> b) replace the shell script with a small C program, in case the shell on
>    Linux is "helping" in some way

For instance the SVR4 /bin/sh is known to change the EUID back to the RUID
whenever the EUID < 100.  There you have to but '#!/bin/sh -p' at the
top of any script you want to be suid, or run from a little program
that does setuid(geteuid()); execvp(argv[1], argv+1);

	David

-- 
David Laight: david@l8s.co.uk