lisp/eshell/esh-ext.el

   1 ;;; esh-ext.el --- commands external to Eshell
   2
   3 ;; Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006, 2007, 2008 Free Software Foundation, Inc.
   5
   6 ;; Author: John Wiegley <johnw@gnu.org>
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; To force a command to invoked external, either provide an explicit
  26 ;; pathname for the command argument, or prefix the command name with
  27 ;; an asterix character.  Example:
  28 ;;
  29 ;;   grep        ; make invoke `grep' Lisp function, or `eshell/grep'
  30 ;;   /bin/grep   ; will definitely invoke /bin/grep
  31 ;;   *grep        ; will also invoke /bin/grep
  32
  33 (provide 'esh-ext)
  34
  35 (eval-when-compile
  36   (require 'esh-cmd))
  37 (require 'esh-util)
  38
  39 (defgroup eshell-ext nil
  40   "External commands are invoked when operating system executables are
  41 loaded into memory, thus beginning a new process."
  42   :tag "External commands"
  43   :group 'eshell)
  44
  45 ;;; User Variables:
  46
  47 (defcustom eshell-ext-load-hook '(eshell-ext-initialize)
  48   "*A hook that gets run when `eshell-ext' is loaded."
  49   :type 'hook
  50   :group 'eshell-ext)
  51
  52 (defcustom eshell-binary-suffixes exec-suffixes
  53   "*A list of suffixes used when searching for executable files."
  54   :type '(repeat string)
  55   :group 'eshell-ext)
  56
  57 (defcustom eshell-force-execution nil
  58   "*If non-nil, try to execute binary files regardless of permissions.
  59 This can be useful on systems like Windows, where the operating system
  60 doesn't happen to honor the permission bits in certain cases; or in
  61 cases where you want to associate an interpreter with a particular
  62 kind of script file, but the language won't let you but a '#!'
  63 interpreter line in the file, and you don't want to make it executable
  64 since nothing else but Eshell will be able to understand
  65 `eshell-interpreter-alist'."
  66   :type 'boolean
  67   :group 'eshell-ext)
  68
  69 (defun eshell-search-path (name)
  70   "Search the environment path for NAME."
  71   (if (file-name-absolute-p name)
  72       name
  73     (let ((list (parse-colon-path (getenv "PATH")))
  74           suffixes n1 n2 file)
  75       (while list
  76         (setq n1 (concat (car list) name))
  77         (setq suffixes eshell-binary-suffixes)
  78         (while suffixes
  79           (setq n2 (concat n1 (car suffixes)))
  80           (if (and (or (file-executable-p n2)
  81                        (and eshell-force-execution
  82                             (file-readable-p n2)))
  83                    (not (file-directory-p n2)))
  84               (setq file n2 suffixes nil list nil))
  85           (setq suffixes (cdr suffixes)))
  86         (setq list (cdr list)))
  87       file)))
  88
  89 (defcustom eshell-windows-shell-file
  90   (if (eshell-under-windows-p)
  91       (if (string-match "\\(\\`cmdproxy\\|sh\\)\\.\\(com\\|exe\\)"
  92                         shell-file-name)
  93           (or (eshell-search-path "cmd.exe")
  94               (eshell-search-path "command.com"))
  95         shell-file-name))
  96   "*The name of the shell command to use for DOS/Windows batch files.
  97 This defaults to nil on non-Windows systems, where this variable is
  98 wholly ignored."
  99   :type '(choice file (const nil))
 100   :group 'eshell-ext)
 101
 102 (defsubst eshell-invoke-batch-file (&rest args)
 103   "Invoke a .BAT or .CMD file on DOS/Windows systems."
 104   ;; since CMD.EXE can't handle forward slashes in the initial
 105   ;; argument...
 106   (setcar args (subst-char-in-string ?/ ?\\ (car args)))
 107   (throw 'eshell-replace-command
 108          (eshell-parse-command eshell-windows-shell-file (cons "/c" args))))
 109
 110 (defcustom eshell-interpreter-alist
 111   (if (eshell-under-windows-p)
 112       '(("\\.\\(bat\\|cmd\\)\\'" . eshell-invoke-batch-file)))
 113   "*An alist defining interpreter substitutions.
 114 Each member is a cons cell of the form:
 115
 116   (MATCH . INTERPRETER)
 117
 118 MATCH should be a regexp, which is matched against the command name,
 119 or a function.  If either returns a non-nil value, then INTERPRETER
 120 will be used for that command.
 121
 122 If INTERPRETER is a string, it will be called as the command name,
 123 with the original command name passed as the first argument, with all
 124 subsequent arguments following.  If INTERPRETER is a function, it will
 125 be called with all of those arguments.  Note that interpreter
 126 functions should throw `eshell-replace-command' with the alternate
 127 command form, or they should return a value compatible with the
 128 possible return values of `eshell-external-command', which see."
 129   :type '(repeat (cons (choice regexp (function :tag "Predicate"))
 130                        (choice string (function :tag "Interpreter"))))
 131   :group 'eshell-ext)
 132
 133 (defcustom eshell-alternate-command-hook nil
 134   "*A hook run whenever external command lookup fails.
 135 If a functions wishes to provide an alternate command, they must throw
 136 it using the tag `eshell-replace-command'.  This is done because the
 137 substituted command need not be external at all, and therefore must be
 138 passed up to a higher level for re-evaluation.
 139
 140 Or, if the function returns a filename, that filename will be invoked
 141 with the current command arguments rather than the command specified
 142 by the user on the command line."
 143   :type 'hook
 144   :group 'eshell-ext)
 145
 146 (defcustom eshell-command-interpreter-max-length 256
 147   "*The maximum length of any command interpreter string, plus args."
 148   :type 'integer
 149   :group 'eshell-ext)
 150
 151 (defcustom eshell-explicit-command-char ?*
 152   "*If this char occurs before a command name, call it externally.
 153 That is, although `vi' may be an alias, `\vi' will always call the
 154 external version."
 155   :type 'character
 156   :group 'eshell-ext)
 157
 158 ;;; Functions:
 159
 160 (defun eshell-ext-initialize ()
 161   "Initialize the external command handling code."
 162   (add-hook 'eshell-named-command-hook 'eshell-explicit-command nil t))
 163
 164 (defun eshell-explicit-command (command args)
 165   "If a command name begins with `*', call it externally always.
 166 This bypasses all Lisp functions and aliases."
 167   (when (and (> (length command) 1)
 168              (eq (aref command 0) eshell-explicit-command-char))
 169     (let ((cmd (eshell-search-path (substring command 1))))
 170       (if cmd
 171           (or (eshell-external-command cmd args)
 172               (error "%s: external command failed" cmd))
 173         (error "%s: external command not found"
 174                (substring command 1))))))
 175
 176 (defun eshell-remote-command (handler command args)
 177   "Insert output from a remote COMMAND, using ARGS.
 178 A remote command is something that executes on a different machine.
 179 An external command simply means external to Emacs.
 180
 181 Note that this function is very crude at the moment.  It gathers up
 182 all the output from the remote command, and sends it all at once,
 183 causing the user to wonder if anything's really going on..."
 184   (let ((outbuf (generate-new-buffer " *eshell remote output*"))
 185         (errbuf (generate-new-buffer " *eshell remote error*"))
 186         (exitcode 1))
 187     (unwind-protect
 188         (progn
 189           (setq exitcode
 190                 (funcall handler 'shell-command
 191                          (mapconcat 'shell-quote-argument
 192                                     (append (list command) args) " ")
 193                          outbuf errbuf))
 194           (eshell-print (save-excursion (set-buffer outbuf)
 195                                         (buffer-string)))
 196           (eshell-error (save-excursion (set-buffer errbuf)
 197                                         (buffer-string))))
 198       (eshell-close-handles exitcode 'nil)
 199       (kill-buffer outbuf)
 200       (kill-buffer errbuf))))
 201
 202 (defun eshell-external-command (command args)
 203   "Insert output from an external COMMAND, using ARGS."
 204   (setq args (eshell-stringify-list (eshell-flatten-list args)))
 205   (let ((handler
 206          (unless (or (equal default-directory "/")
 207                      (and (eshell-under-windows-p)
 208                           (string-match "\\`[A-Za-z]:[/\\\\]\\'"
 209                                         default-directory)))
 210            (find-file-name-handler default-directory
 211                                    'shell-command))))
 212     (if (and handler
 213              (not (and (featurep 'xemacs)
 214                        (eq handler 'dired-handler-fn))))
 215         (eshell-remote-command handler command args))
 216     (let ((interp (eshell-find-interpreter command)))
 217       (assert interp)
 218       (if (functionp (car interp))
 219           (apply (car interp) (append (cdr interp) args))
 220         (eshell-gather-process-output
 221          (car interp) (append (cdr interp) args))))))
 222
 223 (defun eshell/addpath (&rest args)
 224   "Add a set of paths to PATH."
 225   (eshell-eval-using-options
 226    "addpath" args
 227    '((?b "begin" nil prepend "add path element at beginning")
 228      (?h "help" nil nil  "display this usage message")
 229      :usage "[-b] PATH
 230 Adds the given PATH to $PATH.")
 231    (if args
 232        (progn
 233          (if prepend
 234              (setq args (nreverse args)))
 235          (while args
 236            (setenv "PATH"
 237                    (if prepend
 238                        (concat (car args) path-separator
 239                                (getenv "PATH"))
 240                      (concat (getenv "PATH") path-separator
 241                              (car args))))
 242            (setq args (cdr args))))
 243      (let ((paths (parse-colon-path (getenv "PATH"))))
 244        (while paths
 245          (eshell-printn (car paths))
 246          (setq paths (cdr paths)))))))
 247
 248 (put 'eshell/addpath 'eshell-no-numeric-conversions t)
 249
 250 (defun eshell-script-interpreter (file)
 251   "Extract the script to run from FILE, if it has #!<interp> in it.
 252 Return nil, or a list of the form:
 253
 254   (INTERPRETER [ARGS] FILE)"
 255   (let ((maxlen eshell-command-interpreter-max-length))
 256     (if (and (file-readable-p file)
 257              (file-regular-p file))
 258         (with-temp-buffer
 259           (insert-file-contents-literally file nil 0 maxlen)
 260           (if (looking-at "#![ \t]*\\([^ \r\t\n]+\\)\\([ \t]+\\(.+\\)\\)?")
 261               (if (match-string 3)
 262                   (list (match-string 1)
 263                         (match-string 3)
 264                         file)
 265                 (list (match-string 1)
 266                       file)))))))
 267
 268 (defun eshell-find-interpreter (file &optional no-examine-p)
 269   "Find the command interpreter with which to execute FILE.
 270 If NO-EXAMINE-P is non-nil, FILE will not be inspected for a script
 271 line of the form #!<interp>."
 272   (let ((finterp
 273          (catch 'found
 274            (ignore
 275             (eshell-for possible eshell-interpreter-alist
 276               (cond
 277                ((functionp (car possible))
 278                 (and (funcall (car possible) file)
 279                      (throw 'found (cdr possible))))
 280                ((stringp (car possible))
 281                 (and (string-match (car possible) file)
 282                      (throw 'found (cdr possible))))
 283                (t
 284                 (error "Invalid interpreter-alist test"))))))))
 285     (if finterp                         ; first check
 286         (list finterp file)
 287       (let ((fullname (if (file-name-directory file) file
 288                         (eshell-search-path file)))
 289             (suffixes eshell-binary-suffixes))
 290         (if (and fullname (not (or eshell-force-execution
 291                                    (file-executable-p fullname))))
 292             (while suffixes
 293               (let ((try (concat fullname (car suffixes))))
 294                 (if (or (file-executable-p try)
 295                         (and eshell-force-execution
 296                              (file-readable-p try)))
 297                     (setq fullname try suffixes nil)
 298                   (setq suffixes (cdr suffixes))))))
 299         (cond ((not (and fullname (file-exists-p fullname)))
 300                (let ((name (or fullname file)))
 301                  (unless (setq fullname
 302                                (run-hook-with-args-until-success
 303                                 'eshell-alternate-command-hook file))
 304                    (error "%s: command not found" name))))
 305               ((not (or eshell-force-execution
 306                         (file-executable-p fullname)))
 307                (error "%s: Permission denied" fullname)))
 308         (let (interp)
 309           (unless no-examine-p
 310             (setq interp (eshell-script-interpreter fullname))
 311             (if interp
 312                 (setq interp
 313                       (cons (car (eshell-find-interpreter (car interp) t))
 314                             (cdr interp)))))
 315           (or interp (list fullname)))))))
 316
 317 ;;; Code:
 318
 319 ;; arch-tag: 178d4064-7e60-4745-b81f-bab5d8d7c40f
 320 ;;; esh-ext.el ends here