text: /****************************************************************************
   *
   *   Copyright (c) 2014 PX4 Development Team. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name PX4 nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <cstdlib>
  #include <cstring>
  #include <fcntl.h>
  #include <dirent.h>
  #include <memory>
  #include <pthread.h>
  #include <systemlib/err.h>
  #include <systemlib/systemlib.h>
  #include <systemlib/param/param.h>
  #include <systemlib/mixer/mixer.h>
  #include <systemlib/board_serial.h>
  #include <systemlib/scheduling_priorities.h>
  #include <systemlib/git_version.h>
  #include <version/version.h>
  #include <arch/board/board.h>
  #include <arch/chip/chip.h>
  
  #include "uavcan_main.hpp"
  #include "uavcan_servers.hpp"
  #include "uavcan_virtual_can_driver.hpp"
  
  #include <uavcan_posix/dynamic_node_id_server/file_event_tracer.hpp>
  #include <uavcan_posix/dynamic_node_id_server/file_storage_backend.hpp>
  #include <uavcan_posix/firmware_version_checker.hpp>
  
  #include <uORB/topics/vehicle_command.h>
  #include <uORB/topics/uavcan_parameter_request.h>
  #include <uORB/topics/uavcan_parameter_value.h>
  
  #include <v1.0/common/mavlink.h>
  
  //todo:The Inclusion of file_server_backend is killing
  // #include <sys/types.h> and leaving OK undefined
  # define OK 0
  
  
  
  /**
   * @file uavcan_servers.cpp
   *
   * Implements basic functionality of UAVCAN node.
   *
   * @author Pavel Kirienko <pavel.kirienko@gmail.com>
   *         David Sidrane <david_s5@nscdg.com>
   */
  
  /*
   * UavcanNode
   */
  UavcanServers *UavcanServers::_instance;
  UavcanServers::UavcanServers(uavcan::INode &main_node) :
  	_subnode_thread(-1),
  	_vdriver(NumIfaces, uavcan_stm32::SystemClock::instance(), main_node.getAllocator(), VirtualIfaceBlockAllocationQuota),
  	_subnode(_vdriver, uavcan_stm32::SystemClock::instance(), main_node.getAllocator()),
  	_main_node(main_node),
  	_tracer(),
  	_storage_backend(),
  	_fw_version_checker(),
  	_server_instance(_subnode, _storage_backend, _tracer),
  	_fileserver_backend(_subnode),
  	_node_info_retriever(_subnode),
  	_fw_upgrade_trigger(_subnode, _fw_version_checker),
  	_fw_server(_subnode, _fileserver_backend),
  	_count_in_progress(false),
  	_count_index(0),
  	_param_in_progress(0),
  	_param_index(0),
  	_param_list_in_progress(false),
  	_param_list_all_nodes(false),
  	_param_list_node_id(1),
  	_param_dirty_bitmap{0, 0, 0, 0},
  	_param_save_opcode(0),
  	_cmd_in_progress(false),
  	_param_response_pub(nullptr),
  	_param_getset_client(_subnode),
  	_param_opcode_client(_subnode),
  	_param_restartnode_client(_subnode),
  	_mutex_inited(false),
  	_check_fw(false),
  	_esc_enumeration_active(false),
  	_esc_enumeration_index(0),
  	_beep_pub(_subnode),
  	_enumeration_indication_sub(_subnode),
  	_enumeration_client(_subnode),
  	_enumeration_getset_client(_subnode),
  	_enumeration_save_client(_subnode)
  
  {
  }
  
  UavcanServers::~UavcanServers()
  {
  	if (_mutex_inited) {
  		(void)Lock::deinit(_subnode_mutex);
  	}
  
  	_main_node.getDispatcher().removeRxFrameListener();
  }
  
  int UavcanServers::stop()
  {
  	UavcanServers *server = instance();
  
  	if (server == nullptr) {
  		warnx("Already stopped");
  		return -1;
  	}
  
  	if (server->_subnode_thread) {
  		warnx("stopping fw srv thread...");
  		server->_subnode_thread_should_exit = true;
  		(void)pthread_join(server->_subnode_thread, NULL);
  	}
  
  	_instance = nullptr;
  
  	server->_main_node.getDispatcher().removeRxFrameListener();
  
  	delete server;
  	return 0;
  }
  
  int UavcanServers::start(uavcan::INode &main_node)
  {
  	if (_instance != nullptr) {
  		warnx("Already started");
  		return -1;
  	}
  
  	/*
  	 * Node init
  	 */
  	_instance = new UavcanServers(main_node);
  
  	if (_instance == nullptr) {
  		warnx("Out of memory");
  		return -2;
  	}
  
  	int rv  = _instance->init();
  
  	if (rv < 0) {
  		warnx("Node init failed: %d", rv);
  		delete _instance;
  		_instance = nullptr;
  		return rv;
  	}
  
  	/*
  	 * Start the thread. Normally it should never exit.
  	 */
  	pthread_attr_t tattr;
  	struct sched_param param;
  
  	pthread_attr_init(&tattr);
  	tattr.stacksize = StackSize;
  	param.sched_priority = Priority;
  	pthread_attr_setschedparam(&tattr, &param);
  
  	static auto run_trampoline = [](void *) {return UavcanServers::_instance->run(_instance);};
  
  	rv = pthread_create(&_instance->_subnode_thread, &tattr, static_cast<pthread_startroutine_t>(run_trampoline), NULL);
  
  	if (rv != 0) {
  		rv = -rv;
  		warnx("pthread_create() failed: %d", rv);
  		delete _instance;
  		_instance = nullptr;
  	}
  
  	return rv;
  }
  
  int UavcanServers::init()
  {
  	errno = 0;
  
  	/*
  	 * Initialize the mutex.
  	 * giving it its path
  	 */
  
  	int ret = Lock::init(_subnode_mutex);
  
  	if (ret < 0) {
  		warnx("Lock init: %d", errno);
  		return ret;
  	}
  
  	_mutex_inited = true;
  
  	_subnode.setNodeID(_main_node.getNodeID());
  	_main_node.getDispatcher().installRxFrameListener(&_vdriver);
  
  
  	/*
  	 * Initialize the fw version checker.
  	 * giving it its path
  	 */
  	ret = _fw_version_checker.createFwPaths(UAVCAN_FIRMWARE_PATH);
  
  	if (ret < 0) {
  		warnx("FirmwareVersionChecker init: %d, errno: %d", ret, errno);
  		return ret;
  	}
  
  	/* Start fw file server back */
  
  	ret = _fw_server.start();
  
  	if (ret < 0) {
  		warnx("BasicFileServer init: %d, errno: %d", ret, errno);
  		return ret;
  	}
  
  	/* Initialize storage back end for the node allocator using UAVCAN_NODE_DB_PATH directory */
  
  	ret = _storage_backend.init(UAVCAN_NODE_DB_PATH);
  
  	if (ret < 0) {
  		warnx("FileStorageBackend init: %d, errno: %d", ret, errno);
  		return ret;
  	}
  
  	/* Initialize trace in the UAVCAN_NODE_DB_PATH directory */
  
  	ret = _tracer.init(UAVCAN_LOG_FILE);
  
  	if (ret < 0) {
  		warnx("FileEventTracer init: %d, errno: %d", ret, errno);
  		return ret;
  	}
  
  	/* hardware version */
  	uavcan::protocol::HardwareVersion hwver;
  	UavcanNode::getHardwareVersion(hwver);
  
  	/* Initialize the dynamic node id server  */
  	ret = _server_instance.init(hwver.unique_id);
  
  	if (ret < 0) {
  		warnx("CentralizedServer init: %d", ret);
  		return ret;
  	}
  
  	/* Start node info retriever to fetch node info from new nodes */
  
  	ret = _node_info_retriever.start();
  
  	if (ret < 0) {
  		warnx("NodeInfoRetriever init: %d", ret);
  		return ret;
  	}
  
  	/* Start the fw version checker   */
  
  	ret = _fw_upgrade_trigger.start(_node_info_retriever, _fw_version_checker.getFirmwarePath());
  
  	if (ret < 0) {
  		warnx("FirmwareUpdateTrigger init: %d", ret);
  		return ret;
  	}
  
  	/*  Start the Node   */
  
  	return OK;
  }
  
  pthread_addr_t UavcanServers::run(pthread_addr_t)
  {
  	prctl(PR_SET_NAME, "uavcan fw srv", 0);
  
  	Lock lock(_subnode_mutex);
  
  	/*
  	Copy any firmware bundled in the ROMFS to the appropriate location on the
  	SD card, unless the user has copied other firmware for that device.
  	*/
  	unpackFwFromROMFS(UAVCAN_FIRMWARE_PATH, UAVCAN_ROMFS_FW_PATH);
  
  	/* the subscribe call needs to happen in the same thread,
  	 * so not in the constructor */
  	int cmd_sub = orb_subscribe(ORB_ID(vehicle_command));
  	int param_request_sub = orb_subscribe(ORB_ID(uavcan_parameter_request));
  	int armed_sub = orb_subscribe(ORB_ID(actuator_armed));
  
  	/* Set up shared service clients */
  	_param_getset_client.setCallback(GetSetCallback(this, &UavcanServers::cb_getset));
  	_param_opcode_client.setCallback(ExecuteOpcodeCallback(this, &UavcanServers::cb_opcode));
  	_param_restartnode_client.setCallback(RestartNodeCallback(this, &UavcanServers::cb_restart));
  	_enumeration_client.setCallback(EnumerationBeginCallback(this, &UavcanServers::cb_enumeration_begin));
  	_enumeration_indication_sub.start(EnumerationIndicationCallback(this, &UavcanServers::cb_enumeration_indication));
  	_enumeration_getset_client.setCallback(GetSetCallback(this, &UavcanServers::cb_enumeration_getset));
  	_enumeration_save_client.setCallback(ExecuteOpcodeCallback(this, &UavcanServers::cb_enumeration_save));
  
  	_count_in_progress = _param_in_progress = _param_list_in_progress = _cmd_in_progress = _param_list_all_nodes = false;
  	memset(_param_counts, 0, sizeof(_param_counts));
  
  	_esc_enumeration_active = false;
  	memset(_esc_enumeration_ids, 0, sizeof(_esc_enumeration_ids));
  	_esc_enumeration_index = 0;
  
  	while (!_subnode_thread_should_exit) {
  
  		if (_check_fw == true) {
  			_check_fw = false;
  			_node_info_retriever.invalidateAll();
  		}
  
  		const int spin_res = _subnode.spin(uavcan::MonotonicDuration::fromMSec(10));
  		if (spin_res < 0) {
  			warnx("node spin error %i", spin_res);
  		}
  
  		// Check for parameter requests (get/set/list)
  		bool param_request_ready;
  		orb_check(param_request_sub, &param_request_ready);
  
  		if (param_request_ready && !_param_list_in_progress && !_param_in_progress && !_count_in_progress) {
  			struct uavcan_parameter_request_s request;
  			orb_copy(ORB_ID(uavcan_parameter_request), param_request_sub, &request);
  
  			if (_param_counts[request.node_id]) {
  				/*
  				 * We know how many parameters are exposed by this node, so
  				 * process the request.
  				 */
  				if (request.message_type == MAVLINK_MSG_ID_PARAM_REQUEST_READ) {
  					uavcan::protocol::param::GetSet::Request req;
  					if (request.param_index >= 0) {
  						req.index = request.param_index;
  					} else {
  						req.name = (char*)request.param_id;
  					}
  
  					int call_res = _param_getset_client.call(request.node_id, req);
  					if (call_res < 0) {
  						warnx("UAVCAN command bridge: couldn't send GetSet: %d", call_res);
  					} else {
  						_param_in_progress = true;
  						_param_index = request.param_index;
  					}
  				} else if (request.message_type == MAVLINK_MSG_ID_PARAM_SET) {
  					uavcan::protocol::param::GetSet::Request req;
  					if (request.param_index >= 0) {
  						req.index = request.param_index;
  					} else {
  						req.name = (char*)request.param_id;
  					}
  
  					if (request.param_type == MAV_PARAM_TYPE_REAL32) {
  						req.value.to<uavcan::protocol::param::Value::Tag::real_value>() = request.real_value;
  					} else if (request.param_type == MAV_PARAM_TYPE_UINT8) {
  						req.value.to<uavcan::protocol::param::Value::Tag::boolean_value>() = request.int_value;
  					} else {
  						req.value.to<uavcan::protocol::param::Value::Tag::integer_value>() = request.int_value;
  					}
  
  					// Set the dirty bit for this node
  					set_node_params_dirty(request.node_id);
  
  					int call_res = _param_getset_client.call(request.node_id, req);
  					if (call_res < 0) {
  						warnx("UAVCAN command bridge: couldn't send GetSet: %d", call_res);
  					} else {
  						_param_in_progress = true;
  						_param_index = request.param_index;
  					}
  				} else if (request.message_type == MAVLINK_MSG_ID_PARAM_REQUEST_LIST) {
  					// This triggers the _param_list_in_progress case below.
  					_param_index = 0;
  					_param_list_in_progress = true;
  					_param_list_node_id = request.node_id;
  					_param_list_all_nodes = false;
  
  					warnx("UAVCAN command bridge: starting component-specific param list");
  				}
  			} else if (request.node_id == MAV_COMP_ID_ALL) {
  				if (request.message_type == MAVLINK_MSG_ID_PARAM_REQUEST_LIST) {
  					/*
  					 * This triggers the _param_list_in_progress case below,
  					 * but additionally iterates over all active nodes.
  					 */
  					_param_index = 0;
  					_param_list_in_progress = true;
  					_param_list_node_id = get_next_active_node_id(1);
  					_param_list_all_nodes = true;
  
  					warnx("UAVCAN command bridge: starting global param list with node %hhu", _param_list_node_id);
  
  					if (_param_counts[_param_list_node_id] == 0) {
  						param_count(_param_list_node_id);
  					}
  				}
  			} else {
  				/*
  				 * Need to know how many parameters this node has before we can
  				 * continue; count them now and then process the request.
  				 */
  				param_count(request.node_id);
  			}
  		}
  
  		// Handle parameter listing index/node ID advancement
  		if (_param_list_in_progress && !_param_in_progress && !_count_in_progress) {
  			if (_param_index >= _param_counts[_param_list_node_id]) {
  				warnx("UAVCAN command bridge: completed param list for node %hhu", _param_list_node_id);
  				// Reached the end of the current node's parameter set.
  				_param_list_in_progress = false;
  
  				if (_param_list_all_nodes) {
  					// We're listing all parameters for all nodes -- get the next node ID
  					uint8_t next_id = get_next_active_node_id(_param_list_node_id);
  					if (next_id < 128) {
  						_param_list_node_id = next_id;
  						/*
  						 * If there is a next node ID, check if that node's parameters
  						 * have been counted before. If not, do it now.
  						 */
  						if (_param_counts[_param_list_node_id] == 0) {
  							param_count(_param_list_node_id);
  						}
  						// Keep on listing.
  						_param_index = 0;
  						_param_list_in_progress = true;
  						warnx("UAVCAN command bridge: started param list for node %hhu", _param_list_node_id);
  					}
  				}
  			}
  		}
  
  		// Check if we're still listing, and need to get the next parameter
  		if (_param_list_in_progress && !_param_in_progress && !_count_in_progress) {
  			// Ready to request the next value -- _param_index is incremented
  			// after each successful fetch by cb_getset
  			uavcan::protocol::param::GetSet::Request req;
  			req.index = _param_index;
  
  			int call_res = _param_getset_client.call(_param_list_node_id, req);
  			if (call_res < 0) {
  				_param_list_in_progress = false;
  				warnx("UAVCAN command bridge: couldn't send param list GetSet: %d", call_res);
  			} else {
  				_param_in_progress = true;
  			}
  		}
  
  		// Check for ESC enumeration commands
  		bool cmd_ready;
  		orb_check(cmd_sub, &cmd_ready);
  
  		if (cmd_ready && !_cmd_in_progress) {
  			struct vehicle_command_s cmd;
  			orb_copy(ORB_ID(vehicle_command), cmd_sub, &cmd);
  
  			if (cmd.command == vehicle_command_s::VEHICLE_CMD_PREFLIGHT_UAVCAN) {
  				int command_id = static_cast<int>(cmd.param1 + 0.5f);
  				int node_id = static_cast<int>(cmd.param2 + 0.5f);
  				int call_res;
  
  				warnx("UAVCAN command bridge: received UAVCAN command ID %d, node ID %d", command_id, node_id);
  
  				switch (command_id) {
  				case 0:
  				case 1: {
  						_esc_enumeration_active = command_id;
  						_esc_enumeration_index = 0;
  						_esc_count = 0;
  						uavcan::protocol::enumeration::Begin::Request req;
  						req.parameter_name = "esc_index";
  						req.timeout_sec = _esc_enumeration_active ? 65535 : 0;
  						call_res = _enumeration_client.call(get_next_active_node_id(1), req);
  						if (call_res < 0) {
  							warnx("UAVCAN ESC enumeration: couldn't send initial Begin request: %d", call_res);
  						}
  						break;
  					}
  				default: {
  						warnx("UAVCAN command bridge: unknown command ID %d", command_id);
  						break;
  					}
  				}
  			} else if (cmd.command == vehicle_command_s::VEHICLE_CMD_PREFLIGHT_STORAGE) {
  				int command_id = static_cast<int>(cmd.param1 + 0.5f);
  
  				warnx("UAVCAN command bridge: received storage command ID %d", command_id);
  
  				switch (command_id) {
  				case 1: {
  						// Param save request
  						int node_id;
  						node_id = get_next_dirty_node_id(1);
  						if (node_id < 128) {
  							_param_save_opcode = uavcan::protocol::param::ExecuteOpcode::Request::OPCODE_SAVE;
  							param_opcode(node_id);
  						}
  						break;
  					}
  				case 2: {
  						// Command is a param erase request -- apply it to all active nodes by setting the dirty bit
  						_param_save_opcode = uavcan::protocol::param::ExecuteOpcode::Request::OPCODE_ERASE;
  						for (int i = 1; i < 128; i = get_next_active_node_id(i)) {
  							set_node_params_dirty(i);
  						}
  						param_opcode(get_next_dirty_node_id(1));
  						break;
  					}
  				}
  			}
  		}
  
  		// Shut down once armed
  		// TODO (elsewhere): start up again once disarmed?
  		bool updated;
  		orb_check(armed_sub, &updated);
  		if (updated) {
  			struct actuator_armed_s armed;
  			orb_copy(ORB_ID(actuator_armed), armed_sub, &armed);
  
  			if (armed.armed && !armed.lockdown) {
  				warnx("UAVCAN command bridge: system armed, exiting now.");
  				break;
  			}
  		}
  	}
  
  	_subnode_thread_should_exit = false;
  
  	warnx("exiting");
  	return (pthread_addr_t) 0;
  }
  
  void UavcanServers::cb_getset(const uavcan::ServiceCallResult<uavcan::protocol::param::GetSet> &result)
  {
  	if (_count_in_progress) {
  		/*
  		 * Currently in parameter count mode:
  		 * Iterate over all parameters for the node to which the request was
  		 * originally sent, in order to find the maximum parameter ID. If a
  		 * request fails, set the node's parameter count to zero.
  		 */
  		uint8_t node_id = result.getCallID().server_node_id.get();
  
  		if (result.isSuccessful()) {
  			uavcan::protocol::param::GetSet::Response resp = result.getResponse();
  			if (resp.name.size()) {
  				_count_index++;
  				_param_counts[node_id] = _count_index;
  
  				uavcan::protocol::param::GetSet::Request req;
  				req.index = _count_index;
  
  				int call_res = _param_getset_client.call(result.getCallID().server_node_id, req);
  				if (call_res < 0) {
  					_count_in_progress = false;
  					_count_index = 0;
  					warnx("UAVCAN command bridge: couldn't send GetSet during param count: %d", call_res);
  				}
  			} else {
  				_count_in_progress = false;
  				_count_index = 0;
  				warnx("UAVCAN command bridge: completed param count for node %hhu: %hhu", node_id, _param_counts[node_id]);
  			}
  		} else {
  			_param_counts[node_id] = 0;
  			_count_in_progress = false;
  			_count_index = 0;
  			warnx("UAVCAN command bridge: GetSet error during param count");
  		}
  	} else {
  		/*
  		 * Currently in parameter get/set mode:
  		 * Publish a uORB uavcan_parameter_value message containing the current value
  		 * of the parameter.
  		 */
  		if (result.isSuccessful()) {
  			uavcan::protocol::param::GetSet::Response param = result.getResponse();
  
  			struct uavcan_parameter_value_s response;
  			response.node_id = result.getCallID().server_node_id.get();
  			strncpy(response.param_id, param.name.c_str(), sizeof(response.param_id) - 1);
  			response.param_id[16] = '\0';
  			response.param_index = _param_index;
  			response.param_count = _param_counts[response.node_id];
  
  			if (param.value.is(uavcan::protocol::param::Value::Tag::integer_value)) {
  				response.param_type = MAV_PARAM_TYPE_INT64;
  				response.int_value = param.value.to<uavcan::protocol::param::Value::Tag::integer_value>();
  			} else if (param.value.is(uavcan::protocol::param::Value::Tag::real_value)) {
  				response.param_type = MAV_PARAM_TYPE_REAL32;
  				response.real_value = param.value.to<uavcan::protocol::param::Value::Tag::real_value>();
  			} else if (param.value.is(uavcan::protocol::param::Value::Tag::boolean_value)) {
  				response.param_type = MAV_PARAM_TYPE_UINT8;
  				response.int_value = param.value.to<uavcan::protocol::param::Value::Tag::boolean_value>();
  			}
  
  			if (_param_response_pub == nullptr) {
  				_param_response_pub = orb_advertise(ORB_ID(uavcan_parameter_value), &response);
  			} else {
  				orb_publish(ORB_ID(uavcan_parameter_value), _param_response_pub, &response);
  			}
  		} else {
  			warnx("UAVCAN command bridge: GetSet error");
  		}
  
  		_param_in_progress = false;
  		_param_index++;
  	}
  }
  
  void UavcanServers::param_count(uavcan::NodeID node_id)
  {
  	uavcan::protocol::param::GetSet::Request req;
  	req.index = 0;
  	int call_res = _param_getset_client.call(node_id, req);
  	if (call_res < 0) {
  		warnx("UAVCAN command bridge: couldn't start parameter count: %d", call_res);
  	} else {
  		_count_in_progress = true;
  		_count_index = 0;
  		warnx("UAVCAN command bridge: starting param count");
  	}
  }
  
  void UavcanServers::param_opcode(uavcan::NodeID node_id)
  {
  	uavcan::protocol::param::ExecuteOpcode::Request opcode_req;
  	opcode_req.opcode = _param_save_opcode;
  	int call_res = _param_opcode_client.call(node_id, opcode_req);
  	if (call_res < 0) {
  		warnx("UAVCAN command bridge: couldn't send ExecuteOpcode: %d", call_res);
  	} else {
  		_cmd_in_progress = true;
  		warnx("UAVCAN command bridge: sent ExecuteOpcode");
  	}
  }
  
  void UavcanServers::cb_opcode(const uavcan::ServiceCallResult<uavcan::protocol::param::ExecuteOpcode> &result)
  {
  	bool success = result.isSuccessful();
  	uint8_t node_id = result.getCallID().server_node_id.get();
  	uavcan::protocol::param::ExecuteOpcode::Response resp = result.getResponse();
  	success &= resp.ok;
  	_cmd_in_progress = false;
  
  	if (!result.isSuccessful()) {
  		warnx("UAVCAN command bridge: save request for node %hhu timed out.", node_id);
  	} else if (!result.getResponse().ok) {
  		warnx("UAVCAN command bridge: save request for node %hhu rejected.", node_id);
  	} else {
  		warnx("UAVCAN command bridge: save request for node %hhu completed OK, restarting.", node_id);
  
  		uavcan::protocol::RestartNode::Request restart_req;
  		restart_req.magic_number = restart_req.MAGIC_NUMBER;
  		int call_res = _param_restartnode_client.call(node_id, restart_req);
  		if (call_res < 0) {
  			warnx("UAVCAN command bridge: couldn't send RestartNode: %d", call_res);
  		} else {
  			warnx("UAVCAN command bridge: sent RestartNode");
  			_cmd_in_progress = true;
  		}
  	}
  
  	if (!_cmd_in_progress) {
  		/*
  		 * Something went wrong, so cb_restart is never going to be called as a result of this request.
  		 * To ensure we try to execute the opcode on all nodes that permit it, get the next dirty node
  		 * ID and keep processing here. The dirty bit on the current node is still set, so the
  		 * save/erase attempt will occur when the next save/erase command is received over MAVLink.
  		 */
  		node_id = get_next_dirty_node_id(node_id);
  		if (node_id < 128) {
  			param_opcode(node_id);
  		}
  	}
  }
  
  void UavcanServers::cb_restart(const uavcan::ServiceCallResult<uavcan::protocol::RestartNode> &result)
  {
  	bool success = result.isSuccessful();
  	uint8_t node_id = result.getCallID().server_node_id.get();
  	uavcan::protocol::RestartNode::Response resp = result.getResponse();
  	success &= resp.ok;
  	_cmd_in_progress = false;
  
  	if (success) {
  		warnx("UAVCAN command bridge: restart request for node %hhu completed OK.", node_id);
  		// Clear the dirty flag
  		clear_node_params_dirty(node_id);
  	} else {
  		warnx("UAVCAN command bridge: restart request for node %hhu failed.", node_id);
  	}
  
  	// Get the next dirty node ID and send the same command to it
  	node_id = get_next_dirty_node_id(node_id);
  	if (node_id < 128) {
  		param_opcode(node_id);
  	}
  }
  
  uint8_t UavcanServers::get_next_active_node_id(uint8_t base)
  {
  	base++;
  	for (; base < 128 && (!_node_info_retriever.isNodeKnown(base) ||
  						   _subnode.getNodeID().get() == base); base++);
  	return base;
  }
  
  uint8_t UavcanServers::get_next_dirty_node_id(uint8_t base)
  {
  	base++;
  	for (; base < 128 && !are_node_params_dirty(base); base++);
  	return base;
  }
  
  void UavcanServers::cb_enumeration_begin(const uavcan::ServiceCallResult<uavcan::protocol::enumeration::Begin> &result)
  {
  	uint8_t next_id = get_next_active_node_id(result.getCallID().server_node_id.get());
  
  	if (!result.isSuccessful()) {
  		warnx("UAVCAN ESC enumeration: begin request for node %hhu timed out.", result.getCallID().server_node_id.get());
  	} else if (result.getResponse().error) {
  		warnx("UAVCAN ESC enumeration: begin request for node %hhu rejected: %hhu", result.getCallID().server_node_id.get(), result.getResponse().error);
  	} else {
  		_esc_count++;
  		warnx("UAVCAN ESC enumeration: begin request for node %hhu completed OK.", result.getCallID().server_node_id.get());
  	}
  
  	if (next_id < 128) {
  		// Still other active nodes to send the request to
  		uavcan::protocol::enumeration::Begin::Request req;
  		req.parameter_name = "esc_index";
  		req.timeout_sec = _esc_enumeration_active ? 65535 : 0;
  
  		int call_res = _enumeration_client.call(next_id, req);
  		if (call_res < 0) {
  			warnx("UAVCAN ESC enumeration: couldn't send Begin request: %d", call_res);
  		} else {
  			warnx("UAVCAN ESC enumeration: sent Begin request");
  		}
  	} else {
  		warnx("UAVCAN ESC enumeration: begun enumeration on all nodes.");
  	}
  }
  
  void UavcanServers::cb_enumeration_indication(const uavcan::ReceivedDataStructure<uavcan::protocol::enumeration::Indication> &msg)
  {
  	// Called whenever an ESC thinks it has received user input.
  	warnx("UAVCAN ESC enumeration: got indication");
  
  	if (!_esc_enumeration_active) {
  		// Ignore any messages received when we're not expecting them
  		return;
  	}
  
  	// First, check if we've already seen an indication from this ESC. If so,
  	// just re-issue the previous get/set request.
  	int i;
  	for (i = 0; i < _esc_enumeration_index; i++) {
  		if (_esc_enumeration_ids[i] == msg.getSrcNodeID().get()) {
  			warnx("UAVCAN ESC enumeration: already enumerated ESC ID %hhu as index %d", _esc_enumeration_ids[i], i);
  			break;
  		}
  	}
  
  	uavcan::protocol::param::GetSet::Request req;
  	req.name = "esc_index";
  	req.value.to<uavcan::protocol::param::Value::Tag::integer_value>() = i;
  
  	int call_res = _enumeration_getset_client.call(msg.getSrcNodeID(), req);
  	if (call_res < 0) {
  		warnx("UAVCAN ESC enumeration: couldn't send GetSet: %d", call_res);
  	} else {
  		warnx("UAVCAN ESC enumeration: sent GetSet to node %hhu (index %d)", _esc_enumeration_ids[i], i);
  	}
  }
  
  void UavcanServers::cb_enumeration_getset(const uavcan::ServiceCallResult<uavcan::protocol::param::GetSet> &result)
  {
  	if (!result.isSuccessful()) {
  		warnx("UAVCAN ESC enumeration: save request for node %hhu timed out.", result.getCallID().server_node_id.get());
  	} else {
  		warnx("UAVCAN ESC enumeration: save request for node %hhu completed OK.", result.getCallID().server_node_id.get());
  
  		uavcan::protocol::param::GetSet::Response resp = result.getResponse();
  		uint8_t esc_index = (uint8_t)resp.value.to<uavcan::protocol::param::Value::Tag::integer_value>();
  		esc_index = std::min((uint8_t)(uavcan::equipment::esc::RawCommand::FieldTypes::cmd::MaxSize - 1), esc_index);
  		_esc_enumeration_index = std::max(_esc_enumeration_index, (uint8_t)(esc_index + 1));
  
  		_esc_enumeration_ids[esc_index] = result.getCallID().server_node_id.get();
  
  		uavcan::protocol::param::ExecuteOpcode::Request opcode_req;
  		opcode_req.opcode = opcode_req.OPCODE_SAVE;
  		int call_res = _enumeration_save_client.call(result.getCallID().server_node_id, opcode_req);
  		if (call_res < 0) {
  			warnx("UAVCAN ESC enumeration: couldn't send ExecuteOpcode: %d", call_res);
  		} else {
  			warnx("UAVCAN ESC enumeration: sent ExecuteOpcode to node %hhu (index %hhu)", _esc_enumeration_ids[esc_index], esc_index);
  		}
  	}
  }
  
  void UavcanServers::cb_enumeration_save(const uavcan::ServiceCallResult<uavcan::protocol::param::ExecuteOpcode> &result)
  {
  	uavcan::equipment::indication::BeepCommand beep;
  
  	if (!result.isSuccessful()) {
  		warnx("UAVCAN ESC enumeration: save request for node %hhu timed out.", result.getCallID().server_node_id.get());
  		beep.frequency = 880.0f;
  		beep.duration = 1.0f;
  	} else if (!result.getResponse().ok) {
  		warnx("UAVCAN ESC enumeration: save request for node %hhu rejected", result.getCallID().server_node_id.get());
  		beep.frequency = 880.0f;
  		beep.duration = 1.0f;
  	} else {
  		warnx("UAVCAN ESC enumeration: save request for node %hhu completed OK.", result.getCallID().server_node_id.get());
  		beep.frequency = 440.0f;
  		beep.duration = 0.25f;
  	}
  
  	(void)_beep_pub.broadcast(beep);
  
  	warnx("UAVCAN ESC enumeration: completed %hhu of %hhu", _esc_enumeration_index, _esc_count);
  
  	if (_esc_enumeration_index == uavcan::equipment::esc::RawCommand::FieldTypes::cmd::MaxSize - 1 ||
  			_esc_enumeration_index == _esc_count) {
  		_esc_enumeration_active = false;
  
  		// Tell all ESCs to stop enumerating
  		uavcan::protocol::enumeration::Begin::Request req;
  		req.parameter_name = "esc_index";
  		req.timeout_sec = 0;
  		int call_res = _enumeration_client.call(get_next_active_node_id(1), req);
  		if (call_res < 0) {
  			warnx("UAVCAN ESC enumeration: couldn't send Begin request to stop enumeration: %d", call_res);
  		} else {
  			warnx("UAVCAN ESC enumeration: sent Begin request to stop enumeration");
  		}
  	}
  }
  
  void UavcanServers::unpackFwFromROMFS(const char* sd_path, const char* romfs_path) {
  	/*
  	Copy the ROMFS firmware directory to the appropriate location on SD, without
  	overriding any firmware the user has already loaded there.
  
  	The SD firmware directory structure is along the lines of:
  
  		/fs/microsd/fw
  		-	/c
  		-	-	/1a2b3c4d.bin			cache file (copy of /fs/microsd/fw/org.pixhawk.nodename-v1/1.1/1a2b3c4d.bin)
  		-	/org.pixhawk.nodename-v1	device directory for org.pixhawk.nodename-v1
  		-	-	/1.0					version directory for hardware 1.0
  		-	-	/1.1					version directory for hardware 1.1
  		-	-	-	/1a2b3c4d.bin		firmware file for org.pixhawk.nodename-v1 nodes, hardware version 1.1
  		-	/com.example.othernode-v3	device directory for com.example.othernode-v3
  		-	-	/1.0					version directory for hardawre 1.0
  		-	-	-	/deadbeef.bin		firmware file for com.example.othernode-v3, hardware version 1.0
  
  	The ROMFS directory structure is the same, but located at /etc/uavcan/fw
  
  	We iterate over all device directories in the ROMFS base directory, and create
  	corresponding device directories on the SD card if they don't already exist.
  
  	In each device directory, we iterate over each version directory and create a
  	corresponding version directory on the SD card if it doesn't already exist.
  
  	In each version directory, we remove any files with a name starting with "romfs_"
  	in the corresponding directory on the SD card that don't match the bundled firmware
  	filename; if the directory is empty after that process, we copy the bundled firmware.
  	*/
  	const size_t maxlen = UAVCAN_MAX_PATH_LENGTH;
  	const size_t sd_path_len = strlen(sd_path);
  	const size_t romfs_path_len = strlen(romfs_path);
  	struct stat sb;
  	int rv;
  	char dstpath[maxlen + 1];
  	char srcpath[maxlen + 1];
  
  	DIR* const romfs_dir = opendir(romfs_path);
  	if (!romfs_dir) {
  		warnx("base: couldn't open %s", romfs_path);
  		return;
  	}
  
  	memcpy(dstpath, sd_path, sd_path_len + 1);
  	memcpy(srcpath, romfs_path, romfs_path_len + 1);
  
  	// Iterate over all device directories in ROMFS
  	struct dirent* dev_dirent = NULL;
  	while ((dev_dirent = readdir(romfs_dir)) != NULL) {
  		// Skip if not a directory
  		if (!DIRENT_ISDIRECTORY(dev_dirent->d_type)) {
  			continue;
  		}
  
  		// Make sure the path fits
  		size_t dev_dirname_len = strlen(dev_dirent->d_name);
  		size_t srcpath_dev_len = romfs_path_len + 1 + dev_dirname_len;
  		if (srcpath_dev_len > maxlen) {
  			warnx("dev: srcpath '%s/%s' too long", romfs_path, dev_dirent->d_name);
  			continue;
  		}
  		size_t dstpath_dev_len = sd_path_len + 1 + dev_dirname_len;
  		if (dstpath_dev_len > maxlen) {
  			warnx("dev: dstpath '%s/%s' too long", sd_path, dev_dirent->d_name);
  			continue;
  		}
  
  		// Create the device name directory on the SD card if it doesn't already exist
  		dstpath[sd_path_len] = '/';
  		memcpy(&dstpath[sd_path_len + 1], dev_dirent->d_name, dev_dirname_len + 1);
  
  		if (stat(dstpath, &sb) != 0 || !S_ISDIR(sb.st_mode)) {
  			rv = mkdir(dstpath, S_IRWXU | S_IRWXG | S_IRWXO);
  			if (rv != 0) {
  				warnx("dev: couldn't create '%s'", dstpath);
  				continue;
  			}
  		}
  
  		// Set up the source path
  		srcpath[romfs_path_len] = '/';
  		memcpy(&srcpath[romfs_path_len + 1], dev_dirent->d_name, dev_dirname_len + 1);
  
  		DIR* const dev_dir = opendir(srcpath);
  		if (!dev_dir) {
  			warnx("dev: couldn't open '%s'", srcpath);
  			continue;
  		}
  
  		// Iterate over all version directories in the current ROMFS device directory
  		struct dirent* ver_dirent = NULL;
  		while ((ver_dirent = readdir(dev_dir)) != NULL) {
  			// Skip if not a directory
  			if (!DIRENT_ISDIRECTORY(ver_dirent->d_type)) {
  				continue;
  			}
  
  			// Make sure the path fits
  			size_t ver_dirname_len = strlen(ver_dirent->d_name);
  			size_t srcpath_ver_len = srcpath_dev_len + 1 + ver_dirname_len;
  			if (srcpath_ver_len > maxlen) {
  				warnx("ver: srcpath '%s/%s' too long", srcpath, ver_dirent->d_name);
  				continue;
  			}
  			size_t dstpath_ver_len = dstpath_dev_len + 1 + ver_dirname_len;
  			if (dstpath_ver_len > maxlen) {
  				warnx("ver: dstpath '%s/%s' too long", dstpath, ver_dirent->d_name);
  				continue;
  			}
  
  			// Create the device version directory on the SD card if it doesn't already exist
  			dstpath[dstpath_dev_len] = '/';
  			memcpy(&dstpath[dstpath_dev_len + 1], ver_dirent->d_name, ver_dirname_len + 1);
  
  			if (stat(dstpath, &sb) != 0 || !S_ISDIR(sb.st_mode)) {
  				rv = mkdir(dstpath, S_IRWXU | S_IRWXG | S_IRWXO);
  				if (rv != 0) {
  					warnx("ver: couldn't create '%s'", dstpath);
  					continue;
  				}
  			}
  
  			// Set up the source path
  			srcpath[srcpath_dev_len] = '/';
  			memcpy(&srcpath[srcpath_dev_len + 1], ver_dirent->d_name, ver_dirname_len + 1);
  
  			// Find the name of the bundled firmware file, or move on to the
  			// next directory if there's no file here.
  			DIR* const src_ver_dir = opendir(srcpath);
  			if (!src_ver_dir) {
  				warnx("ver: couldn't open '%s'", srcpath);
  				continue;
  			}
  
  			struct dirent* src_fw_dirent = NULL;
  			while ((src_fw_dirent = readdir(src_ver_dir)) != NULL &&
  					!DIRENT_ISFILE(src_fw_dirent->d_type));
  
  			if (!src_fw_dirent) {
  				(void)closedir(src_ver_dir);
  				continue;
  			}
  
  			size_t fw_len = strlen(src_fw_dirent->d_name);
  
  			bool copy_fw = true;
  
  			// Clear out any romfs_ files in the version directory on the SD card
  			DIR* const dst_ver_dir = opendir(dstpath);
  			if (!dst_ver_dir) {
  				warnx("unlink: couldn't open '%s'", dstpath);
  			} else {
  				struct dirent* fw_dirent = NULL;
  				while ((fw_dirent = readdir(dst_ver_dir)) != NULL) {
  					// Skip if not a file
  					if (!DIRENT_ISFILE(fw_dirent->d_type)) {
  						continue;
  					}
  
  					if (!memcmp(&fw_dirent->d_name[sizeof(UAVCAN_ROMFS_FW_PREFIX) - 1], src_fw_dirent->d_name, fw_len)) {
  						/*
  						 * Exact match between SD card filename and ROMFS filename; must be the same version
  						 * so don't bother deleting and rewriting it.
  						 */
  						copy_fw = false;
  					} else if (!memcmp(fw_dirent->d_name, UAVCAN_ROMFS_FW_PREFIX, sizeof(UAVCAN_ROMFS_FW_PREFIX) - 1)) {
  						size_t fw_len = strlen(fw_dirent->d_name);
  						size_t dstpath_fw_len = dstpath_ver_len + sizeof(UAVCAN_ROMFS_FW_PREFIX) + fw_len;
  						if (dstpath_fw_len > maxlen) {
  							// sizeof(prefix) includes trailing NUL, cancelling out the +1 for the path separator
  							warnx("unlink: path '%s/%s%s' too long", dstpath, UAVCAN_ROMFS_FW_PREFIX, fw_dirent->d_name);
  						} else {
  							// File name starts with "romfs_", delete it.
  							dstpath[dstpath_ver_len] = '/';
  							memcpy(&dstpath[dstpath_ver_len + 1], fw_dirent->d_name, fw_len + 1);
  							unlink(dstpath);
  
  							warnx("unlink: removed '%s/%s%s'", dstpath, UAVCAN_ROMFS_FW_PREFIX, fw_dirent->d_name);
  						}
  					} else {
  						// User file, don't copy firmware
  						copy_fw = false;
  					}
  				}
  				(void)closedir(dst_ver_dir);
  			}
  
  			// If we need to, copy the file from ROMFS to the SD card
  			if (copy_fw) {
  				size_t srcpath_fw_len = srcpath_ver_len + 1 + fw_len;
  				size_t dstpath_fw_len = dstpath_ver_len + sizeof(UAVCAN_ROMFS_FW_PREFIX) + fw_len;
  
  				if (srcpath_fw_len > maxlen) {
  					warnx("copy: srcpath '%s/%s' too long", srcpath, src_fw_dirent->d_name);
  				} else if (dstpath_fw_len > maxlen) {
  					warnx("copy: dstpath '%s/%s%s' too long", dstpath, UAVCAN_ROMFS_FW_PREFIX, src_fw_dirent->d_name);
  				} else {
  					// All OK, make the paths and copy the file
  					srcpath[srcpath_ver_len] = '/';
  					memcpy(&srcpath[srcpath_ver_len + 1], src_fw_dirent->d_name, fw_len + 1);
  
  					dstpath[dstpath_ver_len] = '/';
  					memcpy(&dstpath[dstpath_ver_len + 1], UAVCAN_ROMFS_FW_PREFIX, sizeof(UAVCAN_ROMFS_FW_PREFIX));
  					memcpy(&dstpath[dstpath_ver_len + sizeof(UAVCAN_ROMFS_FW_PREFIX)], src_fw_dirent->d_name, fw_len + 1);
  
  					rv = copyFw(dstpath, srcpath);
  					if (rv != 0) {
  						warnx("copy: '%s' -> '%s' failed: %d", srcpath, dstpath, rv);
  					} else {
  						warnx("copy: '%s' -> '%s' succeeded", srcpath, dstpath);
  					}
  				}
  			}
  
  			(void)closedir(src_ver_dir);
  		}
  
  		(void)closedir(dev_dir);
  	}
  
  	(void)closedir(romfs_dir);
  }
  
  int UavcanServers::copyFw(const char* dst, const char* src) {
  	int rv = 0;
  	int dfd, sfd;
  	uint8_t buffer[512];
  
  	dfd = open(dst, O_WRONLY | O_CREAT, 0666);
  	if (dfd < 0) {
  		warnx("copyFw: couldn't open dst");
  		return -errno;
  	}
  
  	sfd = open(src, O_RDONLY, 0);
  	if (sfd < 0) {
  		(void)close(dfd);
  		warnx("copyFw: couldn't open src");
  		return -errno;
  	}
  
  	ssize_t size = 0;
  	do {
  		size = read(sfd, buffer, sizeof(buffer));
  		if (size < 0) {
  			warnx("copyFw: couldn't read");
  			rv = -errno;
  		} else if (size > 0) {
  			rv = 0;
  			ssize_t remaining = size;
  			ssize_t total_written = 0;
  			ssize_t written = 0;
  			do {
  				written = write(dfd, &buffer[total_written], remaining);
  				if (written < 0) {
  					warnx("copyFw: couldn't write");
  					rv = -errno;
  				} else {
  					total_written += written;
  					remaining -=  written;
  				}
  			} while (written > 0 && remaining > 0);
  		}
  	} while (rv == 0 && size != 0);
  
  	(void)close(dfd);
  	(void)close(sfd);
  
  	return rv;
  }
  