Python os.closerange() Examples

def test_open(self):
        test_filename = "tmp.open.test"
        fd1 = os.open(test_filename + "1", flags)

        # make sure fd+1 and fd+2 are closed
        os.closerange(fd1 + 1, fd1 + 2)

        # open should return the lowest-numbered file descriptor not currently open
        # for the process
        fd2 = os.open(test_filename + "2", flags)
        fd3 = os.open(test_filename + "3", flags)

        os.close(fd2)
        self.assertRaisesMessage(OSError, "[Errno 9] Bad file descriptor", os.lseek, fd2, os.SEEK_SET, 0)

        fd4 = os.open(test_filename + "4", flags)
        self.assertEqual(fd4, fd2)

        os.close(fd1)
        os.close(fd3)
        os.close(fd4)

        for i in range(1, 5):
            os.unlink(test_filename + str(i)) 

def test_closerange(self):
        first = os.open(test_support.TESTFN, os.O_CREAT|os.O_RDWR)
        # We must allocate two consecutive file descriptors, otherwise
        # it will mess up other file descriptors (perhaps even the three
        # standard ones).
        second = os.dup(first)
        try:
            retries = 0
            while second != first + 1:
                os.close(first)
                retries += 1
                if retries > 10:
                    # XXX test skipped
                    self.skipTest("couldn't allocate two consecutive fds")
                first, second = second, os.dup(second)
        finally:
            os.close(second)
        # close a fd that is open, and one that isn't
        os.closerange(first, first + 2)
        self.assertRaises(OSError, os.write, first, "a") 

def test_closerange(self):
        first = os.open(support.TESTFN, os.O_CREAT|os.O_RDWR)
        # We must allocate two consecutive file descriptors, otherwise
        # it will mess up other file descriptors (perhaps even the three
        # standard ones).
        second = os.dup(first)
        try:
            retries = 0
            while second != first + 1:
                os.close(first)
                retries += 1
                if retries > 10:
                    # XXX test skipped
                    self.skipTest("couldn't allocate two consecutive fds")
                first, second = second, os.dup(second)
        finally:
            os.close(second)
        # close a fd that is open, and one that isn't
        os.closerange(first, first + 2)
        self.assertRaises(OSError, os.write, first, b"a") 

def test_closerange(self):
        first = os.open(test_support.TESTFN, os.O_CREAT|os.O_RDWR)
        # We must allocate two consecutive file descriptors, otherwise
        # it will mess up other file descriptors (perhaps even the three
        # standard ones).
        second = os.dup(first)
        try:
            retries = 0
            while second != first + 1:
                os.close(first)
                retries += 1
                if retries > 10:
                    # XXX test skipped
                    self.skipTest("couldn't allocate two consecutive fds")
                first, second = second, os.dup(second)
        finally:
            os.close(second)
        # close a fd that is open, and one that isn't
        os.closerange(first, first + 2)
        self.assertRaises(OSError, os.write, first, "a") 

def test_closerange(self):
        first = os.open(support.TESTFN, os.O_CREAT|os.O_RDWR)
        # We must allocate two consecutive file descriptors, otherwise
        # it will mess up other file descriptors (perhaps even the three
        # standard ones).
        second = os.dup(first)
        try:
            retries = 0
            while second != first + 1:
                os.close(first)
                retries += 1
                if retries > 10:
                    # XXX test skipped
                    self.skipTest("couldn't allocate two consecutive fds")
                first, second = second, os.dup(second)
        finally:
            os.close(second)
        # close a fd that is open, and one that isn't
        os.closerange(first, first + 2)
        self.assertRaises(OSError, os.write, first, b"a") 

def test_closerange(self):
        first = os.open(test_support.TESTFN, os.O_CREAT|os.O_RDWR)
        # We must allocate two consecutive file descriptors, otherwise
        # it will mess up other file descriptors (perhaps even the three
        # standard ones).
        second = os.dup(first)
        try:
            retries = 0
            while second != first + 1:
                os.close(first)
                retries += 1
                if retries > 10:
                    # XXX test skipped
                    self.skipTest("couldn't allocate two consecutive fds")
                first, second = second, os.dup(second)
        finally:
            os.close(second)
        # close a fd that is open, and one that isn't
        os.closerange(first, first + 2)
        self.assertRaises(OSError, os.write, first, "a") 

def test_closerange(self):
        first = os.open(support.TESTFN, os.O_CREAT|os.O_RDWR)
        # We must allocate two consecutive file descriptors, otherwise
        # it will mess up other file descriptors (perhaps even the three
        # standard ones).
        second = os.dup(first)
        try:
            retries = 0
            while second != first + 1:
                os.close(first)
                retries += 1
                if retries > 10:
                    # XXX test skipped
                    self.skipTest("couldn't allocate two consecutive fds")
                first, second = second, os.dup(second)
        finally:
            os.close(second)
        # close a fd that is open, and one that isn't
        os.closerange(first, first + 2)
        self.assertRaises(OSError, os.write, first, b"a") 

def test_open(self):
        test_filename = "tmp.open.test"
        fd1 = os.open(test_filename + "1", flags)

        # make sure fd+1 and fd+2 are closed
        os.closerange(fd1 + 1, fd1 + 2)

        # open should return the lowest-numbered file descriptor not currently open
        # for the process
        fd2 = os.open(test_filename + "2", flags)
        fd3 = os.open(test_filename + "3", flags)

        os.close(fd2)
        self.assertRaisesMessage(OSError, "[Errno 9] Bad file descriptor", os.lseek, fd2, os.SEEK_SET, 0)

        fd4 = os.open(test_filename + "4", flags)
        self.assertEqual(fd4, fd2)

        os.close(fd1)
        os.close(fd3)
        os.close(fd4)

        for i in range(1, 5):
            os.unlink(test_filename + str(i)) 

def _close_fds(self, but):
            if hasattr(os, 'closerange'):
                os.closerange(3, but)
                os.closerange(but + 1, MAXFD)
            else:
                for i in xrange(3, MAXFD):
                    if i == but:
                        continue
                    try:
                        os.close(i)
                    except:
                        pass


        # Used as a bandaid workaround for https://bugs.python.org/issue27448
        # to prevent multiple simultaneous subprocess launches from interfering
        # with one another and leaving gc disabled. 

def test_closerange(self):
        first = os.open(test_support.TESTFN, os.O_CREAT|os.O_RDWR)
        # We must allocate two consecutive file descriptors, otherwise
        # it will mess up other file descriptors (perhaps even the three
        # standard ones).
        second = os.dup(first)
        try:
            retries = 0
            while second != first + 1:
                os.close(first)
                retries += 1
                if retries > 10:
                    # XXX test skipped
                    self.skipTest("couldn't allocate two consecutive fds")
                first, second = second, os.dup(second)
        finally:
            os.close(second)
        # close a fd that is open, and one that isn't
        os.closerange(first, first + 2)
        self.assertRaises(OSError, os.write, first, "a") 

def _close_fds(self, but):
            if hasattr(os, 'closerange'):
                os.closerange(3, but)
                os.closerange(but + 1, MAXFD)
            else:
                for i in xrange(3, MAXFD):
                    if i == but:
                        continue
                    try:
                        os.close(i)
                    except:
                        pass


        # Used as a bandaid workaround for https://bugs.python.org/issue27448
        # to prevent multiple simultaneous subprocess launches from interfering
        # with one another and leaving gc disabled. 

def _autoclose_files(shielded=None, fallback_limit=1024):
    ''' Automatically close any open file descriptors.
    
    shielded is iterable of file descriptors.
    '''
    # Process shielded.
    shielded = default_to(shielded, [])
    
    # Figure out the maximum number of files to try to close.
    # This returns a tuple of softlimit, hardlimit; the hardlimit is always
    # greater.
    softlimit, hardlimit = resource.getrlimit(resource.RLIMIT_NOFILE)
    
    # If the hard limit is infinity, we can't iterate to it.
    if hardlimit == resource.RLIM_INFINITY:
        # Check the soft limit. If it's also infinity, fallback to guess.
        if softlimit == resource.RLIM_INFINITY:
            fdlimit = fallback_limit
            
        # The soft limit is finite, so fallback to that.
        else:
            fdlimit = softlimit
            
    # The hard limit is not infinity, so prefer it.
    else:
        fdlimit = hardlimit
    
    # Skip fd 0, 1, 2, which are used by stdin, stdout, and stderr
    # (respectively)
    ranges_to_close = _make_range_tuples(
        start = 3,
        stop = fdlimit,
        exclude = shielded
    )
    for start, stop in ranges_to_close:
        # How nice of os to include this for us!
        os.closerange(start, stop) 

def test_closerange(self):
        first = os.open(test_support.TESTFN, os.O_CREAT|os.O_RDWR)
        # We must allocate two consecutive file descriptors, otherwise
        # it will mess up other file descriptors (perhaps even the three
        # standard ones).
        second = os.dup(first)
        try:
            retries = 0
            while second != first + 1:
                os.close(first)
                retries += 1
                if retries > 10:
                    # XXX test skipped
                    self.skipTest("couldn't allocate two consecutive fds")
                first, second = second, os.dup(second)
        finally:
            os.close(second)
        # close a fd that is open, and one that isn't
        os.closerange(first, first + 2)
        self.assertRaises(OSError, os.write, first, "a") 

def test_closerange(self):
        first = os.open(test_support.TESTFN, os.O_CREAT|os.O_RDWR)
        # We must allocate two consecutive file descriptors, otherwise
        # it will mess up other file descriptors (perhaps even the three
        # standard ones).
        second = os.dup(first)
        try:
            retries = 0
            while second != first + 1:
                os.close(first)
                retries += 1
                if retries > 10:
                    # XXX test skipped
                    self.skipTest("couldn't allocate two consecutive fds")
                first, second = second, os.dup(second)
        finally:
            os.close(second)
        # close a fd that is open, and one that isn't
        os.closerange(first, first + 2)
        self.assertRaises(OSError, os.write, first, "a") 

def closefrom(firstfd):
    """Close all file descriptors from `firstfd` on.
    """
    try:
        # Look in proc for all open filedescriptors
        maxfd = int(os.listdir('/proc/self/fd')[-1])
    except (OSError, IndexError):
        # fallback to the hardlimit to max filedescriptors.
        maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]

    os.closerange(firstfd, maxfd) 

def _run_child(self, cmd):
        if isinstance(cmd, basestring):
            cmd = ['/bin/sh', '-c', cmd]
        os.closerange(3, MAXFD)
        try:
            os.execvp(cmd[0], cmd)
        finally:
            os._exit(1) 

def _run_child(self, cmd):
        if isinstance(cmd, basestring):
            cmd = ['/bin/sh', '-c', cmd]
        os.closerange(3, MAXFD)
        try:
            os.execvp(cmd[0], cmd)
        finally:
            os._exit(1) 

def _close_fds(self, but):
            os.closerange(3, but)
            os.closerange(but + 1, MAXFD) 

def _close_fds(self, but):
            if hasattr(os, 'closerange'):
                os.closerange(3, but)
                os.closerange(but + 1, MAXFD)
            else:
                for i in xrange(3, MAXFD):
                    if i == but:
                        continue
                    try:
                        os.close(i)
                    except:
                        pass 

def exit():
    """
    Causes python to exit without garbage-collecting any objects, and thus avoids
    calling object destructor methods. This is a sledgehammer workaround for 
    a variety of bugs in PyQt and Pyside that cause crashes on exit.
    
    This function does the following in an attempt to 'safely' terminate
    the process:
    
    * Invoke atexit callbacks
    * Close all open file handles
    * os._exit()
    
    Note: there is some potential for causing damage with this function if you
    are using objects that _require_ their destructors to be called (for example,
    to properly terminate log files, disconnect from devices, etc). Situations
    like this are probably quite rare, but use at your own risk.
    """
    
    ## first disable our own cleanup function; won't be needing it.
    setConfigOptions(exitCleanup=False)
    
    ## invoke atexit callbacks
    atexit._run_exitfuncs()
    
    ## close file handles
    if sys.platform == 'darwin':
        for fd in range(3, 4096):
            if fd not in [7]:  # trying to close 7 produces an illegal instruction on the Mac.
                os.close(fd)
    else:
        os.closerange(3, 4096) ## just guessing on the maximum descriptor count..

    os._exit(0)
    


## Convenience functions for command-line use 

def test_closerange(self):
        if hasattr(os, "closerange"):
            fd = int(test_support.make_bad_fd())  # need to take an int for Jython, given this test
            # Make sure none of the descriptors we are about to close are
            # currently valid (issue 6542).
            for i in range(10):
                try: os.fstat(fd+i)
                except OSError:
                    pass
                else:
                    break
            if i < 2:
                raise unittest.SkipTest(
                    "Unable to acquire a range of invalid file descriptors")
            self.assertEqual(os.closerange(fd, fd + i-1), None) 

def _close_fds(self, but):
            os.closerange(3, but)
            os.closerange(but + 1, MAXFD) 

def close_all_fds_except(fds):
    fds = list(fds) + [-1, MAXFD]
    fds.sort()
    assert fds[-1] == MAXFD, 'fd too large'
    for i in range(len(fds) - 1):
        os.closerange(fds[i]+1, fds[i+1])
#
# Close sys.stdin and replace stdin with os.devnull
# 

def test_closerange(self):
        fd = support.make_bad_fd()
        # Make sure none of the descriptors we are about to close are
        # currently valid (issue 6542).
        for i in range(10):
            try: os.fstat(fd+i)
            except OSError:
                pass
            else:
                break
        if i < 2:
            raise unittest.SkipTest(
                "Unable to acquire a range of invalid file descriptors")
        self.assertEqual(os.closerange(fd, fd + i-1), None) 

def test_urandom_fd_reopened(self):
        # Issue #21207: urandom() should detect its fd to /dev/urandom
        # changed to something else, and reopen it.
        with open(support.TESTFN, 'wb') as f:
            f.write(b"x" * 256)
        self.addCleanup(os.unlink, support.TESTFN)
        code = """if 1:
            import os
            import sys
            import test.support
            os.urandom(4)
            with test.support.SuppressCrashReport():
                for fd in range(3, 256):
                    try:
                        os.close(fd)
                    except OSError:
                        pass
                    else:
                        # Found the urandom fd (XXX hopefully)
                        break
                os.closerange(3, 256)
            with open({TESTFN!r}, 'rb') as f:
                os.dup2(f.fileno(), fd)
                sys.stdout.buffer.write(os.urandom(4))
                sys.stdout.buffer.write(os.urandom(4))
            """.format(TESTFN=support.TESTFN)
        rc, out, err = assert_python_ok('-Sc', code)
        self.assertEqual(len(out), 8)
        self.assertNotEqual(out[0:4], out[4:8])
        rc, out2, err2 = assert_python_ok('-Sc', code)
        self.assertEqual(len(out2), 8)
        self.assertNotEqual(out2, out) 

def test_urandom_fd_closed(self):
        # Issue #21207: urandom() should reopen its fd to /dev/urandom if
        # closed.
        code = """if 1:
            import os
            import sys
            import test.support
            os.urandom(4)
            with test.support.SuppressCrashReport():
                os.closerange(3, 256)
            sys.stdout.buffer.write(os.urandom(4))
            """
        rc, out, err = assert_python_ok('-Sc', code) 

def _close_fds(self, keep):
            # `keep` is a set of fds, so we
            # use os.closerange from 3 to min(keep)
            # and then from max(keep + 1) to MAXFD and
            # loop through filling in the gaps.
            # Under new python versions, we need to explicitly set
            # passed fds to be inheritable or they will go away on exec
            if hasattr(os, 'set_inheritable'):
                set_inheritable = os.set_inheritable
            else:
                set_inheritable = lambda i, v: True
            if hasattr(os, 'closerange'):
                keep = sorted(keep)
                min_keep = min(keep)
                max_keep = max(keep)
                os.closerange(3, min_keep)
                os.closerange(max_keep + 1, MAXFD)
                for i in xrange(min_keep, max_keep):
                    if i in keep:
                        set_inheritable(i, True)
                        continue

                    try:
                        os.close(i)
                    except:
                        pass
            else:
                for i in xrange(3, MAXFD):
                    if i in keep:
                        set_inheritable(i, True)
                        continue
                    try:
                        os.close(i)
                    except:
                        pass 

def _close_fds(self, but):
            if hasattr(os, 'closerange'):
                os.closerange(3, but)
                os.closerange(but + 1, MAXFD)
            else:
                for i in xrange(3, MAXFD):
                    if i == but:
                        continue
                    try:
                        os.close(i)
                    except:
                        pass 

def _run_child(self, cmd):
        if isinstance(cmd, basestring):
            cmd = ['/bin/sh', '-c', cmd]
        os.closerange(3, MAXFD)
        try:
            os.execvp(cmd[0], cmd)
        finally:
            os._exit(1) 

def _run_child(self, cmd):
        if isinstance(cmd, basestring):
            cmd = ['/bin/sh', '-c', cmd]
        os.closerange(3, MAXFD)
        try:
            os.execvp(cmd[0], cmd)
        finally:
            os._exit(1)