symbian-qemu-0.9.1-12/qemu-symbian-svp/nbd.c
changeset 1 2fb8b9db1c86
equal deleted inserted replaced
0:ffa851df0825 1:2fb8b9db1c86
       
     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, write to the Free Software
       
    17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
       
    18  */
       
    19 
       
    20 #include "nbd.h"
       
    21 
       
    22 #include <errno.h>
       
    23 #include <string.h>
       
    24 #ifndef _WIN32
       
    25 #include <sys/ioctl.h>
       
    26 #endif
       
    27 #ifdef __sun__
       
    28 #include <sys/ioccom.h>
       
    29 #endif
       
    30 #include <ctype.h>
       
    31 #include <inttypes.h>
       
    32 
       
    33 #include "qemu_socket.h"
       
    34 
       
    35 //#define DEBUG_NBD
       
    36 
       
    37 #ifdef DEBUG_NBD
       
    38 #define TRACE(msg, ...) do { \
       
    39     LOG(msg, ## __VA_ARGS__); \
       
    40 } while(0)
       
    41 #else
       
    42 #define TRACE(msg, ...) \
       
    43     do { } while (0)
       
    44 #endif
       
    45 
       
    46 #define LOG(msg, ...) do { \
       
    47     fprintf(stderr, "%s:%s():L%d: " msg "\n", \
       
    48             __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
       
    49 } while(0)
       
    50 
       
    51 /* This is all part of the "official" NBD API */
       
    52 
       
    53 #define NBD_REQUEST_MAGIC       0x25609513
       
    54 #define NBD_REPLY_MAGIC         0x67446698
       
    55 
       
    56 #define NBD_SET_SOCK            _IO(0xab, 0)
       
    57 #define NBD_SET_BLKSIZE         _IO(0xab, 1)
       
    58 #define NBD_SET_SIZE            _IO(0xab, 2)
       
    59 #define NBD_DO_IT               _IO(0xab, 3)
       
    60 #define NBD_CLEAR_SOCK          _IO(0xab, 4)
       
    61 #define NBD_CLEAR_QUE           _IO(0xab, 5)
       
    62 #define NBD_PRINT_DEBUG	        _IO(0xab, 6)
       
    63 #define NBD_SET_SIZE_BLOCKS	_IO(0xab, 7)
       
    64 #define NBD_DISCONNECT          _IO(0xab, 8)
       
    65 
       
    66 /* That's all folks */
       
    67 
       
    68 #define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
       
    69 #define write_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, false)
       
    70 
       
    71 size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
       
    72 {
       
    73     size_t offset = 0;
       
    74 
       
    75     while (offset < size) {
       
    76         ssize_t len;
       
    77 
       
    78         if (do_read) {
       
    79             len = recv(fd, buffer + offset, size - offset, 0);
       
    80         } else {
       
    81             len = send(fd, buffer + offset, size - offset, 0);
       
    82         }
       
    83 
       
    84         if (len == -1)
       
    85             errno = socket_error();
       
    86 
       
    87         /* recoverable error */
       
    88         if (len == -1 && (errno == EAGAIN || errno == EINTR)) {
       
    89             continue;
       
    90         }
       
    91 
       
    92         /* eof */
       
    93         if (len == 0) {
       
    94             break;
       
    95         }
       
    96 
       
    97         /* unrecoverable error */
       
    98         if (len == -1) {
       
    99             return 0;
       
   100         }
       
   101 
       
   102         offset += len;
       
   103     }
       
   104 
       
   105     return offset;
       
   106 }
       
   107 
       
   108 int tcp_socket_outgoing(const char *address, uint16_t port)
       
   109 {
       
   110     int s;
       
   111     struct in_addr in;
       
   112     struct sockaddr_in addr;
       
   113 
       
   114     s = socket(PF_INET, SOCK_STREAM, 0);
       
   115     if (s == -1) {
       
   116         return -1;
       
   117     }
       
   118 
       
   119     if (inet_aton(address, &in) == 0) {
       
   120         struct hostent *ent;
       
   121 
       
   122         ent = gethostbyname(address);
       
   123         if (ent == NULL) {
       
   124             goto error;
       
   125         }
       
   126 
       
   127         memcpy(&in, ent->h_addr, sizeof(in));
       
   128     }
       
   129 
       
   130     addr.sin_family = AF_INET;
       
   131     addr.sin_port = htons(port);
       
   132     memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
       
   133 
       
   134     if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
       
   135         goto error;
       
   136     }
       
   137 
       
   138     return s;
       
   139 error:
       
   140     closesocket(s);
       
   141     return -1;
       
   142 }
       
   143 
       
   144 int tcp_socket_incoming(const char *address, uint16_t port)
       
   145 {
       
   146     int s;
       
   147     struct in_addr in;
       
   148     struct sockaddr_in addr;
       
   149     int opt;
       
   150 
       
   151     s = socket(PF_INET, SOCK_STREAM, 0);
       
   152     if (s == -1) {
       
   153         return -1;
       
   154     }
       
   155 
       
   156     if (inet_aton(address, &in) == 0) {
       
   157         struct hostent *ent;
       
   158 
       
   159         ent = gethostbyname(address);
       
   160         if (ent == NULL) {
       
   161             goto error;
       
   162         }
       
   163 
       
   164         memcpy(&in, ent->h_addr, sizeof(in));
       
   165     }
       
   166 
       
   167     addr.sin_family = AF_INET;
       
   168     addr.sin_port = htons(port);
       
   169     memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
       
   170 
       
   171     opt = 1;
       
   172     if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) == -1) {
       
   173         goto error;
       
   174     }
       
   175 
       
   176     if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
       
   177         goto error;
       
   178     }
       
   179 
       
   180     if (listen(s, 128) == -1) {
       
   181         goto error;
       
   182     }
       
   183 
       
   184     return s;
       
   185 error:
       
   186     closesocket(s);
       
   187     return -1;
       
   188 }
       
   189 
       
   190 #ifndef _WIN32
       
   191 int unix_socket_incoming(const char *path)
       
   192 {
       
   193     int s;
       
   194     struct sockaddr_un addr;
       
   195 
       
   196     s = socket(PF_UNIX, SOCK_STREAM, 0);
       
   197     if (s == -1) {
       
   198         return -1;
       
   199     }
       
   200 
       
   201     memset(&addr, 0, sizeof(addr));
       
   202     addr.sun_family = AF_UNIX;
       
   203     pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
       
   204 
       
   205     if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
       
   206         goto error;
       
   207     }
       
   208 
       
   209     if (listen(s, 128) == -1) {
       
   210         goto error;
       
   211     }
       
   212 
       
   213     return s;
       
   214 error:
       
   215     closesocket(s);
       
   216     return -1;
       
   217 }
       
   218 
       
   219 int unix_socket_outgoing(const char *path)
       
   220 {
       
   221     int s;
       
   222     struct sockaddr_un addr;
       
   223 
       
   224     s = socket(PF_UNIX, SOCK_STREAM, 0);
       
   225     if (s == -1) {
       
   226         return -1;
       
   227     }
       
   228 
       
   229     memset(&addr, 0, sizeof(addr));
       
   230     addr.sun_family = AF_UNIX;
       
   231     pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
       
   232 
       
   233     if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
       
   234         goto error;
       
   235     }
       
   236 
       
   237     return s;
       
   238 error:
       
   239     closesocket(s);
       
   240     return -1;
       
   241 }
       
   242 #else
       
   243 int unix_socket_incoming(const char *path)
       
   244 {
       
   245     errno = ENOTSUP;
       
   246     return -1;
       
   247 }
       
   248 
       
   249 int unix_socket_outgoing(const char *path)
       
   250 {
       
   251     errno = ENOTSUP;
       
   252     return -1;
       
   253 }
       
   254 #endif
       
   255 
       
   256 
       
   257 /* Basic flow
       
   258 
       
   259    Server         Client
       
   260 
       
   261    Negotiate
       
   262                   Request
       
   263    Response
       
   264                   Request
       
   265    Response
       
   266                   ...
       
   267    ...
       
   268                   Request (type == 2)
       
   269 */
       
   270 
       
   271 int nbd_negotiate(int csock, off_t size)
       
   272 {
       
   273 	char buf[8 + 8 + 8 + 128];
       
   274 
       
   275 	/* Negotiate
       
   276 	   [ 0 ..   7]   passwd   ("NBDMAGIC")
       
   277 	   [ 8 ..  15]   magic    (0x00420281861253)
       
   278 	   [16 ..  23]   size
       
   279 	   [24 .. 151]   reserved (0)
       
   280 	 */
       
   281 
       
   282 	TRACE("Beginning negotiation.");
       
   283 	memcpy(buf, "NBDMAGIC", 8);
       
   284 	cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL);
       
   285 	cpu_to_be64w((uint64_t*)(buf + 16), size);
       
   286 	memset(buf + 24, 0, 128);
       
   287 
       
   288 	if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
       
   289 		LOG("write failed");
       
   290 		errno = EINVAL;
       
   291 		return -1;
       
   292 	}
       
   293 
       
   294 	TRACE("Negotation succeeded.");
       
   295 
       
   296 	return 0;
       
   297 }
       
   298 
       
   299 int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
       
   300 {
       
   301 	char buf[8 + 8 + 8 + 128];
       
   302 	uint64_t magic;
       
   303 
       
   304 	TRACE("Receiving negotation.");
       
   305 
       
   306 	if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
       
   307 		LOG("read failed");
       
   308 		errno = EINVAL;
       
   309 		return -1;
       
   310 	}
       
   311 
       
   312 	magic = be64_to_cpup((uint64_t*)(buf + 8));
       
   313 	*size = be64_to_cpup((uint64_t*)(buf + 16));
       
   314 	*blocksize = 1024;
       
   315 
       
   316 	TRACE("Magic is %c%c%c%c%c%c%c%c",
       
   317 	      qemu_isprint(buf[0]) ? buf[0] : '.',
       
   318 	      qemu_isprint(buf[1]) ? buf[1] : '.',
       
   319 	      qemu_isprint(buf[2]) ? buf[2] : '.',
       
   320 	      qemu_isprint(buf[3]) ? buf[3] : '.',
       
   321 	      qemu_isprint(buf[4]) ? buf[4] : '.',
       
   322 	      qemu_isprint(buf[5]) ? buf[5] : '.',
       
   323 	      qemu_isprint(buf[6]) ? buf[6] : '.',
       
   324 	      qemu_isprint(buf[7]) ? buf[7] : '.');
       
   325 	TRACE("Magic is 0x%" PRIx64, magic);
       
   326 	TRACE("Size is %" PRIu64, *size);
       
   327 
       
   328 	if (memcmp(buf, "NBDMAGIC", 8) != 0) {
       
   329 		LOG("Invalid magic received");
       
   330 		errno = EINVAL;
       
   331 		return -1;
       
   332 	}
       
   333 
       
   334 	TRACE("Checking magic");
       
   335 
       
   336 	if (magic != 0x00420281861253LL) {
       
   337 		LOG("Bad magic received");
       
   338 		errno = EINVAL;
       
   339 		return -1;
       
   340 	}
       
   341         return 0;
       
   342 }
       
   343 
       
   344 #ifndef _WIN32
       
   345 int nbd_init(int fd, int csock, off_t size, size_t blocksize)
       
   346 {
       
   347 	TRACE("Setting block size to %lu", (unsigned long)blocksize);
       
   348 
       
   349 	if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {
       
   350 		int serrno = errno;
       
   351 		LOG("Failed setting NBD block size");
       
   352 		errno = serrno;
       
   353 		return -1;
       
   354 	}
       
   355 
       
   356 	TRACE("Setting size to %llu block(s)",
       
   357 	      (unsigned long long)(size / blocksize));
       
   358 
       
   359 	if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) == -1) {
       
   360 		int serrno = errno;
       
   361 		LOG("Failed setting size (in blocks)");
       
   362 		errno = serrno;
       
   363 		return -1;
       
   364 	}
       
   365 
       
   366 	TRACE("Clearing NBD socket");
       
   367 
       
   368 	if (ioctl(fd, NBD_CLEAR_SOCK) == -1) {
       
   369 		int serrno = errno;
       
   370 		LOG("Failed clearing NBD socket");
       
   371 		errno = serrno;
       
   372 		return -1;
       
   373 	}
       
   374 
       
   375 	TRACE("Setting NBD socket");
       
   376 
       
   377 	if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
       
   378 		int serrno = errno;
       
   379 		LOG("Failed to set NBD socket");
       
   380 		errno = serrno;
       
   381 		return -1;
       
   382 	}
       
   383 
       
   384 	TRACE("Negotiation ended");
       
   385 
       
   386 	return 0;
       
   387 }
       
   388 
       
   389 int nbd_disconnect(int fd)
       
   390 {
       
   391 	ioctl(fd, NBD_CLEAR_QUE);
       
   392 	ioctl(fd, NBD_DISCONNECT);
       
   393 	ioctl(fd, NBD_CLEAR_SOCK);
       
   394 	return 0;
       
   395 }
       
   396 
       
   397 int nbd_client(int fd, int csock)
       
   398 {
       
   399 	int ret;
       
   400 	int serrno;
       
   401 
       
   402 	TRACE("Doing NBD loop");
       
   403 
       
   404 	ret = ioctl(fd, NBD_DO_IT);
       
   405 	serrno = errno;
       
   406 
       
   407 	TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
       
   408 
       
   409 	TRACE("Clearing NBD queue");
       
   410 	ioctl(fd, NBD_CLEAR_QUE);
       
   411 
       
   412 	TRACE("Clearing NBD socket");
       
   413 	ioctl(fd, NBD_CLEAR_SOCK);
       
   414 
       
   415 	errno = serrno;
       
   416 	return ret;
       
   417 }
       
   418 #else
       
   419 int nbd_init(int fd, int csock, off_t size, size_t blocksize)
       
   420 {
       
   421     errno = ENOTSUP;
       
   422     return -1;
       
   423 }
       
   424 
       
   425 int nbd_disconnect(int fd)
       
   426 {
       
   427     errno = ENOTSUP;
       
   428     return -1;
       
   429 }
       
   430 
       
   431 int nbd_client(int fd, int csock)
       
   432 {
       
   433     errno = ENOTSUP;
       
   434     return -1;
       
   435 }
       
   436 #endif
       
   437 
       
   438 int nbd_send_request(int csock, struct nbd_request *request)
       
   439 {
       
   440 	uint8_t buf[4 + 4 + 8 + 8 + 4];
       
   441 
       
   442 	cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
       
   443 	cpu_to_be32w((uint32_t*)(buf + 4), request->type);
       
   444 	cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
       
   445 	cpu_to_be64w((uint64_t*)(buf + 16), request->from);
       
   446 	cpu_to_be32w((uint32_t*)(buf + 24), request->len);
       
   447 
       
   448 	TRACE("Sending request to client");
       
   449 
       
   450 	if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
       
   451 		LOG("writing to socket failed");
       
   452 		errno = EINVAL;
       
   453 		return -1;
       
   454 	}
       
   455 	return 0;
       
   456 }
       
   457 
       
   458 
       
   459 static int nbd_receive_request(int csock, struct nbd_request *request)
       
   460 {
       
   461 	uint8_t buf[4 + 4 + 8 + 8 + 4];
       
   462 	uint32_t magic;
       
   463 
       
   464 	if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
       
   465 		LOG("read failed");
       
   466 		errno = EINVAL;
       
   467 		return -1;
       
   468 	}
       
   469 
       
   470 	/* Request
       
   471 	   [ 0 ..  3]   magic   (NBD_REQUEST_MAGIC)
       
   472 	   [ 4 ..  7]   type    (0 == READ, 1 == WRITE)
       
   473 	   [ 8 .. 15]   handle
       
   474 	   [16 .. 23]   from
       
   475 	   [24 .. 27]   len
       
   476 	 */
       
   477 
       
   478 	magic = be32_to_cpup((uint32_t*)buf);
       
   479 	request->type  = be32_to_cpup((uint32_t*)(buf + 4));
       
   480 	request->handle = be64_to_cpup((uint64_t*)(buf + 8));
       
   481 	request->from  = be64_to_cpup((uint64_t*)(buf + 16));
       
   482 	request->len   = be32_to_cpup((uint32_t*)(buf + 24));
       
   483 
       
   484 	TRACE("Got request: "
       
   485 	      "{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
       
   486 	      magic, request->type, request->from, request->len);
       
   487 
       
   488 	if (magic != NBD_REQUEST_MAGIC) {
       
   489 		LOG("invalid magic (got 0x%x)", magic);
       
   490 		errno = EINVAL;
       
   491 		return -1;
       
   492 	}
       
   493 	return 0;
       
   494 }
       
   495 
       
   496 int nbd_receive_reply(int csock, struct nbd_reply *reply)
       
   497 {
       
   498 	uint8_t buf[4 + 4 + 8];
       
   499 	uint32_t magic;
       
   500 
       
   501 	memset(buf, 0xAA, sizeof(buf));
       
   502 
       
   503 	if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
       
   504 		LOG("read failed");
       
   505 		errno = EINVAL;
       
   506 		return -1;
       
   507 	}
       
   508 
       
   509 	/* Reply
       
   510 	   [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
       
   511 	   [ 4 ..  7]    error   (0 == no error)
       
   512 	   [ 7 .. 15]    handle
       
   513 	 */
       
   514 
       
   515 	magic = be32_to_cpup((uint32_t*)buf);
       
   516 	reply->error  = be32_to_cpup((uint32_t*)(buf + 4));
       
   517 	reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
       
   518 
       
   519 	TRACE("Got reply: "
       
   520 	      "{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
       
   521 	      magic, reply->error, reply->handle);
       
   522 
       
   523 	if (magic != NBD_REPLY_MAGIC) {
       
   524 		LOG("invalid magic (got 0x%x)", magic);
       
   525 		errno = EINVAL;
       
   526 		return -1;
       
   527 	}
       
   528 	return 0;
       
   529 }
       
   530 
       
   531 static int nbd_send_reply(int csock, struct nbd_reply *reply)
       
   532 {
       
   533 	uint8_t buf[4 + 4 + 8];
       
   534 
       
   535 	/* Reply
       
   536 	   [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
       
   537 	   [ 4 ..  7]    error   (0 == no error)
       
   538 	   [ 7 .. 15]    handle
       
   539 	 */
       
   540 	cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
       
   541 	cpu_to_be32w((uint32_t*)(buf + 4), reply->error);
       
   542 	cpu_to_be64w((uint64_t*)(buf + 8), reply->handle);
       
   543 
       
   544 	TRACE("Sending response to client");
       
   545 
       
   546 	if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
       
   547 		LOG("writing to socket failed");
       
   548 		errno = EINVAL;
       
   549 		return -1;
       
   550 	}
       
   551 	return 0;
       
   552 }
       
   553 
       
   554 int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
       
   555              off_t *offset, bool readonly, uint8_t *data, int data_size)
       
   556 {
       
   557 	struct nbd_request request;
       
   558 	struct nbd_reply reply;
       
   559 
       
   560 	TRACE("Reading request.");
       
   561 
       
   562 	if (nbd_receive_request(csock, &request) == -1)
       
   563 		return -1;
       
   564 
       
   565 	if (request.len > data_size) {
       
   566 		LOG("len (%u) is larger than max len (%u)",
       
   567 		    request.len, data_size);
       
   568 		errno = EINVAL;
       
   569 		return -1;
       
   570 	}
       
   571 
       
   572 	if ((request.from + request.len) < request.from) {
       
   573 		LOG("integer overflow detected! "
       
   574 		    "you're probably being attacked");
       
   575 		errno = EINVAL;
       
   576 		return -1;
       
   577 	}
       
   578 
       
   579 	if ((request.from + request.len) > size) {
       
   580 	        LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
       
   581 		    ", Offset: %" PRIu64 "\n",
       
   582 		     request.from, request.len, size, dev_offset);
       
   583 		LOG("requested operation past EOF--bad client?");
       
   584 		errno = EINVAL;
       
   585 		return -1;
       
   586 	}
       
   587 
       
   588 	TRACE("Decoding type");
       
   589 
       
   590 	reply.handle = request.handle;
       
   591 	reply.error = 0;
       
   592 
       
   593 	switch (request.type) {
       
   594 	case NBD_CMD_READ:
       
   595 		TRACE("Request type is READ");
       
   596 
       
   597 		if (bdrv_read(bs, (request.from + dev_offset) / 512, data,
       
   598 			      request.len / 512) == -1) {
       
   599 			LOG("reading from file failed");
       
   600 			errno = EINVAL;
       
   601 			return -1;
       
   602 		}
       
   603 		*offset += request.len;
       
   604 
       
   605 		TRACE("Read %u byte(s)", request.len);
       
   606 
       
   607 		if (nbd_send_reply(csock, &reply) == -1)
       
   608 			return -1;
       
   609 
       
   610 		TRACE("Sending data to client");
       
   611 
       
   612 		if (write_sync(csock, data, request.len) != request.len) {
       
   613 			LOG("writing to socket failed");
       
   614 			errno = EINVAL;
       
   615 			return -1;
       
   616 		}
       
   617 		break;
       
   618 	case NBD_CMD_WRITE:
       
   619 		TRACE("Request type is WRITE");
       
   620 
       
   621 		TRACE("Reading %u byte(s)", request.len);
       
   622 
       
   623 		if (read_sync(csock, data, request.len) != request.len) {
       
   624 			LOG("reading from socket failed");
       
   625 			errno = EINVAL;
       
   626 			return -1;
       
   627 		}
       
   628 
       
   629 		if (readonly) {
       
   630 			TRACE("Server is read-only, return error");
       
   631 			reply.error = 1;
       
   632 		} else {
       
   633 			TRACE("Writing to device");
       
   634 
       
   635 			if (bdrv_write(bs, (request.from + dev_offset) / 512,
       
   636 				       data, request.len / 512) == -1) {
       
   637 				LOG("writing to file failed");
       
   638 				errno = EINVAL;
       
   639 				return -1;
       
   640 			}
       
   641 
       
   642 			*offset += request.len;
       
   643 		}
       
   644 
       
   645 		if (nbd_send_reply(csock, &reply) == -1)
       
   646 			return -1;
       
   647 		break;
       
   648 	case NBD_CMD_DISC:
       
   649 		TRACE("Request type is DISCONNECT");
       
   650 		errno = 0;
       
   651 		return 1;
       
   652 	default:
       
   653 		LOG("invalid request type (%u) received", request.type);
       
   654 		errno = EINVAL;
       
   655 		return -1;
       
   656 	}
       
   657 
       
   658 	TRACE("Request/Reply complete");
       
   659 
       
   660 	return 0;
       
   661 }