Re: [Expectperl-discuss] Please point me to the right mailing list

[Roland G. <rgi...@cp...>]

Carlyle Sutphen wrote:
> Thank you for picking this up.
> 
> No, I can't install IO::Tty. I would have to justify rolling out non-standard packages on many
> hundreds of servers.

Comparing "rolling out a self-written custom script that probably 
doesn't has an automatic testsuite" to "installing a proven-in-use 
module" I fail to see the problem... :-) (don't flame me, I know, 
company policies... *sigh*)

> But if I can't get this to fly, I may look at PAR.

What I meant was installing the module in a private lib-dir. And yes, 
then you can package this up with PAR.

> I only need the slave side (pts) name. I'm sure it must be something simple. The rest
> works fine.

No, I don't think it can be done with pure perl. In C you have ptsname() 
for that purpose, but as it is not POSIX there is no standard perl 
binding to that that I am aware of (other than in IO::Tty).

Generally speaking, pty handling is a black magic and VERY system-dependent.

But come to think of, I have a nifty work-around! Use "ssh -t localhost 
cmd" to spawn the command with a terminal as stdin/out and interact with 
that via open2() or open3(). How does that sound?

Hope this helps,

Roland

> Here is the relevant code:
> 
> #!/usr/bin/perl -w
> use strict;
> use Fcntl; # Needed for O_RDWR and O_NOCTTY flags to sysopen
> use POSIX qw/setsid ttyname/;
> use POSIX ":sys_wait_h";
> #
> # Set up my variables and read the command line parameters.
> #
> # Open the control side and set non blocking
> sysopen( PTC, "/dev/ptc", O_RDWR | O_NOCTTY ) or die "Can't open a pseudo-terminal. $!";
> $s = select(PTC); $| = 1; select($s);
> # Get the name of the slave side

That won't work, you need ptsname() here. That this works in AIX is... 
well, I can't say non-standard, because there is no standard... :-)

> $ptyname = ttyname(fileno(PTC)) or die "Cannot get slave name: $?, $!\n";
> $pid = fork;
> if ($pid < 0) {
>  die "Can't fork: $1\n";
> }
> if( $pid == 0 ) { # I'm the son ; exec the program...
>   # Break away from the old controling terminal.
>   setsid() or die "Can't setsid: $!\n";
>   # Open the slave side of the new one and set non-blocking IO
>   sysopen( PTS, $ptyname, O_RDWR ) or die "Can't open a pseudo-terminal (child). $!";
>   $s = select(PTS); $| = 1; select($s);
>   close STDIN;
>   close STDOUT;
>   close STDERR;
>   open(STDIN,"<&PTS");
>   open(STDOUT,">&PTS");
>   open(STDERR,">&STDOUT");
>   $| = 1;
>   exec $prog-needing-tty;
> }
> $| = 1;
> while( sysread(PTC, $_, 1) ) {
>     print "$_";
>     $buf = $buf . $_;
>     #
>     # Check for specific string from child
>     # and send the correct responses.
>     #
>     if( ($kid = waitpid(-1, WNOHANG)) > 0 ) {
>         last;
>     }
> }
> # Cleanup and exit
> 
> 
> Regards,
> Carlyle.
> 
> Roland Giersig <rgi...@cp...> wrote on 06.02.2008 14:47:49:
> 
>> Can you post the relevant parts of the script?
>>
>> PTY-handling is hard, that's why IO::Tty is doing it in C. And you have
>> no way of installing IO::Tty locally? If you worry about distribution,
>> have a look at PAR, the Perl Archiver, on CPAN which lets you package
>> required modules, even binary ones, with your script.
>>
>> Servus, Roland
>>
>> Carlyle Sutphen wrote:
>>> Hello,
>>>
>>> I am a system administrator in a large corporation which
>>> has not included Expect.pm and its siblings IO::Tty and IO::Stty
>>> in the packaging.
>>>
>>> I have written a perl script which creates a terminal for a child
>>> process which uses the terminal rather than standard IO;
>>> much as expect does but very simply and of very limited
>>> scope.
>>>
>>> This script works fine on AIX but not on SunOS or Linux.
>>>
>>> I need to know how to get the name of the slave side after
>>> opening the control side (/dev/ptc on AIX and /dev/ptmx on
>>> the others). On AIX ttyname does this for me but it returns
>>> "Inappropriate ioctl for device" elsewhere.
>>>
>>> I don't mean to take up time and space on this list but I have been
>>> looking unsuccessfully for a suitable mailing list more suited to
>>> my problem.
>>>
>>> Thank you for any pointers.
>>>
>>> Best regards,
>>> Carlyle
>>> --
>>>
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> 
> --
> 
> Informationen (einschließlich Pflichtangaben) zu einzelnen, innerhalb der EU tätigen Gesellschaften und Zweigniederlassungen des Konzerns Deutsche Bank finden Sie unter http://www.db.com/de/content/pflichtangaben.htm. Diese E-Mail enthält vertrauliche und/ oder rechtlich geschützte Informationen. Wenn Sie nicht der richtige Adressat sind oder diese E-Mail irrtümlich erhalten haben, informieren Sie bitte sofort den Absender und vernichten Sie diese E-Mail. Das unerlaubte Kopieren sowie die unbefugte Weitergabe dieser E-Mail ist nicht gestattet.
> 
> Please refer to http://www.db.com/en/content/eu_disclosures.htm for information (including mandatory corporate particulars) on selected Deutsche Bank branches and group companies registered or incorporated in the European Union. This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and delete this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.
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