Andrea <[log in to unmask]> writes:

> Il 15/08/2008 alle 10:57, Dr Andrew C Aitchison ha scritto:

>> Login processes have to register with utmp, but not all login
>> processes have permission to do this (essentially by writing to
>> /var/log/wtmp).  xterm is the program which springs to mind as
>> sometimes not have having permission to do this.
>
> Interesting. I don't know much about this topic, so any pointers are
> welcome.

I don't have access to SL5.1 but on 4.4 xterm has no set-u/g id bit:

bv@minos05:~> ls -l /usr/bin/xterm
-rwxr-xr-x  1 root root 258396 Nov 15  2007 /usr/bin/xterm*

On my Debian workstation:

bviren@lycastus:~> ls -l /usr/bin/xterm
-rwxr-sr-x 1 root utmp 318832 Mar 19 10:09 /usr/bin/xterm*
bviren@lycastus:~> ls -l /var/log/wtmp
-rw-rw-r-- 1 root utmp 109440 Aug 15 11:25 /var/log/wtmp

So the set-gid utmp lets xterm write to wtmp.  I can't conceive of why
TUV doesn't do this as well.

Cheers,
-Brett.