Re: [Expectperl-discuss] Help with legacy expect code

[mike n. <xmi...@gm...>]

Hi Mr. McGowan,

Just a shot in the dark, but:

# instead of this:
##################

  $ssh->expect(0, '-re', "$pat");
  $ssh->log_file(\&logMethod) if $logging;
         return $ssh->error();
     };

# You may want to try:
######################

  $ssh->expect(5,
        [ '-re', $pat => sub {  $ssh->log_file(\&logMethod) if $logging;
                                return $ssh->error();
                                  }],

        ['-re', $contains_stuff => sub { break;
                                   }],
        );

Maybe try setting $contains_stuff to something you would expect on success
i.e. no pw being echo'd back ?

On Fri, Mar 24, 2017 at 4:52 PM, Bob McGowan <ram...@gm...> wrote:

> Hello List,
>
> I'm supporting legacy code that uses Expect, but I'm no expert with this
> tool.  Nor can I figure out a way to pose the question to the archive
> server to search for anything helpful, so here I am, hoping for an answer.
> :)
>
> Before the section that does the Expect processing, there is a sub defined
> as follows:
>
>     $passHandler = sub {
>         my ($ssh, $logging, $password) = @_;
>         $ssh->log_file(undef);
>         $ssh->stty(qw(-echo));
>         print $ssh "$password\r";
>         $ssh->stty(qw(echo));
>         $pat = quotemeta($password);
>
>         $ssh->expect(0, '-re', "$pat");
>
>         $ssh->log_file(\&logMethod) if $logging;
>         return $ssh->error();
>     };
>
> There are a number of other patterns to look for besides the two prompts
> listed below, each with appropriate logic contained in other 'sub'
> definitions.  My problem is with the second prompt.  Also, I'm not being
> pedantic here about format or syntax, this is not intended to run
> (currently).
>
>     $expectObj->expect($timeout,
>             '-re', $prompt1, sub {
>                 $failed = $passHandler->($ssh, $logging, $password);
>                 if ($failed) {
>                     return "something";
>                 } else {
>                     return exp_continue_timeout();
>                 }
>             },
>             '-re', $prompt2, sub {
>                 $output = $ssh->exp_before();
>                 if ($secondPass) {
>                     $failed = $passHandler->($ssh, $logging, $secondPass);
>                     if ($failed) {
>                         return 'something';
>                     } else {
>                         return exp_continue_timeout();
>                     }
>                 } else {
>                     return # an error
>                 }
>             },
>             ...
>         );
>
> I have run the original code with debugging on.
>
> Processing $prompt1 happens before processing for $prompt2.  $prompt1 is
> the login prompt passed through by 'ssh'.
>
> Handling the ssh login step works fine.
>
> Processing the second prompt looks for a string like 'Enter secondary
> password: ' which is detected correctly and processing goes into the
> passHandler, where the password is sent.
>
> The function then does the 'expect' on the password "pattern", which is
> there to be sure we don't get any echo'ed password passed through.
>
> But in the failing case, there is no password echoed, and the next set of
> returned strings contains stuff that doesn't match, within the
> passHandler.  So it times out.
>
> Upon returning to the enclosing 'expect' call, expect immediately begins
> 'waiting' for new data.  The strings that were picked up in passHandler are
> not looked at, and unfortunately they have the next string being 'waited'
> for, so the whole thing times out and processing fails.
>
> I'm happy to try to make something that actually runs, if that is needed,
> but that will take a bit more time and I hope this is enough to point
> someone in the right direction.
>
> Many thanks,
>
> Bob
>
>
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