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try:
    __graalpython__.posix_module_backend()
except:
    class GP:
        def posix_module_backend(self):
            return 'cpython'
    __graalpython__ = GP()

import fcntl
import os
import subprocess
import tempfile
import time
import unittest
import sys

PREFIX = 'select_graalpython_test'
TEMP_DIR = tempfile.gettempdir()
TEST_FILENAME = f'{PREFIX}_{os.getpid()}_tmp_fcntl'
TEST_FILENAME_FULL_PATH = os.path.join(TEMP_DIR, TEST_FILENAME)

def log(msg):
    # print(msg)
    pass

def python_flock_blocks_sh_flock(python_flock_type, sh_flock_type):
    os.close(os.open(TEST_FILENAME_FULL_PATH, os.O_WRONLY | os.O_CREAT))
    file = os.open(TEST_FILENAME_FULL_PATH, os.O_WRONLY)
    try:
        fcntl.flock(file, python_flock_type)
        p = subprocess.Popen("flock -%s %s -c 'exit 42'" % (sh_flock_type, TEST_FILENAME_FULL_PATH), shell=True)
        log("sleeping...")
        time.sleep(0.25)
        assert p.poll() is None # the process should be still waiting for the lock
        log("unlocking the file...")
        fcntl.flock(file, fcntl.LOCK_UN) # release the lock
        log("checking the retcode...")
        time.sleep(0.25)
        assert p.poll() == 42
        log(f"{p.returncode=}")
    finally:
        fcntl.flock(file, fcntl.LOCK_UN)
        os.close(file)

class FcntlTests(unittest.TestCase):
    @unittest.skipUnless(__graalpython__.posix_module_backend() != 'java', 'No support in Truffle API (GR-28740)')
    @unittest.skipUnless(sys.platform != 'darwin', 'MacOSX does not have flock utility')
    def test_flock_x_and_x(self):
        python_flock_blocks_sh_flock(fcntl.LOCK_EX, 'x')

    @unittest.skipUnless(__graalpython__.posix_module_backend() != 'java', 'No support in Truffle API (GR-28740)')
    @unittest.skipUnless(sys.platform != 'darwin', 'MacOSX does not have flock utility')
    def test_flock_x_and_s(self):
        python_flock_blocks_sh_flock(fcntl.LOCK_EX, 's')

    @unittest.skipUnless(__graalpython__.posix_module_backend() != 'java', 'No support in Truffle API (GR-28740)')
    @unittest.skipUnless(sys.platform != 'darwin', 'MacOSX does not have flock utility')
    def test_flock_s_and_x(self):
        python_flock_blocks_sh_flock(fcntl.LOCK_SH, 'x')

    @unittest.skipUnless(__graalpython__.posix_module_backend() != 'java', 'No support in Truffle API (GR-28740)')
    @unittest.skipUnless(sys.platform != 'darwin', 'MacOSX does not have flock utility')
    def test_flock_s_and_s(self):
        os.close(os.open(TEST_FILENAME_FULL_PATH, os.O_WRONLY | os.O_CREAT))
        file = os.open(TEST_FILENAME_FULL_PATH, os.O_WRONLY)
        try:
            fcntl.flock(file, fcntl.LOCK_SH)
            p = subprocess.Popen("flock -s %s -c 'exit 42'" % TEST_FILENAME_FULL_PATH, shell=True)
            time.sleep(0.25)
            assert p.poll() == 42
        finally:
            fcntl.flock(file, fcntl.LOCK_UN)
            os.close(file)
