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Re: creating backups in temporary directories
From: |
Davis Herring |
Subject: |
Re: creating backups in temporary directories |
Date: |
Tue, 11 Sep 2007 14:17:27 -0700 (PDT) |
User-agent: |
SquirrelMail/1.4.8-6.el3.2lanl |
> The code in backup-buffer-copy already does part of this;
> it calls copy-file in a way that uses O_EXCL.
Ah. That's good; I was trying to provide a self-contained concept rather
than a patch, if you take my meaning.
> If /tmp/foo~ already exists, rename it first to
> /tmp/backupforthebackup~
> rather than unlinking it; we have to get it out of the way and use
> O_EXCL
> even if we own it in case the directory's owner is the attacker.
>
> Why is this needed? When we're doing the copy, the actual source file
> also exists.
(By "this" you must mean the rename instead of the unlink; I trust that
the reason for having to do one or the other was understood.) I guess
it's not actually necessary. I was thinking it would be better to reduce
the amount of time when there was no backup; but at this point the user
wants the current contents of the actual file to _become_ the backup, so
the existing backup is completely expendable. (Of course, it gets more
complicated with numbered backups...)
Davis
--
This product is sold by volume, not by mass. If it appears too dense or
too sparse, it is because mass-energy conversion has occurred during
shipping.
- Re: creating backups in temporary directories, (continued)
- Re: creating backups in temporary directories, Stefan Monnier, 2007/09/07
- Re: creating backups in temporary directories, Richard Stallman, 2007/09/08
- Re: creating backups in temporary directories, Stefan Monnier, 2007/09/09
- Re: creating backups in temporary directories, David Kastrup, 2007/09/09
- Re: creating backups in temporary directories, Andreas Schwab, 2007/09/09
- Re: creating backups in temporary directories, David Kastrup, 2007/09/09
- Re: creating backups in temporary directories, Davis Herring, 2007/09/10
- Re: creating backups in temporary directories, David Kastrup, 2007/09/10
- Message not available
- Re: creating backups in temporary directories, Davis Herring, 2007/09/10
- Re: creating backups in temporary directories, Richard Stallman, 2007/09/11
- Re: creating backups in temporary directories,
Davis Herring <=
- Re: creating backups in temporary directories, Richard Stallman, 2007/09/09
- Re: creating backups in temporary directories, Stefan Monnier, 2007/09/09
- Re: creating backups in temporary directories, Davis Herring, 2007/09/07
- Re: creating backups in temporary directories, Chris Moore, 2007/09/08
- Re: creating backups in temporary directories, Richard Stallman, 2007/09/08
- Re: creating backups in temporary directories, Stefan Monnier, 2007/09/09
- Re: creating backups in temporary directories, David Kastrup, 2007/09/09
- Re: creating backups in temporary directories, Richard Stallman, 2007/09/09