tramp.el

;;; tramp.el --- Transparent Remote Access, Multiple Protocol  -*- lexical-binding:t -*-

;; Copyright (C) 1998-2021 Free Software Foundation, Inc.

;; Author: Kai Großjohann <kai.grossjohann@gmx.net>
;;         Michael Albinus <michael.albinus@gmx.de>
;; Maintainer: 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:

;; This package provides remote file editing, similar to ange-ftp.
;; The difference is that ange-ftp uses FTP to transfer files between
;; the local and the remote host, whereas tramp.el uses a combination
;; of rsh and rcp or other work-alike programs, such as ssh/scp.
;;
;; For more detailed instructions, please see the info file.
;;
;; Notes:
;; ------
;;
;; Also see the todo list at the bottom of this file.
;;
;; The current version of Tramp can be retrieved from the following URL:
;;            https://ftp.gnu.org/gnu/tramp/
;;
;; There's a mailing list for this, as well.  Its name is:
;;            tramp-devel@gnu.org

;; You can use the Web to subscribe, under the following URL:
;;            https://lists.gnu.org/mailman/listinfo/tramp-devel
;;
;; For the adventurous, the current development sources are available
;; via Git.  You can find instructions about this at the following URL:
;;            https://savannah.gnu.org/projects/tramp/
;;
;; Don't forget to put on your asbestos longjohns, first!

;;; Code:

(require 'tramp-compat)
(require 'tramp-integration)
(require 'trampver)

;; Pacify byte-compiler.
(require 'cl-lib)
(declare-function file-notify-rm-watch "filenotify")
(declare-function netrc-parse "netrc")
(defvar auto-save-file-name-transforms)

;;; User Customizable Internal Variables:

(defgroup tramp nil
  "Edit remote files with a combination of ssh, scp, etc."
  :group 'files
  :group 'comm
  :link '(custom-manual "(tramp)Top")
  :version "22.1")

(eval-and-compile ;; So it's also available in tramp-loaddefs.el!
  (defvar tramp--startup-hook nil
    "Forms to be executed at the end of tramp.el.")
  (put 'tramp--startup-hook 'tramp-suppress-trace t)

  (defmacro tramp--with-startup (&rest body)
    "Schedule BODY to be executed at the end of tramp.el."
    `(add-hook 'tramp--startup-hook (lambda () ,@body))))

(require 'tramp-loaddefs)

;; Maybe we need once a real Tramp mode, with key bindings etc.
;;;###autoload
(defcustom tramp-mode t
  "Whether Tramp is enabled.
If it is set to nil, all remote file names are used literally."
  :type 'boolean)

(defcustom tramp-verbose 3
  "Verbosity level for Tramp messages.
Any level x includes messages for all levels 1 .. x-1.  The levels are

 0  silent (no tramp messages at all)
 1  errors
 2  warnings
 3  connection to remote hosts (default level)
 4  activities
 5  internal
 6  sent and received strings
 7  file caching
 8  connection properties
 9  test commands
10  traces (huge)."
  :type 'integer)

(defcustom tramp-debug-to-file nil
  "Whether Tramp debug messages shall be saved to file.
The debug file has the same name as the debug buffer, written to
`temporary-file-directory'."
  :version "28.1"
  :type 'boolean)

(defcustom tramp-backup-directory-alist nil
  "Alist of filename patterns and backup directory names.
Each element looks like (REGEXP . DIRECTORY), with the same meaning like
in `backup-directory-alist'.  If a Tramp file is backed up, and DIRECTORY
is a local file name, the backup directory is prepended with Tramp file
name prefix \(method, user, host) of file.

  (setq tramp-backup-directory-alist backup-directory-alist)

gives the same backup policy for Tramp files on their hosts like the
policy for local files."
  :type '(repeat (cons (regexp :tag "Regexp matching filename")
		       (directory :tag "Backup directory name"))))

(defcustom tramp-auto-save-directory nil
  "Put auto-save files in this directory, if set.
The idea is to use a local directory so that auto-saving is faster.
This setting has precedence over `auto-save-file-name-transforms'."
  :type '(choice (const :tag "Use default" nil)
		 (directory :tag "Auto save directory name")))

;; Suppress `shell-file-name' for w32 systems.
(defcustom tramp-encoding-shell
  (let (shell-file-name)
    (or (tramp-compat-funcall 'w32-shell-name) "/bin/sh"))
  "Use this program for encoding and decoding commands on the local host.
This shell is used to execute the encoding and decoding command on the
local host, so if you want to use \"~\" in those commands, you should
choose a shell here which groks tilde expansion.  \"/bin/sh\" normally
does not understand tilde expansion.

For encoding and decoding, commands like the following are executed:

    /bin/sh -c COMMAND < INPUT > OUTPUT

This variable can be used to change the \"/bin/sh\" part.  See the
variable `tramp-encoding-command-switch' for the \"-c\" part.

If the shell must be forced to be interactive, see
`tramp-encoding-command-interactive'.

Note that this variable is not used for remote commands.  There are
mechanisms in tramp.el which automatically determine the right shell to
use for the remote host."
  :type '(file :must-match t))

;; Suppress `shell-file-name' for w32 systems.
(defcustom tramp-encoding-command-switch
  (let (shell-file-name)
    (if (tramp-compat-funcall 'w32-shell-dos-semantics) "/c" "-c"))
  "Use this switch together with `tramp-encoding-shell' for local commands.
See the variable `tramp-encoding-shell' for more information."
  :type 'string)

;; Suppress `shell-file-name' for w32 systems.
(defcustom tramp-encoding-command-interactive
  (let (shell-file-name)
    (unless (tramp-compat-funcall 'w32-shell-dos-semantics) "-i"))
  "Use this switch together with `tramp-encoding-shell' for interactive shells.
See the variable `tramp-encoding-shell' for more information."
  :version "24.1"
  :type '(choice (const nil) string))

;; Since Emacs 26.1, `system-name' can return `nil' at build time if
;; Emacs is compiled with "--no-build-details".  We do expect it to be
;; a string.  (Bug#44481)
(defconst tramp-system-name (or (system-name) "")
  "The system name Tramp is running locally.")

(defvar tramp-methods nil
  "Alist of methods for remote files.
This is a list of entries of the form (NAME PARAM1 PARAM2 ...).
Each NAME stands for a remote access method.  Each PARAM is a
pair of the form (KEY VALUE).  The following KEYs are defined:

  * `tramp-remote-shell'
    This specifies the shell to use on the remote host.  This
    MUST be a Bourne-like shell.  It is normally not necessary to
    set this to any value other than \"/bin/sh\": Tramp wants to
    use a shell which groks tilde expansion, but it can search
    for it.  Also note that \"/bin/sh\" exists on all Unixen,
    this might not be true for the value that you decide to use.
    You Have Been Warned.

  * `tramp-remote-shell-login'
    This specifies the arguments to let `tramp-remote-shell' run
    as a login shell.  It defaults to (\"-l\"), but some shells,
    like ksh, require another argument.  See
    `tramp-connection-properties' for a way to overwrite the
    default value.

  * `tramp-remote-shell-args'
    For implementation of `shell-command', this specifies the
    arguments to let `tramp-remote-shell' run a single command.

  * `tramp-login-program'
    This specifies the name of the program to use for logging in to the
    remote host.  This may be the name of rsh or a workalike program,
    or the name of telnet or a workalike, or the name of su or a workalike.

  * `tramp-login-args'
    This specifies a list of lists of arguments to pass to the
    above mentioned program.  You normally want to put each
    argument in an individual string, i.e.
    (\"-a\" \"-b\") rather than (\"-a -b\").

    \"%\" followed by a letter are expanded in the arguments as
    follows:

    - \"%h\" is replaced by the host name
    - \"%u\" is replaced by the user name
    - \"%p\" is replaced by the port number
    - \"%%\" can be used to obtain a literal percent character.

    If a sub-list containing \"%h\", \"%u\" or \"%p\" is
    unchanged after expansion (i.e. no host, no user or no port
    were specified), that sublist is not used.  For e.g.

    '((\"-a\" \"-b\") (\"-l\" \"%u\"))

    that means that (\"-l\" \"%u\") is used only if the user was
    specified, and it is thus effectively optional.

    Other expansions are:

    - \"%l\" is replaced by the login shell `tramp-remote-shell'
      and its parameters.
    - \"%t\" is replaced by the temporary file name produced with
      `tramp-make-tramp-temp-file'.
    - \"%k\" indicates the keep-date parameter of a program, if exists.
    - \"%c\" adds additional `tramp-ssh-controlmaster-options'
      options for the first hop.
    - \"%n\" expands to \"2>/dev/null\".

    The existence of `tramp-login-args', combined with the
    absence of `tramp-copy-args', is an indication that the
    method is capable of multi-hops.

  * `tramp-async-args'
    When an asynchronous process is started, we know already that
    the connection works.  Therefore, we can pass additional
    parameters to suppress diagnostic messages, in order not to
    tamper the process output.

  * `tramp-direct-async'
    Whether the method supports direct asynchronous processes.
    Until now, just \"ssh\"-based and \"adb\"-based methods do.

  * `tramp-copy-program'
    This specifies the name of the program to use for remotely copying
    the file; this might be the absolute filename of scp or the name of
    a workalike program.  It is always applied on the local host.

  * `tramp-copy-args'
    This specifies the list of parameters to pass to the above mentioned
    program, the hints for `tramp-login-args' also apply here.

  * `tramp-copy-env'
     A list of environment variables and their values, which will
     be set when calling `tramp-copy-program'.

  * `tramp-remote-copy-program'
    The listener program to be applied on remote side, if needed.

  * `tramp-remote-copy-args'
    The list of parameters to pass to the listener program, the hints
    for `tramp-login-args' also apply here.  Additionally, \"%r\" could
    be used here and in `tramp-copy-args'.  It denotes a randomly
    chosen port for the remote listener.

  * `tramp-copy-keep-date'
    This specifies whether the copying program when the preserves the
    timestamp of the original file.

  * `tramp-copy-keep-tmpfile'
    This specifies whether a temporary local file shall be kept
    for optimization reasons (useful for \"rsync\" methods).

  * `tramp-copy-recursive'
    Whether the operation copies directories recursively.

  * `tramp-default-port'
    The default port of a method.

  * `tramp-tmpdir'
    A directory on the remote host for temporary files.  If not
    specified, \"/tmp\" is taken as default.

  * `tramp-connection-timeout'
    This is the maximum time to be spent for establishing a connection.
    In general, the global default value shall be used, but for
    some methods, like \"su\" or \"sudo\", a shorter timeout
    might be desirable.

  * `tramp-session-timeout'
    How long a Tramp connection keeps open before being disconnected.
    This is useful for methods like \"su\" or \"sudo\", which
    shouldn't run an open connection in the background forever.

  * `tramp-case-insensitive'
    Whether the remote file system handles file names case insensitive.
    Only a non-nil value counts, the default value nil means to
    perform further checks on the remote host.  See
    `tramp-connection-properties' for a way to overwrite this.

  * `tramp-mount-args'
  * `tramp-copyto-args'
  * `tramp-moveto-args'
  * `tramp-about-args'
    These parameters, a list of list like `tramp-login-args', are used
    for the \"rclone\" method, and are appended to the respective
    \"rclone\" commands.  In general, they shouldn't be changed inside
    `tramp-methods'; it is recommended to change their values via
    `tramp-connection-properties'.  Unlike `tramp-login-args' there is
     no pattern replacement.

What does all this mean?  Well, you should specify `tramp-login-program'
for all methods; this program is used to log in to the remote site.  Then,
there are two ways to actually transfer the files between the local and the
remote side.  One way is using an additional scp-like program.  If you want
to do this, set `tramp-copy-program' in the method.

Another possibility for file transfer is inline transfer, i.e. the
file is passed through the same buffer used by `tramp-login-program'.  In
this case, the file contents need to be protected since the
`tramp-login-program' might use escape codes or the connection might not
be eight-bit clean.  Therefore, file contents are encoded for transit.
See the variables `tramp-local-coding-commands' and
`tramp-remote-coding-commands' for details.

So, to summarize: if the method is an out-of-band method, then you
must specify `tramp-copy-program' and `tramp-copy-args'.  If it is an
inline method, then these two parameters should be nil.

Notes:

All these arguments can be overwritten by connection properties.
See Info node `(tramp) Predefined connection information'.

When using `su', `sudo' or `doas' the phrase \"open connection to
a remote host\" sounds strange, but it is used nevertheless, for
consistency.  No connection is opened to a remote host, but `su',
`sudo' or `doas' is started on the local host.  You should
specify a remote host `localhost' or the name of the local host.
Another host name is useful only in combination with
`tramp-default-proxies-alist'.")

(defcustom tramp-default-method
  ;; An external copy method seems to be preferred, because it performs
  ;; much better for large files, and it hasn't too serious delays
  ;; for small files.  But it must be ensured that there aren't
  ;; permanent password queries.  Either a password agent like
  ;; "ssh-agent" or "Pageant" shall run, or the optional
  ;; password-cache.el or auth-sources.el packages shall be active for
  ;; password caching.  If we detect that the user is running OpenSSH
  ;; 4.0 or newer, we could reuse the connection, which calls also for
  ;; an external method.
  (cond
   ;; PuTTY is installed.  We don't take it, if it is installed on a
   ;; non-windows system, or pscp from the pssh (parallel ssh) package
   ;; is found.
   ((and (eq system-type 'windows-nt) (executable-find "pscp")) "pscp")
   ;; There is an ssh installation.
   ((executable-find "scp") "scp")
   ;; Fallback.
   (t "ftp"))
  "Default method to use for transferring files.
See `tramp-methods' for possibilities.
Also see `tramp-default-method-alist'."
  :type 'string)

(defcustom tramp-default-method-alist nil
  ;; FIXME: This is not an "alist", because its elements are not of
  ;; the form (KEY . VAL) but (KEY1 KEY2 VAL).
  "Default method to use for specific host/user pairs.
This is an alist of items (HOST USER METHOD).  The first matching item
specifies the method to use for a file name which does not specify a
method.  HOST and USER are regular expressions or nil, which is
interpreted as a regular expression which always matches.  If no entry
matches, the variable `tramp-default-method' takes effect.

If the file name does not specify the user, lookup is done using the
empty string for the user name.

See `tramp-methods' for a list of possibilities for METHOD."
  :type '(repeat (list (choice :tag "Host regexp" regexp sexp)
		       (choice :tag "User regexp" regexp sexp)
		       (choice :tag "Method name" string (const nil)))))

(defconst tramp-default-method-marker "-"
  "Marker for default method in remote file names.")

(defcustom tramp-default-user nil
  "Default user to use for transferring files.
It is nil by default; otherwise settings in configuration files like
\"~/.ssh/config\" would be overwritten.  Also see `tramp-default-user-alist'.

This variable is regarded as obsolete, and will be removed soon."
  :type '(choice (const nil) string))

(defcustom tramp-default-user-alist nil
  ;; FIXME: This is not an "alist", because its elements are not of
  ;; the form (KEY . VAL) but (KEY1 KEY2 VAL).
  "Default user to use for specific method/host pairs.
This is an alist of items (METHOD HOST USER).  The first matching item
specifies the user to use for a file name which does not specify a
user.  METHOD and HOST are regular expressions or nil, which is
interpreted as a regular expression which always matches.  If no entry
matches, the variable `tramp-default-user' takes effect.

If the file name does not specify the method, lookup is done using the
empty string for the method name."
  :type '(repeat (list (choice :tag "Method regexp" regexp sexp)
		       (choice :tag "  Host regexp" regexp sexp)
		       (choice :tag "    User name" string (const nil)))))

(defcustom tramp-default-host tramp-system-name
  "Default host to use for transferring files.
Useful for su and sudo methods mostly."
  :type 'string)

(defcustom tramp-default-host-alist nil
  ;; FIXME: This is not an "alist", because its elements are not of
  ;; the form (KEY . VAL) but (KEY1 KEY2 VAL).
  "Default host to use for specific method/user pairs.
This is an alist of items (METHOD USER HOST).  The first matching item
specifies the host to use for a file name which does not specify a
host.  METHOD and USER are regular expressions or nil, which is
interpreted as a regular expression which always matches.  If no entry
matches, the variable `tramp-default-host' takes effect.

If the file name does not specify the method, lookup is done using the
empty string for the method name."
  :version "24.4"
  :type '(repeat (list (choice :tag "Method regexp" regexp sexp)
		       (choice :tag "  User regexp" regexp sexp)
		       (choice :tag "    Host name" string (const nil)))))

(defcustom tramp-default-proxies-alist nil
  ;; FIXME: This is not an "alist", because its elements are not of
  ;; the form (KEY . VAL) but (KEY1 KEY2 VAL).
  "Route to be followed for specific host/user pairs.
This is an alist of items (HOST USER PROXY).  The first matching
item specifies the proxy to be passed for a file name located on
a remote target matching USER@HOST.  HOST and USER are regular
expressions, which could also cover a domain (USER%DOMAIN) or
port (HOST#PORT).  PROXY must be a Tramp filename without a
localname part.  Method and user name on PROXY are optional,
which is interpreted with the default values.

PROXY can contain the patterns %h and %u, which are replaced by
the strings matching HOST or USER (without DOMAIN and PORT parts),
respectively.

If an entry is added while parsing ad-hoc hop definitions, PROXY
carries the non-nil text property `tramp-ad-hoc'.

HOST, USER or PROXY could also be Lisp forms, which will be
evaluated.  The result must be a string or nil, which is
interpreted as a regular expression which always matches."
  :type '(repeat (list (choice :tag "Host regexp" regexp sexp)
		       (choice :tag "User regexp" regexp sexp)
		       (choice :tag " Proxy name" string (const nil)))))

(defcustom tramp-save-ad-hoc-proxies nil
  "Whether to save ad-hoc proxies persistently."
  :version "24.3"
  :type 'boolean)

;; For some obscure technical reasons, `system-name' on w32 returns
;; either lower case or upper case letters.  See
;; <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=38079#20>.
(defcustom tramp-restricted-shell-hosts-alist
  (when (memq system-type '(windows-nt))
    (list (format "\\`\\(%s\\|%s\\)\\'"
		  (regexp-quote (downcase tramp-system-name))
		  (regexp-quote (upcase tramp-system-name)))))
  "List of hosts, which run a restricted shell.
This is a list of regular expressions, which denote hosts running
a restricted shell like \"rbash\".  Those hosts can be used as
proxies only, see `tramp-default-proxies-alist'.  If the local
host runs a restricted shell, it shall be added to this list, too."
  :version "27.1"
  :type '(repeat (regexp :tag "Host regexp")))

(defcustom tramp-local-host-regexp
  (concat
   "\\`"
   (regexp-opt
    (list "localhost" "localhost6" tramp-system-name "127.0.0.1" "::1") t)
   "\\'")
  "Host names which are regarded as local host.
If the local host runs a chrooted environment, set this to nil."
  :version "27.1"
  :type '(choice (const :tag "Chrooted environment" nil)
		 (regexp :tag "Host regexp")))

(defvar tramp-completion-function-alist nil
  "Alist of methods for remote files.
This is a list of entries of the form \(NAME PAIR1 PAIR2 ...).
Each NAME stands for a remote access method.  Each PAIR is of the form
\(FUNCTION FILE).  FUNCTION is responsible to extract user names and host
names from FILE for completion.  The following predefined FUNCTIONs exists:

 * `tramp-parse-rhosts'      for \"~/.rhosts\" like files,
 * `tramp-parse-shosts'      for \"~/.ssh/known_hosts\" like files,
 * `tramp-parse-sconfig'     for \"~/.ssh/config\" like files,
 * `tramp-parse-shostkeys'   for \"~/.ssh2/hostkeys/*\" like files,
 * `tramp-parse-sknownhosts' for \"~/.ssh2/knownhosts/*\" like files,
 * `tramp-parse-hosts'       for \"/etc/hosts\" like files,
 * `tramp-parse-passwd'      for \"/etc/passwd\" like files.
 * `tramp-parse-etc-group'   for \"/etc/group\" like files.
 * `tramp-parse-netrc'       for \"~/.netrc\" like files.
 * `tramp-parse-putty'       for PuTTY registered sessions.

FUNCTION can also be a user defined function.  For more details see
the info pages.")

(defconst tramp-echo-mark-marker "_echo"
  "String marker to surround echoed commands.")

(defconst tramp-echo-mark-marker-length (length tramp-echo-mark-marker)
  "String length of `tramp-echo-mark-marker'.")

(defconst tramp-echo-mark
  (concat tramp-echo-mark-marker
	  (make-string tramp-echo-mark-marker-length ?\b))
  "String mark to be transmitted around shell commands.
Used to separate their echo from the output they produce.  This
will only be used if we cannot disable remote echo via stty.
This string must have no effect on the remote shell except for
producing some echo which can later be detected by
`tramp-echoed-echo-mark-regexp'.  Using `tramp-echo-mark-marker',
followed by an equal number of backspaces to erase them will
usually suffice.")

(defconst tramp-echoed-echo-mark-regexp
  (format "%s\\(\b\\( \b\\)?\\)\\{%d\\}"
	  tramp-echo-mark-marker tramp-echo-mark-marker-length)
  "Regexp which matches `tramp-echo-mark' as it gets echoed by \
the remote shell.")

(defcustom tramp-local-end-of-line
  (if (memq system-type '(windows-nt)) "\r\n" "\n")
  "String used for end of line in local processes."
  :version "24.1"
  :type 'string)

(defcustom tramp-rsh-end-of-line "\n"
  "String used for end of line in rsh connections.
I don't think this ever needs to be changed, so please tell me about it
if you need to change this."
  :type 'string)

(defcustom tramp-login-prompt-regexp
  ".*\\(user\\|login\\)\\( .*\\)?: *"
  "Regexp matching login-like prompts.
The regexp should match at end of buffer.

Sometimes the prompt is reported to look like \"login as:\"."
  :type 'regexp)

(defcustom tramp-shell-prompt-pattern
  ;; Allow a prompt to start right after a ^M since it indeed would be
  ;; displayed at the beginning of the line (and Zsh uses it).  This
  ;; regexp works only for GNU Emacs.
  ;; Allow also [] style prompts.  They can appear only during
  ;; connection initialization; Tramp redefines the prompt afterwards.
  (concat "\\(?:^\\|\r\\)"
	  "[^]#$%>\n]*#?[]#$%>] *\\(\e\\[[[:digit:];]*[[:alpha:]] *\\)*")
  "Regexp to match prompts from remote shell.
Normally, Tramp expects you to configure `shell-prompt-pattern'
correctly, but sometimes it happens that you are connecting to a
remote host which sends a different kind of shell prompt.  Therefore,
Tramp recognizes things matched by `shell-prompt-pattern' as prompt,
and also things matched by this variable.  The default value of this
variable is similar to the default value of `shell-prompt-pattern',
which should work well in many cases.

This regexp must match both `tramp-initial-end-of-output' and
`tramp-end-of-output'."
  :type 'regexp)

(defcustom tramp-password-prompt-regexp
  (format "^.*\\(%s\\).*:\^@? *" (regexp-opt password-word-equivalents))
  "Regexp matching password-like prompts.
The regexp should match at end of buffer.

This variable is, by default, initialised from
`password-word-equivalents' when Tramp is loaded, and it is
usually more convenient to add new passphrases to that variable
instead of altering this variable.

The `sudo' program appears to insert a `^@' character into the prompt."
  :version "24.4"
  :type 'regexp)

(defcustom tramp-wrong-passwd-regexp
  (concat "^.*"
	  ;; These strings should be on the last line
	  (regexp-opt '("Permission denied"
			"Login incorrect"
			"Login Incorrect"
			"Connection refused"
			"Connection closed"
			"Timeout, server not responding."
			"Sorry, try again."
			"Name or service not known"
			"Host key verification failed."
			"No supported authentication methods left to try!")
		      t)
	  ".*"
	  "\\|"
	  "^.*\\("
	  ;; Here comes a list of regexes, separated by \\|
	  "Received signal [[:digit:]]+"
	  "\\).*")
  "Regexp matching a `login failed' message.
The regexp should match at end of buffer."
  :type 'regexp)

(defcustom tramp-yesno-prompt-regexp
  (concat
   (regexp-opt
    '("Are you sure you want to continue connecting (yes/no)?"
      "Are you sure you want to continue connecting (yes/no/[fingerprint])?")
    t)
   "\\s-*")
  "Regular expression matching all yes/no queries which need to be confirmed.
The confirmation should be done with yes or no.
The regexp should match at end of buffer.
See also `tramp-yn-prompt-regexp'."
  :type 'regexp)

(defcustom tramp-yn-prompt-regexp
  (concat
   (regexp-opt '("Store key in cache? (y/n)"
		 "Update cached key? (y/n, Return cancels connection)")
               t)
   "\\s-*")
  "Regular expression matching all y/n queries which need to be confirmed.
The confirmation should be done with y or n.
The regexp should match at end of buffer.
See also `tramp-yesno-prompt-regexp'."
  :type 'regexp)

(defcustom tramp-terminal-type "dumb"
  "Value of TERM environment variable for logging in to remote host.
Because Tramp wants to parse the output of the remote shell, it is easily
confused by ANSI color escape sequences and suchlike.  Often, shell init
files conditionalize this setup based on the TERM environment variable."
  :group 'tramp
  :type 'string)

(defcustom tramp-terminal-prompt-regexp
  (concat "\\("
	  "TERM = (.*)"
	  "\\|"
	  "Terminal type\\? \\[.*\\]"
	  "\\)\\s-*")
  "Regular expression matching all terminal setting prompts.
The regexp should match at end of buffer.
The answer will be provided by `tramp-action-terminal', which see."
  :type 'regexp)

;; Plink 0.71 has added an additional anti-spoofing prompt after
;; authentication.  This could be discarded with the argument
;; "-no-antispoof".  However, since we don't know which PuTTY
;; version is installed, we must react interactively.
(defcustom tramp-antispoof-regexp
  (regexp-quote "Access granted. Press Return to begin session. ")
  "Regular expression matching plink's anti-spoofing message.
The regexp should match at end of buffer."
  :version "27.1"
  :type 'regexp)

;; Powershell requires "ssh -t -t" for terminal emulation.  If it
;; doesn't fit, there is an error.
(defcustom tramp-no-job-control-regexp
  (regexp-quote "Thus no job control in this shell.")
  "Regular expression matching powershell's job control message.
The regexp should match at end of buffer."
  :version "28.1"
  :type 'regexp)

(defcustom tramp-operation-not-permitted-regexp
  (concat "\\(" "preserving times.*" "\\|" "set mode" "\\)" ":\\s-*"
	  (regexp-opt '("Operation not permitted") t))
  "Regular expression matching keep-date problems in (s)cp operations.
Copying has been performed successfully already, so this message can
be ignored safely."
  :type 'regexp)

(defcustom tramp-copy-failed-regexp
  (concat "\\(.+: "
          (regexp-opt '("Permission denied"
                        "not a regular file"
                        "is a directory"
                        "No such file or directory")
                      t)
          "\\)\\s-*")
  "Regular expression matching copy problems in (s)cp operations."
  :type 'regexp)

(defcustom tramp-process-alive-regexp
  ""
  "Regular expression indicating a process has finished.
In fact this expression is empty by intention, it will be used only to
check regularly the status of the associated process.
The answer will be provided by `tramp-action-process-alive',
`tramp-action-out-of-band', which see."
  :type 'regexp)

(defconst tramp-temp-name-prefix "tramp."
  "Prefix to use for temporary files.
If this is a relative file name (such as \"tramp.\"), it is considered
relative to the directory name returned by the function
`tramp-compat-temporary-file-directory' (which see).  It may also be an
absolute file name; don't forget to include a prefix for the filename
part, though.")

(defconst tramp-temp-buffer-name " *tramp temp*"
  "Buffer name for a temporary buffer.
It shall be used in combination with `generate-new-buffer-name'.")

(defvar tramp-temp-buffer-file-name nil
  "File name of a persistent local temporary file.
Useful for \"rsync\" like methods.")
(make-variable-buffer-local 'tramp-temp-buffer-file-name)
(put 'tramp-temp-buffer-file-name 'permanent-local t)

(defcustom tramp-syntax 'default
  "Tramp filename syntax to be used.

It can have the following values:

  `default'    -- Default syntax
  `simplified' -- Ange-FTP like syntax
  `separate'   -- Syntax as defined for XEmacs originally

Do not change the value by `setq', it must be changed only via
Customize.  See also `tramp-change-syntax'."
  :version "26.1"
  :package-version '(Tramp . "2.3.3")
  :type '(choice (const :tag "Default" default)
		 (const :tag "Ange-FTP" simplified)
		 (const :tag "XEmacs" separate))
  :require 'tramp
  :initialize #'custom-initialize-default
  :set #'tramp-set-syntax)

(defun tramp-set-syntax (symbol value)
  "Set SYMBOL to value VALUE.
Used in user option `tramp-syntax'.  There are further variables
to be set, depending on VALUE."
  ;; Check allowed values.
  (unless (memq value (tramp-syntax-values))
    (tramp-user-error nil "Wrong `tramp-syntax' %s" value))
  ;; Cleanup existing buffers.
  (unless (eq (symbol-value symbol) value)
    (tramp-cleanup-all-buffers))
  ;; Set the value:
  (set-default symbol value)
  ;; Reset the depending variables.
  (with-no-warnings
    (setq tramp-prefix-format (tramp-build-prefix-format)
	  tramp-prefix-regexp (tramp-build-prefix-regexp)
	  tramp-method-regexp (tramp-build-method-regexp)
	  tramp-postfix-method-format (tramp-build-postfix-method-format)
	  tramp-postfix-method-regexp (tramp-build-postfix-method-regexp)
	  tramp-prefix-ipv6-format (tramp-build-prefix-ipv6-format)
	  tramp-prefix-ipv6-regexp (tramp-build-prefix-ipv6-regexp)
	  tramp-postfix-ipv6-format (tramp-build-postfix-ipv6-format)
	  tramp-postfix-ipv6-regexp (tramp-build-postfix-ipv6-regexp)
	  tramp-postfix-host-format (tramp-build-postfix-host-format)
	  tramp-postfix-host-regexp (tramp-build-postfix-host-regexp)
	  tramp-remote-file-name-spec-regexp
	  (tramp-build-remote-file-name-spec-regexp)
	  tramp-file-name-structure (tramp-build-file-name-structure)
	  tramp-file-name-regexp (tramp-build-file-name-regexp)
	  tramp-completion-file-name-regexp
          (tramp-build-completion-file-name-regexp)))
  ;; Rearrange file name handlers.
  (tramp-register-file-name-handlers))

;; Initialize the Tramp syntax variables.  We want to override initial
;; value of `tramp-file-name-regexp'.  Other Tramp syntax variables
;; must be initialized as well to proper values.  We do not call
;; `custom-set-variable', this would load Tramp via custom.el.
(tramp--with-startup
  (tramp-set-syntax 'tramp-syntax (tramp-compat-tramp-syntax)))

(defun tramp-syntax-values ()
  "Return possible values of `tramp-syntax', a list."
  (let ((values (cdr (get 'tramp-syntax 'custom-type))))
    (setq values (mapcar #'last values)
	  values (mapcar #'car values))
    values))

(defun tramp-lookup-syntax (alist)
  "Look up a syntax string in ALIST according to `tramp-compat-tramp-syntax'.
Raise an error if `tramp-syntax' is invalid."
  (or (cdr (assq (tramp-compat-tramp-syntax) alist))
      (error "Wrong `tramp-syntax' %s" tramp-syntax)))

(defconst tramp-prefix-format-alist
  '((default    . "/")
    (simplified . "/")
    (separate   . "/["))
  "Alist mapping Tramp syntax to strings beginning Tramp file names.")

(defun tramp-build-prefix-format ()
  "Return `tramp-prefix-format' according to `tramp-syntax'."
  (tramp-lookup-syntax tramp-prefix-format-alist))

(defvar tramp-prefix-format nil ;Initialized when defining `tramp-syntax'!
  "String matching the very beginning of Tramp file names.
Used in `tramp-make-tramp-file-name'.")

(defun tramp-build-prefix-regexp ()
  "Return `tramp-prefix-regexp'."
  (concat "^" (regexp-quote tramp-prefix-format)))

(defvar tramp-prefix-regexp nil ;Initialized when defining `tramp-syntax'!
  "Regexp matching the very beginning of Tramp file names.
Should always start with \"^\". Derived from `tramp-prefix-format'.")

(defconst tramp-method-regexp-alist
  '((default    . "[[:alnum:]-]+")
    (simplified . "")
    (separate   . "[[:alnum:]-]*"))
  "Alist mapping Tramp syntax to regexps matching methods identifiers.")

(defun tramp-build-method-regexp ()
  "Return `tramp-method-regexp' according to `tramp-syntax'."
  (tramp-lookup-syntax tramp-method-regexp-alist))

(defvar tramp-method-regexp nil ;Initialized when defining `tramp-syntax'!