emacs/lisp/net/tramp-androidsu.el

550 lines
24 KiB
EmacsLisp

;;; tramp-androidsu.el --- Tramp method for Android superuser shells -*- lexical-binding:t -*-
;; Copyright (C) 2024 Free Software Foundation, Inc.
;; Author: Po Lu
;; 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:
;; `su' method implementation for Android.
;;
;; The `su' method struggles (as do other shell-based methods) with the
;; crippled versions of many Unix utilities installed on Android,
;; workarounds for which are implemented in the `adb' method. This
;; method defines a shell-based method that is identical in function to
;; and replaces if connecting to a local Android machine `su', but
;; reuses such code from the `adb' method where applicable and also
;; provides for certain mannerisms of popular Android `su'
;; implementations.
;;; Code:
(require 'tramp)
(require 'tramp-adb)
(require 'tramp-sh)
;;;###tramp-autoload
(defconst tramp-androidsu-method "androidsu"
"When this method name is used, forward all calls to su.")
;;;###tramp-autoload
(defcustom tramp-androidsu-mount-global-namespace t
"When non-nil, browse files from within the global mount namespace.
On systems that assign each application a unique view of the
filesystem by executing them within individual mount namespaces
and thus conceal each application's data directories from
others, invoke `su' with the option `-mm' in order for the shell
launched to run within the global mount namespace, so that Tramp
may edit files belonging to any and all applications."
:group 'tramp
:version "30.1"
:type 'boolean)
;;;###tramp-autoload
(defcustom tramp-androidsu-remote-path '("/system/bin"
"/system/xbin")
"Directories in which to search for transfer programs and the like."
:group 'tramp
:version "30.1"
:type '(repeat string))
(defvar tramp-androidsu-su-mm-supported 'unknown
"Whether `su -mm' is supported on this system.")
;;;###tramp-autoload
(defconst tramp-androidsu-local-shell-name "/system/bin/sh"
"Name of the local shell on Android.")
;;;###tramp-autoload
(defconst tramp-androidsu-local-tmp-directory "/data/local/tmp"
"Name of the local temporary directory on Android.")
;;;###tramp-autoload
(defun tramp-enable-androidsu-method ()
"Enable \"androidsu\" method."
(add-to-list 'tramp-methods
`(,tramp-androidsu-method
(tramp-login-program "su")
(tramp-login-args (("-") ("%u")))
(tramp-remote-shell ,tramp-androidsu-local-shell-name)
(tramp-remote-shell-login ("-l"))
(tramp-remote-shell-args ("-c"))
(tramp-tmpdir ,tramp-androidsu-local-tmp-directory)
(tramp-connection-timeout 10)
(tramp-shell-name ,tramp-androidsu-local-shell-name)))
(add-to-list 'tramp-default-user-alist
`(,(rx bos (literal tramp-androidsu-method) eos)
nil ,tramp-root-id-string)))
;;;###tramp-autoload
(tramp--with-startup
(when (eq system-type 'android)
(tramp-enable-androidsu-method)))
(defvar android-use-exec-loader) ; androidfns.c.
(defun tramp-androidsu-maybe-open-connection (vec)
"Open a connection VEC if not already open.
Mostly identical to `tramp-adb-maybe-open-connection', but also disables
multibyte mode and waits for the shell prompt to appear."
;; During completion, don't reopen a new connection.
(unless (tramp-connectable-p vec)
(throw 'non-essential 'non-essential))
(with-tramp-debug-message vec "Opening connection"
(let ((p (tramp-get-connection-process vec))
(process-name (tramp-get-connection-property vec " process-name"))
(process-environment (copy-sequence process-environment)))
;; Open a new connection.
(condition-case err
(unless (process-live-p p)
(with-tramp-progress-reporter
vec 3
(format "Opening connection%s for %s%s using %s"
(if (tramp-string-empty-or-nil-p process-name)
"" (concat " " process-name))
(if (tramp-string-empty-or-nil-p
(tramp-file-name-user vec))
"" (concat (tramp-file-name-user vec) "@"))
(tramp-file-name-host vec)
(tramp-file-name-method vec))
(let* ((coding-system-for-read 'utf-8-unix)
(process-connection-type tramp-process-connection-type)
;; The executable loader cannot execute setuid
;; binaries, such as su.
(android-use-exec-loader nil)
(p (start-process (tramp-get-connection-name vec)
(tramp-get-connection-buffer vec)
;; Disregard
;; `tramp-encoding-shell', as
;; there's no guarantee that it's
;; possible to execute it with
;; `android-use-exec-loader' off.
tramp-androidsu-local-shell-name "-i"))
(user (tramp-file-name-user vec))
su-binary path command)
;; Set sentinel. Initialize variables.
(set-process-sentinel p #'tramp-process-sentinel)
(tramp-post-process-creation p vec)
;; Replace `login-args' place holders. `PATH' must be
;; set to `tramp-androidsu-remote-path', as some `su'
;; implementations propagate their callers' environments
;; to the root session, which might be contaminated with
;; incompatible `ls' binaries or similar.
(setq path (tramp-shell-quote-argument
(string-join tramp-androidsu-remote-path ":"))
su-binary
(shell-quote-argument
(or (executable-find "su")
(tramp-user-error
vec
"No su binary is available in any of `exec-path'")))
command (format "PATH=%s exec %s - %s || exit"
path su-binary user))
;; Attempt to execute the shell inside the global mount
;; namespace if requested.
(when tramp-androidsu-mount-global-namespace
(progn
(when (eq tramp-androidsu-su-mm-supported 'unknown)
;; Change the prompt in advance so that
;; `tramp-adb-send-command-and-check' can call
;; `tramp-search-regexp'.
(tramp-adb-send-command
vec (format "PS1=%s PS2=''"
(tramp-shell-quote-argument
tramp-end-of-output)))
(setq tramp-androidsu-su-mm-supported
;; Detect support for `su -mm'.
(tramp-adb-send-command-and-check
vec (format "%s -mm -c 'exit 24'" su-binary)
24)))
(when tramp-androidsu-su-mm-supported
(tramp-set-connection-property
vec "remote-namespace" t)
(setq command (format "PATH=%s exec %s -mm - %s || exit"
path su-binary user)))))
;; Send the command.
(tramp-message vec 3 "Sending command `%s'" command)
(tramp-adb-send-command vec command t t)
;; Android su binaries contact a background service to
;; obtain authentication; during this process, input
;; received is discarded, so input cannot be
;; guaranteed to reach the root shell until its prompt
;; is displayed.
(with-current-buffer (process-buffer p)
(tramp-wait-for-regexp p tramp-connection-timeout
"#[[:space:]]*$"))
;; Set connection-local variables.
(tramp-set-connection-local-variables vec)
;; Change prompt.
(tramp-adb-send-command
vec (format "PS1=%s PS2=''"
(tramp-shell-quote-argument tramp-end-of-output)))
;; Disable line editing.
(tramp-adb-send-command
vec "set +o vi +o vi-esccomplete +o vi-tabcomplete +o emacs")
;; Disable Unicode, for otherwise Unicode filenames will
;; not be decoded correctly.
(tramp-adb-send-command vec "set +U")
;; Dump option settings in the traces.
(when (>= tramp-verbose 9)
(tramp-adb-send-command vec "set -o"))
;; Disable echo expansion.
(tramp-adb-send-command
vec "stty -inlcr -onlcr -echo kill '^U' erase '^H'" t)
;; Check whether the echo has really been disabled.
;; Some implementations, like busybox, don't support
;; disabling.
(tramp-adb-send-command vec "echo foo" t)
(with-current-buffer (process-buffer p)
(goto-char (point-min))
(when (looking-at-p "echo foo")
(tramp-set-connection-property p "remote-echo" t)
(tramp-message vec 5 "Remote echo still on. Ok.")
;; Make sure backspaces and their echo are enabled
;; and no line width magic interferes with them.
(tramp-adb-send-command
vec "stty icanon erase ^H cols 32767" t)))
;; Mark it as connected.
(tramp-set-connection-property p "connected" t))))
;; Cleanup, and propagate the signal.
((error quit)
(tramp-cleanup-connection vec t)
(signal (car err) (cdr err)))))))
(defun tramp-androidsu-generate-wrapper (function)
"Return connection wrapper function for FUNCTION.
Return a function which temporarily substitutes local replacements for
the `adb' method's connection management functions around a call to
FUNCTION."
(lambda (&rest args)
(let ((tramp-adb-wait-for-output
(symbol-function #'tramp-adb-wait-for-output))
(tramp-adb-maybe-open-connection
(symbol-function #'tramp-adb-maybe-open-connection)))
(unwind-protect
(progn
;; `tramp-adb-wait-for-output' addresses problems introduced
;; by the adb utility itself, not Android utilities, so
;; replace it with the regular Tramp function.
(fset 'tramp-adb-wait-for-output #'tramp-wait-for-output)
;; Likewise, except some special treatment is necessary on
;; account of flaws in Android's su implementation.
(fset 'tramp-adb-maybe-open-connection
#'tramp-androidsu-maybe-open-connection)
(apply function args))
;; Restore the original definitions of the functions overridden
;; above.
(fset 'tramp-adb-wait-for-output tramp-adb-wait-for-output)
(fset 'tramp-adb-maybe-open-connection
tramp-adb-maybe-open-connection)))))
(defalias 'tramp-androidsu-handle-copy-file #'tramp-sh-handle-copy-file)
(defalias 'tramp-androidsu-handle-delete-directory
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-delete-directory))
(defalias 'tramp-androidsu-handle-delete-file
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-delete-file))
(defalias 'tramp-androidsu-handle-directory-files-and-attributes
(tramp-androidsu-generate-wrapper
#'tramp-adb-handle-directory-files-and-attributes))
(defalias 'tramp-androidsu-handle-exec-path
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-exec-path))
(defalias 'tramp-androidsu-handle-file-attributes
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-file-attributes))
(defalias 'tramp-androidsu-handle-file-executable-p
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-file-executable-p))
(defalias 'tramp-androidsu-handle-file-exists-p
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-file-exists-p))
(defalias 'tramp-androidsu-handle-file-local-copy
#'tramp-sh-handle-file-local-copy)
(defalias 'tramp-androidsu-handle-file-name-all-completions
(tramp-androidsu-generate-wrapper
#'tramp-adb-handle-file-name-all-completions))
(defalias 'tramp-androidsu-handle-file-readable-p
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-file-readable-p))
(defalias 'tramp-androidsu-handle-file-system-info
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-file-system-info))
(defalias 'tramp-androidsu-handle-file-writable-p
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-file-writable-p))
(defalias 'tramp-androidsu-handle-make-directory
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-make-directory))
(defun tramp-androidsu-handle-make-process (&rest args)
"Like `tramp-handle-make-process', but modified for Android."
(tramp-skeleton-make-process args nil nil
(let* ((env (mapcar
(lambda (elt) (when (string-search "=" elt) elt))
tramp-remote-process-environment))
;; We use as environment the difference to toplevel
;; `process-environment'.
(env (dolist (elt process-environment env)
(when
(and
(string-search "=" elt)
(not
(member
elt (default-toplevel-value 'process-environment))))
(setq env (cons elt env)))))
;; Add remote path if exists.
(env (let ((remote-path (string-join (tramp-get-remote-path v) ":")))
(setenv-internal env "PATH" remote-path 'keep)))
(env (setenv-internal env "INSIDE_EMACS" (tramp-inside-emacs) 'keep))
(env (mapcar #'tramp-shell-quote-argument (delq nil env)))
;; Quote command.
(command (mapconcat #'tramp-shell-quote-argument command " "))
;; Set cwd and environment variables.
(command
(append
`("cd" ,(tramp-shell-quote-argument localname) "&&" "(" "env")
env `(,command ")")))
;; Add remote shell if needed.
(command
(if (consp (tramp-get-method-parameter v 'tramp-direct-async))
(append
(tramp-get-method-parameter v 'tramp-direct-async)
`(,(string-join command " ")))
command))
p)
;; Generate a command to start the process using `su' with
;; suitable options for specifying the mount namespace and
;; suchlike.
;; Suppress `internal-default-process-sentinel', which is set
;; when :sentinel is nil. (Bug#71049)
(setq
p (let ((android-use-exec-loader nil))
(make-process
:name name
:buffer buffer
:command
(if (equal user "root")
;; Invoke su in the simplest manner possible, that
;; is to say, without specifying the user, which
;; certain implementations cannot parse when a
;; command is also present, if it may be omitted, so
;; that starting inferior shells on systems with
;; such implementations does not needlessly fail.
(if (tramp-get-connection-property v "remote-namespace")
(append (list "su" "-mm" "-c") command)
(append (list "su" "-c") command))
(if (tramp-get-connection-property v "remote-namespace")
(append (list "su" "-mm" "-" user "-c") command)
(append (list "su" "-" user "-c") command)))
:coding coding
:noquery noquery
:connection-type connection-type
:sentinel (or sentinel #'ignore)
:stderr stderr)))
;; Set filter. Prior Emacs 29.1, it doesn't work reliably to
;; provide it as `make-process' argument when filter is t. See
;; Bug#51177.
(when filter
(set-process-filter p filter))
(tramp-post-process-creation p v)
;; Query flag is overwritten in `tramp-post-process-creation',
;; so we reset it.
(set-process-query-on-exit-flag p (null noquery))
(process-put p 'remote-command orig-command)
(tramp-set-connection-property p "remote-command" orig-command)
(when (bufferp stderr)
(tramp-taint-remote-process-buffer stderr))
p)))
(defalias 'tramp-androidsu-handle-make-symbolic-link
#'tramp-sh-handle-make-symbolic-link)
(defalias 'tramp-androidsu-handle-process-file
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-process-file))
(defalias 'tramp-androidsu-handle-rename-file #'tramp-sh-handle-rename-file)
(defalias 'tramp-androidsu-handle-set-file-modes
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-set-file-modes))
(defalias 'tramp-androidsu-handle-set-file-times
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-set-file-times))
(defalias 'tramp-androidsu-handle-get-remote-gid
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-get-remote-gid))
(defalias 'tramp-androidsu-handle-get-remote-groups
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-get-remote-groups))
(defalias 'tramp-androidsu-handle-get-remote-uid
(tramp-androidsu-generate-wrapper #'tramp-adb-handle-get-remote-uid))
(defalias 'tramp-androidsu-handle-write-region #'tramp-sh-handle-write-region)
;;;###tramp-autoload
(defconst tramp-androidsu-file-name-handler-alist
'(;; `abbreviate-file-name' performed by default handler.
(access-file . tramp-handle-access-file)
(add-name-to-file . tramp-handle-add-name-to-file)
;; `byte-compiler-base-file-name' performed by default handler.
(copy-directory . tramp-handle-copy-directory)
(copy-file . tramp-androidsu-handle-copy-file)
(delete-directory . tramp-androidsu-handle-delete-directory)
(delete-file . tramp-androidsu-handle-delete-file)
;; `diff-latest-backup-file' performed by default handler.
(directory-file-name . tramp-handle-directory-file-name)
(directory-files . tramp-handle-directory-files)
(directory-files-and-attributes
. tramp-androidsu-handle-directory-files-and-attributes)
(dired-compress-file . ignore)
(dired-uncache . tramp-handle-dired-uncache)
(exec-path . tramp-androidsu-handle-exec-path)
(expand-file-name . tramp-handle-expand-file-name)
(file-accessible-directory-p . tramp-handle-file-accessible-directory-p)
(file-acl . ignore)
(file-attributes . tramp-androidsu-handle-file-attributes)
(file-directory-p . tramp-handle-file-directory-p)
(file-equal-p . tramp-handle-file-equal-p)
(file-executable-p . tramp-androidsu-handle-file-executable-p)
(file-exists-p . tramp-androidsu-handle-file-exists-p)
(file-group-gid . tramp-handle-file-group-gid)
(file-in-directory-p . tramp-handle-file-in-directory-p)
(file-local-copy . tramp-androidsu-handle-file-local-copy)
(file-locked-p . tramp-handle-file-locked-p)
(file-modes . tramp-handle-file-modes)
(file-name-all-completions
. tramp-androidsu-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 . tramp-handle-file-notify-add-watch)
(file-notify-rm-watch . tramp-handle-file-notify-rm-watch)
(file-notify-valid-p . tramp-handle-file-notify-valid-p)
(file-ownership-preserved-p . ignore)
(file-readable-p . tramp-androidsu-handle-file-readable-p)
(file-regular-p . tramp-handle-file-regular-p)
(file-remote-p . tramp-handle-file-remote-p)
(file-selinux-context . tramp-handle-file-selinux-context)
(file-symlink-p . tramp-handle-file-symlink-p)
(file-system-info . tramp-androidsu-handle-file-system-info)
(file-truename . tramp-handle-file-truename)
(file-user-uid . tramp-handle-file-user-uid)
(file-writable-p . tramp-androidsu-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)
(list-system-processes . tramp-handle-list-system-processes)
(load . tramp-handle-load)
(lock-file . tramp-handle-lock-file)
(make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
(make-directory . tramp-androidsu-handle-make-directory)
(make-directory-internal . ignore)
(make-lock-file-name . tramp-handle-make-lock-file-name)
(make-nearby-temp-file . tramp-handle-make-nearby-temp-file)
(make-process . tramp-androidsu-handle-make-process)
(make-symbolic-link . tramp-androidsu-handle-make-symbolic-link)
(memory-info . tramp-handle-memory-info)
(process-attributes . tramp-handle-process-attributes)
(process-file . tramp-androidsu-handle-process-file)
(rename-file . tramp-androidsu-handle-rename-file)
(set-file-acl . ignore)
(set-file-modes . tramp-androidsu-handle-set-file-modes)
(set-file-selinux-context . ignore)
(set-file-times . tramp-androidsu-handle-set-file-times)
(set-visited-file-modtime . tramp-handle-set-visited-file-modtime)
(shell-command . tramp-handle-shell-command)
(start-file-process . tramp-handle-start-file-process)
(substitute-in-file-name . tramp-handle-substitute-in-file-name)
(temporary-file-directory . tramp-handle-temporary-file-directory)
(tramp-get-home-directory . ignore)
(tramp-get-remote-gid . tramp-androidsu-handle-get-remote-gid)
(tramp-get-remote-groups . tramp-androidsu-handle-get-remote-groups)
(tramp-get-remote-uid . tramp-androidsu-handle-get-remote-uid)
(tramp-set-file-uid-gid . ignore)
(unhandled-file-name-directory . ignore)
(unlock-file . tramp-handle-unlock-file)
(vc-registered . ignore)
(verify-visited-file-modtime . tramp-handle-verify-visited-file-modtime)
(write-region . tramp-androidsu-handle-write-region))
"Alist of Tramp handler functions for superuser sessions on Android.")
;; 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-androidsu-file-name-p (vec-or-filename)
"Check whether VEC-OR-FILENAME is for the `androidsu' method."
(and-let* ((vec (tramp-ensure-dissected-file-name vec-or-filename))
((equal (tramp-file-name-method vec) tramp-androidsu-method)))))
;;;###tramp-autoload
(defun tramp-androidsu-file-name-handler (operation &rest args)
"Invoke the `androidsu' handler for OPERATION.
First arg specifies the OPERATION, second arg is a list of
arguments to pass to the OPERATION."
(if-let* ((fn (assoc operation tramp-androidsu-file-name-handler-alist)))
(prog1 (save-match-data (apply (cdr fn) args))
(setq tramp-debug-message-fnh-function (cdr fn)))
(prog1 (tramp-run-real-handler operation args)
(setq tramp-debug-message-fnh-function operation))))
;;;###tramp-autoload
(tramp--with-startup
(tramp-register-foreign-file-name-handler
#'tramp-androidsu-file-name-p #'tramp-androidsu-file-name-handler))
;;; Default connection-local variables for Tramp.
(defconst tramp-androidsu-connection-local-default-variables
`((tramp-remote-path . ,tramp-androidsu-remote-path))
"Default connection-local variables for remote androidsu connections.")
(connection-local-set-profile-variables
'tramp-androidsu-connection-local-default-profile
tramp-androidsu-connection-local-default-variables)
(connection-local-set-profiles
`(:application tramp :protocol ,tramp-androidsu-method)
'tramp-androidsu-connection-local-default-profile)
(with-eval-after-load 'shell
(connection-local-set-profiles
`(:application tramp :protocol ,tramp-androidsu-method)
'tramp-adb-connection-local-default-shell-profile
'tramp-adb-connection-local-default-ps-profile))
(add-hook 'tramp-unload-hook
(lambda ()
(unload-feature 'tramp-androidsu 'force)))
(provide 'tramp-androidsu)
;;; tramp-androidsu.el ends here