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

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

[Oleksandr Gavenko]

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)))

Conclusion from this story: check return codes... and don't use
unsupported configuration!

But I think Emacs 'gnus/starttls.el' code can be rewritten to be able
work with Cygwin gnutls-cli without signals...

As emacs-jabber package work fine with Cygwin! I successfully use
it for 2 years with Google GTalk over TLS...

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

[Oleksandr Gavenko]

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!

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

[Lars Magne Ingebrigtsen]

Oleksandr Gavenko <gavenkoa@gmail.com> writes:


[...]

> 	  (signal-process (process-id process) 'SIGALRM)

[...]

> 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;
>       }

Isn't that the bug, though?  Why isn't `signal-process' sending the
signal we request on Windows?

-- 
(domestic pets only, the antidote for overdose, milk.)
  bloggy blog http://lars.ingebrigtsen.no/

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

[Eli Zaretskii]

> From: Lars Magne Ingebrigtsen <larsi@gnus.org>
> Date: Mon, 24 Oct 2011 01:56:34 +0200
> MailScanner-NULL-Check: 1320019000.28138@KSiCUCFVgPG6ekyuuDsfeQ
> Cc: emacs-devel@gnu.org
> 
> Oleksandr Gavenko <gavenkoa@gmail.com> writes:
> 
> 
> [...]
> 
> > 	  (signal-process (process-id process) 'SIGALRM)
> 
> [...]
> 
> > 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;
> >       }
> 
> Isn't that the bug, though?  Why isn't `signal-process' sending the
> signal we request on Windows?

Because you cannot send a signal to another process on MS-Windows.

Look at the rest of the code in sys_kill, below the above test, and
you will see that it emulates sending the 4 signals mentioned above,
by either (a) sending the equivalent of Ctrl-C to the window of the
sub-process, or (b) by forcefully terminating that process.

Emulating SIGALRM in a similar way is extremely tricky, because it
would involve reading the other process's memory to find out where its
SIGALRM handler is, if any (very non-trivial), and either terminating
it if no handler is found (easy) or calling that handler (hard).
Patches to do that are welcome.

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

[Eli Zaretskii]

> From: Oleksandr Gavenko <gavenkoa@gmail.com>
> Date: Mon, 24 Oct 2011 00:53:12 +0300
> 
> 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!

Was your native Windows build of Emacs built with GnuTLS support?
See the section in nt/INSTALL about "Optional GnuTLS support", for
the details.  I understand that if you build Emacs with GnuTLS support
and install the GnuTLS binaries from the URL in that section, you will
have gnutls in the native Emacs without any need for the Cygwin gnutls
executable, and without any need to hack Emacs for SIGALRM.

If the GnuTLS configuration described in nt/INSTALL doesn't work,
please submit a bug report.  I'm quite sure several people use that
configuration successfully.

> Conclusion from this story: check return codes... and don't use
> unsupported configuration!

The latter.  Especially if the supported configuration already has
GnuTLS support built into it.

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

[Oleksandr Gavenko]

24.10.2011 10:15, Eli Zaretskii пишет:
> Was your native Windows build of Emacs built with GnuTLS support?
> See the section in nt/INSTALL about "Optional GnuTLS support", for
> the details.  I understand that if you build Emacs with GnuTLS support
> and install the GnuTLS binaries from the URL in that section, you will
> have gnutls in the native Emacs without any need for the Cygwin gnutls
> executable, and without any need to hack Emacs for SIGALRM.
>
According to bzr log:

   revno: 104106
   committer: Juanma Barranquero <lekktu@gmail.com>
   branch nick: trunk
   timestamp: Wed 2011-05-04 16:03:16 +0200
   message:
     Implement dynamic loading of GnuTLS on Windows.

   revno: 104262
   committer: Eli Zaretskii <eliz@gnu.org>
   branch nick: trunk
   timestamp: Tue 2011-05-17 21:17:45 +0300
   message:
     nt/README.W32: Add information about GnuTLS libraries.

So support for GnuTLS on Windows recently appear...

I always use official build of Emacs from
ftp://ftp.gnu.org/gnu/emacs/windows/ so have no GnuTLS in
emacs.exe...

Are there any recommended way to get latest or pretest/RC Emacs build?

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

[Eli Zaretskii]

> From: Oleksandr Gavenko <gavenkoa@gmail.com>
> Date: Mon, 24 Oct 2011 23:21:49 +0300
> 
> Are there any recommended way to get latest or pretest/RC Emacs build?

You can find the pretest zip files here:

  ftp://alpha.gnu.org/gnu/emacs/pretest/windows/

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

[l1dge]

Thanks for this tip, I've been looking for a solution all evening and have
finally got gnus to work within emacs!

Cheers
Lee



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