SSH Path Bug

[Larry Hall]

At 05:55 AM 5/1/2005, you wrote:
>On Apr 30 14:53, Larry Hall wrote:
>> At 09:59 PM 4/29/2005, you wrote:
>> >Dominic Chambers wrote:
>> >
>> >> Running commands via SSH causes windows executables to be given path
>> >> priority, so that they run ahead of identically named UNIX executables. I
>> >> found this while trying to use the find command as part of an SSH call.
>> >> For example, assuming you have an SSH server set up:
>> >
>> >I would think this has more to do with how you set your path than
>> >anything else.  [...]
>> 
>> No, it's not that.  I was able to reproduce the described behavior even 
>> when my system path has Cygwin's bin path before Windows.
>
>Sounds more like a cockpit error.  I just tried it and I can't reproduce it.


Yeah, it looks like I must have been caught by Windows' insufferable need
to be rebooted after almost any change.  Why am I surprised? ;-)


>> Running 'sshd'
>> in debug mode showed the imported path that was not an exact match to any
>> path I'd set anywhere.  So far, I haven't been able to get far enough 
>> that I know why this happens.  But I can say that it happens for me
>> and on more than 1 system and O/S.

I should have said "Windows O/S" here.  Specifically, I tried it on W2K and
XP.

>It's not a bug, it's a feature :-)
>
>What happens is a combination of what's done in cygrunsrv and sshd.
>
>First, cygrunsrv adds the path to /bin to the environment before starting
>a child process.  But it *appends* /bin to the path, so that the order
>of path evaluation isn't changed.  So that can be taken out of the equation.
>
>And what does sshd?  Sshd is equivalent to a login process, so on non-Cygwin
>systems, it has to set the PATH variable to the default path value for the
>system.  Usually something like PATH="/usr/bin:/bin".
>
>On Windows it's a bit different because the PATH variable given to service
>process (== the system environment) already contains paths, which are
>required to run any process on Windows.  So the PATH variable must not be
>replaced by default paths as on other systems.  Consequentially, Cygwin-sshd
>does not change $PATH at all, but uses the default PATH as it is set in the
>Windows system environment.  This is, IMHO, the equivalent to the default
>PATH on other systems.
>
>What you can do: 
>
>- Prepend Cygwin paths to your system environment and restart(!) the PC.


As I said above, UGH! ;-)


>- Set the default PATH only for your sshd service, for instance
>
>    cygrunsrv -I sshd -d "CYGWIN sshd" -p /usr/sbin/sshd -a -D \
>              -e "PATH=/usr/bin:/bin:/cygdrive/c/WINDOWS/system32:/cygdrive/c/WINDOWS:/cygdrive/c/WINDOWS/System32/Wbem"
>
>  assuming your Windows is installed in C:\Windows


Yeah, this is probably the nicest from the user point of view.


>- Even better: Always use absolute paths when running remote applications.


Yep.  That certainly works and is the most portable. :-)

Thanks.


--
Larry Hall                              http://www.rfk.com
RFK Partners, Inc.                      (508) 893-9779 - RFK Office
838 Washington Street                   (508) 893-9889 - FAX
Holliston, MA 01746                     


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