioc, NBD_OPT_LIST_META_CONTEXT, 827 &context, NULL, errp); 828 if (ret == 0 && seen_any && !seen_qemu) { 829 /* 830 * Work around qemu 3.0 bug: the server forgot to send 831 * "qemu:" replies to 0 queries. If we saw at least one 832 * reply (probably base:allocation), but none of them were 833 * qemu:, then run a more specific query to make sure. 834 */ 835 seen_qemu = true; 836 if (nbd_send_meta_query(ioc, NBD_OPT_LIST_META_CONTEXT, 837 info->name, "qemu:", errp) < 0) { 838 return -1; 839 } 840 continue; 841 } 842 if (ret <= 0) { 843 return ret; 844 } 845 seen_any = true; 846 seen_qemu |= strstart(context, "qemu:", NULL); 847 info->contexts = g_renew(char *, info->contexts, ++info->n_contexts); 848 info->contexts[info->n_contexts - 1] = context; 849 } 850 } 851 852 /* 853 * nbd_start_negotiate: 854 * Start the handshake to the server. After a positive return, the server 855 * is ready to accept additional NBD_OPT requests. 856 * Returns: negative errno: failure talking to server 857 * 0: server is oldstyle, must call nbd_negotiate_finish_oldstyle 858 * 1: server is newstyle, but can only accept EXPORT_NAME 859 * 2: server is newstyle, but lacks structured replies 860 * 3: server is newstyle and set up for structured replies 861 */ 862 static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 863 const char *hostname, QIOChannel **outioc, 864 bool structured_reply, bool *zeroes, 865 Error **errp) 866 { 867 uint64_t magic; 868 869 trace_nbd_start_negotiate(tlscreds, hostname ? hostname : "<null>"); 870 871 if (zeroes) { 872 *zeroes = true; 873 } 874 if (outioc) { 875 *outioc = NULL; 876 } 877 if (tlscreds && !outioc) { 878 error_setg(errp, "Output I/O channel required for TLS"); 879 return -EINVAL; 880 } 881 882 if (nbd_read64(ioc, &magic, "initial magic", errp) < 0) { 883 return -EINVAL; 884 } 885 trace_nbd_receive_negotiate_magic(magic); 886 887 if (magic != NBD_INIT_MAGIC) { 888 error_setg(errp, "Bad initial magic received: 0x%" PRIx64, magic); 889 return -EINVAL; 890 } 891 892 if (nbd_read64(ioc, &magic, "server magic", errp) < 0) { 893 return -EINVAL; 894 } 895 trace_nbd_receive_negotiate_magic(magic); 896 897 if (magic == NBD_OPTS_MAGIC) { 898 uint32_t clientflags = 0; 899 uint16_t globalflags; 900 bool fixedNewStyle = false; 901 902 if (nbd_read16(ioc, &globalflags, "server flags", errp) < 0) { 903 return -EINVAL; 904 } 905 trace_nbd_receive_negotiate_server_flags(globalflags); 906 if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) { 907 fixedNewStyle = true; 908 clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE; 909 } 910 if (globalflags & NBD_FLAG_NO_ZEROES) { 911 if (zeroes) { 912 *zeroes = false; 913 } 914 clientflags |= NBD_FLAG_C_NO_ZEROES; 915 } 916 /* client requested flags */ 917 clientflags = cpu_to_be32(clientflags); 918 if (nbd_write(ioc, &clientflags, sizeof(clientflags), errp) < 0) { 919 error_prepend(errp, "Failed to send clientflags field: "); 920 return -EINVAL; 921 } 922 if (tlscreds) { 923 if (fixedNewStyle) { 924 *outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp); 925 if (!*outioc) { 926 return -EINVAL; 927 } 928 ioc = *outioc; 929 } else { 930 error_setg(errp, "Server does not support STARTTLS"); 931 return -EINVAL; 932 } 933 } 934 if (fixedNewStyle) { 935 int result = 0; 936 937 if (structured_reply) { 938 result = nbd_request_simple_option(ioc, 939 NBD_OPT_STRUCTURED_REPLY, 940 errp); 941 if (result < 0) { 942 return -EINVAL; 943 } 944 } 945 return 2 + result; 946 } else { 947 return 1; 948 } 949 } else if (magic == NBD_CLIENT_MAGIC) { 950 if (tlscreds) { 951 error_setg(errp, "Server does not support STARTTLS"); 952 return -EINVAL; 953 } 954 return 0; 955 } else { 956 error_setg(errp, "Bad server magic received: 0x%" PRIx64, magic); 957 return -EINVAL; 958 } 959 } 960 961 /* 962 * nbd_negotiate_finish_oldstyle: 963 * Populate @info with the size and export flags from an oldstyle server, 964 * but does not consume 124 bytes of reserved zero padding. 965 * Returns 0 on success, -1 with @errp set on failure 966 */ 967 static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info, 968 Error **errp) 969 { 970 uint32_t oldflags; 971 972 if (nbd_read64(ioc, &info->size, "export length", errp) < 0) { 973 return -EINVAL; 974 } 975 976 if (nbd_read32(ioc, &oldflags, "export flags", errp) < 0) { 977 return -EINVAL; 978 } 979 if (oldflags & ~0xffff) { 980 error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags); 981 return -EINVAL; 982 } 983 info->flags = oldflags; 984 return 0; 985 } 986 987 /* 988 * nbd_receive_negotiate: 989 * Connect to server, complete negotiation, and move into transmission phase. 990 * Returns: negative errno: failure talking to server 991 * 0: server is connected 992 */ 993 int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 994 const char *hostname, QIOChannel **outioc, 995 NBDExportInfo *info, Error **errp) 996 { 997 int result; 998 bool zeroes; 999 bool base_allocation = info->base_allocation; 1000 1001 assert(info->name); 1002 trace_nbd_receive_negotiate_name(info->name); 1003 1004 result = nbd_start_negotiate(ioc, tlscreds, hostname, outioc, 1005 info->structured_reply, &zeroes, errp); 1006 1007 info->structured_reply = false; 1008 info->base_allocation = false; 1009 if (tlscreds && *outioc) { 1010 ioc = *outioc; 1011 } 1012 1013 switch (result) { 1014 case 3: /* newstyle, with structured replies */ 1015 info->structured_reply = true; 1016 if (base_allocation) { 1017 result = nbd_negotiate_simple_meta_context(ioc, info, errp); 1018 if (result < 0) { 1019 return -EINVAL; 1020 } 1021 info->base_allocation = result == 1; 1022 } 1023 /* fall through */ 1024 case 2: /* newstyle, try OPT_GO */ 1025 /* Try NBD_OPT_GO first - if it works, we are done (it 1026 * also gives us a good message if the server requires 1027 * TLS). If it is not available, fall back to 1028 * NBD_OPT_LIST for nicer error messages about a missing 1029 * export, then use NBD_OPT_EXPORT_NAME. */ 1030 result = nbd_opt_info_or_go(ioc, NBD_OPT_GO, info, errp); 1031 if (result < 0) { 1032 return -EINVAL; 1033 } 1034 if (result > 0) { 1035 return 0; 1036 } 1037 /* Check our desired export is present in the 1038 * server export list. Since NBD_OPT_EXPORT_NAME 1039 * cannot return an error message, running this 1040 * query gives us better error reporting if the 1041 * export name is not available. 1042 */ 1043 if (nbd_receive_query_exports(ioc, info->name, errp) < 0) { 1044 return -EINVAL; 1045 } 1046 /* fall through */ 1047 case 1: /* newstyle, but limited to EXPORT_NAME */ 1048 /* write the export name request */ 1049 if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, info->name, 1050 errp) < 0) { 1051 return -EINVAL; 1052 } 1053 1054 /* Read the response */ 1055 if (nbd_read64(ioc, &info->size, "export length", errp) < 0) { 1056 return -EINVAL; 1057 } 1058 1059 if (nbd_read16(ioc, &info->flags, "export flags", errp) < 0) { 1060 return -EINVAL; 1061 } 1062 break; 1063 case 0: /* oldstyle, parse length and flags */ 1064 if (*info->name) { 1065 error_setg(errp, "Server does not support non-empty export names"); 1066 return -EINVAL; 1067 } 1068 if (nbd_negotiate_finish_oldstyle(ioc, info, errp) < 0) { 1069 return -EINVAL; 1070 } 1071 break; 1072 default: 1073 return result; 1074 } 1075 1076 trace_nbd_receive_negotiate_size_flags(info->size, info->flags); 1077 if (zeroes && nbd_drop(ioc, 124, errp) < 0) { 1078 error_prepend(errp, "Failed to read reserved block: "); 1079 return -EINVAL; 1080 } 1081 return 0; 1082 } 1083 1084 /* Clean up result of nbd_receive_export_list */ 1085 void nbd_free_export_list(NBDExportInfo *info, int count) 1086 { 1087 int i, j; 1088 1089 if (!info) { 1090 return; 1091 } 1092 1093 for (i = 0; i < count; i++) { 1094 g_free(info[i].name); 1095 g_free(info[i].description); 1096 for (j = 0; j < info[i].n_contexts; j++) { 1097 g_free(info[i].contexts[j]); 1098 } 1099 g_free(info[i].contexts); 1100 } 1101 g_free(info); 1102 } 1103 1104 /* 1105 * nbd_receive_export_list: 1106 * Query details about a server's exports, then disconnect without 1107 * going into transmission phase. Return a count of the exports listed 1108 * in @info by the server, or -1 on error. Caller must free @info using 1109 * nbd_free_export_list(). 1110 */ 1111 int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 1112 const char *hostname, NBDExportInfo **info, 1113 Error **errp) 1114 { 1115 int result; 1116 int count = 0; 1117 int i; 1118 int rc; 1119 int ret = -1; 1120 NBDExportInfo *array = NULL; 1121 QIOChannel *sioc = NULL; 1122 1123 *info = NULL; 1124 result = nbd_start_negotiate(ioc, tlscreds, hostname, &sioc, true, NULL, 1125 errp); 1126 if (tlscreds && sioc) { 1127 ioc = sioc; 1128 } 1129 1130 switch (result) { 1131 case 2: 1132 case 3: 1133 /* newstyle - use NBD_OPT_LIST to populate array, then try 1134 * NBD_OPT_INFO on each array member. If structured replies 1135 * are enabled, also try NBD_OPT_LIST_META_CONTEXT. */ 1136 if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) { 1137 goto out; 1138 } 1139 while (1) { 1140 char *name; 1141 char *desc; 1142 1143 rc = nbd_receive_list(ioc, &name, &desc, errp); 1144 if (rc < 0) { 1145 goto out; 1146 } else if (rc == 0) { 1147 break; 1148 } 1149 array = g_renew(NBDExportInfo, array, ++count); 1150 memset(&array[count - 1], 0, sizeof(*array)); 1151 array[count - 1].name = name; 1152 array[count - 1].description = desc; 1153 array[count - 1].structured_reply = result == 3; 1154 } 1155 1156 for (i = 0; i < count; i++) { 1157 array[i].request_sizes = true; 1158 rc = nbd_opt_info_or_go(ioc, NBD_OPT_INFO, &array[i], errp); 1159 if (rc < 0) { 1160 goto out; 1161 } else if (rc == 0) { 1162 /* 1163 * Pointless to try rest of loop. If OPT_INFO doesn't work, 1164 * it's unlikely that meta contexts work either 1165 */ 1166 break; 1167 } 1168 1169 if (result == 3 && 1170 nbd_list_meta_contexts(ioc, &array[i], errp) < 0) { 1171 goto out; 1172 } 1173 } 1174 1175 /* Send NBD_OPT_ABORT as a courtesy before hanging up */ 1176 nbd_send_opt_abort(ioc); 1177 break; 1178 case 1: /* newstyle, but limited to EXPORT_NAME */ 1179 error_setg(errp, "Server does not support export lists"); 1180 /* We can't even send NBD_OPT_ABORT, so merely hang up */ 1181 goto out; 1182 case 0: /* oldstyle, parse length and flags */ 1183 array = g_new0(NBDExportInfo, 1); 1184 array->name = g_strdup(""); 1185 count = 1; 1186 1187 if (nbd_negotiate_finish_oldstyle(ioc, array, errp) < 0) { 1188 goto out; 1189 } 1190 1191 /* Send NBD_CMD_DISC as a courtesy to the server, but ignore all 1192 * errors now that we have the information we wanted. */ 1193 if (nbd_drop(ioc, 124, NULL) == 0) { 1194 NBDRequest request = { .type = NBD_CMD_DISC }; 1195 1196 nbd_send_request(ioc, &request); 1197 } 1198 break; 1199 default: 1200 goto out; 1201 } 1202 1203 *info = array; 1204 array = NULL; 1205 ret = count; 1206 1207 out: 1208 qio_channel_shutdown(ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); 1209 qio_channel_close(ioc, NULL); 1210 object_unref(OBJECT(sioc)); 1211 nbd_free_export_list(array, count); 1212 return ret; 1213 } 1214 1215 #ifdef __linux__ 1216 int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info, 1217 Error **errp) 1218 { 1219 unsigned long sector_size = MAX(BDRV_SECTOR_SIZE, info->min_block); 1220 unsigned long sectors = info->size / sector_size; 1221 1222 /* FIXME: Once the kernel module is patched to honor block sizes, 1223 * and to advertise that fact to user space, we should update the 1224 * hand-off to the kernel to use any block sizes we learned. */ 1225 assert(!info->request_sizes); 1226 if (info->size / sector_size != sectors) { 1227 error_setg(errp, "Export size %" PRIu64 " too large for 32-bit kernel", 1228 info->size); 1229 return -E2BIG; 1230 } 1231 1232 trace_nbd_init_set_socket(); 1233 1234 if (ioctl(fd, NBD_SET_SOCK, (unsigned long) sioc->fd) < 0) { 1235 int serrno = errno; 1236 error_setg(errp, "Failed to set NBD socket"); 1237 return -serrno; 1238 } 1239 1240 trace_nbd_init_set_block_size(sector_size); 1241 1242 if (ioctl(fd, NBD_SET_BLKSIZE, sector_size) < 0) { 1243 int serrno = errno; 1244 error_setg(errp, "Failed setting NBD block size"); 1245 return -serrno; 1246 } 1247 1248 trace_nbd_init_set_size(sectors); 1249 if (info->size % sector_size) { 1250 trace_nbd_init_trailing_bytes(info->size % sector_size); 1251 } 1252 1253 if (ioctl(fd, NBD_SET_SIZE_BLOCKS, sectors) < 0) { 1254 int serrno = errno; 1255 error_setg(errp, "Failed setting size (in blocks)"); 1256 return -serrno; 1257 } 1258 1259 if (ioctl(fd, NBD_SET_FLAGS, (unsigned long) info->flags) < 0) { 1260 if (errno == ENOTTY) { 1261 int read_only = (info->flags & NBD_FLAG_READ_ONLY) != 0; 1262 trace_nbd_init_set_readonly(); 1263 1264 if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) { 1265 int serrno = errno; 1266 error_setg(errp, "Failed setting read-only attribute"); 1267 return -serrno; 1268 } 1269 } else { 1270 int serrno = errno; 1271 error_setg(errp, "Failed setting flags"); 1272 return -serrno; 1273 } 1274 } 1275 1276 trace_nbd_init_finish(); 1277 1278 return 0; 1279 } 1280 1281 int nbd_client(int fd) 1282 { 1283 int ret; 1284 int serrno; 1285 1286 trace_nbd_client_loop(); 1287 1288 ret = ioctl(fd, NBD_DO_IT); 1289 if (ret < 0 && errno == EPIPE) { 1290 /* NBD_DO_IT normally returns EPIPE when someone has disconnected 1291 * the socket via NBD_DISCONNECT. We do not want to return 1 in 1292 * that case. 1293 */ 1294 ret = 0; 1295 } 1296 serrno = errno; 1297 1298 trace_nbd_client_loop_ret(ret, strerror(serrno)); 1299 1300 trace_nbd_client_clear_queue(); 1301 ioctl(fd, NBD_CLEAR_QUE); 1302 1303 trace_nbd_client_clear_socket(); 1304 ioctl(fd, NBD_CLEAR_SOCK); 1305 1306 errno = serrno; 1307 return ret; 1308 } 1309 1310 int nbd_disconnect(int fd) 1311 { 1312 ioctl(fd, NBD_CLEAR_QUE); 1313 ioctl(fd, NBD_DISCONNECT); 1314 ioctl(fd, NBD_CLEAR_SOCK); 1315 return 0; 1316 } 1317 1318 #endif /* __linux__ */ 1319 1320 int nbd_send_request(QIOChannel *ioc, NBDRequest *request) 1321 { 1322 uint8_t buf[NBD_REQUEST_SIZE]; 1323 1324 trace_nbd_send_request(request->from, request->len, request->handle, 1325 request->flags, request->type, 1326 nbd_cmd_lookup(request->type)); 1327 1328 stl_be_p(buf, NBD_REQUEST_MAGIC); 1329 stw_be_p(buf + 4, request->flags); 1330 stw_be_p(buf + 6, request->type); 1331 stq_be_p(buf + 8, request->handle); 1332 stq_be_p(buf + 16, request->from); 1333 stl_be_p(buf + 24, request->len); 1334 1335 return nbd_write(ioc, buf, sizeof(buf), NULL); 1336 } 1337 1338 /* nbd_receive_simple_reply 1339 * Read simple reply except magic field (which should be already read). 1340 * Payload is not read (payload is possible for CMD_READ, but here we even 1341 * don't know whether it take place or not). 1342 */ 1343 static int nbd_receive_simple_reply(QIOChannel *ioc, NBDSimpleReply *reply, 1344 Error **errp) 1345 { 1346 int ret; 1347 1348 assert(reply->magic == NBD_SIMPLE_REPLY_MAGIC); 1349 1350 ret = nbd_read(ioc, (uint8_t *)reply + sizeof(reply->magic), 1351 sizeof(*reply) - sizeof(reply->magic), "reply", errp); 1352 if (ret < 0) { 1353 return ret; 1354 } 1355 1356 reply->error = be32_to_cpu(reply->error); 1357 reply->handle = be64_to_cpu(reply->handle); 1358 1359 return 0; 1360 } 1361 1362 /* nbd_receive_structured_reply_chunk 1363 * Read structured reply chunk except magic field (which should be already 1364 * read). 1365 * Payload is not read. 1366 */ 1367 static int nbd_receive_structured_reply_chunk(QIOChannel *ioc, 1368 NBDStructuredReplyChunk *chunk, 1369 Error **errp) 1370 { 1371 int ret; 1372 1373 assert(chunk->magic == NBD_STRUCTURED_REPLY_MAGIC); 1374 1375 ret = nbd_read(ioc, (uint8_t *)chunk + sizeof(chunk->magic), 1376 sizeof(*chunk) - sizeof(chunk->magic), "structured chunk", 1377 errp); 1378 if (ret < 0) { 1379 return ret; 1380 } 1381 1382 chunk->flags = be16_to_cpu(chunk->flags); 1383 chunk->type = be16_to_cpu(chunk->type); 1384 chunk->handle = be64_to_cpu(chunk->handle); 1385 chunk->length = be32_to_cpu(chunk->length); 1386 1387 return 0; 1388 } 1389 1390 /* nbd_read_eof 1391 * Tries to read @size bytes from @ioc. 1392 * Returns 1 on success 1393 * 0 on eof, when no data was read (errp is not set) 1394 * negative errno on failure (errp is set) 1395 */ 1396 static inline int coroutine_fn 1397 nbd_read_eof(BlockDriverState *bs, QIOChannel *ioc, void *buffer, size_t size, 1398 Error **errp) 1399 { 1400 bool partial = false; 1401 1402 assert(size); 1403 while (size > 0) { 1404 struct iovec iov = { .iov_base = buffer, .iov_len = size }; 1405 ssize_t len; 1406 1407 len = qio_channel_readv(ioc, &iov, 1, errp); 1408 if (len == QIO_CHANNEL_ERR_BLOCK) { 1409 bdrv_dec_in_flight(bs); 1410 qio_channel_yield(ioc, G_IO_IN); 1411 bdrv_inc_in_flight(bs); 1412 continue; 1413 } else if (len < 0) { 1414 return -EIO; 1415 } else if (len == 0) { 1416 if (partial) { 1417 error_setg(errp, 1418 "Unexpected end-of-file before all bytes were read"); 1419 return -EIO; 1420 } else { 1421 return 0; 1422 } 1423 } 1424 1425 partial = true; 1426 size -= len; 1427 buffer = (uint8_t*) buffer + len; 1428 } 1429 return 1; 1430 } 1431 1432 /* nbd_receive_reply 1433 * 1434 * Decreases bs->in_flight while waiting for a new reply. This yield is where 1435 * we wait indefinitely and the coroutine must be able to be safely reentered 1436 * for nbd_client_attach_aio_context(). 1437 * 1438 * Returns 1 on success 1439 * 0 on eof, when no data was read (errp is not set) 1440 * negative errno on failure (errp is set) 1441 */ 1442 int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc, 1443 NBDReply *reply, Error **errp) 1444 { 1445 int ret; 1446 const char *type; 1447 1448 ret = nbd_read_eof(bs, ioc, &reply->magic, sizeof(reply->magic), errp); 1449 if (ret <= 0) { 1450 return ret; 1451 } 1452 1453 reply->magic = be32_to_cpu(reply->magic); 1454 1455 switch (reply->magic) { 1456 case NBD_SIMPLE_REPLY_MAGIC: 1457 ret = nbd_receive_simple_reply(ioc, &reply->simple, errp); 1458 if (ret < 0) { 1459 break; 1460 } 1461 trace_nbd_receive_simple_reply(reply->simple.error, 1462 nbd_err_lookup(reply->simple.error), 1463 reply->handle); 1464 break; 1465 case NBD_STRUCTURED_REPLY_MAGIC: 1466 ret = nbd_receive_structured_reply_chunk(ioc, &reply->structured, errp); 1467 if (ret < 0) { 1468 break; 1469 } 1470 type = nbd_reply_type_lookup(reply->structured.type); 1471 trace_nbd_receive_structured_reply_chunk(reply->structured.flags, 1472 reply->structured.type, type, 1473 reply->structured.handle, 1474 reply->structured.length); 1475 break; 1476 default: 1477 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", reply->magic); 1478 return -EINVAL; 1479 } 1480 if (ret < 0) { 1481 return ret; 1482 } 1483 1484 return 1; 1485 } 1486 1487