source3/libsmb/clireadwrite.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    client file read/write routines
   4    Copyright (C) Andrew Tridgell 1994-1998
   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; either version 3 of the License, or
   9    (at your option) any later version.
  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 "includes.h"
  21
  22 /****************************************************************************
  23   Calculate the recommended read buffer size
  24 ****************************************************************************/
  25 static size_t cli_read_max_bufsize(struct cli_state *cli)
  26 {
  27         if (!client_is_signing_on(cli) && !cli_encryption_on(cli)
  28             && (cli->posix_capabilities & CIFS_UNIX_LARGE_READ_CAP)) {
  29                 return CLI_SAMBA_MAX_POSIX_LARGE_READX_SIZE;
  30         }
  31         if (cli->capabilities & CAP_LARGE_READX) {
  32                 return cli->is_samba
  33                         ? CLI_SAMBA_MAX_LARGE_READX_SIZE
  34                         : CLI_WINDOWS_MAX_LARGE_READX_SIZE;
  35         }
  36         return (cli->max_xmit - (smb_size+32)) & ~1023;
  37 }
  38
  39 /****************************************************************************
  40   Calculate the recommended write buffer size
  41 ****************************************************************************/
  42 static size_t cli_write_max_bufsize(struct cli_state *cli, uint16_t write_mode)
  43 {
  44         if (write_mode == 0 &&
  45             !client_is_signing_on(cli) &&
  46             !cli_encryption_on(cli) &&
  47             (cli->posix_capabilities & CIFS_UNIX_LARGE_WRITE_CAP) &&
  48             (cli->capabilities & CAP_LARGE_FILES)) {
  49                 /* Only do massive writes if we can do them direct
  50                  * with no signing or encrypting - not on a pipe. */
  51                 return CLI_SAMBA_MAX_POSIX_LARGE_WRITEX_SIZE;
  52         }
  53
  54         if (cli->is_samba) {
  55                 return CLI_SAMBA_MAX_LARGE_WRITEX_SIZE;
  56         }
  57
  58         if (((cli->capabilities & CAP_LARGE_WRITEX) == 0)
  59             || client_is_signing_on(cli)
  60             || strequal(cli->dev, "LPT1:")) {
  61
  62                 /*
  63                  * Printer devices are restricted to max_xmit writesize in
  64                  * Vista and XPSP3 as are signing connections.
  65                  */
  66
  67                 return (cli->max_xmit - (smb_size+32)) & ~1023;
  68         }
  69
  70         return CLI_WINDOWS_MAX_LARGE_WRITEX_SIZE;
  71 }
  72
  73
  74 /*
  75  * Send a read&x request
  76  */
  77
  78 struct async_req *cli_read_andx_send(TALLOC_CTX *mem_ctx,
  79                                      struct event_context *ev,
  80                                      struct cli_state *cli, int fnum,
  81                                      off_t offset, size_t size)
  82 {
  83         struct async_req *result;
  84         struct cli_request *req;
  85         bool bigoffset = False;
  86
  87         uint16_t vwv[12];
  88         uint8_t wct = 10;
  89
  90         if (size > cli_read_max_bufsize(cli)) {
  91                 DEBUG(0, ("cli_read_andx_send got size=%d, can only handle "
  92                           "size=%d\n", (int)size,
  93                           (int)cli_read_max_bufsize(cli)));
  94                 return NULL;
  95         }
  96
  97         SCVAL(vwv + 0, 0, 0xFF);
  98         SCVAL(vwv + 0, 1, 0);
  99         SSVAL(vwv + 1, 0, 0);
 100         SSVAL(vwv + 2, 0, fnum);
 101         SIVAL(vwv + 3, 0, offset);
 102         SSVAL(vwv + 5, 0, size);
 103         SSVAL(vwv + 6, 0, size);
 104         SSVAL(vwv + 7, 0, (size >> 16));
 105         SSVAL(vwv + 8, 0, 0);
 106         SSVAL(vwv + 9, 0, 0);
 107
 108         if ((uint64_t)offset >> 32) {
 109                 bigoffset = True;
 110                 SIVAL(vwv + 10, 0,
 111                       (((uint64_t)offset)>>32) & 0xffffffff);
 112                 wct += 2;
 113         }
 114
 115         result = cli_request_send(mem_ctx, ev, cli, SMBreadX, 0, wct, vwv, 0,
 116                                   0, NULL);
 117         if (result == NULL) {
 118                 return NULL;
 119         }
 120
 121         req = talloc_get_type_abort(result->private_data, struct cli_request);
 122
 123         req->data.read.ofs = offset;
 124         req->data.read.size = size;
 125         req->data.read.received = 0;
 126         req->data.read.rcvbuf = NULL;
 127
 128         return result;
 129 }
 130
 131 /*
 132  * Pull the data out of a finished async read_and_x request. rcvbuf is
 133  * talloced from the request, so better make sure that you copy it away before
 134  * you talloc_free(req). "rcvbuf" is NOT a talloc_ctx of its own, so do not
 135  * talloc_move it!
 136  */
 137
 138 NTSTATUS cli_read_andx_recv(struct async_req *req, ssize_t *received,
 139                             uint8_t **rcvbuf)
 140 {
 141         struct cli_request *cli_req = talloc_get_type_abort(
 142                 req->private_data, struct cli_request);
 143         uint8_t wct;
 144         uint16_t *vwv;
 145         uint16_t num_bytes;
 146         uint8_t *bytes;
 147         uint8_t *buf;
 148         NTSTATUS status;
 149         size_t size;
 150
 151         if (async_req_is_error(req, &status)) {
 152                 return status;
 153         }
 154
 155         status = cli_pull_reply(req, &wct, &vwv, &num_bytes, &bytes);
 156
 157         if (NT_STATUS_IS_ERR(status)) {
 158                 return status;
 159         }
 160
 161         if (wct < 12) {
 162                 return NT_STATUS_INVALID_NETWORK_RESPONSE;
 163         }
 164
 165         /* size is the number of bytes the server returned.
 166          * Might be zero. */
 167         size = SVAL(vwv + 5, 0);
 168         size |= (((unsigned int)SVAL(vwv + 7, 0)) << 16);
 169
 170         if (size > cli_req->data.read.size) {
 171                 DEBUG(5,("server returned more than we wanted!\n"));
 172                 return NT_STATUS_UNEXPECTED_IO_ERROR;
 173         }
 174
 175         /*
 176          * bcc field must be valid for small reads, for large reads the 16-bit
 177          * bcc field can't be correct.
 178          */
 179
 180         if ((size < 0xffff) && (size > num_bytes)) {
 181                 DEBUG(5, ("server announced more bytes than sent\n"));
 182                 return NT_STATUS_INVALID_NETWORK_RESPONSE;
 183         }
 184
 185         buf = (uint8_t *)smb_base(cli_req->inbuf) + SVAL(vwv+6, 0);
 186
 187         if (trans_oob(smb_len(cli_req->inbuf), SVAL(vwv+6, 0), size)
 188             || (buf < bytes)) {
 189                 DEBUG(5, ("server returned invalid read&x data offset\n"));
 190                 return NT_STATUS_INVALID_NETWORK_RESPONSE;
 191         }
 192
 193         *rcvbuf = (uint8_t *)(smb_base(cli_req->inbuf) + SVAL(vwv + 6, 0));
 194         *received = size;
 195         return NT_STATUS_OK;
 196 }
 197
 198 /*
 199  * Parallel read support.
 200  *
 201  * cli_pull sends as many read&x requests as the server would allow via
 202  * max_mux at a time. When replies flow back in, the data is written into
 203  * the callback function "sink" in the right order.
 204  */
 205
 206 struct cli_pull_state {
 207         struct async_req *req;
 208
 209         struct event_context *ev;
 210         struct cli_state *cli;
 211         uint16_t fnum;
 212         off_t start_offset;
 213         SMB_OFF_T size;
 214
 215         NTSTATUS (*sink)(char *buf, size_t n, void *priv);
 216         void *priv;
 217
 218         size_t chunk_size;
 219
 220         /*
 221          * Outstanding requests
 222          */
 223         int num_reqs;
 224         struct async_req **reqs;
 225
 226         /*
 227          * For how many bytes did we send requests already?
 228          */
 229         SMB_OFF_T requested;
 230
 231         /*
 232          * Next request index to push into "sink". This walks around the "req"
 233          * array, taking care that the requests are pushed to "sink" in the
 234          * right order. If necessary (i.e. replies don't come in in the right
 235          * order), replies are held back in "reqs".
 236          */
 237         int top_req;
 238
 239         /*
 240          * How many bytes did we push into "sink"?
 241          */
 242
 243         SMB_OFF_T pushed;
 244 };
 245
 246 static char *cli_pull_print(TALLOC_CTX *mem_ctx, struct async_req *req)
 247 {
 248         struct cli_pull_state *state = talloc_get_type_abort(
 249                 req->private_data, struct cli_pull_state);
 250         char *result;
 251
 252         result = async_req_print(mem_ctx, req);
 253         if (result == NULL) {
 254                 return NULL;
 255         }
 256
 257         return talloc_asprintf_append_buffer(
 258                 result, "num_reqs=%d, top_req=%d",
 259                 state->num_reqs, state->top_req);
 260 }
 261
 262 static void cli_pull_read_done(struct async_req *read_req);
 263
 264 /*
 265  * Prepare an async pull request
 266  */
 267
 268 struct async_req *cli_pull_send(TALLOC_CTX *mem_ctx,
 269                                 struct event_context *ev,
 270                                 struct cli_state *cli,
 271                                 uint16_t fnum, off_t start_offset,
 272                                 SMB_OFF_T size, size_t window_size,
 273                                 NTSTATUS (*sink)(char *buf, size_t n,
 274                                                  void *priv),
 275                                 void *priv)
 276 {
 277         struct async_req *result;
 278         struct cli_pull_state *state;
 279         int i;
 280
 281         result = async_req_new(mem_ctx, ev);
 282         if (result == NULL) {
 283                 goto failed;
 284         }
 285         state = talloc(result, struct cli_pull_state);
 286         if (state == NULL) {
 287                 goto failed;
 288         }
 289         result->private_data = state;
 290         result->print = cli_pull_print;
 291         state->req = result;
 292
 293         state->cli = cli;
 294         state->ev = ev;
 295         state->fnum = fnum;
 296         state->start_offset = start_offset;
 297         state->size = size;
 298         state->sink = sink;
 299         state->priv = priv;
 300
 301         state->pushed = 0;
 302         state->top_req = 0;
 303
 304         if (size == 0) {
 305                 if (!async_post_status(result, NT_STATUS_OK)) {
 306                         goto failed;
 307                 }
 308                 return result;
 309         }
 310
 311         state->chunk_size = cli_read_max_bufsize(cli);
 312
 313         state->num_reqs = MAX(window_size/state->chunk_size, 1);
 314         state->num_reqs = MIN(state->num_reqs, cli->max_mux);
 315
 316         state->reqs = TALLOC_ZERO_ARRAY(state, struct async_req *,
 317                                         state->num_reqs);
 318         if (state->reqs == NULL) {
 319                 goto failed;
 320         }
 321
 322         state->requested = 0;
 323
 324         for (i=0; i<state->num_reqs; i++) {
 325                 SMB_OFF_T size_left;
 326                 size_t request_thistime;
 327
 328                 if (state->requested >= size) {
 329                         state->num_reqs = i;
 330                         break;
 331                 }
 332
 333                 size_left = size - state->requested;
 334                 request_thistime = MIN(size_left, state->chunk_size);
 335
 336                 state->reqs[i] = cli_read_andx_send(
 337                         state->reqs, ev, cli, fnum,
 338                         state->start_offset + state->requested,
 339                         request_thistime);
 340
 341                 if (state->reqs[i] == NULL) {
 342                         goto failed;
 343                 }
 344
 345                 state->reqs[i]->async.fn = cli_pull_read_done;
 346                 state->reqs[i]->async.priv = result;
 347
 348                 state->requested += request_thistime;
 349         }
 350         return result;
 351
 352 failed:
 353         TALLOC_FREE(result);
 354         return NULL;
 355 }
 356
 357 /*
 358  * Handle incoming read replies, push the data into sink and send out new
 359  * requests if necessary.
 360  */
 361
 362 static void cli_pull_read_done(struct async_req *read_req)
 363 {
 364         struct async_req *pull_req = talloc_get_type_abort(
 365                 read_req->async.priv, struct async_req);
 366         struct cli_pull_state *state = talloc_get_type_abort(
 367                 pull_req->private_data, struct cli_pull_state);
 368         struct cli_request *read_state = talloc_get_type_abort(
 369                 read_req->private_data, struct cli_request);
 370         NTSTATUS status;
 371
 372         status = cli_read_andx_recv(read_req, &read_state->data.read.received,
 373                                     &read_state->data.read.rcvbuf);
 374         if (!NT_STATUS_IS_OK(status)) {
 375                 async_req_error(state->req, status);
 376                 return;
 377         }
 378
 379         /*
 380          * This loop is the one to take care of out-of-order replies. All
 381          * pending requests are in state->reqs, state->reqs[top_req] is the
 382          * one that is to be pushed next. If however a request later than
 383          * top_req is replied to, then we can't push yet. If top_req is
 384          * replied to at a later point then, we need to push all the finished
 385          * requests.
 386          */
 387
 388         while (state->reqs[state->top_req] != NULL) {
 389                 struct cli_request *top_read;
 390
 391                 DEBUG(11, ("cli_pull_read_done: top_req = %d\n",
 392                            state->top_req));
 393
 394                 if (state->reqs[state->top_req]->state < ASYNC_REQ_DONE) {
 395                         DEBUG(11, ("cli_pull_read_done: top request not yet "
 396                                    "done\n"));
 397                         return;
 398                 }
 399
 400                 top_read = talloc_get_type_abort(
 401                         state->reqs[state->top_req]->private_data,
 402                         struct cli_request);
 403
 404                 DEBUG(10, ("cli_pull_read_done: Pushing %d bytes, %d already "
 405                            "pushed\n", (int)top_read->data.read.received,
 406                            (int)state->pushed));
 407
 408                 status = state->sink((char *)top_read->data.read.rcvbuf,
 409                                      top_read->data.read.received,
 410                                      state->priv);
 411                 if (!NT_STATUS_IS_OK(status)) {
 412                         async_req_error(state->req, status);
 413                         return;
 414                 }
 415                 state->pushed += top_read->data.read.received;
 416
 417                 TALLOC_FREE(state->reqs[state->top_req]);
 418
 419                 if (state->requested < state->size) {
 420                         struct async_req *new_req;
 421                         SMB_OFF_T size_left;
 422                         size_t request_thistime;
 423
 424                         size_left = state->size - state->requested;
 425                         request_thistime = MIN(size_left, state->chunk_size);
 426
 427                         DEBUG(10, ("cli_pull_read_done: Requesting %d bytes "
 428                                    "at %d, position %d\n",
 429                                    (int)request_thistime,
 430                                    (int)(state->start_offset
 431                                          + state->requested),
 432                                    state->top_req));
 433
 434                         new_req = cli_read_andx_send(
 435                                 state->reqs, state->ev, state->cli,
 436                                 state->fnum,
 437                                 state->start_offset + state->requested,
 438                                 request_thistime);
 439
 440                         if (async_req_nomem(new_req, state->req)) {
 441                                 return;
 442                         }
 443
 444                         new_req->async.fn = cli_pull_read_done;
 445                         new_req->async.priv = pull_req;
 446
 447                         state->reqs[state->top_req] = new_req;
 448                         state->requested += request_thistime;
 449                 }
 450
 451                 state->top_req = (state->top_req+1) % state->num_reqs;
 452         }
 453
 454         async_req_done(pull_req);
 455 }
 456
 457 NTSTATUS cli_pull_recv(struct async_req *req, SMB_OFF_T *received)
 458 {
 459         struct cli_pull_state *state = talloc_get_type_abort(
 460                 req->private_data, struct cli_pull_state);
 461         NTSTATUS status;
 462
 463         if (async_req_is_error(req, &status)) {
 464                 return status;
 465         }
 466         *received = state->pushed;
 467         return NT_STATUS_OK;
 468 }
 469
 470 NTSTATUS cli_pull(struct cli_state *cli, uint16_t fnum,
 471                   off_t start_offset, SMB_OFF_T size, size_t window_size,
 472                   NTSTATUS (*sink)(char *buf, size_t n, void *priv),
 473                   void *priv, SMB_OFF_T *received)
 474 {
 475         TALLOC_CTX *frame = talloc_stackframe();
 476         struct event_context *ev;
 477         struct async_req *req;
 478         NTSTATUS result = NT_STATUS_NO_MEMORY;
 479
 480         if (cli->fd_event != NULL) {
 481                 /*
 482                  * Can't use sync call while an async call is in flight
 483                  */
 484                 return NT_STATUS_INVALID_PARAMETER;
 485         }
 486
 487         ev = event_context_init(frame);
 488         if (ev == NULL) {
 489                 goto nomem;
 490         }
 491
 492         req = cli_pull_send(frame, ev, cli, fnum, start_offset, size,
 493                             window_size, sink, priv);
 494         if (req == NULL) {
 495                 goto nomem;
 496         }
 497
 498         while (req->state < ASYNC_REQ_DONE) {
 499                 event_loop_once(ev);
 500         }
 501
 502         result = cli_pull_recv(req, received);
 503  nomem:
 504         TALLOC_FREE(frame);
 505         return result;
 506 }
 507
 508 static NTSTATUS cli_read_sink(char *buf, size_t n, void *priv)
 509 {
 510         char **pbuf = (char **)priv;
 511         memcpy(*pbuf, buf, n);
 512         *pbuf += n;
 513         return NT_STATUS_OK;
 514 }
 515
 516 ssize_t cli_read(struct cli_state *cli, int fnum, char *buf,
 517                  off_t offset, size_t size)
 518 {
 519         NTSTATUS status;
 520         SMB_OFF_T ret;
 521
 522         status = cli_pull(cli, fnum, offset, size, size,
 523                           cli_read_sink, &buf, &ret);
 524         if (!NT_STATUS_IS_OK(status)) {
 525                 cli_set_error(cli, status);
 526                 return -1;
 527         }
 528         return ret;
 529 }
 530
 531 /****************************************************************************
 532  Issue a single SMBwrite and don't wait for a reply.
 533 ****************************************************************************/
 534
 535 static bool cli_issue_write(struct cli_state *cli,
 536                                 int fnum,
 537                                 off_t offset,
 538                                 uint16 mode,
 539                                 const char *buf,
 540                                 size_t size,
 541                                 int i)
 542 {
 543         char *p;
 544         bool large_writex = false;
 545         /* We can only do direct writes if not signing and not encrypting. */
 546         bool direct_writes = !client_is_signing_on(cli) && !cli_encryption_on(cli);
 547
 548         if (!direct_writes && size + 1 > cli->bufsize) {
 549                 cli->outbuf = (char *)SMB_REALLOC(cli->outbuf, size + 1024);
 550                 if (!cli->outbuf) {
 551                         return False;
 552                 }
 553                 cli->inbuf = (char *)SMB_REALLOC(cli->inbuf, size + 1024);
 554                 if (cli->inbuf == NULL) {
 555                         SAFE_FREE(cli->outbuf);
 556                         return False;
 557                 }
 558                 cli->bufsize = size + 1024;
 559         }
 560
 561         memset(cli->outbuf,'\0',smb_size);
 562         memset(cli->inbuf,'\0',smb_size);
 563
 564         if (cli->capabilities & CAP_LARGE_FILES) {
 565                 large_writex = True;
 566         }
 567
 568         if (large_writex) {
 569                 cli_set_message(cli->outbuf,14,0,True);
 570         } else {
 571                 cli_set_message(cli->outbuf,12,0,True);
 572         }
 573
 574         SCVAL(cli->outbuf,smb_com,SMBwriteX);
 575         SSVAL(cli->outbuf,smb_tid,cli->cnum);
 576         cli_setup_packet(cli);
 577
 578         SCVAL(cli->outbuf,smb_vwv0,0xFF);
 579         SSVAL(cli->outbuf,smb_vwv2,fnum);
 580
 581         SIVAL(cli->outbuf,smb_vwv3,offset);
 582         SIVAL(cli->outbuf,smb_vwv5,0);
 583         SSVAL(cli->outbuf,smb_vwv7,mode);
 584
 585         SSVAL(cli->outbuf,smb_vwv8,(mode & 0x0008) ? size : 0);
 586         /*
 587          * According to CIFS-TR-1p00, this following field should only
 588          * be set if CAP_LARGE_WRITEX is set. We should check this
 589          * locally. However, this check might already have been
 590          * done by our callers.
 591          */
 592         SSVAL(cli->outbuf,smb_vwv9,(size>>16));
 593         SSVAL(cli->outbuf,smb_vwv10,size);
 594         /* +1 is pad byte. */
 595         SSVAL(cli->outbuf,smb_vwv11,
 596               smb_buf(cli->outbuf) - smb_base(cli->outbuf) + 1);
 597
 598         if (large_writex) {
 599                 SIVAL(cli->outbuf,smb_vwv12,(((uint64_t)offset)>>32) & 0xffffffff);
 600         }
 601
 602         p = smb_base(cli->outbuf) + SVAL(cli->outbuf,smb_vwv11) -1;
 603         *p++ = '\0'; /* pad byte. */
 604         if (!direct_writes) {
 605                 memcpy(p, buf, size);
 606         }
 607         if (size > 0x1FFFF) {
 608                 /* This is a POSIX 14 word large write. */
 609                 set_message_bcc(cli->outbuf, 0); /* Set bcc to zero. */
 610                 _smb_setlen_large(cli->outbuf,smb_size + 28 + 1 /* pad */ + size - 4);
 611         } else {
 612                 cli_setup_bcc(cli, p+size);
 613         }
 614
 615         SSVAL(cli->outbuf,smb_mid,cli->mid + i);
 616
 617         show_msg(cli->outbuf);
 618         if (direct_writes) {
 619                 /* For direct writes we now need to write the data
 620                  * directly out of buf. */
 621                 return cli_send_smb_direct_writeX(cli, buf, size);
 622         } else {
 623                 return cli_send_smb(cli);
 624         }
 625 }
 626
 627 /****************************************************************************
 628   write to a file
 629   write_mode: 0x0001 disallow write cacheing
 630               0x0002 return bytes remaining
 631               0x0004 use raw named pipe protocol
 632               0x0008 start of message mode named pipe protocol
 633 ****************************************************************************/
 634
 635 ssize_t cli_write(struct cli_state *cli,
 636                  int fnum, uint16 write_mode,
 637                  const char *buf, off_t offset, size_t size)
 638 {
 639         ssize_t bwritten = 0;
 640         unsigned int issued = 0;
 641         unsigned int received = 0;
 642         int mpx = 1;
 643         size_t writesize;
 644         int blocks;
 645
 646         if(cli->max_mux > 1) {
 647                 mpx = cli->max_mux-1;
 648         } else {
 649                 mpx = 1;
 650         }
 651
 652         writesize = cli_write_max_bufsize(cli, write_mode);
 653
 654         blocks = (size + (writesize-1)) / writesize;
 655
 656         while (received < blocks) {
 657
 658                 while ((issued - received < mpx) && (issued < blocks)) {
 659                         ssize_t bsent = issued * writesize;
 660                         ssize_t size1 = MIN(writesize, size - bsent);
 661
 662                         if (!cli_issue_write(cli, fnum, offset + bsent,
 663                                         write_mode,
 664                                         buf + bsent,
 665                                         size1, issued))
 666                                 return -1;
 667                         issued++;
 668                 }
 669
 670                 if (!cli_receive_smb(cli)) {
 671                         return bwritten;
 672                 }
 673
 674                 received++;
 675
 676                 if (cli_is_error(cli))
 677                         break;
 678
 679                 bwritten += SVAL(cli->inbuf, smb_vwv2);
 680                 if (writesize > 0xFFFF) {
 681                         bwritten += (((int)(SVAL(cli->inbuf, smb_vwv4)))<<16);
 682                 }
 683         }
 684
 685         while (received < issued && cli_receive_smb(cli)) {
 686                 received++;
 687         }
 688
 689         return bwritten;
 690 }
 691
 692 /****************************************************************************
 693   write to a file using a SMBwrite and not bypassing 0 byte writes
 694 ****************************************************************************/
 695
 696 ssize_t cli_smbwrite(struct cli_state *cli,
 697                      int fnum, char *buf, off_t offset, size_t size1)
 698 {
 699         char *p;
 700         ssize_t total = 0;
 701
 702         do {
 703                 size_t size = MIN(size1, cli->max_xmit - 48);
 704
 705                 memset(cli->outbuf,'\0',smb_size);
 706                 memset(cli->inbuf,'\0',smb_size);
 707
 708                 cli_set_message(cli->outbuf,5, 0,True);
 709
 710                 SCVAL(cli->outbuf,smb_com,SMBwrite);
 711                 SSVAL(cli->outbuf,smb_tid,cli->cnum);
 712                 cli_setup_packet(cli);
 713
 714                 SSVAL(cli->outbuf,smb_vwv0,fnum);
 715                 SSVAL(cli->outbuf,smb_vwv1,size);
 716                 SIVAL(cli->outbuf,smb_vwv2,offset);
 717                 SSVAL(cli->outbuf,smb_vwv4,0);
 718
 719                 p = smb_buf(cli->outbuf);
 720                 *p++ = 1;
 721                 SSVAL(p, 0, size); p += 2;
 722                 memcpy(p, buf + total, size); p += size;
 723
 724                 cli_setup_bcc(cli, p);
 725
 726                 if (!cli_send_smb(cli))
 727                         return -1;
 728
 729                 if (!cli_receive_smb(cli))
 730                         return -1;
 731
 732                 if (cli_is_error(cli))
 733                         return -1;
 734
 735                 size = SVAL(cli->inbuf,smb_vwv0);
 736                 if (size == 0)
 737                         break;
 738
 739                 size1 -= size;
 740                 total += size;
 741                 offset += size;
 742
 743         } while (size1);
 744
 745         return total;
 746 }