Xref: utzoo comp.unix.programmer:944 alt.sources.d:1410
Path: utzoo!utgpu!cs.utexas.edu!usc!jarthur!uunet!mcsun!hp4nl!star.cs.vu.nl!maart
From: maart@cs.vu.nl (Maarten Litmaath)
Newsgroups: comp.unix.programmer,alt.sources.d
Subject: Re: -x implementations
Message-ID: <8896@star.cs.vu.nl>
Date: 30 Jan 91 19:36:38 GMT
References: <1943:Jan2619:34:3591@kramden.acf.nyu.edu> <2856@charon.cwi.nl> <8869@star.cs.vu.nl> <1991Jan29.153242.12335@convex.com>
Sender: news@cs.vu.nl
Reply-To: maart@cs.vu.nl (Maarten Litmaath)
Organization: VU Dept. of Computer Science, Amsterdam, The Netherlands
Lines: 34

In article <1991Jan29.153242.12335@convex.com>,
	tchrist@convex.COM (Tom Christiansen) writes:
)From the keyboard of maart@cs.vu.nl (Maarten Litmaath):
):How does Perl implement `-x', Tom?
)
)It does its own stat, and then does the bit compares itself to 
)determine accessibility; it does not use access(2).

Good!

)Note that both -x and -X exist for checking effective and real IDs
)respectively; likewise -r/-R, -w/-W, and -o/-O.  Does this solve
)your problem?

I guess so.

)Could you show me some, um, test cases where /bin/test
)fails so I can see what perl does under the same circumstances?

As root:

	$ test -x /etc/passwd && echo 'Huh?  /etc/passwd is executable?'

If your effective uid is that of user `foo', whereas your real uid is
that of user `bar':

	$ ls -l mailbox
	-rw-------  1 foo          1079 Jan 30 19:26 mailbox
	$ test -r mailbox || echo 'Huh?  Is mailbox unreadable for me?'

Access(2), a sick system call.  (I _know_ it uses the real uid on
purpose.)
--
Temporary files like /tmp/sh$$ are an abomination.