From: Matthias Urlichs <smurf@smurf.noris.de>
Date: Wed, 13 Jul 2005 20:07:24 GMT
Subject: Re: [RFC PATCH] cogito --- don't overwrite metadata files in place (breaks CoW use)
Message-ID: <20050713200724.GN9915@kiste.smurf.noris.de>
In-Reply-To: <20050713185339.GA9260@taniwha.stupidest.org>

Hi,

Chris Wedgwood:
> How about the following?
> 
Ummm...

> 	    local NLINK=`readlink "$DEST"`
> 
> 	    if [ ! -e "$NLINK" ] ; then

You lose if the link is relative and the symlink is not in the current
directory. You also lose on systems where the empty filename is
synonymous with the current directory.

You'd need to do something along the lines of

	if [ -n "$NLINK" ] ; then
		case "$NLINK" in
		/*) ;;
		*) NLINK="$(dirname "$DEST")/$NLINK" ;;
		esac
	fi

first.

> 		# dangling link, just poke as-is
> 		echo "$1" > "$DEST"

You should remove "DEST first. Otherwise, under Linux, you'll magically
create the file the symlink points to, which may not be what you want to
do.

-- 
Matthias Urlichs   |   {M:U} IT Design @ m-u-it.de   |  smurf@smurf.noris.de
Disclaimer: The quote was selected randomly. Really. | http://smurf.noris.de
 - -
Custom does often reason overrule And only serves for reason to the fool.
					-- John Wilmot, Earl of Rochester