在 Python 中创建 NTFS 连接点 [英] Create NTFS junction point in Python
问题描述
有没有办法在 Python 中创建 NTFS 连接点?我知道我可以调用 junction 实用程序，但最好不要依赖外部工具.
Is there a way to create an NTFS junction point in Python? I know I can call the junction utility, but it would be better not to rely on external tools.
推荐答案
我在 类似的问题，所以我将在下面复制我的答案.自从写了那个答案后，我最终编写了一个仅使用 python(如果您可以调用使用 ctypes python-only 的模块)模块来创建、读取和检查可以在 这个文件夹.希望有所帮助.
I answered this in a similar question, so I'll copy my answer to that below. Since writing that answer, I ended up writing a python-only (if you can call a module that uses ctypes python-only) module to creating, reading, and checking junctions which can be found in this folder. Hope that helps.
此外，与使用 CreateSymbolicLinkA API 的答案不同，链接的实现应该适用于支持连接的任何 Windows 版本.CreateSymbolicLinkA 仅在 Vista+ 中支持.
Also, unlike the answer that utilizes uses the CreateSymbolicLinkA API, the linked implementation should work on any Windows version that supports junctions. CreateSymbolicLinkA is only supported in Vista+.
答案:
或者如果你想使用pywin32，你可以使用前面提到的方法，并阅读，使用:
Or if you want to use pywin32, you can use the previously stated method, and to read, use:
from win32file import *
from winioctlcon import FSCTL_GET_REPARSE_POINT
__all__ = ['islink', 'readlink']
# Win32file doesn't seem to have this attribute.
FILE_ATTRIBUTE_REPARSE_POINT = 1024
# To make things easier.
REPARSE_FOLDER = (FILE_ATTRIBUTE_DIRECTORY | FILE_ATTRIBUTE_REPARSE_POINT)
# For the parse_reparse_buffer function
SYMBOLIC_LINK = 'symbolic'
MOUNTPOINT = 'mountpoint'
GENERIC = 'generic'
def islink(fpath):
""" Windows islink implementation. """
if GetFileAttributes(fpath) & REPARSE_FOLDER:
return True
return False
def parse_reparse_buffer(original, reparse_type=SYMBOLIC_LINK):
""" Implementing the below in Python:
typedef struct _REPARSE_DATA_BUFFER {
ULONG ReparseTag;
USHORT ReparseDataLength;
USHORT Reserved;
union {
struct {
USHORT SubstituteNameOffset;
USHORT SubstituteNameLength;
USHORT PrintNameOffset;
USHORT PrintNameLength;
ULONG Flags;
WCHAR PathBuffer[1];
} SymbolicLinkReparseBuffer;
struct {
USHORT SubstituteNameOffset;
USHORT SubstituteNameLength;
USHORT PrintNameOffset;
USHORT PrintNameLength;
WCHAR PathBuffer[1];
} MountPointReparseBuffer;
struct {
UCHAR DataBuffer[1];
} GenericReparseBuffer;
} DUMMYUNIONNAME;
} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;
"""
# Size of our data types
SZULONG = 4 # sizeof(ULONG)
SZUSHORT = 2 # sizeof(USHORT)
# Our structure.
# Probably a better way to iterate a dictionary in a particular order,
# but I was in a hurry, unfortunately, so I used pkeys.
buffer = {
'tag' : SZULONG,
'data_length' : SZUSHORT,
'reserved' : SZUSHORT,
SYMBOLIC_LINK : {
'substitute_name_offset' : SZUSHORT,
'substitute_name_length' : SZUSHORT,
'print_name_offset' : SZUSHORT,
'print_name_length' : SZUSHORT,
'flags' : SZULONG,
'buffer' : u'',
'pkeys' : [
'substitute_name_offset',
'substitute_name_length',
'print_name_offset',
'print_name_length',
'flags',
]
},
MOUNTPOINT : {
'substitute_name_offset' : SZUSHORT,
'substitute_name_length' : SZUSHORT,
'print_name_offset' : SZUSHORT,
'print_name_length' : SZUSHORT,
'buffer' : u'',
'pkeys' : [
'substitute_name_offset',
'substitute_name_length',
'print_name_offset',
'print_name_length',
]
},
GENERIC : {
'pkeys' : [],
'buffer': ''
}
}
# Header stuff
buffer['tag'] = original[:SZULONG]
buffer['data_length'] = original[SZULONG:SZUSHORT]
buffer['reserved'] = original[SZULONG+SZUSHORT:SZUSHORT]
original = original[8:]
# Parsing
k = reparse_type
for c in buffer[k]['pkeys']:
if type(buffer[k][c]) == int:
sz = buffer[k][c]
bytes = original[:sz]
buffer[k][c] = 0
for b in bytes:
n = ord(b)
if n:
buffer[k][c] += n
original = original[sz:]
# Using the offset and length's grabbed, we'll set the buffer.
buffer[k]['buffer'] = original
return buffer
def readlink(fpath):
""" Windows readlink implementation. """
# This wouldn't return true if the file didn't exist, as far as I know.
if not islink(fpath):
return None
# Open the file correctly depending on the string type.
handle = CreateFileW(fpath, GENERIC_READ, 0, None, OPEN_EXISTING, FILE_FLAG_OPEN_REPARSE_POINT, 0) \
if type(fpath) == unicode else \
CreateFile(fpath, GENERIC_READ, 0, None, OPEN_EXISTING, FILE_FLAG_OPEN_REPARSE_POINT, 0)
# MAXIMUM_REPARSE_DATA_BUFFER_SIZE = 16384 = (16*1024)
buffer = DeviceIoControl(handle, FSCTL_GET_REPARSE_POINT, None, 16*1024)
# Above will return an ugly string (byte array), so we'll need to parse it.
# But first, we'll close the handle to our file so we're not locking it anymore.
CloseHandle(handle)
# Minimum possible length (assuming that the length of the target is bigger than 0)
if len(buffer) < 9:
return None
# Parse and return our result.
result = parse_reparse_buffer(buffer)
offset = result[SYMBOLIC_LINK]['substitute_name_offset']
ending = offset + result[SYMBOLIC_LINK]['substitute_name_length']
rpath = result[SYMBOLIC_LINK]['buffer'][offset:ending].replace('\x00','')
if len(rpath) > 4 and rpath[0:4] == '\\??\\':
rpath = rpath[4:]
return rpath
def realpath(fpath):
from os import path
while islink(fpath):
rpath = readlink(fpath)
if not path.isabs(rpath):
rpath = path.abspath(path.join(path.dirname(fpath), rpath))
fpath = rpath
return fpath
def example():
from os import system, unlink
system('cmd.exe /c echo Hello World > test.txt')
system('mklink test-link.txt test.txt')
print 'IsLink: %s' % islink('test-link.txt')
print 'ReadLink: %s' % readlink('test-link.txt')
print 'RealPath: %s' % realpath('test-link.txt')
unlink('test-link.txt')
unlink('test.txt')
if __name__=='__main__':
example()
根据您的需要调整 CreateFile 中的属性，但对于正常情况，它应该可以工作.随时改进它.
Adjust the attributes in the CreateFile to your needs, but for a normal situation, it should work. Feel free to improve on it.
如果您使用 MOONTPOINT 而不是 SYMBOLIC_LINK，它也应该适用于文件夹连接.
It should also work for folder junctions if you use MOUNTPOINT instead of SYMBOLIC_LINK.
你可以检查一下
sys.getwindowsversion()[0] >= 6
如果你把它放到你要发布的东西中，因为这种形式的符号链接只在 Vista+ 上支持.
if you put this into something you're releasing, since this form of symbolic link is only supported on Vista+.
这篇关于在 Python 中创建 NTFS 连接点的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
