Preserving argument splitting with SSH

[Greg Badros]

Lee Eakin <leakin at japh.itg.ti.com> writes:

> The arg splitting is not preserved because it is parsed once by the local
> shell, and then again by the shell on the remote system.  When the remote
> system's shell sees it the quotes are already gone.
> 
> Try this:
>     ssh gellar args foo bar \'baz bong\'
> or:
>     ssh gellar args foo bar "'baz bong'"
>  
>  I think you'll see it parses properly then.

Right; I don't think I'd written clearly enough: you do not always need
to run a shell at the remote end.  In my example, just exec'ing with the
appropriate argv and environment is sufficient.  I was wondering about
making ssh just Do The Right Thing (e.g., if there are no shell globs or
shell metacharacters it clearly can just exec).  Alternatively, perhaps
there could be an option to just make the remote side do an exec
directly rather than use a shell.

Thanks for the response, Lee.  And I apologize for not mentioning the
two possible solutions I had in mind.

Thanks,
Greg


>    -Lee
> 
> ---begin quoted text---
> > Delivered-To: openssh-unix-dev-list-93873 at mindrot.org
> > To: openssh-unix-dev at mindrot.org
> > Subject: Preserving argument splitting with SSH
> > From: Greg Badros <gjb at cs.washington.edu>
> > Date: 14 Dec 2000 19:11:56 -0800
> > X-Mailer: Gnus v5.6.45/XEmacs 20.4 - "Emerald"
> > 
> > I'm using:
> > 
> > % ssh -V
> > SSH Version OpenSSH-1.2.3, protocol version 1.5.
> > Compiled with SSL.
> > % uname -a
> > Linux gellar 2.2.13 #1 SMP Wed Dec 29 14:07:41 PST 1999 i686 unknown
> > 
> > and am wondering whether it's a fundamental shortcoming of the SSH
> > protocol that argument splitting is not preserved from client to server, 
> > but instead the argument list is re-split on whitespace.  E.g., from my
> > machine `gellar', I execute:
> > 
> > % ssh gellar args foo bar 'baz bong'
> > ARG0 = /usr/home/gregb/bin/share/args, NumArgs = 4
> > 1 = "foo"
> > 2 = "bar"
> > 3 = "baz"
> > 4 = "bong"
> > 
> > (where args is just a script that outputs the arguments), instead of
> > what I get when I run args directly:
> > 
> > % args foo bar 'baz bong'       
> > ARG0 = /usr/home/gregb/bin/share/args, NumArgs = 3
> > 1 = "foo"
> > 2 = "bar"
> > 3 = "baz bong"
> > 
> > which is much better.  If it's not a limitation of the protocol, then it 
> > should be a pretty easy (and valuable!) fix.
> > 
> > Please include me in replies as I'm not on the list.
> > 
> > Thanks,
> > Greg
> ---end quoted text---
> 
> -- 
>     Lee Eakin - leakin at ti.com - Naming Services, Texas Instruments   -o)
>                 [ permanent e-mail: Lee at Eakin.Org ]                  /\\
>                                                                     _\_v
> Allen's Axiom:
>   When all else fails, follow instructions.