[Python-bugs-list] [ python-Bugs-755617 ] os module: Need a better description of "mode"

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Bugs item #755617, was opened at 2003-06-16 19:13
Message generated for change (Comment added) made by logistix
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Category: Documentation
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Matthew Shomphe (mshomphe)
Assigned to: Nobody/Anonymous (nobody)
Summary: os module: Need a better description of "mode"

Initial Comment:
The page <http://www.python.
org/doc/current/lib/os-file-dir.html> says the following 
about the function os.chmod:

chmod(path, mode) 
Change the mode of path to the numeric mode. 
Availability: Unix, Windows. 

The "mode" values are unclear.  It turns out that the 
UNIX file permission set (e.g., 0666 for read/writeable) 
works with the Windows set (where 0666 translates to  
33206).

Is it possible to describe the file permissions in more 
detail in the documentation at this point?

Attached is an email thread discussing this 
documentation issue.

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Comment By: logistix (logistix)
Date: 2003-06-16 21:51

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Realistically, you should NEVER intentionally use chmod to set 
file permissions on Windows.  The FAT filesystem has no 
permissions, and NTFS has ACLs which are much too complex 
to map to a chmod style call.  MS only has chmod support so 
they can claim some level of posix compliance.

I'm not saying you should drop the ability to call os.chmod on 
windows, but perhaps the docs should say that its not the 
recommended way of doing things.  Unfortunately, there's not 
a recommended way of setting security that'll work on all 
Windows platforms either (although I'd start with os.popen
("cacls ...")  Even win32security requires some serious 
programming just to get started with manipulating ACLs.

Typical security looks something like this:

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\Documents and Settings\grant>xcacls "\Program files"
C:\Program Files BUILTIN\Users:R
                 BUILTIN\Users:(OI)(CI)(IO)(special access:)
                                           GENERIC_READ
                                           GENERIC_EXECUTE

                 BUILTIN\Power Users:C
                 BUILTIN\Power Users:(OI)(CI)(IO)C
                 BUILTIN\Administrators:F
                 BUILTIN\Administrators:(OI)(CI)(IO)F
                 NT AUTHORITY\SYSTEM:F
                 NT AUTHORITY\SYSTEM:(OI)(CI)(IO)F
                 BUILTIN\Administrators:F
                 CREATOR OWNER:(OI)(CI)(IO)F


C:\Documents and Settings\grant>

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Comment By: Matthew Shomphe (mshomphe)
Date: 2003-06-16 21:05

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Here's my first pass at some additional documentation.  My 
HTML skills are not up to par, but I've tried :)  I've attached 
the document separately.

m@

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Comment By: Neal Norwitz (nnorwitz)
Date: 2003-06-16 20:06

Message:
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Could you try to produce a patch to improve the
documentation?  Or perhaps suggest better wording?

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