Method test_set_name

Lib/test/test_mmap.py:1187–1223

(self)

    @support.requires_linux_version(5, 17, 0)
    @unittest.skipIf(support.linked_to_musl(), "musl libc issue, gh-143632")
    def test_set_name(self):
        # Test setting name on anonymous mmap
        m = mmap.mmap(-1, PAGESIZE)
        self.addCleanup(m.close)
        try:
            result = m.set_name('test_mapping')
        except OSError as exc:
            if exc.errno == errno.EINVAL:
                # gh-142419: On Fedora, prctl(PR_SET_VMA_ANON_NAME) fails with
                # EINVAL because the kernel option CONFIG_ANON_VMA_NAME is
                # disabled.
                # See: https://bugzilla.redhat.com/show_bug.cgi?id=2302746
                self.skipTest("prctl() failed with EINVAL")
            else:
                raise
        self.assertIsNone(result)

        # Test name length limit (80 chars including prefix "cpython:mmap:" and '\0')
        # Prefix is 13 chars, so max name is 66 chars
        long_name = 'x' * 66
        result = m.set_name(long_name)
        self.assertIsNone(result)

        # Test name too long
        too_long_name = 'x' * 67
        with self.assertRaises(ValueError):
            m.set_name(too_long_name)

        # Test that file-backed mmap raises error
        with open(TESTFN, 'wb+') as f:
            f.write(b'x' * PAGESIZE)
            f.flush()
            m2 = mmap.mmap(f.fileno(), PAGESIZE)
            self.addCleanup(m2.close)

            with self.assertRaises(ValueError):
                m2.set_name('should_fail')


class LargeMmapTests(unittest.TestCase):