Re: Fix needed for communication with gpg-agent

[Chong Yidong <cyd@stupidchicken.com>]

> Another solution might be to cannibalize the ansi-term code, and have
> the pinentry program run in an elisp terminal.  I looked into this,
> and concluded that it is a big job.  It should be left till after the
> release.

FWIW, here is a patch that implements the idea I outlined above.  I
have tested it, and it works with the curses version of pinentry.

Admittedly, it is a rather naughty solution: GPG is called through an
elisp terminal (as implemented by `make-term' in term.el), with a
modified process filter whose purpose is to send GPG the string to be
encrypted when required.  The terminal is run in a recursive editing
level, so that the user can input to pinentry if necessary; the
process sentinel is modified to call `exit-recursive-edit' when GPG
exits, to return control to pgg-gpg-process-region.

*** emacs/lisp/pgg-gpg.el.~1.22.~	2007-02-18 11:07:52.000000000 -0500
--- emacs/lisp/pgg-gpg.el	2007-02-22 12:23:11.000000000 -0500
***************
*** 60,65 ****
--- 60,67 ----
  (defvar pgg-gpg-user-id nil
    "GnuPG ID of your default identity.")
  
+ (defvar pgg-gpg-term-input nil)
+ 
  (defun pgg-gpg-process-region (start end passphrase program args)
    (let* ((use-agent (and (null passphrase) (pgg-gpg-use-agent-p)))
  	 (output-file-name (pgg-make-temp-file "pgg-output"))
***************
*** 83,114 ****
        (erase-buffer))
      (unwind-protect
  	(progn
! 	  (set-default-file-modes 448)
! 	  (let ((coding-system-for-write 'binary))
! 	    (setq process
! 		  (apply #'start-process "*GnuPG*" errors-buffer
! 			 program args)))
! 	  (set-process-sentinel process #'ignore)
! 	  (when passphrase
! 	    (setq passphrase-with-newline (concat passphrase "\n"))
! 	    (if pgg-passphrase-coding-system
! 		(progn
! 		  (setq encoded-passphrase-with-new-line
! 			(encode-coding-string
! 			 passphrase-with-newline
! 			 (coding-system-change-eol-conversion
! 			  pgg-passphrase-coding-system 'unix)))
! 		  (pgg-clear-string passphrase-with-newline))
! 	      (setq encoded-passphrase-with-new-line passphrase-with-newline
! 		    passphrase-with-newline nil))
! 	    (process-send-string process encoded-passphrase-with-new-line))
! 	  (process-send-region process start end)
! 	  (process-send-eof process)
! 	  (while (eq 'run (process-status process))
! 	    (accept-process-output process 5))
! 	  (setq status (process-status process)
! 		exit-status (process-exit-status process))
! 	  (delete-process process)
  	  (with-current-buffer (get-buffer-create output-buffer)
  	    (buffer-disable-undo)
  	    (erase-buffer)
--- 85,130 ----
        (erase-buffer))
      (unwind-protect
  	(progn
! 	  (if (and (not window-system) use-agent)
! 	      (let ((term-term-name "vt100")
! 		    (buf (current-buffer)))
! 		(apply #'make-term "GPGTERM" "gpg" nil args)
! 		(switch-to-buffer "*GPGTERM*")
! 		(set (make-local-variable 'pgg-gpg-term-input)
! 		     (list buf start end))
! 		(setq process (get-buffer-process "*GPGTERM*"))
! 		(term-char-mode)
! 		(set-process-filter process 'pgg-gpg-filter)
! 		(set-process-sentinel process 'pgg-gpg-sentinel)
! 		(recursive-edit)
! 		(setq exit-status (process-exit-status process)))
! 	    (set-default-file-modes 448)
! 	    (let ((coding-system-for-write 'binary))
! 	      (setq process
! 		    (apply #'start-process "*GnuPG*" errors-buffer
! 			   program args)))
! 	    (set-process-sentinel process #'ignore)
! 	    (accept-process-output process nil nil 1)
! 	    (when passphrase
! 	      (setq passphrase-with-newline (concat passphrase "\n"))
! 	      (if pgg-passphrase-coding-system
! 		  (progn
! 		    (setq encoded-passphrase-with-new-line
! 			  (encode-coding-string
! 			   passphrase-with-newline
! 			   (coding-system-change-eol-conversion
! 			    pgg-passphrase-coding-system 'unix)))
! 		    (pgg-clear-string passphrase-with-newline))
! 		(setq encoded-passphrase-with-new-line passphrase-with-newline
! 		      passphrase-with-newline nil))
! 	      (process-send-string process encoded-passphrase-with-new-line))
! 	    (process-send-region process start end)
! 	    (process-send-eof process)
! 	    (while (eq 'run (process-status process))
! 	      (accept-process-output process 5))
! 	    (setq status (process-status process)
! 		  exit-status (process-exit-status process))
! 	    (delete-process process))
  	  (with-current-buffer (get-buffer-create output-buffer)
  	    (buffer-disable-undo)
  	    (erase-buffer)
***************
*** 132,137 ****
--- 148,174 ----
  	  (delete-file output-file-name))
        (set-default-file-modes orig-mode))))
  
+ (defun pgg-gpg-filter (proc str)
+   (if (and (string-match "writing to" str) pgg-gpg-term-input)
+       (let ((buf   (nth 0 pgg-gpg-term-input))
+ 	    (start (nth 1 pgg-gpg-term-input))
+ 	    (end   (nth 2 pgg-gpg-term-input)))
+ 	(erase-buffer)
+ 	(with-current-buffer buf
+ 	  (process-send-region proc start end)
+ 	  (process-send-eof proc)
+ 	  (process-send-eof proc)
+ 	  (setq pgg-gpg-filter-args nil)))
+     (term-emulate-terminal proc str)))
+ 
+ (defun pgg-gpg-sentinel (proc msg)
+   (let ((buffer (process-buffer proc)))
+     (when (memq (process-status proc) '(signal exit))
+       (delete-process proc)
+       (unless (null (buffer-name buffer))
+ 	(kill-buffer buffer))
+       (exit-recursive-edit))))
+ 
  (defun pgg-gpg-possibly-cache-passphrase (passphrase &optional key notruncate)
    (if (and passphrase
  	   pgg-cache-passphrase