Font-lock suid/guid files in Dired

* lisp/dired.el (dired-font-lock-keywords): Font-lock suid/guid
permissions (bug#8186).
(dired-sguid): New face.

2 files changed, 17 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index d9d895ac816..4e62627f907 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -752,6 +752,10 @@ remapped to these, respectively.
 
 ** Dired
 
+---
+*** On systems that support it, Dired now font-locks the permissions
+of suid/guid files specially with the 'dired-set-id' face.
+
 +++
 *** New command 'dired-create-empty-file'.
 
diff --git a/lisp/dired.el b/lisp/dired.el
index 6e48d28b4cf..57c5040263f 100644
--- a/lisp/dired.el
+++ b/lisp/dired.el
@@ -431,6 +431,13 @@ Subexpression 2 must end right before the \\n.")
 (defvar dired-perm-write-face 'dired-perm-write
   "Face name used for permissions of group- and world-writable files.")
 
+(defface dired-set-idguid'
+  '((((type w32 pc)) :inherit default)  ;; These default to rw-rw-rw.
+    (t (:inherit font-lock-warning-face)))
+  "Face used to highlight permissions of suid and guid files."
+  :group 'dired-faces
+  :version "27.1")
+
 (defface dired-directory
   '((t (:inherit font-lock-function-name-face)))
   "Face used for subdirectories."
@@ -499,6 +506,12 @@ Subexpression 2 must end right before the \\n.")
    (list (concat dired-re-maybe-mark dired-re-inode-size
                  "[-d].......\\(w\\).") ; world writable
          '(1 dired-perm-write-face))
+   (list (concat dired-re-maybe-mark dired-re-inode-size
+                 "[-d]..\\(s\\)......") ; suid
+         '(1 'dired-set-id))
+   (list (concat dired-re-maybe-mark dired-re-inode-size
+                 "[-d].....\\(S\\)...") ; guid
+         '(1 'dired-set-id))
    ;;
    ;; Subdirectories.
    (list dired-re-dir