Hi Leo,
Leo Famulari <[email protected]> skribis:
> On Fri, Jun 28, 2019 at 01:24:01PM -0400, Leo Famulari wrote:
>> So, I suggest we add a 1 second timeout to this read.
>>
>> I can work on that next week.
>
> I did try working on this, after reading the code in (guix scripts
> offload (call-with-timeout)).
The ‘start’ method of the ‘urandom-seed’ Shepherd service runs in PID 1,
so we certainly don’t want to fiddle with SIGALRM in that context, which
is what ‘call-with-timeout’ does.
Instead, I think we should use ‘select’ with a timeout:
(call-with-input-file "/dev/hwrng"
(lambda (port)
(match (select (list port) '() '() 3)
…)))
I think we can then use ‘get-bytevector-n!’, assuming it doesn’t block
if less than COUNT bytes are available (I’m not sure this is the case.)
HTH!
Ludo’.
