From: Michael Albinus <michael.albinus@gmx.de>
Date: Sun, 16 Dec 2018 14:49:07 +0000 (+0100)
Subject: Add Tramp sudoedit method
X-Git-Tag: emacs-27.0.90~3986
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=e8199e765f81968be840d8e7e3978f5974c1be9d;p=emacs.git

Add Tramp sudoedit method

* doc/misc/tramp.texi (Quick Start Guide): New section "Using sudoedit".
(External methods) <sudoedit>: Describe.

* lisp/net/tramp-adb.el (tramp-adb-file-name-handler-alist):
* lisp/net/tramp-gvfs.el (tramp-gvfs-file-name-handler-alist):
* lisp/net/tramp-rclone.el (tramp-rclone-file-name-handler-alist):
* lisp/net/tramp-sh.el (tramp-sh-file-name-handler-alist)
* lisp/net/tramp-smb.el (tramp-smb-file-name-handler-alist):
Add handler.

* lisp/net/tramp-sh.el (tramp-sh-handle-set-file-uid-gid): Rename from
`tramp-sh-handle-set-file-uid-gid'.  Handle only remote file names.

* lisp/net/tramp-sudoedit.el: New file.

* lisp/net/tramp.el (tramp-file-name-for-operation): Handle also
`tramp-set-file-uid-gid'.
(tramp-set-file-uid-gid): New defun.
(tramp-get-local-uid, tramp-get-local-gid): Cache result.

* test/lisp/net/tramp-tests.el (tramp--test-sudoedit-p): New defun.
(tramp-test20-file-modes, tramp-test22-file-times)
(tramp--test-sudoedit-p): Use it.
---

diff --git a/doc/misc/tramp.texi b/doc/misc/tramp.texi
index a4946f0b8de..c9f1e75d8e6 100644
--- a/doc/misc/tramp.texi
+++ b/doc/misc/tramp.texi
@@ -468,6 +468,19 @@ The method @option{sg} stands for ``switch group''; the changed group
 must be used here as user name.  The default host name is the same.
 
 
+@anchor{Quick Start Guide: @option{sudoedit} method}
+@section Using @command{sudoedit}
+@cindex method @option{sudoedit}
+@cindex @option{sudoedit} method
+
+The @option{sudoedit} method is similar to the @option{sudo} method.
+However, it is a different implementation: it does not keep an open
+session running in the background.  This is for security reasons; on
+the backside this method is less performant than the @option{sudo}
+method, it is restricted to the @samp{localhost} only, and it does not
+support external processes.
+
+
 @anchor{Quick Start Guide: @option{smb} method}
 @section Using @command{smbclient}
 @cindex method @option{smb}
@@ -919,6 +932,30 @@ NAS hosts.  These dumb devices have severely restricted local shells,
 such as the @command{busybox} and do not host any other encode or
 decode programs.
 
+@item @option{sudoedit}
+@cindex method @option{sudoedit}
+@cindex @option{sudoedit} method
+
+The @option{sudoedit} method allows to edit a file as a different user
+on the local host.  You could regard this as @value{tramp}'s
+implementation of the @command{sudoedit}.  Contrary to the
+@option{sudo} method, all magic file name functions are implemented by
+single @command{sudo @dots{}}  commands.  The purpose is to make
+editing such a file as secure as possible; there must be no session
+running in the Emacs background which could be attacked from inside
+Emacs.
+
+Consequently, external processes are not implemented.
+
+The host name of such remote file names must represent the local host.
+Since the default value is already proper, it is recommended not to
+use any host name in the remote file name, like
+@file{@trampfn{sudoedit,,/path/to/file}} or
+@file{@trampfn{sudoedit,user@@,/path/to/file}}.
+
+Like the @option{sudo} method, a @option{sudoedit} password expires
+after a predefined timeout.
+
 @item @option{ftp}
 @cindex method @option{ftp}
 @cindex @option{ftp} method
diff --git a/etc/NEWS b/etc/NEWS
index 0624c5690bc..c88f6ef5ca4 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -864,6 +864,12 @@ or NextCloud hosted files and directories.
 *** New connection method "rclone", which allows to access system
 storages via the 'rclone' program.  This feature is experimental.
 
++++
+*** New connection method "sudoedit", which allows to edit local files
+with different user credentials.  Contrary to the "sudo" method, no
+session is run permanently in the background.  This is for security
+reasons.
+
 +++
 *** Connection methods "obex" and "synce" are removed, because they
 are obsoleted in GVFS.
diff --git a/lisp/net/tramp-adb.el b/lisp/net/tramp-adb.el
index 7906ec9f7cf..7bf709b79a1 100644
--- a/lisp/net/tramp-adb.el
+++ b/lisp/net/tramp-adb.el
@@ -161,6 +161,7 @@ It is used for TCP/IP devices."
     (start-file-process . tramp-adb-handle-start-file-process)
     (substitute-in-file-name . tramp-handle-substitute-in-file-name)
     (temporary-file-directory . tramp-handle-temporary-file-directory)
+    (tramp-set-file-uid-gid . ignore)
     (unhandled-file-name-directory . ignore)
     (vc-registered . ignore)
     (verify-visited-file-modtime . tramp-handle-verify-visited-file-modtime)
diff --git a/lisp/net/tramp-archive.el b/lisp/net/tramp-archive.el
index cb072ac720f..02580359f73 100644
--- a/lisp/net/tramp-archive.el
+++ b/lisp/net/tramp-archive.el
@@ -273,6 +273,7 @@ It must be supported by libarchive(3).")
     (start-file-process . tramp-archive-handle-not-implemented)
     ;; `substitute-in-file-name' performed by default handler.
     (temporary-file-directory . tramp-archive-handle-temporary-file-directory)
+    ;; `tramp-set-file-uid-gid' performed by default handler.
     (unhandled-file-name-directory . ignore)
     (vc-registered . ignore)
     (verify-visited-file-modtime . tramp-handle-verify-visited-file-modtime)
diff --git a/lisp/net/tramp-cache.el b/lisp/net/tramp-cache.el
index 0a799d721d6..d13e6ee9f58 100644
--- a/lisp/net/tramp-cache.el
+++ b/lisp/net/tramp-cache.el
@@ -50,10 +50,11 @@
 ;;   definitions already sent to the remote shell, "last-cmd-time" is
 ;;   the time stamp a command has been sent to the remote process.
 ;;
-;; - The key is `nil'.  This are temporary properties related to the
+;; - The key is nil.  This are temporary properties related to the
 ;;   local machine.  Examples: "parse-passwd" and "parse-group" keep
-;;   the results of parsing "/etc/passwd" and "/etc/group", "locale"
-;;   is the used shell locale.
+;;   the results of parsing "/etc/passwd" and "/etc/group",
+;;   "{uid,gid}-{integer,string}" are the local uid and gid, and
+;;   "locale" is the used shell locale.
 
 ;; Some properties are handled special:
 ;;
diff --git a/lisp/net/tramp-gvfs.el b/lisp/net/tramp-gvfs.el
index e034f7bba56..295b288d06e 100644
--- a/lisp/net/tramp-gvfs.el
+++ b/lisp/net/tramp-gvfs.el
@@ -589,6 +589,7 @@ It has been changed in GVFS 1.14.")
     (start-file-process . ignore)
     (substitute-in-file-name . tramp-handle-substitute-in-file-name)
     (temporary-file-directory . tramp-handle-temporary-file-directory)
+    (tramp-set-file-uid-gid . ignore)
     (unhandled-file-name-directory . ignore)
     (vc-registered . ignore)
     (verify-visited-file-modtime . tramp-handle-verify-visited-file-modtime)
@@ -1843,7 +1844,7 @@ connection if a previous connection has died for some reason."
 	 (tramp-get-connection-process vec) "connected" t))))
 
   ;; In `tramp-check-cached-permissions', the connection properties
-  ;; {uig,gid}-{integer,string} are used.  We set them to proper values.
+  ;; "{uid,gid}-{integer,string}" are used.  We set them to proper values.
   (unless tramp-gvfs-get-remote-uid-gid-in-progress
     (let ((tramp-gvfs-get-remote-uid-gid-in-progress t))
       (tramp-gvfs-get-remote-uid vec 'integer)
diff --git a/lisp/net/tramp-rclone.el b/lisp/net/tramp-rclone.el
index 5ea42c07bf2..18cb971bd17 100644
--- a/lisp/net/tramp-rclone.el
+++ b/lisp/net/tramp-rclone.el
@@ -134,6 +134,7 @@
     (start-file-process . ignore)
     (substitute-in-file-name . tramp-handle-substitute-in-file-name)
     (temporary-file-directory . tramp-handle-temporary-file-directory)
+    (tramp-set-file-uid-gid . ignore)
     (unhandled-file-name-directory . ignore)
     (vc-registered . ignore)
     (verify-visited-file-modtime . tramp-handle-verify-visited-file-modtime)
@@ -575,7 +576,7 @@ connection if a previous connection has died for some reason."
 	  (tramp-cleanup-connection vec 'keep-debug 'keep-password)))))
 
   ;; In `tramp-check-cached-permissions', the connection properties
-  ;; {uig,gid}-{integer,string} are used.  We set them to proper values.
+  ;; "{uid,gid}-{integer,string}" are used.  We set them to proper values.
   (with-tramp-connection-property
       vec "uid-integer" (tramp-get-local-uid 'integer))
   (with-tramp-connection-property
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index a6e9d299a87..a3038780e6c 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -1044,6 +1044,7 @@ of command line.")
     (start-file-process . tramp-sh-handle-start-file-process)
     (substitute-in-file-name . tramp-handle-substitute-in-file-name)
     (temporary-file-directory . tramp-handle-temporary-file-directory)
+    (tramp-set-file-uid-gid . tramp-sh-handle-set-file-uid-gid)
     (unhandled-file-name-directory . ignore)
     (vc-registered . tramp-sh-handle-vc-registered)
     (verify-visited-file-modtime . tramp-sh-handle-verify-visited-file-modtime)
@@ -1516,39 +1517,26 @@ of."
 	      "")
 	    (tramp-shell-quote-argument localname)))))))
 
-(defun tramp-set-file-uid-gid (filename &optional uid gid)
-  "Set the ownership for FILENAME.
-If UID and GID are provided, these values are used; otherwise uid
-and gid of the corresponding user is taken.  Both parameters must
-be non-negative integers."
+(defun tramp-sh-handle-set-file-uid-gid (filename &optional uid gid)
+  "Like `tramp-set-file-uid-gid' for Tramp files."
   ;; Modern Unices allow chown only for root.  So we might need
   ;; another implementation, see `dired-do-chown'.  OTOH, it is mostly
   ;; working with su(do)? when it is needed, so it shall succeed in
   ;; the majority of cases.
   ;; Don't modify `last-coding-system-used' by accident.
   (let ((last-coding-system-used last-coding-system-used))
-    (if (tramp-tramp-file-p filename)
-	(with-parsed-tramp-file-name filename nil
-	  (if (and (zerop (user-uid)) (tramp-local-host-p v))
-	      ;; If we are root on the local host, we can do it directly.
-	      (tramp-set-file-uid-gid localname uid gid)
-	    (let ((uid (or (and (natnump uid) uid)
-			   (tramp-get-remote-uid v 'integer)))
-		  (gid (or (and (natnump gid) gid)
-			   (tramp-get-remote-gid v 'integer))))
-	      (tramp-send-command
-	       v (format
-		  "chown %d:%d %s" uid gid
-		  (tramp-shell-quote-argument localname))))))
-
-      ;; We handle also the local part, because there doesn't exist
-      ;; `set-file-uid-gid'.  On W32 "chown" does not work.
-      (unless (memq system-type '(ms-dos windows-nt))
-	(let ((uid (or (and (natnump uid) uid) (tramp-get-local-uid 'integer)))
-	      (gid (or (and (natnump gid) gid) (tramp-get-local-gid 'integer))))
-	  (tramp-call-process
-	   nil "chown" nil nil nil
-	   (format "%d:%d" uid gid) (shell-quote-argument filename)))))))
+    (with-parsed-tramp-file-name filename nil
+      (if (and (zerop (user-uid)) (tramp-local-host-p v))
+	  ;; If we are root on the local host, we can do it directly.
+	  (tramp-set-file-uid-gid localname uid gid)
+	(let ((uid (or (and (natnump uid) uid)
+		       (tramp-get-remote-uid v 'integer)))
+	      (gid (or (and (natnump gid) gid)
+		       (tramp-get-remote-gid v 'integer))))
+	  (tramp-send-command
+	   v (format
+	      "chown %d:%d %s" uid gid
+	      (tramp-shell-quote-argument localname))))))))
 
 (defun tramp-remote-selinux-p (vec)
   "Check, whether SELINUX is enabled on the remote host."
@@ -2114,6 +2102,7 @@ file names."
 
 	  ;; Handle `preserve-extended-attributes'.  We ignore possible
 	  ;; errors, because ACL strings could be incompatible.
+	  ;; `set-file-extended-attributes' exists since Emacs 24.4.
 	  (when attributes
 	    (ignore-errors
 	      (apply 'set-file-extended-attributes (list newname attributes))))
diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
index 5b7998ac970..fcc6f6c6ef0 100644
--- a/lisp/net/tramp-smb.el
+++ b/lisp/net/tramp-smb.el
@@ -282,6 +282,7 @@ See `tramp-actions-before-shell' for more info.")
     (start-file-process . tramp-smb-handle-start-file-process)
     (substitute-in-file-name . tramp-smb-handle-substitute-in-file-name)
     (temporary-file-directory . tramp-handle-temporary-file-directory)
+    (tramp-set-file-uid-gid . ignore)
     (unhandled-file-name-directory . ignore)
     (vc-registered . ignore)
     (verify-visited-file-modtime . tramp-handle-verify-visited-file-modtime)
diff --git a/lisp/net/tramp-sudoedit.el b/lisp/net/tramp-sudoedit.el
new file mode 100644
index 00000000000..640fa570ff4
--- /dev/null
+++ b/lisp/net/tramp-sudoedit.el
@@ -0,0 +1,880 @@
+;;; tramp-sudoedit.el --- Functions for accessing under root permissions  -*- lexical-binding:t -*-
+
+;; Copyright (C) 2018 Free Software Foundation, Inc.
+
+;; Author: Michael Albinus <michael.albinus@gmx.de>
+;; Keywords: comm, processes
+;; Package: tramp
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; The "sudoedit" Tramp method allows to edit a file as a different
+;; user on the local host.  Contrary to the "sudo" method, all magic
+;; file name functions are implemented by single "sudo ..."  commands.
+;; The purpose is to make editing such a file as secure as possible;
+;; there must be no session running in the Emacs background which
+;; could be attacked from inside Emacs.
+
+;; Consequently, external processes are not implemented.
+
+;;; Code:
+
+(require 'tramp)
+(require 'server)
+
+;;;###tramp-autoload
+(defconst tramp-sudoedit-method "sudoedit"
+  "When this method name is used, call sudoedit for editing a file.")
+
+;;;###tramp-autoload
+(add-to-list 'tramp-methods
+  `(,tramp-sudoedit-method
+    (tramp-sudo-login      (("sudo") ("-u" "%u") ("-S") ("-H")
+			    ("-p" "Password:") ("--")))))
+
+;;;###tramp-autoload
+(add-to-list 'tramp-default-user-alist '("\\`sudoedit\\'" nil "root"))
+
+;;;###tramp-autoload
+(eval-after-load 'tramp
+  '(tramp-set-completion-function
+    tramp-sudoedit-method tramp-completion-function-alist-su))
+
+(defconst tramp-sudoedit-sudo-actions
+  '((tramp-password-prompt-regexp tramp-action-password)
+    (tramp-wrong-passwd-regexp tramp-action-permission-denied)
+    (tramp-process-alive-regexp tramp-sudoedit-action-sudo))
+  "List of pattern/action pairs.
+This list is used for sudo calls.
+
+See `tramp-actions-before-shell' for more info.")
+
+;;;###tramp-autoload
+(defconst tramp-sudoedit-file-name-handler-alist
+  '((access-file . ignore)
+    (add-name-to-file . tramp-sudoedit-handle-add-name-to-file)
+    (byte-compiler-base-file-name . ignore)
+    ;; `copy-directory' performed by default handler.
+    (copy-file . tramp-sudoedit-handle-copy-file)
+    (delete-directory . tramp-sudoedit-handle-delete-directory)
+    (delete-file . tramp-sudoedit-handle-delete-file)
+    (diff-latest-backup-file . ignore)
+    ;; `directory-file-name' performed by default handler.
+    (directory-files . tramp-handle-directory-files)
+    (directory-files-and-attributes
+     . tramp-handle-directory-files-and-attributes)
+    (dired-compress-file . ignore)
+    (dired-uncache . tramp-handle-dired-uncache)
+    (exec-path . ignore)
+    (expand-file-name . tramp-sudoedit-handle-expand-file-name)
+    (file-accessible-directory-p . tramp-handle-file-accessible-directory-p)
+    (file-acl . tramp-sudoedit-handle-file-acl)
+    (file-attributes . tramp-sudoedit-handle-file-attributes)
+    (file-directory-p . tramp-handle-file-directory-p)
+    (file-equal-p . tramp-handle-file-equal-p)
+    (file-executable-p . tramp-sudoedit-handle-file-executable-p)
+    (file-exists-p . tramp-sudoedit-handle-file-exists-p)
+    (file-in-directory-p . tramp-handle-file-in-directory-p)
+    (file-local-copy . tramp-handle-file-local-copy)
+    (file-modes . tramp-handle-file-modes)
+    (file-name-all-completions
+     . tramp-sudoedit-handle-file-name-all-completions)
+    (file-name-as-directory . tramp-handle-file-name-as-directory)
+    (file-name-case-insensitive-p . tramp-handle-file-name-case-insensitive-p)
+    (file-name-completion . tramp-handle-file-name-completion)
+    (file-name-directory . tramp-handle-file-name-directory)
+    (file-name-nondirectory . tramp-handle-file-name-nondirectory)
+    ;; `file-name-sans-versions' performed by default handler.
+    (file-newer-than-file-p . tramp-handle-file-newer-than-file-p)
+    (file-notify-add-watch . ignore)
+    (file-notify-rm-watch . ignore)
+    (file-notify-valid-p . ignore)
+    (file-ownership-preserved-p . ignore)
+    (file-readable-p . tramp-sudoedit-handle-file-readable-p)
+    (file-regular-p . tramp-handle-file-regular-p)
+    (file-remote-p . tramp-handle-file-remote-p)
+    (file-selinux-context . tramp-sudoedit-handle-file-selinux-context)
+    (file-symlink-p . tramp-handle-file-symlink-p)
+    (file-system-info . tramp-sudoedit-handle-file-system-info)
+    (file-truename . tramp-sudoedit-handle-file-truename)
+    (file-writable-p . tramp-sudoedit-handle-file-writable-p)
+    (find-backup-file-name . tramp-handle-find-backup-file-name)
+    ;; `get-file-buffer' performed by default handler.
+    (insert-directory . tramp-handle-insert-directory)
+    (insert-file-contents . tramp-handle-insert-file-contents)
+    (load . tramp-handle-load)
+    (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
+    (make-directory . tramp-sudoedit-handle-make-directory)
+    (make-directory-internal . ignore)
+    (make-nearby-temp-file . tramp-handle-make-nearby-temp-file)
+    (make-symbolic-link . tramp-sudoedit-handle-make-symbolic-link)
+    (process-file . ignore)
+    (rename-file . tramp-sudoedit-handle-rename-file)
+    (set-file-acl . tramp-sudoedit-handle-set-file-acl)
+    (set-file-modes . tramp-sudoedit-handle-set-file-modes)
+    (set-file-selinux-context . tramp-sudoedit-handle-set-file-selinux-context)
+    (set-file-times . tramp-sudoedit-handle-set-file-times)
+    (set-visited-file-modtime . tramp-handle-set-visited-file-modtime)
+    (shell-command . ignore)
+    (start-file-process . ignore)
+    (substitute-in-file-name . tramp-handle-substitute-in-file-name)
+    (temporary-file-directory . tramp-handle-temporary-file-directory)
+    (tramp-set-file-uid-gid . tramp-sudoedit-handle-set-file-uid-gid)
+    (unhandled-file-name-directory . ignore)
+    (vc-registered . ignore)
+    (verify-visited-file-modtime . tramp-handle-verify-visited-file-modtime)
+    (write-region . tramp-sudoedit-handle-write-region))
+  "Alist of handler functions for Tramp SUDOEDIT method.")
+
+;; It must be a `defsubst' in order to push the whole code into
+;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
+;;;###tramp-autoload
+(defsubst tramp-sudoedit-file-name-p (filename)
+  "Check if it's a filename for SUDOEDIT."
+  (and (tramp-tramp-file-p filename)
+       (string= (tramp-file-name-method (tramp-dissect-file-name filename))
+		tramp-sudoedit-method)))
+
+;;;###tramp-autoload
+(defun tramp-sudoedit-file-name-handler (operation &rest args)
+  "Invoke the SUDOEDIT handler for OPERATION.
+First arg specifies the OPERATION, second arg is a list of arguments to
+pass to the OPERATION."
+  (let ((fn (assoc operation tramp-sudoedit-file-name-handler-alist)))
+    (if fn
+	(save-match-data (apply (cdr fn) args))
+      (tramp-run-real-handler operation args))))
+
+;;;###tramp-autoload
+(tramp-register-foreign-file-name-handler
+ 'tramp-sudoedit-file-name-p 'tramp-sudoedit-file-name-handler)
+
+
+;; File name primitives.
+
+(defun tramp-sudoedit-handle-add-name-to-file
+  (filename newname &optional ok-if-already-exists)
+  "Like `add-name-to-file' for Tramp files."
+  (unless (tramp-equal-remote filename newname)
+    (with-parsed-tramp-file-name
+	(if (tramp-tramp-file-p filename) filename newname) nil
+      (tramp-error
+       v 'file-error
+       "add-name-to-file: %s"
+       "only implemented for same method, same user, same host")))
+  (with-parsed-tramp-file-name filename v1
+    (with-parsed-tramp-file-name newname v2
+	;; Do the 'confirm if exists' thing.
+	(when (file-exists-p newname)
+	  ;; What to do?
+	  (if (or (null ok-if-already-exists) ; not allowed to exist
+		  (and (numberp ok-if-already-exists)
+		       (not (yes-or-no-p
+			     (format
+			      "File %s already exists; make it a link anyway? "
+			      v2-localname)))))
+	      (tramp-error v2 'file-already-exists newname)
+	    (delete-file newname)))
+	(tramp-flush-file-properties v2 (file-name-directory v2-localname))
+	(tramp-flush-file-properties v2 v2-localname)
+	(unless
+	    (tramp-sudoedit-send-command
+	     v1 "ln"
+	     (tramp-compat-file-name-unquote v1-localname)
+	     (tramp-compat-file-name-unquote v2-localname))
+	  (tramp-error
+	   v1 'file-error
+	   "error with add-name-to-file, see buffer `%s' for details"
+	   (buffer-name))))))
+
+(defun tramp-sudoedit-do-copy-or-rename-file
+  (op filename newname &optional ok-if-already-exists keep-date
+   preserve-uid-gid preserve-extended-attributes)
+  "Copy or rename a remote file.
+OP must be `copy' or `rename' and indicates the operation to perform.
+FILENAME specifies the file to copy or rename, NEWNAME is the name of
+the new file (for copy) or the new name of the file (for rename).
+OK-IF-ALREADY-EXISTS means don't barf if NEWNAME exists already.
+KEEP-DATE means to make sure that NEWNAME has the same timestamp
+as FILENAME.  PRESERVE-UID-GID, when non-nil, instructs to keep
+the uid and gid if both files are on the same host.
+PRESERVE-EXTENDED-ATTRIBUTES activates selinux and acl commands.
+
+This function is invoked by `tramp-sudoedit-handle-copy-file' and
+`tramp-sudoedit-handle-rename-file'.  It is an error if OP is
+neither of `copy' and `rename'.  FILENAME and NEWNAME must be
+absolute file names."
+  (unless (memq op '(copy rename))
+    (error "Unknown operation `%s', must be `copy' or `rename'" op))
+
+  (setq filename (file-truename filename))
+  (if (file-directory-p filename)
+      (progn
+	(copy-directory filename newname keep-date t)
+	(when (eq op 'rename) (delete-directory filename 'recursive)))
+
+    (let ((t1 (tramp-sudoedit-file-name-p filename))
+	  (t2 (tramp-sudoedit-file-name-p newname))
+	  (file-times (tramp-compat-file-attribute-modification-time
+		       (file-attributes filename)))
+	  (file-modes (tramp-default-file-modes filename))
+	  ;; `file-extended-attributes' exists since Emacs 24.4.
+	  (attributes (and preserve-extended-attributes
+			   (apply 'file-extended-attributes (list filename))))
+	  (sudoedit-operation
+	   (cond
+	    ((and (eq op 'copy) preserve-uid-gid) '("cp" "-f" "-p"))
+	    ((eq op 'copy) '("cp" "-f"))
+	    ((eq op 'rename) '("mv" "-f"))))
+	  (msg-operation (if (eq op 'copy) "Copying" "Renaming")))
+
+      (with-parsed-tramp-file-name (if t1 filename newname) nil
+	(when (and (not ok-if-already-exists) (file-exists-p newname))
+	  (tramp-error v 'file-already-exists newname))
+
+	(if (or (and (file-remote-p filename) (not t1))
+		(and (file-remote-p newname)  (not t2)))
+	    ;; We cannot copy or rename directly.
+	    (let ((tmpfile (tramp-compat-make-temp-file filename)))
+	      (if (eq op 'copy)
+		  (copy-file filename tmpfile t)
+		(rename-file filename tmpfile t))
+	      (rename-file tmpfile newname ok-if-already-exists))
+
+	  ;; Direct action.
+	  (with-tramp-progress-reporter
+	      v 0 (format "%s %s to %s" msg-operation filename newname)
+	    (unless (tramp-sudoedit-send-command
+		     v sudoedit-operation
+		     (tramp-compat-file-name-unquote
+		      (tramp-compat-file-local-name filename))
+		     (tramp-compat-file-name-unquote
+		      (tramp-compat-file-local-name newname)))
+	      (tramp-error
+	       v 'file-error
+	       "Error %s `%s' `%s'" msg-operation filename newname))))
+
+	;; When `newname' is local, we must change the ownership to
+	;; the local user.
+	(unless (file-remote-p newname)
+	  (tramp-set-file-uid-gid
+	   (concat (file-remote-p filename) newname)
+	   (tramp-get-local-uid 'integer)
+	   (tramp-get-local-gid 'integer)))
+
+	;; Set the time and mode. Mask possible errors.
+	(when keep-date
+	  (ignore-errors
+	    (set-file-times newname file-times)
+	    (set-file-modes newname file-modes)))
+
+	;; Handle `preserve-extended-attributes'.  We ignore possible
+	;; errors, because ACL strings could be incompatible.
+	;; `set-file-extended-attributes' exists since Emacs 24.4.
+	(when attributes
+	  (ignore-errors
+	    (apply 'set-file-extended-attributes (list newname attributes))))
+
+	(when (and t1 (eq op 'rename))
+	  (with-parsed-tramp-file-name filename v1
+	    (tramp-flush-file-properties
+	     v1 (file-name-directory v1-localname))
+	    (tramp-flush-file-properties v1 v1-localname)))
+
+	(when t2
+	  (with-parsed-tramp-file-name newname v2
+	    (tramp-flush-file-properties
+	     v2 (file-name-directory v2-localname))
+	    (tramp-flush-file-properties v2 v2-localname)
+	    (when (tramp-rclone-file-name-p newname))))))))
+
+(defun tramp-sudoedit-handle-copy-file
+  (filename newname &optional ok-if-already-exists keep-date
+   preserve-uid-gid preserve-extended-attributes)
+  "Like `copy-file' for Tramp files."
+  (setq filename (expand-file-name filename))
+  (setq newname (expand-file-name newname))
+  ;; At least one file a Tramp file?
+  (if (or (tramp-tramp-file-p filename)
+	  (tramp-tramp-file-p newname))
+      (tramp-sudoedit-do-copy-or-rename-file
+       'copy filename newname ok-if-already-exists keep-date
+       preserve-uid-gid preserve-extended-attributes)
+    (tramp-run-real-handler
+     'copy-file
+     (list filename newname ok-if-already-exists keep-date
+	   preserve-uid-gid preserve-extended-attributes))))
+
+(defun tramp-sudoedit-handle-delete-directory
+    (directory &optional recursive trash)
+  "Like `delete-directory' for Tramp files."
+  (setq directory (expand-file-name directory))
+  (with-parsed-tramp-file-name directory nil
+    (tramp-flush-file-properties v (file-name-directory localname))
+    (tramp-flush-directory-properties v localname)
+    (unless
+	(tramp-sudoedit-send-command
+	 v (or (and trash "trash")
+	       (if recursive '("rm" "-rf") "rmdir"))
+	 (tramp-compat-file-name-unquote localname))
+      (tramp-error v 'file-error "Couldn't delete %s" directory))))
+
+(defun tramp-sudoedit-handle-delete-file (filename &optional trash)
+  "Like `delete-file' for Tramp files."
+  (with-parsed-tramp-file-name filename nil
+    (tramp-flush-file-properties v (file-name-directory localname))
+    (tramp-flush-file-properties v localname)
+    (unless
+	(tramp-sudoedit-send-command
+	 v (if (and trash delete-by-moving-to-trash) "trash" "rm")
+	 (tramp-compat-file-name-unquote localname))
+      ;; Propagate the error.
+      (with-current-buffer (tramp-get-connection-buffer v)
+	(goto-char (point-min))
+	(tramp-error-with-buffer
+	 nil v 'file-error "Couldn't delete %s" filename)))))
+
+(defun tramp-sudoedit-handle-expand-file-name (name &optional dir)
+  "Like `expand-file-name' for Tramp files.
+If the localname part of the given file name starts with \"/../\" then
+the result will be a local, non-Tramp, file name."
+  ;; If DIR is not given, use `default-directory' or "/".
+  (setq dir (or dir default-directory "/"))
+  ;; Unless NAME is absolute, concat DIR and NAME.
+  (unless (file-name-absolute-p name)
+    (setq name (concat (file-name-as-directory dir) name)))
+  (with-parsed-tramp-file-name name nil
+    ;; Tilde expansion if necessary.  We cannot accept "~/", because
+    ;; under sudo "~/" is expanded to the local user home directory
+    ;; but to the root home directory.
+    (when (zerop (length localname))
+      (setq localname "~"))
+    (unless (file-name-absolute-p localname)
+      (setq localname (format "~%s/%s" user localname)))
+    (when (string-match "\\`\\(~[^/]*\\)\\(.*\\)\\'" localname)
+      (let ((uname (match-string 1 localname))
+	    (fname (match-string 2 localname)))
+	(when (string-equal uname "~")
+	  (setq uname (concat uname user)))
+	(setq localname (concat uname fname))))
+    ;; Do normal `expand-file-name' (this does "~user/", "/./" and "/../").
+    (tramp-make-tramp-file-name v (expand-file-name localname))))
+
+(defun tramp-sudoedit-remote-acl-p (vec)
+  "Check, whether ACL is enabled on the remote host."
+  (with-tramp-connection-property (tramp-get-connection-process vec) "acl-p"
+    (zerop (tramp-call-process vec "getfacl" nil nil nil "/"))))
+
+(defun tramp-sudoedit-handle-file-acl (filename)
+  "Like `file-acl' for Tramp files."
+  (with-parsed-tramp-file-name filename nil
+    (with-tramp-file-property v localname "file-acl"
+      (let ((result (and (tramp-sudoedit-remote-acl-p v)
+			 (tramp-sudoedit-send-command-string
+			  v "getfacl" "-acp"
+			  (tramp-compat-file-name-unquote localname)))))
+	;; The acl string must have a trailing \n, which is not
+	;; provided by `tramp-sudoedit-send-command-string'.  Add it.
+	(and (stringp result) (concat result "\n"))))))
+
+(defun tramp-sudoedit-handle-file-attributes (filename &optional id-format)
+  "Like `file-attributes' for Tramp files."
+  (unless id-format (setq id-format 'integer))
+  (with-parsed-tramp-file-name (expand-file-name filename) nil
+    (with-tramp-file-property
+	v localname (format "file-attributes-%s" id-format)
+      (tramp-message v 5 "file attributes: %s" localname)
+      (ignore-errors
+	(tramp-convert-file-attributes
+	 v
+	 (tramp-sudoedit-send-command-and-read
+	  v "env" "QUOTING_STYLE=locale" "stat" "-c"
+	  (format
+	   ;; Apostrophes in the stat output are masked as
+	   ;; `tramp-stat-marker', in order to make a proper shell
+	   ;; escape of them in file names.
+	   "((%s%%N%s) %%h %s %s %%X %%Y %%Z %%s %s%%A%s t %%i -1)"
+	   tramp-stat-marker tramp-stat-marker
+	   (if (eq id-format 'integer)
+	       "%u"
+	     (eval-when-compile
+	       (concat tramp-stat-marker "%U" tramp-stat-marker)))
+	   (if (eq id-format 'integer)
+	       "%g"
+	     (eval-when-compile
+	       (concat tramp-stat-marker "%G" tramp-stat-marker)))
+	   tramp-stat-marker tramp-stat-marker)
+	  (tramp-compat-file-name-unquote localname)))))))
+
+(defun tramp-sudoedit-handle-file-executable-p (filename)
+  "Like `file-executable-p' for Tramp files."
+  (with-parsed-tramp-file-name filename nil
+    (with-tramp-file-property v localname "file-executable-p"
+      (tramp-sudoedit-send-command
+       v "test" "-x" (tramp-compat-file-name-unquote localname)))))
+
+(defun tramp-sudoedit-handle-file-exists-p (filename)
+  "Like `file-exists-p' for Tramp files."
+  (with-parsed-tramp-file-name filename nil
+    (with-tramp-file-property v localname "file-exists-p"
+      (tramp-sudoedit-send-command
+       v "test" "-e" (tramp-compat-file-name-unquote localname)))))
+
+(defun tramp-sudoedit-handle-file-name-all-completions (filename directory)
+  "Like `file-name-all-completions' for Tramp files."
+  (all-completions
+   filename
+   (with-parsed-tramp-file-name (expand-file-name directory) nil
+     (with-tramp-file-property v localname "file-name-all-completions"
+       (tramp-sudoedit-send-command
+	v "ls" "-a1" "--quoting-style=literal" "--show-control-chars"
+	(if (zerop (length localname))
+	    "" (tramp-compat-file-name-unquote localname)))
+       (mapcar
+	(lambda (f)
+	  (if (file-directory-p (expand-file-name f directory))
+	      (file-name-as-directory f)
+	    f))
+	(with-current-buffer (tramp-get-connection-buffer v)
+	  (delq
+	   nil
+	   (mapcar
+	    (lambda (l) (and (not (string-match-p  "^[[:space:]]*$" l)) l))
+	    (split-string (buffer-string) "\n" 'omit)))))))))
+
+(defun tramp-sudoedit-handle-file-readable-p (filename)
+  "Like `file-readable-p' for Tramp files."
+  (with-parsed-tramp-file-name filename nil
+    (with-tramp-file-property v localname "file-readable-p"
+      (tramp-sudoedit-send-command
+       v "test" "-r" (tramp-compat-file-name-unquote localname)))))
+
+(defun tramp-sudoedit-handle-set-file-modes (filename mode)
+  "Like `set-file-modes' for Tramp files."
+  (with-parsed-tramp-file-name filename nil
+    (tramp-flush-file-properties v (file-name-directory localname))
+    (tramp-flush-file-properties v localname)
+    (unless (tramp-sudoedit-send-command
+	     v "chmod" (format "%o" mode)
+	     (tramp-compat-file-name-unquote localname))
+      (tramp-error
+       v 'file-error "Error while changing file's mode %s" filename))))
+
+(defun tramp-sudoedit-remote-selinux-p (vec)
+  "Check, whether SELINUX is enabled on the remote host."
+  (with-tramp-connection-property (tramp-get-connection-process vec) "selinux-p"
+    (zerop (tramp-call-process vec "selinuxenabled"))))
+
+(defun tramp-sudoedit-handle-file-selinux-context (filename)
+  "Like `file-selinux-context' for Tramp files."
+  (with-parsed-tramp-file-name filename nil
+    (with-tramp-file-property v localname "file-selinux-context"
+      (let ((context '(nil nil nil nil))
+	    (regexp (eval-when-compile
+		      (concat "\\([a-z0-9_]+\\):" "\\([a-z0-9_]+\\):"
+			      "\\([a-z0-9_]+\\):" "\\([a-z0-9_]+\\)"))))
+	(when (and (tramp-sudoedit-remote-selinux-p v)
+		   (tramp-sudoedit-send-command
+		    v "ls" "-d" "-Z"
+		    (tramp-compat-file-name-unquote localname)))
+	  (with-current-buffer (tramp-get-connection-buffer v)
+	    (goto-char (point-min))
+	    (when (re-search-forward regexp (point-at-eol) t)
+	      (setq context (list (match-string 1) (match-string 2)
+				  (match-string 3) (match-string 4))))))
+	;; Return the context.
+	context))))
+
+(defun tramp-sudoedit-handle-file-system-info (filename)
+  "Like `file-system-info' for Tramp files."
+  (ignore-errors
+    (with-parsed-tramp-file-name (expand-file-name filename) nil
+      (tramp-message v 5 "file system info: %s" localname)
+      (when (tramp-sudoedit-send-command
+	     v "df" "--block-size=1" "--output=size,used,avail"
+	     (tramp-compat-file-name-unquote localname)))
+      (with-current-buffer (tramp-get-connection-buffer v)
+	(goto-char (point-min))
+	(forward-line)
+	(when (looking-at
+	       (eval-when-compile
+		 (concat "[[:space:]]*\\([[:digit:]]+\\)"
+			 "[[:space:]]+\\([[:digit:]]+\\)"
+			 "[[:space:]]+\\([[:digit:]]+\\)")))
+	  (list (string-to-number (match-string 1))
+		;; The second value is the used size.  We need the
+		;; free size.
+		(- (string-to-number (match-string 1))
+		   (string-to-number (match-string 2)))
+		(string-to-number (match-string 3))))))))
+
+(defun tramp-sudoedit-handle-set-file-times (filename &optional time)
+  "Like `set-file-times' for Tramp files."
+  (with-parsed-tramp-file-name filename nil
+    (tramp-flush-file-properties v (file-name-directory localname))
+    (tramp-flush-file-properties v localname)
+    (let ((time
+	   (if (or (null time)
+		   (tramp-compat-time-equal-p time tramp-time-doesnt-exist)
+		   (tramp-compat-time-equal-p time tramp-time-dont-know))
+	       (current-time)
+	     time)))
+      (tramp-sudoedit-send-command
+       v "env" "TZ=UTC" "touch" "-t"
+       (format-time-string "%Y%m%d%H%M.%S" time t)
+       (tramp-compat-file-name-unquote localname)))))
+
+(defun tramp-sudoedit-handle-file-truename (filename)
+  "Like `file-truename' for Tramp files."
+   ;; Preserve trailing "/".
+  (funcall
+   (if (string-equal (file-name-nondirectory filename) "")
+       'file-name-as-directory 'identity)
+   (with-parsed-tramp-file-name (expand-file-name filename) nil
+     (tramp-make-tramp-file-name
+      v
+      (with-tramp-file-property v localname "file-truename"
+	(let ((quoted (tramp-compat-file-name-quoted-p localname))
+	      (localname (tramp-compat-file-name-unquote localname))
+	      result)
+	  (tramp-message v 4 "Finding true name for `%s'" filename)
+	  (setq result (tramp-sudoedit-send-command-string
+			v "readlink" "--canonicalize-missing" localname))
+	  ;; Detect cycle.
+	  (when (and (file-symlink-p filename)
+		     (string-equal result localname))
+	    (tramp-error
+	     v 'file-error
+	     "Apparent cycle of symbolic links for %s" filename))
+	  ;; If the resulting localname looks remote, we must quote it
+	  ;; for security reasons.
+	  (when (or quoted (file-remote-p result))
+	    (let (file-name-handler-alist)
+	      (setq result (tramp-compat-file-name-quote result))))
+	  (tramp-message v 4 "True name of `%s' is `%s'" localname result)
+	  result))
+      'nohop))))
+
+(defun tramp-sudoedit-handle-file-writable-p (filename)
+  "Like `file-writable-p' for Tramp files."
+  (with-parsed-tramp-file-name filename nil
+    (with-tramp-file-property v localname "file-writable-p"
+      (if (file-exists-p filename)
+	  (tramp-sudoedit-send-command
+	   v "test" "-w" (tramp-compat-file-name-unquote localname))
+	(let ((dir (file-name-directory filename)))
+	  (and (file-exists-p dir)
+	       (file-writable-p dir)))))))
+
+(defun tramp-sudoedit-handle-make-directory (dir &optional parents)
+  "Like `make-directory' for Tramp files."
+  (setq dir (expand-file-name dir))
+  (with-parsed-tramp-file-name dir nil
+    ;; When PARENTS is non-nil, DIR could be a chain of non-existent
+    ;; directories a/b/c/...  Instead of checking, we simply flush the
+    ;; whole cache.
+    (tramp-flush-directory-properties
+     v (if parents "/" (file-name-directory localname)))
+    (unless (tramp-sudoedit-send-command
+	     v (if parents '("mkdir" "-p") "mkdir")
+	     (tramp-compat-file-name-unquote localname))
+      (tramp-error v 'file-error "Couldn't make directory %s" dir))))
+
+(defun tramp-sudoedit-handle-make-symbolic-link
+    (target linkname &optional ok-if-already-exists)
+  "Like `make-symbolic-link' for Tramp files.
+If TARGET is a non-Tramp file, it is used verbatim as the target
+of the symlink.  If TARGET is a Tramp file, only the localname
+component is used as the target of the symlink."
+  (if (not (tramp-tramp-file-p (expand-file-name linkname)))
+      (tramp-run-real-handler
+       'make-symbolic-link (list target linkname ok-if-already-exists))
+
+    (with-parsed-tramp-file-name linkname nil
+      ;; If TARGET is a Tramp name, use just the localname component.
+      (when (and (tramp-tramp-file-p target)
+		 (tramp-file-name-equal-p v (tramp-dissect-file-name target)))
+	(setq target
+	      (tramp-file-name-localname
+	       (tramp-dissect-file-name (expand-file-name target)))))
+
+      ;; If TARGET is still remote, quote it.
+      (if (tramp-tramp-file-p target)
+	  (make-symbolic-link
+	   (let (file-name-handler-alist) (tramp-compat-file-name-quote target))
+	   linkname ok-if-already-exists)
+
+	;; Do the 'confirm if exists' thing.
+	(when (file-exists-p linkname)
+	  ;; What to do?
+	  (if (or (null ok-if-already-exists) ; not allowed to exist
+		  (and (numberp ok-if-already-exists)
+		       (not
+			(yes-or-no-p
+			 (format
+			  "File %s already exists; make it a link anyway? "
+			  localname)))))
+	      (tramp-error v 'file-already-exists localname)
+	    (delete-file linkname)))
+
+	(tramp-flush-file-properties v (file-name-directory localname))
+	(tramp-flush-file-properties v localname)
+        (tramp-sudoedit-send-command
+	 v "ln" "-sf"
+	 (tramp-compat-file-name-unquote target)
+	 (tramp-compat-file-name-unquote localname))))))
+
+(defun tramp-sudoedit-handle-rename-file
+  (filename newname &optional ok-if-already-exists)
+  "Like `rename-file' for Tramp files."
+  (setq filename (expand-file-name filename))
+  (setq newname (expand-file-name newname))
+  ;; At least one file a Tramp file?
+  (if (or (tramp-tramp-file-p filename)
+          (tramp-tramp-file-p newname))
+      (tramp-sudoedit-do-copy-or-rename-file
+       'rename filename newname ok-if-already-exists
+       'keep-date 'preserve-uid-gid)
+    (tramp-run-real-handler
+     'rename-file (list filename newname ok-if-already-exists))))
+
+(defun tramp-sudoedit-handle-set-file-acl (filename acl-string)
+  "Like `set-file-acl' for Tramp files."
+  (with-parsed-tramp-file-name (expand-file-name filename) nil
+    (when (and (stringp acl-string) (tramp-sudoedit-remote-acl-p v))
+      ;; Massage `acl-string'.
+      (setq acl-string
+	    (mapconcat 'identity (split-string acl-string "\n" 'omit) ","))
+      (prog1
+	  (tramp-sudoedit-send-command
+	   v "setfacl" "-m"
+	   acl-string (tramp-compat-file-name-unquote localname))
+	(tramp-flush-file-property v localname "file-acl")))))
+
+(defun tramp-sudoedit-handle-set-file-selinux-context (filename context)
+  "Like `set-file-selinux-context' for Tramp files."
+  (with-parsed-tramp-file-name filename nil
+    (when (and (consp context)
+	       (tramp-sudoedit-remote-selinux-p v))
+      (let ((user (and (stringp (nth 0 context)) (nth 0 context)))
+	    (role (and (stringp (nth 1 context)) (nth 1 context)))
+	    (type (and (stringp (nth 2 context)) (nth 2 context)))
+	    (range (and (stringp (nth 3 context)) (nth 3 context))))
+	(when (tramp-sudoedit-send-command
+	       v  "chcon"
+	       (when user (format "--user=%s" user))
+	       (when role (format "--role=%s" role))
+	       (when type (format "--type=%s" type))
+	       (when range (format "--range=%s" range))
+	       (tramp-compat-file-name-unquote localname))
+	  (if (and user role type range)
+	      (tramp-set-file-property
+	       v localname "file-selinux-context" context)
+	    (tramp-flush-file-property v localname "file-selinux-context"))
+	  t)))))
+
+(defun tramp-sudoedit-get-remote-uid (vec id-format)
+  "The uid of the remote connection VEC, in ID-FORMAT.
+ID-FORMAT valid values are `string' and `integer'."
+  (with-tramp-connection-property vec (format "uid-%s" id-format)
+    (if (equal id-format 'integer)
+	(tramp-sudoedit-send-command-and-read vec "id" "-u")
+      (tramp-sudoedit-send-command-string vec "id" "-un"))))
+
+(defun tramp-sudoedit-get-remote-gid (vec id-format)
+  "The gid of the remote connection VEC, in ID-FORMAT.
+ID-FORMAT valid values are `string' and `integer'."
+  (with-tramp-connection-property vec (format "gid-%s" id-format)
+    (if (equal id-format 'integer)
+	(tramp-sudoedit-send-command-and-read vec "id" "-g")
+      (tramp-sudoedit-send-command-string vec "id" "-gn"))))
+
+(defun tramp-sudoedit-handle-set-file-uid-gid (filename &optional uid gid)
+  "Like `tramp-set-file-uid-gid' for Tramp files."
+    (with-parsed-tramp-file-name filename nil
+      (tramp-sudoedit-send-command
+       v "chown"
+       (format "%d:%d"
+	       (or uid (tramp-sudoedit-get-remote-uid v 'integer))
+	       (or gid (tramp-sudoedit-get-remote-gid v 'integer)))
+       (tramp-compat-file-name-unquote
+	(tramp-compat-file-local-name filename)))))
+
+(defun tramp-sudoedit-handle-write-region
+  (start end filename &optional append visit lockname mustbenew)
+  "Like `write-region' for Tramp files."
+  (with-parsed-tramp-file-name filename nil
+    (let ((uid (or (tramp-compat-file-attribute-user-id
+		    (file-attributes filename 'integer))
+		   (tramp-sudoedit-get-remote-uid v 'integer)))
+	  (gid (or (tramp-compat-file-attribute-group-id
+		    (file-attributes filename 'integer))
+		   (tramp-sudoedit-get-remote-gid v 'integer)))
+	  (modes (tramp-default-file-modes filename)))
+      (prog1
+	  (tramp-handle-write-region
+	   start end filename append visit lockname mustbenew)
+
+	;; Set the ownership and modes.  This is not performed in
+	;; `tramp-handle-write-region'.
+	(unless (and (= (tramp-compat-file-attribute-user-id
+			 (file-attributes filename 'integer))
+			uid)
+                     (= (tramp-compat-file-attribute-group-id
+			 (file-attributes filename 'integer))
+			gid))
+          (tramp-set-file-uid-gid filename uid gid))
+	(set-file-modes filename modes)))))
+
+
+;; Internal functions.
+
+;; Used in `tramp-sudoedit-sudo-actions'.
+(defun tramp-sudoedit-action-sudo (proc vec)
+  "Check, whether a sudo process copy has finished."
+  ;; There might be pending output for the exit status.
+  (tramp-accept-process-output proc 0.1)
+  (when (not (process-live-p proc))
+    ;; Delete narrowed region, it would be in the way reading a Lisp form.
+    (goto-char (point-min))
+    (widen)
+    (delete-region (point-min) (point))
+    ;; Delete empty lines.
+    (goto-char (point-min))
+    (while (and (not (eobp)) (= (point) (point-at-eol)))
+      (forward-line))
+    (delete-region (point-min) (point))
+    (tramp-message vec 3 "Process has finished.")
+    (throw 'tramp-action 'ok)))
+
+(defun tramp-sudoedit-maybe-open-connection (vec)
+  "Maybe open a connection VEC.
+Does not do anything if a connection is already open, but re-opens the
+connection if a previous connection has died for some reason."
+  ;; We need a process bound to the connection buffer.  Therefore, we
+  ;; create a dummy process.  Maybe there is a better solution?
+  (unless (tramp-get-connection-process vec)
+    (let ((p (make-network-process
+	      :name (tramp-buffer-name vec)
+	      :buffer (tramp-get-connection-buffer vec)
+	      :server t :host 'local :service t :noquery t)))
+      (process-put p 'vector vec)
+      (set-process-query-on-exit-flag p nil)
+
+      ;; Set connection-local variables.
+      (tramp-set-connection-local-variables vec))
+
+    ;; In `tramp-check-cached-permissions', the connection properties
+    ;; "{uid,gid}-{integer,string}" are used.  We set them to proper values.
+    (tramp-sudoedit-get-remote-uid vec 'integer)
+    (tramp-sudoedit-get-remote-gid vec 'integer)
+    (tramp-sudoedit-get-remote-uid vec 'string)
+    (tramp-sudoedit-get-remote-gid vec 'string)))
+
+(defun tramp-sudoedit-send-command (vec &rest args)
+  "Send commands ARGS to connection VEC.
+If an element of ARGS is a list, it will be flattened.  If an
+element of ARGS is nil, it will be deleted.
+Erases temporary buffer before sending the command.  Returns nil
+in case of error, t otherwise."
+  (tramp-sudoedit-maybe-open-connection vec)
+  (with-current-buffer (tramp-get-connection-buffer vec)
+    (erase-buffer)
+    (let* ((login (tramp-get-method-parameter vec 'tramp-sudo-login))
+	   (host (or (tramp-file-name-host vec) ""))
+	   (user (or (tramp-file-name-user vec) ""))
+	   (spec (format-spec-make ?h host ?u user))
+	   (args (append
+		  (tramp-compat-flatten-list
+		   (mapcar
+		    (lambda (x)
+		      (setq x (mapcar (lambda (y) (format-spec y spec)) x))
+		      (unless (member "" x) x))
+		    login))
+		  (tramp-compat-flatten-list (delq nil args))))
+	   (delete-exited-processes t)
+	   (process-connection-type tramp-process-connection-type)
+	   (p (apply 'start-process
+		     (tramp-get-connection-name vec) (current-buffer) args))
+	   ;; We suppress the messages `Waiting for prompts from remote shell'.
+	   (tramp-verbose (if (= tramp-verbose 3) 2 tramp-verbose))
+	   ;; We do not want to save the password.
+	   auth-source-save-behavior)
+      (tramp-message vec 6 "%s" (mapconcat 'identity (process-command p) " "))
+      ;; Avoid process status message in output buffer.
+      (set-process-sentinel p 'ignore)
+      (process-put p 'vector vec)
+      (process-put p 'adjust-window-size-function 'ignore)
+      (set-process-query-on-exit-flag p nil)
+      (tramp-process-actions p vec nil tramp-sudoedit-sudo-actions)
+      (tramp-message vec 6 "%s\n%s" (process-exit-status p) (buffer-string))
+      (prog1
+	  (zerop (process-exit-status p))
+	(delete-process p)))))
+
+(defun tramp-sudoedit-send-command-and-read (vec &rest args)
+  "Run command ARGS and return the output, which must be a Lisp expression.
+In case there is no valid Lisp expression, it raises an error."
+  (when (apply 'tramp-sudoedit-send-command vec args)
+    (with-current-buffer (tramp-get-connection-buffer vec)
+      ;; Replace stat marker.
+      (goto-char (point-min))
+      (when (search-forward tramp-stat-marker nil t)
+	(goto-char (point-min))
+	(while (search-forward "\"" nil t)
+	  (replace-match "\\\"" nil 'literal))
+	(goto-char (point-min))
+	(while (search-forward tramp-stat-marker nil t)
+	  (replace-match "\"")))
+      ;; Read the expression.
+      (tramp-message vec 6 "\n%s" (buffer-string))
+      (goto-char (point-min))
+      (condition-case nil
+	  (prog1 (read (current-buffer))
+	    ;; Error handling.
+	    (when (re-search-forward "\\S-" (point-at-eol) t)
+	      (error nil)))
+	(error (tramp-error
+		vec 'file-error
+		"`%s' does not return a valid Lisp expression: `%s'"
+		(car args) (buffer-string)))))))
+
+(defun tramp-sudoedit-send-command-string (vec &rest args)
+  "Run command ARGS and return the output as astring."
+  (when (apply 'tramp-sudoedit-send-command vec args)
+    (with-current-buffer (tramp-get-connection-buffer vec)
+      (tramp-message vec 6 "\n%s" (buffer-string))
+      (goto-char (point-max))
+      ;(delete-blank-lines)
+      (while (looking-back "[ \t\n]+" nil 'greedy)
+	(delete-region (match-beginning 0) (point)))
+      (when (> (point-max) (point-min))
+	(substring-no-properties (buffer-string))))))
+
+(add-hook 'tramp-unload-hook
+	  (lambda ()
+	    (unload-feature 'tramp-sudoedit 'force)))
+
+(provide 'tramp-sudoedit)
+
+;;; TODO:
+
+;; * Fix *-selinux functions.  Likely, this is due to wrong file
+;;   ownership after `write-region' and/or `copy-file'.
+
+;;; tramp-sudoedit.el ends here
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index a44abfdcbbd..a1514f85a32 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -2234,7 +2234,9 @@ ARGS are the arguments OPERATION has been called with."
 	      ;; Emacs 26+ only.
 	      file-name-case-insensitive-p
 	      ;; Emacs 27+ only.
-	      file-system-info))
+	      file-system-info
+	      ;; Tramp internal magic file name function.
+	      tramp-set-file-uid-gid))
     (if (file-name-absolute-p (nth 0 args))
 	(nth 0 args)
       default-directory))
@@ -4329,24 +4331,49 @@ This is used internally by `tramp-file-mode-from-int'."
 		(and suid (upcase suid-text)) ; suid, !execute
 		(and x "x") "-"))))	; !suid
 
+;; This is a Tramp internal function.  A general `set-file-uid-gid'
+;; outside Tramp is not needed, I believe.
+(defun tramp-set-file-uid-gid (filename &optional uid gid)
+  "Set the ownership for FILENAME.
+If UID and GID are provided, these values are used; otherwise uid
+and gid of the corresponding remote or local user is taken,
+depending whether FILENAME is remote or local.  Both parameters
+must be non-negative integers.
+If FILENAME is remote, a file name handler is called."
+  (let ((handler (find-file-name-handler filename 'tramp-set-file-uid-gid)))
+    (if handler
+	(funcall handler 'tramp-set-file-uid-gid filename uid gid)
+      ;; On W32 "chown" does not work.
+      (unless (memq system-type '(ms-dos windows-nt))
+	(let ((uid (or (and (natnump uid) uid) (tramp-get-local-uid 'integer)))
+	      (gid (or (and (natnump gid) gid) (tramp-get-local-gid 'integer))))
+	  (tramp-call-process
+	   nil "chown" nil nil nil
+	   (format "%d:%d" uid gid) (shell-quote-argument filename)))))))
+
 ;;;###tramp-autoload
 (defun tramp-get-local-uid (id-format)
   "The uid of the local user, in ID-FORMAT.
 ID-FORMAT valid values are `string' and `integer'."
-  (if (equal id-format 'integer) (user-uid) (user-login-name)))
+  ;; We use key nil for local connection properties.
+  (with-tramp-connection-property nil (format "uid-%s" id-format)
+    (if (equal id-format 'integer) (user-uid) (user-login-name))))
 
 ;;;###tramp-autoload
 (defun tramp-get-local-gid (id-format)
   "The gid of the local user, in ID-FORMAT.
 ID-FORMAT valid values are `string' and `integer'."
-  (cond
-   ;; `group-gid' has been introduced with Emacs 24.4.
-   ((and (fboundp 'group-gid) (equal id-format 'integer))
-    (tramp-compat-funcall 'group-gid))
-   ;; `group-name' has been introduced with Emacs 27.1.
-   ((and (fboundp 'group-name) (equal id-format 'string))
-    (tramp-compat-funcall 'group-name (tramp-compat-funcall 'group-gid)))
-   ((tramp-compat-file-attribute-group-id (file-attributes "~/" id-format)))))
+  ;; We use key nil for local connection properties.
+  (with-tramp-connection-property nil (format "gid-%s" id-format)
+    (cond
+     ;; `group-gid' has been introduced with Emacs 24.4.
+     ((and (fboundp 'group-gid) (equal id-format 'integer))
+      (tramp-compat-funcall 'group-gid))
+     ;; `group-name' has been introduced with Emacs 27.1.
+     ((and (fboundp 'group-name) (equal id-format 'string))
+      (tramp-compat-funcall 'group-name (tramp-compat-funcall 'group-gid)))
+     ((tramp-compat-file-attribute-group-id
+       (file-attributes "~/" id-format))))))
 
 (defun tramp-get-local-locale (&optional vec)
   "Determine locale, supporting UTF8 if possible.
diff --git a/test/lisp/net/tramp-tests.el b/test/lisp/net/tramp-tests.el
index d68804a1c4e..056b6ce8360 100644
--- a/test/lisp/net/tramp-tests.el
+++ b/test/lisp/net/tramp-tests.el
@@ -3009,7 +3009,7 @@ This tests also `file-readable-p', `file-regular-p' and
   "Check `file-modes'.
 This tests also `file-executable-p', `file-writable-p' and `set-file-modes'."
   (skip-unless (tramp--test-enabled))
-  (skip-unless (tramp--test-sh-p))
+  (skip-unless (or (tramp--test-sh-p) (tramp--test-sudoedit-p)))
 
   (dolist (quoted (if (tramp--test-expensive-test) '(nil t) '(nil)))
     (let ((tmp-name (tramp--test-make-temp-name nil quoted)))
@@ -3309,7 +3309,8 @@ This tests also `make-symbolic-link', `file-truename' and `add-name-to-file'."
 (ert-deftest tramp-test22-file-times ()
   "Check `set-file-times' and `file-newer-than-file-p'."
   (skip-unless (tramp--test-enabled))
-  (skip-unless (or (tramp--test-adb-p) (tramp--test-sh-p)))
+  (skip-unless
+   (or (tramp--test-adb-p) (tramp--test-sh-p) (tramp--test-sudoedit-p)))
 
   (dolist (quoted (if (tramp--test-expensive-test) '(nil t) '(nil)))
     (let ((tmp-name1 (tramp--test-make-temp-name nil quoted))
@@ -4567,6 +4568,10 @@ This does not support special file names."
    (tramp-find-foreign-file-name-handler tramp-test-temporary-file-directory)
    'tramp-sh-file-name-handler))
 
+(defun tramp--test-sudoedit-p ()
+  "Check, whether the sudoedit method is used."
+  (tramp-sudoedit-file-name-p tramp-test-temporary-file-directory))
+
 (defun tramp--test-windows-nt ()
   "Check, whether the locale host runs MS Windows."
   (eq system-type 'windows-nt))
@@ -4761,6 +4766,7 @@ This requires restrictions of file name syntax."
 	 (list
 	  (if (or (tramp--test-gvfs-p)
 		  (tramp--test-rclone-p)
+		  (tramp--test-sudoedit-p)
 		  (tramp--test-windows-nt-or-smb-p))
 	      "foo bar baz"
 	    (if (or (tramp--test-adb-p)