source3/lib/ldb/common/ldb_dn.c

   1 /*
   2    ldb database library
   3
   4    Copyright (C) Simo Sorce 2005
   5
   6      ** NOTE! The following LGPL license applies to the ldb
   7      ** library. This does NOT imply that all of Samba is released
   8      ** under the LGPL
   9
  10    This library is free software; you can redistribute it and/or
  11    modify it under the terms of the GNU Lesser General Public
  12    License as published by the Free Software Foundation; either
  13    version 2 of the License, or (at your option) any later version.
  14
  15    This library is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18    Lesser General Public License for more details.
  19
  20    You should have received a copy of the GNU Lesser General Public
  21    License along with this library; if not, write to the Free Software
  22    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23 */
  24
  25 /*
  26  *  Name: ldb
  27  *
  28  *  Component: ldb dn explode and utility functions
  29  *
  30  *  Description: - explode a dn into it's own basic elements
  31  *                 and put them in a structure
  32  *               - manipulate ldb_dn structures
  33  *
  34  *  Author: Simo Sorce
  35  */
  36
  37 #include "includes.h"
  38 #include "ldb/include/includes.h"
  39
  40 #define LDB_DN_NULL_FAILED(x) if (!(x)) goto failed
  41
  42 #define LDB_SPECIAL "@SPECIAL"
  43
  44 int ldb_dn_is_special(const struct ldb_dn *dn)
  45 {
  46         if (dn == NULL || dn->comp_num != 1) return 0;
  47
  48         return ! strcmp(dn->components[0].name, LDB_SPECIAL);
  49 }
  50
  51 int ldb_dn_check_special(const struct ldb_dn *dn, const char *check)
  52 {
  53         if (dn == NULL || dn->comp_num != 1) return 0;
  54
  55         return ! strcmp((char *)dn->components[0].value.data, check);
  56 }
  57
  58 char *ldb_dn_escape_value(void *mem_ctx, struct ldb_val value)
  59 {
  60         const char *p, *s, *src;
  61         char *d, *dst;
  62         int len;
  63
  64         if (!value.length)
  65                 return NULL;
  66
  67         p = s = src = (const char *)value.data;
  68         len = value.length;
  69
  70         /* allocate destination string, it will be at most 3 times the source */
  71         dst = d = talloc_array(mem_ctx, char, len * 3 + 1);
  72         LDB_DN_NULL_FAILED(dst);
  73
  74         while (p - src < len) {
  75
  76                 p += strcspn(p, ",=\n+<>#;\\\"");
  77
  78                 if (p - src == len) /* found no escapable chars */
  79                         break;
  80
  81                 memcpy(d, s, p - s); /* copy the part of the string before the stop */
  82                 d += (p - s); /* move to current position */
  83
  84                 if (*p) { /* it is a normal escapable character */
  85                         *d++ = '\\';
  86                         *d++ = *p++;
  87                 } else { /* we have a zero byte in the string */
  88                         strncpy(d, "\00", 3); /* escape the zero */
  89                         d = d + 3;
  90                         p++; /* skip the zero */
  91                 }
  92                 s = p; /* move forward */
  93         }
  94
  95         /* copy the last part (with zero) and return */
  96         memcpy(d, s, &src[len] - s + 1);
  97
  98         return dst;
  99
 100 failed:
 101         talloc_free(dst);
 102         return NULL;
 103 }
 104
 105 static struct ldb_val ldb_dn_unescape_value(void *mem_ctx, const char *src)
 106 {
 107         struct ldb_val value;
 108         unsigned x;
 109         char *p, *dst = NULL, *end;
 110
 111         memset(&value, 0, sizeof(value));
 112
 113         LDB_DN_NULL_FAILED(src);
 114
 115         dst = p = talloc_memdup(mem_ctx, src, strlen(src) + 1);
 116         LDB_DN_NULL_FAILED(dst);
 117
 118         end = &dst[strlen(dst)];
 119
 120         while (*p) {
 121                 p += strcspn(p, ",=\n+<>#;\\\"");
 122
 123                 if (*p == '\\') {
 124                         if (strchr(",=\n+<>#;\\\"", p[1])) {
 125                                 memmove(p, p + 1, end - (p + 1) + 1);
 126                                 end--;
 127                                 p++;
 128                                 continue;
 129                         }
 130
 131                         if (sscanf(p + 1, "%02x", &x) == 1) {
 132                                 *p = (unsigned char)x;
 133                                 memmove(p + 1, p + 3, end - (p + 3) + 1);
 134                                 end -= 2;
 135                                 p++;
 136                                 continue;
 137                         }
 138                 }
 139
 140                 /* a string with not escaped specials is invalid (tested) */
 141                 if (*p != '\0') {
 142                         goto failed;
 143                 }
 144         }
 145
 146         value.length = end - dst;
 147         value.data = (uint8_t *)dst;
 148         return value;
 149
 150 failed:
 151         talloc_free(dst);
 152         return value;
 153 }
 154
 155 /* check if the string contains quotes
 156  * skips leading and trailing spaces
 157  * - returns 0 if no quotes found
 158  * - returns 1 if quotes are found and put their position
 159  *   in *quote_start and *quote_end parameters
 160  * - return -1 if there are open quotes
 161  */
 162
 163 static int get_quotes_position(const char *source, int *quote_start, int *quote_end)
 164 {
 165         const char *p;
 166
 167         if (source == NULL || quote_start == NULL || quote_end == NULL) return -1;
 168
 169         p = source;
 170
 171         /* check if there are quotes surrounding the value */
 172         p += strspn(p, " \n"); /* skip white spaces */
 173
 174         if (*p == '\"') {
 175                 *quote_start = p - source;
 176
 177                 p++;
 178                 while (*p != '\"') {
 179                         p = strchr(p, '\"');
 180                         LDB_DN_NULL_FAILED(p);
 181
 182                         if (*(p - 1) == '\\')
 183                                 p++;
 184                 }
 185
 186                 *quote_end = p - source;
 187                 return 1;
 188         }
 189
 190         return 0;
 191
 192 failed:
 193         return -1;
 194 }
 195
 196 static char *seek_to_separator(char *string, const char *separators)
 197 {
 198         char *p, *q;
 199         int ret, qs, qe, escaped;
 200
 201         if (string == NULL || separators == NULL) return NULL;
 202
 203         p = strchr(string, '=');
 204         LDB_DN_NULL_FAILED(p);
 205
 206         p++;
 207
 208         /* check if there are quotes surrounding the value */
 209
 210         ret = get_quotes_position(p, &qs, &qe);
 211         if (ret == -1)
 212                 return NULL;
 213
 214         if (ret == 1) { /* quotes found */
 215
 216                 p += qe; /* positioning after quotes */
 217                 p += strspn(p, " \n"); /* skip white spaces after the quote */
 218
 219                 if (strcspn(p, separators) != 0) /* if there are characters between quotes */
 220                         return NULL;        /* and separators, the dn is invalid */
 221
 222                 return p; /* return on the separator */
 223         }
 224
 225         /* no quotes found seek to separators */
 226         q = p;
 227         do {
 228                 escaped = 0;
 229                 ret = strcspn(q, separators);
 230
 231                 if (q[ret - 1] == '\\') {
 232                         escaped = 1;
 233                         q = q + ret + 1;
 234                 }
 235         } while (escaped);
 236
 237         if (ret == 0 && p == q) /* no separators ?! bail out */
 238                 return NULL;
 239
 240         return q + ret;
 241
 242 failed:
 243         return NULL;
 244 }
 245
 246 static char *ldb_dn_trim_string(char *string, const char *edge)
 247 {
 248         char *s, *p;
 249
 250         /* seek out edge from start of string */
 251         s = string + strspn(string, edge);
 252
 253         /* backwards skip from end of string */
 254         p = &s[strlen(s) - 1];
 255         while (p > s && strchr(edge, *p)) {
 256                 *p = '\0';
 257                 p--;
 258         }
 259
 260         return s;
 261 }
 262
 263 /* we choosed to not support multpile valued components */
 264 static struct ldb_dn_component ldb_dn_explode_component(void *mem_ctx, char *raw_component)
 265 {
 266         struct ldb_dn_component dc;
 267         char *p;
 268         int ret, qs, qe;
 269
 270         memset(&dc, 0, sizeof(dc));
 271
 272         if (raw_component == NULL) {
 273                 return dc;
 274         }
 275
 276         /* find attribute type/value separator */
 277         p = strchr(raw_component, '=');
 278         LDB_DN_NULL_FAILED(p);
 279
 280         *p++ = '\0'; /* terminate name and point to value */
 281
 282         /* copy and trim name in the component */
 283         dc.name = talloc_strdup(mem_ctx, ldb_dn_trim_string(raw_component, " \n"));
 284         if (!dc.name)
 285                 return dc;
 286
 287         if (! ldb_valid_attr_name(dc.name)) {
 288                 goto failed;
 289         }
 290
 291         ret = get_quotes_position(p, &qs, &qe);
 292
 293         switch (ret) {
 294         case 0: /* no quotes trim the string */
 295                 p = ldb_dn_trim_string(p, " \n");
 296                 dc.value = ldb_dn_unescape_value(mem_ctx, p);
 297                 break;
 298
 299         case 1: /* quotes found get the unquoted string */
 300                 p[qe] = '\0';
 301                 p = p + qs + 1;
 302                 dc.value.length = strlen(p);
 303                 dc.value.data = talloc_memdup(mem_ctx, p, dc.value.length + 1);
 304                 break;
 305
 306         default: /* mismatched quotes ot other error, bail out */
 307                 goto failed;
 308         }
 309
 310         if (dc.value.length == 0) {
 311                 goto failed;
 312         }
 313
 314         return dc;
 315
 316 failed:
 317         talloc_free(dc.name);
 318         dc.name = NULL;
 319         return dc;
 320 }
 321
 322 struct ldb_dn *ldb_dn_new(void *mem_ctx)
 323 {
 324         struct ldb_dn *edn;
 325
 326         edn = talloc(mem_ctx, struct ldb_dn);
 327         LDB_DN_NULL_FAILED(edn);
 328
 329         /* Initially there are no components */
 330         edn->comp_num = 0;
 331         edn->components = NULL;
 332
 333         return edn;
 334
 335 failed:
 336         return NULL;
 337 }
 338
 339 struct ldb_dn *ldb_dn_explode(void *mem_ctx, const char *dn)
 340 {
 341         struct ldb_dn *edn; /* the exploded dn */
 342         char *pdn, *p;
 343
 344         if (dn == NULL) return NULL;
 345
 346         /* Allocate a structure to hold the exploded DN */
 347         edn = ldb_dn_new(mem_ctx);
 348         pdn = NULL;
 349
 350         /* Empty DNs */
 351         if (dn[0] == '\0') {
 352                 return edn;
 353         }
 354
 355         /* Special DNs case */
 356         if (dn[0] == '@') {
 357                 edn->comp_num = 1;
 358                 edn->components = talloc(edn, struct ldb_dn_component);
 359                 if (edn->components == NULL) goto failed;
 360                 edn->components[0].name = talloc_strdup(edn->components, LDB_SPECIAL);
 361                 if (edn->components[0].name == NULL) goto failed;
 362                 edn->components[0].value.data = (uint8_t *)talloc_strdup(edn->components, dn);
 363                 if (edn->components[0].value.data== NULL) goto failed;
 364                 edn->components[0].value.length = strlen(dn);
 365                 return edn;
 366         }
 367
 368         pdn = p = talloc_strdup(edn, dn);
 369         LDB_DN_NULL_FAILED(pdn);
 370
 371         /* get the components */
 372         do {
 373                 char *t;
 374
 375                 /* terminate the current component and return pointer to the next one */
 376                 t = seek_to_separator(p, ",;");
 377                 LDB_DN_NULL_FAILED(t);
 378
 379                 if (*t) { /* here there is a separator */
 380                         *t = '\0'; /*terminate */
 381                         t++; /* a separtor means another component follows */
 382                 }
 383
 384                 /* allocate space to hold the dn component */
 385                 edn->components = talloc_realloc(edn, edn->components,
 386                                                  struct ldb_dn_component,
 387                                                  edn->comp_num + 1);
 388                 if (edn->components == NULL)
 389                         goto failed;
 390
 391                 /* store the exploded component in the main structure */
 392                 edn->components[edn->comp_num] = ldb_dn_explode_component(edn, p);
 393                 LDB_DN_NULL_FAILED(edn->components[edn->comp_num].name);
 394
 395                 edn->comp_num++;
 396
 397                 /* jump to the next component if any */
 398                 p = t;
 399
 400         } while(*p);
 401
 402         talloc_free(pdn);
 403         return edn;
 404
 405 failed:
 406         talloc_free(pdn);
 407         talloc_free(edn);
 408         return NULL;
 409 }
 410
 411 struct ldb_dn *ldb_dn_explode_or_special(void *mem_ctx, const char *dn)
 412 {
 413         struct ldb_dn *edn; /* the exploded dn */
 414
 415         if (dn == NULL) return NULL;
 416
 417         if (strncasecmp(dn, "<GUID=", 6) == 0) {
 418                 /* this is special DN returned when the
 419                  * exploded_dn control is used
 420                  */
 421
 422                 /* Allocate a structure to hold the exploded DN */
 423                 edn = ldb_dn_new(mem_ctx);
 424
 425                 edn->comp_num = 1;
 426                 edn->components = talloc(edn, struct ldb_dn_component);
 427                 if (edn->components == NULL) goto failed;
 428                 edn->components[0].name = talloc_strdup(edn->components, LDB_SPECIAL);
 429                 if (edn->components[0].name == NULL) goto failed;
 430                 edn->components[0].value.data = (uint8_t *)talloc_strdup(edn->components, dn);
 431                 if (edn->components[0].value.data== NULL) goto failed;
 432                 edn->components[0].value.length = strlen(dn);
 433                 return edn;
 434
 435         }
 436
 437         return ldb_dn_explode(mem_ctx, dn);
 438
 439 failed:
 440         talloc_free(edn);
 441         return NULL;
 442 }
 443
 444 char *ldb_dn_linearize(void *mem_ctx, const struct ldb_dn *edn)
 445 {
 446         char *dn, *value;
 447         int i;
 448
 449         if (edn == NULL) return NULL;
 450
 451         /* Special DNs */
 452         if (ldb_dn_is_special(edn)) {
 453                 dn = talloc_strdup(mem_ctx, (char *)edn->components[0].value.data);
 454                 return dn;
 455         }
 456
 457         dn = talloc_strdup(mem_ctx, "");
 458         LDB_DN_NULL_FAILED(dn);
 459
 460         for (i = 0; i < edn->comp_num; i++) {
 461                 value = ldb_dn_escape_value(dn, edn->components[i].value);
 462                 LDB_DN_NULL_FAILED(value);
 463
 464                 if (i == 0) {
 465                         dn = talloc_asprintf_append(dn, "%s=%s", edn->components[i].name, value);
 466                 } else {
 467                         dn = talloc_asprintf_append(dn, ",%s=%s", edn->components[i].name, value);
 468                 }
 469                 LDB_DN_NULL_FAILED(dn);
 470
 471                 talloc_free(value);
 472         }
 473
 474         return dn;
 475
 476 failed:
 477         talloc_free(dn);
 478         return NULL;
 479 }
 480
 481 /* Determine if dn is below base, in the ldap tree.  Used for
 482  * evaluating a subtree search.
 483  * 0 if they match, otherwise non-zero
 484  */
 485
 486 int ldb_dn_compare_base(struct ldb_context *ldb,
 487                         const struct ldb_dn *base,
 488                         const struct ldb_dn *dn)
 489 {
 490         int ret;
 491         int n0, n1;
 492
 493         if (base == NULL || base->comp_num == 0) return 0;
 494         if (dn == NULL || dn->comp_num == 0) return -1;
 495
 496         /* if the base has more componts than the dn, then they differ */
 497         if (base->comp_num > dn->comp_num) {
 498                 return (dn->comp_num - base->comp_num);
 499         }
 500
 501         n0 = base->comp_num - 1;
 502         n1 = dn->comp_num - 1;
 503         while (n0 >= 0 && n1 >= 0) {
 504                 const struct ldb_attrib_handler *h;
 505
 506                 /* compare names (attribute names are guaranteed to be ASCII only) */
 507                 ret = ldb_attr_cmp(base->components[n0].name,
 508                                    dn->components[n1].name);
 509                 if (ret) {
 510                         return ret;
 511                 }
 512
 513                 /* names match, compare values */
 514                 h = ldb_attrib_handler(ldb, base->components[n0].name);
 515                 ret = h->comparison_fn(ldb, ldb, &(base->components[n0].value),
 516                                                   &(dn->components[n1].value));
 517                 if (ret) {
 518                         return ret;
 519                 }
 520                 n1--;
 521                 n0--;
 522         }
 523
 524         return 0;
 525 }
 526
 527 /* compare DNs using casefolding compare functions.
 528
 529    If they match, then return 0
 530  */
 531
 532 int ldb_dn_compare(struct ldb_context *ldb,
 533                    const struct ldb_dn *edn0,
 534                    const struct ldb_dn *edn1)
 535 {
 536         if (edn0 == NULL || edn1 == NULL) return edn1 - edn0;
 537
 538         if (edn0->comp_num != edn1->comp_num)
 539                 return (edn1->comp_num - edn0->comp_num);
 540
 541         return ldb_dn_compare_base(ldb, edn0, edn1);
 542 }
 543
 544 int ldb_dn_cmp(struct ldb_context *ldb, const char *dn0, const char *dn1)
 545 {
 546         struct ldb_dn *edn0;
 547         struct ldb_dn *edn1;
 548         int ret;
 549
 550         if (dn0 == NULL || dn1 == NULL) return dn1 - dn0;
 551
 552         edn0 = ldb_dn_explode_casefold(ldb, dn0);
 553         if (edn0 == NULL) return 1;
 554
 555         edn1 = ldb_dn_explode_casefold(ldb, dn1);
 556         if (edn1 == NULL) {
 557                 talloc_free(edn0);
 558                 return -1;
 559         }
 560
 561         ret = ldb_dn_compare(ldb, edn0, edn1);
 562
 563         talloc_free(edn0);
 564         talloc_free(edn1);
 565
 566         return ret;
 567 }
 568
 569 /*
 570   casefold a dn. We need to casefold the attribute names, and canonicalize
 571   attribute values of case insensitive attributes.
 572 */
 573 struct ldb_dn *ldb_dn_casefold(struct ldb_context *ldb, const struct ldb_dn *edn)
 574 {
 575         struct ldb_dn *cedn;
 576         int i;
 577
 578         if (edn == NULL) return NULL;
 579
 580         cedn = ldb_dn_new(ldb);
 581         if (!cedn) {
 582                 return NULL;
 583         }
 584
 585         cedn->comp_num = edn->comp_num;
 586         cedn->components = talloc_array(cedn, struct ldb_dn_component, edn->comp_num);
 587         if (!cedn->components) {
 588                 talloc_free(cedn);
 589                 return NULL;
 590         }
 591
 592         for (i = 0; i < edn->comp_num; i++) {
 593                 struct ldb_dn_component dc;
 594                 const struct ldb_attrib_handler *h;
 595
 596                 dc.name = ldb_attr_casefold(cedn, edn->components[i].name);
 597                 if (!dc.name) {
 598                         talloc_free(cedn);
 599                         return NULL;
 600                 }
 601
 602                 h = ldb_attrib_handler(ldb, dc.name);
 603                 if (h->canonicalise_fn(ldb, cedn, &(edn->components[i].value), &(dc.value)) != 0) {
 604                         talloc_free(cedn);
 605                         return NULL;
 606                 }
 607
 608                 cedn->components[i] = dc;
 609         }
 610
 611         return cedn;
 612 }
 613
 614 struct ldb_dn *ldb_dn_explode_casefold(struct ldb_context *ldb, const char *dn)
 615 {
 616         struct ldb_dn *edn, *cdn;
 617
 618         if (dn == NULL) return NULL;
 619
 620         edn = ldb_dn_explode(ldb, dn);
 621         if (edn == NULL) return NULL;
 622
 623         cdn = ldb_dn_casefold(ldb, edn);
 624
 625         talloc_free(edn);
 626         return cdn;
 627 }
 628
 629 char *ldb_dn_linearize_casefold(struct ldb_context *ldb, const struct ldb_dn *edn)
 630 {
 631         struct ldb_dn *cdn;
 632         char *dn;
 633
 634         if (edn == NULL) return NULL;
 635
 636         /* Special DNs */
 637         if (ldb_dn_is_special(edn)) {
 638                 dn = talloc_strdup(ldb, (char *)edn->components[0].value.data);
 639                 return dn;
 640         }
 641
 642         cdn = ldb_dn_casefold(ldb, edn);
 643         if (cdn == NULL) return NULL;
 644
 645         dn = ldb_dn_linearize(ldb, cdn);
 646         if (dn == NULL) {
 647                 talloc_free(cdn);
 648                 return NULL;
 649         }
 650
 651         talloc_free(cdn);
 652         return dn;
 653 }
 654
 655 static struct ldb_dn_component ldb_dn_copy_component(void *mem_ctx, struct ldb_dn_component *src)
 656 {
 657         struct ldb_dn_component dst;
 658
 659         memset(&dst, 0, sizeof(dst));
 660
 661         if (src == NULL) {
 662                 return dst;
 663         }
 664
 665         dst.value = ldb_val_dup(mem_ctx, &(src->value));
 666         if (dst.value.data == NULL) {
 667                 return dst;
 668         }
 669
 670         dst.name = talloc_strdup(mem_ctx, src->name);
 671         if (dst.name == NULL) {
 672                 talloc_free(dst.value.data);
 673         }
 674
 675         return dst;
 676 }
 677
 678 /* copy specified number of elements of a dn into a new one
 679    element are copied from top level up to the unique rdn
 680    num_el may be greater than dn->comp_num (see ldb_dn_make_child)
 681 */
 682 struct ldb_dn *ldb_dn_copy_partial(void *mem_ctx, const struct ldb_dn *dn, int num_el)
 683 {
 684         struct ldb_dn *newdn;
 685         int i, n, e;
 686
 687         if (dn == NULL) return NULL;
 688         if (num_el <= 0) return NULL;
 689
 690         newdn = ldb_dn_new(mem_ctx);
 691         LDB_DN_NULL_FAILED(newdn);
 692
 693         newdn->comp_num = num_el;
 694         n = newdn->comp_num - 1;
 695         newdn->components = talloc_array(newdn, struct ldb_dn_component, newdn->comp_num);
 696
 697         if (dn->comp_num == 0) return newdn;
 698         e = dn->comp_num - 1;
 699
 700         for (i = 0; i < newdn->comp_num; i++) {
 701                 newdn->components[n - i] = ldb_dn_copy_component(newdn->components,
 702                                                                 &(dn->components[e - i]));
 703                 if ((e - i) == 0) {
 704                         return newdn;
 705                 }
 706         }
 707
 708         return newdn;
 709
 710 failed:
 711         talloc_free(newdn);
 712         return NULL;
 713 }
 714
 715 struct ldb_dn *ldb_dn_copy(void *mem_ctx, const struct ldb_dn *dn)
 716 {
 717         if (dn == NULL) return NULL;
 718         return ldb_dn_copy_partial(mem_ctx, dn, dn->comp_num);
 719 }
 720
 721 struct ldb_dn *ldb_dn_get_parent(void *mem_ctx, const struct ldb_dn *dn)
 722 {
 723         if (dn == NULL) return NULL;
 724         return ldb_dn_copy_partial(mem_ctx, dn, dn->comp_num - 1);
 725 }
 726
 727 struct ldb_dn_component *ldb_dn_build_component(void *mem_ctx, const char *attr,
 728                                                 const char *val)
 729 {
 730         struct ldb_dn_component *dc;
 731
 732         if (attr == NULL || val == NULL) return NULL;
 733
 734         dc = talloc(mem_ctx, struct ldb_dn_component);
 735         if (dc == NULL) return NULL;
 736
 737         dc->name = talloc_strdup(dc, attr);
 738         if (dc->name ==  NULL) {
 739                 talloc_free(dc);
 740                 return NULL;
 741         }
 742
 743         dc->value.data = (uint8_t *)talloc_strdup(dc, val);
 744         if (dc->value.data ==  NULL) {
 745                 talloc_free(dc);
 746                 return NULL;
 747         }
 748
 749         dc->value.length = strlen(val);
 750
 751         return dc;
 752 }
 753
 754 struct ldb_dn *ldb_dn_build_child(void *mem_ctx, const char *attr,
 755                                                  const char * value,
 756                                                  const struct ldb_dn *base)
 757 {
 758         struct ldb_dn *newdn;
 759         if (! ldb_valid_attr_name(attr)) return NULL;
 760         if (value == NULL || value == '\0') return NULL;
 761
 762         if (base != NULL) {
 763                 newdn = ldb_dn_copy_partial(mem_ctx, base, base->comp_num + 1);
 764                 LDB_DN_NULL_FAILED(newdn);
 765         } else {
 766                 newdn = ldb_dn_new(mem_ctx);
 767                 LDB_DN_NULL_FAILED(newdn);
 768
 769                 newdn->comp_num = 1;
 770                 newdn->components = talloc_array(newdn, struct ldb_dn_component, newdn->comp_num);
 771         }
 772
 773         newdn->components[0].name = talloc_strdup(newdn->components, attr);
 774         LDB_DN_NULL_FAILED(newdn->components[0].name);
 775
 776         newdn->components[0].value.data = (uint8_t *)talloc_strdup(newdn->components, value);
 777         LDB_DN_NULL_FAILED(newdn->components[0].value.data);
 778         newdn->components[0].value.length = strlen((char *)newdn->components[0].value.data);
 779
 780         return newdn;
 781
 782 failed:
 783         talloc_free(newdn);
 784         return NULL;
 785
 786 }
 787
 788 struct ldb_dn *ldb_dn_make_child(void *mem_ctx, const struct ldb_dn_component *component,
 789                                                 const struct ldb_dn *base)
 790 {
 791         if (component == NULL) return NULL;
 792
 793         return ldb_dn_build_child(mem_ctx, component->name,
 794                                   (char *)component->value.data, base);
 795 }
 796
 797 struct ldb_dn *ldb_dn_compose(void *mem_ctx, const struct ldb_dn *dn1, const struct ldb_dn *dn2)
 798 {
 799         int i;
 800         struct ldb_dn *newdn;
 801
 802         if (dn2 == NULL && dn1 == NULL) {
 803                 return NULL;
 804         }
 805
 806         if (dn2 == NULL) {
 807                 newdn = ldb_dn_new(mem_ctx);
 808                 LDB_DN_NULL_FAILED(newdn);
 809
 810                 newdn->comp_num = dn1->comp_num;
 811                 newdn->components = talloc_array(newdn, struct ldb_dn_component, newdn->comp_num);
 812         } else {
 813                 int comp_num = dn2->comp_num;
 814                 if (dn1 != NULL) comp_num += dn1->comp_num;
 815                 newdn = ldb_dn_copy_partial(mem_ctx, dn2, comp_num);
 816         }
 817
 818         if (dn1 == NULL) {
 819                 return newdn;
 820         }
 821
 822         for (i = 0; i < dn1->comp_num; i++) {
 823                 newdn->components[i] = ldb_dn_copy_component(newdn->components,
 824                                                            &(dn1->components[i]));
 825         }
 826
 827         return newdn;
 828
 829 failed:
 830         talloc_free(newdn);
 831         return NULL;
 832 }
 833
 834 struct ldb_dn *ldb_dn_string_compose(void *mem_ctx, const struct ldb_dn *base, const char *child_fmt, ...)
 835 {
 836         struct ldb_dn *dn;
 837         char *child_str;
 838         va_list ap;
 839
 840         if (child_fmt == NULL) return NULL;
 841
 842         va_start(ap, child_fmt);
 843         child_str = talloc_vasprintf(mem_ctx, child_fmt, ap);
 844         va_end(ap);
 845
 846         if (child_str == NULL) return NULL;
 847
 848         dn = ldb_dn_compose(mem_ctx, ldb_dn_explode(mem_ctx, child_str), base);
 849
 850         talloc_free(child_str);
 851
 852         return dn;
 853 }
 854
 855 struct ldb_dn_component *ldb_dn_get_rdn(void *mem_ctx, const struct ldb_dn *dn)
 856 {
 857         struct ldb_dn_component *rdn;
 858
 859         if (dn == NULL) return NULL;
 860
 861         if (dn->comp_num < 1) {
 862                 return NULL;
 863         }
 864
 865         rdn = talloc(mem_ctx, struct ldb_dn_component);
 866         if (rdn == NULL) return NULL;
 867
 868         *rdn = ldb_dn_copy_component(mem_ctx, &dn->components[0]);
 869         if (rdn->name == NULL) {
 870                 talloc_free(rdn);
 871                 return NULL;
 872         }
 873
 874         return rdn;
 875 }
 876
 877 /* Create a 'canonical name' string from a DN:
 878
 879    ie dc=samba,dc=org -> samba.org/
 880       uid=administrator,ou=users,dc=samba,dc=org = samba.org/users/administrator
 881
 882    There are two formats, the EX format has the last / replaced with a newline (\n).
 883
 884 */
 885 static char *ldb_dn_canonical(void *mem_ctx, const struct ldb_dn *dn, int ex_format) {
 886         int i;
 887         char *cracked = NULL;
 888
 889         /* Walk backwards down the DN, grabbing 'dc' components at first */
 890         for (i = dn->comp_num - 1 ; i >= 0; i--) {
 891                 if (ldb_attr_cmp(dn->components[i].name, "dc") != 0) {
 892                         break;
 893                 }
 894                 if (cracked) {
 895                         cracked = talloc_asprintf(mem_ctx, "%s.%s",
 896                                                   ldb_dn_escape_value(mem_ctx, dn->components[i].value),
 897                                                   cracked);
 898                 } else {
 899                         cracked = ldb_dn_escape_value(mem_ctx, dn->components[i].value);
 900                 }
 901                 if (!cracked) {
 902                         return NULL;
 903                 }
 904         }
 905
 906         /* Only domain components?  Finish here */
 907         if (i < 0) {
 908                 if (ex_format) {
 909                         cracked = talloc_asprintf(mem_ctx, "%s\n", cracked);
 910                 } else {
 911                         cracked = talloc_asprintf(mem_ctx, "%s/", cracked);
 912                 }
 913                 return cracked;
 914         }
 915
 916         /* Now walk backwards appending remaining components */
 917         for (; i > 0; i--) {
 918                 cracked = talloc_asprintf(mem_ctx, "%s/%s", cracked,
 919                                           ldb_dn_escape_value(mem_ctx, dn->components[i].value));
 920                 if (!cracked) {
 921                         return NULL;
 922                 }
 923         }
 924
 925         /* Last one, possibly a newline for the 'ex' format */
 926         if (ex_format) {
 927                 cracked = talloc_asprintf(mem_ctx, "%s\n%s", cracked,
 928                                           ldb_dn_escape_value(mem_ctx, dn->components[i].value));
 929         } else {
 930                 cracked = talloc_asprintf(mem_ctx, "%s/%s", cracked,
 931                                           ldb_dn_escape_value(mem_ctx, dn->components[i].value));
 932         }
 933         return cracked;
 934 }
 935
 936 /* Wrapper functions for the above, for the two different string formats */
 937 char *ldb_dn_canonical_string(void *mem_ctx, const struct ldb_dn *dn) {
 938         return ldb_dn_canonical(mem_ctx, dn, 0);
 939
 940 }
 941
 942 char *ldb_dn_canonical_ex_string(void *mem_ctx, const struct ldb_dn *dn) {
 943         return ldb_dn_canonical(mem_ctx, dn, 1);
 944 }