qapi: Purge error_propagate() from QAPI core
[qemu.git] / nbd / client.c
1 /*
2 * Copyright (C) 2016-2019 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 "qemu/queue.h"
23 #include "trace.h"
24 #include "nbd-internal.h"
25 #include "qemu/cutils.h"
26
27 /* Definitions for opaque data types */
28
29 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
30
31 /* That's all folks */
32
33 /* Basic flow for negotiation
34
35 Server Client
36 Negotiate
37
38 or
39
40 Server Client
41 Negotiate #1
42 Option
43 Negotiate #2
44
45 ----
46
47 followed by
48
49 Server Client
50 Request
51 Response
52 Request
53 Response
54 ...
55 ...
56 Request (type == 2)
57
58 */
59
60 /* Send an option request.
61 *
62 * The request is for option @opt, with @data containing @len bytes of
63 * additional payload for the request (@len may be -1 to treat @data as
64 * a C string; and @data may be NULL if @len is 0).
65 * Return 0 if successful, -1 with errp set if it is impossible to
66 * continue. */
67 static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt,
68 uint32_t len, const char *data,
69 Error **errp)
70 {
71 NBDOption req;
72 QEMU_BUILD_BUG_ON(sizeof(req) != 16);
73
74 if (len == -1) {
75 req.length = len = strlen(data);
76 }
77 trace_nbd_send_option_request(opt, nbd_opt_lookup(opt), len);
78
79 stq_be_p(&req.magic, NBD_OPTS_MAGIC);
80 stl_be_p(&req.option, opt);
81 stl_be_p(&req.length, len);
82
83 if (nbd_write(ioc, &req, sizeof(req), errp) < 0) {
84 error_prepend(errp, "Failed to send option request header: ");
85 return -1;
86 }
87
88 if (len && nbd_write(ioc, (char *) data, len, errp) < 0) {
89 error_prepend(errp, "Failed to send option request data: ");
90 return -1;
91 }
92
93 return 0;
94 }
95
96 /* Send NBD_OPT_ABORT as a courtesy to let the server know that we are
97 * not going to attempt further negotiation. */
98 static void nbd_send_opt_abort(QIOChannel *ioc)
99 {
100 /* Technically, a compliant server is supposed to reply to us; but
101 * older servers disconnected instead. At any rate, we're allowed
102 * to disconnect without waiting for the server reply, so we don't
103 * even care if the request makes it to the server, let alone
104 * waiting around for whether the server replies. */
105 nbd_send_option_request(ioc, NBD_OPT_ABORT, 0, NULL, NULL);
106 }
107
108
109 /* Receive the header of an option reply, which should match the given
110 * opt. Read through the length field, but NOT the length bytes of
111 * payload. Return 0 if successful, -1 with errp set if it is
112 * impossible to continue. */
113 static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt,
114 NBDOptionReply *reply, Error **errp)
115 {
116 QEMU_BUILD_BUG_ON(sizeof(*reply) != 20);
117 if (nbd_read(ioc, reply, sizeof(*reply), "option reply", errp) < 0) {
118 nbd_send_opt_abort(ioc);
119 return -1;
120 }
121 reply->magic = be64_to_cpu(reply->magic);
122 reply->option = be32_to_cpu(reply->option);
123 reply->type = be32_to_cpu(reply->type);
124 reply->length = be32_to_cpu(reply->length);
125
126 trace_nbd_receive_option_reply(reply->option, nbd_opt_lookup(reply->option),
127 reply->type, nbd_rep_lookup(reply->type),
128 reply->length);
129
130 if (reply->magic != NBD_REP_MAGIC) {
131 error_setg(errp, "Unexpected option reply magic");
132 nbd_send_opt_abort(ioc);
133 return -1;
134 }
135 if (reply->option != opt) {
136 error_setg(errp, "Unexpected option type %u (%s), expected %u (%s)",
137 reply->option, nbd_opt_lookup(reply->option),
138 opt, nbd_opt_lookup(opt));
139 nbd_send_opt_abort(ioc);
140 return -1;
141 }
142 return 0;
143 }
144
145 /*
146 * If reply represents success, return 1 without further action. If
147 * reply represents an error, consume the optional payload of the
148 * packet on ioc. Then return 0 for unsupported (so the client can
149 * fall back to other approaches), where @strict determines if only
150 * ERR_UNSUP or all errors fit that category, or -1 with errp set for
151 * other errors.
152 */
153 static int nbd_handle_reply_err(QIOChannel *ioc, NBDOptionReply *reply,
154 bool strict, Error **errp)
155 {
156 g_autofree char *msg = NULL;
157
158 if (!(reply->type & (1 << 31))) {
159 return 1;
160 }
161
162 if (reply->length) {
163 if (reply->length > NBD_MAX_BUFFER_SIZE) {
164 error_setg(errp, "server error %" PRIu32
165 " (%s) message is too long",
166 reply->type, nbd_rep_lookup(reply->type));
167 goto err;
168 }
169 msg = g_malloc(reply->length + 1);
170 if (nbd_read(ioc, msg, reply->length, NULL, errp) < 0) {
171 error_prepend(errp, "Failed to read option error %" PRIu32
172 " (%s) message: ",
173 reply->type, nbd_rep_lookup(reply->type));
174 goto err;
175 }
176 msg[reply->length] = '\0';
177 trace_nbd_server_error_msg(reply->type,
178 nbd_reply_type_lookup(reply->type), msg);
179 }
180
181 if (reply->type == NBD_REP_ERR_UNSUP || !strict) {
182 trace_nbd_reply_err_ignored(reply->option,
183 nbd_opt_lookup(reply->option),
184 reply->type, nbd_rep_lookup(reply->type));
185 return 0;
186 }
187
188 switch (reply->type) {
189 case NBD_REP_ERR_POLICY:
190 error_setg(errp, "Denied by server for option %" PRIu32 " (%s)",
191 reply->option, nbd_opt_lookup(reply->option));
192 break;
193
194 case NBD_REP_ERR_INVALID:
195 error_setg(errp, "Invalid parameters for option %" PRIu32 " (%s)",
196 reply->option, nbd_opt_lookup(reply->option));
197 break;
198
199 case NBD_REP_ERR_PLATFORM:
200 error_setg(errp, "Server lacks support for option %" PRIu32 " (%s)",
201 reply->option, nbd_opt_lookup(reply->option));
202 break;
203
204 case NBD_REP_ERR_TLS_REQD:
205 error_setg(errp, "TLS negotiation required before option %" PRIu32
206 " (%s)", reply->option, nbd_opt_lookup(reply->option));
207 error_append_hint(errp, "Did you forget a valid tls-creds?\n");
208 break;
209
210 case NBD_REP_ERR_UNKNOWN:
211 error_setg(errp, "Requested export not available");
212 break;
213
214 case NBD_REP_ERR_SHUTDOWN:
215 error_setg(errp, "Server shutting down before option %" PRIu32 " (%s)",
216 reply->option, nbd_opt_lookup(reply->option));
217 break;
218
219 case NBD_REP_ERR_BLOCK_SIZE_REQD:
220 error_setg(errp, "Server requires INFO_BLOCK_SIZE for option %" PRIu32
221 " (%s)", reply->option, nbd_opt_lookup(reply->option));
222 break;
223
224 default:
225 error_setg(errp, "Unknown error code when asking for option %" PRIu32
226 " (%s)", reply->option, nbd_opt_lookup(reply->option));
227 break;
228 }
229
230 if (msg) {
231 error_append_hint(errp, "server reported: %s\n", msg);
232 }
233
234 err:
235 nbd_send_opt_abort(ioc);
236 return -1;
237 }
238
239 /* nbd_receive_list:
240 * Process another portion of the NBD_OPT_LIST reply, populating any
241 * name received into *@name. If @description is non-NULL, and the
242 * server provided a description, that is also populated. The caller
243 * must eventually call g_free() on success.
244 * Returns 1 if name and description were set and iteration must continue,
245 * 0 if iteration is complete (including if OPT_LIST unsupported),
246 * -1 with @errp set if an unrecoverable error occurred.
247 */
248 static int nbd_receive_list(QIOChannel *ioc, char **name, char **description,
249 Error **errp)
250 {
251 NBDOptionReply reply;
252 uint32_t len;
253 uint32_t namelen;
254 g_autofree char *local_name = NULL;
255 g_autofree char *local_desc = NULL;
256 int error;
257
258 if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) {
259 return -1;
260 }
261 error = nbd_handle_reply_err(ioc, &reply, true, errp);
262 if (error <= 0) {
263 return error;
264 }
265 len = reply.length;
266
267 if (reply.type == NBD_REP_ACK) {
268 if (len != 0) {
269 error_setg(errp, "length too long for option end");
270 nbd_send_opt_abort(ioc);
271 return -1;
272 }
273 return 0;
274 } else if (reply.type != NBD_REP_SERVER) {
275 error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)",
276 reply.type, nbd_rep_lookup(reply.type),
277 NBD_REP_SERVER, nbd_rep_lookup(NBD_REP_SERVER));
278 nbd_send_opt_abort(ioc);
279 return -1;
280 }
281
282 if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) {
283 error_setg(errp, "incorrect option length %" PRIu32, len);
284 nbd_send_opt_abort(ioc);
285 return -1;
286 }
287 if (nbd_read32(ioc, &namelen, "option name length", errp) < 0) {
288 nbd_send_opt_abort(ioc);
289 return -1;
290 }
291 len -= sizeof(namelen);
292 if (len < namelen || namelen > NBD_MAX_STRING_SIZE) {
293 error_setg(errp, "incorrect name length in server's list response");
294 nbd_send_opt_abort(ioc);
295 return -1;
296 }
297
298 local_name = g_malloc(namelen + 1);
299 if (nbd_read(ioc, local_name, namelen, "export name", errp) < 0) {
300 nbd_send_opt_abort(ioc);
301 return -1;
302 }
303 local_name[namelen] = '\0';
304 len -= namelen;
305 if (len) {
306 if (len > NBD_MAX_STRING_SIZE) {
307 error_setg(errp, "incorrect description length in server's "
308 "list response");
309 nbd_send_opt_abort(ioc);
310 return -1;
311 }
312 local_desc = g_malloc(len + 1);
313 if (nbd_read(ioc, local_desc, len, "export description", errp) < 0) {
314 nbd_send_opt_abort(ioc);
315 return -1;
316 }
317 local_desc[len] = '\0';
318 }
319
320 trace_nbd_receive_list(local_name, local_desc ?: "");
321 *name = g_steal_pointer(&local_name);
322 if (description) {
323 *description = g_steal_pointer(&local_desc);
324 }
325 return 1;
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, true, 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 if (info->min_block &&
430 !QEMU_IS_ALIGNED(info->size, info->min_block)) {
431 error_setg(errp, "export size %" PRIu64 " is not multiple of "
432 "minimum block size %" PRIu32, info->size,
433 info->min_block);
434 nbd_send_opt_abort(ioc);
435 return -1;
436 }
437 trace_nbd_receive_negotiate_size_flags(info->size, info->flags);
438 break;
439
440 case NBD_INFO_BLOCK_SIZE:
441 if (len != sizeof(info->min_block) * 3) {
442 error_setg(errp, "remaining export info len %" PRIu32
443 " is unexpected size", len);
444 nbd_send_opt_abort(ioc);
445 return -1;
446 }
447 if (nbd_read32(ioc, &info->min_block, "info minimum block size",
448 errp) < 0) {
449 nbd_send_opt_abort(ioc);
450 return -1;
451 }
452 if (!is_power_of_2(info->min_block)) {
453 error_setg(errp, "server minimum block size %" PRIu32
454 " is not a power of two", info->min_block);
455 nbd_send_opt_abort(ioc);
456 return -1;
457 }
458 if (nbd_read32(ioc, &info->opt_block, "info preferred block size",
459 errp) < 0)
460 {
461 nbd_send_opt_abort(ioc);
462 return -1;
463 }
464 if (!is_power_of_2(info->opt_block) ||
465 info->opt_block < info->min_block) {
466 error_setg(errp, "server preferred block size %" PRIu32
467 " is not valid", info->opt_block);
468 nbd_send_opt_abort(ioc);
469 return -1;
470 }
471 if (nbd_read32(ioc, &info->max_block, "info maximum block size",
472 errp) < 0)
473 {
474 nbd_send_opt_abort(ioc);
475 return -1;
476 }
477 if (info->max_block < info->min_block) {
478 error_setg(errp, "server maximum block size %" PRIu32
479 " is not valid", info->max_block);
480 nbd_send_opt_abort(ioc);
481 return -1;
482 }
483 trace_nbd_opt_info_block_size(info->min_block, info->opt_block,
484 info->max_block);
485 break;
486
487 default:
488 /*
489 * Not worth the bother to check if NBD_INFO_NAME or
490 * NBD_INFO_DESCRIPTION exceed NBD_MAX_STRING_SIZE.
491 */
492 trace_nbd_opt_info_unknown(type, nbd_info_lookup(type));
493 if (nbd_drop(ioc, len, errp) < 0) {
494 error_prepend(errp, "Failed to read info payload: ");
495 nbd_send_opt_abort(ioc);
496 return -1;
497 }
498 break;
499 }
500 }
501 }
502
503 /* Return -1 on failure, 0 if wantname is an available export. */
504 static int nbd_receive_query_exports(QIOChannel *ioc,
505 const char *wantname,
506 Error **errp)
507 {
508 bool list_empty = true;
509 bool found_export = false;
510
511 trace_nbd_receive_query_exports_start(wantname);
512 if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) {
513 return -1;
514 }
515
516 while (1) {
517 char *name;
518 int ret = nbd_receive_list(ioc, &name, NULL, errp);
519
520 if (ret < 0) {
521 /* Server gave unexpected reply */
522 return -1;
523 } else if (ret == 0) {
524 /* Done iterating. */
525 if (list_empty) {
526 /*
527 * We don't have enough context to tell a server that
528 * sent an empty list apart from a server that does
529 * not support the list command; but as this function
530 * is just used to trigger a nicer error message
531 * before trying NBD_OPT_EXPORT_NAME, assume the
532 * export is available.
533 */
534 return 0;
535 } else if (!found_export) {
536 error_setg(errp, "No export with name '%s' available",
537 wantname);
538 nbd_send_opt_abort(ioc);
539 return -1;
540 }
541 trace_nbd_receive_query_exports_success(wantname);
542 return 0;
543 }
544 list_empty = false;
545 if (!strcmp(name, wantname)) {
546 found_export = true;
547 }
548 g_free(name);
549 }
550 }
551
552 /*
553 * nbd_request_simple_option: Send an option request, and parse the reply.
554 * @strict controls whether ERR_UNSUP or all errors produce 0 status.
555 * return 1 for successful negotiation,
556 * 0 if operation is unsupported,
557 * -1 with errp set for any other error
558 */
559 static int nbd_request_simple_option(QIOChannel *ioc, int opt, bool strict,
560 Error **errp)
561 {
562 NBDOptionReply reply;
563 int error;
564
565 if (nbd_send_option_request(ioc, opt, 0, NULL, errp) < 0) {
566 return -1;
567 }
568
569 if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) {
570 return -1;
571 }
572 error = nbd_handle_reply_err(ioc, &reply, strict, errp);
573 if (error <= 0) {
574 return error;
575 }
576
577 if (reply.type != NBD_REP_ACK) {
578 error_setg(errp, "Server answered option %d (%s) with unexpected "
579 "reply %" PRIu32 " (%s)", opt, nbd_opt_lookup(opt),
580 reply.type, nbd_rep_lookup(reply.type));
581 nbd_send_opt_abort(ioc);
582 return -1;
583 }
584
585 if (reply.length != 0) {
586 error_setg(errp, "Option %d ('%s') response length is %" PRIu32
587 " (it should be zero)", opt, nbd_opt_lookup(opt),
588 reply.length);
589 nbd_send_opt_abort(ioc);
590 return -1;
591 }
592
593 return 1;
594 }
595
596 static QIOChannel *nbd_receive_starttls(QIOChannel *ioc,
597 QCryptoTLSCreds *tlscreds,
598 const char *hostname, Error **errp)
599 {
600 int ret;
601 QIOChannelTLS *tioc;
602 struct NBDTLSHandshakeData data = { 0 };
603
604 ret = nbd_request_simple_option(ioc, NBD_OPT_STARTTLS, true, errp);
605 if (ret <= 0) {
606 if (ret == 0) {
607 error_setg(errp, "Server don't support STARTTLS option");
608 nbd_send_opt_abort(ioc);
609 }
610 return NULL;
611 }
612
613 trace_nbd_receive_starttls_new_client();
614 tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp);
615 if (!tioc) {
616 return NULL;
617 }
618 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-client-tls");
619 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
620 trace_nbd_receive_starttls_tls_handshake();
621 qio_channel_tls_handshake(tioc,
622 nbd_tls_handshake,
623 &data,
624 NULL,
625 NULL);
626
627 if (!data.complete) {
628 g_main_loop_run(data.loop);
629 }
630 g_main_loop_unref(data.loop);
631 if (data.error) {
632 error_propagate(errp, data.error);
633 object_unref(OBJECT(tioc));
634 return NULL;
635 }
636
637 return QIO_CHANNEL(tioc);
638 }
639
640 /*
641 * nbd_send_meta_query:
642 * Send 0 or 1 set/list meta context queries.
643 * Return 0 on success, -1 with errp set for any error
644 */
645 static int nbd_send_meta_query(QIOChannel *ioc, uint32_t opt,
646 const char *export, const char *query,
647 Error **errp)
648 {
649 int ret;
650 uint32_t export_len = strlen(export);
651 uint32_t queries = !!query;
652 uint32_t query_len = 0;
653 uint32_t data_len;
654 char *data;
655 char *p;
656
657 data_len = sizeof(export_len) + export_len + sizeof(queries);
658 assert(export_len <= NBD_MAX_STRING_SIZE);
659 if (query) {
660 query_len = strlen(query);
661 data_len += sizeof(query_len) + query_len;
662 assert(query_len <= NBD_MAX_STRING_SIZE);
663 } else {
664 assert(opt == NBD_OPT_LIST_META_CONTEXT);
665 }
666 p = data = g_malloc(data_len);
667
668 trace_nbd_opt_meta_request(nbd_opt_lookup(opt), query ?: "(all)", export);
669 stl_be_p(p, export_len);
670 memcpy(p += sizeof(export_len), export, export_len);
671 stl_be_p(p += export_len, queries);
672 if (query) {
673 stl_be_p(p += sizeof(queries), query_len);
674 memcpy(p += sizeof(query_len), query, query_len);
675 }
676
677 ret = nbd_send_option_request(ioc, opt, data_len, data, errp);
678 g_free(data);
679 return ret;
680 }
681
682 /*
683 * nbd_receive_one_meta_context:
684 * Called in a loop to receive and trace one set/list meta context reply.
685 * Pass non-NULL @name or @id to collect results back to the caller, which
686 * must eventually call g_free().
687 * return 1 if name is set and iteration must continue,
688 * 0 if iteration is complete (including if option is unsupported),
689 * -1 with errp set for any error
690 */
691 static int nbd_receive_one_meta_context(QIOChannel *ioc,
692 uint32_t opt,
693 char **name,
694 uint32_t *id,
695 Error **errp)
696 {
697 int ret;
698 NBDOptionReply reply;
699 char *local_name = NULL;
700 uint32_t local_id;
701
702 if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) {
703 return -1;
704 }
705
706 ret = nbd_handle_reply_err(ioc, &reply, false, errp);
707 if (ret <= 0) {
708 return ret;
709 }
710
711 if (reply.type == NBD_REP_ACK) {
712 if (reply.length != 0) {
713 error_setg(errp, "Unexpected length to ACK response");
714 nbd_send_opt_abort(ioc);
715 return -1;
716 }
717 return 0;
718 } else if (reply.type != NBD_REP_META_CONTEXT) {
719 error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)",
720 reply.type, nbd_rep_lookup(reply.type),
721 NBD_REP_META_CONTEXT, nbd_rep_lookup(NBD_REP_META_CONTEXT));
722 nbd_send_opt_abort(ioc);
723 return -1;
724 }
725
726 if (reply.length <= sizeof(local_id) ||
727 reply.length > NBD_MAX_BUFFER_SIZE) {
728 error_setg(errp, "Failed to negotiate meta context, server "
729 "answered with unexpected length %" PRIu32,
730 reply.length);
731 nbd_send_opt_abort(ioc);
732 return -1;
733 }
734
735 if (nbd_read32(ioc, &local_id, "context id", errp) < 0) {
736 return -1;
737 }
738
739 reply.length -= sizeof(local_id);
740 local_name = g_malloc(reply.length + 1);
741 if (nbd_read(ioc, local_name, reply.length, "context name", errp) < 0) {
742 g_free(local_name);
743 return -1;
744 }
745 local_name[reply.length] = '\0';
746 trace_nbd_opt_meta_reply(nbd_opt_lookup(opt), local_name, local_id);
747
748 if (name) {
749 *name = local_name;
750 } else {
751 g_free(local_name);
752 }
753 if (id) {
754 *id = local_id;
755 }
756 return 1;
757 }
758
759 /*
760 * nbd_negotiate_simple_meta_context:
761 * Request the server to set the meta context for export @info->name
762 * using @info->x_dirty_bitmap with a fallback to "base:allocation",
763 * setting @info->context_id to the resulting id. Fail if the server
764 * responds with more than one context or with a context different
765 * than the query.
766 * return 1 for successful negotiation,
767 * 0 if operation is unsupported,
768 * -1 with errp set for any other error
769 */
770 static int nbd_negotiate_simple_meta_context(QIOChannel *ioc,
771 NBDExportInfo *info,
772 Error **errp)
773 {
774 /*
775 * TODO: Removing the x_dirty_bitmap hack will mean refactoring
776 * this function to request and store ids for multiple contexts
777 * (both base:allocation and a dirty bitmap), at which point this
778 * function should lose the term _simple.
779 */
780 int ret;
781 const char *context = info->x_dirty_bitmap ?: "base:allocation";
782 bool received = false;
783 char *name = NULL;
784
785 if (nbd_send_meta_query(ioc, NBD_OPT_SET_META_CONTEXT,
786 info->name, context, errp) < 0) {
787 return -1;
788 }
789
790 ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT,
791 &name, &info->context_id, errp);
792 if (ret < 0) {
793 return -1;
794 }
795 if (ret == 1) {
796 if (strcmp(context, name)) {
797 error_setg(errp, "Failed to negotiate meta context '%s', server "
798 "answered with different context '%s'", context,
799 name);
800 g_free(name);
801 nbd_send_opt_abort(ioc);
802 return -1;
803 }
804 g_free(name);
805 received = true;
806
807 ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT,
808 NULL, NULL, errp);
809 if (ret < 0) {
810 return -1;
811 }
812 }
813 if (ret != 0) {
814 error_setg(errp, "Server answered with more than one context");
815 nbd_send_opt_abort(ioc);
816 return -1;
817 }
818 return received;
819 }
820
821 /*
822 * nbd_list_meta_contexts:
823 * Request the server to list all meta contexts for export @info->name.
824 * return 0 if list is complete (even if empty),
825 * -1 with errp set for any error
826 */
827 static int nbd_list_meta_contexts(QIOChannel *ioc,
828 NBDExportInfo *info,
829 Error **errp)
830 {
831 int ret;
832 int seen_any = false;
833 int seen_qemu = false;
834
835 if (nbd_send_meta_query(ioc, NBD_OPT_LIST_META_CONTEXT,
836 info->name, NULL, errp) < 0) {
837 return -1;
838 }
839
840 while (1) {
841 char *context;
842
843 ret = nbd_receive_one_meta_context(ioc, NBD_OPT_LIST_META_CONTEXT,
844 &context, NULL, errp);
845 if (ret == 0 && seen_any && !seen_qemu) {
846 /*
847 * Work around qemu 3.0 bug: the server forgot to send
848 * "qemu:" replies to 0 queries. If we saw at least one
849 * reply (probably base:allocation), but none of them were
850 * qemu:, then run a more specific query to make sure.
851 */
852 seen_qemu = true;
853 if (nbd_send_meta_query(ioc, NBD_OPT_LIST_META_CONTEXT,
854 info->name, "qemu:", errp) < 0) {
855 return -1;
856 }
857 continue;
858 }
859 if (ret <= 0) {
860 return ret;
861 }
862 seen_any = true;
863 seen_qemu |= strstart(context, "qemu:", NULL);
864 info->contexts = g_renew(char *, info->contexts, ++info->n_contexts);
865 info->contexts[info->n_contexts - 1] = context;
866 }
867 }
868
869 /*
870 * nbd_start_negotiate:
871 * Start the handshake to the server. After a positive return, the server
872 * is ready to accept additional NBD_OPT requests.
873 * Returns: negative errno: failure talking to server
874 * 0: server is oldstyle, must call nbd_negotiate_finish_oldstyle
875 * 1: server is newstyle, but can only accept EXPORT_NAME
876 * 2: server is newstyle, but lacks structured replies
877 * 3: server is newstyle and set up for structured replies
878 */
879 static int nbd_start_negotiate(AioContext *aio_context, QIOChannel *ioc,
880 QCryptoTLSCreds *tlscreds,
881 const char *hostname, QIOChannel **outioc,
882 bool structured_reply, bool *zeroes,
883 Error **errp)
884 {
885 uint64_t magic;
886
887 trace_nbd_start_negotiate(tlscreds, hostname ? hostname : "<null>");
888
889 if (zeroes) {
890 *zeroes = true;
891 }
892 if (outioc) {
893 *outioc = NULL;
894 }
895 if (tlscreds && !outioc) {
896 error_setg(errp, "Output I/O channel required for TLS");
897 return -EINVAL;
898 }
899
900 if (nbd_read64(ioc, &magic, "initial magic", errp) < 0) {
901 return -EINVAL;
902 }
903 trace_nbd_receive_negotiate_magic(magic);
904
905 if (magic != NBD_INIT_MAGIC) {
906 error_setg(errp, "Bad initial magic received: 0x%" PRIx64, magic);
907 return -EINVAL;
908 }
909
910 if (nbd_read64(ioc, &magic, "server magic", errp) < 0) {
911 return -EINVAL;
912 }
913 trace_nbd_receive_negotiate_magic(magic);
914
915 if (magic == NBD_OPTS_MAGIC) {
916 uint32_t clientflags = 0;
917 uint16_t globalflags;
918 bool fixedNewStyle = false;
919
920 if (nbd_read16(ioc, &globalflags, "server flags", errp) < 0) {
921 return -EINVAL;
922 }
923 trace_nbd_receive_negotiate_server_flags(globalflags);
924 if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) {
925 fixedNewStyle = true;
926 clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE;
927 }
928 if (globalflags & NBD_FLAG_NO_ZEROES) {
929 if (zeroes) {
930 *zeroes = false;
931 }
932 clientflags |= NBD_FLAG_C_NO_ZEROES;
933 }
934 /* client requested flags */
935 clientflags = cpu_to_be32(clientflags);
936 if (nbd_write(ioc, &clientflags, sizeof(clientflags), errp) < 0) {
937 error_prepend(errp, "Failed to send clientflags field: ");
938 return -EINVAL;
939 }
940 if (tlscreds) {
941 if (fixedNewStyle) {
942 *outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp);
943 if (!*outioc) {
944 return -EINVAL;
945 }
946 ioc = *outioc;
947 if (aio_context) {
948 qio_channel_set_blocking(ioc, false, NULL);
949 qio_channel_attach_aio_context(ioc, aio_context);
950 }
951 } else {
952 error_setg(errp, "Server does not support STARTTLS");
953 return -EINVAL;
954 }
955 }
956 if (fixedNewStyle) {
957 int result = 0;
958
959 if (structured_reply) {
960 result = nbd_request_simple_option(ioc,
961 NBD_OPT_STRUCTURED_REPLY,
962 false, errp);
963 if (result < 0) {
964 return -EINVAL;
965 }
966 }
967 return 2 + result;
968 } else {
969 return 1;
970 }
971 } else if (magic == NBD_CLIENT_MAGIC) {
972 if (tlscreds) {
973 error_setg(errp, "Server does not support STARTTLS");
974 return -EINVAL;
975 }
976 return 0;
977 } else {
978 error_setg(errp, "Bad server magic received: 0x%" PRIx64, magic);
979 return -EINVAL;
980 }
981 }
982
983 /*
984 * nbd_negotiate_finish_oldstyle:
985 * Populate @info with the size and export flags from an oldstyle server,
986 * but does not consume 124 bytes of reserved zero padding.
987 * Returns 0 on success, -1 with @errp set on failure
988 */
989 static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info,
990 Error **errp)
991 {
992 uint32_t oldflags;
993
994 if (nbd_read64(ioc, &info->size, "export length", errp) < 0) {
995 return -EINVAL;
996 }
997
998 if (nbd_read32(ioc, &oldflags, "export flags", errp) < 0) {
999 return -EINVAL;
1000 }
1001 if (oldflags & ~0xffff) {
1002 error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);
1003 return -EINVAL;
1004 }
1005 info->flags = oldflags;
1006 return 0;
1007 }
1008
1009 /*
1010 * nbd_receive_negotiate:
1011 * Connect to server, complete negotiation, and move into transmission phase.
1012 * Returns: negative errno: failure talking to server
1013 * 0: server is connected
1014 */
1015 int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
1016 QCryptoTLSCreds *tlscreds,
1017 const char *hostname, QIOChannel **outioc,
1018 NBDExportInfo *info, Error **errp)
1019 {
1020 int result;
1021 bool zeroes;
1022 bool base_allocation = info->base_allocation;
1023
1024 assert(info->name && strlen(info->name) <= NBD_MAX_STRING_SIZE);
1025 trace_nbd_receive_negotiate_name(info->name);
1026
1027 result = nbd_start_negotiate(aio_context, ioc, tlscreds, hostname, outioc,
1028 info->structured_reply, &zeroes, errp);
1029
1030 info->structured_reply = false;
1031 info->base_allocation = false;
1032 if (tlscreds && *outioc) {
1033 ioc = *outioc;
1034 }
1035
1036 switch (result) {
1037 case 3: /* newstyle, with structured replies */
1038 info->structured_reply = true;
1039 if (base_allocation) {
1040 result = nbd_negotiate_simple_meta_context(ioc, info, errp);
1041 if (result < 0) {
1042 return -EINVAL;
1043 }
1044 info->base_allocation = result == 1;
1045 }
1046 /* fall through */
1047 case 2: /* newstyle, try OPT_GO */
1048 /* Try NBD_OPT_GO first - if it works, we are done (it
1049 * also gives us a good message if the server requires
1050 * TLS). If it is not available, fall back to
1051 * NBD_OPT_LIST for nicer error messages about a missing
1052 * export, then use NBD_OPT_EXPORT_NAME. */
1053 result = nbd_opt_info_or_go(ioc, NBD_OPT_GO, info, errp);
1054 if (result < 0) {
1055 return -EINVAL;
1056 }
1057 if (result > 0) {
1058 return 0;
1059 }
1060 /* Check our desired export is present in the
1061 * server export list. Since NBD_OPT_EXPORT_NAME
1062 * cannot return an error message, running this
1063 * query gives us better error reporting if the
1064 * export name is not available.
1065 */
1066 if (nbd_receive_query_exports(ioc, info->name, errp) < 0) {
1067 return -EINVAL;
1068 }
1069 /* fall through */
1070 case 1: /* newstyle, but limited to EXPORT_NAME */
1071 /* write the export name request */
1072 if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, info->name,
1073 errp) < 0) {
1074 return -EINVAL;
1075 }
1076
1077 /* Read the response */
1078 if (nbd_read64(ioc, &info->size, "export length", errp) < 0) {
1079 return -EINVAL;
1080 }
1081
1082 if (nbd_read16(ioc, &info->flags, "export flags", errp) < 0) {
1083 return -EINVAL;
1084 }
1085 break;
1086 case 0: /* oldstyle, parse length and flags */
1087 if (*info->name) {
1088 error_setg(errp, "Server does not support non-empty export names");
1089 return -EINVAL;
1090 }
1091 if (nbd_negotiate_finish_oldstyle(ioc, info, errp) < 0) {
1092 return -EINVAL;
1093 }
1094 break;
1095 default:
1096 return result;
1097 }
1098
1099 trace_nbd_receive_negotiate_size_flags(info->size, info->flags);
1100 if (zeroes && nbd_drop(ioc, 124, errp) < 0) {
1101 error_prepend(errp, "Failed to read reserved block: ");
1102 return -EINVAL;
1103 }
1104 return 0;
1105 }
1106
1107 /* Clean up result of nbd_receive_export_list */
1108 void nbd_free_export_list(NBDExportInfo *info, int count)
1109 {
1110 int i, j;
1111
1112 if (!info) {
1113 return;
1114 }
1115
1116 for (i = 0; i < count; i++) {
1117 g_free(info[i].name);
1118 g_free(info[i].description);
1119 for (j = 0; j < info[i].n_contexts; j++) {
1120 g_free(info[i].contexts[j]);
1121 }
1122 g_free(info[i].contexts);
1123 }
1124 g_free(info);
1125 }
1126
1127 /*
1128 * nbd_receive_export_list:
1129 * Query details about a server's exports, then disconnect without
1130 * going into transmission phase. Return a count of the exports listed
1131 * in @info by the server, or -1 on error. Caller must free @info using
1132 * nbd_free_export_list().
1133 */
1134 int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
1135 const char *hostname, NBDExportInfo **info,
1136 Error **errp)
1137 {
1138 int result;
1139 int count = 0;
1140 int i;
1141 int rc;
1142 int ret = -1;
1143 NBDExportInfo *array = NULL;
1144 QIOChannel *sioc = NULL;
1145
1146 *info = NULL;
1147 result = nbd_start_negotiate(NULL, ioc, tlscreds, hostname, &sioc, true,
1148 NULL, errp);
1149 if (tlscreds && sioc) {
1150 ioc = sioc;
1151 }
1152
1153 switch (result) {
1154 case 2:
1155 case 3:
1156 /* newstyle - use NBD_OPT_LIST to populate array, then try
1157 * NBD_OPT_INFO on each array member. If structured replies
1158 * are enabled, also try NBD_OPT_LIST_META_CONTEXT. */
1159 if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) {
1160 goto out;
1161 }
1162 while (1) {
1163 char *name;
1164 char *desc;
1165
1166 rc = nbd_receive_list(ioc, &name, &desc, errp);
1167 if (rc < 0) {
1168 goto out;
1169 } else if (rc == 0) {
1170 break;
1171 }
1172 array = g_renew(NBDExportInfo, array, ++count);
1173 memset(&array[count - 1], 0, sizeof(*array));
1174 array[count - 1].name = name;
1175 array[count - 1].description = desc;
1176 array[count - 1].structured_reply = result == 3;
1177 }
1178
1179 for (i = 0; i < count; i++) {
1180 array[i].request_sizes = true;
1181 rc = nbd_opt_info_or_go(ioc, NBD_OPT_INFO, &array[i], errp);
1182 if (rc < 0) {
1183 goto out;
1184 } else if (rc == 0) {
1185 /*
1186 * Pointless to try rest of loop. If OPT_INFO doesn't work,
1187 * it's unlikely that meta contexts work either
1188 */
1189 break;
1190 }
1191
1192 if (result == 3 &&
1193 nbd_list_meta_contexts(ioc, &array[i], errp) < 0) {
1194 goto out;
1195 }
1196 }
1197
1198 /* Send NBD_OPT_ABORT as a courtesy before hanging up */
1199 nbd_send_opt_abort(ioc);
1200 break;
1201 case 1: /* newstyle, but limited to EXPORT_NAME */
1202 error_setg(errp, "Server does not support export lists");
1203 /* We can't even send NBD_OPT_ABORT, so merely hang up */
1204 goto out;
1205 case 0: /* oldstyle, parse length and flags */
1206 array = g_new0(NBDExportInfo, 1);
1207 array->name = g_strdup("");
1208 count = 1;
1209
1210 if (nbd_negotiate_finish_oldstyle(ioc, array, errp) < 0) {
1211 goto out;
1212 }
1213
1214 /* Send NBD_CMD_DISC as a courtesy to the server, but ignore all
1215 * errors now that we have the information we wanted. */
1216 if (nbd_drop(ioc, 124, NULL) == 0) {
1217 NBDRequest request = { .type = NBD_CMD_DISC };
1218
1219 nbd_send_request(ioc, &request);
1220 }
1221 break;
1222 default:
1223 goto out;
1224 }
1225
1226 *info = array;
1227 array = NULL;
1228 ret = count;
1229
1230 out:
1231 qio_channel_shutdown(ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
1232 qio_channel_close(ioc, NULL);
1233 object_unref(OBJECT(sioc));
1234 nbd_free_export_list(array, count);
1235 return ret;
1236 }
1237
1238 #ifdef __linux__
1239 int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info,
1240 Error **errp)
1241 {
1242 unsigned long sector_size = MAX(BDRV_SECTOR_SIZE, info->min_block);
1243 unsigned long sectors = info->size / sector_size;
1244
1245 /* FIXME: Once the kernel module is patched to honor block sizes,
1246 * and to advertise that fact to user space, we should update the
1247 * hand-off to the kernel to use any block sizes we learned. */
1248 assert(!info->request_sizes);
1249 if (info->size / sector_size != sectors) {
1250 error_setg(errp, "Export size %" PRIu64 " too large for 32-bit kernel",
1251 info->size);
1252 return -E2BIG;
1253 }
1254
1255 trace_nbd_init_set_socket();
1256
1257 if (ioctl(fd, NBD_SET_SOCK, (unsigned long) sioc->fd) < 0) {
1258 int serrno = errno;
1259 error_setg(errp, "Failed to set NBD socket");
1260 return -serrno;
1261 }
1262
1263 trace_nbd_init_set_block_size(sector_size);
1264
1265 if (ioctl(fd, NBD_SET_BLKSIZE, sector_size) < 0) {
1266 int serrno = errno;
1267 error_setg(errp, "Failed setting NBD block size");
1268 return -serrno;
1269 }
1270
1271 trace_nbd_init_set_size(sectors);
1272 if (info->size % sector_size) {
1273 trace_nbd_init_trailing_bytes(info->size % sector_size);
1274 }
1275
1276 if (ioctl(fd, NBD_SET_SIZE_BLOCKS, sectors) < 0) {
1277 int serrno = errno;
1278 error_setg(errp, "Failed setting size (in blocks)");
1279 return -serrno;
1280 }
1281
1282 if (ioctl(fd, NBD_SET_FLAGS, (unsigned long) info->flags) < 0) {
1283 if (errno == ENOTTY) {
1284 int read_only = (info->flags & NBD_FLAG_READ_ONLY) != 0;
1285 trace_nbd_init_set_readonly();
1286
1287 if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
1288 int serrno = errno;
1289 error_setg(errp, "Failed setting read-only attribute");
1290 return -serrno;
1291 }
1292 } else {
1293 int serrno = errno;
1294 error_setg(errp, "Failed setting flags");
1295 return -serrno;
1296 }
1297 }
1298
1299 trace_nbd_init_finish();
1300
1301 return 0;
1302 }
1303
1304 int nbd_client(int fd)
1305 {
1306 int ret;
1307 int serrno;
1308
1309 trace_nbd_client_loop();
1310
1311 ret = ioctl(fd, NBD_DO_IT);
1312 if (ret < 0 && errno == EPIPE) {
1313 /* NBD_DO_IT normally returns EPIPE when someone has disconnected
1314 * the socket via NBD_DISCONNECT. We do not want to return 1 in
1315 * that case.
1316 */
1317 ret = 0;
1318 }
1319 serrno = errno;
1320
1321 trace_nbd_client_loop_ret(ret, strerror(serrno));
1322
1323 trace_nbd_client_clear_queue();
1324 ioctl(fd, NBD_CLEAR_QUE);
1325
1326 trace_nbd_client_clear_socket();
1327 ioctl(fd, NBD_CLEAR_SOCK);
1328
1329 errno = serrno;
1330 return ret;
1331 }
1332
1333 int nbd_disconnect(int fd)
1334 {
1335 ioctl(fd, NBD_CLEAR_QUE);
1336 ioctl(fd, NBD_DISCONNECT);
1337 ioctl(fd, NBD_CLEAR_SOCK);
1338 return 0;
1339 }
1340
1341 #endif /* __linux__ */
1342
1343 int nbd_send_request(QIOChannel *ioc, NBDRequest *request)
1344 {
1345 uint8_t buf[NBD_REQUEST_SIZE];
1346
1347 trace_nbd_send_request(request->from, request->len, request->handle,
1348 request->flags, request->type,
1349 nbd_cmd_lookup(request->type));
1350
1351 stl_be_p(buf, NBD_REQUEST_MAGIC);
1352 stw_be_p(buf + 4, request->flags);
1353 stw_be_p(buf + 6, request->type);
1354 stq_be_p(buf + 8, request->handle);
1355 stq_be_p(buf + 16, request->from);
1356 stl_be_p(buf + 24, request->len);
1357
1358 return nbd_write(ioc, buf, sizeof(buf), NULL);
1359 }
1360
1361 /* nbd_receive_simple_reply
1362 * Read simple reply except magic field (which should be already read).
1363 * Payload is not read (payload is possible for CMD_READ, but here we even
1364 * don't know whether it take place or not).
1365 */
1366 static int nbd_receive_simple_reply(QIOChannel *ioc, NBDSimpleReply *reply,
1367 Error **errp)
1368 {
1369 int ret;
1370
1371 assert(reply->magic == NBD_SIMPLE_REPLY_MAGIC);
1372
1373 ret = nbd_read(ioc, (uint8_t *)reply + sizeof(reply->magic),
1374 sizeof(*reply) - sizeof(reply->magic), "reply", errp);
1375 if (ret < 0) {
1376 return ret;
1377 }
1378
1379 reply->error = be32_to_cpu(reply->error);
1380 reply->handle = be64_to_cpu(reply->handle);
1381
1382 return 0;
1383 }
1384
1385 /* nbd_receive_structured_reply_chunk
1386 * Read structured reply chunk except magic field (which should be already
1387 * read).
1388 * Payload is not read.
1389 */
1390 static int nbd_receive_structured_reply_chunk(QIOChannel *ioc,
1391 NBDStructuredReplyChunk *chunk,
1392 Error **errp)
1393 {
1394 int ret;
1395
1396 assert(chunk->magic == NBD_STRUCTURED_REPLY_MAGIC);
1397
1398 ret = nbd_read(ioc, (uint8_t *)chunk + sizeof(chunk->magic),
1399 sizeof(*chunk) - sizeof(chunk->magic), "structured chunk",
1400 errp);
1401 if (ret < 0) {
1402 return ret;
1403 }
1404
1405 chunk->flags = be16_to_cpu(chunk->flags);
1406 chunk->type = be16_to_cpu(chunk->type);
1407 chunk->handle = be64_to_cpu(chunk->handle);
1408 chunk->length = be32_to_cpu(chunk->length);
1409
1410 return 0;
1411 }
1412
1413 /* nbd_read_eof
1414 * Tries to read @size bytes from @ioc.
1415 * Returns 1 on success
1416 * 0 on eof, when no data was read (errp is not set)
1417 * negative errno on failure (errp is set)
1418 */
1419 static inline int coroutine_fn
1420 nbd_read_eof(BlockDriverState *bs, QIOChannel *ioc, void *buffer, size_t size,
1421 Error **errp)
1422 {
1423 bool partial = false;
1424
1425 assert(size);
1426 while (size > 0) {
1427 struct iovec iov = { .iov_base = buffer, .iov_len = size };
1428 ssize_t len;
1429
1430 len = qio_channel_readv(ioc, &iov, 1, errp);
1431 if (len == QIO_CHANNEL_ERR_BLOCK) {
1432 bdrv_dec_in_flight(bs);
1433 qio_channel_yield(ioc, G_IO_IN);
1434 bdrv_inc_in_flight(bs);
1435 continue;
1436 } else if (len < 0) {
1437 return -EIO;
1438 } else if (len == 0) {
1439 if (partial) {
1440 error_setg(errp,
1441 "Unexpected end-of-file before all bytes were read");
1442 return -EIO;
1443 } else {
1444 return 0;
1445 }
1446 }
1447
1448 partial = true;
1449 size -= len;
1450 buffer = (uint8_t*) buffer + len;
1451 }
1452 return 1;
1453 }
1454
1455 /* nbd_receive_reply
1456 *
1457 * Decreases bs->in_flight while waiting for a new reply. This yield is where
1458 * we wait indefinitely and the coroutine must be able to be safely reentered
1459 * for nbd_client_attach_aio_context().
1460 *
1461 * Returns 1 on success
1462 * 0 on eof, when no data was read (errp is not set)
1463 * negative errno on failure (errp is set)
1464 */
1465 int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc,
1466 NBDReply *reply, Error **errp)
1467 {
1468 int ret;
1469 const char *type;
1470
1471 ret = nbd_read_eof(bs, ioc, &reply->magic, sizeof(reply->magic), errp);
1472 if (ret <= 0) {
1473 return ret;
1474 }
1475
1476 reply->magic = be32_to_cpu(reply->magic);
1477
1478 switch (reply->magic) {
1479 case NBD_SIMPLE_REPLY_MAGIC:
1480 ret = nbd_receive_simple_reply(ioc, &reply->simple, errp);
1481 if (ret < 0) {
1482 break;
1483 }
1484 trace_nbd_receive_simple_reply(reply->simple.error,
1485 nbd_err_lookup(reply->simple.error),
1486 reply->handle);
1487 break;
1488 case NBD_STRUCTURED_REPLY_MAGIC:
1489 ret = nbd_receive_structured_reply_chunk(ioc, &reply->structured, errp);
1490 if (ret < 0) {
1491 break;
1492 }
1493 type = nbd_reply_type_lookup(reply->structured.type);
1494 trace_nbd_receive_structured_reply_chunk(reply->structured.flags,
1495 reply->structured.type, type,
1496 reply->structured.handle,
1497 reply->structured.length);
1498 break;
1499 default:
1500 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", reply->magic);
1501 return -EINVAL;
1502 }
1503 if (ret < 0) {
1504 return ret;
1505 }
1506
1507 return 1;
1508 }
1509