broadcast messages

[Michael Traxler]

Hello Jim,

thanks for the explanation.
Yes, this method seems to be the correct way: To use an external program to do
the privileged update of /var/run/utmp. The setgid bit for urxvt seems to
"drastic" just for this small job. What happens if one of the many other tasks also
need a setgid bit, but for a different group?

On my system xterm uses libutempter
  % ldd /usr/bin/xterm | grep utemp
  libutempter.so.0 => /usr/lib64/libutempter.so.0 (0x00007f5d99cf8000)

but the others terminal programs don't use this but still are able to write to
/var/run/utemp by some way...

Michael

---------------------------------------

On Mon, 6 Jan 2014, Jim Diamond wrote:

> Date: Mon, 6 Jan 2014 11:05:48 -0400
> From: Jim Diamond <Jim.Diamond at acadiau.ca>
> To: Michael Traxler <M.Traxler at gsi.de>
> Cc: rxvt-unicode at lists.schmorp.de
> Subject: Re: broadcast messages
> 
> On Sun, Jan  5, 2014 at 23:37 (+0100), Michael Traxler wrote:
>
>> Hello Marc,
>
>> thanks a lot for your fast help!
>
>> On SuSE13.1 chown root.utmp /usr/bin/urxvt; chmod g+s /usr/bin/urxvt
>> solves the problem.
>
>> But still I'm confused:
>> Why does urxvt needs the setgid utmp while xterm and the others don't need this
>> to enable the registration in utmp?
>
>>  % ls -l /usr/bin/(xterm|lxterminal|gnome-terminal|urxvt)
>> -rwxr-xr-x 1 root root   81888 22. Nov 13:18 /usr/bin/gnome-terminal
>> -rwxr-xr-x 1 root root   59552 28. Sep 12:34 /usr/bin/lxterminal
>> -rwxr-sr-x 1 root utmp 1307664  8. Nov 17:02 /usr/bin/urxvt
>> -rwxr-xr-x 1 root root  506832  2. Okt 13:53 /usr/bin/xterm
>
> Michael,
>
> I don't have gnome-terminal or lxterminal on my system, but xterm,
> rxvt and mrxvt are all linked with libutempter, which (apparently)
> uses the setgid program /usr/lib<64>/utempter to do the privileged
> update of /var/run/utmp.
>
> (As you may already know) you can check out your other terminals with
> a line like
> 	ldd /usr/bin/gnome-terminal | grep utemp
>
> I also have /usr/bin/xfce4-terminal which is not linked to
> libutempter, but it seems to use the setgid program
> /usr/libexec/gnome-pty-helper to do the update.
>
> Cheers.
>
> 				Jim
>