GNU bug report logs - #472
pgg-gpg.el - pgg-gpg-process-region timing problem

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Message #5 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: "ken manheimer" <ken.manheimer <at> gmail.com>
To: "Thien-Thi Nguyen" <ttn <at> gnuvola.org>
Cc: wilde <at> sha-bang.de, emacs-pretest-bug <at> gnu.org, ueno <at> unixuser.org,
        emacs-devel <emacs-devel <at> gnu.org>
Subject: Re: pgg-gpg.el - pgg-gpg-process-region timing problem
Date: Mon, 23 Jun 2008 13:44:52 -0400

hi, thi.  thanks for the responses - i'm glad to see investigation into this.

i've tried both the patches, and both hang for me on the pggprob.el
test.  the hang is interruptable with Ctl-G keyboard quit.  i tried
stepping through the second patched version with edebug (including
disabling the '(inhibit-redisplay t)' let-binding, which thwarts
edebug stepping), and found the hang happens at the first
'(accept-process-output process)'.  (it hangs at the second one if i
don't provide a passphrase.)

i'm not sure what's happening.  in case it helps, gpg 1.4.6 is what's
running on my system.
-- 
ken
http://myriadicity.net



On Mon, Jun 23, 2008 at 9:17 AM, Thien-Thi Nguyen <ttn <at> gnuvola.org> wrote:
> Delving into this, i got a little carried away... full func below.
> This adds GOOD_PASSPHRASE checking (necessary for GNUPG 1.4.6, at
> least) and some other coding-system related finessing, but removes
> the sentinel proposed in the first attempt.  In its place, we zonk
> the baleful `process-adaptive-read-buffering' and remove timeout
> parameters from `accept-process-output' calls.
>
> With this func things seem to work fine for `pgg-sign' on a small
> buffer, and mostly for large buffers (270KB), but sometimes (~10%)
> with large buffers, i see a "file error: bad address *GnuPG*".  Hmmm...
>
> thi
>
> ______________________________________________________________________
> (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"))
>         (args
>          `("--status-fd" "2"
>            ,@(if use-agent '("--use-agent")
>                (if passphrase '("--passphrase-fd" "0")))
>            "--yes" ; overwrite
>            "--output" ,output-file-name
>            ,@pgg-gpg-extra-args ,@args))
>         (output-buffer pgg-output-buffer)
>         (errors-buffer pgg-errors-buffer)
>         (orig-mode (default-file-modes))
>         (inhibit-redisplay t))
>    (with-current-buffer (get-buffer-create errors-buffer)
>      (buffer-disable-undo)
>      (erase-buffer))
>    (unwind-protect
>        (let* ((coding-system-for-write 'binary)
>               ;; GNUPG 1.4.6 does not terminate on bad passphrase, eg:
>               ;;   [GNUPG:] BAD_PASSPHRASE (long hex # here)
>               ;;   gpg: skipped "ttn": bad passphrase
>               ;;   gpg: [stdin]: clearsign failed: bad passphrase
>               ;; so we need to check that condition ourselves and bail out.
>               ;;
>               ;; To check if the passphrase is accepted, we need to parse the
>               ;; errors-buffer, but `process-adaptive-read-buffering' non-nil
>               ;; sometimes prevents it from filling.  So turn it off.
>               (process-adaptive-read-buffering (not passphrase))
>               (process (progn
>                          (set-default-file-modes 448)
>                          (apply #'start-process "*GnuPG*"
>                                 errors-buffer program args)))
>               (status (process-status process))
>
>               exit-status)
>          (set-process-sentinel process nil)
>          (when passphrase
>            (let ((coding-system-for-write (or pgg-passphrase-coding-system
>                                               'binary)))
>              (process-send-string process passphrase))
>            (process-send-string process "\n")
>            ;; Bail out if passphrase is not accepted.
>            ;; MAINTAIN ME: Tested against GNUPG 1.4.6.
>            (let (result)
>              (while (not result)
>                (accept-process-output process)
>                (with-current-buffer errors-buffer
>                  (save-excursion
>                    (goto-char (point-min))
>                    (when (re-search-forward
>                           ;; BGM: BAD, GOOD, MISSING.
>                           "^.GNUPG:. \\([BGM][A-Z]+\\)_PASSPHRASE"
>                           nil t)
>                      (setq result (match-string 1))))))
>              (unless (string= "GOOD" result)
>                (error "Passphrase no good"))))
>          (process-send-region process start end)
>          (process-send-eof process)
>          ;; TODO: Re-enable `process-adaptive-read-buffering' here.
>          (while (eq 'run (setq status (process-status process)))
>            (accept-process-output process))
>          (delete-process process)
>          (setq exit-status (process-exit-status process))
>          (with-current-buffer (get-buffer-create output-buffer)
>            (buffer-disable-undo)
>            (erase-buffer)
>            (if (file-exists-p output-file-name)
>                (let ((coding-system-for-read (if pgg-text-mode
>                                                  'raw-text
>                                                'binary)))
>                  (insert-file-contents output-file-name)))
>            (set-buffer errors-buffer)
>            (if (memq status '(stop signal))
>                (error "%s exited abnormally: '%s'" program exit-status))
>            (if (= 127 exit-status)
>                (error "%s could not be found" program))))
>      (if (file-exists-p output-file-name)
>          (delete-file output-file-name))
>      (when (get-process "*GnuPG*")
>        (kill-process "*GnuPG*"))
>      (set-default-file-modes orig-mode))))

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