git.sur5r.net Git - openldap/blob - libraries/librewrite/rule.c

   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                         //mode &= ~REWRITE_RECURSE;
 194                         //mode |= REWRITE_EXEC_ONCE;
 195                         action->la_type = REWRITE_ACTION_STOP;
 196                         break;
 197
 198                 case REWRITE_FLAG_UNWILLING:            /* '#' */
 199                         /*
 200                          * Matching objs will be marked as gone!
 201                          */
 202                         action = calloc( sizeof( struct rewrite_action ), 1 );
 203                         if ( action == NULL ) {
 204                                 /* cleanup ... */
 205                                 return REWRITE_ERR;
 206                         }
 207
 208                         mode &= ~REWRITE_RECURSE;
 209                         mode |= REWRITE_EXEC_ONCE;
 210                         action->la_type = REWRITE_ACTION_UNWILLING;
 211                         break;
 212
 213                 case REWRITE_FLAG_GOTO:                         /* 'G' */
 214                         /*
 215                          * After applying rule, jump N rules
 216                          */
 217
 218                 case REWRITE_FLAG_USER: {                       /* 'U' */
 219                         /*
 220                          * After applying rule, return user-defined
 221                          * error code
 222                          */
 223                         char *next = NULL;
 224                         int *d;
 225
 226                         if ( p[ 1 ] != '{' ) {
 227                                 /* XXX Need to free stuff */
 228                                 return REWRITE_ERR;
 229                         }
 230
 231                         d = malloc( sizeof( int ) );
 232                         if ( d == NULL ) {
 233                                 /* XXX Need to free stuff */
 234                                 return REWRITE_ERR;
 235                         }
 236
 237                         d[ 0 ] = strtol( &p[ 2 ], &next, 0 );
 238                         if ( next == NULL || next == &p[ 2 ] || next[0] != '}' ) {
 239                                 /* XXX Need to free stuff */
 240                                 return REWRITE_ERR;
 241                         }
 242
 243                         action = calloc( sizeof( struct rewrite_action ), 1 );
 244                         if ( action == NULL ) {
 245                                 /* cleanup ... */
 246                                 return REWRITE_ERR;
 247                         }
 248                         switch ( p[ 0 ] ) {
 249                         case REWRITE_FLAG_GOTO:
 250                                 action->la_type = REWRITE_ACTION_GOTO;
 251                                 break;
 252
 253                         case REWRITE_FLAG_USER:
 254                                 action->la_type = REWRITE_ACTION_USER;
 255                                 break;
 256
 257                         default:
 258                                 assert(0);
 259                         }
 260
 261                         action->la_args = (void *)d;
 262
 263                         p = next;       /* p is incremented by the for ... */
 264
 265                         break;
 266                 }
 267
 268                 case REWRITE_FLAG_MAX_PASSES: {                 /* 'U' */
 269                         /*
 270                          * Set the number of max passes per rule
 271                          */
 272                         char *next = NULL;
 273
 274                         if ( p[ 1 ] != '{' ) {
 275                                 /* XXX Need to free stuff */
 276                                 return REWRITE_ERR;
 277                         }
 278
 279                         max_passes = strtol( &p[ 2 ], &next, 0 );
 280                         if ( next == NULL || next == &p[ 2 ] || next[0] != '}' ) {
 281                                 /* XXX Need to free stuff */
 282                                 return REWRITE_ERR;
 283                         }
 284
 285                         if ( max_passes < 1 ) {
 286                                 /* FIXME: nonsense ... */
 287                                 max_passes = 1;
 288                         }
 289
 290                         p = next;       /* p is incremented by the for ... */
 291
 292                         break;
 293                 }
 294
 295                 case REWRITE_FLAG_IGNORE_ERR:               /* 'I' */
 296                         /*
 297                          * Ignore errors!
 298                          */
 299                         action = calloc( sizeof( struct rewrite_action ), 1 );
 300                         if ( action == NULL ) {
 301                                 /* cleanup ... */
 302                                 return REWRITE_ERR;
 303                         }
 304
 305                         action->la_type = REWRITE_ACTION_IGNORE_ERR;
 306                         break;
 307
 308                 /*
 309                  * Other flags ...
 310                  */
 311                 default:
 312                         /*
 313                          * Unimplemented feature (complain only)
 314                          */
 315                         break;
 316                 }
 317
 318                 /*
 319                  * Stupid way to append to a list ...
 320                  */
 321                 if ( action != NULL ) {
 322                         append_action( &first_action, action );
 323                         action = NULL;
 324                 }
 325         }
 326
 327         /*
 328          * Finally, rule allocation
 329          */
 330         rule = calloc( sizeof( struct rewrite_rule ), 1 );
 331         if ( rule == NULL ) {
 332                 /* charray_free( res ); */
 333                 /*
 334                  * XXX need to free the value subst stuff!
 335                  */
 336                 return REWRITE_ERR;
 337         }
 338
 339         /*
 340          * REGEX compilation (luckily I don't need to take care of this ...)
 341          */
 342         if ( regcomp( &rule->lr_regex, ( char * )pattern, flags ) != 0 ) {
 343                 /* charray_free( res ); */
 344                 /*
 345                  *XXX need to free the value subst stuff!
 346                  */
 347                 free( rule );
 348                 return REWRITE_ERR;
 349         }
 350
 351         /*
 352          * Just to remember them ...
 353          */
 354         rule->lr_pattern = strdup( pattern );
 355         rule->lr_subststring = strdup( result );
 356         rule->lr_flagstring = strdup( flagstring );
 357
 358         /*
 359          * Load compiled data into rule
 360          */
 361         rule->lr_subst = subst;
 362
 363         /*
 364          * Set various parameters
 365          */
 366         rule->lr_flags = flags;         /* don't really need any longer ... */
 367         rule->lr_mode = mode;
 368         rule->lr_max_passes = max_passes;
 369         rule->lr_action = first_action;
 370
 371         /*
 372          * Append rule at the end of the rewrite context
 373          */
 374         append_rule( context, rule );
 375
 376         return REWRITE_SUCCESS;
 377 }
 378
 379 /*
 380  * Rewrites string according to rule; may return:
 381  *      OK:     fine; if *result != NULL rule matched and rewrite succeeded.
 382  *      STOP:   fine, rule matched; stop processing following rules
 383  *      UNWILL: rule matched; force 'unwilling to perform'
 384  */
 385 int
 386 rewrite_rule_apply(
 387                 struct rewrite_info *info,
 388                 struct rewrite_op *op,
 389                 struct rewrite_rule *rule,
 390                 const char *arg,
 391                 char **result
 392                 )
 393 {
 394         size_t nmatch = REWRITE_MAX_MATCH;
 395         regmatch_t match[ REWRITE_MAX_MATCH ];
 396
 397         int rc = REWRITE_SUCCESS;
 398
 399         char *string;
 400         int strcnt = 0;
 401         struct berval val = { 0, NULL };
 402
 403         assert( info != NULL );
 404         assert( op != NULL );
 405         assert( rule != NULL );
 406         assert( arg != NULL );
 407         assert( result != NULL );
 408
 409         *result = NULL;
 410
 411         string = (char *)arg;
 412
 413         /*
 414          * In case recursive match is required (default)
 415          */
 416 recurse:;
 417
 418         Debug( LDAP_DEBUG_TRACE, "==> rewrite_rule_apply"
 419                         " rule='%s' string='%s' [%s pass(es)]\n",
 420                         rule->lr_pattern, string, strcnt + 1 );
 421
 422         op->lo_num_passes++;
 423         if ( regexec( &rule->lr_regex, string, nmatch, match, 0 ) != 0 ) {
 424                 if ( *result == NULL && strcnt > 0 ) {
 425                         free( string );
 426                         string = NULL;
 427                 }
 428
 429                 /*
 430                  * No match is OK; *result = NULL means no match
 431                  */
 432                 return REWRITE_REGEXEC_OK;
 433         }
 434
 435         rc = rewrite_subst_apply( info, op, rule->lr_subst, string,
 436                         match, &val );
 437
 438         *result = val.bv_val;
 439         val.bv_val = NULL;
 440         if ( strcnt > 0 ) {
 441                 free( string );
 442                 string = NULL;
 443         }
 444
 445         if ( rc != REWRITE_REGEXEC_OK ) {
 446                 return rc;
 447         }
 448
 449         if ( ( rule->lr_mode & REWRITE_RECURSE ) == REWRITE_RECURSE
 450                         && op->lo_num_passes < info->li_max_passes
 451                         && ++strcnt < rule->lr_max_passes ) {
 452                 string = *result;
 453
 454                 goto recurse;
 455         }
 456
 457         return REWRITE_REGEXEC_OK;
 458 }
 459
 460 int
 461 rewrite_rule_destroy(
 462                 struct rewrite_rule **prule
 463                 )
 464 {
 465         struct rewrite_rule *rule;
 466         struct rewrite_action *action;
 467
 468         assert( prule );
 469         assert( *prule );
 470
 471         rule = *prule;
 472
 473         if ( rule->lr_pattern ) {
 474                 free( rule->lr_pattern );
 475                 rule->lr_pattern = NULL;
 476         }
 477
 478         if ( rule->lr_subststring ) {
 479                 free( rule->lr_subststring );
 480                 rule->lr_subststring = NULL;
 481         }
 482
 483         if ( rule->lr_flagstring ) {
 484                 free( rule->lr_flagstring );
 485                 rule->lr_flagstring = NULL;
 486         }
 487
 488         if ( rule->lr_subst ) {
 489                 rewrite_subst_destroy( &rule->lr_subst );
 490         }
 491
 492         regfree( &rule->lr_regex );
 493
 494         for ( action = rule->lr_action; action; ) {
 495                 struct rewrite_action *curraction = action;
 496
 497                 action = action->la_next;
 498                 destroy_action( &curraction );
 499         }
 500
 501         free( rule );
 502         *prule = NULL;
 503
 504         return 0;
 505 }
 506