php exec: does not return output

Question

I have this problem: On a ISS web server, windows 7 x64 professional, zend server installed. Running this command under php:

exec(\'dir\',$output, $err);


        

Answer 1

I know I have choosen an answer as I must do it but I still do not understand why it wont work on my macchine but I found a fallback (using proc_open) solution using another method:

public static function exec_alt($cmd)
{
    exec($cmd, $output);
    if (!$output) {
        /**
         * FIXME: for some reason exec() returns empty output array @mine,'s machine.
         *        Somehow proc_open() approach (below) works, but doesn't work at
         *        test machines - same empty output with both pipes and temporary
         *        files (not we bypass shell wrapper). So use it as a fallback.
         */
        $output = array();
        $handle = proc_open($cmd, array(1 => array('pipe', 'w')), $pipes, null, null, array('bypass_shell' => true));
        if (is_resource($handle)) {
            $output = explode("\n", stream_get_contents($pipes[1]));
            fclose($pipes[1]);
            proc_close($handle);
        }
    }
    return $output;
}

Hope this helps someone.

Answer 2

Take a look at Apache error_log, maybe you'll find the error message.

Also, you can try using popen instead of exec. It gives more control because you can separate process start from output read:

$p = popen("dir", "r");
if (!$p)
    exit("Cannot run command.\n");
while (!feof($p))
    echo fgets($p);
pclose($p);

Answer 3

Try this:

shell_exec('dir 2>&1');

It works fine on Windows 8.1 64bits with UAC enabled.

Answer 4

You can check permisssions of IIS User to cmd.exe

cacls C:\WINDOWS\system32\cmd.exe

If in output is line like (COMPUTERNAME=your computer name):

C:\WINDOWS\system32\cmd.exe COMPUTERNAME\IUSR_COMPUTERNAME:N

It means that user has no rights to execute cmd.

You can add execute permissions with command:

cacls C:\WINDOWS\system32\cmd.exe /E /G COMPUTERNAME\IUSR_COMPUTERNAME:R