* dev_urandom() now calls py_getentropy(). Prepare the fallback to support
getentropy() failure and falls back on reading from /dev/urandom.
* Simplify dev_urandom(). pyurandom() is now responsible to call getentropy()
or getrandom(). Enhance also dev_urandom() and pyurandom() documentation.
* getrandom() is now preferred over getentropy(). The glibc 2.24 now implements
getentropy() on Linux using the getrandom() syscall. But getentropy()
doesn't support non-blocking mode. Since getrandom() is tried first, it's not
more needed to explicitly exclude getentropy() on Solaris. Replace:
"if defined(HAVE_GETENTROPY) && !defined(sun)"
with "if defined(HAVE_GETENTROPY)"
* Enhance py_getrandom() documentation. py_getentropy() now supports ENOSYS,
EPERM & EINTR
Issue #27776: The os.urandom() function does now block on Linux 3.17 and newer
until the system urandom entropy pool is initialized to increase the security.
This change is part of the PEP 524.
Modify py_getrandom() to not call PyErr_CheckSignals() if raise is zero.
_PyRandom_Init() is called very early in the Python initialization, so it's
safer to not call PyErr_CheckSignals().
* Add pyurandom() helper function to factorize the code
* don't call Py_FatalError() in helper functions, but only in _PyRandom_Init()
if pyurandom() failed, to uniformize the code
Issue #27278: Fix os.urandom() implementation using getrandom() on Linux.
Truncate size to INT_MAX and loop until we collected enough random bytes,
instead of casting a directly Py_ssize_t to int.
