nbd.c

   1 /*
   2  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
   3  *
   4  *  Network Block Device
   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 "nbd.h"
  20 #include "block.h"
  21 #include "block_int.h"
  22
  23 #include "qemu-coroutine.h"
  24
  25 #include <errno.h>
  26 #include <string.h>
  27 #ifndef _WIN32
  28 #include <sys/ioctl.h>
  29 #endif
  30 #if defined(__sun__) || defined(__HAIKU__)
  31 #include <sys/ioccom.h>
  32 #endif
  33 #include <ctype.h>
  34 #include <inttypes.h>
  35
  36 #ifdef __linux__
  37 #include <linux/fs.h>
  38 #endif
  39
  40 #include "qemu_socket.h"
  41 #include "qemu-queue.h"
  42
  43 //#define DEBUG_NBD
  44
  45 #ifdef DEBUG_NBD
  46 #define TRACE(msg, ...) do { \
  47     LOG(msg, ## __VA_ARGS__); \
  48 } while(0)
  49 #else
  50 #define TRACE(msg, ...) \
  51     do { } while (0)
  52 #endif
  53
  54 #define LOG(msg, ...) do { \
  55     fprintf(stderr, "%s:%s():L%d: " msg "\n", \
  56             __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
  57 } while(0)
  58
  59 /* This is all part of the "official" NBD API */
  60
  61 #define NBD_REPLY_SIZE          (4 + 4 + 8)
  62 #define NBD_REQUEST_MAGIC       0x25609513
  63 #define NBD_REPLY_MAGIC         0x67446698
  64
  65 #define NBD_SET_SOCK            _IO(0xab, 0)
  66 #define NBD_SET_BLKSIZE         _IO(0xab, 1)
  67 #define NBD_SET_SIZE            _IO(0xab, 2)
  68 #define NBD_DO_IT               _IO(0xab, 3)
  69 #define NBD_CLEAR_SOCK          _IO(0xab, 4)
  70 #define NBD_CLEAR_QUE           _IO(0xab, 5)
  71 #define NBD_PRINT_DEBUG         _IO(0xab, 6)
  72 #define NBD_SET_SIZE_BLOCKS     _IO(0xab, 7)
  73 #define NBD_DISCONNECT          _IO(0xab, 8)
  74 #define NBD_SET_TIMEOUT         _IO(0xab, 9)
  75 #define NBD_SET_FLAGS           _IO(0xab, 10)
  76
  77 #define NBD_OPT_EXPORT_NAME     (1 << 0)
  78
  79 /* That's all folks */
  80
  81 #define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
  82 #define write_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, false)
  83
  84 size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
  85 {
  86     size_t offset = 0;
  87
  88     if (qemu_in_coroutine()) {
  89         if (do_read) {
  90             return qemu_co_recv(fd, buffer, size);
  91         } else {
  92             return qemu_co_send(fd, buffer, size);
  93         }
  94     }
  95
  96     while (offset < size) {
  97         ssize_t len;
  98
  99         if (do_read) {
 100             len = qemu_recv(fd, buffer + offset, size - offset, 0);
 101         } else {
 102             len = send(fd, buffer + offset, size - offset, 0);
 103         }
 104
 105         if (len < 0) {
 106             errno = socket_error();
 107
 108             /* recoverable error */
 109             if (errno == EINTR || errno == EAGAIN) {
 110                 continue;
 111             }
 112
 113             /* unrecoverable error */
 114             return 0;
 115         }
 116
 117         /* eof */
 118         if (len == 0) {
 119             break;
 120         }
 121
 122         offset += len;
 123     }
 124
 125     return offset;
 126 }
 127
 128 static void combine_addr(char *buf, size_t len, const char* address,
 129                          uint16_t port)
 130 {
 131     /* If the address-part contains a colon, it's an IPv6 IP so needs [] */
 132     if (strstr(address, ":")) {
 133         snprintf(buf, len, "[%s]:%u", address, port);
 134     } else {
 135         snprintf(buf, len, "%s:%u", address, port);
 136     }
 137 }
 138
 139 int tcp_socket_outgoing(const char *address, uint16_t port)
 140 {
 141     char address_and_port[128];
 142     combine_addr(address_and_port, 128, address, port);
 143     return tcp_socket_outgoing_spec(address_and_port);
 144 }
 145
 146 int tcp_socket_outgoing_spec(const char *address_and_port)
 147 {
 148     return inet_connect(address_and_port, SOCK_STREAM);
 149 }
 150
 151 int tcp_socket_incoming(const char *address, uint16_t port)
 152 {
 153     char address_and_port[128];
 154     combine_addr(address_and_port, 128, address, port);
 155     return tcp_socket_incoming_spec(address_and_port);
 156 }
 157
 158 int tcp_socket_incoming_spec(const char *address_and_port)
 159 {
 160     char *ostr  = NULL;
 161     int olen = 0;
 162     return inet_listen(address_and_port, ostr, olen, SOCK_STREAM, 0);
 163 }
 164
 165 int unix_socket_incoming(const char *path)
 166 {
 167     char *ostr = NULL;
 168     int olen = 0;
 169
 170     return unix_listen(path, ostr, olen);
 171 }
 172
 173 int unix_socket_outgoing(const char *path)
 174 {
 175     return unix_connect(path);
 176 }
 177
 178 /* Basic flow
 179
 180    Server         Client
 181
 182    Negotiate
 183                   Request
 184    Response
 185                   Request
 186    Response
 187                   ...
 188    ...
 189                   Request (type == 2)
 190 */
 191
 192 static int nbd_send_negotiate(int csock, off_t size, uint32_t flags)
 193 {
 194     char buf[8 + 8 + 8 + 128];
 195
 196     /* Negotiate
 197         [ 0 ..   7]   passwd   ("NBDMAGIC")
 198         [ 8 ..  15]   magic    (0x00420281861253)
 199         [16 ..  23]   size
 200         [24 ..  27]   flags
 201         [28 .. 151]   reserved (0)
 202      */
 203
 204     TRACE("Beginning negotiation.");
 205     memcpy(buf, "NBDMAGIC", 8);
 206     cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL);
 207     cpu_to_be64w((uint64_t*)(buf + 16), size);
 208     cpu_to_be32w((uint32_t*)(buf + 24),
 209                  flags | NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
 210                  NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA);
 211     memset(buf + 28, 0, 124);
 212
 213     if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 214         LOG("write failed");
 215         errno = EINVAL;
 216         return -1;
 217     }
 218
 219     TRACE("Negotiation succeeded.");
 220
 221     return 0;
 222 }
 223
 224 int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
 225                           off_t *size, size_t *blocksize)
 226 {
 227     char buf[256];
 228     uint64_t magic, s;
 229     uint16_t tmp;
 230
 231     TRACE("Receiving negotiation.");
 232
 233     if (read_sync(csock, buf, 8) != 8) {
 234         LOG("read failed");
 235         errno = EINVAL;
 236         return -1;
 237     }
 238
 239     buf[8] = '\0';
 240     if (strlen(buf) == 0) {
 241         LOG("server connection closed");
 242         errno = EINVAL;
 243         return -1;
 244     }
 245
 246     TRACE("Magic is %c%c%c%c%c%c%c%c",
 247           qemu_isprint(buf[0]) ? buf[0] : '.',
 248           qemu_isprint(buf[1]) ? buf[1] : '.',
 249           qemu_isprint(buf[2]) ? buf[2] : '.',
 250           qemu_isprint(buf[3]) ? buf[3] : '.',
 251           qemu_isprint(buf[4]) ? buf[4] : '.',
 252           qemu_isprint(buf[5]) ? buf[5] : '.',
 253           qemu_isprint(buf[6]) ? buf[6] : '.',
 254           qemu_isprint(buf[7]) ? buf[7] : '.');
 255
 256     if (memcmp(buf, "NBDMAGIC", 8) != 0) {
 257         LOG("Invalid magic received");
 258         errno = EINVAL;
 259         return -1;
 260     }
 261
 262     if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
 263         LOG("read failed");
 264         errno = EINVAL;
 265         return -1;
 266     }
 267     magic = be64_to_cpu(magic);
 268     TRACE("Magic is 0x%" PRIx64, magic);
 269
 270     if (name) {
 271         uint32_t reserved = 0;
 272         uint32_t opt;
 273         uint32_t namesize;
 274
 275         TRACE("Checking magic (opts_magic)");
 276         if (magic != 0x49484156454F5054LL) {
 277             LOG("Bad magic received");
 278             errno = EINVAL;
 279             return -1;
 280         }
 281         if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
 282             LOG("flags read failed");
 283             errno = EINVAL;
 284             return -1;
 285         }
 286         *flags = be16_to_cpu(tmp) << 16;
 287         /* reserved for future use */
 288         if (write_sync(csock, &reserved, sizeof(reserved)) !=
 289             sizeof(reserved)) {
 290             LOG("write failed (reserved)");
 291             errno = EINVAL;
 292             return -1;
 293         }
 294         /* write the export name */
 295         magic = cpu_to_be64(magic);
 296         if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
 297             LOG("write failed (magic)");
 298             errno = EINVAL;
 299             return -1;
 300         }
 301         opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
 302         if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
 303             LOG("write failed (opt)");
 304             errno = EINVAL;
 305             return -1;
 306         }
 307         namesize = cpu_to_be32(strlen(name));
 308         if (write_sync(csock, &namesize, sizeof(namesize)) !=
 309             sizeof(namesize)) {
 310             LOG("write failed (namesize)");
 311             errno = EINVAL;
 312             return -1;
 313         }
 314         if (write_sync(csock, (char*)name, strlen(name)) != strlen(name)) {
 315             LOG("write failed (name)");
 316             errno = EINVAL;
 317             return -1;
 318         }
 319     } else {
 320         TRACE("Checking magic (cli_magic)");
 321
 322         if (magic != 0x00420281861253LL) {
 323             LOG("Bad magic received");
 324             errno = EINVAL;
 325             return -1;
 326         }
 327     }
 328
 329     if (read_sync(csock, &s, sizeof(s)) != sizeof(s)) {
 330         LOG("read failed");
 331         errno = EINVAL;
 332         return -1;
 333     }
 334     *size = be64_to_cpu(s);
 335     *blocksize = 1024;
 336     TRACE("Size is %" PRIu64, *size);
 337
 338     if (!name) {
 339         if (read_sync(csock, flags, sizeof(*flags)) != sizeof(*flags)) {
 340             LOG("read failed (flags)");
 341             errno = EINVAL;
 342             return -1;
 343         }
 344         *flags = be32_to_cpup(flags);
 345     } else {
 346         if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
 347             LOG("read failed (tmp)");
 348             errno = EINVAL;
 349             return -1;
 350         }
 351         *flags |= be32_to_cpu(tmp);
 352     }
 353     if (read_sync(csock, &buf, 124) != 124) {
 354         LOG("read failed (buf)");
 355         errno = EINVAL;
 356         return -1;
 357     }
 358         return 0;
 359 }
 360
 361 #ifdef __linux__
 362 int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
 363 {
 364     TRACE("Setting NBD socket");
 365
 366     if (ioctl(fd, NBD_SET_SOCK, csock) < 0) {
 367         int serrno = errno;
 368         LOG("Failed to set NBD socket");
 369         errno = serrno;
 370         return -1;
 371     }
 372
 373     TRACE("Setting block size to %lu", (unsigned long)blocksize);
 374
 375     if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) < 0) {
 376         int serrno = errno;
 377         LOG("Failed setting NBD block size");
 378         errno = serrno;
 379         return -1;
 380     }
 381
 382         TRACE("Setting size to %zd block(s)", (size_t)(size / blocksize));
 383
 384     if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) < 0) {
 385         int serrno = errno;
 386         LOG("Failed setting size (in blocks)");
 387         errno = serrno;
 388         return -1;
 389     }
 390
 391     if (flags & NBD_FLAG_READ_ONLY) {
 392         int read_only = 1;
 393         TRACE("Setting readonly attribute");
 394
 395         if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
 396             int serrno = errno;
 397             LOG("Failed setting read-only attribute");
 398             errno = serrno;
 399             return -1;
 400         }
 401     }
 402
 403     if (ioctl(fd, NBD_SET_FLAGS, flags) < 0
 404         && errno != ENOTTY) {
 405         int serrno = errno;
 406         LOG("Failed setting flags");
 407         errno = serrno;
 408         return -1;
 409     }
 410
 411     TRACE("Negotiation ended");
 412
 413     return 0;
 414 }
 415
 416 int nbd_disconnect(int fd)
 417 {
 418     ioctl(fd, NBD_CLEAR_QUE);
 419     ioctl(fd, NBD_DISCONNECT);
 420     ioctl(fd, NBD_CLEAR_SOCK);
 421     return 0;
 422 }
 423
 424 int nbd_client(int fd)
 425 {
 426     int ret;
 427     int serrno;
 428
 429     TRACE("Doing NBD loop");
 430
 431     ret = ioctl(fd, NBD_DO_IT);
 432     if (ret < 0 && errno == EPIPE) {
 433         /* NBD_DO_IT normally returns EPIPE when someone has disconnected
 434          * the socket via NBD_DISCONNECT.  We do not want to return 1 in
 435          * that case.
 436          */
 437         ret = 0;
 438     }
 439     serrno = errno;
 440
 441     TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
 442
 443     TRACE("Clearing NBD queue");
 444     ioctl(fd, NBD_CLEAR_QUE);
 445
 446     TRACE("Clearing NBD socket");
 447     ioctl(fd, NBD_CLEAR_SOCK);
 448
 449     errno = serrno;
 450     return ret;
 451 }
 452 #else
 453 int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
 454 {
 455     errno = ENOTSUP;
 456     return -1;
 457 }
 458
 459 int nbd_disconnect(int fd)
 460 {
 461     errno = ENOTSUP;
 462     return -1;
 463 }
 464
 465 int nbd_client(int fd)
 466 {
 467     errno = ENOTSUP;
 468     return -1;
 469 }
 470 #endif
 471
 472 ssize_t nbd_send_request(int csock, struct nbd_request *request)
 473 {
 474     uint8_t buf[4 + 4 + 8 + 8 + 4];
 475
 476     cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
 477     cpu_to_be32w((uint32_t*)(buf + 4), request->type);
 478     cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
 479     cpu_to_be64w((uint64_t*)(buf + 16), request->from);
 480     cpu_to_be32w((uint32_t*)(buf + 24), request->len);
 481
 482     TRACE("Sending request to client: "
 483           "{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}",
 484           request->from, request->len, request->handle, request->type);
 485
 486     if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 487         LOG("writing to socket failed");
 488         errno = EINVAL;
 489         return -1;
 490     }
 491     return 0;
 492 }
 493
 494 static ssize_t nbd_receive_request(int csock, struct nbd_request *request)
 495 {
 496     uint8_t buf[4 + 4 + 8 + 8 + 4];
 497     uint32_t magic;
 498
 499     if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 500         LOG("read failed");
 501         errno = EINVAL;
 502         return -1;
 503     }
 504
 505     /* Request
 506        [ 0 ..  3]   magic   (NBD_REQUEST_MAGIC)
 507        [ 4 ..  7]   type    (0 == READ, 1 == WRITE)
 508        [ 8 .. 15]   handle
 509        [16 .. 23]   from
 510        [24 .. 27]   len
 511      */
 512
 513     magic = be32_to_cpup((uint32_t*)buf);
 514     request->type  = be32_to_cpup((uint32_t*)(buf + 4));
 515     request->handle = be64_to_cpup((uint64_t*)(buf + 8));
 516     request->from  = be64_to_cpup((uint64_t*)(buf + 16));
 517     request->len   = be32_to_cpup((uint32_t*)(buf + 24));
 518
 519     TRACE("Got request: "
 520           "{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
 521           magic, request->type, request->from, request->len);
 522
 523     if (magic != NBD_REQUEST_MAGIC) {
 524         LOG("invalid magic (got 0x%x)", magic);
 525         errno = EINVAL;
 526         return -1;
 527     }
 528     return 0;
 529 }
 530
 531 ssize_t nbd_receive_reply(int csock, struct nbd_reply *reply)
 532 {
 533     uint8_t buf[NBD_REPLY_SIZE];
 534     uint32_t magic;
 535
 536     if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 537         LOG("read failed");
 538         errno = EINVAL;
 539         return -1;
 540     }
 541
 542     /* Reply
 543        [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
 544        [ 4 ..  7]    error   (0 == no error)
 545        [ 7 .. 15]    handle
 546      */
 547
 548     magic = be32_to_cpup((uint32_t*)buf);
 549     reply->error  = be32_to_cpup((uint32_t*)(buf + 4));
 550     reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
 551
 552     TRACE("Got reply: "
 553           "{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
 554           magic, reply->error, reply->handle);
 555
 556     if (magic != NBD_REPLY_MAGIC) {
 557         LOG("invalid magic (got 0x%x)", magic);
 558         errno = EINVAL;
 559         return -1;
 560     }
 561     return 0;
 562 }
 563
 564 static ssize_t nbd_send_reply(int csock, struct nbd_reply *reply)
 565 {
 566     uint8_t buf[4 + 4 + 8];
 567
 568     /* Reply
 569        [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
 570        [ 4 ..  7]    error   (0 == no error)
 571        [ 7 .. 15]    handle
 572      */
 573     cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
 574     cpu_to_be32w((uint32_t*)(buf + 4), reply->error);
 575     cpu_to_be64w((uint64_t*)(buf + 8), reply->handle);
 576
 577     TRACE("Sending response to client");
 578
 579     if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 580         LOG("writing to socket failed");
 581         errno = EINVAL;
 582         return -1;
 583     }
 584     return 0;
 585 }
 586
 587 #define MAX_NBD_REQUESTS 16
 588
 589 typedef struct NBDRequest NBDRequest;
 590
 591 struct NBDRequest {
 592     QSIMPLEQ_ENTRY(NBDRequest) entry;
 593     NBDClient *client;
 594     uint8_t *data;
 595 };
 596
 597 struct NBDExport {
 598     BlockDriverState *bs;
 599     off_t dev_offset;
 600     off_t size;
 601     uint32_t nbdflags;
 602     QSIMPLEQ_HEAD(, NBDRequest) requests;
 603 };
 604
 605 struct NBDClient {
 606     int refcount;
 607     void (*close)(NBDClient *client);
 608
 609     NBDExport *exp;
 610     int sock;
 611
 612     Coroutine *recv_coroutine;
 613
 614     CoMutex send_lock;
 615     Coroutine *send_coroutine;
 616
 617     int nb_requests;
 618 };
 619
 620 static void nbd_client_get(NBDClient *client)
 621 {
 622     client->refcount++;
 623 }
 624
 625 static void nbd_client_put(NBDClient *client)
 626 {
 627     if (--client->refcount == 0) {
 628         g_free(client);
 629     }
 630 }
 631
 632 static void nbd_client_close(NBDClient *client)
 633 {
 634     qemu_set_fd_handler2(client->sock, NULL, NULL, NULL, NULL);
 635     close(client->sock);
 636     client->sock = -1;
 637     if (client->close) {
 638         client->close(client);
 639     }
 640     nbd_client_put(client);
 641 }
 642
 643 static NBDRequest *nbd_request_get(NBDClient *client)
 644 {
 645     NBDRequest *req;
 646     NBDExport *exp = client->exp;
 647
 648     assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
 649     client->nb_requests++;
 650
 651     if (QSIMPLEQ_EMPTY(&exp->requests)) {
 652         req = g_malloc0(sizeof(NBDRequest));
 653         req->data = qemu_blockalign(exp->bs, NBD_BUFFER_SIZE);
 654     } else {
 655         req = QSIMPLEQ_FIRST(&exp->requests);
 656         QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry);
 657     }
 658     nbd_client_get(client);
 659     req->client = client;
 660     return req;
 661 }
 662
 663 static void nbd_request_put(NBDRequest *req)
 664 {
 665     NBDClient *client = req->client;
 666     QSIMPLEQ_INSERT_HEAD(&client->exp->requests, req, entry);
 667     if (client->nb_requests-- == MAX_NBD_REQUESTS) {
 668         qemu_notify_event();
 669     }
 670     nbd_client_put(client);
 671 }
 672
 673 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset,
 674                           off_t size, uint32_t nbdflags)
 675 {
 676     NBDExport *exp = g_malloc0(sizeof(NBDExport));
 677     QSIMPLEQ_INIT(&exp->requests);
 678     exp->bs = bs;
 679     exp->dev_offset = dev_offset;
 680     exp->nbdflags = nbdflags;
 681     exp->size = size == -1 ? exp->bs->total_sectors * 512 : size;
 682     return exp;
 683 }
 684
 685 void nbd_export_close(NBDExport *exp)
 686 {
 687     while (!QSIMPLEQ_EMPTY(&exp->requests)) {
 688         NBDRequest *first = QSIMPLEQ_FIRST(&exp->requests);
 689         QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry);
 690         qemu_vfree(first->data);
 691         g_free(first);
 692     }
 693
 694     bdrv_close(exp->bs);
 695     g_free(exp);
 696 }
 697
 698 static int nbd_can_read(void *opaque);
 699 static void nbd_read(void *opaque);
 700 static void nbd_restart_write(void *opaque);
 701
 702 static ssize_t nbd_co_send_reply(NBDRequest *req, struct nbd_reply *reply,
 703                                  int len)
 704 {
 705     NBDClient *client = req->client;
 706     int csock = client->sock;
 707     ssize_t rc, ret;
 708
 709     qemu_co_mutex_lock(&client->send_lock);
 710     qemu_set_fd_handler2(csock, nbd_can_read, nbd_read,
 711                          nbd_restart_write, client);
 712     client->send_coroutine = qemu_coroutine_self();
 713
 714     if (!len) {
 715         rc = nbd_send_reply(csock, reply);
 716         if (rc < 0) {
 717             rc = -errno;
 718         }
 719     } else {
 720         socket_set_cork(csock, 1);
 721         rc = nbd_send_reply(csock, reply);
 722         if (rc >= 0) {
 723             ret = qemu_co_send(csock, req->data, len);
 724             if (ret != len) {
 725                 errno = EIO;
 726                 rc = -1;
 727             }
 728         }
 729         if (rc < 0) {
 730             rc = -errno;
 731         }
 732         socket_set_cork(csock, 0);
 733     }
 734
 735     client->send_coroutine = NULL;
 736     qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, NULL, client);
 737     qemu_co_mutex_unlock(&client->send_lock);
 738     return rc;
 739 }
 740
 741 static ssize_t nbd_co_receive_request(NBDRequest *req, struct nbd_request *request)
 742 {
 743     NBDClient *client = req->client;
 744     int csock = client->sock;
 745     ssize_t rc;
 746
 747     client->recv_coroutine = qemu_coroutine_self();
 748     if (nbd_receive_request(csock, request) < 0) {
 749         rc = -EIO;
 750         goto out;
 751     }
 752
 753     if (request->len > NBD_BUFFER_SIZE) {
 754         LOG("len (%u) is larger than max len (%u)",
 755             request->len, NBD_BUFFER_SIZE);
 756         rc = -EINVAL;
 757         goto out;
 758     }
 759
 760     if ((request->from + request->len) < request->from) {
 761         LOG("integer overflow detected! "
 762             "you're probably being attacked");
 763         rc = -EINVAL;
 764         goto out;
 765     }
 766
 767     TRACE("Decoding type");
 768
 769     if ((request->type & NBD_CMD_MASK_COMMAND) == NBD_CMD_WRITE) {
 770         TRACE("Reading %u byte(s)", request->len);
 771
 772         if (qemu_co_recv(csock, req->data, request->len) != request->len) {
 773             LOG("reading from socket failed");
 774             rc = -EIO;
 775             goto out;
 776         }
 777     }
 778     rc = 0;
 779
 780 out:
 781     client->recv_coroutine = NULL;
 782     return rc;
 783 }
 784
 785 static void nbd_trip(void *opaque)
 786 {
 787     NBDClient *client = opaque;
 788     NBDRequest *req = nbd_request_get(client);
 789     NBDExport *exp = client->exp;
 790     struct nbd_request request;
 791     struct nbd_reply reply;
 792     ssize_t ret;
 793
 794     TRACE("Reading request.");
 795
 796     ret = nbd_co_receive_request(req, &request);
 797     if (ret == -EIO) {
 798         goto out;
 799     }
 800
 801     reply.handle = request.handle;
 802     reply.error = 0;
 803
 804     if (ret < 0) {
 805         reply.error = -ret;
 806         goto error_reply;
 807     }
 808
 809     if ((request.from + request.len) > exp->size) {
 810             LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
 811             ", Offset: %" PRIu64 "\n",
 812                     request.from, request.len,
 813                     (uint64_t)exp->size, (uint64_t)exp->dev_offset);
 814         LOG("requested operation past EOF--bad client?");
 815         goto invalid_request;
 816     }
 817
 818     switch (request.type & NBD_CMD_MASK_COMMAND) {
 819     case NBD_CMD_READ:
 820         TRACE("Request type is READ");
 821
 822         ret = bdrv_read(exp->bs, (request.from + exp->dev_offset) / 512,
 823                         req->data, request.len / 512);
 824         if (ret < 0) {
 825             LOG("reading from file failed");
 826             reply.error = -ret;
 827             goto error_reply;
 828         }
 829
 830         TRACE("Read %u byte(s)", request.len);
 831         if (nbd_co_send_reply(req, &reply, request.len) < 0)
 832             goto out;
 833         break;
 834     case NBD_CMD_WRITE:
 835         TRACE("Request type is WRITE");
 836
 837         if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
 838             TRACE("Server is read-only, return error");
 839             reply.error = EROFS;
 840             goto error_reply;
 841         }
 842
 843         TRACE("Writing to device");
 844
 845         ret = bdrv_write(exp->bs, (request.from + exp->dev_offset) / 512,
 846                          req->data, request.len / 512);
 847         if (ret < 0) {
 848             LOG("writing to file failed");
 849             reply.error = -ret;
 850             goto error_reply;
 851         }
 852
 853         if (request.type & NBD_CMD_FLAG_FUA) {
 854             ret = bdrv_co_flush(exp->bs);
 855             if (ret < 0) {
 856                 LOG("flush failed");
 857                 reply.error = -ret;
 858                 goto error_reply;
 859             }
 860         }
 861
 862         if (nbd_co_send_reply(req, &reply, 0) < 0) {
 863             goto out;
 864         }
 865         break;
 866     case NBD_CMD_DISC:
 867         TRACE("Request type is DISCONNECT");
 868         errno = 0;
 869         goto out;
 870     case NBD_CMD_FLUSH:
 871         TRACE("Request type is FLUSH");
 872
 873         ret = bdrv_co_flush(exp->bs);
 874         if (ret < 0) {
 875             LOG("flush failed");
 876             reply.error = -ret;
 877         }
 878         if (nbd_co_send_reply(req, &reply, 0) < 0) {
 879             goto out;
 880         }
 881         break;
 882     case NBD_CMD_TRIM:
 883         TRACE("Request type is TRIM");
 884         ret = bdrv_co_discard(exp->bs, (request.from + exp->dev_offset) / 512,
 885                               request.len / 512);
 886         if (ret < 0) {
 887             LOG("discard failed");
 888             reply.error = -ret;
 889         }
 890         if (nbd_co_send_reply(req, &reply, 0) < 0) {
 891             goto out;
 892         }
 893         break;
 894     default:
 895         LOG("invalid request type (%u) received", request.type);
 896     invalid_request:
 897         reply.error = -EINVAL;
 898     error_reply:
 899         if (nbd_co_send_reply(req, &reply, 0) < 0) {
 900             goto out;
 901         }
 902         break;
 903     }
 904
 905     TRACE("Request/Reply complete");
 906
 907     nbd_request_put(req);
 908     return;
 909
 910 out:
 911     nbd_request_put(req);
 912     nbd_client_close(client);
 913 }
 914
 915 static int nbd_can_read(void *opaque)
 916 {
 917     NBDClient *client = opaque;
 918
 919     return client->recv_coroutine || client->nb_requests < MAX_NBD_REQUESTS;
 920 }
 921
 922 static void nbd_read(void *opaque)
 923 {
 924     NBDClient *client = opaque;
 925
 926     if (client->recv_coroutine) {
 927         qemu_coroutine_enter(client->recv_coroutine, NULL);
 928     } else {
 929         qemu_coroutine_enter(qemu_coroutine_create(nbd_trip), client);
 930     }
 931 }
 932
 933 static void nbd_restart_write(void *opaque)
 934 {
 935     NBDClient *client = opaque;
 936
 937     qemu_coroutine_enter(client->send_coroutine, NULL);
 938 }
 939
 940 NBDClient *nbd_client_new(NBDExport *exp, int csock,
 941                           void (*close)(NBDClient *))
 942 {
 943     NBDClient *client;
 944     if (nbd_send_negotiate(csock, exp->size, exp->nbdflags) < 0) {
 945         return NULL;
 946     }
 947     client = g_malloc0(sizeof(NBDClient));
 948     client->refcount = 1;
 949     client->exp = exp;
 950     client->sock = csock;
 951     client->close = close;
 952     qemu_co_mutex_init(&client->send_lock);
 953     qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, NULL, client);
 954     return client;
 955 }