dd -- bs>=2G, error writing to /dev/null - possible bug? (win7; coreutils 8.26)

Corinna Vinschen corinna-cygwin@cygwin.com
Sun Mar 12 17:01:00 GMT 2017


On Mar 12 15:49, Marco Atzeri wrote:
> On 12/03/2017 12:39, Corinna Vinschen wrote:
> > On Mar 12 00:33, Josef Frank wrote:
> > > 
> > > Dear all,
> > > 
> > > 
> > > dd utility has problems to write to /dev/null with bs>=2^31,
> > > while bs<2^31 is ok.
> > > 
> > > Increasing bs further to 2^33 leads to extended error message
> > > 
> > > For description see below
> > 
> > Thanks for the testcase.  It's a combination of two bugs:
> > 
> > - At a crucial point in write(2), Cygwin used an int variable where
> >   it should have used a ssize_t variable.  This fouled up the return
> >   value for lengths >= 2^31.
> > 
> > - When writing to the Windows NUL device, NtWriteFile only returns the
> >   lower 32 bits od the number of bytes written.  This fouls up the
> >   return value of write(2) for lengths >= 2^32.
> > 
> > I fixed the first problem and created a workaround for the second.
> > 
> > I uploaded new developer snapshots to XXXXXXXXXXXXXXXXXXXXXXXXXXXX
> > Please give 'em a try.
> 
> May be
> https://cygwin.com/snapshots/

Oops, right :)


Thanks,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat
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