From: Eric Backus <ericb AT lsid DOT hp DOT com>
Subject: getuid vs. stat
To: djgpp AT sun DOT soe DOT clarkson DOT edu (djgpp)
Date: Tue, 7 Jul 92 9:18:53 PDT
Mailer: Elm [revision: 66.25]

I notice that getuid() and getgid() return something like 42 (or was
it 47?).  Since there aren't really different users (or groups) on a
PC, it would seem that the value returned doesn't matter.

However, if you stat() a file, it says that the file uid and gid are
zero.  Thus, a program that calls getuid() and stat() to see if it
owns a file will decide that it doesn't own the file and isn't allowed
to modify it.  This is of course not true.

It seems to me that stat() and getuid() should be consistant about
user ids.  Either both should use zero (so that all files are owned by
root, and all programs think they are run by root), or they should
both return the same non-zero value.  The second way is probably
slightly better but might be slightly harder to do.  The same argument
applies to group ids.

I ran into this when trying to compile the FSF fileutils.  One example
of the effects of the current setup is that the rm program doesn't
think it has write permission on any file, so it will prompt before
removing any file.
--
				Eric Backus
				ericb%hplsla AT hplabs DOT hp DOT com
				(206) 335-2495