Support Posix ACL APIs on MS-Windows.

 src/w32.c: Include sddl.h and sys/acl.h.
 (SDDL_REVISION_1): Define if not already defined.
 (g_b_init_get_security_descriptor_dacl)
 (g_b_init_convert_sd_to_sddl, g_b_init_convert_sddl_to_sd)
 (g_b_init_is_valid_security_descriptor)
 (g_b_init_set_file_security): New static flags.
 (globals_of_w32): Initialize them to zero.
 (SetFileSecurity_Name): New string constant.
 (SetFileSecurity_Proc, GetSecurityDescriptorDacl_Proc)
 (ConvertStringSecurityDescriptorToSecurityDescriptor_Proc)
 (ConvertSecurityDescriptorToStringSecurityDescriptor_Proc)
 (IsValidSecurityDescriptor_Proc): New typedefs.
 (get_file_security, get_security_descriptor_owner)
 (get_security_descriptor_group): Set errno to ENOTSUP.
 (set_file_security, get_security_descriptor_dacl)
 (is_valid_security_descriptor, convert_sd_to_sddl)
 (convert_sddl_to_sd, acl_valid, acl_to_text, acl_from_text)
 (acl_free, acl_get_file, acl_set_file): New functions.
 src/fileio.c (Fcopy_file) [WINDOWSNT]: Support copying ACLs.

 nt/inc/sys/acl.h: New file.
 nt/inc/ms-w32.h (ENOTSUP): Define if undefined.
 nt/config.nt (HAVE_POSIX_ACL): Define.

 doc/lispref/files.texi (File Attributes, Changing Files): Update to include
 MS-Windows support for ACLs.

2 files changed, 17 insertions, 4 deletions

diff --git a/doc/lispref/ChangeLog b/doc/lispref/ChangeLog
index 922147844bd..a0bbafb116f 100644
--- a/doc/lispref/ChangeLog
+++ b/doc/lispref/ChangeLog
@@ -1,3 +1,8 @@
+2012-12-17  Eli Zaretskii  <eliz@gnu.org>
+
+        * files.texi (File Attributes, Changing Files): Update to include
+        MS-Windows support for ACLs.
+
 2012-12-16  Romain Francoise  <romain@orebokech.com>
 
         * files.texi (File Attributes): Document ACL support and new
diff --git a/doc/lispref/files.texi b/doc/lispref/files.texi
index 93bee961929..5440388fe70 100644
--- a/doc/lispref/files.texi
+++ b/doc/lispref/files.texi
@@ -1357,13 +1357,14 @@ support, then the return value is @code{(nil nil nil nil)}.
   If Emacs has been compiled with @dfn{ACL} (access control list)
 support, you can use the function @code{file-acl} to retrieve a file's
 ACL entries.  The format is platform-specific; on GNU/Linux and BSD,
-Emacs uses the POSIX ACL interface.  For the function
-@code{set-file-acl}, see @ref{Changing Files}.
+Emacs uses the POSIX ACL interface, while on MS-Windows Emacs emulates
+the POSIX ACL interface with native file security APIs.  For the
+function @code{set-file-acl}, see @ref{Changing Files}.
 
 @defun file-acl filename
 This function returns the ACL entries of the file @var{filename}.
 The return value is a string containing the textual representation of
-the ACL entries, like the following:
+the ACL entries.  On Posix hosts, it looks like this:
 
 @example
 @group
@@ -1375,6 +1376,12 @@ other::r--
 @end group
 @end example
 
+@cindex security descriptor, file
+@cindex SDDL, MS-Windows
+On MS-Windows, the return value is a textual description of the file's
+@dfn{security descriptor} in @acronym{SDDL}, the @dfn{Security
+Descriptor Definition Language}.
+
 If the file does not exist or is inaccessible, or if Emacs was unable to
 determine the ACL entries, then the return value is @code{nil}.  The
 latter can happen for local files if Emacs was not compiled with ACL
@@ -1719,7 +1726,8 @@ SELinux support.
 This function sets the ACL entries of the file @var{filename} to
 @var{acl-string}.  @xref{File Attributes}, for a brief description of
 ACLs.  The @var{acl-string} argument should be a string containing the
-textual representation of the desired ACL entries.
+textual representation of the desired ACL entries in the format
+appropriate for the ACL interface being used.
 @end defun
 
 @node File Names