[PATCH] gensignkey: ensure host keys are flushed to disk

[Matt Johnston]

On Tue, Oct 28, 2014 at 02:11:26PM +0100, Peter Korsgaard wrote:
> 
> Otherwise we can end up with an empty host key, breaking logins.
> 
> E.G.:
> 
> Run dropbear -R and pull power before the host key is writting to disk.
> After reboot we have:

Hi Peter,

Thanks for the patch, I've applied it with small changes.
https://secure.ucc.asn.au/hg/dropbear/rev/fd2e8bbb0333

Emmanuel - thanks for the review. Dropbear already has
exit-on-failure m_strdup(), I'm using that. I'll avoid
O_DIRECTORY since it's fairly harmless to leave out and is a
portability hassle. I've made it open with O_RDWR though can't
actually see in the opengroup.org posix docs where that is
required for fsync?

Cheers,
Matt