Bridging console port to a telnet session
Mike Meyer
mwm-keyword-freebsdhackers2.e313df at mired.org
Wed Jan 17 18:47:14 UTC 2007
In <ecd0bee40701171024p7c5b4944of45b4c407ed3c5f4 at mail.gmail.com>, Kailas Ramasamy <kailasr at gmail.com> typed:
> Hi Mike,
> I read through fork() and exec() man pages but I couldn't find anything
> related to
> this. Basically, I want to launch a telnet session from a process and pass
> in
> /dev/console as stdin and stdout.
Well, you don't really need fork(), though fork() follows exec() so
often than some OS's combine them into a single call. And I just
noticed that if you do "man exec", you get the shell's page - you want
exec(3), to get the C calls.
Anyway, the sequence is:
Use open() to get an fd pointing at /dev/console.
Use dup2() to copy that fd to stdin and stdout (and probably stderr).
Use an exec() function to launch telnet.
<mike
> Thanks
> Kailas
>
> On 1/16/07, Mike Meyer <mwm at mired.org> wrote:
> >
> > In <ecd0bee40701161732v26112f24o2d8323c2777d2f7 at mail.gmail.com>, Kailas
> > Ramasamy <kailasr at gmail.com> typed:
> > > Hi Mike,
> > > Yes, that what I am planing but I want to do this dynamically. Do you
> > know
> > > how to launch a
> > > telnet session from a process?. How do I pass stdin and stdout to the
> > telnet
> > > from a process?.
> >
> > See the fork() and exec() man pages.
> >
> > <mike
> >
> >
> > > On 1/16/07, Mike Meyer <mwm at mired.org> wrote:
> > > >
> > > > In <ecd0bee40701161503k385819ddgba5562e137630617 at mail.gmail.com>,
> > Kailas
> > > > Ramasamy <kailasr at gmail.com> typed:
> > > > > Hi,
> > > > > Within a FreeBSD system, I want to telnet to another system and
> > bridge
> > > > that
> > > > > session to the
> > > > > console port so that when an user connects to the system via console
> > > > port,
> > > > > it is automatically
> > > > > redirected to other system for I have already established a telnet
> > > > session.
> > > >
> > > > What's wrong with simply leaving a telnet session running on the
> > > > console, maybe with some support to relaunch it should it ever exit?
> > > >
> > > > <mike
> > > > --
> > > > Mike Meyer <mwm at mired.org>
> > > > http://www.mired.org/consulting.html
> > > > Independent Network/Unix/Perforce consultant, email for more
> > information.
> > > >
> > > _______________________________________________
> > > freebsd-hackers at freebsd.org mailing list
> > > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
> > > To unsubscribe, send any mail to "
> > freebsd-hackers-unsubscribe at freebsd.org"
> > >
> >
> > --
> > Mike Meyer <mwm at mired.org>
> > http://www.mired.org/consulting.html
> > Independent Network/Unix/Perforce consultant, email for more information.
> >
> Hi Mike,<br>I read through fork() and exec() man pages but I couldn't find anything related to<br>this. Basically, I want to launch a telnet session from a process and pass in <br>/dev/console as stdin and stdout. <br>
> <br>Thanks<br>Kailas<br><br><div><span class="gmail_quote">On 1/16/07, <b class="gmail_sendername">Mike Meyer</b> <<a href="mailto:mwm at mired.org">mwm at mired.org</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
> In <<a href="mailto:ecd0bee40701161732v26112f24o2d8323c2777d2f7 at mail.gmail.com">ecd0bee40701161732v26112f24o2d8323c2777d2f7 at mail.gmail.com</a>>, Kailas Ramasamy <<a href="mailto:kailasr at gmail.com">kailasr at gmail.com
> </a>> typed:<br>> Hi Mike,<br>> Yes, that what I am planing but I want to do this dynamically. Do you know<br>> how to launch a<br>> telnet session from a process?. How do I pass stdin and stdout to the telnet
> <br>> from a process?.<br><br>See the fork() and exec() man pages.<br><br> <mike<br><br><br>> On 1/16/07, Mike Meyer <<a href="mailto:mwm at mired.org">mwm at mired.org</a>> wrote:<br>> ><br>> > In <
> <a href="mailto:ecd0bee40701161503k385819ddgba5562e137630617 at mail.gmail.com">ecd0bee40701161503k385819ddgba5562e137630617 at mail.gmail.com</a>>, Kailas<br>> > Ramasamy <<a href="mailto:kailasr at gmail.com">kailasr at gmail.com
> </a>> typed:<br>> > > Hi,<br>> > > Within a FreeBSD system, I want to telnet to another system and bridge<br>> > that<br>> > > session to the<br>> > > console port so that when an user connects to the system via console
> <br>> > port,<br>> > > it is automatically<br>> > > redirected to other system for I have already established a telnet<br>> > session.<br>> ><br>> > What's wrong with simply leaving a telnet session running on the
> <br>> > console, maybe with some support to relaunch it should it ever exit?<br>> ><br>> > <mike<br>> > --<br>> > Mike Meyer <<a href="mailto:mwm at mired.org">mwm at mired.org</a>>
> <br>> > <a href="http://www.mired.org/consulting.html">http://www.mired.org/consulting.html</a><br>> > Independent Network/Unix/Perforce consultant, email for more information.<br>> ><br>> _______________________________________________
> <br>> <a href="mailto:freebsd-hackers at freebsd.org">freebsd-hackers at freebsd.org</a> mailing list<br>> <a href="http://lists.freebsd.org/mailman/listinfo/freebsd-hackers">http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
> </a><br>> To unsubscribe, send any mail to "<a href="mailto:freebsd-hackers-unsubscribe at freebsd.org">freebsd-hackers-unsubscribe at freebsd.org</a>"<br>><br><br>--<br>Mike Meyer <<a href="mailto:mwm at mired.org">
> mwm at mired.org</a>> <a href="http://www.mired.org/consulting.html">http://www.mired.org/consulting.html</a><br>Independent Network/Unix/Perforce consultant, email for more information.<br></blockquote></div>
> <br>
--
Mike Meyer <mwm at mired.org> http://www.mired.org/consulting.html
Independent Network/Unix/Perforce consultant, email for more information.
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