Limit number of GnuTLS handshakes per connection.

* gnutls.c (gnutls_log_function2i): Convenience log function.
(emacs_gnutls_read): Use new log functions,
`gnutls_handshakes_tried' process member, and
`GNUTLS_EMACS_HANDSHAKES_LIMIT' to limit the number of handshake
attempts per process (connection).

* gnutls.h: Add `GNUTLS_EMACS_HANDSHAKES_LIMIT' upper limit.  Add
convenience `GNUTLS_LOG2i' macro.

* process.c (make_process):
* process.h: Add integer `gnutls_handshakes_tried' member to
process struct.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/gnutls.h b/src/gnutls.h
index 474da77aec5..37b9a2eb4df 100644
--- a/src/gnutls.h
+++ b/src/gnutls.h
@@ -23,6 +23,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <gnutls/gnutls.h>
 #include <gnutls/x509.h>
 
+/* This limits the attempts to handshake per process (connection).  */
+#define GNUTLS_EMACS_HANDSHAKES_LIMIT 100
+
 typedef enum
 {
   /* Initialization stages.  */
@@ -53,6 +56,8 @@ typedef enum
 
 #define GNUTLS_LOG2(level, max, string, extra) do { if (level <= max) { gnutls_log_function2 (level, "(Emacs) " string, extra); } } while (0)
 
+#define GNUTLS_LOG2i(level, max, string, extra) do { if (level <= max) { gnutls_log_function2i (level, "(Emacs) " string, extra); } } while (0)
+
 extern EMACS_INT
 emacs_gnutls_write (struct Lisp_Process *proc, const char *buf, EMACS_INT nbyte);
 extern EMACS_INT