Description:
------------
Version: yp-0.1.0-dev
The PHP functions yp_match, yp_first, yp_next do not free the pointer variables outval and outkey, set by the OS functions of the same names as the PHP functions. These pointers should be freed on returning from the PHP functions.
(Well, for a few calls in CGI mode this may be irrelevant, but not in FastCGI or mod_php modes.)
Also, some maps (e.g., mail.aliases) may contain keys ending in a zero byte. These should be handled in yp_match by trying a second call to the OS function yp_match with a key length incremented by one (as does the OS command "ypmatch", see code of ypmatch.c from [e.g.] OpenSolaris).
A patch for yp.c is given below (output of diff -u).

Reproduce code:
---------------
--- yp.c.orig	Tue Dec  9 12:09:19 2008
+++ yp.c	Fri Dec 10 10:33:28 2010
@@ -146,7 +146,7 @@
 PHP_FUNCTION(yp_match)
 {
 	pval **domain, **map, **key;
-	char *outval;
+	char *outval=NULL;
 	int outvallen;
 
 	if((ZEND_NUM_ARGS() != 3) || zend_get_parameters_ex(3,&domain,&map,&key) == FAILURE) {
@@ -157,12 +157,22 @@
 	convert_to_string_ex(map);
 	convert_to_string_ex(key);
 
-	if((YP(error) = yp_match(Z_STRVAL_PP (domain), Z_STRVAL_PP (map), Z_STRVAL_PP (key), Z_STRLEN_PP (key), &outval, &outvallen))) {
+	YP(error) = yp_match(Z_STRVAL_PP (domain), Z_STRVAL_PP (map), Z_STRVAL_PP (key), Z_STRLEN_PP (key), &outval, &outvallen);
+	if(YP(error) == YPERR_KEY) {
+	    if(outval != NULL) {
+		free(outval);
+		outval = NULL;
+	    }
+	    YP(error) = yp_match(Z_STRVAL_PP (domain), Z_STRVAL_PP (map), Z_STRVAL_PP (key), Z_STRLEN_PP (key)+1, &outval, &outvallen);
+	}
+	if(YP(error)) {
+		if(outval != NULL) free(outval);
 		php_error_docref(NULL TSRMLS_CC, E_WARNING, "%s", yperr_string (YP(error)));
 		RETURN_FALSE;
 	}
 
 	RETVAL_STRINGL(outval,outvallen,1);
+	free(outval);
 }
 /* }}} */
 
@@ -171,7 +181,7 @@
 PHP_FUNCTION(yp_first)
 {
 	pval **domain, **map;
-	char *outval, *outkey;
+	char *outval=NULL, *outkey=NULL;
 	int outvallen, outkeylen;
 
 	if((ZEND_NUM_ARGS() != 2) || zend_get_parameters_ex(2,&domain,&map) == FAILURE) {
@@ -182,6 +192,8 @@
 	convert_to_string_ex(map);
 
 	if((YP(error) = yp_first(Z_STRVAL_PP (domain), Z_STRVAL_PP (map), &outkey, &outkeylen, &outval, &outvallen))) {
+		if(outval != NULL) free(outval);
+		if(outkey != NULL) free(outkey);
 		php_error_docref(NULL TSRMLS_CC, E_WARNING, "%s", yperr_string (YP(error)));
 		RETURN_FALSE;
 	}
@@ -191,6 +203,8 @@
 	/* Deprecated */
 	add_assoc_stringl(return_value,"key",outkey,outkeylen,1);
 	add_assoc_stringl(return_value,"value",outval,outvallen,1);
+	free(outval);
+	free(outkey);
 }
 /* }}} */
 
@@ -199,7 +213,7 @@
 PHP_FUNCTION(yp_next)
 {
 	pval **domain, **map, **key;
-	char *outval, *outkey;
+	char *outval=NULL, *outkey=NULL;
 	int outvallen, outkeylen;
 
 	if((ZEND_NUM_ARGS() != 3) || zend_get_parameters_ex(3,&domain,&map,&key) == FAILURE) {
@@ -211,6 +225,8 @@
 	convert_to_string_ex(key);
 
 	if((YP(error) = yp_next(Z_STRVAL_PP (domain), Z_STRVAL_PP (map), Z_STRVAL_PP (key), Z_STRLEN_PP (key), &outkey, &outkeylen, &outval, &outvallen))) {
+		if(outval != NULL) free(outval);
+		if(outkey != NULL) free(outkey);
 		php_error_docref(NULL TSRMLS_CC, E_WARNING, "%s", yperr_string (YP(error)));
 		RETURN_FALSE;
 	}
@@ -217,6 +233,8 @@
 	
 	array_init(return_value);
 	add_assoc_stringl_ex(return_value,outkey,outkeylen+1,outval,outvallen,1);
+	free(outval);
+	free(outkey);
 }
 /* }}} */