Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!columbia!rutgers!princeton!allegra!alice!ark
From: ark@alice.UUCP
Newsgroups: comp.unix.questions
Subject: Re: access(2) question
Message-ID: <7000@alice.UUCP>
Date: Wed, 17-Jun-87 20:45:13 EDT
Article-I.D.: alice.7000
Posted: Wed Jun 17 20:45:13 1987
Date-Received: Sun, 21-Jun-87 11:33:40 EDT
References: <530@applix.UUCP>
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 10
Keywords: access permissions

In article <530@applix.UUCP>, mark@applix.UUCP writes:
> Does anybody know why access checks file accessibility using the real [ug]id
> in place of the effective [ug]id? It seems to me that access should agree
> with open(2) as far as whether a program has write or read access to a file.
> Inside a set-uid program that assumption obviously doesn't work while
> uid != euid.

The whole purpose of access(2) is to allow a set-uid program
to determine whether the real user can access a file.  It's easy
to see if the effective user can do it -- just try it and see.