[FFmpeg-devel] [PATCH] Make av_get_random_seed not block when waiting for more entropy

[Måns Rullgård]

Martin Storsj? <martin at martin.st> writes:

> On Tue, 29 Jun 2010, Martin Storsj? wrote:
>
>> On Tue, 29 Jun 2010, M?ns Rullg?rd wrote:
>> 
>> > Martin Storsj? <martin at martin.st> writes:
>> > 
>> > > On Tue, 29 Jun 2010, M?ns Rullg?rd wrote:
>> > >
>> > >> This will still block if urandom isn't available.  How about this?
>> > >
>> > >> From cb60e983c550c2bdffc5fc07075336fb7c465fe9 Mon Sep 17 00:00:00 2001
>> > >> From: Mans Rullgard <mans at mansr.com>
>> > >> Date: Tue, 29 Jun 2010 14:22:51 +0100
>> > >> Subject: [PATCH] Make av_get_random_seed() non-blocking
>> > >> 
>> > >> Attempt to read from /dev/urandom and /dev/random with O_NONBLOCK set.
>> > >> If neither succeeds, proceed with fallbacks.
>> > >
>> > > In general, this looks like an even better alternative. Neither fcntl, 
>> > > F_SETFL, F_GETFL nor O_NONBLOCK are available on windows, though, so they 
>> > > need to be hidden within some kind of ifdef.
>> > 
>> > Cygwin should have them, mingw might not.
>> > 
>> > Do /dev/[u]random exist on cygwin/mingw?
>> 
>> Don't know about cygwin, but mingw won't have them at least, since it's 
>> almost plain win32.
>
> Would the cleanest fix be to check for fcntl and/or O_NONBLOCK in 
> configure, and just keep the nonblock setting line within ifdef? That 
> ought to work correctly on both cygwin and mingw.

Yes, that's what I was planning to do.

-- 
M?ns Rullg?rd
mans at mansr.com