dd -- bs>=2G, error writing to /dev/null - possible bug? (win7; coreutils 8.26)
Corinna Vinschen
corinna-cygwin@cygwin.com
Sun Mar 12 11:39:00 GMT 2017
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 https://cygwin.de/snapshots/
Please give 'em a try.
Thanks,
Corinna
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Maintainer cygwin AT cygwin DOT com
Red Hat
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