Bug: tdb read-only open and truncate

[Jeremy Allison]

On Wed, Oct 03, 2001 at 08:16:40PM +0200, Elrond wrote:
> 
> Hi,
> 
> We got this report on tng-users and I'm forwarding it here
> with the author's permission.
> 
> It clearly describes a bug in tdb.
> 
> I suppose, you're also interested in fixing this.
> 
> 
>     Elrond
> 
> 
> p.s.: Our tdb is in sync with tdb in head, so anything said
>       here applies to your tdb (including line numbers).
> 
> 
> ----- Forwarded message from Phoenix <phoenix at comms.engg.susx.ac.uk> -----
> 
> From: Phoenix <phoenix at comms.engg.susx.ac.uk>
> To: <tng-users at samba-tng.org>
> Subject: tdb read-only open and truncate
> 
> 
> there is an error in tdb.c line ~1400 where you try to truncate the tdb
> file while it is opened read-only. this is on current cvs source.
> because the truncate fails and the tdb open calls fails along with it, I
> suppose it blocks access to the dbs (I'm not aware about the structure of
> the code, thus I might me mistaken. for sure "smbstatus" does not like
> it).
> 
> I changed the code to ignore the "goto fail" and log the attempts to
> truncate a read-only tdb. with one user in-session and another just loged
> in I got around 25 attempts on the log and everything seems to work fine.
> smbstatus turned back to normal, giving me a list of the locked files.
> 
> not sure if this is an already known bug/error. I can reproduce it with
> extensive logs if necessary.

tdb_open should cause a failure if opened with O_RDONLY and CLEAR_IF_FIRST.

I don't think any code in HEAD or 2.2 do this, but I'll add a failure
check in tdb/tdb.c to make sure.

Thanks for the bug report,

Jeremy.