gnu: python@3: Update to 3.6.3.

* gnu/packages/patches/python-3.5-fix-tests.patch: Rename to ...
* gnu/packages/patches/python-3-fix-tests.patch: ... this. Adjust and disable
more tests.
* gnu/packages/patches/python-3.5-getentropy-on-old-kernels.patch: Delete file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/python.scm (python-2.7)[argument]: Patch '/bin/sh' in one more file.
(python-3.5): Rename to ...
(python-3.6): ... this. Update to 3.6.3.
[source](patches): Remove obsolete patch, adjust to patch rename.
(python-3): Use PYTHON-3.6.

3 files changed, 149 insertions, 789 deletions

diff --git a/gnu/packages/patches/python-3-fix-tests.patch b/gnu/packages/patches/python-3-fix-tests.patch
new file mode 100644
index 0000000000..ab713c54dd
--- /dev/null
+++ b/gnu/packages/patches/python-3-fix-tests.patch
@@ -0,0 +1,149 @@
+Additional test fixes which affect Python 3.5 (and presumably later) but not
+prior revisions of Python.
+
+--- Lib/test/test_pathlib.py     2014-03-01 03:02:36.088311000 +0100
++++ Lib/test/test_pathlib.py     2014-03-01 04:56:37.768311000 +0100
+@@ -2132,8 +2132,7 @@
+         self.assertEqual(given, expect)
+         self.assertEqual(set(p.rglob("FILEd*")), set())
+ 
+-    @unittest.skipUnless(hasattr(pwd, 'getpwall'),
+-                         'pwd module does not expose getpwall()')
++    @unittest.skipIf(True, "Guix builder home is '/' which causes trouble for these tests")
+     def test_expanduser(self):
+         P = self.cls
+         support.import_module('pwd')
+--- Lib/test/test_tarfile.py        2016-02-24 19:22:52.597208055 +0000
++++ Lib/test/test_tarfile.py     2016-02-24 20:50:48.941950135 +0000
+@@ -2305,11 +2305,14 @@
+     try:
+         import pwd, grp
+     except ImportError:
+         return False
+-    if pwd.getpwuid(0)[0] != 'root':
+-        return False
+-    if grp.getgrgid(0)[0] != 'root':
++    try:
++        if pwd.getpwuid(0)[0] != 'root':
++            return False
++        if grp.getgrgid(0)[0] != 'root':
++            return False
++    except KeyError:
+         return False
+     return True
+
+
+--- Lib/test/test_asyncio/test_base_events.py
++++ Lib/test/test_asyncio/test_base_events.py
+@@ -1216,6 +1216,8 @@
+         self._test_create_connection_ip_addr(m_socket, False)
+
+     @patch_socket
++    @unittest.skipUnless(support.is_resource_enabled('network'),
++                         'network is not enabled')
+     def test_create_connection_service_name(self, m_socket):
+         m_socket.getaddrinfo = socket.getaddrinfo
+         sock = m_socket.socket.return_value
+
+--- Lib/test/test_pdb.py.org    2017-03-12 03:09:01.991856701 +0100
++++ Lib/test/test_pdb.py        2017-03-12 03:26:17.742572869 +0100
+
+For some reason, KeyboardInterrupts do not work in the build
+environment (lack of controlling TTY?). Just change the expected
+outcome. Unfortunately, this will make it fail for users running
+`python -m test test_pdb test_pdb` interactively.
+
+@@ -928,11 +928,11 @@
+     > <doctest test.test_pdb.test_pdb_issue_20766[0]>(6)test_function()
+     -> print('pdb %d: %s' % (i, sess._previous_sigint_handler))
+     (Pdb) continue
+-    pdb 1: <built-in function default_int_handler>
++    pdb 1: Handlers.SIG_IGN
+     > <doctest test.test_pdb.test_pdb_issue_20766[0]>(5)test_function()
+     -> sess.set_trace(sys._getframe())
+     (Pdb) continue
+-    pdb 2: <built-in function default_int_handler>
++    pdb 2: Handlers.SIG_IGN
+     """
+
+ class PdbTestCase(unittest.TestCase):
+--- Lib/test/test_socket.py
++++ Lib/test/test_socket.py
+@@ -802,6 +802,8 @@
+         if not fqhn in all_host_names:
+             self.fail("Error testing host resolution mechanisms. (fqdn: %s, all: %s)" % (fqhn, repr(all_host_names)))
+ 
++    @unittest.skipUnless(support.is_resource_enabled('network'),
++                         'network is not enabled')
+     def test_host_resolution(self):
+         for addr in [support.HOST, '10.0.0.1', '255.255.255.255']:
+             self.assertEqual(socket.gethostbyname(addr), addr)
+--- Lib/test/test_spwd.py
++++ Lib/test/test_spwd.py
+@@ -5,8 +5,7 @@
+ spwd = support.import_module('spwd')
+ 
+ 
+-@unittest.skipUnless(hasattr(os, 'geteuid') and os.geteuid() == 0,
+-                     'root privileges required')
++@unittest.skipUnless(os.path.exists("/etc/shadow"), 'spwd tests require /etc/shadow')
+ class TestSpwdRoot(unittest.TestCase):
+ 
+     def test_getspall(self):
+@@ -56,8 +55,7 @@
+             self.assertRaises(TypeError, spwd.getspnam, bytes_name)
+ 
+ 
+-@unittest.skipUnless(hasattr(os, 'geteuid') and os.geteuid() != 0,
+-                     'non-root user required')
++@unittest.skipUnless(os.path.exists("/etc/shadow"), 'spwd tests require /etc/shadow')
+ class TestSpwdNonRoot(unittest.TestCase):
+ 
+     def test_getspnam_exception(self):
+--- Lib/test/test_regrtest.py
++++ Lib/test/test_regrtest.py
+@@ -700,6 +700,7 @@
+         output = self.run_tests('--fromfile', filename)
+         self.check_executed_tests(output, tests)
+ 
++    @unittest.skipIf(True, 'Keyboard interrupts do not work in the Guix build environment.')
+     def test_interrupted(self):
+         code = TEST_INTERRUPTED
+         test = self.create_test('sigint', code=code)
+@@ -717,6 +718,7 @@
+                  % (self.TESTNAME_REGEX, len(tests)))
+         self.check_line(output, regex)
+ 
++    @unittest.skipIf(True, 'Keyboard interrupts do not work in the Guix build environment.')
+     def test_slow_interrupted(self):
+         # Issue #25373: test --slowest with an interrupted test
+         code = TEST_INTERRUPTED
+--- Lib/test/test_generators.py
++++ Lib/test/test_generators.py
+@@ -29,6 +29,7 @@
+         else:
+             return "FAILED"
+ 
++    @unittest.skipIf(True, 'Keyboard interrupts do not work in the Guix build environment')
+     def test_raise_and_yield_from(self):
+         gen = self.generator1()
+         gen.send(None)
+--- Lib/test/test_normalization.py
++++ Lib/test/test_normalization.py
+@@ -2,6 +2,7 @@
+ import unittest
+ 
+ from http.client import HTTPException
++from urllib.error import URLError
+ import sys
+ from unicodedata import normalize, unidata_version
+ 
+@@ -43,6 +44,8 @@
+         except PermissionError:
+             self.skipTest(f"Permission error when downloading {TESTDATAURL} "
+                           f"into the test data directory")
++        except URLError:
++            self.skipTest("DNS lookups are not enabled.")
+         except (OSError, HTTPException):
+             self.fail(f"Could not retrieve {TESTDATAURL}")
+ 
diff --git a/gnu/packages/patches/python-3.5-fix-tests.patch b/gnu/packages/patches/python-3.5-fix-tests.patch
deleted file mode 100644
index 9778b88dbd..0000000000
--- a/gnu/packages/patches/python-3.5-fix-tests.patch
+++ /dev/null
@@ -1,69 +0,0 @@
-Additional test fixes which affect Python 3.5 (and presumably later) but not
-prior revisions of Python.
-
---- Lib/test/test_pathlib.py     2014-03-01 03:02:36.088311000 +0100
-+++ Lib/test/test_pathlib.py     2014-03-01 04:56:37.768311000 +0100
-@@ -1986,8 +1986,9 @@
-         expect = set() if not support.fs_is_case_insensitive(BASE) else given
-         self.assertEqual(given, expect)
-         self.assertEqual(set(p.rglob("FILEd*")), set())
- 
-+    @unittest.skipIf(True, "Guix builder home is '/' which causes trouble for these tests")
-     def test_expanduser(self):
-         P = self.cls
-         support.import_module('pwd')
-         import pwd
---- Lib/test/test_tarfile.py        2016-02-24 19:22:52.597208055 +0000
-+++ Lib/test/test_tarfile.py     2016-02-24 20:50:48.941950135 +0000
-@@ -2305,11 +2305,14 @@
-     try:
-         import pwd, grp
-     except ImportError:
-         return False
--    if pwd.getpwuid(0)[0] != 'root':
--        return False
--    if grp.getgrgid(0)[0] != 'root':
-+    try:
-+        if pwd.getpwuid(0)[0] != 'root':
-+            return False
-+        if grp.getgrgid(0)[0] != 'root':
-+            return False
-+    except KeyError:
-         return False
-     return True
-
-
---- Lib/test/test_asyncio/test_base_events.py
-+++ Lib/test/test_asyncio/test_base_events.py
-@@ -1216,6 +1216,8 @@
-         self._test_create_connection_ip_addr(m_socket, False)
-
-     @patch_socket
-+    @unittest.skipUnless(support.is_resource_enabled('network'),
-+                         'network is not enabled')
-     def test_create_connection_service_name(self, m_socket):
-         m_socket.getaddrinfo = socket.getaddrinfo
-         sock = m_socket.socket.return_value
-
---- Lib/test/test_pdb.py.org    2017-03-12 03:09:01.991856701 +0100
-+++ Lib/test/test_pdb.py        2017-03-12 03:26:17.742572869 +0100
-
-For some reason, KeyboardInterrupts do not work in the build
-environment (lack of controlling TTY?). Just change the expected
-outcome. Unfortunately, this will make it fail for users running
-`python -m test test_pdb test_pdb` interactively.
-
-@@ -928,11 +928,11 @@
-     > <doctest test.test_pdb.test_pdb_issue_20766[0]>(6)test_function()
-     -> print('pdb %d: %s' % (i, sess._previous_sigint_handler))
-     (Pdb) continue
--    pdb 1: <built-in function default_int_handler>
-+    pdb 1: Handlers.SIG_IGN
-     > <doctest test.test_pdb.test_pdb_issue_20766[0]>(5)test_function()
-     -> sess.set_trace(sys._getframe())
-     (Pdb) continue
--    pdb 2: <built-in function default_int_handler>
-+    pdb 2: Handlers.SIG_IGN
-     """
-
- class PdbTestCase(unittest.TestCase):
diff --git a/gnu/packages/patches/python-3.5-getentropy-on-old-kernels.patch b/gnu/packages/patches/python-3.5-getentropy-on-old-kernels.patch
deleted file mode 100644
index 8a12b5b448..0000000000
--- a/gnu/packages/patches/python-3.5-getentropy-on-old-kernels.patch
+++ /dev/null
@@ -1,720 +0,0 @@
-This patch resolves a compatibility issue when compiled against glibc 2.25
-and run runder kernels < 3.17:
-
-https://bugzilla.redhat.com/show_bug.cgi?id=1410175
-
-Upstream bug URL: https://bugs.python.org/issue29157
-
-Patch copied from upstream source repository:
-
-https://hg.python.org/cpython/rev/8125d9a8152b
-
-# HG changeset patch
-# User Victor Stinner <victor.stinner@gmail.com>
-# Date 1483957133 -3600
-# Node ID 8125d9a8152b79e712cb09c7094b9129b9bcea86
-# Parent  337461574c90281630751b6095c4e1baf380cf7d
-Issue #29157: Prefer getrandom() over getentropy()
-
-Copy and then adapt Python/random.c from default branch. Difference between 3.5
-and default branches:
-
-* Python 3.5 only uses getrandom() in non-blocking mode: flags=GRND_NONBLOCK
-* If getrandom() fails with EAGAIN: py_getrandom() immediately fails and
-  remembers that getrandom() doesn't work.
-* Python 3.5 has no _PyOS_URandomNonblock() function: _PyOS_URandom()
-  works in non-blocking mode on Python 3.5
-
-diff --git a/Python/random.c b/Python/random.c
---- Python/random.c
-+++ Python/random.c
-@@ -1,6 +1,9 @@
- #include "Python.h"
- #ifdef MS_WINDOWS
- #  include <windows.h>
-+/* All sample MSDN wincrypt programs include the header below. It is at least
-+ * required with Min GW. */
-+#  include <wincrypt.h>
- #else
- #  include <fcntl.h>
- #  ifdef HAVE_SYS_STAT_H
-@@ -37,10 +40,9 @@ win32_urandom_init(int raise)
-     return 0;
- 
- error:
--    if (raise)
-+    if (raise) {
-         PyErr_SetFromWindowsErr(0);
--    else
--        Py_FatalError("Failed to initialize Windows random API (CryptoGen)");
-+    }
-     return -1;
- }
- 
-@@ -53,8 +55,9 @@ win32_urandom(unsigned char *buffer, Py_
- 
-     if (hCryptProv == 0)
-     {
--        if (win32_urandom_init(raise) == -1)
-+        if (win32_urandom_init(raise) == -1) {
-             return -1;
-+        }
-     }
- 
-     while (size > 0)
-@@ -63,11 +66,9 @@ win32_urandom(unsigned char *buffer, Py_
-         if (!CryptGenRandom(hCryptProv, (DWORD)chunk, buffer))
-         {
-             /* CryptGenRandom() failed */
--            if (raise)
-+            if (raise) {
-                 PyErr_SetFromWindowsErr(0);
--            else
--                Py_FatalError("Failed to initialized the randomized hash "
--                        "secret using CryptoGen)");
-+            }
-             return -1;
-         }
-         buffer += chunk;
-@@ -76,58 +77,23 @@ win32_urandom(unsigned char *buffer, Py_
-     return 0;
- }
- 
--/* Issue #25003: Don't use getentropy() on Solaris (available since
-- * Solaris 11.3), it is blocking whereas os.urandom() should not block. */
--#elif defined(HAVE_GETENTROPY) && !defined(sun)
--#define PY_GETENTROPY 1
--
--/* Fill buffer with size pseudo-random bytes generated by getentropy().
--   Return 0 on success, or raise an exception and return -1 on error.
--
--   If fatal is nonzero, call Py_FatalError() instead of raising an exception
--   on error. */
--static int
--py_getentropy(unsigned char *buffer, Py_ssize_t size, int fatal)
--{
--    while (size > 0) {
--        Py_ssize_t len = Py_MIN(size, 256);
--        int res;
--
--        if (!fatal) {
--            Py_BEGIN_ALLOW_THREADS
--            res = getentropy(buffer, len);
--            Py_END_ALLOW_THREADS
--
--            if (res < 0) {
--                PyErr_SetFromErrno(PyExc_OSError);
--                return -1;
--            }
--        }
--        else {
--            res = getentropy(buffer, len);
--            if (res < 0)
--                Py_FatalError("getentropy() failed");
--        }
--
--        buffer += len;
--        size -= len;
--    }
--    return 0;
--}
--
--#else
-+#else /* !MS_WINDOWS */
- 
- #if defined(HAVE_GETRANDOM) || defined(HAVE_GETRANDOM_SYSCALL)
- #define PY_GETRANDOM 1
- 
--/* Call getrandom()
-+/* Call getrandom() to get random bytes:
-+
-    - Return 1 on success
--   - Return 0 if getrandom() syscall is not available (failed with ENOSYS or
--     EPERM) or if getrandom(GRND_NONBLOCK) failed with EAGAIN (system urandom
--     not initialized yet) and raise=0.
-+   - Return 0 if getrandom() is not available (failed with ENOSYS or EPERM),
-+     or if getrandom(GRND_NONBLOCK) failed with EAGAIN (system urandom not
-+     initialized yet).
-    - Raise an exception (if raise is non-zero) and return -1 on error:
--     getrandom() failed with EINTR and the Python signal handler raised an
--     exception, or getrandom() failed with a different error. */
-+     if getrandom() failed with EINTR, raise is non-zero and the Python signal
-+     handler raised an exception, or if getrandom() failed with a different
-+     error.
-+
-+   getrandom() is retried if it failed with EINTR: interrupted by a signal. */
- static int
- py_getrandom(void *buffer, Py_ssize_t size, int raise)
- {
-@@ -142,16 +108,19 @@ py_getrandom(void *buffer, Py_ssize_t si
-      * see https://bugs.python.org/issue26839. To avoid this, use the
-      * GRND_NONBLOCK flag. */
-     const int flags = GRND_NONBLOCK;
-+    char *dest;
-     long n;
- 
-     if (!getrandom_works) {
-         return 0;
-     }
- 
-+    dest = buffer;
-     while (0 < size) {
- #ifdef sun
-         /* Issue #26735: On Solaris, getrandom() is limited to returning up
--           to 1024 bytes */
-+           to 1024 bytes. Call it multiple times if more bytes are
-+           requested. */
-         n = Py_MIN(size, 1024);
- #else
-         n = Py_MIN(size, LONG_MAX);
-@@ -161,34 +130,35 @@ py_getrandom(void *buffer, Py_ssize_t si
- #ifdef HAVE_GETRANDOM
-         if (raise) {
-             Py_BEGIN_ALLOW_THREADS
--            n = getrandom(buffer, n, flags);
-+            n = getrandom(dest, n, flags);
-             Py_END_ALLOW_THREADS
-         }
-         else {
--            n = getrandom(buffer, n, flags);
-+            n = getrandom(dest, n, flags);
-         }
- #else
-         /* On Linux, use the syscall() function because the GNU libc doesn't
--         * expose the Linux getrandom() syscall yet. See:
--         * https://sourceware.org/bugzilla/show_bug.cgi?id=17252 */
-+           expose the Linux getrandom() syscall yet. See:
-+           https://sourceware.org/bugzilla/show_bug.cgi?id=17252 */
-         if (raise) {
-             Py_BEGIN_ALLOW_THREADS
--            n = syscall(SYS_getrandom, buffer, n, flags);
-+            n = syscall(SYS_getrandom, dest, n, flags);
-             Py_END_ALLOW_THREADS
-         }
-         else {
--            n = syscall(SYS_getrandom, buffer, n, flags);
-+            n = syscall(SYS_getrandom, dest, n, flags);
-         }
- #endif
- 
-         if (n < 0) {
--            /* ENOSYS: getrandom() syscall not supported by the kernel (but
--             * maybe supported by the host which built Python). EPERM:
--             * getrandom() syscall blocked by SECCOMP or something else. */
-+            /* ENOSYS: the syscall is not supported by the kernel.
-+               EPERM: the syscall is blocked by a security policy (ex: SECCOMP)
-+               or something else. */
-             if (errno == ENOSYS || errno == EPERM) {
-                 getrandom_works = 0;
-                 return 0;
-             }
-+
-             if (errno == EAGAIN) {
-                 /* getrandom(GRND_NONBLOCK) fails with EAGAIN if the system
-                    urandom is not initialiazed yet. In this case, fall back on
-@@ -202,32 +172,101 @@ py_getrandom(void *buffer, Py_ssize_t si
-             }
- 
-             if (errno == EINTR) {
--                if (PyErr_CheckSignals()) {
--                    if (!raise) {
--                        Py_FatalError("getrandom() interrupted by a signal");
-+                if (raise) {
-+                    if (PyErr_CheckSignals()) {
-+                        return -1;
-                     }
--                    return -1;
-                 }
- 
--                /* retry getrandom() */
-+                /* retry getrandom() if it was interrupted by a signal */
-                 continue;
-             }
- 
-             if (raise) {
-                 PyErr_SetFromErrno(PyExc_OSError);
-             }
--            else {
--                Py_FatalError("getrandom() failed");
-+            return -1;
-+        }
-+
-+        dest += n;
-+        size -= n;
-+    }
-+    return 1;
-+}
-+
-+#elif defined(HAVE_GETENTROPY)
-+#define PY_GETENTROPY 1
-+
-+/* Fill buffer with size pseudo-random bytes generated by getentropy():
-+
-+   - Return 1 on success
-+   - Return 0 if getentropy() syscall is not available (failed with ENOSYS or
-+     EPERM).
-+   - Raise an exception (if raise is non-zero) and return -1 on error:
-+     if getentropy() failed with EINTR, raise is non-zero and the Python signal
-+     handler raised an exception, or if getentropy() failed with a different
-+     error.
-+
-+   getentropy() is retried if it failed with EINTR: interrupted by a signal. */
-+static int
-+py_getentropy(char *buffer, Py_ssize_t size, int raise)
-+{
-+    /* Is getentropy() supported by the running kernel? Set to 0 if
-+       getentropy() failed with ENOSYS or EPERM. */
-+    static int getentropy_works = 1;
-+
-+    if (!getentropy_works) {
-+        return 0;
-+    }
-+
-+    while (size > 0) {
-+        /* getentropy() is limited to returning up to 256 bytes. Call it
-+           multiple times if more bytes are requested. */
-+        Py_ssize_t len = Py_MIN(size, 256);
-+        int res;
-+
-+        if (raise) {
-+            Py_BEGIN_ALLOW_THREADS
-+            res = getentropy(buffer, len);
-+            Py_END_ALLOW_THREADS
-+        }
-+        else {
-+            res = getentropy(buffer, len);
-+        }
-+
-+        if (res < 0) {
-+            /* ENOSYS: the syscall is not supported by the running kernel.
-+               EPERM: the syscall is blocked by a security policy (ex: SECCOMP)
-+               or something else. */
-+            if (errno == ENOSYS || errno == EPERM) {
-+                getentropy_works = 0;
-+                return 0;
-+            }
-+
-+            if (errno == EINTR) {
-+                if (raise) {
-+                    if (PyErr_CheckSignals()) {
-+                        return -1;
-+                    }
-+                }
-+
-+                /* retry getentropy() if it was interrupted by a signal */
-+                continue;
-+            }
-+
-+            if (raise) {
-+                PyErr_SetFromErrno(PyExc_OSError);
-             }
-             return -1;
-         }
- 
--        buffer += n;
--        size -= n;
-+        buffer += len;
-+        size -= len;
-     }
-     return 1;
- }
--#endif
-+#endif /* defined(HAVE_GETENTROPY) && !defined(sun) */
-+
- 
- static struct {
-     int fd;
-@@ -235,136 +274,123 @@ static struct {
-     ino_t st_ino;
- } urandom_cache = { -1 };
- 
-+/* Read random bytes from the /dev/urandom device:
- 
--/* Read 'size' random bytes from py_getrandom(). Fall back on reading from
--   /dev/urandom if getrandom() is not available.
-+   - Return 0 on success
-+   - Raise an exception (if raise is non-zero) and return -1 on error
- 
--   Call Py_FatalError() on error. */
--static void
--dev_urandom_noraise(unsigned char *buffer, Py_ssize_t size)
-+   Possible causes of errors:
-+
-+   - open() failed with ENOENT, ENXIO, ENODEV, EACCES: the /dev/urandom device
-+     was not found. For example, it was removed manually or not exposed in a
-+     chroot or container.
-+   - open() failed with a different error
-+   - fstat() failed
-+   - read() failed or returned 0
-+
-+   read() is retried if it failed with EINTR: interrupted by a signal.
-+
-+   The file descriptor of the device is kept open between calls to avoid using
-+   many file descriptors when run in parallel from multiple threads:
-+   see the issue #18756.
-+
-+   st_dev and st_ino fields of the file descriptor (from fstat()) are cached to
-+   check if the file descriptor was replaced by a different file (which is
-+   likely a bug in the application): see the issue #21207.
-+
-+   If the file descriptor was closed or replaced, open a new file descriptor
-+   but don't close the old file descriptor: it probably points to something
-+   important for some third-party code. */
-+static int
-+dev_urandom(char *buffer, Py_ssize_t size, int raise)
- {
-     int fd;
-     Py_ssize_t n;
- 
--    assert (0 < size);
-+    if (raise) {
-+        struct _Py_stat_struct st;
- 
--#ifdef PY_GETRANDOM
--    if (py_getrandom(buffer, size, 0) == 1) {
--        return;
-+        if (urandom_cache.fd >= 0) {
-+            /* Does the fd point to the same thing as before? (issue #21207) */
-+            if (_Py_fstat_noraise(urandom_cache.fd, &st)
-+                || st.st_dev != urandom_cache.st_dev
-+                || st.st_ino != urandom_cache.st_ino) {
-+                /* Something changed: forget the cached fd (but don't close it,
-+                   since it probably points to something important for some
-+                   third-party code). */
-+                urandom_cache.fd = -1;
-+            }
-+        }
-+        if (urandom_cache.fd >= 0)
-+            fd = urandom_cache.fd;
-+        else {
-+            fd = _Py_open("/dev/urandom", O_RDONLY);
-+            if (fd < 0) {
-+                if (errno == ENOENT || errno == ENXIO ||
-+                    errno == ENODEV || errno == EACCES) {
-+                    PyErr_SetString(PyExc_NotImplementedError,
-+                                    "/dev/urandom (or equivalent) not found");
-+                }
-+                /* otherwise, keep the OSError exception raised by _Py_open() */
-+                return -1;
-+            }
-+            if (urandom_cache.fd >= 0) {
-+                /* urandom_fd was initialized by another thread while we were
-+                   not holding the GIL, keep it. */
-+                close(fd);
-+                fd = urandom_cache.fd;
-+            }
-+            else {
-+                if (_Py_fstat(fd, &st)) {
-+                    close(fd);
-+                    return -1;
-+                }
-+                else {
-+                    urandom_cache.fd = fd;
-+                    urandom_cache.st_dev = st.st_dev;
-+                    urandom_cache.st_ino = st.st_ino;
-+                }
-+            }
-+        }
-+
-+        do {
-+            n = _Py_read(fd, buffer, (size_t)size);
-+            if (n == -1)
-+                return -1;
-+            if (n == 0) {
-+                PyErr_Format(PyExc_RuntimeError,
-+                        "Failed to read %zi bytes from /dev/urandom",
-+                        size);
-+                return -1;
-+            }
-+
-+            buffer += n;
-+            size -= n;
-+        } while (0 < size);
-     }
--    /* getrandom() failed with ENOSYS or EPERM,
--       fall back on reading /dev/urandom */
--#endif
--
--    fd = _Py_open_noraise("/dev/urandom", O_RDONLY);
--    if (fd < 0) {
--        Py_FatalError("Failed to open /dev/urandom");
--    }
--
--    while (0 < size)
--    {
--        do {
--            n = read(fd, buffer, (size_t)size);
--        } while (n < 0 && errno == EINTR);
--
--        if (n <= 0) {
--            /* read() failed or returned 0 bytes */
--            Py_FatalError("Failed to read bytes from /dev/urandom");
--            break;
--        }
--        buffer += n;
--        size -= n;
--    }
--    close(fd);
--}
--
--/* Read 'size' random bytes from py_getrandom(). Fall back on reading from
--   /dev/urandom if getrandom() is not available.
--
--   Return 0 on success. Raise an exception and return -1 on error. */
--static int
--dev_urandom_python(char *buffer, Py_ssize_t size)
--{
--    int fd;
--    Py_ssize_t n;
--    struct _Py_stat_struct st;
--#ifdef PY_GETRANDOM
--    int res;
--#endif
--
--    if (size <= 0)
--        return 0;
--
--#ifdef PY_GETRANDOM
--    res = py_getrandom(buffer, size, 1);
--    if (res < 0) {
--        return -1;
--    }
--    if (res == 1) {
--        return 0;
--    }
--    /* getrandom() failed with ENOSYS or EPERM,
--       fall back on reading /dev/urandom */
--#endif
--
--    if (urandom_cache.fd >= 0) {
--        /* Does the fd point to the same thing as before? (issue #21207) */
--        if (_Py_fstat_noraise(urandom_cache.fd, &st)
--            || st.st_dev != urandom_cache.st_dev
--            || st.st_ino != urandom_cache.st_ino) {
--            /* Something changed: forget the cached fd (but don't close it,
--               since it probably points to something important for some
--               third-party code). */
--            urandom_cache.fd = -1;
--        }
--    }
--    if (urandom_cache.fd >= 0)
--        fd = urandom_cache.fd;
-     else {
--        fd = _Py_open("/dev/urandom", O_RDONLY);
-+        fd = _Py_open_noraise("/dev/urandom", O_RDONLY);
-         if (fd < 0) {
--            if (errno == ENOENT || errno == ENXIO ||
--                errno == ENODEV || errno == EACCES)
--                PyErr_SetString(PyExc_NotImplementedError,
--                                "/dev/urandom (or equivalent) not found");
--            /* otherwise, keep the OSError exception raised by _Py_open() */
-             return -1;
-         }
--        if (urandom_cache.fd >= 0) {
--            /* urandom_fd was initialized by another thread while we were
--               not holding the GIL, keep it. */
--            close(fd);
--            fd = urandom_cache.fd;
--        }
--        else {
--            if (_Py_fstat(fd, &st)) {
-+
-+        while (0 < size)
-+        {
-+            do {
-+                n = read(fd, buffer, (size_t)size);
-+            } while (n < 0 && errno == EINTR);
-+
-+            if (n <= 0) {
-+                /* stop on error or if read(size) returned 0 */
-                 close(fd);
-                 return -1;
-             }
--            else {
--                urandom_cache.fd = fd;
--                urandom_cache.st_dev = st.st_dev;
--                urandom_cache.st_ino = st.st_ino;
--            }
-+
-+            buffer += n;
-+            size -= n;
-         }
-+        close(fd);
-     }
--
--    do {
--        n = _Py_read(fd, buffer, (size_t)size);
--        if (n == -1) {
--            return -1;
--        }
--        if (n == 0) {
--            PyErr_Format(PyExc_RuntimeError,
--                    "Failed to read %zi bytes from /dev/urandom",
--                    size);
--            return -1;
--        }
--
--        buffer += n;
--        size -= n;
--    } while (0 < size);
--
-     return 0;
- }
- 
-@@ -376,8 +402,8 @@ dev_urandom_close(void)
-         urandom_cache.fd = -1;
-     }
- }
-+#endif /* !MS_WINDOWS */
- 
--#endif
- 
- /* Fill buffer with pseudo-random bytes generated by a linear congruent
-    generator (LCG):
-@@ -400,29 +426,98 @@ lcg_urandom(unsigned int x0, unsigned ch
-     }
- }
- 
-+/* Read random bytes:
-+
-+   - Return 0 on success
-+   - Raise an exception (if raise is non-zero) and return -1 on error
-+
-+   Used sources of entropy ordered by preference, preferred source first:
-+
-+   - CryptGenRandom() on Windows
-+   - getrandom() function (ex: Linux and Solaris): call py_getrandom()
-+   - getentropy() function (ex: OpenBSD): call py_getentropy()
-+   - /dev/urandom device
-+
-+   Read from the /dev/urandom device if getrandom() or getentropy() function
-+   is not available or does not work.
-+
-+   Prefer getrandom() over getentropy() because getrandom() supports blocking
-+   and non-blocking mode and Python requires non-blocking RNG at startup to
-+   initialize its hash secret: see the PEP 524.
-+
-+   Prefer getrandom() and getentropy() over reading directly /dev/urandom
-+   because these functions don't need file descriptors and so avoid ENFILE or
-+   EMFILE errors (too many open files): see the issue #18756.
-+
-+   Only use RNG running in the kernel. They are more secure because it is
-+   harder to get the internal state of a RNG running in the kernel land than a
-+   RNG running in the user land. The kernel has a direct access to the hardware
-+   and has access to hardware RNG, they are used as entropy sources.
-+
-+   Note: the OpenSSL RAND_pseudo_bytes() function does not automatically reseed
-+   its RNG on fork(), two child processes (with the same pid) generate the same
-+   random numbers: see issue #18747. Kernel RNGs don't have this issue,
-+   they have access to good quality entropy sources.
-+
-+   If raise is zero:
-+
-+   - Don't raise an exception on error
-+   - Don't call the Python signal handler (don't call PyErr_CheckSignals()) if
-+     a function fails with EINTR: retry directly the interrupted function
-+   - Don't release the GIL to call functions.
-+*/
-+static int
-+pyurandom(void *buffer, Py_ssize_t size, int raise)
-+{
-+#if defined(PY_GETRANDOM) || defined(PY_GETENTROPY)
-+    int res;
-+#endif
-+
-+    if (size < 0) {
-+        if (raise) {
-+            PyErr_Format(PyExc_ValueError,
-+                         "negative argument not allowed");
-+        }
-+        return -1;
-+    }
-+
-+    if (size == 0) {
-+        return 0;
-+    }
-+
-+#ifdef MS_WINDOWS
-+    return win32_urandom((unsigned char *)buffer, size, raise);
-+#else
-+
-+#if defined(PY_GETRANDOM) || defined(PY_GETENTROPY)
-+#ifdef PY_GETRANDOM
-+    res = py_getrandom(buffer, size, raise);
-+#else
-+    res = py_getentropy(buffer, size, raise);
-+#endif
-+    if (res < 0) {
-+        return -1;
-+    }
-+    if (res == 1) {
-+        return 0;
-+    }
-+    /* getrandom() or getentropy() function is not available: failed with
-+       ENOSYS, EPERM or EAGAIN. Fall back on reading from /dev/urandom. */
-+#endif
-+
-+    return dev_urandom(buffer, size, raise);
-+#endif
-+}
-+
- /* Fill buffer with size pseudo-random bytes from the operating system random
-    number generator (RNG). It is suitable for most cryptographic purposes
-    except long living private keys for asymmetric encryption.
- 
--   Return 0 on success, raise an exception and return -1 on error. */
-+   Return 0 on success. Raise an exception and return -1 on error. */
- int
- _PyOS_URandom(void *buffer, Py_ssize_t size)
- {
--    if (size < 0) {
--        PyErr_Format(PyExc_ValueError,
--                     "negative argument not allowed");
--        return -1;
--    }
--    if (size == 0)
--        return 0;
--
--#ifdef MS_WINDOWS
--    return win32_urandom((unsigned char *)buffer, size, 1);
--#elif defined(PY_GETENTROPY)
--    return py_getentropy(buffer, size, 0);
--#else
--    return dev_urandom_python((char*)buffer, size);
--#endif
-+    return pyurandom(buffer, size, 1);
- }
- 
- void
-@@ -463,13 +558,14 @@ void
-         }
-     }
-     else {
--#ifdef MS_WINDOWS
--        (void)win32_urandom(secret, secret_size, 0);
--#elif defined(PY_GETENTROPY)
--        (void)py_getentropy(secret, secret_size, 1);
--#else
--        dev_urandom_noraise(secret, secret_size);
--#endif
-+        int res;
-+
-+        /* _PyRandom_Init() is called very early in the Python initialization
-+           and so exceptions cannot be used (use raise=0). */
-+        res = pyurandom(secret, secret_size, 0);
-+        if (res < 0) {
-+            Py_FatalError("failed to get random numbers to initialize Python");
-+        }
-     }
- }
- 
-@@ -481,8 +577,6 @@ void
-         CryptReleaseContext(hCryptProv, 0);
-         hCryptProv = 0;
-     }
--#elif defined(PY_GETENTROPY)
--    /* nothing to clean */
- #else
-     dev_urandom_close();
- #endif
-