bug#9817: 24.0.90; tar-mode: wrong display of suid and sgid bits

[Ulrich Mueller]

In the display of file modes in tar-mode's listing, the suid and sgid
bits are interchanged.

The following session illustrates the problem:

$ touch foo bar
$ chmod u+s foo
$ chmod g+s bar
$ ls -fl foo bar
-rwSr--r-- 1 ulm users 0 Oct 20 23:22 foo
-rw-r-Sr-- 1 ulm users 0 Oct 20 23:22 bar
$ tar cf foo.tar foo bar
$ tar tvf foo.tar
-rwSr--r-- ulm/users         0 2011-10-20 23:22 foo
-rw-r-Sr-- ulm/users         0 2011-10-20 23:22 bar
$ emacs -Q foo.tar

Now, in tar-mode's listing the two flags are interchanged:

 -rw-r-sr--     ulm/users         0 foo
 -rwsr--r--     ulm/users         0 bar

Also, they should be displayed with a capital letter S if the
corresponding executable bit is not set, and the sticky bit should
be shown, too. The patch included below fixes the problem for me.


2011-10-20  Ulrich Mueller  <ulm@gentoo.org>

        * tar-mode.el (tar-grind-file-mode): Display suid and sgid flags
        correctly.

@@ -404,13 +404,19 @@
   (string
    (if (zerop (logand 256 mode)) ?- ?r)
    (if (zerop (logand 128 mode)) ?- ?w)
-   (if (zerop (logand 1024 mode)) (if (zerop (logand  64 mode)) ?- ?x) ?s)
+   (if (zerop (logand 2048 mode))
+       (if (zerop (logand  64 mode)) ?- ?x)
+     (if (zerop (logand  64 mode)) ?S ?s))
    (if (zerop (logand  32 mode)) ?- ?r)
    (if (zerop (logand  16 mode)) ?- ?w)
-   (if (zerop (logand 2048 mode)) (if (zerop (logand   8 mode)) ?- ?x) ?s)
+   (if (zerop (logand 1024 mode))
+       (if (zerop (logand   8 mode)) ?- ?x)
+     (if (zerop (logand   8 mode)) ?S ?s))
    (if (zerop (logand   4 mode)) ?- ?r)
    (if (zerop (logand   2 mode)) ?- ?w)
-   (if (zerop (logand   1 mode)) ?- ?x)))
+   (if (zerop (logand 512 mode))
+       (if (zerop (logand   1 mode)) ?- ?x)
+     (if (zerop (logand   1 mode)) ?T ?t))))
 
 (defun tar-header-block-summarize (tar-hblock &optional mod-p)
   "Return a line similar to the output of `tar -vtf'."