sysdbd: Reconfigure the daemon on SIGHUP.

The current approach shuts down the backend collector thread and the frontend.
Then, the config file is parsed again and libsysdb's reconfiguration mechanism
is used to reconfigure all plugins.

diff --git a/src/tools/sysdbd/main.c b/src/tools/sysdbd/main.c
index c3bd2b845abce37362a9003a5ee42a9fd344a80f..4a4d55ec0ec9eb6e57abb7dcd501be923c0f8c86 100644 (file)
--- a/src/tools/sysdbd/main.c
+++ b/src/tools/sysdbd/main.c
@@ -71,6 +71,9 @@
 static sdb_plugin_loop_t plugin_main_loop = SDB_PLUGIN_LOOP_INIT;
 static sdb_fe_loop_t frontend_main_loop = SDB_FE_LOOP_INIT;
 
+static char *config_filename = NULL;
+static int reconfigure = 0;
+
 static char *default_listen_addresses[] = {
        DEFAULT_SOCKET,
 };
@@ -81,6 +84,15 @@ sigintterm_handler(int __attribute__((unused)) signo)
        frontend_main_loop.do_loop = 0;
 } /* sigintterm_handler */
 
+static void
+sighup_handler(int __attribute__((unused)) signo)
+{
+       /* (temporarily) terminate the plugin loop ... */
+       frontend_main_loop.do_loop = 0;
+       /* ... and tell the main loop to reconfigure the daemon */
+       reconfigure = 1;
+} /* sighup_handler */
+
 static void
 exit_usage(char *name, int status)
 {
@@ -168,6 +180,47 @@ daemonize(void)
        return 0;
 } /* daemonize */
 
+static int
+configure(void)
+{
+       int status;
+
+       if ((status = daemon_parse_config(config_filename))) {
+               if (status > 0)
+                       sdb_log(SDB_LOG_ERR, "Failed to parse configuration file.");
+               else
+                       sdb_log(SDB_LOG_ERR, "Failed to load configuration file.\n"
+                                       "\tCheck other error messages for details.");
+               return 1;
+       }
+
+       if (! listen_addresses) {
+               listen_addresses = default_listen_addresses;
+               listen_addresses_num = SDB_STATIC_ARRAY_LEN(default_listen_addresses);
+       }
+       return 0;
+} /* configure */
+
+static int
+do_reconfigure(void)
+{
+       int status;
+
+       sdb_log(SDB_LOG_INFO, "Reconfiguring SysDB daemon");
+
+       if (listen_addresses != default_listen_addresses)
+               daemon_free_listen_addresses();
+       listen_addresses = NULL;
+
+       sdb_plugin_reconfigure_init();
+       if ((status = configure()))
+               return status;
+       sdb_plugin_init_all();
+       sdb_plugin_reconfigure_finish();
+       sdb_connection_enable_logging();
+       return 0;
+} /* do_reconfigure */
+
 static void *
 backend_handler(void __attribute__((unused)) *data)
 {
@@ -180,49 +233,60 @@ static int
 main_loop(void)
 {
        pthread_t backend_thread;
-       size_t i;
 
-       plugin_main_loop.do_loop = 1;
-       frontend_main_loop.do_loop = 1;
+       while (42) {
+               size_t i;
 
-       memset(&backend_thread, 0, sizeof(backend_thread));
-       if (pthread_create(&backend_thread, /* attr = */ NULL,
-                               backend_handler, /* arg = */ NULL)) {
-               char buf[1024];
-               sdb_log(SDB_LOG_ERR, "Failed to create backend handler thread: %s",
-                               sdb_strerror(errno, buf, sizeof(buf)));
+               plugin_main_loop.do_loop = 1;
+               frontend_main_loop.do_loop = 1;
 
-               plugin_main_loop.do_loop = 0;
-               return 1;
-       }
+               memset(&backend_thread, 0, sizeof(backend_thread));
+               if (pthread_create(&backend_thread, /* attr = */ NULL,
+                                       backend_handler, /* arg = */ NULL)) {
+                       char buf[1024];
+                       sdb_log(SDB_LOG_ERR, "Failed to create backend handler thread: %s",
+                                       sdb_strerror(errno, buf, sizeof(buf)));
 
-       sdb_fe_socket_t *sock = sdb_fe_sock_create();
-       for (i = 0; i < listen_addresses_num; ++i)
-               if (sdb_fe_sock_add_listener(sock, listen_addresses[i]))
+                       plugin_main_loop.do_loop = 0;
                        break;
+               }
 
-       /* break on error */
-       if (i >= listen_addresses_num)
-               sdb_fe_sock_listen_and_serve(sock, &frontend_main_loop);
+               sdb_fe_socket_t *sock = sdb_fe_sock_create();
+               for (i = 0; i < listen_addresses_num; ++i)
+                       if (sdb_fe_sock_add_listener(sock, listen_addresses[i]))
+                               break;
+
+               /* break on error */
+               if (i >= listen_addresses_num)
+                       sdb_fe_sock_listen_and_serve(sock, &frontend_main_loop);
 
-       sdb_log(SDB_LOG_INFO, "Waiting for backend thread to terminate");
-       plugin_main_loop.do_loop = 0;
-       /* send a signal to interrupt the sleep call
-        * and make the thread shut down faster */
-       pthread_kill(backend_thread, SIGINT);
-       pthread_join(backend_thread, NULL);
-       sdb_fe_sock_destroy(sock);
+               sdb_log(SDB_LOG_INFO, "Waiting for backend thread to terminate");
+               plugin_main_loop.do_loop = 0;
+               /* send a signal to interrupt the sleep call
+                * and make the thread shut down faster */
+               pthread_kill(backend_thread, SIGINT);
+               pthread_join(backend_thread, NULL);
+               sdb_fe_sock_destroy(sock);
 
+               if (! reconfigure)
+                       break;
+
+               reconfigure = 0;
+               if (do_reconfigure()) {
+                       sdb_log(SDB_LOG_ERR, "Reconfiguration failed");
+                       break;
+               }
+       }
        return 0;
 } /* main_loop */
 
 int
 main(int argc, char **argv)
 {
-       char *config_filename = NULL;
        _Bool do_daemonize = 1;
 
        struct sigaction sa_intterm;
+       struct sigaction sa_hup;
        int status;
 
        sdb_error_set_logger(sdb_plugin_log);
@@ -257,20 +321,8 @@ main(int argc, char **argv)
 
        if (! config_filename)
                config_filename = CONFIGFILE;
-
-       if ((status = daemon_parse_config(config_filename))) {
-               if (status > 0)
-                       sdb_log(SDB_LOG_ERR, "Failed to parse configuration file.");
-               else
-                       sdb_log(SDB_LOG_ERR, "Failed to load configuration file.\n"
-                                       "\tCheck other error messages for details.");
-               exit(1);
-       }
-
-       if (! listen_addresses) {
-               listen_addresses = default_listen_addresses;
-               listen_addresses_num = SDB_STATIC_ARRAY_LEN(default_listen_addresses);
-       }
+       if ((status = configure()))
+               exit(status);
 
        memset(&sa_intterm, 0, sizeof(sa_intterm));
        sa_intterm.sa_handler = sigintterm_handler;
@@ -300,6 +352,17 @@ main(int argc, char **argv)
        sdb_plugin_init_all();
        plugin_main_loop.default_interval = SECS_TO_SDB_TIME(60);
 
+       memset(&sa_hup, 0, sizeof(sa_hup));
+       sa_hup.sa_handler = sighup_handler;
+       sa_hup.sa_flags = 0;
+
+       if (sigaction(SIGHUP, &sa_hup, /* old action */ NULL)) {
+               char errbuf[1024];
+               sdb_log(SDB_LOG_ERR, "Failed to install signal handler for "
+                               "SIGHUP: %s", sdb_strerror(errno, errbuf, sizeof(errbuf)));
+               exit(1);
+       }
+
        /* ignore, we see this, for example, if a client disconnects without
         * closing the connection cleanly */
        signal(SIGPIPE, SIG_IGN);