gpg agent lockup fix: Interrupt main loop when active_connections_value==0

[gnupg2.git] / agent / gpg-agent.c

diff --git a/agent/gpg-agent.c b/agent/gpg-agent.c
index 1bfe0f3ae2a9e10001c93008ee1b7a43dd69436e..121bb0ed4f6a7e8b9d3486c4855e3811776db57e 100644 (file)
--- a/agent/gpg-agent.c
+++ b/agent/gpg-agent.c
@@ -316,10 +316,10 @@ static int startup_signal_mask_valid;
 #endif
 
 /* Flag to indicate that a shutdown was requested.  */
-static int shutdown_pending;
+static int shutdown_pending; /* xxx threaded accesses lack locking */
 
 /* Counter for the currently running own socket checks.  */
-static int check_own_socket_running;
+static int check_own_socket_running; /* xxx threaded accesses lack locking */
 
 /* Flags to indicate that check_own_socket shall not be called.  */
 static int disable_check_own_socket;
@@ -328,7 +328,7 @@ static int disable_check_own_socket;
 static int is_supervised;
 
 /* Flag to inhibit socket removal in cleanup.  */
-static int inhibit_socket_removal;
+static int inhibit_socket_removal; /* xxx threaded accesses lack locking */
 
 /* It is possible that we are currently running under setuid permissions */
 static int maybe_setuid = 1;
@@ -386,7 +386,8 @@ static pid_t parent_pid = (pid_t)(-1);
 static pid_t main_thread_pid = (pid_t)(-1);
 
 /* Number of active connections.  */
-static int active_connections;
+static int active_connections_value;
+static npth_mutex_t active_connections_lock;
 
 /* This object is used to dispatch progress messages from Libgcrypt to
  * the right thread.  Given that we will have at max only a few dozen
@@ -1988,11 +1989,49 @@ get_agent_ssh_socket_name (void)
 }
 
 
+static void
+lock_active_connections (void)
+{
+  int err;
+
+  err = npth_mutex_lock (&active_connections_lock);
+  if (err)
+    log_fatal ("failed to acquire active connection count mutex: %s\n",
+              strerror (err));
+}
+
+static void
+unlock_active_connections (void)
+{
+  int err;
+
+  err = npth_mutex_unlock (&active_connections_lock);
+  if (err)
+    log_fatal ("failed to release active connection count mutex: %s\n",
+              strerror (err));
+}
+
 /* Return the number of active connections. */
 int
 get_agent_active_connection_count (void)
 {
-  return active_connections;
+  int value;
+
+  lock_active_connections();
+  value = active_connections_value;
+  unlock_active_connections();
+  return value;
+}
+
+/* Increment/decrement the number of active connections. */
+static void
+adjust_agent_active_connections (int delta)
+{
+  lock_active_connections();
+  active_connections_value += delta;
+  if (active_connections_value == 0)
+    interrupt_main_thread_loop ();
+  unlock_active_connections();
 }
 
 
@@ -2378,7 +2417,7 @@ handle_signal (int signo)
         log_info ("SIGTERM received - shutting down ...\n");
       else
         log_info ("SIGTERM received - still %i open connections\n",
-                 active_connections);
+                 get_agent_active_connection_count());
       shutdown_pending++;
       if (shutdown_pending > 2)
         {
@@ -2613,7 +2652,7 @@ putty_message_thread (void *arg)
 static void *
 do_start_connection_thread (ctrl_t ctrl)
 {
-  active_connections++;
+  adjust_agent_active_connections(+1);
   agent_init_default_ctrl (ctrl);
   if (opt.verbose && !DBG_IPC)
     log_info (_("handler 0x%lx for fd %d started\n"),
@@ -2626,7 +2665,7 @@ do_start_connection_thread (ctrl_t ctrl)
 
   agent_deinit_default_ctrl (ctrl);
   xfree (ctrl);
-  active_connections--;
+  adjust_agent_active_connections(-1);
   return NULL;
 }
 
@@ -2693,7 +2732,7 @@ start_connection_thread_ssh (void *arg)
   if (check_nonce (ctrl, &socket_nonce_ssh))
     return NULL;
 
-  active_connections++;
+  adjust_agent_active_connections(+1);
   agent_init_default_ctrl (ctrl);
   if (opt.verbose)
     log_info (_("ssh handler 0x%lx for fd %d started\n"),
@@ -2706,7 +2745,7 @@ start_connection_thread_ssh (void *arg)
 
   agent_deinit_default_ctrl (ctrl);
   xfree (ctrl);
-  active_connections--;
+  adjust_agent_active_connections(-1);
   return NULL;
 }
 
@@ -2773,6 +2812,10 @@ handle_connections (gnupg_fd_t listen_fd,
     { { CHECK_OWN_SOCKET_INTERVAL, 0 }, check_own_socket }
   };
 
+  ret = npth_mutex_init (&active_connections_lock, NULL);
+  if (ret)
+    log_fatal ("error allocating active connections mutex: %s\n",
+              strerror (ret));
 
   ret = npth_attr_init(&tattr);
   if (ret)
@@ -2869,7 +2912,7 @@ handle_connections (gnupg_fd_t listen_fd,
       /* Shutdown test.  */
       if (shutdown_pending)
         {
-          if (active_connections == 0)
+          if (get_agent_active_connection_count() == 0)
             break; /* ready */
 
           /* Do not accept new connections but keep on running the
@@ -2894,6 +2937,8 @@ handle_connections (gnupg_fd_t listen_fd,
 
       /* avoid a fine-grained timer if we don't need one: */
       timertbl[0].interval.tv_sec = need_tick () ? TIMERTICK_INTERVAL : 0;
+      /* avoid waking up to check sockets if we can count on inotify */
+      timertbl[1].interval.tv_sec = (my_inotify_fd == -1) ? CHECK_OWN_SOCKET_INTERVAL : 0;
 
       /* loop through all timers, fire any registered functions, and
          plan next timer to trigger */