[horde] VFS ssh2 _listFolder() buglet?

[Lawrence Stewart]

Hi Benedetto,

On 01/07/11 09:44, Benedetto Vassallo wrote:
> 
> Def. Quota Lawrence Stewart <lstewart at room52.net>:
> 
>> Hi all,
>>
>> Whilst switching my Gollem config over to using the ssh2 backend, I
>> think I've found a bug in the ssh2 VFS code. I got the Gollem config to
>> the point where I could successfully upload files, but the directory
>> listing would always claim the directory to be empty without any sort of
>> error logged in the horde log file.
>>
>> After a bit of sleuthing, I tracked the offending line of code to:
>>
>> $stream = @ssh2_exec($this->_stream, 'LC_TIME=C ls -' . $ls_args . ' ' .
>> escapeshellarg($path));
>>
>> (Horde v3.3.11, line 489 of lib/VFS/ssh2.php)
>>
>> I use FreeBSD as the server OS and tcsh as my shell. Prefixing the
>> command with an ENV=VAR assignment only works on Bourne type shells. It
>> seems the sftp server on FreeBSD runs the command in the context of the
>> user's selected shell as opposed to /bin/sh, because the offending line
>> produces no output as a result of the command failing.
>>
>> My solution fixes the problem for me and I believe is more correct than
>> the current code. By prefixing the ls command with "env", all shells
>> including tcsh are happy i.e.:
>>
>> $stream = @ssh2_exec($this->_stream, 'env LC_TIME=C ls -' . $ls_args . '
>> ' . escapeshellarg($path));
>>
>> Prefixing with env allows everything to work perfectly for me.
>>
>> Does the above seem reasonable or have I misunderstood something? I'll
>> file a bug report with the patch if people think my analysis is correct.
>>
>> Cheers,
>> Lawrence
>>
>> PS: I haven't looked, but I suspect there could be instances of other
>> such problems in the tree. It would be useful to do an audit of command
>> lines run by horde to look for others which set env vars in the same
>> manner as the above code.
> 
> Hello,
> As a feedback I use Horde 3.3.11 and gollem 1.1.2 on CentOs 5.5, php
> 5.1.6, bash shell and ssh2 backend works fine for me.

Thanks for the data point. I would expect this to be the case given that
bash is a Bourne-like shell and happily runs 'ENV=VAR command'. What
would be interesting to know is if a csh derivative shell on Linux
encounters the same issue I'm seeing.

Do you feel like trying a quick little experiment of temporarily
changing your shell with the chsh command to csh or tcsh and seeing if
gollem fails to give you a directory listing back? If you have
"'createhome' => true" set in your ssh2 backend for Gollem, you will get
an error along the lines of "Cannot create home dir" when you try click
on your Gollem vdir. This is because the dir listing fails, so it thinks
it needs to create the homedir which already exists, and it propagates
the failure to create the dir up to horde which effectively blocks
access to your vdir. If you see that error or you have "'createhome' =>
false" and get an empty dir listing when you know files should be
listed, try switching your shell back to bash and confirm everything
comes good again.

That aside, my proposed change is harmless for people running sh/bash so
I don't see a reason not to make the change. I'm still curious to know
the outcome of the above experiment on a Linux system.

Cheers,
Lawrence