rewrite the getcwd part

Also fixes a possible memory leak. Still not ideal, as seems CWD
longer than MAX_PATH is still not supported. But a heap allocation
is not needed anyway, as MAXPATHLEN value is the maximum supported.

Author: weltling

Zend/zend_virtual_cwd.c

@@ -328,32 +328,19 @@ CWD_API int php_sys_stat_ex(const char *path, zend_stat_t *buf, int lstat) /* {{
 		buf->st_dev = buf->st_rdev = 0;
 	} else {
 		wchar_t cur_path[MAXPATHLEN+1];
-		DWORD len = sizeof(cur_path);
-		wchar_t *tmp = cur_path;
-
-		while(1) {
-			DWORD r = GetCurrentDirectoryW(len, tmp);
-			if (r < len) {
-				if (tmp[1] == L':') {
-					if (pathw[0] >= L'A' && pathw[0] <= L'Z') {
-						buf->st_dev = buf->st_rdev = pathw[0] - L'A';
-					} else {
-						buf->st_dev = buf->st_rdev = pathw[0] - L'a';
-					}
+
+		if (NULL != _wgetcwd(cur_path, sizeof(cur_path)/sizeof(wchar_t))) {
+			if (cur_path[1] == L':') {
+				if (pathw[0] >= L'A' && pathw[0] <= L'Z') {
+					buf->st_dev = buf->st_rdev = pathw[0] - L'A';
 				} else {
-					buf->st_dev = buf->st_rdev = -1;
+					buf->st_dev = buf->st_rdev = pathw[0] - L'a';
 				}
-				break;
-			} else if (!r) {
-				buf->st_dev = buf->st_rdev = -1;
-				break;
 			} else {
-				len = r+1;
-				tmp = (wchar_t*)malloc(len*sizeof(wchar_t));
+				buf->st_dev = buf->st_rdev = -1;
 			}
-		}
-		if (tmp != cur_path) {
-			free(tmp);
+		} else {
+			buf->st_dev = buf->st_rdev = -1;
 		}
 	}