problem retaining username

[Andrew Solomon]

I apologise if this question is already answered and I just don't
understand it:

TASK: I want to write a script, called by any user,
which creates a file owned by root in a directory owned by root.

e.g user types

  sudo timestamp.sh

and timestamp does

  touch /root/<loginname>.timestamp

PROBLEM: I'm having two problems.

1) the script timestamp.sh is owned by root with permissions 700
but with the following line in my sudoers:

  andrews machname=/bin/timestamp.sh !set_logname

I get the message

  Sorry, user andrews is not allowed to execute '/bin/timestamp.sh' 
  as root on machname.it.uts.edu.au.

What am I doing wrong?

2) If I *were* able to execute /bin/timestamp.sh 
as root but with $USER unchanged by sudo, I would worry that 
the person executing 
 
  sudo /bin/timestamp.sh

had tampered with their $USER variable. Is there any way of ensuring
this had not been done?


best wishes,

Andrew
-- 
Faculty of IT, UTS                     http://www-staff.it.uts.edu.au/~andrews/
Broadway, NSW 2007, Australia          phone:+61.2.9514 7938
CRICOS Provider 00099F                 room:UTS blg 10/4.433