Re: [Bug-tar] infinite loop in sparse_dump_region()

[Pavel Raiskup]

On Tuesday, December 19, 2017 9:30:49 AM CET Pavel Raiskup wrote:
> Hi, the proposed patch [1] can still be applied, and the reproducer below is
> still valid.  Please let me know I could fix something in the patch.
> 
> [1] https://www.mail-archive.com/address@hidden/msg04443.html

gently ping

Pavel

> On Sunday, March 16, 2014 10:55:38 PM CET Pavel Raiskup wrote:
> > Hello François,
> > 
> > On Thursday, March 13, 2014 14:43:55 François Ouellet wrote:
> > > When dumping a file which is being actively updated by an application
> > > (in our case it was an outlook pst file on our samba server), safe_read()
> > > can sometimes return 0.
> > > 
> > > When it happens, sparse_dump_region() goes into an infinite loop.
> > > 
> > > I don't know what the proper fix would be.  I just fixed it on our server
> > > with this:
> > 
> > thanks for clear report!  You can try the attached patch if you wanted (but 
> > it
> > has the same effects as yours one, just the message is little bit 
> > different).
> > Reproducer:
> > 
> >   $ truncate -s 10M file
> >   $ tar cSf archive file
> >   $ truncate -s 5M file
> >   $ tar df archive
> > 
> > Could we please apply at least something like the patch attached?
> > Looking at the code, I don't like duplications.  I was thinking
> > about safe_read/blocking_read wrapper with sth. like 'bool may_eof'
> > argument (and others) to make it possible to deal with errors at one
> > place (stopped once I realized that it will be somehow bigger code
> > change).  Would you be interested in such patch?
> > 
> > Pavel
> 
> 
>