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From: meissner@osf.org (Michael Meissner)
Newsgroups: comp.lang.perl
Subject: Re: pwd in perl
Message-ID: <MEISSNER.90Aug10112018@osf.osf.org>
Date: 10 Aug 90 15:20:18 GMT
References: <1141@etnibsd.UUCP> <1990Aug9.225658.11586@NCoast.ORG>
Sender: news@OSF.ORG
Followup-To: comp.lang.perl
Organization: Open Software Foundation
Lines: 36
In-reply-to: allbery@NCoast.ORG's message of 9 Aug 90 22:56:58 GMT

In article <1990Aug9.225658.11586@NCoast.ORG> allbery@NCoast.ORG
(Brandon S. Allbery KB8JRR/KT) writes:

| As quoted from <1141@etnibsd.UUCP> by vsh@etnibsd.UUCP (Steve Harris):
| +---------------
| | 		while ($f = readdir(D)) {
| | 			next if $f eq '..';	# skip '..'
| | 			next if -l $f;		# skip links (but do lstat!)
| | 			next unless -d _;	# skip non-dirs
| | 			($d,$i) = stat(_);	# get dev, ino for dir
| | 			next unless ($d == $dc && $i == $ic);	# match?
| | 			last outerloop if ($f eq '.');	# root dir?
| | 			unshift(@path,$f);	# add dir to path
| | 			($dc,$ic) = ($dp,$ip);	# parent becomes next child
| | 			last;			# exit readdir loop
| | 		}
| +---------------
| 
| How about mount points?  I'm almost *never* in the root file system.
| You should also provide a way to get back where you were before you started;
| preferably, opendir() a string which is built incrementally ("../../.."...).
| 
| I just use chop($cwd = `pwd`); myself.  If it ever bothers me, I'll port Doug
| Gwyn's getcwd() to Perl.
| 
| ++Brandon

Another thing that I don't think has been mentioned, is that you might
be in a directory whose parent directory you have no access to.  In
this case reading ..'s files until you find . will not work.  This is
why pwd must be setuid root, so that it can do the appropriate checks.
--
Michael Meissner	email: meissner@osf.org		phone: 617-621-8861
Open Software Foundation, 11 Cambridge Center, Cambridge, MA, 02142

Do apple growers tell their kids money doesn't grow on bushes?