setuid (euid) after setuid (uid) on System 5

[Bob Lenk]

As numerous folks have said, the saved ID is overwritten when the euid
of the calling process is 0.  Also, in System V Release 2 (all versions
that I know of) a call to setuid(0) was never honored for a
non-superuser, even if the saved uid is 0.  This was not documented, and
I never understood or ascertained a good reason for this, and it was
apparently changed in release 3.  This could explain why one System V
port did not work the same as another.

		Bob Lenk
		hplabs!hpfcla!rml
		rml%hpfcla at hplabs.hp.com