Fix bug #81618: Correct dns_get_record on FreeBSD

Modify dns_get_record to test for records result based on dns_errno to
accommodate modern FreeBSD, for which res_nsearch() does not update
h_errno directly. Add new php_dns_errno macro, and have it consult
statp->res_h_errno when OS has res_nsearch().

Closes GH-7655.

Author: fsbruva

NEWS

@@ -9,6 +9,10 @@ PHP                                                                        NEWS
 - GD:
   . Fixed bug #71316 (libpng warning from imagecreatefromstring). (cmb)
 
+- Standard:
+  . Fixed bug #81618 (dns_get_record fails on FreeBSD for missing type).
+    (fsbruva)
+
 18 Nov 2021, PHP 7.4.26
 
 - Core:

ext/standard/dns.c

@@ -808,6 +808,7 @@ PHP_FUNCTION(dns_get_record)
 	zend_long type_param = PHP_DNS_ANY;
 	zval *authns = NULL, *addtl = NULL;
 	int type_to_fetch;
+	int dns_errno;
 #if defined(HAVE_DNS_SEARCH)
 	struct sockaddr_storage from;
 	uint32_t fromsize = sizeof(from);
@@ -957,8 +958,9 @@ PHP_FUNCTION(dns_get_record)
 			n = php_dns_search(handle, hostname, C_IN, type_to_fetch, answer.qb2, sizeof answer);
 
 			if (n < 0) {
+				dns_errno = php_dns_errno(handle);
 				php_dns_free_handle(handle);
-				switch (h_errno) {
+				switch (dns_errno) {
 					case NO_DATA:
 					case HOST_NOT_FOUND:
 						continue;

ext/standard/php_dns.h

@@ -26,6 +26,7 @@
     	((int)dns_search(res, dname, class, type, (char *) answer, anslen, (struct sockaddr *)&from, &fromsize))
 #define php_dns_free_handle(res) \
 		dns_free(res)
+#define php_dns_errno(handle) h_errno
 
 #elif defined(HAVE_RES_NSEARCH)
 #define php_dns_search(res, dname, class, type, answer, anslen) \
@@ -39,11 +40,13 @@
 			res_nclose(res); \
 			php_dns_free_res(res)
 #endif
+#define php_dns_errno(handle) handle->res_h_errno
 
 #elif defined(HAVE_RES_SEARCH)
 #define php_dns_search(res, dname, class, type, answer, anslen) \
 			res_search(dname, class, type, answer, anslen)
 #define php_dns_free_handle(res) /* noop */
+#define php_dns_errno(handle) h_errno
 
 #endif
 

ext/standard/tests/network/bug81618.phpt

@@ -0,0 +1,15 @@
+--TEST--
+Bug #81618: dns_get_record failure on FreeBSD
+--SKIPIF--
+<?php
+if (getenv('SKIP_ONLINE_TESTS')) die('skip online test');
+?>
+--FILE--
+<?php
+$ret = dns_get_record('www.google.com', DNS_A + DNS_CNAME);
+
+echo ($ret !== false && count($ret) > 0);
+
+?>
+--EXPECT--
+1