Re: [Xen-devel] [PATCH 5 of 9] xl: Add function to generate random uuid and use it

[Gianni Tedesco <gianni.tedesco@xxxxxxxxxx>]

On Tue, 2010-07-27 at 11:13 +0100, Ian Campbell wrote:
> +static void random_uuid(uint8_t *uuid)
> +{
> +    int i;
> +    for (i = 0; i < 16; i++)
> +        uuid[i] = rand();
> +}
> +

Nothing wrong with the patch but draws my attention to the fact that
this method seems far too likely to collide UUID's, for example in xl
invocations started during the same second. Why not use system entropy
pool? eg. scanf contents of /proc/sys/kernel/rand/uuid... I'm aware this
ought to be portable but PRNG can always be a fallback.

Gianni


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