scd: Fix regression tracking the connection count.

* scd/scdaemon.c (get_active_connection_count): New.
(start_connection_thread): Bump ACTIVE_CONNECTIONS up and down.
* scd/command.c (cmd_getinfo): Add subcommand "connections".

--

Apply gpg-agent change to scdaemon.  See the commit in 2016-08-06:
    40d16029ed

Then, add kicking the loop, so that main loop can notice the change of
the connection.

Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>

scd/command.c

@@ -1372,30 +1372,26 @@ static const char hlp_getinfo[] =
   "Multi purpose command to return certain information.  \n"
   "Supported values of WHAT are:\n"
   "\n"
-  "version     - Return the version of the program.\n"
-  "pid         - Return the process id of the server.\n"
-  "\n"
-  "socket_name - Return the name of the socket.\n"
-  "\n"
-  "status - Return the status of the current reader (in the future, may\n"
-  "also return the status of all readers).  The status is a list of\n"
-  "one-character flags.  The following flags are currently defined:\n"
-  "  'u'  Usable card present.  This is the normal state during operation.\n"
-  "  'r'  Card removed.  A reset is necessary.\n"
-  "These flags are exclusive.\n"
-  "\n"
-  "reader_list - Return a list of detected card readers.  Does\n"
-  "              currently only work with the internal CCID driver.\n"
-  "\n"
-  "deny_admin  - Returns OK if admin commands are not allowed or\n"
-  "              GPG_ERR_GENERAL if admin commands are allowed.\n"
-  "\n"
-  "app_list    - Return a list of supported applications.  One\n"
-  "              application per line, fields delimited by colons,\n"
-  "              first field is the name.\n"
-  "\n"
-  "card_list   - Return a list of serial numbers of active cards,\n"
-  "              using a status response.";
+  "  version     - Return the version of the program.\n"
+  "  pid         - Return the process id of the server.\n"
+  "  socket_name - Return the name of the socket.\n"
+  "  connections - Return number of active connections.\n"
+  "  status      - Return the status of the current reader (in the future,\n"
+  "                may also return the status of all readers).  The status\n"
+  "                is a list of one-character flags.  The following flags\n"
+  "                are currently defined:\n"
+  "                  'u'  Usable card present.\n"
+  "                  'r'  Card removed.  A reset is necessary.\n"
+  "                These flags are exclusive.\n"
+  "  reader_list - Return a list of detected card readers.  Does\n"
+  "                currently only work with the internal CCID driver.\n"
+  "  deny_admin  - Returns OK if admin commands are not allowed or\n"
+  "                GPG_ERR_GENERAL if admin commands are allowed.\n"
+  "  app_list    - Return a list of supported applications.  One\n"
+  "                application per line, fields delimited by colons,\n"
+  "                first field is the name.\n"
+  "  card_list   - Return a list of serial numbers of active cards,\n"
+  "                using a status response.";
 static gpg_error_t
 cmd_getinfo (assuan_context_t ctx, char *line)
 {
@@ -1422,6 +1418,13 @@ cmd_getinfo (assuan_context_t ctx, char *line)
       else
         rc = gpg_error (GPG_ERR_NO_DATA);
     }
+  else if (!strcmp (line, "connections"))
+    {
+      char numbuf[20];
+
+      snprintf (numbuf, sizeof numbuf, "%d", get_active_connection_count ());
+      rc = assuan_send_data (ctx, numbuf, strlen (numbuf));
+    }
   else if (!strcmp (line, "status"))
     {
       ctrl_t ctrl = assuan_get_pointer (ctx);

scd/scdaemon.c

@@ -1150,6 +1150,8 @@ start_connection_thread (void *arg)
       return NULL;
     }
 
+  active_connections++;
+
   scd_init_default_ctrl (ctrl);
   if (opt.verbose)
     log_info (_("handler for fd %d started\n"),
@@ -1169,6 +1171,10 @@ start_connection_thread (void *arg)
 
   scd_deinit_default_ctrl (ctrl);
   xfree (ctrl);
+
+  if (--active_connections == 0)
+    scd_kick_the_loop ();
+
   return NULL;
 }
 
@@ -1349,3 +1355,10 @@ handle_connections (int listen_fd)
   log_info (_("%s %s stopped\n"), strusage(11), strusage(13));
   npth_attr_destroy (&tattr);
 }
+
+/* Return the number of active connections. */
+int
+get_active_connection_count (void)
+{
+  return active_connections;
+}

scd/scdaemon.h

@@ -125,6 +125,7 @@ void send_status_info (ctrl_t ctrl, const char *keyword, ...)
 void send_status_direct (ctrl_t ctrl, const char *keyword, const char *args);
 void send_client_notifications (app_t app, int removal);
 void scd_kick_the_loop (void);
+int get_active_connection_count (void);
 
 /*-- app.c --*/
 int scd_update_reader_status_file (void);