An NTFS mounter for macOS, switching disks between the internal `mount_ntfs` and the additional `ntfs-3g`.

ntfs_mounter.py

#!/usr/bin/env python3
import subprocess
import plistlib
import os


def execute_and_grab_output(args):
    proc = subprocess.Popen(args, stdout=subprocess.PIPE)
    return proc.stdout.read()


class UserCancel(Exception):
    pass


def yes_or_no(prompt, default=''):
    label = 'y/n'
    if default:
        default = default[0].lower()
        if default == 'y':
            label = 'Y/n'
        elif default == 'n':
            label = 'y/N'
        else:
            raise ValueError('Invalid default', default)
    while True:
        inp = input('{} [{}] '.format(prompt, label)).strip()
        if inp:
            inp = inp[0].lower()
        else:
            inp = default
        if inp == 'y':
            return True
        elif inp == 'n':
            return False


def select(optionlist, prompt='', default=0):
    # for users, starts from 1
    # for programmers, starts from 0
    if not optionlist:
        raise ValueError('optionlist should not be empty', optionlist)
    prompt2 = (
        'Type the number to select: '
        '[q=quit, default={}] ').format(default + 1)
    while True:
        if prompt:
            print(prompt)
        for num, text in enumerate(optionlist, 1):
            print(' {}) {}'.format(num, text))
        inp = input(prompt2).strip()
        if inp == 'q':
            raise UserCancel
        if inp == '':
            return default
        try:
            inp = int(inp) - 1
            item = optionlist[inp]
            return inp
        except:
            print('Invalid selection!')


def get_disk_list():
    plist = execute_and_grab_output(['diskutil', 'list', '-plist'])
    return plistlib.loads(plist)


def get_device_detail(label):
    plist = execute_and_grab_output(['diskutil', 'info', '-plist', label])
    return plistlib.loads(plist)


def get_ntfs_volumes():
    disks = get_disk_list()['AllDisks']
    ret = []
    for label in disks:
        detail = get_device_detail(label)
        if detail.get('FilesystemType') == 'ntfs':
            ret.append(detail)
    return ret


def repr_ntfs_volume(data):
    ret = '{} => {} ({}GB, {})'.format(
        data['DeviceNode'],
        data['MountPoint'],
        round(data['VolumeSize'] / 1000**3, 2),
        'Writable' if data['WritableVolume'] else 'ReadOnly'
    )
    return ret


def remount(mounter, devicenode, mountpoint):
    ret = subprocess.call(['sudo', 'diskutil', 'umount', devicenode])
    if ret:
        raise OSError('umount failed', devicenode, ret)
    if not os.path.exists(mountpoint):
        ret = subprocess.call(['sudo', 'mkdir', mountpoint])
        if ret:
            raise OSError('mkdir failed', mountpoint, ret)
    ret = subprocess.call(['sudo', mounter, devicenode, mountpoint])
    if ret:
        raise OSError('mount failed', mounter, devicenode, mountpoint, ret)


def main():
    try:
        # select volume
        volumes = get_ntfs_volumes()
        if not volumes:
            print('No NTFS volumes available!')
            return
        num = select(
            [repr_ntfs_volume(i) for i in volumes],
            'Select a volume to change:'
        )
        vol = volumes[num]
        devicenode = vol['DeviceNode']
        mountpoint = vol['MountPoint']
        # select mounter
        mounter_options = ['mount_ntfs', 'ntfs-3g']
        num = select(
            mounter_options, 
            'Select a mounter to use:',
            0 if vol['WritableVolume'] else 1
        )
        mounter = mounter_options[num]
        # remount
        print('=>', mounter, devicenode, mountpoint)
        ret = yes_or_no('Confirm to go?', 'y')
        if not ret:
            raise UserCancel
        remount(mounter, devicenode, mountpoint)
        new_detail = get_device_detail(vol['DeviceIdentifier'])
        print('Succeed!', repr_ntfs_volume(new_detail))
        ret = yes_or_no('Open Finder for you?', 'y')
        if ret:
            subprocess.call(['open', mountpoint])
    except UserCancel:
        print('Canceled.')


if __name__ == '__main__':
    main()