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Path: utzoo!attcan!uunet!mcvax!inria!gouldfr!cetia!chris
From: chris@cetia.UUCP (Chris Bertin)
Newsgroups: comp.unix.questions,comp.bugs.sys5
Subject: Re: SVR3 passwd changes mode of passwd file
Summary: there is MUCH worse in SYSV meddling with files!!!
Message-ID: <131@cetia.UUCP>
Date: 26 Sep 88 12:14:03 GMT
References: <3394@dunkshot.mips.COM> <7@marvin.UUCP> <3699@dunkshot.mips.COM>
Organization: Cetia, Toulon, France
Lines: 21


To change the mode of a file without being requested to is one thing, but
SYSV does much better when it comes to the 'utmp' handling. For fun, do

$ cp /etc/passwd /tmp
$ ls -l /tmp/passwd
$ who /tmp/passwd
$ ls -l /tmp/passwd

If the utmp code finds that the file you are doing 'who' on is not in 'utmp'
format, it ZEROES the file!!! Thank you AT&T.
The code is in libc/gen/getut.c. The wonderful comment says:
/* Make sure file is a multiple of 'utmp' entries long */
and if the file is not a multiple, it does an 'unlink' and a 'creat'...

Chris
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