[FFmpeg-devel] [PATCH 1/2] avutil/random_seed: add av_random()

[Anton Khirnov]

Quoting James Almer (2023-07-04 22:08:40)
> On 7/4/2023 4:59 PM, Anton Khirnov wrote:
> >>
> >> Not if any of the functions above were called but failed to fill the buffer.
> >>
> >> I could add return AVERROR(ENOSYS) to the HAVE_UNISTD_H block, and
> >> return AVERROR_INVALIDDATA outside.
> > 
> > AVERROR_INVALIDDATA is defined as 'Invalid data found when processing
> > input'.
> > This function does not process any input, so IMO that code never makes
> > sense for it.
> > 
> > I'd say make it ENOSYS, AVERROR_UNKNOWN, or keep around one of
> > individual method errors.
> 
> For the cases read() is used for /dev/random/, i can return 
> AVERROR(errno), given the doxy states read() returns -1 on error and 
> sets errno to some value. Although if it succeeds and returns a value 
> smaller than len i would need to return AVERROR_UNKNOWN like you suggested.

I wonder if we should be trying /dev/random at all. I cannot think of
any remotely sane configuration where /dev/urandom fails, but
/dev/random works. So it only makes sense to use /dev/urandom.

-- 
Anton Khirnov