Re: [rdiff-backup-users] Write-once read-many problem

[Ben Escoto]

>>>>> dean gaudet <address@hidden>
>>>>> wrote the following on Wed, 20 Jul 2005 12:30:59 -0700 (PDT)

> On Wed, 20 Jul 2005, Sheldon Hearn wrote:
> 
> > If we're not root on the server during a restore operation, we try to 
> > change permissions to ensure readability?  Either we can read an object 
> > or we can't.  If we can't, it's _highly_ unlikely that we'll be able to 
> > change permissions on it anyway.
> 
> only root can read mode 0 files ... this code exists so that if you're 
> non-root you can backup and restore mode 0 files which you own... but it 
> is kind of unfortunate, isn't it?

Yes, exactly.  This code is conceptually messy and has been a source
of errors in the past, but I think it's working correctly in this
instance.

For instance, suppose you (or your pesky users) on computer A make
some directories then set the perms to 0.  Then you as root on
computer A back up those directories to a non-root account on computer
B.  For this to work when restoring the non-root account on computer B
will have to increase the permissions in order to read stuff and then
reset them as it leaves.

Before rdiff-backup would attempt to do this to the source partition
when backing up, but fortunately it doesn't do this any more.  (I
admit this was a bad idea--it led to someone losing their whole source
directory!)

> i'm tempted to change it so that a command line option is required
> to enable the mode futzing... by default i'd really prefer backup
> and restore sources be completely read-only.

Well I'd prefer that the default behavior stay the same.  It is
somewhat unfortunate, but by default the setup I mentioned above
should work.

Does it still mess with the permissions when run as root?  As root I
would hope it realizes it doesn't need to change anything.


-- 
Ben Escoto