From: "Ara.T.Howard" <ahoward@...>
Date: 2004-04-15T15:49:25+09:00
Subject: Re: ruby pty/expect help

On Thu, 15 Apr 2004 nobu.nokada@softhome.net wrote:

> Hi,
> 
> At Thu, 15 Apr 2004 12:09:12 +0900,
> Ara.T.Howard wrote in [ruby-talk:97212]:
> > perhaps a handle on an object which can be 'closed' could be returned instead
> > of an array of Files, etc:
> > 
> >   passphrase = gen_random_passphrase
> > 
> >   pty = PTY.spawn 'ssh-keygen'
> > 
> >   pty.stdin.puts 'id_rsa.pub' 
> >   pty.stdin.puts passphrase
> >   pty.stdin.puts passphrase
> >   pts.close  # do the right thing
> 
> Yes, I've thought about same strategy for open3.


have you seen my session-2.1.6 package which wraps open3 in this way?  it is
more specific but same idea...

> ssh-agent doesn't read passphrase but prints some environment variables and
> runs as a daemon, like as:

right, right... i've slept three hourse in the last 48...  basically i'm just
trying to get around security ;-)

> 
>   $ ssh-agent
>   SSH_AUTH_SOCK=/tmp/ssh-FGmutb8164/agent.8164; export SSH_AUTH_SOCK;
>   SSH_AGENT_PID=8165; export SSH_AGENT_PID;
>   echo Agent pid 8165;
> 
> Therefore you should set those variables instead. e.g.,
> 
>   `ssh-agent`.scan(/^(SSH_[A-Z_]+)=([^; ]*)/, &ENV.method(:[]=))

                                                ^
                                                ^
                                                ^

                                              i learn something every day
                                              i guess that makes it a
                                              block - neat.



> 
> Then, you'll need to send passphrase to ssh-add.  At this time,
> you have 2 methods:
> 
> 1) with pty.
>     PTY.spawn("ssh-add") do |r,w,pid|
>       r.expect %r/^Enter.*:\s+/ {w.puts passphrase}
>     end
> 
> 2) without control terminal.  Since ssh-add reads passphrase
>    from stdin when no ctty or X are available, you can:
> 
>     IO.popen("-", "w") do |f|
>       if f
>         f.puts passphrase
>       else
>         ENV.delete("SSH_ASKPASS")
>         ENV.delete("DISPLAY")
>         Process.setsid
> 	exec("ssh-add")
>       end
>     end
> 
>    or, if setsid command is available and env command has -u option:
> 
>     IO.popen("env -u SSH_ASKPASS -u DISPLAY setsid ssh-add", "w") do |f|
>       f.puts passphrase
>     end
> 
> 


-a
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