Messages in this thread |  | | Date | Thu, 16 Nov 2000 19:51:48 +0100 (CET) | From | Jean-Marc Saffroy <> | Subject | Re: [BUG] Inconsistent behaviour of rmdir |
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On Thu, 16 Nov 2000, Alexander Viro wrote:
> > This is a point I don't understand here : do you mean that they are > > confused if they can rmdir "." but not if they can rmdir their cwd > > differently ? What's the difference ? > > rmdir() is _not_ "kill the directory identified by name and remove all > links to it". It's "remove a given link and .. in directory pointed > by it, then schedule directory for removal".
Now I see your point : by "." or "foo/." you mean the directory itself, while "foo" or "foo/" refer to the link to the directory, and they are obviously different objects... at least since hard links on directories were introduced. Fine.
> BTW, cwd is irrelevant - /tmp/foo/. would demonstrate the same behaviour.
We saw it, and found it shocking for the very same reasons...
> It becomes really obvious when you look at rename() - you act on links, > not on inodes. The only reason why we could try to overload that for > directories was that there is a special link - one from the parent. > However, _finding_ said link in race-free way is extremely nasty. > Especially for cases like /tmp/foo/. where /tmp/foo is a symlink to > /tmp/bar/baz. AFAIK Linux was the only system that tried to be smart > in that area. And that attempt was _not_ successful - there were rather > interesting races around the thing.
Ok, now I get it. Thanks for this much clearer explanation.
I guess that this was not a problem in 2.2 precisely because hard links on directories were forbidden, right ?
> Besides, we clearly violated > all relevant standards - rmdir() and rename() are required to fail > if the last component of name happens to "." or "..".
By standard, do you imply 'de facto' ? Or does any source clearly state this ?
-- Jean-Marc Saffroy - Research Engineer - Silicomp Research Institute mailto:jms@migrantprogrammer.com
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