Date: Mon, 27 Sep 2010 06:25:42 +1000 (EST) From: Bruce Evans <brde@optusnet.com.au> To: "Kevin K. Han" <ikevin.c11@revvo.org> Cc: freebsd-bugs@FreeBSD.org, freebsd-gnats-submit@FreeBSD.org Subject: Re: misc/150972: symbolic link bug Message-ID: <20100927060130.E5896@besplex.bde.org> In-Reply-To: <201009261824.o8QIORiF092345@www.freebsd.org> References: <201009261824.o8QIORiF092345@www.freebsd.org>
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On Sun, 26 Sep 2010, Kevin K. Han wrote: >> Description: > Create a directory on the root folder, for example ("/whatever"). > Switch to user's home directory ("cd /usr/home/username") ... from now onwards, work in this directory: > Create a symbolic link from inside a user's home ("ln -s /whatever .") > Execute this: ("chown -R username:username whatever") Apparently you are still running as root after creating /whatever. This chown -R has no effect even as root. (A plain chown would change /whatever and chown -h would change the symlink.) > Try to delete it using ("rm whatever")... it will say it is a directory. It is still not deleted! I don't see this. It would be a bad bug. rm is required to not follow symlinks. A broken version of rm might stat() the symlink and decide that it is a directory, and then rewrite its name to "whatever/" for maximal brokenness (other utilities do need to append a slash sometimes, and this is not easy to get right); then unlink("whatever/") would say it is a directory. > Then, try to delete using ("rm -r -f whatever/"), no errormessage, BUT It is still there! This is how symlinks work. "whatever/" is whatever the symlink points to. It is "/whatever" here. So this commands removes "/whatever" and leaves the symlink untouched. > Then, again, try the same thing ("rm whatever")... It is GONE, INCLUDING the original at "/whatever" !!! Consistent with a broken rm stat()ing the symlink. The previous command removed "/whatever", so "whatever" is a dangling symlink and stat()ing it wouldn't see it as a directory. Bruce
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