Python: Get Mount Point on Windows or Linux

Question

I need a function to determine if a directory is a mount point for a drive. I found this code already which works well for linux:

def getmount(path):
  path = os.path.abspath(path)
  while path != os.path.sep:
    if os.path.ismount(path):
      return path
    path = os.path.abspath(os.path.join(path, os.pardir))
  return path

But I'm not sure how I would get this to work on windows. Can I just assume the mount point is the drive letter (e.g. C:)? I believe it is possible to have a network mount on windows so I'd like to be able to detect that mount as well.

Answer 1

Windows didn't use to call them "mount points" [edit: it now does, see below!], and the two typical/traditional syntaxes you can find for them are either a drive letter, e.g. Z:, or else \\hostname (with two leading backslashes: escape carefully or use r'...' notation in Python fpr such literal strings).

edit: since NTFS 5.0 mount points are supported, but according to this post the API for them is in quite a state -- "broken and ill-documented", the post's title says. Maybe executing the microsoft-supplied mountvol.exe is the least painful way -- mountvol drive:path /L should emit the mounted volume name for the specified path, or just mountvol such list all such mounts (I have to say "should" because I can't check right now). You can execute it with subprocess.Popen and check its output.

Answer 2

Do you want to find the mount point or just determine if it is a mountpoint?

Regardless, as commented above, it is possible in WinXP to map a logical drive to a folder.

See here for details: http://www.modzone.dk/forums/showthread.php?threadid=278

I would try win32api.GetVolumeInformation

>>> import win32api
>>> win32api.GetVolumeInformation("C:\\")
    ('LABEL', 1280075370, 255, 459007, 'NTFS')
>>> win32api.GetVolumeInformation("D:\\")
    ('CD LABEL', 2137801086, 110, 524293, 'CDFS')
>>> win32api.GetVolumeInformation("C:\\TEST\\") # same as D:
    ('CD LABEL', 2137801086, 110, 524293, 'CDFS')
>>> win32api.GetVolumeInformation("\\\\servername\\share\\")
    ('LABEL', -994499922, 255, 11, 'NTFS')
>>> win32api.GetVolumeInformation("C:\\WINDOWS\\") # not a mount point
    Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    pywintypes.error: (144, 'GetVolumeInformation', 'The directory is not a subdirectory of the root directory.')

Answer 3

Here is some code to return the UNC path pointed to by a drive letter. I suppose there is a more slick way to do this, but I thought I'd contribute my small part.

import sys,os,string,re,win32file
for ch in string.uppercase:  # use all uppercase letters, one at a time
    dl = ch + ":"
    try:
        flds = win32file.QueryDosDevice(dl).split("\x00")
    except:
        continue
    if re.search('^\\\\Device\\\\LanmanRedirector\\\\',flds[0]):
        flds2 = flds[0].split(":")
    st = flds2[1]
    n = st.find("\\")
    path = st[n:] 
        print(path)