[PATCH 2/4] agent: allow threads to interrupt main select loop with SIGCONT

[Daniel Kahn Gillmor]

* agent/gpg-agent.c (interrupt_main_thread_loop): new function on
  non-windows platforms, allows other threads to interrupt the main
  loop if there's something that the main loop might be interested in.

--

For example, the main loop might be interested in changes in program
state that affect the timers it expects to see.

I don't know how to do this on Windows platforms, but i welcome any
proposed improvements.

Signed-off-by: Daniel Kahn Gillmor <dkg at fifthhorseman.net>
---
 agent/agent.h     |  1 +
 agent/gpg-agent.c | 19 ++++++++++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/agent/agent.h b/agent/agent.h
index a3ec457..7bc061c 100644
--- a/agent/agent.h
+++ b/agent/agent.h
@@ -347,6 +347,7 @@ void *get_agent_scd_notify_event (void);
 #endif
 void agent_sighup_action (void);
 int map_pk_openpgp_to_gcry (int openpgp_algo);
+void interrupt_main_thread_loop (void);
 
 /*-- command.c --*/
 gpg_error_t agent_inq_pinentry_launched (ctrl_t ctrl, unsigned long pid);
diff --git a/agent/gpg-agent.c b/agent/gpg-agent.c
index f122e5b..c588e80 100644
--- a/agent/gpg-agent.c
+++ b/agent/gpg-agent.c
@@ -380,6 +380,9 @@ static char *current_logfile;
    watched. */
 static pid_t parent_pid = (pid_t)(-1);
 
+/* Record the pid of the main thread, for easier signalling */
+static pid_t main_thread_pid = (pid_t)(-1);
+
 /* Number of active connections.  */
 static int active_connections;
 
@@ -1994,7 +1997,7 @@ get_agent_scd_notify_event (void)
                                  GetCurrentProcess(), &h2,
                                  EVENT_MODIFY_STATE|SYNCHRONIZE, TRUE, 0))
         {
-          log_error ("setting syncronize for scd notify event failed: %s\n",
+          log_error ("setting synchronize for scd notify event failed: %s\n",
                      w32_strerror (-1) );
           CloseHandle (h);
         }
@@ -2320,6 +2323,10 @@ handle_signal (int signo)
       agent_sigusr2_action ();
       break;
 
+      /* nothing to do here, just take an extra cycle on the select loop */
+    case SIGCONT:
+      break;
+
     case SIGTERM:
       if (!shutdown_pending)
         log_info ("SIGTERM received - shutting down ...\n");
@@ -2658,6 +2665,13 @@ start_connection_thread_ssh (void *arg)
 }
 
 
+void interrupt_main_thread_loop (void)
+{
+#ifndef HAVE_W32_SYSTEM
+  kill (main_thread_pid, SIGCONT);
+#endif
+}
+
 /* helper function for readability: test whether a given struct
    timespec is set to all-zeros */
 static inline int
@@ -2726,8 +2740,10 @@ handle_connections (gnupg_fd_t listen_fd,
   npth_sigev_add (SIGUSR1);
   npth_sigev_add (SIGUSR2);
   npth_sigev_add (SIGINT);
+  npth_sigev_add (SIGCONT);
   npth_sigev_add (SIGTERM);
   npth_sigev_fini ();
+  main_thread_pid = getpid ();
 #else
 # ifdef HAVE_W32CE_SYSTEM
   /* Use a dummy event. */
@@ -2739,6 +2755,7 @@ handle_connections (gnupg_fd_t listen_fd,
 # endif
 #endif
 
+
   if (disable_check_own_socket)
     my_inotify_fd = -1;
   else if ((err = gnupg_inotify_watch_socket (&my_inotify_fd, socket_name)))
-- 
2.10.1