From: jari <jari.aalto@cante.net>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 10257@debbugs.gnu.org
Subject: bug#10257: 23.3.1 Cygwin: network drives - file is write protected (false positive)
Date: Tue, 13 Dec 2011 18:26:28 +0200 [thread overview]
Message-ID: <20111213162628.GB22678@picasso.cante.net> (raw)
In-Reply-To: <E1RaTZh-0006H7-3R@fencepost.gnu.org>
On 2011-12-13 09:43, Eli Zaretskii wrote:
| > | So why don't you ask on the Cygwin list whether access() and
| > | euidaccess() can be taught to give the "right" answer for files on
| > | such drives. Or maybe the question is simply whether Cygwin can be
| > | taught to determine the correct UID.
| >
| > Sure, but because The network drive is not part of Windows Domain, I'm
| > afraid Cygwin has any means to determine what the correct UID or GID
| > would be are as they have no correspondence on the Windows side.
|
| ??? As long as the network drive is mounted using Windows APIs (which
| must be the case), the NT security features should be fully supported
| for it. That includes the user and group IDs of every file. So why
| does Cygwin's `stat' return 4294967295 (which AFAIU is a fancy way of
| saying -1) for UID and GID of these files?
Response from Cygwin list:
> $ ls -la /cygdrive/z/tmp/test-epackage.el
> -rwxr--r-- 1 ???????? ???????? 437 Dec 9 20:02 /cygdrive/z/tmp/test-epackage.el
It's not a bug.
If you use winbind and the user accounts are correctly mapped to
Windows accounts, then you would see the Cygwin UIDs/GIDs
correspoding to the SID of the AD user account.
If you don't do that, there's only an invisible mapping from the
Windows SID to the Unix uid/gid. The actual UNIX account has not
the same mapping back to the Windows SID. Instead, the SID
returned from Samba to Windows is a fake SID S-1-22-1-UnixUID or
S-1-22-2-UnixGID. (..)
The rest goes into details for setting 1:1 UID, GID mapping.
Still,
- The mapped drive can be written to without any extra 1:1 GUID,UID
configuration.
- Under Cygwin, should Emacs rely on unreliable[*] UID, GID?
- Is there need for this extra prompt? The protective
nature turned into nightmare.
Much better would be to give control back to the user:
(setq write-file-interactive-confirmation-flag nil)
This doesn't affect Emacs's ability to signal an error on write
failure.
Jari
[*] Which depend on specific environment and settings user has. The
1:1 setting gets interesting for N servers that may have different
UID, GID settings for the same user names; as they may not all be part
of the same domain.
next prev parent reply other threads:[~2011-12-13 16:26 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-09 18:23 bug#10257: 23.3.1 Cygwin: network drives - file is write protected (false positive) Jari Aalto
2011-12-09 20:33 ` Ken Brown
2011-12-10 9:58 ` jaalto
2011-12-13 12:18 ` Ken Brown
2011-12-13 14:00 ` jari
2011-12-13 14:43 ` Eli Zaretskii
2011-12-13 15:12 ` Ken Brown
2011-12-13 19:27 ` Stefan Monnier
2011-12-13 20:16 ` Ken Brown
2011-12-14 2:54 ` Stefan Monnier
2011-12-14 3:27 ` Ken Brown
2011-12-14 8:01 ` Jari Aalto
2011-12-14 8:35 ` Eli Zaretskii
2011-12-14 12:24 ` Ken Brown
2011-12-14 12:55 ` Ken Brown
2011-12-14 13:10 ` Eli Zaretskii
2011-12-14 14:19 ` Ken Brown
2011-12-14 14:47 ` jari
2011-12-14 17:30 ` Eli Zaretskii
2011-12-14 17:57 ` Ken Brown
2011-12-15 2:43 ` Ken Brown
2011-12-15 2:53 ` Ken Brown
2011-12-15 3:19 ` Ken Brown
2011-12-15 4:04 ` Eli Zaretskii
2011-12-15 14:42 ` Ken Brown
2011-12-16 19:37 ` Ken Brown
2011-12-16 19:46 ` Eli Zaretskii
2011-12-16 23:15 ` Stefan Monnier
2011-12-17 17:08 ` Ken Brown
2011-12-14 14:15 ` jari
2011-12-14 14:29 ` Ken Brown
2011-12-14 14:43 ` jari
2011-12-14 17:21 ` Eli Zaretskii
2011-12-14 17:23 ` Richard Stallman
2011-12-13 16:26 ` jari [this message]
2011-12-13 16:52 ` Ken Brown
2011-12-13 17:48 ` jari
2011-12-13 17:48 ` Eli Zaretskii
2011-12-13 18:05 ` jari
2011-12-13 18:36 ` Eli Zaretskii
2011-12-15 14:44 ` Jason Rumney
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