Subject: Re: utmp file format change
To: James Graham <greywolf@starwolf.com>
From: Noriyuki Soda <soda@sra.co.jp>
List: tech-userlevel
Date: 08/23/2001 05:18:37
>>>>> On Wed, 22 Aug 2001 13:10:30 -0700 (PDT),
James Graham <greywolf@starwolf.com> said:
> So why don't we have utmp/wtmp writing facilities in libc and use those
> instead of writing directly?
That is not enough, because
- it doesn't provide binary compatibilty with old binaries.
- it cannot make utmp format changeable, because libc may be
statically linked.
What we have to do is:
- keep old utmp format
- provide API to access (extended) utmp information
- split implmentation of the API from libc,
by one of the following ways:
1. make a daemon to touch utmp information,
and access the daemon via socket.
2. make a shared object module to touch utmp
information, and access the module via dlopen(3).
3. only provide the API via shared object.
(do not permit to link it statically).
Unfortuntely, 2 and 3 won't work with platforms which
don't provide dynamic linking. So, probably 1 is the
only choice.
--
soda