| msg191899 - (view) |
Author: John Jefferies (John.Jefferies) |
Date: 2013-06-26 08:44 |
| If os.stat is executed on a Windows junction with Python 3.3 I see an exception: ------------ >>> import os >>> os.stat('C:\Windows\System32\config\systemprofile\SendTo') Traceback (most recent call last): File "", line 1, in FileNotFoundError: [WinError 2] The system cannot find the file specified: 'C:\\Windows\\System32\\config\\systemprofile\\SendTo' ------------ whereas with Python 3.2 it works without error: ------------ >>> import os >>> os.stat('C:\Windows\System32\config\systemprofile\SendTo') nt.stat_result(st_mode=16895, st_ino=281474977136630, st_dev=0, st_nlink=1, st_uid=0, st_gid=0, st_size=0, st_atime=1295885671, st_mtime=1295885671, st_ctime=1295885671) ------------ FTR. Some background: It's a pity that Python doesn't just treat Windows junctions as a normal soft link. But given that islink() returns False for a junction, I was able to work around that in Python 3.2 like this: ------------ if os.path.islink(fullname) or \ os.stat(fullname)[stat.ST_INO] != os.lstat(fullname)[stat.ST_INO]: # If it's not a link, it's probably a junction... ------------ Many thanks for looking. John |
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| msg191903 - (view) |
Author: Christian Heimes (christian.heimes) *  |
Date: 2013-06-26 11:29 |
| Let's have a look |
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| msg191904 - (view) |
Author: Christian Heimes (christian.heimes) * |
Date: 2013-06-26 12:38 |
| On my Windows box (Win 7) I'm getting an error with Python 3.2 and 3.3. It looks like I'm not allowed to enter the parent directory (Zugriff verweigert == Permission Denied): >>> os.stat(r'C:\Windows\System32\config') Traceback (most recent call last): File "", line 1, in WindowsError: [Error 5] Zugriff verweigert: 'C:\\Windows\\System32\\config' In order to reproduce your problem anyway I have created a directory, a junction point and a symlink (as admin): > mkdir testdir > mklink /j testjunktion testdir > mklink /d testlinkk testdir Neither os.stat() nor os.lstat() have failed with an exception. There must be something different going on on your system. By the way junction points are soft links but not symbolic links. They are implemented as a different kind of NTFS reparsing points. Python should not treat a junction point as a link but have yet another check for it. >>> os.lstat(r'c:\users\heimes\testdir') nt.stat_result(st_mode=16895, st_ino=58265320179130300, st_dev=3366304641, st_nlink=1, st_uid=0, st_gid=0, st_size=0, st_atime=1372247959, st_mtime=1372247959, st_ctime=1372247959) >>> os.lstat(r'c:\users\heimes\testjunction') nt.stat_result(st_mode=16895, st_ino=4785074604141776, st_dev=3366304641, st_nlink=1, st_uid=0, st_gid=0, st_size=0, st_atime=1372247983, st_mtime=1372247983, st_ctime=1372247983) >>> os.lstat(r'c:\users\heimes\testlink') nt.stat_result(st_mode=41471, st_ino=12384898975270541, st_dev=3366304641, st_nlink=1, st_uid=0, st_gid=0, st_size=0, st_atime=1372249830, st_mtime=1372249830, st_ctime=1372249830) PS: You should use raw strings on Windows or escape the backslashes. |
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| msg191905 - (view) |
Author: Christian Heimes (christian.heimes) * |
Date: 2013-06-26 12:55 |
| There is much confusing about junction point on the internet. Some sites like Wikipedia claim that a junction point is a kind of soft link. Other sites refer to junction points as "directory hard links". IMO "directory hard links" is wrong. Contrary to file hard links a junction point doesn't keep the target directory alive when the target is removed. |
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| msg191906 - (view) |
Author: John Jefferies (John.Jefferies) |
Date: 2013-06-26 14:13 |
| On 26/06/2013 13:38, Christian Heimes wrote: > Christian Heimes added the comment: > > On my Windows box (Win 7) I'm getting an error with Python 3.2 and 3.3. It looks like I'm not allowed to enter the parent directory (Zugriff verweigert == Permission Denied): Ah. You need to be an administrator to look at the system directories? [I'm also on Win7]. > Neither os.stat() nor os.lstat() have failed with an exception. There > must be something different going on on your system. I didn't look closely enough; only the junctions in system folders are failing for me with an exception. The junctions in my user directory are not. I do hope I haven't wasted too much of your time in not describing the problem correctly. > By the way junction points are soft links but not symbolic links. They > are implemented as a different kind of NTFS reparsing points. Python > should not treat a junction point as a link but have yet another check > for it. I realise there are differences between junctions and symlinks at the ntfs level, but the only things that seem relevant to the application are that junctions are limited to directories on a local volume. So I consider junctions to be a subset of symlinks. Regardless, any reliable indication that a directory is a junction would be useful, and the hack I've been using thus far appeared to work for all the junctions on my system. > PS: You should use raw strings on Windows or escape the backslashes. Yes, I'm ashamed, I did know that but missed it from the example. Many thanks. John |
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| msg194046 - (view) |
Author: Tim Golden (tim.golden) * |
Date: 2013-08-01 11:09 |
| I propose to close this one: using Python 3.3 on Win7 I can successfully stat NTFS Junctions. Is there any remaining issue? |
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| msg194116 - (view) |
Author: John Jefferies (John.Jefferies) |
Date: 2013-08-01 20:41 |
| On 01/08/2013 12:09, Tim Golden wrote: > Tim Golden added the comment: > > I propose to close this one: using Python 3.3 on Win7 I can successfully stat NTFS Junctions. Is there any remaining issue? > > ---------- > > _______________________________________ > Python tracker <report@bugs.python.org> > <http://bugs.python.org/issue18306> > _______________________________________ The original issue remains for me on v3.3.2. I can stat junctions in my user directory, but not in system directories. In v3.2 I can do that provided I am running with elevated privilege. If it's fixed in the next version that's great. ------------ Python 3.3.2 (v3.3.2:d047928ae3f6, May 16 2013, 00:03:43) [MSC v.1600 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> >>> import os >>> os.stat(r'C:\Windows\System32\config\systemprofile\SendTo') Traceback (most recent call last): File "", line 1, in FileNotFoundError: [WinError 2] The system cannot find the file specified: 'C:\\Windows\\System32\\config\\systemprofile\\SendTo' >>> ------------ Regards John |
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| msg201098 - (view) |
Author: Tim Golden (tim.golden) * |
Date: 2013-10-24 08:35 |
| Just revisited this to see if I could close off. One thing occurred to me which should have come up before: this situation will be aggravated by WOW64 file redirection. If I run 64-bit Python on 64-bit Windows I can successfully stat links in %windir%\system32 under 3.4 and 3.3. If I run 32-bit Python on 64-bit Windows, I get the error you describe because Windows will silently redirect the 32-bit Python process towards %windir%\SysWow64 where the junction (or, possibly, its target) does not exist. Given that I'm able to stat %windir%\system32 junctions on both versions, I'm going to close this as works-for-me. I think there's a case for a bigger-picture look at the resolution of reparse points across the stdlib but that would have to be its own issue. |
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| msg201437 - (view) |
Author: John Jefferies (John.Jefferies) |
Date: 2013-10-27 08:58 |
| Hello Tim, The fact that it works on 64-bit Python obviously reduces the priority. I will make a point of choosing the 64-bit version in the future. FWIW. I'm dubious about the problem being solely attributable to WOWs handling of junctions because my Python 3.2 (that doesn't have the problem) is also 32-bit. There must be something else, even if that something isn't going to be fixed. Thankyou for spending time on this. John On 24/10/2013 09:35, Tim Golden wrote: > Tim Golden added the comment: > > Just revisited this to see if I could close off. One thing occurred to me which should have come up before: this situation will be aggravated by WOW64 file redirection. > > If I run 64-bit Python on 64-bit Windows I can successfully stat links in %windir%\system32 under 3.4 and 3.3. If I run 32-bit Python on 64-bit Windows, I get the error you describe because Windows will silently redirect the 32-bit Python process towards %windir%\SysWow64 where the junction (or, possibly, its target) does not exist. > > Given that I'm able to stat %windir%\system32 junctions on both versions, I'm going to close this as works-for-me. I think there's a case for a bigger-picture look at the resolution of reparse points across the stdlib but that would have to be its own issue. > > ---------- > assignee: -> tim.golden > resolution: -> works for me > stage: test needed -> committed/rejected > status: open -> closed > > _______________________________________ > Python tracker <report@bugs.python.org> > <http://bugs.python.org/issue18306> > _______________________________________ |
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| msg201478 - (view) |
Author: Tim Golden (tim.golden) * |
Date: 2013-10-27 17:27 |
| If you can put together a self-contained test case which fails on 3.3/3.4 I'm quite happy to re-open this. Given the nature of the issue, you'll have to be quite precise as to Windows version, whether 32/64, whether running as Administrator, and exact Python version. Feel free to call mklink or junction to create the link so that it's very clear what's linking to what and where. |
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