Hello and cygwin quesiton
Yap on ExactGeom
yap@cs.nyu.edu
Fri Dec 5 08:00:00 GMT 2003
Igor,
OK, I will just accept the situation!
Thanks, Chee
Igor Pechtchanski wrote:
>Chee,
>
>'/bin/vi' is a Cygwin program, and uses Cygwin system calls to create and
>write files. Thus, the permissions it gives to newly-created files are
>consistent with the other Cygwin apps. 'gvim' is probably a pure Windows
>program, which uses the Windows API calls directly, so it gives new files
>the same Windows permissions as, say, notepad does. As I mentioned
>before, this is the way Windows behaves by default: the files inherit the
>ACLs of the parent directory. Cygwin actually fixes up the ACLs later to
>make them more reasonable.
>
>For example (feel free to skip the following unless you want details):
><TECHNICAL STUFF>
>======================== begin listing ========================
>$ cmd /c 'type nul > a.txt'
>$ cacls a.txt
>C:\cygwin\tmp\acltest\a.txt BUILTIN\Administrators:(special access:)
> READ_CONTROL
> SYNCHRONIZE
> FILE_GENERIC_EXECUTE
> FILE_READ_EA
> FILE_EXECUTE
> FILE_READ_ATTRIBUTES
>
> PECHTCHA\igor:F
> Everyone:(special access:)
> READ_CONTROL
> SYNCHRONIZE
> FILE_GENERIC_EXECUTE
> FILE_READ_EA
> FILE_EXECUTE
> FILE_READ_ATTRIBUTES
>
>
>$ touch b.txt
>$ cacls b.txt
>C:\cygwin\tmp\acltest\b.txt PECHTCHA\igor:(special access:)
> STANDARD_RIGHTS_ALL
> DELETE
> READ_CONTROL
> WRITE_DAC
> WRITE_OWNER
> SYNCHRONIZE
> STANDARD_RIGHTS_REQUIRED
> FILE_GENERIC_READ
> FILE_GENERIC_WRITE
> FILE_READ_DATA
> FILE_WRITE_DATA
> FILE_APPEND_DATA
> FILE_READ_EA
> FILE_WRITE_EA
> FILE_READ_ATTRIBUTES
> FILE_WRITE_ATTRIBUTES
>
> BUILTIN\Administrators:(special access:)
> READ_CONTROL
> FILE_READ_EA
> FILE_READ_ATTRIBUTES
>
> Everyone:(special access:)
> READ_CONTROL
> FILE_READ_EA
> FILE_READ_ATTRIBUTES
>
>
>$
>========================= end listing =========================
>Note that the :F (full access) contains the following permissions:
>STANDARD_RIGHTS_ALL
>DELETE
>READ_CONTROL
>WRITE_DAC
>WRITE_OWNER
>SYNCHRONIZE
>STANDARD_RIGHTS_REQUIRED
>FILE_GENERIC_READ
>FILE_GENERIC_WRITE
>FILE_GENERIC_EXECUTE
>FILE_READ_DATA
>FILE_WRITE_DATA
>FILE_APPEND_DATA
>FILE_READ_EA
>FILE_WRITE_EA
>FILE_EXECUTE
>FILE_DELETE_CHILD
>FILE_READ_ATTRIBUTES
>FILE_WRITE_ATTRIBUTES
>
>For people on this list who are interested, the relevant ACL allocation
>code is in the alloc_sd() function in winsup/cygwin/security.cc.
></TECHNICAL STUFF>
>
>In short, there's really not much you can do, other than, perhaps, turn
>off "ntsec" (by adding "nontsec" to your CYGWIN environment variable, see
><http://cygwin.com/cygwin-ug-net/using-cygwinenv.html> and
><http://cygwin.com/cygwin-ug-net/ntsec.html>) at the risk of some services
>not working, e.g., cron, sshd, etc. Or you could change the permissions
>by hand every time. Or, if all you care about is how the files are
>displayed, use the dircolors command ("man dircolors" for details).
> Igor
>
>On Fri, 5 Dec 2003, Yap on ExactGeom wrote:
>
>
>
>>Dear Igor,
>>I guest there were no improvements on the execute permission problem.
>>
>>But I just realized that "vi" under cygwin is smart enough
>>not to give execute permissions to the files it writes
>>out. It simply keep the original permissions. Why can't gvim
>>do the same?
>>
>>Best,
>>--Chee
>>
>>Igor Pechtchanski wrote:
>>
>>
>>
>>>Chee,
>>>
>>>Well, there are people on this list who are more versed in Windows
>>>permissions issues than I, and hopefully they'll intervene and either
>>>confirm or refute my answer. If I had to guess, I'd say this has to do
>>>with inheritable permissions -- if a directory has an execute permission
>>>and the flag is set that makes all files and subdirectories inherit that
>>>permission, all your files will be marked executable. You can try to use
>>>the Windows permissions dialog to uncheck the "allow objects to inherit
>>>permissions" box, and this might solve the problem. I'm not sure why you
>>>didn't have this problem on Win2k (I do), but it could be because of some
>>>unique permissions setup.
>>>
>>>Hope this helps,
>>> Igor
>>>
>>>On Wed, 1 Oct 2003, Yap on ExactGeom wrote:
>>>
>>>
>>>
>>>
>>>
>>>>Dear Igor,
>>>>Nice to hear from you, and thanks for the clarification!
>>>>
>>>>I understand your explanation of the difference between
>>>>gvim and vim. But there is still a mystery.
>>>>
>>>>In my previous installation of cygwin, no such problems
>>>>arise. The difference is that my previous system was Windows 2000
>>>>and my current one is Windows XP. Can you explain this?
>>>>
>>>>Thanks,
>>>>--Chee
>>>>
>>>>Igor Pechtchanski wrote:
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>>On Tue, 30 Sep 2003, Yap on ExactGeom wrote:
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>Dear Igor,
>>>>>>
>>>>>>How are you? I noticed that you are an active developer of cygwin.
>>>>>>I really liked this platform and our Core Library is developed
>>>>>>on this mainly. I have a question:
>>>>>>
>>>>>>In my recent (June) installation of cygwin, there was an annoying
>>>>>>bug -- many of the files that I create are automatically given
>>>>>>the execute permission. [Since my "ls" will automatically show
>>>>>>me which files are executable, this is VERY annoying.]
>>>>>>But this behavior is not universal. If I have a non-executable
>>>>>>file, and I exit it using gvim, the file will become executable.
>>>>>>But using vim, it remains non-executable. But I don't think
>>>>>>the program is with a bad installation of gvim, because this
>>>>>>phenomenon shows up in other places.
>>>>>>
>>>>>>Heard of this bug before?
>>>>>>Thanks, Chee
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>Hi, Chee,
>>>>>
>>>>>Great to hear from you.
>>>>>
>>>>>I'm redirecting this reply to the general Cygwin list, mostly to get this
>>>>>into the archives (because I know others are having this same problem).
>>>>>Also, this brings your question up before a large body of expertise --
>>>>>perhaps someone else will find something I've missed.
>>>>>
>>>>>This is not a bug, but rather an artifact of the default permissions files
>>>>>get when written by Windows programs. Gvim is a pure Windows program, in
>>>>>contrast with vim, which is a Cygwin one. Also, vim writes files
>>>>>in-place, whereas gvim creates a new copy -- hence the change in
>>>>>permissions. Unfortunately, there isn't anything you can easily do to fix
>>>>>this. I have a script (attached) that I run periodically on my system to
>>>>>fix the executable permissions. It's not foolproof, but it's better than
>>>>>nothing (and it should err on the conservative side).
>>>>> Igor
>>>>>[fixexec script snipped]
>>>>>
>>>>>
>>>>>
>>>>>
>>>
>>>
>>>
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>>
>>
>
>
>
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