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, 3 insertions, 0 deletions

diff --git a/src/process.c b/src/process.c
index f2f33a9eafc..dc43191ebef 100644
--- a/src/process.c
+++ b/src/process.c
@@ -640,7 +640,10 @@ make_process (Lisp_Object name)
 
 #ifdef HAVE_GNUTLS
   p->gnutls_initstage = GNUTLS_STAGE_EMPTY;
+  /* Default log level.  */
   p->gnutls_log_level = 0;
+  /* GnuTLS handshakes attempted for this connection.  */
+  p->gnutls_handshakes_tried = 0;
   p->gnutls_p = 0;
   p->gnutls_state = NULL;
   p->gnutls_x509_cred = NULL;