On my FreeBSD 13 VM, the test is skipped:

vstinner@freebsd$ ./python -m test -v test_os -m test_get_set_inheritable_o_path
== CPython 3.11.0a0 (heads/main:938e84b4fa, Aug 6 2021, 10:46:32) [Clang 11.0.1 (git@github.com:llvm/llvm-project.git llvmorg-11.0.1-0-g43ff75f2c3
== FreeBSD-13.0-RELEASE-amd64-64bit-ELF little-endian
(...)
test_get_set_inheritable_o_path (test.test_os.FDInheritanceTests) ... skipped 'need os.O_PATH'

It seems like O_PATH was introduced in FreeBSD 14 CURRENT, but the test fails.

Code of the test:

    @unittest.skipUnless(hasattr(os, 'O_PATH'), "need os.O_PATH")
    def test_get_set_inheritable_o_path(self):
        fd = os.open(__file__, os.O_PATH)
        self.addCleanup(os.close, fd)
        self.assertEqual(os.get_inheritable(fd), False)

        os.set_inheritable(fd, True)  # <==== OSError: [Errno 9] Bad file descriptor
        self.assertEqual(os.get_inheritable(fd), True)

        os.set_inheritable(fd, False)
        self.assertEqual(os.get_inheritable(fd), False)

os.set_inheritable() calls _Py_set_inheritable() whichs has multiple implementations:

* ioctl(fd, FIONCLEX, NULL)
* fcntl(fd, F_GETFD) + fcntl(fd, F_SETFD, new_flags)

Linux has a special code path:

#ifdef __linux__
        if (errno == EBADF) {
            // On Linux, ioctl(FIOCLEX) will fail with EBADF for O_PATH file descriptors
            // Fall through to the fcntl() path
        }
        else
#endif

Maybe we should just enable now this code path on FreeBSD as well.


== test.pythoninto of the last successful build 654 ==

datetime.datetime.now: 2021-08-01 01:15:06.918625

os.uname: posix.uname_result(sysname='FreeBSD', nodename='140-CURRENT-amd64-564d', release='14.0-CURRENT', version='FreeBSD 14.0-CURRENT #14 main-n245176-8742817ba62: Tue Mar  2 03:48:10 UTC 2021     root@140-CURRENT-amd64:/usr/obj/usr/src/amd64.amd64/sys/GENERIC-NODEBUG', machine='amd64')

== test.pythoninto of the failed build 655 ==

datetime.datetime.now: 2021-08-04 09:56:34.287999

os.uname: posix.uname_result(sysname='FreeBSD', nodename='140-CURRENT-amd64-564d', release='14.0-CURRENT', version='FreeBSD 14.0-CURRENT #0 main-n248401-de0c7fbe280: Mon Aug  2 02:42:31 UTC 2021     root@140-CURRENT-amd64-564d:/usr/obj/usr/src/amd64.amd64/sys/GENERIC-NODEBUG', machine='amd64')