broadcast messages

[Jim Diamond]

On Tue, Jan  7, 2014 at 00:27 (+0100), Michael Traxler wrote:

> 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...

Perhaps they use /usr/libexec/gnome-pty-helper, as my xfce4-terminal uses?
(See below.)

I did expect all of them to use libutempter, but digging around I
found the gnome-pty-helper.  But maybe there are others yet.

Cheers.
				Jim

> ---------------------------------------

> 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


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Dr. Jim Diamond       "Convenio ergo sum"      |                        /"\
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