root@rdb1.UUCP (Robert Barrell) (06/05/90)
The SCO development system manuals mention the ability for ld or fixhdr to
set a stand-alone program address to create programs which would not run
directly from xenix. An example of this kind of program is /dos which, when
typed at the boot prompt, will boot the user to MSDOS if there is a proper DOS
partition on the hard drive. Unfortunately, the manuals don't make it very
clear as to how to create any such programs. I have tried, and when my
program's name is typed at the boot prompt, the machine just sits there.
What I'd like to do is very simple: I know a few people who wish to prevent
unauthorized people from booting their machines. Preventing a DOS boot-up is
easy, by just renaming /dos to something more cryptic (of course, this doesn't
account for floppy booting, but that's not the point here). I'd like to be able
to do something similar for /xenix but also have a few "dummy" programs to
replace the originals so that if "xenix" or "dos" are entered at the boot prompt
the user will get a message to the effect that access has been disallowed.
I tried something as simple as:
#include <stdio.h>
main()
{
printf("***** Sorry, access not allowed *****\n");
}
but that didn't work - even with the stand-alone address set to the same value
as that used by /dos. Is it possible for a C program to work stand-alone like
this, without having to resort to assembly (the last assembly I did was on Z80)?
Do I need to use different I/O routines (maybe something a little lower-level)?
Please respond by e-mail. If there is enough interest, I will post a
summary. Thanks.
--
Robert Barrell | ...!cbmvax!gvlv2!lock60!rdb1!root | Cody Computer Services
Milo's Meadow BBS | root@rdb1.canal.org | 55 East High Street
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