add test

Author: devnexen

ext/phar/tests/tar/gh21986.phpt

@@ -0,0 +1,43 @@
+--TEST--
+GH-21986 (PharData::getContent() crash on circular symlink chain in tar)
+--EXTENSIONS--
+phar
+--FILE--
+<?php
+function tar_symlink($name, $target) {
+    $h  = str_pad($name, 100, "\0");
+    $h .= "0000777\0";
+    $h .= "0000000\0";
+    $h .= "0000000\0";
+    $h .= "00000000000\0";
+    $h .= "00000000000\0";
+    $h .= str_repeat(' ', 8);
+    $h .= '2';
+    $h .= str_pad($target, 100, "\0");
+    $h .= "ustar\0" . "00";
+    $h  = str_pad($h, 512, "\0");
+
+    $sum = 0;
+    for ($i = 0; $i < 512; $i++) {
+        $sum += ord($h[$i]);
+    }
+    return substr_replace($h, sprintf("%06o\0 ", $sum), 148, 8);
+}
+
+$tar = __DIR__ . '/gh21986.tar';
+file_put_contents(
+    $tar,
+    tar_symlink('a.txt', 'b.txt') .
+    tar_symlink('b.txt', 'a.txt') .
+    str_repeat("\0", 1024)
+);
+
+$phar = new PharData($tar);
+var_dump($phar['a.txt']->getContent());
+?>
+--CLEAN--
+<?php
+@unlink(__DIR__ . '/gh21986.tar');
+?>
+--EXPECT--
+string(0) ""