Re: [PATCH] Improve mutt's random data generator.

On Thu, Apr 23, 2026 at 09:40:13PM -0400, Kurt Hackenberg wrote:
>On Fri, Apr 24, 2026 at 09:28 +0800, Kevin J. McCarthy wrote:
>
>>>> if (res < length_requested)
>>>> {
>>>>   length_requested -= res;
>>>>   random_bytes += res;
>>>> }
>>>
>>>I hope that code is not executed if the return value is -1.
>>
>>Yup.  That's exactly what I meant by making the code clearer.  If 
>>res is type size_t, then it can't be -1 in that comparison.
>
>I'm asking: is that code executed when the return value is -1? If not, 
>then we don't have to care whether it works in that error case.

Ah, sorry.  Yes, the code is executed.  The whole snippet is:

   if ((res == (size_t) -1) || (res < length_requested))
   {
     if (res < length_requested)
     {
       length_requested -= res;
       random_bytes += res;
     }
     prng_random_bytes(random_bytes, length_requested);
   }

So, when res was size_t, I explicitly checked for the -1 retval via a 
cast.  For the inner check "if (res < length_requested)", because it's a 
size_t, the res will be the maximum positive value, and can't be < 
length_requested.  So that inner check will only execute when the number 
of bytes returned was truncated.

IMO, I think the sacrifice of the (size_t)-1 cast checks make the rest 
of the code clearer...

-- 
Kevin J. McCarthy
GPG Fingerprint: 8975 A9B3 3AA3 7910 385C  5308 ADEF 7684 8031 6BDA

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