master b43c31d2f50: New Tramp method "run0"

[Michael Albinus]

branch: master
commit b43c31d2f50dc71680dfd62412ce9b9afb6c65a4
Author: Michael Albinus <michael.albinus@gmx.de>
Commit: Michael Albinus <michael.albinus@gmx.de>

    New Tramp method "run0"
    
    * doc/misc/tramp.texi (Quick Start Guide, Inline methods)
    (Password handling, Predefined connection information)
    (Ad-hoc multi-hops): Add "run0".
    (Remote processes): Mention tramp-use-connection-share.
    
    * etc/NEWS: New Tramp method "run0".
    
    * lisp/net/tramp.el (tramp-completion-dissect-file-name):
    * lisp/net/tramp-cmds.el (tramp-list-remote-buffers):
    * lisp/net/tramp-smb.el (tramp-smb-handle-insert-directory):
    Use `tramp-compat-keep-seq'.
    
    * lisp/net/tramp-cmds.el (tramp-file-name-with-method): Add "run0".
    
    * lisp/net/tramp-sh.el (tramp-enable-run0-method): New defun.
    (tramp-sh-handle-expand-file-name): Add "run0".
    (tramp-maybe-open-connection): Simplify setting timeout.
---
 doc/misc/tramp.texi    | 59 +++++++++++++++++++++++++++++++++-----------------
 etc/NEWS               |  5 +++++
 lisp/net/tramp-cmds.el | 11 +++++-----
 lisp/net/tramp-sh.el   | 29 ++++++++++++++++++++-----
 lisp/net/tramp-smb.el  |  6 ++---
 lisp/net/tramp.el      | 28 +++++++++++-------------
 6 files changed, 87 insertions(+), 51 deletions(-)

diff --git a/doc/misc/tramp.texi b/doc/misc/tramp.texi
index 2b0a982e7f9..6c36429fb79 100644
--- a/doc/misc/tramp.texi
+++ b/doc/misc/tramp.texi
@@ -489,14 +489,16 @@ an @command{ssh} server:
 @file{@trampfn{plink,user@@host,/path/to/file}}.
 
 
-@anchor{Quick Start Guide su, sudo, doas, androidsu and sg methods}
-@section Using @option{su}, @option{sudo}, @option{doas}, @option{androidsu} 
and @option{sg}
+@anchor{Quick Start Guide su, sudo, doas, run0, androidsu and sg methods}
+@section Using @option{su}, @option{sudo}, @option{doas}, @option{run0}, 
@option{androidsu} and @option{sg}
 @cindex method @option{su}
 @cindex @option{su} method
 @cindex method @option{sudo}
 @cindex @option{sudo} method
 @cindex method @option{doas}
 @cindex @option{doas} method
+@cindex method @option{run0}
+@cindex @option{run0} method
 @cindex method @option{androidsu}
 @cindex @option{androidsu} method
 @cindex method @option{sg}
@@ -504,9 +506,11 @@ an @command{ssh} server:
 
 Sometimes, it is necessary to work on your local host under different
 permissions.  For this, you can use the @option{su} or @option{sudo}
-connection method.  On OpenBSD systems, the @option{doas} connection
-method offers the same functionality.  If your local system is
-Android, use the method @option{androidsu} instead of @option{su}.
+connection method.  If your system is @code{systemd}-based, there is
+the @option{run0} connection method.  On OpenBSD systems, the
+@option{doas} connection method offers the same functionality.  If
+your local system is Android, use the method @option{androidsu}
+instead of @option{su}.
 
 These methods use @samp{root} as default user name and the return
 value of @code{(system-name)} as default host name.  Therefore, it is
@@ -516,8 +520,8 @@ The method @option{sg} stands for ``switch group''; here 
the user name
 is used as the group to change to.  The default host name is the same.
 
 
-@anchor{Quick Start Guide Combining ssh, plink, su, sudo and doas methods}
-@section Combining @option{ssh} or @option{plink} with @option{su}, 
@option{sudo} or @option{doas}
+@anchor{Quick Start Guide Combining ssh, plink, su, sudo, doas and run0 
methods}
+@section Combining @option{ssh} or @option{plink} with @option{su}, 
@option{sudo}, @option{doas} or @option{run0}
 @cindex method @option{ssh}
 @cindex @option{ssh} method
 @cindex method @option{plink}
@@ -528,13 +532,15 @@ is used as the group to change to.  The default host name 
is the same.
 @cindex @option{sudo} method
 @cindex method @option{doas}
 @cindex @option{doas} method
-
-If the @option{su}, @option{sudo} or @option{doas} option should be
-performed on another host, it can be combined with a leading
-@option{ssh} or @option{plink} option.  That means that @value{tramp}
-connects first to the other host with non-administrative credentials,
-and changes to administrative credentials on that host afterwards.  In
-a simple case, the syntax looks like
+@cindex method @option{run0}
+@cindex @option{run0} method
+
+If the @option{su}, @option{sudo}, @option{doas} or @option{run0}
+method should be performed on another host, it can be combined with a
+leading @option{ssh} or @option{plink} method.  That means that
+@value{tramp} connects first to the other host with non-administrative
+credentials, and changes to administrative credentials on that host
+afterwards.  In a simple case, the syntax looks like
 @file{@trampfn{ssh@value{postfixhop}user@@host|sudo,,/path/to/file}}.
 @xref{Ad-hoc multi-hops}.
 
@@ -882,6 +888,16 @@ This method is used on OpenBSD like the @command{sudo} 
command.  Like
 the @option{sudo} method, a @option{doas} connection is disabled after
 a predefined timeout.
 
+@item @option{run0}
+@cindex method @option{run0}
+@cindex @option{run0} method
+
+This method is used on @code{systemd}-based hosts.  Internally, it
+uses the @code{systemd-run} command.  A @option{run0} connection is
+disabled after a predefined timeout as well.
+
+This is an optional method, @ref{Optional methods}.
+
 @item @option{sg}
 @cindex method @option{sg}
 @cindex @option{sg} method
@@ -2104,8 +2120,9 @@ machine melancholia#4711 port davs login daniel%BIZARRE 
password geheim
 
 For the methods @option{doas}, @option{sudo} and @option{sudoedit} the
 password of the user requesting the connection is needed, and not the
-password of the target user.  If these connections happen on the local
-host, an entry with the local user and local host is used:
+password of the target user@footnote{On the local host, @code{run0}
+uses a graphical password agent.}.  If these connections happen on the
+local host, an entry with the local user and local host is used:
 
 @example
 machine @var{host} port sudo login @var{user} password secret
@@ -2278,8 +2295,8 @@ All @file{tramp-sh.el} based methods accept the property
 @t{"session-timeout"}.  This is the time (in seconds) after a
 connection is disabled for security reasons, and must be
 reestablished.  A value of @code{nil} disables this feature.  Most of
-the methods do not set this property except the @option{sudo} and
-@option{doas} methods, which use predefined values.
+the methods do not set this property except the @option{sudo},
+@option{doas} and @option{run0} methods, which use predefined values.
 
 @item @t{"~"}@*
 @t{"~user"}
@@ -3815,7 +3832,7 @@ The buffer must either visit a file, or a directory
 @defopt tramp-file-name-with-method
 The method @code{tramp-revert-buffer-with-sudo} shows an alternate
 buffer.  It defaults to @code{sudo}, other valid methods are
-@code{su}, @code{doas}, and @code{ksu}.
+@code{su}, @code{doas}, @code{run0}, and @code{ksu}.
 
 @lisp
 (customize-set-variable 'tramp-file-name-with-method "doas")
@@ -4056,7 +4073,9 @@ here will not work as expected.
 @vindex ForwardX11Trusted@r{, ssh option}
 An alternate approach is specify @option{ForwardX11 yes} or
 @option{ForwardX11Trusted yes} in @file{~/.ssh/config} on the local
-host.
+host.  Furthermore, set @code{tramp-use-connection-share} to
+@code{nil} (@pxref{Using ssh connection sharing}), in order to avoid
+unwanted side effects.
 
 
 @subsection Running @code{shell} on a remote host
diff --git a/etc/NEWS b/etc/NEWS
index bd68cd6d751..846bf759995 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1069,6 +1069,11 @@ This provides access to system files with elevated 
privileges granted by
 the idiosyncratic 'su' implementations and system utilities customary on
 Android.
 
++++
+*** New optional connection method "run0".
+This connection method is similar to "sudo", but it uses the
+'systemd-run' program internally.
+
 +++
 *** New connection methods "dockercp" and "podmancp".
 These are the external methods counterparts of "docker" and "podman".
diff --git a/lisp/net/tramp-cmds.el b/lisp/net/tramp-cmds.el
index f381c2e9ff0..6cd856c10e5 100644
--- a/lisp/net/tramp-cmds.el
+++ b/lisp/net/tramp-cmds.el
@@ -70,12 +70,10 @@ SYNTAX can be one of the symbols `default' (default),
 ;;;###tramp-autoload
 (defun tramp-list-remote-buffers ()
   "Return a list of all buffers with remote `default-directory'."
-  (delq
-   nil
-   (mapcar
-    (lambda (x)
-      (when (tramp-tramp-file-p (tramp-get-default-directory x)) x))
-    (buffer-list))))
+  (tramp-compat-seq-keep
+   (lambda (x)
+     (when (tramp-tramp-file-p (tramp-get-default-directory x)) x))
+   (buffer-list)))
 
 ;;; Cleanup
 
@@ -567,6 +565,7 @@ For details, see `tramp-rename-files'."
   :type '(choice (const "su")
                 (const "sudo")
                 (const "doas")
+                (const "run0")
                 (const "ksu")))
 
 (defun tramp-file-name-with-sudo (filename)
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 408e1611632..b79b55ee2cc 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -501,6 +501,24 @@ The string is used in `tramp-methods'.")
 
   (tramp-set-completion-function "nc" tramp-completion-function-alist-telnet))
 
+;;;###tramp-autoload
+(defun tramp-enable-run0-method ()
+  "Enable \"run0\" method."
+ (add-to-list 'tramp-methods
+              `("run0"
+                (tramp-login-program        "systemd-run")
+                (tramp-login-args           (("--uid" "%u") ("-t") ("%l")))
+                (tramp-remote-shell         ,tramp-default-remote-shell)
+                (tramp-remote-shell-args    ("-c"))
+                (tramp-connection-timeout   10)
+                (tramp-session-timeout      300)
+               (tramp-password-previous-hop t)))
+
+  (add-to-list 'tramp-default-user-alist
+              `(,(rx bos "run0" eos) nil ,tramp-root-id-string))
+
+  (tramp-set-completion-function "run0" tramp-completion-function-alist-su))
+
 ;;;###tramp-autoload
 (defun tramp-enable-ksu-method ()
   "Enable \"ksu\" method."
@@ -2902,7 +2920,7 @@ the result will be a local, non-Tramp, file name."
            ;; use a user name from the config file.
            (when (and (tramp-string-empty-or-nil-p uname)
                       (string-match-p
-                       (rx bos (| "su" "sudo" "doas" "ksu") eos) method))
+                       (rx bos (| "su" "sudo" "doas" "run0" "ksu") eos) 
method))
              (setq uname user))
            (when (setq hname (tramp-get-home-directory v uname))
              (setq localname (concat hname fname)))))
@@ -5377,12 +5395,11 @@ connection if a previous connection has died for some 
reason."
                          :host l-host :port l-port)))
 
                      ;; Set session timeout.
-                     (when (tramp-get-method-parameter
-                            hop 'tramp-session-timeout)
+                     (when-let ((timeout
+                                 (tramp-get-method-parameter
+                                  hop 'tramp-session-timeout)))
                        (tramp-set-connection-property
-                        p "session-timeout"
-                        (tramp-get-method-parameter
-                         hop 'tramp-session-timeout)))
+                        p "session-timeout" timeout))
 
                      ;; Replace `login-args' place holders.
                      (setq
diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
index 3616cad2fb3..a51b2b904ec 100644
--- a/lisp/net/tramp-smb.el
+++ b/lisp/net/tramp-smb.el
@@ -1068,17 +1068,15 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are 
completely ignored."
 
          ;; Filter entries.
          (setq entries
-               (delq
-                nil
                 (if (or wildcard (string-empty-p base))
                     ;; Check for matching entries.
-                    (mapcar
+                    (tramp-compat-seq-keep
                      (lambda (x)
                        (when (string-match-p (rx bol (literal base)) (nth 0 x))
                          x))
                      entries)
                   ;; We just need the only and only entry FILENAME.
-                  (list (assoc base entries)))))
+                  (list (assoc base entries))))
 
          ;; Sort entries.
          (setq entries
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index f92a7ff14d4..02a493f0a78 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -2978,17 +2978,15 @@ They are collected by 
`tramp-completion-dissect-file-name1'."
           (regexp tramp-prefix-ipv6-regexp)
           (group (? (regexp tramp-ipv6-regexp))) eol)
          1 2 3 nil)))
-    (delq
-     nil
-     (mapcar
-      (lambda (structure) (tramp-completion-dissect-file-name1 structure name))
-      (list
-       tramp-completion-file-name-structure1
-       tramp-completion-file-name-structure2
-       tramp-completion-file-name-structure3
-       tramp-completion-file-name-structure4
-       tramp-completion-file-name-structure5
-       tramp-completion-file-name-structure6)))))
+    (tramp-compat-seq-keep
+     (lambda (structure) (tramp-completion-dissect-file-name1 structure name))
+     (list
+      tramp-completion-file-name-structure1
+      tramp-completion-file-name-structure2
+      tramp-completion-file-name-structure3
+      tramp-completion-file-name-structure4
+      tramp-completion-file-name-structure5
+      tramp-completion-file-name-structure6))))
 
 (defun tramp-completion-dissect-file-name1 (structure name)
   "Return a `tramp-file-name' structure for NAME matching STRUCTURE.
@@ -4777,10 +4775,10 @@ Do not set it manually, it is used buffer-local in 
`tramp-get-lock-pid'.")
           vec "Method `%s' is not supported for multi-hops"
           (tramp-file-name-method item)))))
 
-    ;; Some methods ("su", "sg", "sudo", "doas", "ksu") do not use the
-    ;; host name in their command template.  In this case, the remote
-    ;; file name must use either a local host name (first hop), or a
-    ;; host name matching the previous hop.
+    ;; Some methods ("su", "sg", "sudo", "doas", "run0", "ksu") do not
+    ;; use the host name in their command template.  In this case, the
+    ;; remote file name must use either a local host name (first hop),
+    ;; or a host name matching the previous hop.
     (let ((previous-host (or tramp-local-host-regexp "")))
       (setq choices target-alist)
       (while (setq item (pop choices))