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## Functions for identifying and following symlinks in Windows |
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## from user `eryksun` http://stackoverflow.com/a/27979160 |
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## 16 Jan 2015 |
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## See http://stackoverflow.com/a/15259028 for more information |
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from ctypes import * |
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from ctypes.wintypes import * |
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kernel32 = WinDLL('kernel32') |
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LPDWORD = POINTER(DWORD) |
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UCHAR = c_ubyte |
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GetFileAttributesW = kernel32.GetFileAttributesW |
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GetFileAttributesW.restype = DWORD |
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GetFileAttributesW.argtypes = (LPCWSTR,) #lpFileName In |
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INVALID_FILE_ATTRIBUTES = 0xFFFFFFFF |
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FILE_ATTRIBUTE_REPARSE_POINT = 0x00400 |
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CreateFileW = kernel32.CreateFileW |
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CreateFileW.restype = HANDLE |
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CreateFileW.argtypes = (LPCWSTR, #lpFileName In |
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DWORD, #dwDesiredAccess In |
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DWORD, #dwShareMode In |
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LPVOID, #lpSecurityAttributes In_opt |
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DWORD, #dwCreationDisposition In |
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DWORD, #dwFlagsAndAttributes In |
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HANDLE) #hTemplateFile In_opt |
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CloseHandle = kernel32.CloseHandle |
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CloseHandle.restype = BOOL |
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CloseHandle.argtypes = (HANDLE,) #hObject In |
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INVALID_HANDLE_VALUE = HANDLE(-1).value |
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OPEN_EXISTING = 3 |
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FILE_FLAG_BACKUP_SEMANTICS = 0x02000000 |
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FILE_FLAG_OPEN_REPARSE_POINT = 0x00200000 |
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DeviceIoControl = kernel32.DeviceIoControl |
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DeviceIoControl.restype = BOOL |
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DeviceIoControl.argtypes = (HANDLE, #hDevice In |
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DWORD, #dwIoControlCode In |
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LPVOID, #lpInBuffer In_opt |
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DWORD, #nInBufferSize In |
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LPVOID, #lpOutBuffer Out_opt |
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DWORD, #nOutBufferSize In |
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LPDWORD, #lpBytesReturned Out_opt |
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LPVOID) #lpOverlapped Inout_opt |
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FSCTL_GET_REPARSE_POINT = 0x000900A8 |
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IO_REPARSE_TAG_MOUNT_POINT = 0xA0000003 |
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IO_REPARSE_TAG_SYMLINK = 0xA000000C |
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MAXIMUM_REPARSE_DATA_BUFFER_SIZE = 0x4000 |
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class GENERIC_REPARSE_BUFFER(Structure): |
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_fields_ = (('DataBuffer', UCHAR * 1),) |
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class SYMBOLIC_LINK_REPARSE_BUFFER(Structure): |
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_fields_ = (('SubstituteNameOffset', USHORT), |
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('SubstituteNameLength', USHORT), |
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('PrintNameOffset', USHORT), |
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('PrintNameLength', USHORT), |
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('Flags', ULONG), |
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('PathBuffer', WCHAR * 1)) |
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@property |
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def PrintName(self): |
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arrayt = WCHAR * (self.PrintNameLength // 2) |
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offset = type(self).PathBuffer.offset + self.PrintNameOffset |
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return arrayt.from_address(addressof(self) + offset).value |
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class MOUNT_POINT_REPARSE_BUFFER(Structure): |
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_fields_ = (('SubstituteNameOffset', USHORT), |
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('SubstituteNameLength', USHORT), |
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('PrintNameOffset', USHORT), |
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('PrintNameLength', USHORT), |
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('PathBuffer', WCHAR * 1)) |
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@property |
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def PrintName(self): |
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arrayt = WCHAR * (self.PrintNameLength // 2) |
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offset = type(self).PathBuffer.offset + self.PrintNameOffset |
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return arrayt.from_address(addressof(self) + offset).value |
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class REPARSE_DATA_BUFFER(Structure): |
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class REPARSE_BUFFER(Union): |
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_fields_ = (('SymbolicLinkReparseBuffer', |
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SYMBOLIC_LINK_REPARSE_BUFFER), |
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('MountPointReparseBuffer', |
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MOUNT_POINT_REPARSE_BUFFER), |
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('GenericReparseBuffer', |
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GENERIC_REPARSE_BUFFER)) |
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_fields_ = (('ReparseTag', ULONG), |
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('ReparseDataLength', USHORT), |
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('Reserved', USHORT), |
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('ReparseBuffer', REPARSE_BUFFER)) |
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_anonymous_ = ('ReparseBuffer',) |
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def islink(path): |
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result = GetFileAttributesW(path) |
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if result == INVALID_FILE_ATTRIBUTES: |
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raise WinError() |
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return bool(result & FILE_ATTRIBUTE_REPARSE_POINT) |
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def readlink(path): |
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reparse_point_handle = CreateFileW(path, |
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0, |
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0, |
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None, |
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OPEN_EXISTING, |
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FILE_FLAG_OPEN_REPARSE_POINT | |
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FILE_FLAG_BACKUP_SEMANTICS, |
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None) |
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if reparse_point_handle == INVALID_HANDLE_VALUE: |
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raise WinError() |
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target_buffer = c_buffer(MAXIMUM_REPARSE_DATA_BUFFER_SIZE) |
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n_bytes_returned = DWORD() |
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io_result = DeviceIoControl(reparse_point_handle, |
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FSCTL_GET_REPARSE_POINT, |
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None, 0, |
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target_buffer, len(target_buffer), |
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byref(n_bytes_returned), |
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None) |
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CloseHandle(reparse_point_handle) |
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if not io_result: |
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raise WinError() |
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rdb = REPARSE_DATA_BUFFER.from_buffer(target_buffer) |
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if rdb.ReparseTag == IO_REPARSE_TAG_SYMLINK: |
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return rdb.SymbolicLinkReparseBuffer.PrintName |
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elif rdb.ReparseTag == IO_REPARSE_TAG_MOUNT_POINT: |
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return rdb.MountPointReparseBuffer.PrintName |
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raise ValueError("not a link") |
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audreyr /
cookiecutter
