lisp/net/tramp-compat.el

   1 ;;; tramp-compat.el --- Tramp compatibility functions
   2
   3 ;; Copyright (C) 2007-2011 Free Software Foundation, Inc.
   4
   5 ;; Author: Michael Albinus <michael.albinus@gmx.de>
   6 ;; Keywords: comm, processes
   7 ;; Package: tramp
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Tramp's main Emacs version for development is Emacs 24.  This
  27 ;; package provides compatibility functions for Emacs 22, Emacs 23,
  28 ;; XEmacs 21.4+ and SXEmacs 22.
  29
  30 ;;; Code:
  31
  32 (require 'tramp-loaddefs)
  33
  34 (eval-when-compile
  35
  36   ;; Pacify byte-compiler.
  37   (require 'cl))
  38
  39 (eval-and-compile
  40
  41   (require 'advice)
  42   (require 'custom)
  43   (require 'format-spec)
  44   (require 'shell)
  45
  46   ;; As long as password.el is not part of (X)Emacs, it shouldn't be
  47   ;; mandatory.
  48   (if (featurep 'xemacs)
  49       (load "password" 'noerror)
  50     (or (require 'password-cache nil 'noerror)
  51         (require 'password nil 'noerror))) ; Part of contrib.
  52
  53   ;; auth-source is relatively new.
  54   (if (featurep 'xemacs)
  55       (load "auth-source" 'noerror)
  56     (require 'auth-source nil 'noerror))
  57
  58   ;; Load the appropriate timer package.
  59   (if (featurep 'xemacs)
  60       (require 'timer-funcs)
  61     (require 'timer))
  62
  63   ;; We check whether `start-file-process' is bound.
  64   (unless (fboundp 'start-file-process)
  65
  66     ;; tramp-util offers integration into other (X)Emacs packages like
  67     ;; compile.el, gud.el etc.  Not necessary in Emacs 23.
  68     (eval-after-load "tramp"
  69       '(require 'tramp-util))
  70
  71     ;; Make sure that we get integration with the VC package.  When it
  72     ;; is loaded, we need to pull in the integration module.  Not
  73     ;; necessary in Emacs 23.
  74     (eval-after-load "vc"
  75       (eval-after-load "tramp"
  76         '(require 'tramp-vc))))
  77
  78   ;; Avoid byte-compiler warnings if the byte-compiler supports this.
  79   ;; Currently, XEmacs supports this.
  80   (when (featurep 'xemacs)
  81     (unless (boundp 'byte-compile-default-warnings)
  82       (defvar byte-compile-default-warnings nil))
  83     (delq 'unused-vars byte-compile-default-warnings))
  84
  85   ;; `last-coding-system-used' is unknown in XEmacs.
  86   (unless (boundp 'last-coding-system-used)
  87     (defvar last-coding-system-used nil))
  88
  89   ;; `directory-sep-char' is an obsolete variable in Emacs.  But it is
  90   ;; used in XEmacs, so we set it here and there.  The following is
  91   ;; needed to pacify Emacs byte-compiler.
  92   ;; Note that it was removed altogether in Emacs 24.1.
  93   (when (boundp 'directory-sep-char)
  94     (defvar byte-compile-not-obsolete-var nil)
  95     (setq byte-compile-not-obsolete-var 'directory-sep-char)
  96     ;; Emacs 23.2.
  97     (defvar byte-compile-not-obsolete-vars nil)
  98     (setq byte-compile-not-obsolete-vars '(directory-sep-char)))
  99
 100   ;; `remote-file-name-inhibit-cache' has been introduced with Emacs 24.1.
 101   ;; Besides `t', `nil', and integer, we use also timestamps (as
 102   ;; returned by `current-time') internally.
 103   (defvar remote-file-name-inhibit-cache nil)
 104
 105   ;; For not existing functions, or functions with a changed argument
 106   ;; list, there are compiler warnings.  We want to avoid them in
 107   ;; cases we know what we do.
 108   (defmacro tramp-compat-funcall (function &rest arguments)
 109     (if (featurep 'xemacs)
 110         `(funcall (symbol-function ,function) ,@arguments)
 111       `(when (or (subrp ,function) (functionp ,function))
 112          (with-no-warnings (funcall ,function ,@arguments)))))
 113
 114   ;; `set-buffer-multibyte' comes from Emacs Leim.
 115   (unless (fboundp 'set-buffer-multibyte)
 116     (defalias 'set-buffer-multibyte 'ignore))
 117
 118   ;; The following functions cannot be aliases of the corresponding
 119   ;; `tramp-handle-*' functions, because this would bypass the locking
 120   ;; mechanism.
 121
 122   ;; `file-remote-p' has been introduced with Emacs 22.  The version
 123   ;; of XEmacs is not a magic file name function (yet); this is
 124   ;; corrected in tramp-util.el.  Here it is sufficient if the
 125   ;; function exists.
 126   (unless (fboundp 'file-remote-p)
 127     (defalias 'file-remote-p
 128       (lambda (file &optional identification connected)
 129         (when (tramp-tramp-file-p file)
 130           (tramp-file-name-handler
 131            'file-remote-p file identification connected)))))
 132
 133   ;; `process-file' does not exist in XEmacs.
 134   (unless (fboundp 'process-file)
 135     (defalias 'process-file
 136       (lambda (program &optional infile buffer display &rest args)
 137         (when (tramp-tramp-file-p default-directory)
 138           (apply
 139            'tramp-file-name-handler
 140            'process-file program infile buffer display args)))))
 141
 142   ;; `start-file-process' is new in Emacs 23.
 143   (unless (fboundp 'start-file-process)
 144     (defalias 'start-file-process
 145       (lambda (name buffer program &rest program-args)
 146         (when (tramp-tramp-file-p default-directory)
 147           (apply
 148            'tramp-file-name-handler
 149            'start-file-process name buffer program program-args)))))
 150
 151   ;; `set-file-times' is also new in Emacs 23.
 152   (unless (fboundp 'set-file-times)
 153     (defalias 'set-file-times
 154       (lambda (filename &optional time)
 155         (when (tramp-tramp-file-p filename)
 156           (tramp-file-name-handler
 157            'set-file-times filename time)))))
 158
 159   ;; We currently use "[" and "]" in the filename format for IPv6
 160   ;; hosts of GNU Emacs.  This means that Emacs wants to expand
 161   ;; wildcards if `find-file-wildcards' is non-nil, and then barfs
 162   ;; because no expansion could be found.  We detect this situation
 163   ;; and do something really awful: we have `file-expand-wildcards'
 164   ;; return the original filename if it can't expand anything.  Let's
 165   ;; just hope that this doesn't break anything else.
 166   ;; It is not needed anymore since GNU Emacs 23.2.
 167   (unless (or (featurep 'xemacs)
 168               ;; `featurep' has only one argument in XEmacs.
 169               (funcall 'featurep 'files 'remote-wildcards))
 170     (defadvice file-expand-wildcards
 171       (around tramp-advice-file-expand-wildcards activate)
 172       (let ((name (ad-get-arg 0)))
 173         ;; If it's a Tramp file, look if wildcards need to be expanded
 174         ;; at all.
 175         (if (and
 176              (tramp-tramp-file-p name)
 177              (not (string-match
 178                    "[[*?]" (tramp-compat-funcall
 179                             'file-remote-p name 'localname))))
 180             (setq ad-return-value (list name))
 181           ;; Otherwise, just run the original function.
 182           ad-do-it)))
 183     (add-hook
 184      'tramp-unload-hook
 185      (lambda ()
 186        (ad-remove-advice
 187         'file-expand-wildcards 'around 'tramp-advice-file-expand-wildcards)
 188        (ad-activate 'file-expand-wildcards)))))
 189
 190 ;; `with-temp-message' does not exists in XEmacs.
 191 (if (fboundp 'with-temp-message)
 192     (defalias 'tramp-compat-with-temp-message 'with-temp-message)
 193   (defmacro tramp-compat-with-temp-message (message &rest body)
 194     "Display MESSAGE temporarily if non-nil while BODY is evaluated."
 195     `(progn ,@body)))
 196
 197 ;; `font-lock-add-keywords' does not exist in XEmacs.
 198 (defun tramp-compat-font-lock-add-keywords (mode keywords &optional how)
 199   "Add highlighting KEYWORDS for MODE."
 200   (ignore-errors
 201     (tramp-compat-funcall 'font-lock-add-keywords mode keywords how)))
 202
 203 (defsubst tramp-compat-temporary-file-directory ()
 204   "Return name of directory for temporary files (compat function).
 205 For Emacs, this is the variable `temporary-file-directory', for XEmacs
 206 this is the function `temp-directory'."
 207   (cond
 208    ((boundp 'temporary-file-directory) (symbol-value 'temporary-file-directory))
 209    ((fboundp 'temp-directory) (tramp-compat-funcall 'temp-directory))
 210    ((let ((d (getenv "TEMP"))) (and d (file-directory-p d)))
 211     (file-name-as-directory (getenv "TEMP")))
 212    ((let ((d (getenv "TMP"))) (and d (file-directory-p d)))
 213     (file-name-as-directory (getenv "TMP")))
 214    ((let ((d (getenv "TMPDIR"))) (and d (file-directory-p d)))
 215     (file-name-as-directory (getenv "TMPDIR")))
 216    ((file-exists-p "c:/temp") (file-name-as-directory "c:/temp"))
 217    (t (message (concat "Neither `temporary-file-directory' nor "
 218                        "`temp-directory' is defined -- using /tmp."))
 219       (file-name-as-directory "/tmp"))))
 220
 221 ;; `make-temp-file' exists in Emacs only.  On XEmacs, we use our own
 222 ;; implementation with `make-temp-name', creating the temporary file
 223 ;; immediately in order to avoid a security hole.
 224 (defsubst tramp-compat-make-temp-file (filename &optional dir-flag)
 225   "Create a temporary file (compat function).
 226 Add the extension of FILENAME, if existing."
 227   (let* (file-name-handler-alist
 228          (prefix (expand-file-name
 229                   (symbol-value 'tramp-temp-name-prefix)
 230                   (tramp-compat-temporary-file-directory)))
 231          (extension (file-name-extension filename t))
 232          result)
 233     (condition-case nil
 234         (setq result
 235               (tramp-compat-funcall 'make-temp-file prefix dir-flag extension))
 236       (error
 237        ;; We use our own implementation, taken from files.el.
 238        (while
 239            (condition-case ()
 240                (progn
 241                  (setq result (concat (make-temp-name prefix) extension))
 242                  (if dir-flag
 243                      (make-directory result)
 244                    (write-region "" nil result nil 'silent))
 245                  nil)
 246              (file-already-exists t))
 247          ;; The file was somehow created by someone else between
 248          ;; `make-temp-name' and `write-region', let's try again.
 249          nil)))
 250     result))
 251
 252 ;; `most-positive-fixnum' does not exist in XEmacs.
 253 (defsubst tramp-compat-most-positive-fixnum ()
 254   "Return largest positive integer value (compat function)."
 255   (cond
 256    ((boundp 'most-positive-fixnum) (symbol-value 'most-positive-fixnum))
 257    ;; Default value in XEmacs.
 258    (t 134217727)))
 259
 260 (defun tramp-compat-decimal-to-octal (i)
 261   "Return a string consisting of the octal digits of I.
 262 Not actually used.  Use `(format \"%o\" i)' instead?"
 263   (cond ((< i 0) (error "Cannot convert negative number to octal"))
 264         ((not (integerp i)) (error "Cannot convert non-integer to octal"))
 265         ((zerop i) "0")
 266         (t (concat (tramp-compat-decimal-to-octal (/ i 8))
 267                    (number-to-string (% i 8))))))
 268
 269 ;; Kudos to Gerd Moellmann for this suggestion.
 270 (defun tramp-compat-octal-to-decimal (ostr)
 271   "Given a string of octal digits, return a decimal number."
 272   (let ((x (or ostr "")))
 273     ;; `save-match' is in `tramp-mode-string-to-int' which calls this.
 274     (unless (string-match "\\`[0-7]*\\'" x)
 275       (error "Non-octal junk in string `%s'" x))
 276     (string-to-number ostr 8)))
 277
 278 ;; ID-FORMAT does not exists in XEmacs.
 279 (defun tramp-compat-file-attributes (filename &optional id-format)
 280   "Like `file-attributes' for Tramp files (compat function)."
 281   (cond
 282    ((or (null id-format) (eq id-format 'integer))
 283     (file-attributes filename))
 284    ((tramp-tramp-file-p filename)
 285     (tramp-file-name-handler 'file-attributes filename id-format))
 286    (t (condition-case nil
 287           (tramp-compat-funcall 'file-attributes filename id-format)
 288         (wrong-number-of-arguments (file-attributes filename))))))
 289
 290 ;; PRESERVE-UID-GID does not exist in XEmacs.
 291 ;; PRESERVE-SELINUX-CONTEXT has been introduced with Emacs 24.1.
 292 (defun tramp-compat-copy-file
 293   (filename newname &optional ok-if-already-exists keep-date
 294             preserve-uid-gid preserve-selinux-context)
 295   "Like `copy-file' for Tramp files (compat function)."
 296   (cond
 297    (preserve-selinux-context
 298     (tramp-compat-funcall
 299      'copy-file filename newname ok-if-already-exists keep-date
 300      preserve-uid-gid preserve-selinux-context))
 301    (preserve-uid-gid
 302     (tramp-compat-funcall
 303      'copy-file filename newname ok-if-already-exists keep-date
 304      preserve-uid-gid))
 305    (t
 306     (copy-file filename newname ok-if-already-exists keep-date))))
 307
 308 ;; `copy-directory' is a new function in Emacs 23.2.  Implementation
 309 ;; is taken from there.
 310 (defun tramp-compat-copy-directory
 311   (directory newname &optional keep-time parents)
 312   "Make a copy of DIRECTORY (compat function)."
 313   (if (fboundp 'copy-directory)
 314       (tramp-compat-funcall 'copy-directory directory newname keep-time parents)
 315
 316     ;; If `default-directory' is a remote directory, make sure we find
 317     ;; its `copy-directory' handler.
 318     (let ((handler (or (find-file-name-handler directory 'copy-directory)
 319                        (find-file-name-handler newname 'copy-directory))))
 320       (if handler
 321           (funcall handler 'copy-directory directory newname keep-time parents)
 322
 323         ;; Compute target name.
 324         (setq directory (directory-file-name (expand-file-name directory))
 325               newname   (directory-file-name (expand-file-name newname)))
 326         (if (and (file-directory-p newname)
 327                  (not (string-equal (file-name-nondirectory directory)
 328                                     (file-name-nondirectory newname))))
 329             (setq newname
 330                   (expand-file-name
 331                    (file-name-nondirectory directory) newname)))
 332         (if (not (file-directory-p newname)) (make-directory newname parents))
 333
 334         ;; Copy recursively.
 335         (mapc
 336          (lambda (file)
 337            (if (file-directory-p file)
 338                (tramp-compat-copy-directory file newname keep-time parents)
 339              (copy-file file newname t keep-time)))
 340          ;; We do not want to delete "." and "..".
 341          (directory-files
 342           directory 'full "^\\([^.]\\|\\.\\([^.]\\|\\..\\)\\).*"))
 343
 344         ;; Set directory attributes.
 345         (set-file-modes newname (file-modes directory))
 346         (if keep-time
 347             (set-file-times newname (nth 5 (file-attributes directory))))))))
 348
 349 ;; TRASH has been introduced with Emacs 24.1.
 350 (defun tramp-compat-delete-file (filename &optional trash)
 351   "Like `delete-file' for Tramp files (compat function)."
 352   (condition-case nil
 353       (tramp-compat-funcall 'delete-file filename trash)
 354     ;; This Emacs version does not support the TRASH flag.
 355     (wrong-number-of-arguments
 356      (let ((delete-by-moving-to-trash
 357             (and (boundp 'delete-by-moving-to-trash)
 358                  (symbol-value 'delete-by-moving-to-trash)
 359                  trash)))
 360        (delete-file filename)))))
 361
 362 ;; RECURSIVE has been introduced with Emacs 23.2.
 363 (defun tramp-compat-delete-directory (directory &optional recursive)
 364   "Like `delete-directory' for Tramp files (compat function)."
 365   (if (null recursive)
 366       (delete-directory directory)
 367     (condition-case nil
 368         (tramp-compat-funcall 'delete-directory directory recursive)
 369       ;; This Emacs version does not support the RECURSIVE flag.  We
 370       ;; use the implementation from Emacs 23.2.
 371       (wrong-number-of-arguments
 372        (setq directory (directory-file-name (expand-file-name directory)))
 373        (if (not (file-symlink-p directory))
 374            (mapc (lambda (file)
 375                    (if (eq t (car (file-attributes file)))
 376                        (tramp-compat-delete-directory file recursive)
 377                      (delete-file file)))
 378                  (directory-files
 379                   directory 'full "^\\([^.]\\|\\.\\([^.]\\|\\..\\)\\).*")))
 380        (delete-directory directory)))))
 381
 382 ;; `number-sequence' does not exist in XEmacs.  Implementation is
 383 ;; taken from Emacs 23.
 384 (defun tramp-compat-number-sequence (from &optional to inc)
 385   "Return a sequence of numbers from FROM to TO as a list (compat function)."
 386   (if (or (subrp 'number-sequence) (symbol-file 'number-sequence))
 387       (tramp-compat-funcall 'number-sequence from to inc)
 388     (if (or (not to) (= from to))
 389         (list from)
 390       (or inc (setq inc 1))
 391       (when (zerop inc) (error "The increment can not be zero"))
 392       (let (seq (n 0) (next from))
 393         (if (> inc 0)
 394             (while (<= next to)
 395               (setq seq (cons next seq)
 396                     n (1+ n)
 397                     next (+ from (* n inc))))
 398           (while (>= next to)
 399             (setq seq (cons next seq)
 400                   n (1+ n)
 401                   next (+ from (* n inc)))))
 402         (nreverse seq)))))
 403
 404 (defun tramp-compat-split-string (string pattern)
 405   "Like `split-string' but omit empty strings.
 406 In Emacs, (split-string \"/foo/bar\" \"/\") returns (\"foo\" \"bar\").
 407 This is, the first, empty, element is omitted.  In XEmacs, the first
 408 element is not omitted."
 409   (delete "" (split-string string pattern)))
 410
 411 (defun tramp-compat-call-process
 412   (program &optional infile destination display &rest args)
 413   "Calls `call-process' on the local host.
 414 This is needed because for some Emacs flavors Tramp has
 415 defadvised `call-process' to behave like `process-file'.  The
 416 Lisp error raised when PROGRAM is nil is trapped also, returning 1."
 417   (let ((default-directory
 418           (if (file-remote-p default-directory)
 419               (tramp-compat-temporary-file-directory)
 420             default-directory)))
 421     (if (executable-find program)
 422         (apply 'call-process program infile destination display args)
 423       1)))
 424
 425 (defun tramp-compat-process-running-p (process-name)
 426   "Returns `t' if system process PROCESS-NAME is running for `user-login-name'."
 427   (when (stringp process-name)
 428     (cond
 429      ;; GNU Emacs 22 on w32.
 430      ((fboundp 'w32-window-exists-p)
 431       (tramp-compat-funcall 'w32-window-exists-p process-name process-name))
 432
 433      ;; GNU Emacs 23.
 434      ((and (fboundp 'list-system-processes) (fboundp 'process-attributes))
 435       (let (result)
 436         (dolist (pid (tramp-compat-funcall 'list-system-processes) result)
 437           (let ((attributes (tramp-compat-funcall 'process-attributes pid)))
 438             (when (and (string-equal
 439                         (cdr (assoc 'user attributes)) (user-login-name))
 440                        (let ((comm (cdr (assoc 'comm attributes))))
 441                          ;; The returned command name could be truncated
 442                          ;; to 15 characters.  Therefore, we cannot check
 443                          ;; for `string-equal'.
 444                          (and comm (string-match
 445                                     (concat "^" (regexp-quote comm))
 446                                     process-name))))
 447               (setq result t))))))
 448
 449      ;; Fallback, if there is no Lisp support yet.
 450      (t (let ((default-directory
 451                 (if (file-remote-p default-directory)
 452                     (tramp-compat-temporary-file-directory)
 453                   default-directory))
 454               (unix95 (getenv "UNIX95"))
 455               result)
 456           (setenv "UNIX95" "1")
 457           (when (member
 458                  (user-login-name)
 459                  (tramp-compat-split-string
 460                   (shell-command-to-string
 461                    (format "ps -C %s -o user=" process-name))
 462                   "[ \f\t\n\r\v]+"))
 463             (setq result t))
 464           (setenv "UNIX95" unix95)
 465           result)))))
 466
 467 ;; The following functions do not exist in XEmacs.  We ignore this;
 468 ;; they are used for checking a remote tty.
 469 (defun tramp-compat-process-get (process propname)
 470   "Return the value of PROCESS' PROPNAME property.
 471 This is the last value stored with `(process-put PROCESS PROPNAME VALUE)'."
 472   (ignore-errors (tramp-compat-funcall 'process-get process propname)))
 473
 474 (defun tramp-compat-process-put (process propname value)
 475   "Change PROCESS' PROPNAME property to VALUE.
 476 It can be retrieved with `(process-get PROCESS PROPNAME)'."
 477   (ignore-errors (tramp-compat-funcall 'process-put process propname value)))
 478
 479 (defun tramp-compat-set-process-query-on-exit-flag (process flag)
 480   "Specify if query is needed for process when Emacs is exited.
 481 If the second argument flag is non-nil, Emacs will query the user before
 482 exiting if process is running."
 483   (if (fboundp 'set-process-query-on-exit-flag)
 484       (tramp-compat-funcall 'set-process-query-on-exit-flag process flag)
 485     (tramp-compat-funcall 'process-kill-without-query process flag)))
 486
 487 ;; There exist different implementations for this function.
 488 (defun tramp-compat-coding-system-change-eol-conversion (coding-system eol-type)
 489   "Return a coding system like CODING-SYSTEM but with given EOL-TYPE.
 490 EOL-TYPE can be one of `dos', `unix', or `mac'."
 491   (cond ((fboundp 'coding-system-change-eol-conversion)
 492          (tramp-compat-funcall
 493           'coding-system-change-eol-conversion coding-system eol-type))
 494         ((fboundp 'subsidiary-coding-system)
 495          (tramp-compat-funcall
 496           'subsidiary-coding-system coding-system
 497           (cond ((eq eol-type 'dos) 'crlf)
 498                 ((eq eol-type 'unix) 'lf)
 499                 ((eq eol-type 'mac) 'cr)
 500                 (t
 501                  (error "Unknown EOL-TYPE `%s', must be %s"
 502                         eol-type
 503                         "`dos', `unix', or `mac'")))))
 504         (t (error "Can't change EOL conversion -- is MULE missing?"))))
 505
 506 (add-hook 'tramp-unload-hook
 507           (lambda ()
 508             (unload-feature 'tramp-compat 'force)))
 509
 510 (provide 'tramp-compat)
 511
 512 ;;; TODO:
 513
 514 ;;; tramp-compat.el ends here