"Test posix functions"

from test import support
from test.support.script_helper import assert_python_ok

# Skip these tests if there is no posix module.
posix = support.import_module('posix')

import errno
import sys
import signal
import time
import os
import platform
import pwd
import stat
import tempfile
import unittest
import warnings
import textwrap

_DUMMY_SYMLINK = os.path.join(tempfile.gettempdir(),
                              support.TESTFN + '-dummy-symlink')

requires_32b = unittest.skipUnless(sys.maxsize < 2**32,
        'test is only meaningful on 32-bit builds')

def _supports_sched():
    if not hasattr(posix, 'sched_getscheduler'):
        return False
    try:
        posix.sched_getscheduler(0)
    except OSError as e:
        if e.errno == errno.ENOSYS:
            return False
    return True

requires_sched = unittest.skipUnless(_supports_sched(), 'requires POSIX scheduler API')

class PosixTester(unittest.TestCase):

    def setUp(self):
        # create empty file
        fp = open(support.TESTFN, 'w+')
        fp.close()
        self.teardown_files = [ support.TESTFN ]
        self._warnings_manager = support.check_warnings()
        self._warnings_manager.__enter__()
        warnings.filterwarnings('ignore', '.* potential security risk .*',
                                RuntimeWarning)

    def tearDown(self):
        for teardown_file in self.teardown_files:
            support.unlink(teardown_file)
        self._warnings_manager.__exit__(None, None, None)

    def testNoArgFunctions(self):
        # test posix functions which take no arguments and have
        # no side-effects which we need to cleanup (e.g., fork, wait, abort)
        NO_ARG_FUNCTIONS = [ "ctermid", "getcwd", "getcwdb", "uname",
                             "times", "getloadavg",
                             "getegid", "geteuid", "getgid", "getgroups",
                             "getpid", "getpgrp", "getppid", "getuid", "sync",
                           ]

        for name in NO_ARG_FUNCTIONS:
            posix_func = getattr(posix, name, None)
            if posix_func is not None:
                posix_func()
                self.assertRaises(TypeError, posix_func, 1)

    @unittest.skipUnless(hasattr(posix, 'getresuid'),
                         'test needs posix.getresuid()')
    def test_getresuid(self):
        user_ids = posix.getresuid()
        self.assertEqual(len(user_ids), 3)
        for val in user_ids:
            self.assertGreaterEqual(val, 0)

    @unittest.skipUnless(hasattr(posix, 'getresgid'),
                         'test needs posix.getresgid()')
    def test_getresgid(self):
        group_ids = posix.getresgid()
        self.assertEqual(len(group_ids), 3)
        for val in group_ids:
            self.assertGreaterEqual(val, 0)

    @unittest.skipUnless(hasattr(posix, 'setresuid'),
                         'test needs posix.setresuid()')
    def test_setresuid(self):
        current_user_ids = posix.getresuid()
        self.assertIsNone(posix.setresuid(*current_user_ids))
        # -1 means don't change that value.
        self.assertIsNone(posix.setresuid(-1, -1, -1))

    @unittest.skipUnless(hasattr(posix, 'setresuid'),
                         'test needs posix.setresuid()')
    def test_setresuid_exception(self):
        # Don't do this test if someone is silly enough to run us as root.
        current_user_ids = posix.getresuid()
        if 0 not in current_user_ids:
            new_user_ids = (current_user_ids[0]+1, -1, -1)
            self.assertRaises(OSError, posix.setresuid, *new_user_ids)

    @unittest.skipUnless(hasattr(posix, 'setresgid'),
                         'test needs posix.setresgid()')
    def test_setresgid(self):
        current_group_ids = posix.getresgid()
        self.assertIsNone(posix.setresgid(*current_group_ids))
        # -1 means don't change that value.
        self.assertIsNone(posix.setresgid(-1, -1, -1))

    @unittest.skipUnless(hasattr(posix, 'setresgid'),
                         'test needs posix.setresgid()')
    def test_setresgid_exception(self):
        # Don't do this test if someone is silly enough to run us as root.
        current_group_ids = posix.getresgid()
        if 0 not in current_group_ids:
            new_group_ids = (current_group_ids[0]+1, -1, -1)
            self.assertRaises(OSError, posix.setresgid, *new_group_ids)

    @unittest.skipUnless(hasattr(posix, 'initgroups'),
                         "test needs os.initgroups()")
    def test_initgroups(self):
        # It takes a string and an integer; check that it raises a TypeError
        # for other argument lists.
        self.assertRaises(TypeError, posix.initgroups)
        self.assertRaises(TypeError, posix.initgroups, None)
        self.assertRaises(TypeError, posix.initgroups, 3, "foo")
        self.assertRaises(TypeError, posix.initgroups, "foo", 3, object())

        # If a non-privileged user invokes it, it should fail with OSError
        # EPERM.
        if os.getuid() != 0:
            try:
                name = pwd.getpwuid(posix.getuid()).pw_name
            except KeyError:
                # the current UID may not have a pwd entry
                raise unittest.SkipTest("need a pwd entry")
            try:
                posix.initgroups(name, 13)
            except OSError as e:
                self.assertEqual(e.errno, errno.EPERM)
            else:
                self.fail("Expected OSError to be raised by initgroups")

    @unittest.skipUnless(hasattr(posix, 'statvfs'),
                         'test needs posix.statvfs()')
    def test_statvfs(self):
        self.assertTrue(posix.statvfs(os.curdir))

    @unittest.skipUnless(hasattr(posix, 'fstatvfs'),
                         'test needs posix.fstatvfs()')
    def test_fstatvfs(self):
        fp = open(support.TESTFN)
        try:
            self.assertTrue(posix.fstatvfs(fp.fileno()))
            self.assertTrue(posix.statvfs(fp.fileno()))
        finally:
            fp.close()

    @unittest.skipUnless(hasattr(posix, 'ftruncate'),
                         'test needs posix.ftruncate()')
    def test_ftruncate(self):
        fp = open(support.TESTFN, 'w+')
        try:
            # we need to have some data to truncate
            fp.write('test')
            fp.flush()
            posix.ftruncate(fp.fileno(), 0)
        finally:
            fp.close()

    @unittest.skipUnless(hasattr(posix, 'truncate'), "test needs posix.truncate()")
    def test_truncate(self):
        with open(support.TESTFN, 'w') as fp:
            fp.write('test')
            fp.flush()
        posix.truncate(support.TESTFN, 0)

    @unittest.skipUnless(getattr(os, 'execve', None) in os.supports_fd, "test needs execve() to support the fd parameter")
    @unittest.skipUnless(hasattr(os, 'fork'), "test needs os.fork()")
    @unittest.skipUnless(hasattr(os, 'waitpid'), "test needs os.waitpid()")
    def test_fexecve(self):
        fp = os.open(sys.executable, os.O_RDONLY)
        try:
            pid = os.fork()
            if pid == 0:
                os.chdir(os.path.split(sys.executable)[0])
                posix.execve(fp, [sys.executable, '-c', 'pass'], os.environ)
            else:
                self.assertEqual(os.waitpid(pid, 0), (pid, 0))
        finally:
            os.close(fp)


    @unittest.skipUnless(hasattr(posix, 'waitid'), "test needs posix.waitid()")
    @unittest.skipUnless(hasattr(os, 'fork'), "test needs os.fork()")
    def test_waitid(self):
        pid = os.fork()
        if pid == 0:
            os.chdir(os.path.split(sys.executable)[0])
            posix.execve(sys.executable, [sys.executable, '-c', 'pass'], os.environ)
        else:
            res = posix.waitid(posix.P_PID, pid, posix.WEXITED)
            self.assertEqual(pid, res.si_pid)

    @unittest.skipUnless(hasattr(os, 'fork'), "test needs os.fork()")
    def test_register_at_fork(self):
        with self.assertRaises(TypeError, msg="Positional args not allowed"):
            os.register_at_fork(lambda: None)
        with self.assertRaises(TypeError, msg="Args must be callable"):
            os.register_at_fork(before=2)
        with self.assertRaises(TypeError, msg="Args must be callable"):
            os.register_at_fork(after_in_child="three")
        with self.assertRaises(TypeError, msg="Args must be callable"):
            os.register_at_fork(after_in_parent=b"Five")
        with self.assertRaises(TypeError, msg="Args must not be None"):
            os.register_at_fork(before=None)
        with self.assertRaises(TypeError, msg="Args must not be None"):
            os.register_at_fork(after_in_child=None)
        with self.assertRaises(TypeError, msg="Args must not be None"):
            os.register_at_fork(after_in_parent=None)
        with self.assertRaises(TypeError, msg="Invalid arg was allowed"):
            # Ensure a combination of valid and invalid is an error.
            os.register_at_fork(before=None, after_in_parent=lambda: 3)
        with self.assertRaises(TypeError, msg="Invalid arg was allowed"):
            # Ensure a combination of valid and invalid is an error.
            os.register_at_fork(before=lambda: None, after_in_child='')
        # We test actual registrations in their own process so as not to
        # pollute this one.  There is no way to unregister for cleanup.
        code = """if 1:
            import os

            r, w = os.pipe()
            fin_r, fin_w = os.pipe()

            os.register_at_fork(before=lambda: os.write(w, b'A'))
            os.register_at_fork(after_in_parent=lambda: os.write(w, b'C'))
            os.register_at_fork(after_in_child=lambda: os.write(w, b'E'))
            os.register_at_fork(before=lambda: os.write(w, b'B'),
                                after_in_parent=lambda: os.write(w, b'D'),
                                after_in_child=lambda: os.write(w, b'F'))

            pid = os.fork()
            if pid == 0:
                # At this point, after-forkers have already been executed
                os.close(w)
                # Wait for parent to tell us to exit
                os.read(fin_r, 1)
                os._exit(0)
            else:
                try:
                    os.close(w)
                    with open(r, "rb") as f:
                        data = f.read()
                        assert len(data) == 6, data
                        # Check before-fork callbacks
                        assert data[:2] == b'BA', data
                        # Check after-fork callbacks
                        assert sorted(data[2:]) == list(b'CDEF'), data
                        assert data.index(b'C') < data.index(b'D'), data
                        assert data.index(b'E') < data.index(b'F'), data
                finally:
                    os.write(fin_w, b'!')
            """
        assert_python_ok('-c', code)

    @unittest.skipUnless(hasattr(posix, 'lockf'), "test needs posix.lockf()")
    def test_lockf(self):
        fd = os.open(support.TESTFN, os.O_WRONLY | os.O_CREAT)
        try:
            os.write(fd, b'test')
            os.lseek(fd, 0, os.SEEK_SET)
            posix.lockf(fd, posix.F_LOCK, 4)
            # section is locked
            posix.lockf(fd, posix.F_ULOCK, 4)
        finally:
            os.close(fd)

    @unittest.skipUnless(hasattr(posix, 'pread'), "test needs posix.pread()")
    def test_pread(self):
        fd = os.open(support.TESTFN, os.O_RDWR | os.O_CREAT)
        try:
            os.write(fd, b'test')
            os.lseek(fd, 0, os.SEEK_SET)
            self.assertEqual(b'es', posix.pread(fd, 2, 1))
            # the first pread() shouldn't disturb the file offset
            self.assertEqual(b'te', posix.read(fd, 2))
        finally:
            os.close(fd)

    @unittest.skipUnless(hasattr(posix, 'preadv'), "test needs posix.preadv()")
    def test_preadv(self):
        fd = os.open(support.TESTFN, os.O_RDWR | os.O_CREAT)
        try:
            os.write(fd, b'test1tt2t3t5t6t6t8')
            buf = [bytearray(i) for i in [5, 3, 2]]
            self.assertEqual(posix.preadv(fd, buf, 3), 10)
            self.assertEqual([b't1tt2', b't3t', b'5t'], list(buf))
        finally:
            os.close(fd)

    @unittest.skipUnless(hasattr(posix, 'preadv'), "test needs posix.preadv()")
    @unittest.skipUnless(hasattr(posix, 'RWF_HIPRI'), "test needs posix.RWF_HIPRI")
    def test_preadv_flags(self):
        fd = os.open(support.TESTFN, os.O_RDWR | os.O_CREAT)
        try:
            os.write(fd, b'test1tt2t3t5t6t6t8')
            buf = [bytearray(i) for i in [5, 3, 2]]
            self.assertEqual(posix.preadv(fd, buf, 3, os.RWF_HIPRI), 10)
            self.assertEqual([b't1tt2', b't3t', b'5t'], list(buf))
        except NotImplementedError:
            self.skipTest("preadv2 not available")
        except OSError as inst:
            # Is possible that the macro RWF_HIPRI was defined at compilation time
            # but the option is not supported by the kernel or the runtime libc shared
            # library.
            if inst.errno in {errno.EINVAL, errno.ENOTSUP}:
                raise unittest.SkipTest("RWF_HIPRI is not supported by the current system")
            else:
                raise
        finally:
            os.close(fd)

    @unittest.skipUnless(hasattr(posix, 'preadv'), "test needs posix.preadv()")
    @requires_32b
    def test_preadv_overflow_32bits(self):
        fd = os.open(support.TESTFN, os.O_RDWR | os.O_CREAT)
        try:
            buf = [bytearray(2**16)] * 2**15
            with self.assertRaises(OSError) as cm:
                os.preadv(fd, buf, 0)
            self.assertEqual(cm.exception.errno, errno.EINVAL)
            self.assertEqual(bytes(buf[0]), b'\0'* 2**16)
        finally:
            os.close(fd)

    @unittest.skipUnless(hasattr(posix, 'pwrite'), "test needs posix.pwrite()")
    def test_pwrite(self):
        fd = os.open(support.TESTFN, os.O_RDWR | os.O_CREAT)
        try:
            os.write(fd, b'test')
            os.lseek(fd, 0, os.SEEK_SET)
            posix.pwrite(fd, b'xx', 1)