Ensure TLS negotiation progress

* src/gnutls.h (GNUTLS_EMACS_HANDSHAKES_LIMIT): Increase the
number of retries so that we try for about a minute.

* src/process.c (wait_reading_process_output): Ensure progress
for DNS resolution and TLS negotiation.

1 files changed, 29 insertions, 5 deletions

diff --git a/src/process.c b/src/process.c
index 85a4885bbf4..4359f681b45 100644
--- a/src/process.c
+++ b/src/process.c
@@ -120,6 +120,11 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #endif
 #endif
 
+#if defined HAVE_GETADDRINFO_A || defined HAVE_GNUTLS
+/* This is 0.1s in nanoseconds. */
+#define ASYNC_RETRY_NSEC 100000000
+#endif
+
 #ifdef WINDOWSNT
 extern int sys_select (int, fd_set *, fd_set *, fd_set *,
                        struct timespec *, void *);
@@ -4870,6 +4875,9 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
   struct timespec got_output_end_time = invalid_timespec ();
   enum { MINIMUM = -1, TIMEOUT, INFINITY } wait;
   int got_some_output = -1;
+#if defined HAVE_GETADDRINFO_A || defined HAVE_GNUTLS
+  bool retry_for_async;
+#endif
   ptrdiff_t count = SPECPDL_INDEX ();
 
   /* Close to the current time if known, an invalid timespec otherwise.  */
@@ -4922,6 +4930,7 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
         Lisp_Object process_list_head, aproc;
         struct Lisp_Process *p;
 
+        retry_for_async = false;
         FOR_EACH_PROCESS(process_list_head, aproc)
           {
             p = XPROCESS (aproc);
@@ -4935,6 +4944,8 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
                     Lisp_Object ip_addresses = check_for_dns (aproc);
                     if (!NILP (ip_addresses) && !EQ (ip_addresses, Qt))
                       connect_network_socket (aproc, ip_addresses);
+                    else
+                      retry_for_async = true;
                   }
 #endif
 #ifdef HAVE_GNUTLS
@@ -4950,12 +4961,16 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
                         gnutls_verify_boot (aproc, Qnil);
                         finish_after_tls_connection (aproc);
                       }
-                    else if (p->gnutls_handshakes_tried
-                             > GNUTLS_EMACS_HANDSHAKES_LIMIT)
+                    else
                       {
-                        deactivate_process (aproc);
-                        pset_status (p, list2 (Qfailed,
-                                               build_string ("TLS negotiation failed")));
+                        retry_for_async = true;
+                        if (p->gnutls_handshakes_tried
+                            > GNUTLS_EMACS_HANDSHAKES_LIMIT)
+                          {
+                            deactivate_process (aproc);
+                            pset_status (p, list2 (Qfailed,
+                                                   build_string ("TLS negotiation failed")));
+                          }
                       }
                   }
 #endif
@@ -5222,6 +5237,15 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
           if (timeout.tv_sec > 0 || timeout.tv_nsec > 0)
             now = invalid_timespec ();
 
+#if defined HAVE_GETADDRINFO_A || defined HAVE_GNUTLS
+          if (retry_for_async
+              && (timeout.tv_sec > 0 || timeout.tv_nsec > ASYNC_RETRY_NSEC))
+            {
+              timeout.tv_sec = 0;
+              timeout.tv_nsec = ASYNC_RETRY_NSEC;
+            }
+#endif
+
 #if defined (HAVE_NS)
           nfds = ns_select
 #elif defined (HAVE_GLIB)