Please stop using CMD.EXE on the exec() function

The use of CMD.EXE in the calls to exec() under Windows isn't needed and in fact causes all sorts of problems - I've argued the case quite successfully for G1 (as it's been removed), so why is it still in G2?

I couldn't get G2 to accept that Imagemagick was installed correctly on my system until I discovered this, and once removed everything worked. The code snippet I changed in WinNtPlatform.class now looks like:

	/*
	 * Ok, this is screwy, but for some reason these
	 * don't work:
	 *
	 *    cmd /c "c:\path with\spaces\binary" "arg"
	 *    cmd /c " c:\path\\ with\spaces\binary arg "
	 *    cmd /c " 'c:\path\ with\spaces\binary' 'arg' "
	 *
	 * But this does:
	 *
	 *    cmd /c " "c:\path with\spaces\binary" "arg" "
	 *
	 * Turns out that this is a documented feature of cmd.exe.
	 * See "cmd.exe /help" for more details
	 *
	 */
	// ***** $command = 'cmd /c "' . $command . ' 2> "' . $debugFile . '" "';
	$command = '"' . $command . '"';

	if ($gallery->getDebug()) {
	    $gallery->debug("Executing: $command");
	}
	$results = array();
	exec($command, $results, $status);

	// *****
	if ($gallery->getDebug()) {
	    $gallery->debug("Results: " . print_r($results,true));
	}

	list ($ret, $expected) =
	    GalleryCoreApi::getPluginParameter('module', 'core', 'exec.expectedStatus');
	if ($ret->isError()) {
	    if ($gallery->getDebug()) {
		$gallery->debug('Unable to look up core.exec.expectedStatus param');
	    }
	    $expected = 0;
	}

My changes marked with // *****

----

Gallery URL (optional): http://gallery2.star-one.co.uk
Gallery version: G2b1
Webserver (with version): IIS 6
Datatabase (with version): MySQL v4.1.10a
PHP version (eg 4.2.1): 5.0.3
phpinfo URL (optional):
Graphics Toolkit(s): Imagemagick v6.2.0
Operating system: Windows 2003 Server
Web browser/version: Firefox v1.0.1 & IE 6
G1 version (for migration bugs): v1.5 RC2

It's still in G2 because G2 forked off before G1.4.3

I believe that I did it this way initially for compatibility with older versions of Windows. Now I'm afraid to touch it! But you're right, we should revisit this. Would you start by filing this as a bug on sf.net and referencing this thread so that it doesn't get forgotten?

Also, I think that we should make up some kind of short PHP test script that exercises exec on a variety of command/argument sets with special characters in them (spaces, double and single quotes, etc) which we can then test out on a wide range of Windows to figure out whether this is going to cause us problems or not.

I can say that the current code does not cause me any problems on WinXP (possibly because I don't run Apache as a service, though).

Taomyn, I tried applying your fix to Beta 3: Bingo, without success. Would you mind trying this fix on that version as well? And, do you have any other pointers for IIS6/PHP + G2 installs?

h0bbel,

Don't know if this is helpful, but it looks if the code below is working for me on win2k/iis5.
Clearly this doesn't work for any path/filename with spaces. And can have a lot of other drawbacks, which I don't see. (It my first line of php code ever... :P )
I'll hope this wil help you in any way

    * Turns out that this is a documented feature of cmd.exe.
	 * See "cmd.exe /help" for more details
	 *
	 */
/* $command = 'cmd /c "' . $command . ' 2> "' . $debugFile . '" "'; */

    $command = str_replace('"',"  ", $command);
    $command = ($command . ' > ' . $debugFile);

buut, interesting. I'll have a look at that tonight.

Taomyn, sure, makes sense. But first try to get it working. h0bbel is writing IIS6/G2 docs at the moment and the cmd calls didn't work for him. So the first thing is to get it working, then we can refactor the code, if there's a need to.

Have you tried using Filemon from Sysinternals to monitor file activity? It will capture file accesses (filtered if need be) so you can see what the processes are trying to do. It's how I sorted this out before.

Also make sure to give the following security:

CMD.EXE - IUSR_computername & NETWORK SERVICE Read + Execute
PHP temp - IUSR_computername & NETWORK SERVICE Modify

Basically the two acounts, IUSR_computername & NETWORK SERVICE, are used various parts of IIS6 to access the rest of the server.

Oh, and unlike a few other recommendations I've seen, don't make a copy of CMD.EXE just for this - there's no need and any service packs will not update the executable you copy.

I can offer direct help on the server but that would require me to have full access via TS to the server to get to the bottom of why its not working :-?

Taomyn, i've used filemon, yes. I'll have a new stab at this during the weekend, and if i'm unable to sort it out, I'll be happy to provide you with TS access. My W2K3 box is running inside vmware anyway, and it's only used for this. Whatever you do, i can always revert to a snapshot.

buut, i'll post as soon as i've looked at it this weekend. I do suspect that there is something IIS6 specific though, but that might very well be my own fault.

No result. there's still a bug, but noone deems it important enough to take a look at it.

http://gallery.menalto.com/sfvote/vote/1163580