On Thu, Jul 17, 2014, Theodore Ts'o wrote:

The getrandom(2) system call is a superset of getentropy(2).  When we
add the support for this into glibc, it won't be terribly difficult
nor annoying to drop the following in alongside the standard support
needed for any new system call:

int getentropy(void *buf, size_t buflen)
{
	int	ret;

	ret = getentropy(buf, buflen, 0);
	return (ret > 0) ? 0 : ret;
}

I'm sure you meant to use getrandom() there ;)

Since for LibreSSL we'd want a getentropy() that cannot fail the
getrandom() call should use GRND_BLOCK flag.  Actually it makes sense
(to me) to make blocking the default behaviour and have a
BRND_NONBLOCK flag.  Much in the same way as you need to specify
O_NONBLOCK if you want non-blocking behaviour for files.