NetNews Usenet Archive 1992 #26/NN_1992_26.iso/spool/comp/os/linux/15725

Internet Message Format | 1992-11-05 | 2.0 KB

Path: sparky!uunet!pipex!warwick!uknet!mcsun!sun4nl!cwi.nl!sander
From: [e-mail] (Sander Plomp)
Newsgroups: comp.os.linux
Subject: Re: Strange minix fs problem: duplicate core files in directory!
Message-ID: <[e-mail]>
Date: 5 Nov 92 10:01:23 GMT
References: <[e-mail]> <[e-mail]>
Sender: [e-mail]
Lines: 30

[e-mail] (Linus Torvalds) writes:

>You can create several files with the same name in the same directory
>just by stressing the system very hard and trying to create files with
>the same name.  It's a harmless way to have some fun on your system: the
>files are distinct but have the same name so you could possibly confuse
>some programs with it.  You can delete them one-by one, or simply rename
>them: doing a rename on the name will rename the file that is first in
>the directory, while the other will still have the old name.  It's fun
>to mess with the minds of innocent programs by doing these kinds of
>stunts - has anybody tried tarring such a directory?

>Note that it isn't exactly easy to create these kinds of duplicate
>names: you really have to swap pretty badly.  I guess I should document
>it and add it as a "feature" to linux: it's harmless enough that I
>probably won't try very hard to get it corrected.

Are you sure it is harmless? I though some programs use "lock files" to
ensure exclusive access to something. File creation is supposed to be
atomic, so the idea is that only one process will be able to succesfully
create the lock file. This is not true of linux I gather, are there other
unix variants for which it is also not true?

Of course file creation is a very stupid mechanism to implement locking,
but as far as I know there no other portable mechanism, so it is often used.

I know the chances of things going wrong will be small but I would not
call it harmless. I suggest "mostly harmless".
--
Sander Plomp                                    Internet: [e-mail]