>From d31226fd4867c4af8a77e2a90771c9c927f02f88 Mon Sep 17 00:00:00 2001
From: Brian Cully <bjc@kublai.com>
Date: Wed, 26 Oct 2022 21:10:21 -0400
Subject: [PATCH v1] Add the "doas" alias to eshell.

  * lisp/eshell/em-tramp.el (eshell/doas): new function.
---
 lisp/eshell/em-tramp.el | 47 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 43 insertions(+), 4 deletions(-)

diff --git a/lisp/eshell/em-tramp.el b/lisp/eshell/em-tramp.el
index aebbc36e71..7969a88a2b 100644
--- a/lisp/eshell/em-tramp.el
+++ b/lisp/eshell/em-tramp.el
@@ -40,9 +40,10 @@
  (defgroup eshell-tramp nil
    "This module defines commands that use TRAMP in a way that is
   not transparent to the user.  So far, this includes only the
-  built-in su and sudo commands, which are not compatible with
-  the full, external su and sudo commands, and require the user
-  to understand how to use the TRAMP sudo method."
+  built-in su, sudo and doas commands, which are not compatible
+  with the full, external su, sudo, and doas commands, and
+  require the user to understand how to use the TRAMP sudo
+  method."
    :tag "TRAMP Eshell features"
    :group 'eshell-module))
 
@@ -52,7 +53,7 @@ eshell-tramp-initialize
     (add-hook 'pcomplete-try-first-hook
 	      'eshell-complete-host-reference nil t))
   (setq-local eshell-complex-commands
-              (append '("su" "sudo")
+              (append '("su" "sudo" "doas")
                       eshell-complex-commands)))
 
 (autoload 'eshell-parse-command "esh-cmd")
@@ -127,6 +128,44 @@ eshell/sudo
 
 (put 'eshell/sudo 'eshell-no-numeric-conversions t)
 
+(defun eshell--doas-directory (directory &optional user)
+  "Return DIRECTORY wrapped with a doas method for USER."
+  (let ((user (or user "root"))
+        (dir (file-local-name (expand-file-name directory)))
+        (prefix (file-remote-p directory))
+        (host (or (file-remote-p directory 'host)
+                 tramp-default-host))
+        (method (file-remote-p directory 'method))
+        (ruser (file-remote-p directory 'user)))
+    (if (and prefix (or (not (string-equal method "doas"))
+                     (not (string-equal ruser user))))
+        (format "%s|doas:%s@%s:%s"
+                (substring prefix 0 -1) user host dir)
+      (format "/doas:%s@%s:%s" user host dir))))
+
+(defun eshell/doas (&rest args)
+  "Call Tramp’s doas method with ARGS.
+
+Uses the system doas through Tramp's doas method."
+  (eshell-eval-using-options
+   "doas" args
+   '((?h "help" nil nil "show this usage screen")
+     (?u "user" t user "execute a command as another USER")
+     (?s "shell" nil shell "start a shell instead of executing COMMAND")
+     :show-usage
+     :parse-leading-options-only
+     :usage "[(-u | --user) USER] -s | COMMAND
+Execute a COMMAND as the superuser or another USER.")
+   (let ((dir (eshell--doas-directory default-directory user)))
+     (if shell
+         (throw 'eshell-replace-command
+                (eshell-parse-command "cd" (list dir)))
+       (throw 'eshell-external
+              (let ((default-directory dir))
+                (eshell-named-command (car args) (cdr args))))))))
+
+(put 'eshell/doas 'eshell-no-numeric-conversions t)
+
 (provide 'em-tramp)
 
 ;; Local Variables:
-- 
2.38.0