[3971] Better handling errors when thread is stopped/started.

Also, improved some LFC unit tests.

src/bin/dhcp4/ctrl_dhcp4_srv.cc

@@ -1,4 +1,4 @@
-// Copyright (C) 2014 Internet Systems Consortium, Inc. ("ISC")
+// Copyright (C) 2014-2015 Internet Systems Consortium, Inc. ("ISC")
 //
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
@@ -19,7 +19,6 @@
 #include <hooks/hooks_manager.h>
 #include <dhcp4/json_config_parser.h>
 #include <dhcpsrv/cfgmgr.h>
-#include <dhcpsrv/timer_mgr.h>
 #include <config/command_mgr.h>
 #include <stats/stats_mgr.h>
 
@@ -124,9 +123,31 @@ ControlledDhcpv4Srv::processConfig(isc::data::ConstElementPtr config) {
         return (isc::config::createAnswer(1, err.str()));
     }
 
-    TimerMgr::instance()->stopThread();
+    // We're going to modify the timers configuration. This is not allowed
+    // when the thread is running.
+    try {
+        TimerMgr::instance()->stopThread();
+    } catch (const std::exception& ex) {
+        err << "Unable to stop worker thread running timers: "
+            << ex.what() << ".";
+        return (isc::config::createAnswer(1, err.str()));
+    }
+
     ConstElementPtr answer = configureDhcp4Server(*srv, config);
-    TimerMgr::instance()->startThread();
+
+    // Start worker thread if there are any timers installed. Note that
+    // we also start worker thread when the reconfiguration failed, because
+    // in that case we continue using an old configuration and the server
+    // should still run installed timers.
+    if (TimerMgr::instance()->timersCount() > 0) {
+        try {
+            TimerMgr::instance()->startThread();
+        } catch (const std::exception& ex) {
+            err << "Unable to start worker thread running timers: "
+                << ex.what() << ".";
+            return (isc::config::createAnswer(1, err.str()));
+        }
+    }
 
     // Check that configuration was successful. If not, do not reopen sockets
     // and don't bother with DDNS stuff.
@@ -165,7 +186,7 @@ ControlledDhcpv4Srv::processConfig(isc::data::ConstElementPtr config) {
 }
 
 ControlledDhcpv4Srv::ControlledDhcpv4Srv(uint16_t port /*= DHCP4_SERVER_PORT*/)
-    :Dhcpv4Srv(port) {
+    : Dhcpv4Srv(port), io_service_(), timer_mgr_(TimerMgr::instance()) {
     if (getInstance()) {
         isc_throw(InvalidOperation,
                   "There is another Dhcpv4Srv instance already.");
@@ -207,6 +228,9 @@ void ControlledDhcpv4Srv::shutdown() {
 ControlledDhcpv4Srv::~ControlledDhcpv4Srv() {
     cleanup();
 
+    // Stop worker thread running timers, if it is running.
+    timer_mgr_->stopThread();
+
     // Close the command socket (if it exists).
     CommandMgr::instance().closeCommandSocket();
 

src/bin/dhcp4/ctrl_dhcp4_srv.h

@@ -18,6 +18,7 @@
 #include <asiolink/asiolink.h>
 #include <cc/data.h>
 #include <cc/command_interpreter.h>
+#include <dhcpsrv/timer_mgr.h>
 #include <dhcp4/dhcp4_srv.h>
 
 namespace isc {
@@ -102,13 +103,7 @@ public:
     }
 
 
-protected:
-    /// @brief Static pointer to the sole instance of the DHCP server.
-    ///
-    /// This is required for config and command handlers to gain access to
-    /// the server
-    static ControlledDhcpv4Srv* server_;
-
+private:
     /// @brief Callback that will be called from iface_mgr when data
     /// is received over control socket.
     ///
@@ -117,9 +112,6 @@ protected:
     /// (that was sent from some yet unspecified sender).
     static void sessionReader(void);
 
-    /// @brief IOService object, used for all ASIO operations.
-    isc::asiolink::IOService io_service_;
-
     /// @brief Handler for processing 'shutdown' command
     ///
     /// This handler processes shutdown command, which initializes shutdown
@@ -157,6 +149,21 @@ protected:
     isc::data::ConstElementPtr
     commandConfigReloadHandler(const std::string& command,
                                isc::data::ConstElementPtr args);
+
+    /// @brief Static pointer to the sole instance of the DHCP server.
+    ///
+    /// This is required for config and command handlers to gain access to
+    /// the server
+    static ControlledDhcpv4Srv* server_;
+
+    /// @brief IOService object, used for all ASIO operations.
+    isc::asiolink::IOService io_service_;
+
+    /// @brief Instance of the @c TimerMgr.
+    ///
+    /// Shared pointer to the instance of timer @c TimerMgr is held here to
+    /// make sure that the @c TimerMgr outlives instance of this class.
+    TimerMgrPtr timer_mgr_;
 };
 
 }; // namespace isc::dhcp

src/bin/dhcp4/json_config_parser.cc

@@ -27,6 +27,7 @@
 #include <dhcpsrv/parsers/host_reservation_parser.h>
 #include <dhcpsrv/parsers/host_reservations_list_parser.h>
 #include <dhcpsrv/parsers/ifaces_config_parser.h>
+#include <dhcpsrv/timer_mgr.h>
 #include <config/command_mgr.h>
 #include <util/encode/hex.h>
 #include <util/strutil.h>
@@ -461,6 +462,9 @@ configureDhcp4Server(Dhcpv4Srv&, isc::data::ConstElementPtr config_set) {
     // so newly recreated configuration starts with first subnet-id equal 1.
     Subnet::resetSubnetID();
 
+    // Remove any existing timers.
+    TimerMgr::instance()->unregisterTimers();
+
     // Some of the values specified in the configuration depend on
     // other values. Typically, the values in the subnet4 structure
     // depend on the global values. Also, option values configuration

src/bin/dhcp4/tests/dhcp4_process_tests.sh.in

@@ -282,17 +282,17 @@ shutdown_test() {
     test_finish 0
 }
 
-# This test verifies that DHCPv4 can be reconfigured with a SIGHUP signal.
+# This test verifies that DHCPv4 can be configured to run lease file cleanup
+# periodially.
 lfc_timer_test() {
     # Log the start of the test and print test name.
     test_start "dhcpv4_srv.lfc_timer_test"
     # Remove dangling Kea instances and remove log files.
     cleanup
     # Create a configuration with the LFC enabled, by replacing the section
-    # with the lfc-interval parameter.
+    # with the lfc-interval and persist parameters.
     LFC_CONFIG=$(printf "${CONFIG}" | sed -e 's/\"lfc-interval\": 0/\"lfc-interval\": 1/g' \
                         | sed -e 's/\"persist\": false/\"persist\": true/g')
-    echo ${LFC_CONFIG}
     # Create new configuration file.
     create_config "${LFC_CONFIG}"
     # Instruct Kea to log to the specific file.
@@ -315,13 +315,51 @@ lfc_timer_test() {
         clean_exit 1
     fi
 
+    # Check if Kea emits the log message indicating that LFC is started.
     wait_for_message 10 "DHCPSRV_MEMFILE_LFC_EXECUTE" 1
     if [ ${_WAIT_FOR_MESSAGE} -eq 0 ]; then
         printf "ERROR: Server did not execute LFC.\n"
         clean_exit 1
     fi
 
-    sleep 3
+    # Give it a short time to run.
+    sleep 1
+
+    # Modify the interval.
+    LFC_CONFIG=$(printf "${CONFIG}" | sed -e 's/\"lfc-interval\": 1/\"lfc-interval\": 2/g')
+    # Create new configuration file.
+    create_config "${LFC_CONFIG}"
+
+    # Reconfigure the server with SIGHUP.
+    send_signal 1 ${bin}
+
+    # There should be two occurrences of the DHCP4_CONFIG_COMPLETE messages.
+    # Wait for it up to 10s.
+    wait_for_message 10 "DHCP4_CONFIG_COMPLETE" 2
+
+    # After receiving SIGHUP the server should get reconfigured and the
+    # reconfiguration should be noted in the log file. We should now
+    # have two configurations logged in the log file.
+    if [ ${_WAIT_FOR_MESSAGE} -eq 0 ]; then
+        printf "ERROR: server hasn't been reconfigured.\n"
+        clean_exit 1
+    else
+        printf "Server successfully reconfigured.\n"
+    fi
+
+    # Make sure the server is still operational.
+    get_pids ${bin}
+    if [ ${_GET_PIDS_NUM} -ne 1 ]; then
+        printf "ERROR: Kea process was killed when attempting reconfiguration.\n"
+        clean_exit 1
+    fi
+
+    # Wait for the LFC to run the second time.
+    wait_for_message 10 "DHCPSRV_MEMFILE_LFC_EXECUTE" 2
+    if [ ${_WAIT_FOR_MESSAGE} -eq 0 ]; then
+        printf "ERROR: Server did not execute LFC.\n"
+        clean_exit 1
+    fi
 
     # Send signal to Kea SIGTERM
     send_signal 15 ${bin}