proc_openとパイプを使用して、ファイルを tar の stdin にストリーミングできます。これはphp.netからのわずかに適応した例です
$descriptorspec = array(
0 => array("pipe", "r"), // stdin is a pipe that the child will read from
1 => array("pipe", "w"), // stdout is a pipe that the child will write to
2 => array("file", "/tmp/error-output.txt", "a") // stderr is a file to write to
);
$process = proc_open('tar xz', $descriptorspec, $pipes, __DIR__, $env);
if (is_resource($process)) {
// $pipes now looks like this:
// 0 => writeable handle connected to child stdin
// 1 => readable handle connected to child stdout
// Any error output will be appended to /tmp/error-output.txt
fwrite($pipes[0], $tar_gz_string);
fclose($pipes[0]);
echo stream_get_contents($pipes[1]);
fclose($pipes[1]);
proc_close($process);
}