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os.path.splitroot() splits "Global" and "GLOBALROOT" device paths incorrectly #103593

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os.path.splitroot() splits "Global" and "GLOBALROOT" device paths incorrectly#103593
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3.12only security fixes3.13only security fixesOS-windowstype-bugAn unexpected behavior, bug, or error

Description

@barneygale
barneygale
opened on Apr 17, 2023

Low priority issue, follow-up from #78079.

On Windows, os.path.splitroot() produces incorrect results for all of the following paths:

>>> from ntpath import splitroot
>>> splitroot('//./Global/Global/UNC')
('//./Global', '/', 'Global/UNC')
>>> splitroot('//./Global/Z:/')
('//./Global', '/', 'Z:/')
>>> splitroot('//?/Global/Z:/')
('//?/Global', '/', 'Z:/')
>>> splitroot('//./Global/UNC')
('//./Global', '/', 'UNC')
>>> splitroot('//?/Global/UNC/server/share/dir')
('//?/Global', '/', 'UNC/server/share/dir')
>>> splitroot('//?/GLOBALROOT/ContainerMappedDirectories/93AA221C-4061-460F-8C4E-A2EAC1BF3324')
('//?/GLOBALROOT', '/', 'ContainerMappedDirectories/93AA221C-4061-460F-8C4E-A2EAC1BF3324')
>>> splitroot('//?/GLOBALROOT/Device/LanManRedirector/abc/xyz')
('//?/GLOBALROOT', '/', 'Device/LanManRedirector/abc/xyz')
>>> splitroot('//?/GLOBALROOT/Device/Mup/abc/xyz')
('//?/GLOBALROOT', '/', 'Device/Mup/abc/xyz')
>>> splitroot('//?/GLOBALROOT/Device/WebDavRedirector/abc/xyz')
('//?/GLOBALROOT', '/', 'Device/WebDavRedirector/abc/xyz')
>>> splitroot('//?/GLOBALROOT/DosDevices/UNC/abc/xyz')
('//?/GLOBALROOT', '/', 'DosDevices/UNC/abc/xyz')
>>> splitroot('//?/GLOBALROOT/??/UNC/abc/xyz')
('//?/GLOBALROOT', '/', '??/UNC/abc/xyz')

Activity

  1. barneygale
    added
    type-bugAn unexpected behavior, bug, or error
    3.12only security fixes
    on Apr 17, 2023

  2. eryksun commented on Apr 17, 2023

    @eryksun
    eryksun
    on Apr 17, 2023
    Contributor

    The "Global" qualifier would be consumed as part of the "\\.\" or "\\?\" device prefix. Using "Global" ensures that only system device names are found, bypassing local device names created in the current logon session via WinAPI DefineDosDeviceW() or NTAPI NtCreateSymbolicLinkObject(). Repeated "Global" qualifiers don't have to be supported.

    "GlobalRoot" can be handled like the "UNC" device, by consuming up to two subsequent components, e.g "\\.\GlobalRoot\Device\HarddiskVolume2". An exception could be made to consume up to two more components if the path is on the multiple UNC device (MUP), e.g. "\\?\GlobalRoot\Device\Mup\server\share". Such a path might me returned by os.readlink() if the symlink is absolute (no relative flag) and directly targets "\Device\Mup" instead of "\??\UNC". Or maybe a script is manipulating NT paths from GetFinalPathNameByHandleW(), for example:

    >>> h = CreateFile('//localhost/C$/Windows/py.exe', 0, 0, None, 3, 0, None)
>>> p = GetFinalPathNameByHandle(h, VOLUME_NAME_NT)
>>> p = '\\\\?\\GlobalRoot' + p
>>> p
'\\\\?\\GlobalRoot\\Device\\Mup\\localhost\\C$\\Windows\\py.exe'
>>> h2 = CreateFile(p, 0, 0, None, 3, 0, None)
>>> GetFinalPathNameByHandle(h2, VOLUME_NAME_DOS)
'\\\\?\\UNC\\localhost\\C$\\Windows\\py.exe'
  3. eryksun
    added
    OS-windows
    3.13only security fixes
    on Apr 17, 2023
  4. serhiy-storchaka
    added this to OS issues 💻on Jul 3, 2026
  5. github-project-automation
    moved this to Todo in OS issues 💻on Jul 3, 2026
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