source3/rpc_parse/parse_prs.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    Samba memory buffer functions
   5    Copyright (C) Andrew Tridgell              1992-1997
   6    Copyright (C) Luke Kenneth Casson Leighton 1996-1997
   7    Copyright (C) Jeremy Allison 1999.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 2 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 extern int DEBUGLEVEL;
  25
  26 #include "includes.h"
  27
  28
  29 /*******************************************************************
  30 dump a prs to a file
  31  ********************************************************************/
  32 void prs_dump(char *name, int v, prs_struct *ps)
  33 {
  34         int fd, i;
  35         pstring fname;
  36         if (DEBUGLEVEL < 50) return;
  37         for (i=1;i<100;i++) {
  38                 if (v != -1) {
  39                         slprintf(fname,sizeof(fname), "/tmp/%s_%d.%d.prs", name, v, i);
  40                 } else {
  41                         slprintf(fname,sizeof(fname), "/tmp/%s.%d.prs", name, i);
  42                 }
  43                 fd = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0644);
  44                 if (fd != -1 || errno != EEXIST) break;
  45         }
  46         if (fd != -1) {
  47                 write(fd, ps->data_p + ps->data_offset, ps->buffer_size - ps->data_offset);
  48                 close(fd);
  49                 DEBUG(0,("created %s\n", fname));
  50         }
  51 }
  52
  53
  54
  55 /*******************************************************************
  56  debug output for parsing info.
  57
  58  XXXX side-effect of this function is to increase the debug depth XXXX
  59
  60  ********************************************************************/
  61 void prs_debug(prs_struct *ps, int depth, char *desc, char *fn_name)
  62 {
  63         DEBUG(5+depth, ("%s%06x %s %s\n", tab_depth(depth), ps->data_offset, fn_name, desc));
  64 }
  65
  66
  67 /*******************************************************************
  68  Initialise a parse structure - malloc the data if requested.
  69  ********************************************************************/
  70 BOOL prs_init(prs_struct *ps, uint32 size, uint8 align, TALLOC_CTX *ctx, BOOL io)
  71 {
  72         ZERO_STRUCTP(ps);
  73         ps->io = io;
  74         ps->bigendian_data = False;
  75         ps->align = align;
  76         ps->is_dynamic = False;
  77         ps->data_offset = 0;
  78         ps->buffer_size = 0;
  79         ps->data_p = NULL;
  80         ps->mem_ctx = ctx;
  81
  82         if (size != 0) {
  83                 ps->buffer_size = size;
  84                 if((ps->data_p = (char *)malloc((size_t)size)) == NULL) {
  85                         DEBUG(0,("prs_init: malloc fail for %u bytes.\n", (unsigned int)size));
  86                         return False;
  87                 }
  88                 ps->is_dynamic = True; /* We own this memory. */
  89         }
  90
  91         return True;
  92 }
  93
  94 /*******************************************************************
  95  read from a socket into memory.
  96  ********************************************************************/
  97 BOOL prs_read(prs_struct *ps, int fd, size_t len, int timeout)
  98 {
  99         BOOL ok;
 100         size_t prev_size = ps->buffer_size;
 101         if (!prs_grow(ps, len))
 102                 return False;
 103
 104         if (timeout > 0) {
 105                 ok = (read_with_timeout(fd, &ps->data_p[prev_size],
 106                                             len, len,timeout) == len);
 107         } else {
 108                 ok = (read_data(fd, &ps->data_p[prev_size], len) == len);
 109         }
 110         return ok;
 111 }
 112
 113 /*******************************************************************
 114  Delete the memory in a parse structure - if we own it.
 115  ********************************************************************/
 116
 117 void prs_mem_free(prs_struct *ps)
 118 {
 119         if(ps->is_dynamic && (ps->data_p != NULL))
 120                 free(ps->data_p);
 121         ps->is_dynamic = False;
 122         ps->data_p = NULL;
 123         ps->buffer_size = 0;
 124         ps->data_offset = 0;
 125 }
 126
 127 /*******************************************************************
 128  Allocate memory when unmarshalling...
 129  ********************************************************************/
 130
 131 char *prs_alloc_mem(prs_struct *ps, size_t size)
 132 {
 133         return talloc(ps->mem_ctx, size);
 134 }
 135
 136 /*******************************************************************
 137  Return the current talloc context we're using.
 138  ********************************************************************/
 139
 140 TALLOC_CTX *prs_get_mem_context(prs_struct *ps)
 141 {
 142         return ps->mem_ctx;
 143 }
 144
 145 /*******************************************************************
 146  Hand some already allocated memory to a prs_struct.
 147  ********************************************************************/
 148
 149 void prs_give_memory(prs_struct *ps, char *buf, uint32 size, BOOL is_dynamic)
 150 {
 151         ps->is_dynamic = is_dynamic;
 152         ps->data_p = buf;
 153         ps->buffer_size = size;
 154 }
 155
 156 /*******************************************************************
 157  Take some memory back from a prs_struct.
 158  ********************************************************************/
 159
 160 char *prs_take_memory(prs_struct *ps, uint32 *psize)
 161 {
 162         char *ret = ps->data_p;
 163         if(psize)
 164                 *psize = ps->buffer_size;
 165         ps->is_dynamic = False;
 166         prs_mem_free(ps);
 167         return ret;
 168 }
 169
 170 /*******************************************************************
 171  Set a prs_struct to exactly a given size. Will grow or tuncate if neccessary.
 172  ********************************************************************/
 173
 174 BOOL prs_set_buffer_size(prs_struct *ps, uint32 newsize)
 175 {
 176         if (newsize > ps->buffer_size)
 177                 return prs_force_grow(ps, newsize - ps->buffer_size);
 178
 179         if (newsize < ps->buffer_size) {
 180                 char *new_data_p = Realloc(ps->data_p, newsize);
 181                 /* if newsize is zero, Realloc acts like free() & returns NULL*/
 182                 if (new_data_p == NULL && newsize != 0) {
 183                         DEBUG(0,("prs_set_buffer_size: Realloc failure for size %u.\n",
 184                                 (unsigned int)newsize));
 185                         DEBUG(0,("prs_set_buffer_size: Reason %s\n",strerror(errno)));
 186                         return False;
 187                 }
 188                 ps->data_p = new_data_p;
 189                 ps->buffer_size = newsize;
 190         }
 191
 192         return True;
 193 }
 194
 195 /*******************************************************************
 196  Attempt, if needed, to grow a data buffer.
 197  Also depends on the data stream mode (io).
 198  ********************************************************************/
 199
 200 BOOL prs_grow(prs_struct *ps, uint32 extra_space)
 201 {
 202         uint32 new_size;
 203         char *new_data;
 204
 205         ps->grow_size = MAX(ps->grow_size, ps->data_offset + extra_space);
 206
 207         if(ps->data_offset + extra_space <= ps->buffer_size)
 208                 return True;
 209
 210         /*
 211          * We cannot grow the buffer if we're not reading
 212          * into the prs_struct, or if we don't own the memory.
 213          */
 214
 215         if(UNMARSHALLING(ps) || !ps->is_dynamic) {
 216                 DEBUG(0,("prs_grow: Buffer overflow - unable to expand buffer by %u bytes.\n",
 217                                 (unsigned int)extra_space));
 218                 return False;
 219         }
 220
 221         /*
 222          * Decide how much extra space we really need.
 223          */
 224
 225         extra_space -= (ps->buffer_size - ps->data_offset);
 226         if(ps->buffer_size == 0) {
 227                 /*
 228                  * Ensure we have at least a PDU's length, or extra_space, whichever
 229                  * is greater.
 230                  */
 231
 232                 new_size = MAX(MAX_PDU_FRAG_LEN,extra_space);
 233
 234                 if((new_data = malloc(new_size)) == NULL) {
 235                         DEBUG(0,("prs_grow: Malloc failure for size %u.\n", (unsigned int)new_size));
 236                         return False;
 237                 }
 238                 memset(new_data, '\0', new_size );
 239         } else {
 240                 /*
 241                  * If the current buffer size is bigger than the space needed, just
 242                  * double it, else add extra_space.
 243                  */
 244                 new_size = MAX(ps->buffer_size*2, ps->buffer_size + extra_space);
 245
 246                 if ((new_data = Realloc(ps->data_p, new_size)) == NULL) {
 247                         DEBUG(0,("prs_grow: Realloc failure for size %u.\n",
 248                                 (unsigned int)new_size));
 249                         return False;
 250                 }
 251
 252                 memset(&new_data[ps->buffer_size], '\0', new_size - ps->buffer_size);
 253         }
 254         ps->buffer_size = new_size;
 255         ps->data_p = new_data;
 256
 257         return True;
 258 }
 259
 260 /*******************************************************************
 261  Attempt to force a data buffer to grow by len bytes.
 262  This is only used when appending more data onto a prs_struct
 263  when reading an rpc reply, before unmarshalling it.
 264  ********************************************************************/
 265
 266 BOOL prs_force_grow(prs_struct *ps, uint32 extra_space)
 267 {
 268         uint32 new_size = ps->buffer_size + extra_space;
 269         char *new_data;
 270
 271         if(!UNMARSHALLING(ps) || !ps->is_dynamic) {
 272                 DEBUG(0,("prs_force_grow: Buffer overflow - unable to expand buffer by %u bytes.\n",
 273                                 (unsigned int)extra_space));
 274                 return False;
 275         }
 276
 277         if((new_data = Realloc(ps->data_p, new_size)) == NULL) {
 278                 DEBUG(0,("prs_force_grow: Realloc failure for size %u.\n",
 279                         (unsigned int)new_size));
 280                 return False;
 281         }
 282
 283         memset(&new_data[ps->buffer_size], '\0', new_size - ps->buffer_size);
 284
 285         ps->buffer_size = new_size;
 286         ps->data_p = new_data;
 287
 288         return True;
 289 }
 290
 291 /*******************************************************************
 292  Get the data pointer (external interface).
 293  ********************************************************************/
 294
 295 char *prs_data_p(prs_struct *ps)
 296 {
 297         return ps->data_p;
 298 }
 299
 300 /*******************************************************************
 301  Get the current data size (external interface).
 302  ********************************************************************/
 303
 304 uint32 prs_data_size(prs_struct *ps)
 305 {
 306         return ps->buffer_size;
 307 }
 308
 309 /*******************************************************************
 310  Fetch the current offset (external interface).
 311  ********************************************************************/
 312
 313 uint32 prs_offset(prs_struct *ps)
 314 {
 315         return ps->data_offset;
 316 }
 317
 318 /*******************************************************************
 319  Set the current offset (external interface).
 320  ********************************************************************/
 321
 322 BOOL prs_set_offset(prs_struct *ps, uint32 offset)
 323 {
 324         if(offset <= ps->data_offset) {
 325                 ps->data_offset = offset;
 326                 return True;
 327         }
 328
 329         if(!prs_grow(ps, offset - ps->data_offset))
 330                 return False;
 331
 332         ps->data_offset = offset;
 333         return True;
 334 }
 335
 336 /*******************************************************************
 337  Append the data from one parse_struct into another.
 338  ********************************************************************/
 339
 340 BOOL prs_append_prs_data(prs_struct *dst, prs_struct *src)
 341 {
 342         if(!prs_grow(dst, prs_offset(src)))
 343                 return False;
 344
 345         memcpy(&dst->data_p[dst->data_offset], prs_data_p(src), (size_t)prs_offset(src));
 346         dst->data_offset += prs_offset(src);
 347
 348         return True;
 349 }
 350
 351 /*******************************************************************
 352  Append some data from one parse_struct into another.
 353  ********************************************************************/
 354
 355 BOOL prs_append_some_prs_data(prs_struct *dst, prs_struct *src, int32 start, uint32 len)
 356 {
 357         if (len == 0)
 358                 return True;
 359
 360         if(!prs_grow(dst, len))
 361                 return False;
 362
 363         memcpy(&dst->data_p[dst->data_offset], prs_data_p(src)+start, (size_t)len);
 364         dst->data_offset += len;
 365
 366         return True;
 367 }
 368
 369 /*******************************************************************
 370  Append the data from a buffer into a parse_struct.
 371  ********************************************************************/
 372
 373 BOOL prs_append_data(prs_struct *dst, char *src, uint32 len)
 374 {
 375         if(!prs_grow(dst, len))
 376                 return False;
 377
 378         memcpy(&dst->data_p[dst->data_offset], src, (size_t)len);
 379         dst->data_offset += len;
 380
 381         return True;
 382 }
 383
 384 /*******************************************************************
 385  Set the data as big-endian (external interface).
 386  ********************************************************************/
 387
 388 void prs_set_bigendian_data(prs_struct *ps)
 389 {
 390         ps->bigendian_data = True;
 391 }
 392
 393 /*******************************************************************
 394  Align a the data_len to a multiple of align bytes - filling with
 395  zeros.
 396  ********************************************************************/
 397
 398 BOOL prs_align(prs_struct *ps)
 399 {
 400         uint32 mod = ps->data_offset & (ps->align-1);
 401
 402         if (ps->align != 0 && mod != 0) {
 403                 uint32 extra_space = (ps->align - mod);
 404                 if(!prs_grow(ps, extra_space))
 405                         return False;
 406                 memset(&ps->data_p[ps->data_offset], '\0', (size_t)extra_space);
 407                 ps->data_offset += extra_space;
 408         }
 409
 410         return True;
 411 }
 412
 413 /*******************************************************************
 414  Ensure we can read/write to a given offset.
 415  ********************************************************************/
 416
 417 char *prs_mem_get(prs_struct *ps, uint32 extra_size)
 418 {
 419         if(UNMARSHALLING(ps)) {
 420                 /*
 421                  * If reading, ensure that we can read the requested size item.
 422                  */
 423                 if (ps->data_offset + extra_size > ps->buffer_size) {
 424                         DEBUG(0,("prs_mem_get: reading data of size %u would overrun buffer.\n",
 425                                         (unsigned int)extra_size ));
 426                         return NULL;
 427                 }
 428         } else {
 429                 /*
 430                  * Writing - grow the buffer if needed.
 431                  */
 432                 if(!prs_grow(ps, extra_size))
 433                         return False;
 434         }
 435         return &ps->data_p[ps->data_offset];
 436 }
 437
 438 /*******************************************************************
 439  Change the struct type.
 440  ********************************************************************/
 441
 442 void prs_switch_type(prs_struct *ps, BOOL io)
 443 {
 444         if ((ps->io ^ io) == True)
 445                 ps->io=io;
 446 }
 447
 448 /*******************************************************************
 449  Force a prs_struct to be dynamic even when it's size is 0.
 450  ********************************************************************/
 451
 452 void prs_force_dynamic(prs_struct *ps)
 453 {
 454         ps->is_dynamic=True;
 455 }
 456
 457 /*******************************************************************
 458  Stream a uint8.
 459  ********************************************************************/
 460
 461 BOOL prs_uint8(char *name, prs_struct *ps, int depth, uint8 *data8)
 462 {
 463         char *q = prs_mem_get(ps, sizeof(uint8));
 464         if (q == NULL)
 465                 return False;
 466
 467         DBG_RW_CVAL(name, depth, ps->data_offset, ps->io, q, *data8)
 468         ps->data_offset += sizeof(uint8);
 469
 470         return True;
 471 }
 472
 473 /*******************************************************************
 474  Stream a uint16.
 475  ********************************************************************/
 476
 477 BOOL prs_uint16(char *name, prs_struct *ps, int depth, uint16 *data16)
 478 {
 479         char *q = prs_mem_get(ps, sizeof(uint16));
 480         if (q == NULL)
 481                 return False;
 482
 483         DBG_RW_SVAL(name, depth, ps->data_offset, ps->io, ps->bigendian_data, q, *data16)
 484         ps->data_offset += sizeof(uint16);
 485
 486         return True;
 487 }
 488
 489 /*******************************************************************
 490  Stream a uint32.
 491  ********************************************************************/
 492
 493 BOOL prs_uint32(char *name, prs_struct *ps, int depth, uint32 *data32)
 494 {
 495         char *q = prs_mem_get(ps, sizeof(uint32));
 496         if (q == NULL)
 497                 return False;
 498
 499         DBG_RW_IVAL(name, depth, ps->data_offset, ps->io, ps->bigendian_data, q, *data32)
 500         ps->data_offset += sizeof(uint32);
 501
 502         return True;
 503 }
 504
 505 /******************************************************************
 506  Stream an array of uint8s. Length is number of uint8s.
 507  ********************************************************************/
 508
 509 BOOL prs_uint8s(BOOL charmode, char *name, prs_struct *ps, int depth, uint8 *data8s, int len)
 510 {
 511         char *q = prs_mem_get(ps, len * sizeof(uint8));
 512         if (q == NULL)
 513                 return False;
 514
 515         DBG_RW_PCVAL(charmode, name, depth, ps->data_offset, ps->io, q, data8s, len)
 516         ps->data_offset += (len * sizeof(uint8));
 517
 518         return True;
 519 }
 520
 521 /******************************************************************
 522  Stream an array of uint16s. Length is number of uint16s.
 523  ********************************************************************/
 524
 525 BOOL prs_uint16s(BOOL charmode, char *name, prs_struct *ps, int depth, uint16 *data16s, int len)
 526 {
 527         char *q = prs_mem_get(ps, len * sizeof(uint16));
 528         if (q == NULL)
 529                 return False;
 530
 531         DBG_RW_PSVAL(charmode, name, depth, ps->data_offset, ps->io, ps->bigendian_data, q, data16s, len)
 532         ps->data_offset += (len * sizeof(uint16));
 533
 534         return True;
 535 }
 536
 537 /******************************************************************
 538  Stream an array of uint32s. Length is number of uint32s.
 539  ********************************************************************/
 540
 541 BOOL prs_uint32s(BOOL charmode, char *name, prs_struct *ps, int depth, uint32 *data32s, int len)
 542 {
 543         char *q = prs_mem_get(ps, len * sizeof(uint32));
 544         if (q == NULL)
 545                 return False;
 546
 547         DBG_RW_PIVAL(charmode, name, depth, ps->data_offset, ps->io, ps->bigendian_data, q, data32s, len)
 548         ps->data_offset += (len * sizeof(uint32));
 549
 550         return True;
 551 }
 552
 553 /******************************************************************
 554  Stream a "not" unicode string, length/buffer specified separately,
 555  in byte chars. String is in little-endian format.
 556  ********************************************************************/
 557
 558 BOOL prs_buffer2(BOOL charmode, char *name, prs_struct *ps, int depth, BUFFER2 *str)
 559 {
 560         char *p;
 561         char *q = prs_mem_get(ps, str->buf_len);
 562         if (q == NULL)
 563                 return False;
 564
 565         if (UNMARSHALLING(ps)) {
 566                 str->buffer = (uint16 *)prs_alloc_mem(ps,str->buf_len);
 567                 if (str->buffer == NULL)
 568                         return False;
 569         }
 570
 571         p = (char *)str->buffer;
 572
 573         /* If we're using big-endian, reverse to get little-endian. */
 574         if(ps->bigendian_data)
 575                 DBG_RW_PSVAL(charmode, name, depth, ps->data_offset, ps->io, ps->bigendian_data, q, p, str->buf_len/2)
 576         else
 577                 DBG_RW_PCVAL(charmode, name, depth, ps->data_offset, ps->io, q, p, str->buf_len)
 578         ps->data_offset += str->buf_len;
 579
 580         return True;
 581 }
 582
 583 /******************************************************************
 584  Stream a string, length/buffer specified separately,
 585  in uint8 chars.
 586  ********************************************************************/
 587
 588 BOOL prs_string2(BOOL charmode, char *name, prs_struct *ps, int depth, STRING2 *str)
 589 {
 590         char *q = prs_mem_get(ps, str->str_str_len * sizeof(uint8));
 591         if (q == NULL)
 592                 return False;
 593
 594         if (UNMARSHALLING(ps)) {
 595                 str->buffer = (unsigned char *)prs_alloc_mem(ps,str->str_str_len);
 596                 if (str->buffer == NULL)
 597                         return False;
 598         }
 599
 600         DBG_RW_PCVAL(charmode, name, depth, ps->data_offset, ps->io, q, str->buffer, str->str_max_len)
 601         ps->data_offset += (str->str_str_len * sizeof(uint8));
 602
 603         return True;
 604 }
 605
 606 /******************************************************************
 607  Stream a unicode string, length/buffer specified separately,
 608  in uint16 chars. We use DBG_RW_PCVAL, not DBG_RW_PSVAL here
 609  as the unicode string is already in little-endian format.
 610  ********************************************************************/
 611
 612 BOOL prs_unistr2(BOOL charmode, char *name, prs_struct *ps, int depth, UNISTR2 *str)
 613 {
 614         char *p;
 615         char *q = prs_mem_get(ps, str->uni_str_len * sizeof(uint16));
 616         if (q == NULL)
 617                 return False;
 618
 619         if (UNMARSHALLING(ps)) {
 620                 str->buffer = (uint16 *)prs_alloc_mem(ps,str->uni_max_len * sizeof(uint16));
 621                 if (str->buffer == NULL)
 622                         return False;
 623                 memset(str->buffer, '\0', str->uni_max_len * sizeof(uint16));
 624         }
 625
 626         /* If the string is empty, we don't have anything to stream */
 627         if (str->uni_str_len==0)
 628                 return True;
 629
 630         p = (char *)str->buffer;
 631
 632         /* If we're using big-endian, reverse to get little-endian. */
 633         if(ps->bigendian_data) {
 634                 DBG_RW_PSVAL(charmode, name, depth, ps->data_offset,
 635                              ps->io, ps->bigendian_data, q, p,
 636                              str->uni_str_len)
 637         } else {
 638                 DBG_RW_PCVAL(charmode, name, depth, ps->data_offset,
 639                              ps->io, q, p, str->uni_str_len * sizeof(uint16))
 640         }
 641
 642         ps->data_offset += (str->uni_str_len * sizeof(uint16));
 643
 644         return True;
 645 }
 646
 647
 648
 649 /******************************************************************
 650  Stream a unicode string, length/buffer specified separately,
 651  in uint16 chars. We use DBG_RW_PCVAL, not DBG_RW_PSVAL here
 652  as the unicode string is already in little-endian format.
 653  ********************************************************************/
 654
 655 BOOL prs_unistr3(BOOL charmode, char *name, UNISTR3 *str, prs_struct *ps, int depth)
 656 {
 657         char *p;
 658         char *q = prs_mem_get(ps, str->uni_str_len * sizeof(uint16));
 659         if (q == NULL)
 660                 return False;
 661
 662         if (UNMARSHALLING(ps)) {
 663                 str->str.buffer = (uint16 *)prs_alloc_mem(ps,str->uni_str_len * sizeof(uint16));
 664                 if (str->str.buffer == NULL)
 665                         return False;
 666         }
 667
 668         p = (char *)str->str.buffer;
 669
 670         /* If we're using big-endian, reverse to get little-endian. */
 671         if(ps->bigendian_data)
 672                 DBG_RW_PSVAL(charmode, name, depth, ps->data_offset, ps->io, ps->bigendian_data, q, p, str->uni_str_len)
 673         else
 674                 DBG_RW_PCVAL(charmode, name, depth, ps->data_offset, ps->io, q, p, str->uni_str_len * sizeof(uint16))
 675         ps->data_offset += (str->uni_str_len * sizeof(uint16));
 676
 677         return True;
 678 }
 679
 680 /*******************************************************************
 681  Stream a unicode  null-terminated string. As the string is already
 682  in little-endian format then do it as a stream of bytes.
 683  ********************************************************************/
 684
 685 BOOL prs_unistr(char *name, prs_struct *ps, int depth, UNISTR *str)
 686 {
 687         int len = 0;
 688         unsigned char *p = (unsigned char *)str->buffer;
 689         uint8 *start;
 690         char *q;
 691         char zero=0;
 692         uint32 max_len;
 693         uint16* ptr;
 694
 695         if (MARSHALLING(ps)) {
 696
 697                 for(len = 0; str->buffer[len] != 0; len++)
 698                         ;
 699
 700                 q = prs_mem_get(ps, (len+1)*2);
 701                 if (q == NULL)
 702                         return False;
 703
 704                 start = (uint8*)q;
 705
 706                 for(len = 0; str->buffer[len] != 0; len++)
 707                 {
 708                         if(ps->bigendian_data)
 709                         {
 710                                 RW_SVAL(ps->io, ps->bigendian_data, q, *p, 0);
 711                                 p += 2;
 712                                 q += 2;
 713                         }
 714                         else
 715                         {
 716                                 RW_CVAL(ps->io, q, *p, 0);
 717                                 p++;
 718                                 q++;
 719                                 RW_CVAL(ps->io, q, *p, 0);
 720                                 p++;
 721                                 q++;
 722                         }
 723                 }
 724
 725                 /*
 726                  * even if the string is 'empty' (only an \0 char)
 727                  * at this point the leading \0 hasn't been parsed.
 728                  * so parse it now
 729                  */
 730
 731                 RW_CVAL(ps->io, q, zero, 0);
 732                 q++;
 733                 RW_CVAL(ps->io, q, zero, 0);
 734                 q++;
 735
 736                 len++;
 737
 738                 dump_data(5+depth, (char *)start, len * 2);
 739         }
 740         else { /* unmarshalling */
 741
 742                 uint32 alloc_len = 0;
 743                 q = prs_data_p(ps) + prs_offset(ps);
 744
 745                 /*
 746                  * Work out how much space we need and talloc it.
 747                  */
 748                 max_len = (ps->buffer_size - ps->data_offset)/sizeof(uint16);
 749
 750                 /* the test of the value of *ptr helps to catch the circumstance
 751                    where we have an emtpty (non-existent) string in the buffer */
 752                 for ( ptr = (uint16 *)q; *ptr && (alloc_len <= max_len); alloc_len++)
 753                         /* do nothing */
 754                         ;
 755
 756                 /* should we allocate anything at all? */
 757                 str->buffer = (uint16 *)prs_alloc_mem(ps,alloc_len * sizeof(uint16));
 758                 if ((str->buffer == NULL) && (alloc_len > 0))
 759                         return False;
 760
 761                 p = (unsigned char *)str->buffer;
 762
 763                 len = 0;
 764                 /* the (len < alloc_len) test is to prevent us from overwriting
 765                    memory that is not ours...if we get that far, we have a non-null
 766                    terminated string in the buffer and have messed up somewhere */
 767                 while ((len < alloc_len) && (*q != '\0'))
 768                 {
 769                         if(ps->bigendian_data)
 770                         {
 771                                 RW_SVAL(ps->io, ps->bigendian_data, q, *p, 0);
 772                                 p += 2;
 773                                 q += 2;
 774                         } else {
 775 #if WORDS_BIGENDIAN
 776                                 RW_CVAL(ps->io, q+1, *p, 0);
 777                                 p++;
 778                                 RW_CVAL(ps->io, q, *p, 0);
 779                                 p++;
 780                                 q+=2;
 781 #else
 782                                 RW_CVAL(ps->io, q, *p, 0);
 783                                 p++;
 784                                 q++;
 785                                 RW_CVAL(ps->io, q, *p, 0);
 786                                 p++;
 787                                 q++;
 788 #endif  /* WORDS_BIGENDIAN */
 789
 790                         }
 791
 792                         len++;
 793                 }
 794                 if (len < alloc_len)
 795                 {
 796                         /* NULL terminate the UNISTR */
 797                         str->buffer[len++] = '\0';
 798                 }
 799         }
 800
 801         /* set the offset in the prs_struct; 'len' points to the
 802            terminiating NULL in the UNISTR so we need to go one more
 803            uint16 */
 804         ps->data_offset += (len)*2;
 805
 806         return True;
 807 }
 808
 809
 810 /*******************************************************************
 811  Stream a null-terminated string.  len is strlen, and therefore does
 812  not include the null-termination character.
 813  ********************************************************************/
 814
 815 BOOL prs_string(char *name, prs_struct *ps, int depth, char *str, int len, int max_buf_size)
 816 {
 817         char *q;
 818         uint8 *start;
 819         int i;
 820
 821         len = MIN(len, (max_buf_size-1));
 822
 823         q = prs_mem_get(ps, len+1);
 824         if (q == NULL)
 825                 return False;
 826
 827         start = (uint8*)q;
 828
 829         for(i = 0; i < len; i++) {
 830                 RW_CVAL(ps->io, q, str[i],0);
 831                 q++;
 832         }
 833
 834         /* The terminating null. */
 835         str[i] = '\0';
 836
 837         if (MARSHALLING(ps)) {
 838                 RW_CVAL(ps->io, q, str[i], 0);
 839         }
 840
 841         ps->data_offset += len+1;
 842
 843         dump_data(5+depth, (char *)start, len);
 844
 845         return True;
 846 }
 847
 848 /*******************************************************************
 849  prs_uint16 wrapper. Call this and it sets up a pointer to where the
 850  uint16 should be stored, or gets the size if reading.
 851  ********************************************************************/
 852
 853 BOOL prs_uint16_pre(char *name, prs_struct *ps, int depth, uint16 *data16, uint32 *offset)
 854 {
 855         *offset = ps->data_offset;
 856         if (UNMARSHALLING(ps)) {
 857                 /* reading. */
 858                 return prs_uint16(name, ps, depth, data16);
 859         } else {
 860                 char *q = prs_mem_get(ps, sizeof(uint16));
 861                 if(q ==NULL)
 862                         return False;
 863                 ps->data_offset += sizeof(uint16);
 864         }
 865         return True;
 866 }
 867
 868 /*******************************************************************
 869  prs_uint16 wrapper.  call this and it retrospectively stores the size.
 870  does nothing on reading, as that is already handled by ...._pre()
 871  ********************************************************************/
 872
 873 BOOL prs_uint16_post(char *name, prs_struct *ps, int depth, uint16 *data16,
 874                                 uint32 ptr_uint16, uint32 start_offset)
 875 {
 876         if (MARSHALLING(ps)) {
 877                 /*
 878                  * Writing - temporarily move the offset pointer.
 879                  */
 880                 uint16 data_size = ps->data_offset - start_offset;
 881                 uint32 old_offset = ps->data_offset;
 882
 883                 ps->data_offset = ptr_uint16;
 884                 if(!prs_uint16(name, ps, depth, &data_size)) {
 885                         ps->data_offset = old_offset;
 886                         return False;
 887                 }
 888                 ps->data_offset = old_offset;
 889         } else {
 890                 ps->data_offset = start_offset + (uint32)(*data16);
 891         }
 892         return True;
 893 }
 894
 895 /*******************************************************************
 896  prs_uint32 wrapper. Call this and it sets up a pointer to where the
 897  uint32 should be stored, or gets the size if reading.
 898  ********************************************************************/
 899
 900 BOOL prs_uint32_pre(char *name, prs_struct *ps, int depth, uint32 *data32, uint32 *offset)
 901 {
 902         *offset = ps->data_offset;
 903         if (UNMARSHALLING(ps) && (data32 != NULL)) {
 904                 /* reading. */
 905                 return prs_uint32(name, ps, depth, data32);
 906         } else {
 907                 ps->data_offset += sizeof(uint32);
 908         }
 909         return True;
 910 }
 911
 912 /*******************************************************************
 913  prs_uint32 wrapper.  call this and it retrospectively stores the size.
 914  does nothing on reading, as that is already handled by ...._pre()
 915  ********************************************************************/
 916
 917 BOOL prs_uint32_post(char *name, prs_struct *ps, int depth, uint32 *data32,
 918                                 uint32 ptr_uint32, uint32 data_size)
 919 {
 920         if (MARSHALLING(ps)) {
 921                 /*
 922                  * Writing - temporarily move the offset pointer.
 923                  */
 924                 uint32 old_offset = ps->data_offset;
 925                 ps->data_offset = ptr_uint32;
 926                 if(!prs_uint32(name, ps, depth, &data_size)) {
 927                         ps->data_offset = old_offset;
 928                         return False;
 929                 }
 930                 ps->data_offset = old_offset;
 931         }
 932         return True;
 933 }
 934
 935 /* useful function to store a structure in rpc wire format */
 936 int tdb_prs_store(TDB_CONTEXT *tdb, char *keystr, prs_struct *ps)
 937 {
 938     TDB_DATA kbuf, dbuf;
 939     kbuf.dptr = keystr;
 940     kbuf.dsize = strlen(keystr)+1;
 941     dbuf.dptr = prs_data_p(ps);
 942     dbuf.dsize = prs_offset(ps);
 943     return tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
 944 }
 945
 946 /* useful function to fetch a structure into rpc wire format */
 947 int tdb_prs_fetch(TDB_CONTEXT *tdb, char *keystr, prs_struct *ps, TALLOC_CTX *mem_ctx)
 948 {
 949     TDB_DATA kbuf, dbuf;
 950     kbuf.dptr = keystr;
 951     kbuf.dsize = strlen(keystr)+1;
 952
 953     dbuf = tdb_fetch(tdb, kbuf);
 954     if (!dbuf.dptr) return -1;
 955
 956     ZERO_STRUCTP(ps);
 957     prs_init(ps, 0, 4, mem_ctx, UNMARSHALL);
 958     prs_give_memory(ps, dbuf.dptr, dbuf.dsize, True);
 959
 960     return 0;
 961 }