Implement asynch TLS negotiation

* src/gnutls.c (gnutls_try_handshake): Factor out into its own
function.
(emacs_gnutls_handshake): Use it.
(emacs_gnutls_read): Just return instead of retrying the handshake.

* src/process.c (finish_after_tls_connection): Factor out
into its own function.
(connect_network_socket): Use it.
(wait_reading_process_output): Retry TLS handshakes.
(wait_reading_process_output): Defer sentinel until TLS completes.

3 files changed, 119 insertions, 84 deletions

diff --git a/src/gnutls.c b/src/gnutls.c
index 948a0c56f14..6573c87cf78 100644
--- a/src/gnutls.c
+++ b/src/gnutls.c
@@ -397,11 +397,42 @@ gnutls_log_function2i (int level, const char *string, int extra)
   message ("gnutls.c: [%d] %s %d", level, string, extra);
 }
 
+int
+gnutls_try_handshake (struct Lisp_Process *proc)
+{
+  gnutls_session_t state = proc->gnutls_state;
+  int ret;
+
+  do
+    {
+      ret = gnutls_handshake (state);
+      emacs_gnutls_handle_error (state, ret);
+      QUIT;
+    }
+  while (ret < 0 && gnutls_error_is_fatal (ret) == 0 &&
+         ! proc->is_non_blocking_client);
+
+  proc->gnutls_initstage = GNUTLS_STAGE_HANDSHAKE_TRIED;
+
+  if (proc->is_non_blocking_client)
+    proc->gnutls_p = 1;
+
+  if (ret == GNUTLS_E_SUCCESS)
+    {
+      /* Here we're finally done.  */
+      proc->gnutls_initstage = GNUTLS_STAGE_READY;
+    }
+  else
+    {
+      //check_memory_full (gnutls_alert_send_appropriate (state, ret));
+    }
+  return ret;
+}
+
 static int
 emacs_gnutls_handshake (struct Lisp_Process *proc)
 {
   gnutls_session_t state = proc->gnutls_state;
-  int ret;
 
   if (proc->gnutls_initstage < GNUTLS_STAGE_HANDSHAKE_CANDO)
     return -1;
@@ -443,26 +474,7 @@ emacs_gnutls_handshake (struct Lisp_Process *proc)
       proc->gnutls_initstage = GNUTLS_STAGE_TRANSPORT_POINTERS_SET;
     }
 
-  do
-    {
-      ret = gnutls_handshake (state);
-      emacs_gnutls_handle_error (state, ret);
-      QUIT;
-    }
-  while (ret < 0 && gnutls_error_is_fatal (ret) == 0);
-
-  proc->gnutls_initstage = GNUTLS_STAGE_HANDSHAKE_TRIED;
-
-  if (ret == GNUTLS_E_SUCCESS)
-    {
-      /* Here we're finally done.  */
-      proc->gnutls_initstage = GNUTLS_STAGE_READY;
-    }
-  else
-    {
-      check_memory_full (gnutls_alert_send_appropriate (state, ret));
-    }
-  return ret;
+  return gnutls_try_handshake (proc);
 }
 
 ptrdiff_t
@@ -531,23 +543,8 @@ emacs_gnutls_read (struct Lisp_Process *proc, char *buf, ptrdiff_t nbyte)
   int log_level = proc->gnutls_log_level;
 
   if (proc->gnutls_initstage != GNUTLS_STAGE_READY)
-    {
-      /* If the handshake count is under the limit, try the handshake
-         again and increment the handshake count.  This count is kept
-         per process (connection), not globally.  */
-      if (proc->gnutls_handshakes_tried < GNUTLS_EMACS_HANDSHAKES_LIMIT)
-        {
-          proc->gnutls_handshakes_tried++;
-          emacs_gnutls_handshake (proc);
-          GNUTLS_LOG2i (5, log_level, "Retried handshake",
-                        proc->gnutls_handshakes_tried);
-          return -1;
-        }
+    return -1;
 
-      GNUTLS_LOG (2, log_level, "Giving up on handshake; resetting retries");
-      proc->gnutls_handshakes_tried = 0;
-      return 0;
-    }
   rtnval = gnutls_record_recv (state, buf, nbyte);
   if (rtnval >= 0)
     return rtnval;
diff --git a/src/gnutls.h b/src/gnutls.h
index 8e879c168bd..cb521350b9d 100644
--- a/src/gnutls.h
+++ b/src/gnutls.h
@@ -84,6 +84,7 @@ extern void emacs_gnutls_transport_set_errno (gnutls_session_t state, int err);
 #endif
 extern Lisp_Object emacs_gnutls_deinit (Lisp_Object);
 extern Lisp_Object emacs_gnutls_global_init (void);
+extern int gnutls_try_handshake (struct Lisp_Process *p);
 
 #endif
 
diff --git a/src/process.c b/src/process.c
index 9a3bcaed389..ec31ea87c7b 100644
--- a/src/process.c
+++ b/src/process.c
@@ -281,9 +281,7 @@ static int max_input_desc;
 
 /* Indexed by descriptor, gives the process (if any) for that descriptor.  */
 static Lisp_Object chan_process[FD_SETSIZE];
-#ifdef HAVE_GETADDRINFO_A
 static void wait_for_socket_fds (Lisp_Object process, char *name);
-#endif
 
 /* Alist of elements (NAME . PROCESS).  */
 static Lisp_Object Vprocess_alist;
@@ -3038,7 +3036,45 @@ void set_network_socket_coding_system (Lisp_Object proc)
     = !(!NILP (tem) || NILP (p->buffer) || !inherit_process_coding_system);
 }
 
-void connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses)
+#ifdef HAVE_GNUTLS
+void
+finish_after_tls_connection (Lisp_Object proc)
+{
+  struct Lisp_Process *p = XPROCESS (proc);
+  Lisp_Object contact = p->childp;
+  Lisp_Object result = Qt;
+
+  if (!NILP (Ffboundp (Qnsm_verify_connection)))
+    result = call3 (Qnsm_verify_connection,
+                    proc,
+                    Fplist_get (contact, QChost),
+                    Fplist_get (contact, QCservice));
+
+  if (NILP (result))
+    {
+      pset_status (p, list2 (Qfailed,
+                             build_string ("The Network Security Manager stopped the connections")));
+      deactivate_process (proc);
+    }
+  else
+    {
+      /* If we cleared the connection wait mask before we did
+         the TLS setup, then we have to say that the process
+         is finally "open" here. */
+      if (! FD_ISSET (p->outfd, &connect_wait_mask))
+        {
+          pset_status (p, Qrun);
+          /* Execute the sentinel here.  If we had relied on
+             status_notify to do it later, it will read input
+             from the process before calling the sentinel.  */
+          exec_sentinel (proc, build_string ("open\n"));
+        }
+    }
+}
+#endif
+
+void
+connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses)
 {
   ptrdiff_t count = SPECPDL_INDEX ();
   ptrdiff_t count1;
@@ -3359,8 +3395,10 @@ void connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses)
       boot = Fgnutls_boot (proc, XCAR (params), XCDR (params));
       p->gnutls_boot_parameters = Qnil;
 
-      if (NILP (boot) || STRINGP (boot) ||
-          p->gnutls_initstage != GNUTLS_STAGE_READY)
+      if (p->gnutls_initstage == GNUTLS_STAGE_READY)
+        /* Run sentinels, etc. */
+        finish_after_tls_connection (proc);
+      else if (p->gnutls_initstage != GNUTLS_STAGE_HANDSHAKE_TRIED)
         {
           deactivate_process (proc);
           if (NILP (boot))
@@ -3369,37 +3407,6 @@ void connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses)
           else
             pset_status (p, list2 (Qfailed, boot));
         }
-      else
-        {
-          Lisp_Object result = Qt;
-
-          if (!NILP (Ffboundp (Qnsm_verify_connection)))
-            result = call3 (Qnsm_verify_connection,
-                            proc,
-                            Fplist_get (contact, QChost),
-                            Fplist_get (contact, QCservice));
-
-          if (NILP (result))
-            {
-              pset_status (p, list2 (Qfailed,
-                                     build_string ("The Network Security Manager stopped the connections")));
-              deactivate_process (proc);
-            }
-          else
-            {
-              /* If we cleared the connection wait mask before we did
-                 the TLS setup, then we have to say that the process
-                 is finally "open" here. */
-              if (! FD_ISSET (p->outfd, &connect_wait_mask))
-                {
-                  pset_status (p, Qrun);
-                  /* Execute the sentinel here.  If we had relied on
-                     status_notify to do it later, it will read input
-                     from the process before calling the sentinel.  */
-                  exec_sentinel (proc, build_string ("open\n"));
-                }
-            }
-        }
     }
 #endif
 
@@ -4747,8 +4754,8 @@ static void
 wait_for_tls_negotiation (Lisp_Object process)
 {
 #ifdef HAVE_GNUTLS
-  while (EQ (XPROCESS (process)->status, Qconnect) &&
-         !NILP (XPROCESS (process)->gnutls_boot_parameters))
+  while (XPROCESS (process)->gnutls_p &&
+         XPROCESS (process)->gnutls_initstage != GNUTLS_STAGE_READY)
     {
       printf("Waiting for TLS...\n");
       wait_reading_process_output (0, 20 * 1000 * 1000, 0, 0, Qnil, NULL, 0);
@@ -4881,7 +4888,7 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
       if (! NILP (wait_for_cell) && ! NILP (XCAR (wait_for_cell)))
         break;
 
-#ifdef HAVE_GETADDRINFO_A
+#if defined (HAVE_GETADDRINFO_A) || defined (HAVE_GNUTLS)
       {
         Lisp_Object ip_addresses;
         Lisp_Object process_list_head, aproc;
@@ -4891,17 +4898,41 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
           {
             p = XPROCESS (aproc);
 
-            if (p->dns_requests &&
-                (! wait_proc || p == wait_proc))
+            if (! wait_proc || p == wait_proc)
               {
-                ip_addresses = check_for_dns (aproc);
-                if (!NILP (ip_addresses) &&
-                    !EQ (ip_addresses, Qt))
-                  connect_network_socket (aproc, ip_addresses);
+#ifdef HAVE_GETADDRINFO_A
+                /* Check for pending DNS requests. */
+                if (p->dns_requests)
+                  {
+                    ip_addresses = check_for_dns (aproc);
+                    if (!NILP (ip_addresses) &&
+                        !EQ (ip_addresses, Qt))
+                      connect_network_socket (aproc, ip_addresses);
+                  }
+#endif
+#ifdef HAVE_GNUTLS
+                /* Continue TLS negotiation. */
+                if (p->gnutls_initstage == GNUTLS_STAGE_HANDSHAKE_TRIED &&
+                    p->is_non_blocking_client)
+                  {
+                    gnutls_try_handshake (p);
+                    p->gnutls_handshakes_tried++;
+
+                    if (p->gnutls_initstage == GNUTLS_STAGE_READY)
+                      finish_after_tls_connection (aproc);
+                    else if (p->gnutls_handshakes_tried >
+                             GNUTLS_EMACS_HANDSHAKES_LIMIT)
+                      {
+                        deactivate_process (proc);
+                        pset_status (p, list2 (Qfailed,
+                                               build_string ("TLS negotiation failed")));
+                      }
+                  }
+#endif
               }
           }
       }
-#endif /* HAVE_GETADDRINFO_A */
+#endif /* GETADDRINFO_A or GNUTLS */
 
       /* Compute time from now till when time limit is up.  */
       /* Exit if already run out.  */
@@ -5522,7 +5553,13 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
                 }
               else
                 {
-                  if (NILP (p->gnutls_boot_parameters))
+#ifdef HAVE_GNUTLS
+                  /* If we have an incompletely set up TLS connection,
+                     then defer the sentinel signalling until
+                     later. */
+                  if (NILP (p->gnutls_boot_parameters) &&
+                      !p->gnutls_p)
+#endif
                     {
                       pset_status (p, Qrun);
                       /* Execute the sentinel here.  If we had relied on