nbd: More debug typo fixes, use correct formats
[qemu.git] / nbd / server.c
1 /*
2 * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
3 *
4 * Network Block Device Server Side
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; under version 2 of the License.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, see <http://www.gnu.org/licenses/>.
17 */
18
19 #include "qemu/osdep.h"
20 #include "qapi/error.h"
21 #include "nbd-internal.h"
22
23 static int system_errno_to_nbd_errno(int err)
24 {
25 switch (err) {
26 case 0:
27 return NBD_SUCCESS;
28 case EPERM:
29 case EROFS:
30 return NBD_EPERM;
31 case EIO:
32 return NBD_EIO;
33 case ENOMEM:
34 return NBD_ENOMEM;
35 #ifdef EDQUOT
36 case EDQUOT:
37 #endif
38 case EFBIG:
39 case ENOSPC:
40 return NBD_ENOSPC;
41 case EINVAL:
42 default:
43 return NBD_EINVAL;
44 }
45 }
46
47 /* Definitions for opaque data types */
48
49 typedef struct NBDRequest NBDRequest;
50
51 struct NBDRequest {
52 QSIMPLEQ_ENTRY(NBDRequest) entry;
53 NBDClient *client;
54 uint8_t *data;
55 };
56
57 struct NBDExport {
58 int refcount;
59 void (*close)(NBDExport *exp);
60
61 BlockBackend *blk;
62 char *name;
63 off_t dev_offset;
64 off_t size;
65 uint32_t nbdflags;
66 QTAILQ_HEAD(, NBDClient) clients;
67 QTAILQ_ENTRY(NBDExport) next;
68
69 AioContext *ctx;
70
71 Notifier eject_notifier;
72 };
73
74 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
75
76 struct NBDClient {
77 int refcount;
78 void (*close)(NBDClient *client);
79
80 NBDExport *exp;
81 QCryptoTLSCreds *tlscreds;
82 char *tlsaclname;
83 QIOChannelSocket *sioc; /* The underlying data channel */
84 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
85
86 Coroutine *recv_coroutine;
87
88 CoMutex send_lock;
89 Coroutine *send_coroutine;
90
91 bool can_read;
92
93 QTAILQ_ENTRY(NBDClient) next;
94 int nb_requests;
95 bool closing;
96 };
97
98 /* That's all folks */
99
100 static void nbd_set_handlers(NBDClient *client);
101 static void nbd_unset_handlers(NBDClient *client);
102 static void nbd_update_can_read(NBDClient *client);
103
104 static gboolean nbd_negotiate_continue(QIOChannel *ioc,
105 GIOCondition condition,
106 void *opaque)
107 {
108 qemu_coroutine_enter(opaque, NULL);
109 return TRUE;
110 }
111
112 static ssize_t nbd_negotiate_read(QIOChannel *ioc, void *buffer, size_t size)
113 {
114 ssize_t ret;
115 guint watch;
116
117 assert(qemu_in_coroutine());
118 /* Negotiation are always in main loop. */
119 watch = qio_channel_add_watch(ioc,
120 G_IO_IN,
121 nbd_negotiate_continue,
122 qemu_coroutine_self(),
123 NULL);
124 ret = read_sync(ioc, buffer, size);
125 g_source_remove(watch);
126 return ret;
127
128 }
129
130 static ssize_t nbd_negotiate_write(QIOChannel *ioc, void *buffer, size_t size)
131 {
132 ssize_t ret;
133 guint watch;
134
135 assert(qemu_in_coroutine());
136 /* Negotiation are always in main loop. */
137 watch = qio_channel_add_watch(ioc,
138 G_IO_OUT,
139 nbd_negotiate_continue,
140 qemu_coroutine_self(),
141 NULL);
142 ret = write_sync(ioc, buffer, size);
143 g_source_remove(watch);
144 return ret;
145 }
146
147 static ssize_t nbd_negotiate_drop_sync(QIOChannel *ioc, size_t size)
148 {
149 ssize_t ret, dropped = size;
150 uint8_t *buffer = g_malloc(MIN(65536, size));
151
152 while (size > 0) {
153 ret = nbd_negotiate_read(ioc, buffer, MIN(65536, size));
154 if (ret < 0) {
155 g_free(buffer);
156 return ret;
157 }
158
159 assert(ret <= size);
160 size -= ret;
161 }
162
163 g_free(buffer);
164 return dropped;
165 }
166
167 /* Basic flow for negotiation
168
169 Server Client
170 Negotiate
171
172 or
173
174 Server Client
175 Negotiate #1
176 Option
177 Negotiate #2
178
179 ----
180
181 followed by
182
183 Server Client
184 Request
185 Response
186 Request
187 Response
188 ...
189 ...
190 Request (type == 2)
191
192 */
193
194 static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
195 {
196 uint64_t magic;
197 uint32_t len;
198
199 TRACE("Reply opt=%" PRIx32 " type=%" PRIx32, type, opt);
200
201 magic = cpu_to_be64(NBD_REP_MAGIC);
202 if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
203 LOG("write failed (rep magic)");
204 return -EINVAL;
205 }
206 opt = cpu_to_be32(opt);
207 if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
208 LOG("write failed (rep opt)");
209 return -EINVAL;
210 }
211 type = cpu_to_be32(type);
212 if (nbd_negotiate_write(ioc, &type, sizeof(type)) != sizeof(type)) {
213 LOG("write failed (rep type)");
214 return -EINVAL;
215 }
216 len = cpu_to_be32(0);
217 if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
218 LOG("write failed (rep data length)");
219 return -EINVAL;
220 }
221 return 0;
222 }
223
224 static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
225 {
226 uint64_t magic, name_len;
227 uint32_t opt, type, len;
228
229 TRACE("Advertising export name '%s'", exp->name ? exp->name : "");
230 name_len = strlen(exp->name);
231 magic = cpu_to_be64(NBD_REP_MAGIC);
232 if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
233 LOG("write failed (magic)");
234 return -EINVAL;
235 }
236 opt = cpu_to_be32(NBD_OPT_LIST);
237 if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
238 LOG("write failed (opt)");
239 return -EINVAL;
240 }
241 type = cpu_to_be32(NBD_REP_SERVER);
242 if (nbd_negotiate_write(ioc, &type, sizeof(type)) != sizeof(type)) {
243 LOG("write failed (reply type)");
244 return -EINVAL;
245 }
246 len = cpu_to_be32(name_len + sizeof(len));
247 if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
248 LOG("write failed (length)");
249 return -EINVAL;
250 }
251 len = cpu_to_be32(name_len);
252 if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
253 LOG("write failed (length)");
254 return -EINVAL;
255 }
256 if (nbd_negotiate_write(ioc, exp->name, name_len) != name_len) {
257 LOG("write failed (buffer)");
258 return -EINVAL;
259 }
260 return 0;
261 }
262
263 static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length)
264 {
265 NBDExport *exp;
266
267 if (length) {
268 if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
269 return -EIO;
270 }
271 return nbd_negotiate_send_rep(client->ioc,
272 NBD_REP_ERR_INVALID, NBD_OPT_LIST);
273 }
274
275 /* For each export, send a NBD_REP_SERVER reply. */
276 QTAILQ_FOREACH(exp, &exports, next) {
277 if (nbd_negotiate_send_rep_list(client->ioc, exp)) {
278 return -EINVAL;
279 }
280 }
281 /* Finish with a NBD_REP_ACK. */
282 return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST);
283 }
284
285 static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length)
286 {
287 int rc = -EINVAL;
288 char name[256];
289
290 /* Client sends:
291 [20 .. xx] export name (length bytes)
292 */
293 TRACE("Checking length");
294 if (length > 255) {
295 LOG("Bad length received");
296 goto fail;
297 }
298 if (nbd_negotiate_read(client->ioc, name, length) != length) {
299 LOG("read failed");
300 goto fail;
301 }
302 name[length] = '\0';
303
304 TRACE("Client requested export '%s'", name);
305
306 client->exp = nbd_export_find(name);
307 if (!client->exp) {
308 LOG("export not found");
309 goto fail;
310 }
311
312 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
313 nbd_export_get(client->exp);
314 rc = 0;
315 fail:
316 return rc;
317 }
318
319
320 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
321 uint32_t length)
322 {
323 QIOChannel *ioc;
324 QIOChannelTLS *tioc;
325 struct NBDTLSHandshakeData data = { 0 };
326
327 TRACE("Setting up TLS");
328 ioc = client->ioc;
329 if (length) {
330 if (nbd_negotiate_drop_sync(ioc, length) != length) {
331 return NULL;
332 }
333 nbd_negotiate_send_rep(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS);
334 return NULL;
335 }
336
337 nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_STARTTLS);
338
339 tioc = qio_channel_tls_new_server(ioc,
340 client->tlscreds,
341 client->tlsaclname,
342 NULL);
343 if (!tioc) {
344 return NULL;
345 }
346
347 TRACE("Starting TLS handshake");
348 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
349 qio_channel_tls_handshake(tioc,
350 nbd_tls_handshake,
351 &data,
352 NULL);
353
354 if (!data.complete) {
355 g_main_loop_run(data.loop);
356 }
357 g_main_loop_unref(data.loop);
358 if (data.error) {
359 object_unref(OBJECT(tioc));
360 error_free(data.error);
361 return NULL;
362 }
363
364 return QIO_CHANNEL(tioc);
365 }
366
367
368 static int nbd_negotiate_options(NBDClient *client)
369 {
370 uint32_t flags;
371 bool fixedNewstyle = false;
372
373 /* Client sends:
374 [ 0 .. 3] client flags
375
376 [ 0 .. 7] NBD_OPTS_MAGIC
377 [ 8 .. 11] NBD option
378 [12 .. 15] Data length
379 ... Rest of request
380
381 [ 0 .. 7] NBD_OPTS_MAGIC
382 [ 8 .. 11] Second NBD option
383 [12 .. 15] Data length
384 ... Rest of request
385 */
386
387 if (nbd_negotiate_read(client->ioc, &flags, sizeof(flags)) !=
388 sizeof(flags)) {
389 LOG("read failed");
390 return -EIO;
391 }
392 TRACE("Checking client flags");
393 be32_to_cpus(&flags);
394 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
395 TRACE("Client supports fixed newstyle handshake");
396 fixedNewstyle = true;
397 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
398 }
399 if (flags != 0) {
400 TRACE("Unknown client flags 0x%" PRIx32 " received", flags);
401 return -EIO;
402 }
403
404 while (1) {
405 int ret;
406 uint32_t clientflags, length;
407 uint64_t magic;
408
409 if (nbd_negotiate_read(client->ioc, &magic, sizeof(magic)) !=
410 sizeof(magic)) {
411 LOG("read failed");
412 return -EINVAL;
413 }
414 TRACE("Checking opts magic");
415 if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) {
416 LOG("Bad magic received");
417 return -EINVAL;
418 }
419
420 if (nbd_negotiate_read(client->ioc, &clientflags,
421 sizeof(clientflags)) != sizeof(clientflags)) {
422 LOG("read failed");
423 return -EINVAL;
424 }
425 clientflags = be32_to_cpu(clientflags);
426
427 if (nbd_negotiate_read(client->ioc, &length, sizeof(length)) !=
428 sizeof(length)) {
429 LOG("read failed");
430 return -EINVAL;
431 }
432 length = be32_to_cpu(length);
433
434 TRACE("Checking option 0x%" PRIx32, clientflags);
435 if (client->tlscreds &&
436 client->ioc == (QIOChannel *)client->sioc) {
437 QIOChannel *tioc;
438 if (!fixedNewstyle) {
439 TRACE("Unsupported option 0x%" PRIx32, clientflags);
440 return -EINVAL;
441 }
442 switch (clientflags) {
443 case NBD_OPT_STARTTLS:
444 tioc = nbd_negotiate_handle_starttls(client, length);
445 if (!tioc) {
446 return -EIO;
447 }
448 object_unref(OBJECT(client->ioc));
449 client->ioc = QIO_CHANNEL(tioc);
450 break;
451
452 case NBD_OPT_EXPORT_NAME:
453 /* No way to return an error to client, so drop connection */
454 TRACE("Option 0x%x not permitted before TLS", clientflags);
455 return -EINVAL;
456
457 default:
458 TRACE("Option 0x%" PRIx32 " not permitted before TLS",
459 clientflags);
460 if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
461 return -EIO;
462 }
463 nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_TLS_REQD,
464 clientflags);
465 break;
466 }
467 } else if (fixedNewstyle) {
468 switch (clientflags) {
469 case NBD_OPT_LIST:
470 ret = nbd_negotiate_handle_list(client, length);
471 if (ret < 0) {
472 return ret;
473 }
474 break;
475
476 case NBD_OPT_ABORT:
477 return -EINVAL;
478
479 case NBD_OPT_EXPORT_NAME:
480 return nbd_negotiate_handle_export_name(client, length);
481
482 case NBD_OPT_STARTTLS:
483 if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
484 return -EIO;
485 }
486 if (client->tlscreds) {
487 TRACE("TLS already enabled");
488 nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_INVALID,
489 clientflags);
490 } else {
491 TRACE("TLS not configured");
492 nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_POLICY,
493 clientflags);
494 }
495 break;
496 default:
497 TRACE("Unsupported option 0x%" PRIx32, clientflags);
498 if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
499 return -EIO;
500 }
501 nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_UNSUP,
502 clientflags);
503 break;
504 }
505 } else {
506 /*
507 * If broken new-style we should drop the connection
508 * for anything except NBD_OPT_EXPORT_NAME
509 */
510 switch (clientflags) {
511 case NBD_OPT_EXPORT_NAME:
512 return nbd_negotiate_handle_export_name(client, length);
513
514 default:
515 TRACE("Unsupported option 0x%" PRIx32, clientflags);
516 return -EINVAL;
517 }
518 }
519 }
520 }
521
522 typedef struct {
523 NBDClient *client;
524 Coroutine *co;
525 } NBDClientNewData;
526
527 static coroutine_fn int nbd_negotiate(NBDClientNewData *data)
528 {
529 NBDClient *client = data->client;
530 char buf[8 + 8 + 8 + 128];
531 int rc;
532 const int myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
533 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA);
534 bool oldStyle;
535
536 /* Old style negotiation header without options
537 [ 0 .. 7] passwd ("NBDMAGIC")
538 [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
539 [16 .. 23] size
540 [24 .. 25] server flags (0)
541 [26 .. 27] export flags
542 [28 .. 151] reserved (0)
543
544 New style negotiation header with options
545 [ 0 .. 7] passwd ("NBDMAGIC")
546 [ 8 .. 15] magic (NBD_OPTS_MAGIC)
547 [16 .. 17] server flags (0)
548 ....options sent....
549 [18 .. 25] size
550 [26 .. 27] export flags
551 [28 .. 151] reserved (0)
552 */
553
554 qio_channel_set_blocking(client->ioc, false, NULL);
555 rc = -EINVAL;
556
557 TRACE("Beginning negotiation.");
558 memset(buf, 0, sizeof(buf));
559 memcpy(buf, "NBDMAGIC", 8);
560
561 oldStyle = client->exp != NULL && !client->tlscreds;
562 if (oldStyle) {
563 assert ((client->exp->nbdflags & ~65535) == 0);
564 TRACE("advertising size %" PRIu64 " and flags %x",
565 client->exp->size, client->exp->nbdflags | myflags);
566 stq_be_p(buf + 8, NBD_CLIENT_MAGIC);
567 stq_be_p(buf + 16, client->exp->size);
568 stw_be_p(buf + 26, client->exp->nbdflags | myflags);
569 } else {
570 stq_be_p(buf + 8, NBD_OPTS_MAGIC);
571 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE);
572 }
573
574 if (oldStyle) {
575 if (client->tlscreds) {
576 TRACE("TLS cannot be enabled with oldstyle protocol");
577 goto fail;
578 }
579 if (nbd_negotiate_write(client->ioc, buf, sizeof(buf)) != sizeof(buf)) {
580 LOG("write failed");
581 goto fail;
582 }
583 } else {
584 if (nbd_negotiate_write(client->ioc, buf, 18) != 18) {
585 LOG("write failed");
586 goto fail;
587 }
588 rc = nbd_negotiate_options(client);
589 if (rc != 0) {
590 LOG("option negotiation failed");
591 goto fail;
592 }
593
594 assert ((client->exp->nbdflags & ~65535) == 0);
595 TRACE("advertising size %" PRIu64 " and flags %x",
596 client->exp->size, client->exp->nbdflags | myflags);
597 stq_be_p(buf + 18, client->exp->size);
598 stw_be_p(buf + 26, client->exp->nbdflags | myflags);
599 if (nbd_negotiate_write(client->ioc, buf + 18, sizeof(buf) - 18) !=
600 sizeof(buf) - 18) {
601 LOG("write failed");
602 goto fail;
603 }
604 }
605
606 TRACE("Negotiation succeeded.");
607 rc = 0;
608 fail:
609 return rc;
610 }
611
612 #ifdef __linux__
613
614 int nbd_disconnect(int fd)
615 {
616 ioctl(fd, NBD_CLEAR_QUE);
617 ioctl(fd, NBD_DISCONNECT);
618 ioctl(fd, NBD_CLEAR_SOCK);
619 return 0;
620 }
621
622 #else
623
624 int nbd_disconnect(int fd)
625 {
626 return -ENOTSUP;
627 }
628 #endif
629
630 static ssize_t nbd_receive_request(QIOChannel *ioc, struct nbd_request *request)
631 {
632 uint8_t buf[NBD_REQUEST_SIZE];
633 uint32_t magic;
634 ssize_t ret;
635
636 ret = read_sync(ioc, buf, sizeof(buf));
637 if (ret < 0) {
638 return ret;
639 }
640
641 if (ret != sizeof(buf)) {
642 LOG("read failed");
643 return -EINVAL;
644 }
645
646 /* Request
647 [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
648 [ 4 .. 7] type (0 == READ, 1 == WRITE)
649 [ 8 .. 15] handle
650 [16 .. 23] from
651 [24 .. 27] len
652 */
653
654 magic = ldl_be_p(buf);
655 request->type = ldl_be_p(buf + 4);
656 request->handle = ldq_be_p(buf + 8);
657 request->from = ldq_be_p(buf + 16);
658 request->len = ldl_be_p(buf + 24);
659
660 TRACE("Got request: { magic = 0x%" PRIx32 ", .type = %" PRIx32
661 ", from = %" PRIu64 " , len = %" PRIu32 " }",
662 magic, request->type, request->from, request->len);
663
664 if (magic != NBD_REQUEST_MAGIC) {
665 LOG("invalid magic (got 0x%" PRIx32 ")", magic);
666 return -EINVAL;
667 }
668 return 0;
669 }
670
671 static ssize_t nbd_send_reply(QIOChannel *ioc, struct nbd_reply *reply)
672 {
673 uint8_t buf[NBD_REPLY_SIZE];
674 ssize_t ret;
675
676 reply->error = system_errno_to_nbd_errno(reply->error);
677
678 TRACE("Sending response to client: { .error = %" PRId32
679 ", handle = %" PRIu64 " }",
680 reply->error, reply->handle);
681
682 /* Reply
683 [ 0 .. 3] magic (NBD_REPLY_MAGIC)
684 [ 4 .. 7] error (0 == no error)
685 [ 7 .. 15] handle
686 */
687 stl_be_p(buf, NBD_REPLY_MAGIC);
688 stl_be_p(buf + 4, reply->error);
689 stq_be_p(buf + 8, reply->handle);
690
691 ret = write_sync(ioc, buf, sizeof(buf));
692 if (ret < 0) {
693 return ret;
694 }
695
696 if (ret != sizeof(buf)) {
697 LOG("writing to socket failed");
698 return -EINVAL;
699 }
700 return 0;
701 }
702
703 #define MAX_NBD_REQUESTS 16
704
705 void nbd_client_get(NBDClient *client)
706 {
707 client->refcount++;
708 }
709
710 void nbd_client_put(NBDClient *client)
711 {
712 if (--client->refcount == 0) {
713 /* The last reference should be dropped by client->close,
714 * which is called by client_close.
715 */
716 assert(client->closing);
717
718 nbd_unset_handlers(client);
719 object_unref(OBJECT(client->sioc));
720 object_unref(OBJECT(client->ioc));
721 if (client->tlscreds) {
722 object_unref(OBJECT(client->tlscreds));
723 }
724 g_free(client->tlsaclname);
725 if (client->exp) {
726 QTAILQ_REMOVE(&client->exp->clients, client, next);
727 nbd_export_put(client->exp);
728 }
729 g_free(client);
730 }
731 }
732
733 static void client_close(NBDClient *client)
734 {
735 if (client->closing) {
736 return;
737 }
738
739 client->closing = true;
740
741 /* Force requests to finish. They will drop their own references,
742 * then we'll close the socket and free the NBDClient.
743 */
744 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
745 NULL);
746
747 /* Also tell the client, so that they release their reference. */
748 if (client->close) {
749 client->close(client);
750 }
751 }
752
753 static NBDRequest *nbd_request_get(NBDClient *client)
754 {
755 NBDRequest *req;
756
757 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
758 client->nb_requests++;
759 nbd_update_can_read(client);
760
761 req = g_new0(NBDRequest, 1);
762 nbd_client_get(client);
763 req->client = client;
764 return req;
765 }
766
767 static void nbd_request_put(NBDRequest *req)
768 {
769 NBDClient *client = req->client;
770
771 if (req->data) {
772 qemu_vfree(req->data);
773 }
774 g_free(req);
775
776 client->nb_requests--;
777 nbd_update_can_read(client);
778 nbd_client_put(client);
779 }
780
781 static void blk_aio_attached(AioContext *ctx, void *opaque)
782 {
783 NBDExport *exp = opaque;
784 NBDClient *client;
785
786 TRACE("Export %s: Attaching clients to AIO context %p\n", exp->name, ctx);
787
788 exp->ctx = ctx;
789
790 QTAILQ_FOREACH(client, &exp->clients, next) {
791 nbd_set_handlers(client);
792 }
793 }
794
795 static void blk_aio_detach(void *opaque)
796 {
797 NBDExport *exp = opaque;
798 NBDClient *client;
799
800 TRACE("Export %s: Detaching clients from AIO context %p\n", exp->name, exp->ctx);
801
802 QTAILQ_FOREACH(client, &exp->clients, next) {
803 nbd_unset_handlers(client);
804 }
805
806 exp->ctx = NULL;
807 }
808
809 static void nbd_eject_notifier(Notifier *n, void *data)
810 {
811 NBDExport *exp = container_of(n, NBDExport, eject_notifier);
812 nbd_export_close(exp);
813 }
814
815 NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
816 uint32_t nbdflags, void (*close)(NBDExport *),
817 Error **errp)
818 {
819 NBDExport *exp = g_malloc0(sizeof(NBDExport));
820 exp->refcount = 1;
821 QTAILQ_INIT(&exp->clients);
822 exp->blk = blk;
823 exp->dev_offset = dev_offset;
824 exp->nbdflags = nbdflags;
825 exp->size = size < 0 ? blk_getlength(blk) : size;
826 if (exp->size < 0) {
827 error_setg_errno(errp, -exp->size,
828 "Failed to determine the NBD export's length");
829 goto fail;
830 }
831 exp->size -= exp->size % BDRV_SECTOR_SIZE;
832
833 exp->close = close;
834 exp->ctx = blk_get_aio_context(blk);
835 blk_ref(blk);
836 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
837
838 exp->eject_notifier.notify = nbd_eject_notifier;
839 blk_add_remove_bs_notifier(blk, &exp->eject_notifier);
840
841 /*
842 * NBD exports are used for non-shared storage migration. Make sure
843 * that BDRV_O_INACTIVE is cleared and the image is ready for write
844 * access since the export could be available before migration handover.
845 */
846 aio_context_acquire(exp->ctx);
847 blk_invalidate_cache(blk, NULL);
848 aio_context_release(exp->ctx);
849 return exp;
850
851 fail:
852 g_free(exp);
853 return NULL;
854 }
855
856 NBDExport *nbd_export_find(const char *name)
857 {
858 NBDExport *exp;
859 QTAILQ_FOREACH(exp, &exports, next) {
860 if (strcmp(name, exp->name) == 0) {
861 return exp;
862 }
863 }
864
865 return NULL;
866 }
867
868 void nbd_export_set_name(NBDExport *exp, const char *name)
869 {
870 if (exp->name == name) {
871 return;
872 }
873
874 nbd_export_get(exp);
875 if (exp->name != NULL) {
876 g_free(exp->name);
877 exp->name = NULL;
878 QTAILQ_REMOVE(&exports, exp, next);
879 nbd_export_put(exp);
880 }
881 if (name != NULL) {
882 nbd_export_get(exp);
883 exp->name = g_strdup(name);
884 QTAILQ_INSERT_TAIL(&exports, exp, next);
885 }
886 nbd_export_put(exp);
887 }
888
889 void nbd_export_close(NBDExport *exp)
890 {
891 NBDClient *client, *next;
892
893 nbd_export_get(exp);
894 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
895 client_close(client);
896 }
897 nbd_export_set_name(exp, NULL);
898 nbd_export_put(exp);
899 }
900
901 void nbd_export_get(NBDExport *exp)
902 {
903 assert(exp->refcount > 0);
904 exp->refcount++;
905 }
906
907 void nbd_export_put(NBDExport *exp)
908 {
909 assert(exp->refcount > 0);
910 if (exp->refcount == 1) {
911 nbd_export_close(exp);
912 }
913
914 if (--exp->refcount == 0) {
915 assert(exp->name == NULL);
916
917 if (exp->close) {
918 exp->close(exp);
919 }
920
921 if (exp->blk) {
922 notifier_remove(&exp->eject_notifier);
923 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
924 blk_aio_detach, exp);
925 blk_unref(exp->blk);
926 exp->blk = NULL;
927 }
928
929 g_free(exp);
930 }
931 }
932
933 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
934 {
935 return exp->blk;
936 }
937
938 void nbd_export_close_all(void)
939 {
940 NBDExport *exp, *next;
941
942 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
943 nbd_export_close(exp);
944 }
945 }
946
947 static ssize_t nbd_co_send_reply(NBDRequest *req, struct nbd_reply *reply,
948 int len)
949 {
950 NBDClient *client = req->client;
951 ssize_t rc, ret;
952
953 g_assert(qemu_in_coroutine());
954 qemu_co_mutex_lock(&client->send_lock);
955 client->send_coroutine = qemu_coroutine_self();
956 nbd_set_handlers(client);
957
958 if (!len) {
959 rc = nbd_send_reply(client->ioc, reply);
960 } else {
961 qio_channel_set_cork(client->ioc, true);
962 rc = nbd_send_reply(client->ioc, reply);
963 if (rc >= 0) {
964 ret = write_sync(client->ioc, req->data, len);
965 if (ret != len) {
966 rc = -EIO;
967 }
968 }
969 qio_channel_set_cork(client->ioc, false);
970 }
971
972 client->send_coroutine = NULL;
973 nbd_set_handlers(client);
974 qemu_co_mutex_unlock(&client->send_lock);
975 return rc;
976 }
977
978 static ssize_t nbd_co_receive_request(NBDRequest *req, struct nbd_request *request)
979 {
980 NBDClient *client = req->client;
981 uint32_t command;
982 ssize_t rc;
983
984 g_assert(qemu_in_coroutine());
985 client->recv_coroutine = qemu_coroutine_self();
986 nbd_update_can_read(client);
987
988 rc = nbd_receive_request(client->ioc, request);
989 if (rc < 0) {
990 if (rc != -EAGAIN) {
991 rc = -EIO;
992 }
993 goto out;
994 }
995
996 if ((request->from + request->len) < request->from) {
997 LOG("integer overflow detected! "
998 "you're probably being attacked");
999 rc = -EINVAL;
1000 goto out;
1001 }
1002
1003 TRACE("Decoding type");
1004
1005 command = request->type & NBD_CMD_MASK_COMMAND;
1006 if (command == NBD_CMD_READ || command == NBD_CMD_WRITE) {
1007 if (request->len > NBD_MAX_BUFFER_SIZE) {
1008 LOG("len (%" PRIu32" ) is larger than max len (%u)",
1009 request->len, NBD_MAX_BUFFER_SIZE);
1010 rc = -EINVAL;
1011 goto out;
1012 }
1013
1014 req->data = blk_try_blockalign(client->exp->blk, request->len);
1015 if (req->data == NULL) {
1016 rc = -ENOMEM;
1017 goto out;
1018 }
1019 }
1020 if (command == NBD_CMD_WRITE) {
1021 TRACE("Reading %" PRIu32 " byte(s)", request->len);
1022
1023 if (read_sync(client->ioc, req->data, request->len) != request->len) {
1024 LOG("reading from socket failed");
1025 rc = -EIO;
1026 goto out;
1027 }
1028 }
1029 rc = 0;
1030
1031 out:
1032 client->recv_coroutine = NULL;
1033 nbd_update_can_read(client);
1034
1035 return rc;
1036 }
1037
1038 static void nbd_trip(void *opaque)
1039 {
1040 NBDClient *client = opaque;
1041 NBDExport *exp = client->exp;
1042 NBDRequest *req;
1043 struct nbd_request request;
1044 struct nbd_reply reply;
1045 ssize_t ret;
1046 uint32_t command;
1047 int flags;
1048
1049 TRACE("Reading request.");
1050 if (client->closing) {
1051 return;
1052 }
1053
1054 req = nbd_request_get(client);
1055 ret = nbd_co_receive_request(req, &request);
1056 if (ret == -EAGAIN) {
1057 goto done;
1058 }
1059 if (ret == -EIO) {
1060 goto out;
1061 }
1062
1063 reply.handle = request.handle;
1064 reply.error = 0;
1065
1066 if (ret < 0) {
1067 reply.error = -ret;
1068 goto error_reply;
1069 }
1070 command = request.type & NBD_CMD_MASK_COMMAND;
1071 if (command != NBD_CMD_DISC && (request.from + request.len) > exp->size) {
1072 LOG("From: %" PRIu64 ", Len: %" PRIu32", Size: %" PRIu64
1073 ", Offset: %" PRIu64 "\n",
1074 request.from, request.len,
1075 (uint64_t)exp->size, (uint64_t)exp->dev_offset);
1076 LOG("requested operation past EOF--bad client?");
1077 goto invalid_request;
1078 }
1079
1080 if (client->closing) {
1081 /*
1082 * The client may be closed when we are blocked in
1083 * nbd_co_receive_request()
1084 */
1085 goto done;
1086 }
1087
1088 switch (command) {
1089 case NBD_CMD_READ:
1090 TRACE("Request type is READ");
1091
1092 if (request.type & NBD_CMD_FLAG_FUA) {
1093 ret = blk_co_flush(exp->blk);
1094 if (ret < 0) {
1095 LOG("flush failed");
1096 reply.error = -ret;
1097 goto error_reply;
1098 }
1099 }
1100
1101 ret = blk_pread(exp->blk, request.from + exp->dev_offset,
1102 req->data, request.len);
1103 if (ret < 0) {
1104 LOG("reading from file failed");
1105 reply.error = -ret;
1106 goto error_reply;
1107 }
1108
1109 TRACE("Read %" PRIu32" byte(s)", request.len);
1110 if (nbd_co_send_reply(req, &reply, request.len) < 0)
1111 goto out;
1112 break;
1113 case NBD_CMD_WRITE:
1114 TRACE("Request type is WRITE");
1115
1116 if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
1117 TRACE("Server is read-only, return error");
1118 reply.error = EROFS;
1119 goto error_reply;
1120 }
1121
1122 TRACE("Writing to device");
1123
1124 flags = 0;
1125 if (request.type & NBD_CMD_FLAG_FUA) {
1126 flags |= BDRV_REQ_FUA;
1127 }
1128 ret = blk_pwrite(exp->blk, request.from + exp->dev_offset,
1129 req->data, request.len, flags);
1130 if (ret < 0) {
1131 LOG("writing to file failed");
1132 reply.error = -ret;
1133 goto error_reply;
1134 }
1135
1136 if (nbd_co_send_reply(req, &reply, 0) < 0) {
1137 goto out;
1138 }
1139 break;
1140 case NBD_CMD_DISC:
1141 TRACE("Request type is DISCONNECT");
1142 errno = 0;
1143 goto out;
1144 case NBD_CMD_FLUSH:
1145 TRACE("Request type is FLUSH");
1146
1147 ret = blk_co_flush(exp->blk);
1148 if (ret < 0) {
1149 LOG("flush failed");
1150 reply.error = -ret;
1151 }
1152 if (nbd_co_send_reply(req, &reply, 0) < 0) {
1153 goto out;
1154 }
1155 break;
1156 case NBD_CMD_TRIM:
1157 TRACE("Request type is TRIM");
1158 /* Ignore unaligned head or tail, until block layer adds byte
1159 * interface */
1160 if (request.len >= BDRV_SECTOR_SIZE) {
1161 request.len -= (request.from + request.len) % BDRV_SECTOR_SIZE;
1162 ret = blk_co_discard(exp->blk,
1163 DIV_ROUND_UP(request.from + exp->dev_offset,
1164 BDRV_SECTOR_SIZE),
1165 request.len / BDRV_SECTOR_SIZE);
1166 if (ret < 0) {
1167 LOG("discard failed");
1168 reply.error = -ret;
1169 }
1170 } else {
1171 TRACE("trim request too small, ignoring");
1172 }
1173 if (nbd_co_send_reply(req, &reply, 0) < 0) {
1174 goto out;
1175 }
1176 break;
1177 default:
1178 LOG("invalid request type (%" PRIu32 ") received", request.type);
1179 invalid_request:
1180 reply.error = EINVAL;
1181 error_reply:
1182 if (nbd_co_send_reply(req, &reply, 0) < 0) {
1183 goto out;
1184 }
1185 break;
1186 }
1187
1188 TRACE("Request/Reply complete");
1189
1190 done:
1191 nbd_request_put(req);
1192 return;
1193
1194 out:
1195 nbd_request_put(req);
1196 client_close(client);
1197 }
1198
1199 static void nbd_read(void *opaque)
1200 {
1201 NBDClient *client = opaque;
1202
1203 if (client->recv_coroutine) {
1204 qemu_coroutine_enter(client->recv_coroutine, NULL);
1205 } else {
1206 qemu_coroutine_enter(qemu_coroutine_create(nbd_trip), client);
1207 }
1208 }
1209
1210 static void nbd_restart_write(void *opaque)
1211 {
1212 NBDClient *client = opaque;
1213
1214 qemu_coroutine_enter(client->send_coroutine, NULL);
1215 }
1216
1217 static void nbd_set_handlers(NBDClient *client)
1218 {
1219 if (client->exp && client->exp->ctx) {
1220 aio_set_fd_handler(client->exp->ctx, client->sioc->fd,
1221 true,
1222 client->can_read ? nbd_read : NULL,
1223 client->send_coroutine ? nbd_restart_write : NULL,
1224 client);
1225 }
1226 }
1227
1228 static void nbd_unset_handlers(NBDClient *client)
1229 {
1230 if (client->exp && client->exp->ctx) {
1231 aio_set_fd_handler(client->exp->ctx, client->sioc->fd,
1232 true, NULL, NULL, NULL);
1233 }
1234 }
1235
1236 static void nbd_update_can_read(NBDClient *client)
1237 {
1238 bool can_read = client->recv_coroutine ||
1239 client->nb_requests < MAX_NBD_REQUESTS;
1240
1241 if (can_read != client->can_read) {
1242 client->can_read = can_read;
1243 nbd_set_handlers(client);
1244
1245 /* There is no need to invoke aio_notify(), since aio_set_fd_handler()
1246 * in nbd_set_handlers() will have taken care of that */
1247 }
1248 }
1249
1250 static coroutine_fn void nbd_co_client_start(void *opaque)
1251 {
1252 NBDClientNewData *data = opaque;
1253 NBDClient *client = data->client;
1254 NBDExport *exp = client->exp;
1255
1256 if (exp) {
1257 nbd_export_get(exp);
1258 }
1259 if (nbd_negotiate(data)) {
1260 client_close(client);
1261 goto out;
1262 }
1263 qemu_co_mutex_init(&client->send_lock);
1264 nbd_set_handlers(client);
1265
1266 if (exp) {
1267 QTAILQ_INSERT_TAIL(&exp->clients, client, next);
1268 }
1269 out:
1270 g_free(data);
1271 }
1272
1273 void nbd_client_new(NBDExport *exp,
1274 QIOChannelSocket *sioc,
1275 QCryptoTLSCreds *tlscreds,
1276 const char *tlsaclname,
1277 void (*close_fn)(NBDClient *))
1278 {
1279 NBDClient *client;
1280 NBDClientNewData *data = g_new(NBDClientNewData, 1);
1281
1282 client = g_malloc0(sizeof(NBDClient));
1283 client->refcount = 1;
1284 client->exp = exp;
1285 client->tlscreds = tlscreds;
1286 if (tlscreds) {
1287 object_ref(OBJECT(client->tlscreds));
1288 }
1289 client->tlsaclname = g_strdup(tlsaclname);
1290 client->sioc = sioc;
1291 object_ref(OBJECT(client->sioc));
1292 client->ioc = QIO_CHANNEL(sioc);
1293 object_ref(OBJECT(client->ioc));
1294 client->can_read = true;
1295 client->close = close_fn;
1296
1297 data->client = client;
1298 data->co = qemu_coroutine_create(nbd_co_client_start);
1299 qemu_coroutine_enter(data->co, data);
1300 }