Commit fa74b241 authored by Chong Yidong's avatar Chong Yidong
Browse files

Document SELinux support functions in Lisp manual.

* doc/lispref/backups.texi (Making Backups): Return value of backup-buffer is
changed.

* doc/lispref/files.texi (File Attributes): Document file-selinux-context.
(Changing Files): Link to it.
(Changing Files): Document set-file-selinux-context.

* fileio.c (Ffile_selinux_context, Fset_file_selinux_context):
Doc fix.
parent a3fcfa99
2012-02-25 Chong Yidong <cyd@gnu.org>
* files.texi (File Attributes): Document file-selinux-context.
(Changing Files): Link to it.
(Changing Files): Document set-file-selinux-context.
* backups.texi (Making Backups): Return value of backup-buffer is
changed.
* searching.texi (Regexp Backslash): Add index entry (Bug#10869).
2012-02-24 Glenn Morris <rgm@gnu.org>
......
......@@ -57,12 +57,13 @@ buffer, if appropriate. It is called by @code{save-buffer} before
saving the buffer the first time.
If a backup was made by renaming, the return value is a cons cell of
the form (@var{modes} . @var{backupname}), where @var{modes} are the
mode bits of the original file, as returned by @code{file-modes}
(@pxref{File Attributes,, Other Information about Files}), and
@var{backupname} is the name of the backup. In all other cases, that
is, if a backup was made by copying or if no backup was made, this
function returns @code{nil}.
the form (@var{modes} @var{context} @var{backupname}), where
@var{modes} are the mode bits of the original file, as returned by
@code{file-modes} (@pxref{File Attributes,, Other Information about
Files}), @var{context} is a list describing the original file's
SELinux context (@pxref{File Attributes}), and @var{backupname} is the
name of the backup. In all other cases, that is, if a backup was made
by copying or if no backup was made, this function returns @code{nil}.
@end defun
@defvar buffer-backed-up
......
......@@ -1129,6 +1129,18 @@ both others and group, and that the sticky bit is set.
@xref{Changing Files}, for functions that change file permissions,
such as @code{set-file-modes}.
@cindex MS-DOS and file modes
@cindex file modes and MS-DOS
@strong{MS-DOS note:} On MS-DOS, there is no such thing as an
``executable'' file mode bit. So @code{file-modes} considers a file
executable if its name ends in one of the standard executable
extensions, such as @file{.com}, @file{.bat}, @file{.exe}, and some
others. Files that begin with the Unix-standard @samp{#!} signature,
such as shell and Perl scripts, are also considered executable.
Directories are also reported as executable, for compatibility with
Unix. These conventions are also followed by @code{file-attributes},
below.
@end defun
If the @var{filename} argument to the next two functions is a
......@@ -1304,16 +1316,26 @@ is on the file-system device whose number is 1014478468.
@end table
@end defun
@cindex MS-DOS and file modes
@cindex file modes and MS-DOS
On MS-DOS, there is no such thing as an ``executable'' file mode bit.
So Emacs considers a file executable if its name ends in one of the
standard executable extensions, such as @file{.com}, @file{.bat},
@file{.exe}, and some others. Files that begin with the Unix-standard
@samp{#!} signature, such as shell and Perl scripts, are also considered
as executable files. This is reflected in the values returned by
@code{file-modes} and @code{file-attributes}. Directories are also
reported with executable bit set, for compatibility with Unix.
@cindex SELinux context
SELinux is a Linux kernel feature which provides more sophisticated
file access controls than ordinary ``Unix-style'' file permissions.
If Emacs has been compiled with SELinux support on a system with
SELinux enabled, you can use the function @code{file-selinux-context}
to retrieve a file's SELinux security context. For the function
@code{set-file-selinux-context}, see @ref{Changing Files}.
@defun file-selinux-context filename
This function returns the SELinux security context of the file
@var{filename}. This return value is a list of the form
@code{(@var{user} @var{role} @var{type} @var{range})}, whose elements
are the context's user, role, type, and range respectively, as Lisp
strings. See the SELinux documentation for details about what these
actually mean.
If the file does not exist or is inaccessible, or if the system does
not support SELinux, or if Emacs was not compiled with SELinux
support, then the return value is @code{(nil nil nil nil)}.
@end defun
@node Locating Files
@subsection How to Locate Files in Standard Places
......@@ -1528,15 +1550,9 @@ non-@code{nil}, we attempt to copy the user and group ownership of the
file. This works only on some operating systems, and only if you have
the correct permissions to do so.
@cindex SELinux
If the optional argument @var{preserve-selinux} is non-@code{nil}, we
attempt to copy the SELinux@footnote{@samp{Security-Enhanced Linux}
is a kernel feature that allows for finer access controls to be set on
files, and a system security policy to define who can access what.
The functions @code{file-selinux-context} and @code{set-file-selinux-context}
get and set, respectively, the SELinux properties of a file.}
context of the file. For this to work, Emacs must have been built
with libselinux support.
If the optional argument @var{preserve-selinux} is non-@code{nil}, and
Emacs has been compiled with SELinux support, this function attempts
to copy the file's SELinux context (@pxref{File Attributes}).
@end deffn
@deffn Command make-symbolic-link filename newname &optional ok-if-exists
......@@ -1667,6 +1683,16 @@ time and must be in the format returned by @code{current-time}
(@pxref{Time of Day}).
@end defun
@defun set-file-selinux-context filename context
This function sets the SELinux security context of the file
@var{filename} to @var{context}. @xref{File Attributes}, for a brief
description of SELinux contexts. The @var{context} argument should be
a list @code{(@var{user} @var{role} @var{type} @var{range})}, like the
return value of @code{file-selinux-context}. The function does
nothing if SELinux is disabled, or if Emacs was compiled without
SELinux support.
@end defun
@node File Names
@section File Names
@cindex file names
......
2012-02-25 Chong Yidong <cyd@gnu.org>
* fileio.c (Ffile_selinux_context, Fset_file_selinux_context):
Doc fix.
* xselect.c (Fx_selection_exists_p): Doc fix.
(x_clipboard_manager_save_all): Print an informative message
before saving to clipboard manager.
......
......@@ -2798,9 +2798,13 @@ See `file-symlink-p' to distinguish symlinks. */)
DEFUN ("file-selinux-context", Ffile_selinux_context,
Sfile_selinux_context, 1, 1, 0,
doc: /* Return SELinux context of file named FILENAME,
as a list ("user", "role", "type", "range"). Return (nil, nil, nil, nil)
if file does not exist, is not accessible, or SELinux is disabled */)
doc: /* Return SELinux context of file named FILENAME.
The return value is a list (USER ROLE TYPE RANGE), where the list
elements are strings naming the user, role, type, and range of the
file's SELinux security context.
Return (nil nil nil nil) if the file is nonexistent or inaccessible,
or if SELinux is disabled, or if Emacs lacks SELinux support. */)
(Lisp_Object filename)
{
Lisp_Object absname;
......@@ -2853,9 +2857,12 @@ if file does not exist, is not accessible, or SELinux is disabled */)
DEFUN ("set-file-selinux-context", Fset_file_selinux_context,
Sset_file_selinux_context, 2, 2, 0,
doc: /* Set SELinux context of file named FILENAME to CONTEXT
as a list ("user", "role", "type", "range"). Has no effect if SELinux
is disabled. */)
doc: /* Set SELinux context of file named FILENAME to CONTEXT.
CONTEXT should be a list (USER ROLE TYPE RANGE), where the list
elements are strings naming the components of a SELinux context.
This function does nothing if SELinux is disabled, or if Emacs was not
compiled with SELinux support. */)
(Lisp_Object filename, Lisp_Object context)
{
Lisp_Object absname;
......
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