Re: smtpmail on Windows native Emacs with gnutls-cli from Cygwin freeze.

[Oleksandr Gavenko <gavenkoa@gmail.com>]

24.10.2011 0:53, Oleksandr Gavenko пишет:
> I like use native Emacs with Cygwin toolset. It does not
> hard to friend then. But from time to time I discover some issues.
>
> Now time I finally try setup Emacs to work with mail.
>
> GMail SMTP require TLS connection. As usual this done by
> 'gnus/starttls.el'.
>
> After configuring smtpmail (send-mail-function==smtpmail-send-it)
> I try compose mail:
>
> C-x m bla-bla-bla C-c C-c
>
> Emacs freeze! Try same in Cygwin Emacs and all OK!
>
> After debug I found root of evil:
>
> (defun starttls-open-stream-gnutls (name buffer host port)
> ...
> (process (apply #'start-process name buffer
> starttls-gnutls-program "-s" host
> "-p" (if (integerp port)
> (int-to-string port)
> port)
> starttls-extra-arguments))
> ...)))))
>
> (defun starttls-negotiate-gnutls (process)
> ...
> ;; XXX How to remove/extract the TLS negotiation junk?
> (signal-process (process-id process) 'SIGALRM)
> ...
> (save-excursion
> (setq old-max (goto-char (point-max)))
> (signal-process (process-id process) 'SIGALRM)
> (while (and (processp process)
> (eq (process-status process) 'run)
> (save-excursion
> (goto-char old-max)
> (not (or (setq done-ok (re-search-forward
> starttls-success nil t))
> (setq done-bad (re-search-forward
> starttls-failure nil t))))))
> (accept-process-output process 1 100)
> (sit-for 0.1))
> ...
>
> So 'gnutls-cli' called with '-s' option. From man page:
>
> -s, --starttls
> Connect, establish a plain session and start TLS
> when EOF or a SIGALRM is received.
>
> and 'signal-process' call do nothing for SIGALRM. More correctly
> return error. Look to 'src/w32proc.c':
>
> int
> sys_kill (int pid, int sig)
> {
> ...
> /* Only handle signals that will result in the process dying */
> if (sig != SIGINT && sig != SIGKILL && sig != SIGQUIT && sig != SIGHUP)
> {
> errno = EINVAL;
> return -1;
> }
>
> So 'gnutls-cli' don't send anything and 'while' loop can not match
> 'starttls-failure', 'starttls-success', etc...
>
> I easy make workaround. Just replace 'signal-process' with Cygwin
> 'kill.exe':
>
> (shell-command (format "kill.exe -s SIGALRM %d" (process-id process)))
>
Solution that prevent modify any existing lisp code:

(defadvice signal-process (around cygwin (process sigcode))
   "Use 'kill.exe' instead build-in Emacs 'kill'."
   (if (eq sigcode 'SIGALRM)
       (shell-command
        (format "kill.exe -s SIGALRM %d"
                (if (processp process) (process-id process) process)))
     ad-do-it
     ))
(ad-activate 'signal-process)

-- 
Happy hacking!