On Tue, 27 Dec 2016 11:32:32 +0100
Laslo Hunhold <dev_AT_frign.de> wrote:
> On Sat, 26 Mar 2016 13:50:47 +0100
> Mattias Andrée <maandree_AT_kth.se> wrote:
>
> Hey Mattias,
>
> > +static int
> > +random_byte_file(void)
> > +{
> > + unsigned char r;
> > + ssize_t n = read(source, &r, 1);
> > + if (n < 0)
> > + eprintf("read %s:", sflag);
> > + if (!n)
> > + eprintf("read %s: end of file
> > reached\n");
> > + return r;
> > +}
> > +
> > +static int
> > +random_byte_libc(void)
> > +{
> > + double r;
> > + r = rand();
> > + r /= (double)RAND_MAX + 1;
> > + r *= 256;
> > + return (int)r;
> > +}
>
> is there a good reason for the existence of shuf(1)?
> Also, we may want to think about using more solid
> interfaces for randomness (like arc4random()) and remove
> the "file-source" altogether.
>
> Cheers
>
> Laslo
>
Hi Laslo!
No, we don't really need shuf(1) in sbase, but I think we
should have a suckless implementation available, it can be
a useful utility. I have a few more utilities I fund useful
but I haven't bothered to set up a repository yet. I tried
to start a discussion with Dimitris some time ago, but I
didn't get a response. I think it might be a good idea to
have sextra for portable utilities and uextra for unportable
utilities, if you have any other suggestions I would like
to hear them.
For sextra I have written base16(1), base32(1), base64(1),
prune(1) which recursively removes empty directories, rev(1)
and shuf(1). For uextra I have written fsize(1) which
print the size of any regular file or block device (other
do not print the size of block devices so it can be quite
burdensome to find out how large one is), printenvx(1) which
is like printenv(1) but for other processes, and shred(1),
and I'm working on rescue(1) which is similar to ddrescue(1).
I'm not sure that arc4random() is portable, but my
understanding is that each bit in the output of rand()
have the same entropy in modern libc implementations, and
that is all that is needed in my opinion. I don't know
whether it is a good to include reading random data from
files, so it should probably be removed.
Mattias Andrée
Received on Tue Dec 27 2016 - 13:43:45 CET