Re: url-retrieve-synchronously randomly fails on https URLs (patch included)

["Riccardo Murri" <riccardo.murri@gmail.com>]

On 10/30/07, Richard Stallman <rms@gnu.org> wrote:
> Would you please post a change log for the patch?
> Then it will be installed.
>

Draft changelog for the appended patch:

* (tls-end-of-info): New customization option (regexp).
* (open-tls-stream): Accept input until `tls-end-of-info' is matched.


-- 
Riccardo Murri, via Galeazzo Alessi 61, 00176 Roma


--- src/emacs22/lisp/net/tls.el 2007-08-05 21:06:12.000000000 +0200
+++ emacs/lisp/tls.el   2007-10-29 19:17:33.000000000 +0100
@@ -51,6 +51,9 @@
   (autoload 'format-spec "format-spec")
   (autoload 'format-spec-make "format-spec"))

+(eval-when-compile
+  (require 'rx))  ; for writing readable regexps
+
 (defgroup tls nil
   "Transport Layer Security (TLS) parameters."
   :group 'comm)
@@ -89,6 +92,40 @@
   :type 'string
   :group 'tls)

+(defcustom tls-end-of-info
+ (rx
+  (or
+   ;; `openssl s_client` regexp
+   (sequence
+    ;; see ssl/ssl_txt.c lines 219--220
+    line-start
+    "    Verify return code: "
+    (one-or-more not-newline)
+    "\n"
+    ;; according to apps/s_client.c line 1515 this is always the last
+    ;; line that is printed by s_client before the real data
+    "---\n")
+
+   ;; `gnutls` regexp
+   (sequence
+    ;; see src/cli.c lines 721--
+    (sequence line-start "- Simple Client Mode:\n")
+    (zero-or-more
+     (or
+      "\n" ; ignore blank lines
+      ;; XXX: we have no way of knowing if the STARTTLS handshake
+      ;; sequence has completed successfully, because `gnutls` will
+      ;; only report failure.
+      (sequence line-start "\*\*\* Starting TLS handshake\n"))))))
+ "Regexp matching end of TLS client informational messages.
+Client data stream begins after the last character matched by this.
+
+The default matches `openssl s_client' (version 0.9.8c) and
+`gnutls-cli' (version 2.0.1) output."
+  :version "22.1"
+  :type 'regexp
+  :group 'tls)
+
 (defun tls-certificate-information (der)
   "Parse X.509 certificate in DER format into an assoc list."
   (let ((certificate (concat "-----BEGIN CERTIFICATE-----\n"
@@ -130,6 +167,8 @@
        process cmd done)
     (if use-temp-buffer
        (setq buffer (generate-new-buffer " TLS")))
+    (save-excursion
+      (set-buffer buffer)
     (message "Opening TLS connection to `%s'..." host)
     (while (and (not done) (setq cmd (pop cmds)))
       (message "Opening TLS connection with `%s'..." cmd)
@@ -146,19 +185,34 @@
                              port)))))
        (while (and process
                    (memq (process-status process) '(open run))
-                   (save-excursion
-                     (set-buffer buffer) ;; XXX "blue moon" nntp.el bug
+                    (progn
                      (goto-char (point-min))
                      (not (setq done (re-search-forward tls-success nil t)))))
          (unless (accept-process-output process 1)
             (sit-for 1)))
        (message "Opening TLS connection with `%s'...%s" cmd
                 (if done "done" "failed"))
-       (if done
-           (setq done process)
-         (delete-process process))))
+        (if (not done)
+            (delete-process process)
+          ;; advance point to after all informational messages that
+          ;; `openssl s_client' and `gnutls' print
+          (let ((start-of-data nil))
+            (while
+                (not (setq start-of-data
+                           ;; the string matching `tls-end-of-info'
+                           ;; might come in separate chunks from
+                           ;; `accept-process-output', so start the
+                           ;; search where `tls-success' ended
+                           (save-excursion
+                             (if (re-search-forward tls-end-of-info nil t)
+                                 (match-end 0)))))
+              (accept-process-output process 1))
+            (if start-of-data
+                ;; move point to start of client data
+                (goto-char start-of-data)))
+          (setq done process))))
     (message "Opening TLS connection to `%s'...%s"
-            host (if done "done" "failed"))
+             host (if done "done" "failed")))
     (when use-temp-buffer
       (if done (set-process-buffer process nil))
       (kill-buffer buffer))