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   1 /* $OpenLDAP$ */
   2 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
   3  *
   4  * Copyright 2000-2004 The OpenLDAP Foundation.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted only as authorized by the OpenLDAP
   9  * Public License.
  10  *
  11  * A copy of this license is available in the file LICENSE in the
  12  * top-level directory of the distribution or, alternatively, at
  13  * <http://www.OpenLDAP.org/license.html>.
  14  */
  15 /* ACKNOWLEDGEMENT:
  16  * This work was initially developed by Pierangelo Masarati for
  17  * inclusion in OpenLDAP Software.
  18  */
  19
  20 #include <portable.h>
  21
  22 #include "rewrite-int.h"
  23
  24 /*
  25  * Appends a rule to the double linked list of rules
  26  * Helper for rewrite_rule_compile
  27  */
  28 static int
  29 append_rule(
  30                 struct rewrite_context *context,
  31                 struct rewrite_rule *rule
  32 )
  33 {
  34         struct rewrite_rule *r;
  35
  36         assert( context != NULL );
  37         assert( context->lc_rule != NULL );
  38         assert( rule != NULL );
  39
  40         for ( r = context->lc_rule; r->lr_next != NULL; r = r->lr_next );
  41         r->lr_next = rule;
  42         rule->lr_prev = r;
  43
  44         return REWRITE_SUCCESS;
  45 }
  46
  47 /*
  48  * Appends an action to the linked list of actions
  49  * Helper for rewrite_rule_compile
  50  */
  51 static int
  52 append_action(
  53                 struct rewrite_action **pbase,
  54                 struct rewrite_action *action
  55 )
  56 {
  57         struct rewrite_action **pa;
  58
  59         assert( pbase != NULL );
  60         assert( action != NULL );
  61
  62         for ( pa = pbase; *pa != NULL; pa = &(*pa)->la_next );
  63         *pa = action;
  64
  65         return REWRITE_SUCCESS;
  66 }
  67
  68 static int
  69 destroy_action(
  70                 struct rewrite_action **paction
  71 )
  72 {
  73         struct rewrite_action   *action;
  74
  75         assert( paction );
  76         assert( *paction );
  77
  78         action = *paction;
  79
  80         /* do something */
  81         switch ( action->la_type ) {
  82         case REWRITE_FLAG_GOTO:
  83         case REWRITE_FLAG_USER: {
  84                 int *pi = (int *)action->la_args;
  85
  86                 if ( pi ) {
  87                         free( pi );
  88                 }
  89                 break;
  90         }
  91
  92         default:
  93                 break;
  94         }
  95
  96         free( action );
  97         *paction = NULL;
  98
  99         return 0;
 100 }
 101
 102 /*
 103  * In case of error it returns NULL and does not free all the memory
 104  * it allocated; as this is a once only phase, and an error at this stage
 105  * would require the server to stop, there is no need to be paranoid
 106  * about memory allocation
 107  */
 108 int
 109 rewrite_rule_compile(
 110                 struct rewrite_info *info,
 111                 struct rewrite_context *context,
 112                 const char *pattern,
 113                 const char *result,
 114                 const char *flagstring
 115 )
 116 {
 117         int flags = REWRITE_REGEX_EXTENDED | REWRITE_REGEX_ICASE;
 118         int mode = REWRITE_RECURSE;
 119         int max_passes = info->li_max_passes_per_rule;
 120
 121         struct rewrite_rule *rule = NULL;
 122         struct rewrite_subst *subst = NULL;
 123         struct rewrite_action *action = NULL, *first_action = NULL;
 124
 125         const char *p;
 126
 127         assert( info != NULL );
 128         assert( context != NULL );
 129         assert( pattern != NULL );
 130         assert( result != NULL );
 131
 132         /*
 133          * A null flagstring should be allowed
 134          */
 135
 136         /*
 137          * Take care of substitution string
 138          */
 139         subst = rewrite_subst_compile( info, result );
 140         if ( subst == NULL ) {
 141                 return REWRITE_ERR;
 142         }
 143
 144         /*
 145          * Take care of flags
 146          */
 147         for ( p = flagstring; p[ 0 ] != '\0'; p++ ) {
 148                 switch( p[ 0 ] ) {
 149
 150                 /*
 151                  * REGEX flags
 152                  */
 153                 case REWRITE_FLAG_HONORCASE:            /* 'C' */
 154                         /*
 155                          * Honor case (default is case insensitive)
 156                          */
 157                         flags &= ~REWRITE_REGEX_ICASE;
 158                         break;
 159
 160                 case REWRITE_FLAG_BASICREGEX:           /* 'R' */
 161                         /*
 162                          * Use POSIX Basic Regular Expression syntax
 163                          * instead of POSIX Extended Regular Expression
 164                          * syntax (default)
 165                          */
 166                         flags &= ~REWRITE_REGEX_EXTENDED;
 167                         break;
 168
 169                 /*
 170                  * Execution mode flags
 171                  */
 172                 case REWRITE_FLAG_EXECONCE:             /* ':' */
 173                         /*
 174                          * Apply rule once only
 175                          */
 176                         mode &= ~REWRITE_RECURSE;
 177                         mode |= REWRITE_EXEC_ONCE;
 178                         break;
 179
 180                 /*
 181                  * Special action flags
 182                  */
 183                 case REWRITE_FLAG_STOP:                 /* '@' */
 184                         /*
 185                          * Bail out after applying rule
 186                          */
 187                         action = calloc( sizeof( struct rewrite_action ), 1 );
 188                         if ( action == NULL ) {
 189                                 /* cleanup ... */
 190                                 return REWRITE_ERR;
 191                         }
 192
 193                         action->la_type = REWRITE_ACTION_STOP;
 194                         break;
 195
 196                 case REWRITE_FLAG_UNWILLING:            /* '#' */
 197                         /*
 198                          * Matching objs will be marked as gone!
 199                          */
 200                         action = calloc( sizeof( struct rewrite_action ), 1 );
 201                         if ( action == NULL ) {
 202                                 /* cleanup ... */
 203                                 return REWRITE_ERR;
 204                         }
 205
 206                         mode &= ~REWRITE_RECURSE;
 207                         mode |= REWRITE_EXEC_ONCE;
 208                         action->la_type = REWRITE_ACTION_UNWILLING;
 209                         break;
 210
 211                 case REWRITE_FLAG_GOTO:                         /* 'G' */
 212                         /*
 213                          * After applying rule, jump N rules
 214                          */
 215
 216                 case REWRITE_FLAG_USER: {                       /* 'U' */
 217                         /*
 218                          * After applying rule, return user-defined
 219                          * error code
 220                          */
 221                         char *next = NULL;
 222                         int *d;
 223
 224                         if ( p[ 1 ] != '{' ) {
 225                                 /* XXX Need to free stuff */
 226                                 return REWRITE_ERR;
 227                         }
 228
 229                         d = malloc( sizeof( int ) );
 230                         if ( d == NULL ) {
 231                                 /* XXX Need to free stuff */
 232                                 return REWRITE_ERR;
 233                         }
 234
 235                         d[ 0 ] = strtol( &p[ 2 ], &next, 0 );
 236                         if ( next == NULL || next == &p[ 2 ] || next[0] != '}' ) {
 237                                 /* XXX Need to free stuff */
 238                                 return REWRITE_ERR;
 239                         }
 240
 241                         action = calloc( sizeof( struct rewrite_action ), 1 );
 242                         if ( action == NULL ) {
 243                                 /* cleanup ... */
 244                                 return REWRITE_ERR;
 245                         }
 246                         switch ( p[ 0 ] ) {
 247                         case REWRITE_FLAG_GOTO:
 248                                 action->la_type = REWRITE_ACTION_GOTO;
 249                                 break;
 250
 251                         case REWRITE_FLAG_USER:
 252                                 action->la_type = REWRITE_ACTION_USER;
 253                                 break;
 254
 255                         default:
 256                                 assert(0);
 257                         }
 258
 259                         action->la_args = (void *)d;
 260
 261                         p = next;       /* p is incremented by the for ... */
 262
 263                         break;
 264                 }
 265
 266                 case REWRITE_FLAG_MAX_PASSES: {                 /* 'U' */
 267                         /*
 268                          * Set the number of max passes per rule
 269                          */
 270                         char *next = NULL;
 271
 272                         if ( p[ 1 ] != '{' ) {
 273                                 /* XXX Need to free stuff */
 274                                 return REWRITE_ERR;
 275                         }
 276
 277                         max_passes = strtol( &p[ 2 ], &next, 0 );
 278                         if ( next == NULL || next == &p[ 2 ] || next[0] != '}' ) {
 279                                 /* XXX Need to free stuff */
 280                                 return REWRITE_ERR;
 281                         }
 282
 283                         if ( max_passes < 1 ) {
 284                                 /* FIXME: nonsense ... */
 285                                 max_passes = 1;
 286                         }
 287
 288                         p = next;       /* p is incremented by the for ... */
 289
 290                         break;
 291                 }
 292
 293                 case REWRITE_FLAG_IGNORE_ERR:               /* 'I' */
 294                         /*
 295                          * Ignore errors!
 296                          */
 297                         action = calloc( sizeof( struct rewrite_action ), 1 );
 298                         if ( action == NULL ) {
 299                                 /* cleanup ... */
 300                                 return REWRITE_ERR;
 301                         }
 302
 303                         action->la_type = REWRITE_ACTION_IGNORE_ERR;
 304                         break;
 305
 306                 /*
 307                  * Other flags ...
 308                  */
 309                 default:
 310                         /*
 311                          * Unimplemented feature (complain only)
 312                          */
 313                         break;
 314                 }
 315
 316                 /*
 317                  * Stupid way to append to a list ...
 318                  */
 319                 if ( action != NULL ) {
 320                         append_action( &first_action, action );
 321                         action = NULL;
 322                 }
 323         }
 324
 325         /*
 326          * Finally, rule allocation
 327          */
 328         rule = calloc( sizeof( struct rewrite_rule ), 1 );
 329         if ( rule == NULL ) {
 330                 /* charray_free( res ); */
 331                 /*
 332                  * XXX need to free the value subst stuff!
 333                  */
 334                 return REWRITE_ERR;
 335         }
 336
 337         /*
 338          * REGEX compilation (luckily I don't need to take care of this ...)
 339          */
 340         if ( regcomp( &rule->lr_regex, ( char * )pattern, flags ) != 0 ) {
 341                 /* charray_free( res ); */
 342                 /*
 343                  *XXX need to free the value subst stuff!
 344                  */
 345                 free( rule );
 346                 return REWRITE_ERR;
 347         }
 348
 349         /*
 350          * Just to remember them ...
 351          */
 352         rule->lr_pattern = strdup( pattern );
 353         rule->lr_subststring = strdup( result );
 354         rule->lr_flagstring = strdup( flagstring );
 355
 356         /*
 357          * Load compiled data into rule
 358          */
 359         rule->lr_subst = subst;
 360
 361         /*
 362          * Set various parameters
 363          */
 364         rule->lr_flags = flags;         /* don't really need any longer ... */
 365         rule->lr_mode = mode;
 366         rule->lr_max_passes = max_passes;
 367         rule->lr_action = first_action;
 368
 369         /*
 370          * Append rule at the end of the rewrite context
 371          */
 372         append_rule( context, rule );
 373
 374         return REWRITE_SUCCESS;
 375 }
 376
 377 /*
 378  * Rewrites string according to rule; may return:
 379  *      OK:     fine; if *result != NULL rule matched and rewrite succeeded.
 380  *      STOP:   fine, rule matched; stop processing following rules
 381  *      UNWILL: rule matched; force 'unwilling to perform'
 382  */
 383 int
 384 rewrite_rule_apply(
 385                 struct rewrite_info *info,
 386                 struct rewrite_op *op,
 387                 struct rewrite_rule *rule,
 388                 const char *arg,
 389                 char **result
 390                 )
 391 {
 392         size_t nmatch = REWRITE_MAX_MATCH;
 393         regmatch_t match[ REWRITE_MAX_MATCH ];
 394
 395         int rc = REWRITE_SUCCESS;
 396
 397         char *string;
 398         int strcnt = 0;
 399         struct berval val = { 0, NULL };
 400
 401         assert( info != NULL );
 402         assert( op != NULL );
 403         assert( rule != NULL );
 404         assert( arg != NULL );
 405         assert( result != NULL );
 406
 407         *result = NULL;
 408
 409         string = (char *)arg;
 410
 411         /*
 412          * In case recursive match is required (default)
 413          */
 414 recurse:;
 415
 416         Debug( LDAP_DEBUG_TRACE, "==> rewrite_rule_apply"
 417                         " rule='%s' string='%s' [%d pass(es)]\n",
 418                         rule->lr_pattern, string, strcnt + 1 );
 419
 420         op->lo_num_passes++;
 421         if ( regexec( &rule->lr_regex, string, nmatch, match, 0 ) != 0 ) {
 422                 if ( *result == NULL && strcnt > 0 ) {
 423                         free( string );
 424                         string = NULL;
 425                 }
 426
 427                 /*
 428                  * No match is OK; *result = NULL means no match
 429                  */
 430                 return REWRITE_REGEXEC_OK;
 431         }
 432
 433         rc = rewrite_subst_apply( info, op, rule->lr_subst, string,
 434                         match, &val );
 435
 436         *result = val.bv_val;
 437         val.bv_val = NULL;
 438         if ( strcnt > 0 ) {
 439                 free( string );
 440                 string = NULL;
 441         }
 442
 443         if ( rc != REWRITE_REGEXEC_OK ) {
 444                 return rc;
 445         }
 446
 447         if ( ( rule->lr_mode & REWRITE_RECURSE ) == REWRITE_RECURSE
 448                         && op->lo_num_passes < info->li_max_passes
 449                         && ++strcnt < rule->lr_max_passes ) {
 450                 string = *result;
 451
 452                 goto recurse;
 453         }
 454
 455         return REWRITE_REGEXEC_OK;
 456 }
 457
 458 int
 459 rewrite_rule_destroy(
 460                 struct rewrite_rule **prule
 461                 )
 462 {
 463         struct rewrite_rule *rule;
 464         struct rewrite_action *action;
 465
 466         assert( prule );
 467         assert( *prule );
 468
 469         rule = *prule;
 470
 471         if ( rule->lr_pattern ) {
 472                 free( rule->lr_pattern );
 473                 rule->lr_pattern = NULL;
 474         }
 475
 476         if ( rule->lr_subststring ) {
 477                 free( rule->lr_subststring );
 478                 rule->lr_subststring = NULL;
 479         }
 480
 481         if ( rule->lr_flagstring ) {
 482                 free( rule->lr_flagstring );
 483                 rule->lr_flagstring = NULL;
 484         }
 485
 486         if ( rule->lr_subst ) {
 487                 rewrite_subst_destroy( &rule->lr_subst );
 488         }
 489
 490         regfree( &rule->lr_regex );
 491
 492         for ( action = rule->lr_action; action; ) {
 493                 struct rewrite_action *curraction = action;
 494
 495                 action = action->la_next;
 496                 destroy_action( &curraction );
 497         }
 498
 499         free( rule );
 500         *prule = NULL;
 501
 502         return 0;
 503 }
 504