1 files changed, 510 insertions, 0 deletions
diff --git a/libraries/librewrite/rule.c b/libraries/librewrite/rule.c
new file mode 100644
index 0000000..c9eb2b4
--- /dev/null
+++ b/libraries/librewrite/rule.c
@@ -0,0 +1,510 @@
+/* $OpenLDAP$ */
+/* 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"
+
+/*
+ * Appends a rule to the double linked list of rules
+ * Helper for rewrite_rule_compile
+ */
+static int
+append_rule(
+		struct rewrite_context *context,
+		struct rewrite_rule *rule
+)
+{
+	struct rewrite_rule *r;
+
+	assert( context != NULL );
+	assert( context->lc_rule != NULL );
+	assert( rule != NULL );
+
+	for ( r = context->lc_rule; r->lr_next != NULL; r = r->lr_next );
+	r->lr_next = rule;
+	rule->lr_prev = r;
+	
+	return REWRITE_SUCCESS;
+}
+
+/*
+ * Appends an action to the linked list of actions
+ * Helper for rewrite_rule_compile
+ */
+static int
+append_action(
+		struct rewrite_action **pbase,
+		struct rewrite_action *action
+)
+{
+	struct rewrite_action **pa;
+
+	assert( pbase != NULL );
+	assert( action != NULL );
+	
+	for ( pa = pbase; *pa != NULL; pa = &(*pa)->la_next );
+	*pa = action;
+	
+	return REWRITE_SUCCESS;
+}
+
+static int
+destroy_action(
+		struct rewrite_action **paction
+)
+{
+	struct rewrite_action	*action;
+
+	assert( paction != NULL );
+	assert( *paction != NULL );
+
+	action = *paction;
+
+	/* do something */
+	switch ( action->la_type ) {
+	case REWRITE_FLAG_GOTO:
+	case REWRITE_FLAG_USER: {
+		int *pi = (int *)action->la_args;
+
+		if ( pi ) {
+			free( pi );
+		}
+		break;
+	}
+
+	default:
+		break;
+	}
+	
+	free( action );
+	*paction = NULL;
+	
+	return 0;
+}
+
+static void
+destroy_actions(
+	struct rewrite_action *paction
+)
+{
+	struct rewrite_action *next;
+
+	for (; paction; paction = next) {
+		next = paction->la_next;
+		destroy_action( &paction );
+	}
+}
+
+/*
+ */
+int
+rewrite_rule_compile(
+		struct rewrite_info *info,
+		struct rewrite_context *context,
+		const char *pattern,
+		const char *result,
+		const char *flagstring
+)
+{
+	int flags = REWRITE_REGEX_EXTENDED | REWRITE_REGEX_ICASE;
+	int mode = REWRITE_RECURSE;
+	int max_passes;
+
+	struct rewrite_rule *rule = NULL;
+	struct rewrite_subst *subst = NULL;
+	struct rewrite_action *action = NULL, *first_action = NULL;
+
+	const char *p;
+
+	assert( info != NULL );
+	assert( context != NULL );
+	assert( pattern != NULL );
+	assert( result != NULL );
+	/*
+	 * A null flagstring should be allowed
+	 */
+
+	max_passes = info->li_max_passes_per_rule;
+
+	/*
+	 * Take care of substitution string
+	 */
+	subst = rewrite_subst_compile( info, result );
+	if ( subst == NULL ) {
+		return REWRITE_ERR;
+	}
+
+	/*
+	 * Take care of flags
+	 */
+	for ( p = flagstring; p[ 0 ] != '\0'; p++ ) {
+		switch( p[ 0 ] ) {
+			
+		/*
+		 * REGEX flags
+		 */
+		case REWRITE_FLAG_HONORCASE: 		/* 'C' */
+			/*
+			 * Honor case (default is case insensitive)
+			 */
+			flags &= ~REWRITE_REGEX_ICASE;
+			break;
+			
+		case REWRITE_FLAG_BASICREGEX: 		/* 'R' */
+			/*
+			 * Use POSIX Basic Regular Expression syntax
+			 * instead of POSIX Extended Regular Expression 
+			 * syntax (default)
+			 */
+			flags &= ~REWRITE_REGEX_EXTENDED;
+			break;
+			
+		/*
+		 * Execution mode flags
+		 */
+		case REWRITE_FLAG_EXECONCE: 		/* ':' */
+			/*
+			 * Apply rule once only
+			 */
+			mode &= ~REWRITE_RECURSE;
+			mode |= REWRITE_EXEC_ONCE;
+			break;
+		
+		/*
+		 * Special action flags
+		 */
+		case REWRITE_FLAG_STOP:	 		/* '@' */
+			/*
+			 * Bail out after applying rule
+			 */
+			action = calloc( sizeof( struct rewrite_action ), 1 );
+			if ( action == NULL ) {
+				goto fail;
+			}
+
+			action->la_type = REWRITE_ACTION_STOP;
+			break;
+			
+		case REWRITE_FLAG_UNWILLING: 		/* '#' */
+			/*
+			 * Matching objs will be marked as gone!
+			 */
+			action = calloc( sizeof( struct rewrite_action ), 1 );
+			if ( action == NULL ) {
+				goto fail;
+			}
+			
+			mode &= ~REWRITE_RECURSE;
+			mode |= REWRITE_EXEC_ONCE;
+			action->la_type = REWRITE_ACTION_UNWILLING;
+			break;
+
+		case REWRITE_FLAG_GOTO:				/* 'G' */
+			/*
+			 * After applying rule, jump N rules
+			 */
+
+		case REWRITE_FLAG_USER: {			/* 'U' */
+			/*
+			 * After applying rule, return user-defined
+			 * error code
+			 */
+			char *next = NULL;
+			int *d;
+			
+			if ( p[ 1 ] != '{' ) {
+				goto fail;
+			}
+
+			d = malloc( sizeof( int ) );
+			if ( d == NULL ) {
+				goto fail;
+			}
+
+			d[ 0 ] = strtol( &p[ 2 ], &next, 0 );
+			if ( next == &p[ 2 ] || next[0] != '}' ) {
+				free( d );
+				goto fail;
+			}
+
+			action = calloc( sizeof( struct rewrite_action ), 1 );
+			if ( action == NULL ) {
+				free( d );
+				goto fail;
+			}
+			switch ( p[ 0 ] ) {
+			case REWRITE_FLAG_GOTO:
+				action->la_type = REWRITE_ACTION_GOTO;
+				break;
+
+			case REWRITE_FLAG_USER:
+				action->la_type = REWRITE_ACTION_USER;
+				break;
+
+			default:
+				assert(0);
+			}
+
+			action->la_args = (void *)d;
+
+			p = next;	/* p is incremented by the for ... */
+		
+			break;
+		}
+
+		case REWRITE_FLAG_MAX_PASSES: {			/* 'U' */
+			/*
+			 * Set the number of max passes per rule
+			 */
+			char *next = NULL;
+			
+			if ( p[ 1 ] != '{' ) {
+				goto fail;
+			}
+
+			max_passes = strtol( &p[ 2 ], &next, 0 );
+			if ( next == &p[ 2 ] || next[0] != '}' ) {
+				goto fail;
+			}
+
+			if ( max_passes < 1 ) {
+				/* FIXME: nonsense ... */
+				max_passes = 1;
+			}
+
+			p = next;	/* p is incremented by the for ... */
+		
+			break;
+		}
+
+		case REWRITE_FLAG_IGNORE_ERR:               /* 'I' */
+			/*
+			 * Ignore errors!
+			 */
+			action = calloc( sizeof( struct rewrite_action ), 1 );
+			if ( action == NULL ) {
+				goto fail;
+			}
+			
+			action->la_type = REWRITE_ACTION_IGNORE_ERR;
+			break;
+			
+		/*
+		 * Other flags ...
+		 */
+		default:
+			/*
+			 * Unimplemented feature (complain only)
+			 */
+			break;
+		}
+		
+		/*
+		 * Stupid way to append to a list ...
+		 */
+		if ( action != NULL ) {
+			append_action( &first_action, action );
+			action = NULL;
+		}
+	}
+	
+	/*
+	 * Finally, rule allocation
+	 */
+	rule = calloc( sizeof( struct rewrite_rule ), 1 );
+	if ( rule == NULL ) {
+		goto fail;
+	}
+	
+	/*
+	 * REGEX compilation (luckily I don't need to take care of this ...)
+	 */
+	if ( regcomp( &rule->lr_regex, ( char * )pattern, flags ) != 0 ) {
+		goto fail;
+	}
+	
+	/*
+	 * Just to remember them ...
+	 */
+	rule->lr_pattern = strdup( pattern );
+	rule->lr_subststring = strdup( result );
+	rule->lr_flagstring = strdup( flagstring );
+	if ( rule->lr_pattern == NULL
+		|| rule->lr_subststring == NULL
+		|| rule->lr_flagstring == NULL )
+	{
+		goto fail;
+	}
+	
+	/*
+	 * Load compiled data into rule
+	 */
+	rule->lr_subst = subst;
+
+	/*
+	 * Set various parameters
+	 */
+	rule->lr_flags = flags;		/* don't really need any longer ... */
+	rule->lr_mode = mode;
+	rule->lr_max_passes = max_passes;
+	rule->lr_action = first_action;
+	
+	/*
+	 * Append rule at the end of the rewrite context
+	 */
+	append_rule( context, rule );
+
+	return REWRITE_SUCCESS;
+
+fail:
+	if ( rule ) {
+		if ( rule->lr_pattern ) free( rule->lr_pattern );
+		if ( rule->lr_subststring ) free( rule->lr_subststring );
+		if ( rule->lr_flagstring ) free( rule->lr_flagstring );
+		free( rule );
+	}
+	destroy_actions( first_action );
+	free( subst );
+	return REWRITE_ERR;
+}
+
+/*
+ * Rewrites string according to rule; 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_rule_apply(
+		struct rewrite_info *info,
+		struct rewrite_op *op,
+		struct rewrite_rule *rule,
+		const char *arg,
+		char **result
+		)
+{
+	size_t nmatch = REWRITE_MAX_MATCH;
+	regmatch_t match[ REWRITE_MAX_MATCH ];
+
+	int rc = REWRITE_SUCCESS;
+
+	char *string;
+	int strcnt = 0;
+	struct berval val = { 0, NULL };
+
+	assert( info != NULL );
+	assert( op != NULL );
+	assert( rule != NULL );
+	assert( arg != NULL );
+	assert( result != NULL );
+
+	*result = NULL;
+
+	string = (char *)arg;
+	
+	/*
+	 * In case recursive match is required (default)
+	 */
+recurse:;
+
+	Debug( LDAP_DEBUG_TRACE, "==> rewrite_rule_apply"
+			" rule='%s' string='%s' [%d pass(es)]\n", 
+			rule->lr_pattern, string, strcnt + 1 );
+	
+	op->lo_num_passes++;
+
+	rc = regexec( &rule->lr_regex, string, nmatch, match, 0 );
+	if ( rc != 0 ) {
+		if ( *result == NULL && string != arg ) {
+			free( string );
+		}
+
+		/*
+		 * No match is OK; *result = NULL means no match
+		 */
+		return REWRITE_REGEXEC_OK;
+	}
+
+	rc = rewrite_subst_apply( info, op, rule->lr_subst, string,
+			match, &val );
+
+	*result = val.bv_val;
+	val.bv_val = NULL;
+	if ( string != arg ) {
+		free( string );
+		string = NULL;
+	}
+
+	if ( rc != REWRITE_REGEXEC_OK ) {
+		return rc;
+	}
+
+	if ( ( rule->lr_mode & REWRITE_RECURSE ) == REWRITE_RECURSE 
+			&& op->lo_num_passes < info->li_max_passes
+			&& ++strcnt < rule->lr_max_passes ) {
+		string = *result;
+
+		goto recurse;
+	}
+
+	return REWRITE_REGEXEC_OK;
+}
+
+int
+rewrite_rule_destroy(
+		struct rewrite_rule **prule
+		)
+{
+	struct rewrite_rule *rule;
+
+	assert( prule != NULL );
+	assert( *prule != NULL );
+
+	rule = *prule;
+
+	if ( rule->lr_pattern ) {
+		free( rule->lr_pattern );
+		rule->lr_pattern = NULL;
+	}
+
+	if ( rule->lr_subststring ) {
+		free( rule->lr_subststring );
+		rule->lr_subststring = NULL;
+	}
+
+	if ( rule->lr_flagstring ) {
+		free( rule->lr_flagstring );
+		rule->lr_flagstring = NULL;
+	}
+
+	if ( rule->lr_subst ) {
+		rewrite_subst_destroy( &rule->lr_subst );
+	}
+
+	regfree( &rule->lr_regex );
+
+	destroy_actions( rule->lr_action );
+
+	free( rule );
+	*prule = NULL;
+
+	return 0;
+}
+