diff options
Diffstat (limited to 'libraries/librewrite/context.c')
| -rw-r--r-- | libraries/librewrite/context.c | 474 |
1 files changed, 474 insertions, 0 deletions
diff --git a/libraries/librewrite/context.c b/libraries/librewrite/context.c new file mode 100644 index 0000000..cc7854c --- /dev/null +++ b/libraries/librewrite/context.c @@ -0,0 +1,474 @@ +/* $OpenLDAP$ */ +/* This work is part of OpenLDAP Software <http://www.openldap.org/>. + * + * Copyright 2000-2021 The OpenLDAP Foundation. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted only as authorized by the OpenLDAP + * Public License. + * + * A copy of this license is available in the file LICENSE in the + * top-level directory of the distribution or, alternatively, at + * <http://www.OpenLDAP.org/license.html>. + */ +/* ACKNOWLEDGEMENT: + * This work was initially developed by Pierangelo Masarati for + * inclusion in OpenLDAP Software. + */ + +#include <portable.h> + +#include "rewrite-int.h" + +/* + * Compares two struct rewrite_context based on the name; + * used by avl stuff + */ +static int +rewrite_context_cmp( + const void *c1, + const void *c2 +) +{ + const struct rewrite_context *lc1, *lc2; + + lc1 = (const struct rewrite_context *)c1; + lc2 = (const struct rewrite_context *)c2; + + assert( c1 != NULL ); + assert( c2 != NULL ); + assert( lc1->lc_name != NULL ); + assert( lc2->lc_name != NULL ); + + return strcasecmp( lc1->lc_name, lc2->lc_name ); +} + +/* + * Returns -1 in case a duplicate struct rewrite_context + * has been inserted; used by avl stuff + */ +static int +rewrite_context_dup( + void *c1, + void *c2 + ) +{ + struct rewrite_context *lc1, *lc2; + + lc1 = (struct rewrite_context *)c1; + lc2 = (struct rewrite_context *)c2; + + assert( c1 != NULL ); + assert( c2 != NULL ); + assert( lc1->lc_name != NULL ); + assert( lc2->lc_name != NULL ); + + return( strcasecmp( lc1->lc_name, lc2->lc_name) == 0 ? -1 : 0 ); +} + +/* + * Finds the context named rewriteContext in the context tree + */ +struct rewrite_context * +rewrite_context_find( + struct rewrite_info *info, + const char *rewriteContext +) +{ + struct rewrite_context *context, c; + + assert( info != NULL ); + assert( rewriteContext != NULL ); + + /* + * Fetches the required rewrite context + */ + c.lc_name = (char *)rewriteContext; + context = (struct rewrite_context *)avl_find( info->li_context, + (caddr_t)&c, rewrite_context_cmp ); + if ( context == NULL ) { + return NULL; + } + + /* + * De-aliases the context if required + */ + if ( context->lc_alias ) { + return context->lc_alias; + } + + return context; +} + +/* + * Creates a new context called rewriteContext and stores in into the tree + */ +struct rewrite_context * +rewrite_context_create( + struct rewrite_info *info, + const char *rewriteContext +) +{ + struct rewrite_context *context; + int rc; + + assert( info != NULL ); + assert( rewriteContext != NULL ); + + context = calloc( sizeof( struct rewrite_context ), 1 ); + if ( context == NULL ) { + return NULL; + } + + /* + * Context name + */ + context->lc_name = strdup( rewriteContext ); + if ( context->lc_name == NULL ) { + free( context ); + return NULL; + } + + /* + * The first, empty rule + */ + context->lc_rule = calloc( sizeof( struct rewrite_rule ), 1 ); + if ( context->lc_rule == NULL ) { + free( context->lc_name ); + free( context ); + return NULL; + } + memset( context->lc_rule, 0, sizeof( struct rewrite_rule ) ); + + /* + * Add context to tree + */ + rc = avl_insert( &info->li_context, (caddr_t)context, + rewrite_context_cmp, rewrite_context_dup ); + if ( rc == -1 ) { + free( context->lc_rule ); + free( context->lc_name ); + free( context ); + return NULL; + } + + return context; +} + +/* + * Finds the next rule according to a goto action statement, + * or null in case of error. + * Helper for rewrite_context_apply. + */ +static struct rewrite_rule * +rewrite_action_goto( + struct rewrite_action *action, + struct rewrite_rule *rule +) +{ + int n; + + assert( action != NULL ); + assert( action->la_args != NULL ); + assert( rule != NULL ); + + n = ((int *)action->la_args)[ 0 ]; + + if ( n > 0 ) { + for ( ; n > 1 && rule != NULL ; n-- ) { + rule = rule->lr_next; + } + } else if ( n <= 0 ) { + for ( ; n < 1 && rule != NULL ; n++ ) { + rule = rule->lr_prev; + } + } + + return rule; +} + +/* + * Rewrites string according to context; may return: + * OK: fine; if *result != NULL rule matched and rewrite succeeded. + * STOP: fine, rule matched; stop processing following rules + * UNWILL: rule matched; force 'unwilling to perform' + */ +int +rewrite_context_apply( + struct rewrite_info *info, + struct rewrite_op *op, + struct rewrite_context *context, + const char *string, + char **result +) +{ + struct rewrite_rule *rule; + char *s, *res = NULL; + int return_code = REWRITE_REGEXEC_OK; + + assert( info != NULL ); + assert( op != NULL ); + assert( context != NULL ); + assert( context->lc_rule != NULL ); + assert( string != NULL ); + assert( result != NULL ); + + op->lo_depth++; + + Debug( LDAP_DEBUG_TRACE, "==> rewrite_context_apply" + " [depth=%d] string='%s'\n", + op->lo_depth, string, 0 ); + assert( op->lo_depth > 0 ); + + s = (char *)string; + + for ( rule = context->lc_rule->lr_next; + rule != NULL && op->lo_num_passes < info->li_max_passes; + rule = rule->lr_next, op->lo_num_passes++ ) { + int rc; + + /* + * Apply a single rule + */ + rc = rewrite_rule_apply( info, op, rule, s, &res ); + + /* + * A rule may return: + * OK with result != NULL if matched + * ERR if anything was wrong + * UNWILLING if the server should drop the request + * the latter case in honored immediately; + * the other two may require some special actions to take + * place. + */ + switch ( rc ) { + + case REWRITE_REGEXEC_ERR: + Debug( LDAP_DEBUG_ANY, "==> rewrite_context_apply" + " error ...\n", 0, 0, 0); + + /* + * Checks for special actions to be taken + * in case of error ... + */ + if ( rule->lr_action != NULL ) { + struct rewrite_action *action; + int do_continue = 0; + + for ( action = rule->lr_action; + action != NULL; + action = action->la_next ) { + switch ( action->la_type ) { + + /* + * This action takes precedence + * over the others in case of failure + */ + case REWRITE_ACTION_IGNORE_ERR: + Debug( LDAP_DEBUG_ANY, + "==> rewrite_context_apply" + " ignoring error ...\n", 0, 0, 0 ); + do_continue = 1; + break; + + /* + * Goto is honored only if it comes + * after ignore error + */ + case REWRITE_ACTION_GOTO: + if ( do_continue ) { + rule = rewrite_action_goto( action, rule ); + if ( rule == NULL ) { + return_code = REWRITE_REGEXEC_ERR; + goto rc_end_of_context; + } + } + break; + + /* + * Other actions are ignored + */ + default: + break; + } + } + + if ( do_continue ) { + if ( rule->lr_next == NULL ) { + res = s; + } + goto rc_continue; + } + } + + /* + * Default behavior is to bail out ... + */ + return_code = REWRITE_REGEXEC_ERR; + goto rc_end_of_context; + + /* + * OK means there were no errors or special return codes; + * if res is defined, it means the rule matched and we + * got a sucessful rewriting + */ + case REWRITE_REGEXEC_OK: + + /* + * It matched! Check for actions ... + */ + if ( res != NULL ) { + struct rewrite_action *action; + + if ( s != string && s != res ) { + free( s ); + } + s = res; + + for ( action = rule->lr_action; + action != NULL; + action = action->la_next ) { + + switch ( action->la_type ) { + + /* + * This ends the rewrite context + * successfully + */ + case REWRITE_ACTION_STOP: + goto rc_end_of_context; + + /* + * This instructs the server to return + * an `unwilling to perform' error + * message + */ + case REWRITE_ACTION_UNWILLING: + return_code = REWRITE_REGEXEC_UNWILLING; + goto rc_end_of_context; + + /* + * This causes the processing to + * jump n rules back and forth + */ + case REWRITE_ACTION_GOTO: + rule = rewrite_action_goto( action, rule ); + if ( rule == NULL ) { + return_code = REWRITE_REGEXEC_ERR; + goto rc_end_of_context; + } + break; + + /* + * This ends the rewrite context + * and returns a user-defined + * error code + */ + case REWRITE_ACTION_USER: + return_code = ((int *)action->la_args)[ 0 ]; + goto rc_end_of_context; + + default: + /* ... */ + break; + } + } + + /* + * If result was OK and string didn't match, + * in case of last rule we need to set the + * result back to the string + */ + } else if ( rule->lr_next == NULL ) { + res = s; + } + + break; + + /* + * A STOP has propagated ... + */ + case REWRITE_REGEXEC_STOP: + goto rc_end_of_context; + + /* + * This will instruct the server to return + * an `unwilling to perform' error message + */ + case REWRITE_REGEXEC_UNWILLING: + return_code = REWRITE_REGEXEC_UNWILLING; + goto rc_end_of_context; + + /* + * A user-defined error code has propagated ... + */ + default: + assert( rc >= REWRITE_REGEXEC_USER ); + goto rc_end_of_context; + + } + +rc_continue:; /* sent here by actions that require to continue */ + + } + +rc_end_of_context:; + *result = res; + + Debug( LDAP_DEBUG_TRACE, "==> rewrite_context_apply" + " [depth=%d] res={%d,'%s'}\n", + op->lo_depth, return_code, ( res ? res : "NULL" ) ); + + assert( op->lo_depth > 0 ); + op->lo_depth--; + + return return_code; +} + +void +rewrite_context_free( + void *tmp +) +{ + struct rewrite_context *context = (struct rewrite_context *)tmp; + + assert( tmp != NULL ); + + rewrite_context_destroy( &context ); +} + +int +rewrite_context_destroy( + struct rewrite_context **pcontext +) +{ + struct rewrite_context *context; + struct rewrite_rule *r; + + assert( pcontext != NULL ); + assert( *pcontext != NULL ); + + context = *pcontext; + + assert( context->lc_rule != NULL ); + + for ( r = context->lc_rule->lr_next; r; ) { + struct rewrite_rule *cr = r; + + r = r->lr_next; + rewrite_rule_destroy( &cr ); + } + + free( context->lc_rule ); + context->lc_rule = NULL; + + assert( context->lc_name != NULL ); + free( context->lc_name ); + context->lc_name = NULL; + + free( context ); + *pcontext = NULL; + + return 0; +} |