modules/time_persistor: new time persistor module to save time to persistent storage (#23760)

src/modules/time_persistor/CMakeLists.txt

@@ -0,0 +1,43 @@
+############################################################################
+#
+#   Copyright (c) 2024 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.
+#
+############################################################################
+
+px4_add_module(
+	MODULE modules__time_persistor
+	MAIN time_persistor
+	COMPILE_FLAGS
+	SRCS
+		TimePersistor.cpp
+		TimePersistor.hpp
+	DEPENDS
+		px4_work_queue
+	)

src/modules/time_persistor/Kconfig

@@ -0,0 +1,5 @@
+menuconfig MODULES_TIME_PERSISTOR
+	bool "time_persistor"
+	default n
+	---help---
+		Enable support for time_persistor

src/modules/time_persistor/TimePersistor.cpp

@@ -0,0 +1,174 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2024 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 "TimePersistor.hpp"
+
+#include <errno.h>
+#include <px4_platform_common/log.h>
+
+TimePersistor::TimePersistor() :
+	ModuleParams(nullptr),
+	ScheduledWorkItem(MODULE_NAME, px4::wq_configurations::lp_default)
+{
+}
+
+TimePersistor::~TimePersistor()
+{
+	fclose(_file);
+}
+
+void TimePersistor::start()
+{
+	ScheduleOnInterval(1_s);
+}
+
+void TimePersistor::Run()
+{
+	if (should_exit()) {
+		ScheduleClear();
+		exit_and_cleanup();
+		return;
+	}
+
+	if (!_file) {
+		if (init() != PX4_OK) {
+			ScheduleClear();
+			exit_and_cleanup();
+			return;
+		}
+	}
+
+	struct timespec ts;
+
+	px4_clock_gettime(CLOCK_REALTIME, &ts);
+
+	if (write_time(ts.tv_sec) != PX4_OK) {
+		PX4_ERR("error writing RTC to time file");
+		exit_and_cleanup();
+		return;
+	}
+}
+
+int TimePersistor::task_spawn(int argc, char *argv[])
+{
+	TimePersistor *instance = new TimePersistor();
+
+	if (!instance) {
+		PX4_ERR("alloc failed");
+		return PX4_ERROR;
+	}
+
+	_object.store(instance);
+	_task_id = task_id_is_work_queue;
+
+	instance->start();
+	return PX4_OK;
+}
+
+int TimePersistor::custom_command(int argc, char *argv[])
+{
+	return print_usage("unknown command");
+}
+
+int TimePersistor::print_usage(const char *reason)
+{
+	if (reason) {
+		PX4_WARN("%s\n", reason);
+	}
+
+	PRINT_MODULE_DESCRIPTION(
+		R"DESCR_STR(
+### Description
+Writes the RTC time cyclically to a file and reloads this value on startup.
+This allows monotonic time on systems that only have a software RTC (that is not battery powered).
+Explicitly setting the time backwards (e.g. via system_time) is still possible.
+
+)DESCR_STR");
+
+	PRINT_MODULE_USAGE_NAME("time_persistor", "system");
+	PRINT_MODULE_USAGE_COMMAND("start");
+	PRINT_MODULE_USAGE_DEFAULT_COMMANDS();
+
+	return 0;
+}
+
+extern "C" __EXPORT int time_persistor_main(int argc, char *argv[])
+{
+	return TimePersistor::main(argc, argv);
+}
+
+int TimePersistor::init()
+{
+	if ((_file = fopen(TIME_FILE_PATH, "r+")) == nullptr) {
+		_file = fopen(TIME_FILE_PATH, "w+");
+	}
+
+	if (!_file) {
+		PX4_ERR("error opening the time file");
+		return PX4_ERROR;
+	}
+
+	time_t t;
+
+	if (read_time(&t) == PX4_OK) {
+		struct timespec ts;
+		ts.tv_sec = t;
+		ts.tv_nsec = 0;
+
+		px4_clock_settime(CLOCK_REALTIME, &ts);
+	}
+
+	return PX4_OK;
+}
+
+int TimePersistor::read_time(time_t *time)
+{
+	int status = PX4_OK;
+
+	status |= fseek(_file, 0, SEEK_SET);
+	status |= fread(time, sizeof(time_t), 1, _file) != 1;
+
+	return status;
+}
+
+int TimePersistor::write_time(const time_t time)
+{
+	int status = PX4_OK;
+
+	status |= fseek(_file, 0, SEEK_SET);
+	status |= fwrite(&time, sizeof(time_t), 1, _file) != 1;
+	status |= fflush(_file);
+	status |= fsync(fileno(_file));
+
+	return status;
+}

src/modules/time_persistor/TimePersistor.hpp

@@ -0,0 +1,71 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2024 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.
+ *
+ ****************************************************************************/
+
+#pragma once
+
+#include <px4_platform_common/module.h>
+#include <px4_platform_common/module_params.h>
+#include <px4_platform_common/px4_work_queue/ScheduledWorkItem.hpp>
+#include <px4_platform_common/time.h>
+
+static constexpr const auto TIME_FILE_PATH = PX4_STORAGEDIR "/time_save.bin";
+
+using namespace time_literals;
+
+class TimePersistor : public ModuleBase<TimePersistor>, public ModuleParams, public px4::ScheduledWorkItem
+{
+public:
+	TimePersistor();
+	~TimePersistor() override;
+
+	/** @see ModuleBase */
+	static int task_spawn(int argc, char *argv[]);
+
+	/** @see ModuleBase */
+	static int custom_command(int argc, char *argv[]);
+
+	/** @see ModuleBase */
+	static int print_usage(const char *reason = nullptr);
+
+	/** @see ModuleBase::run() */
+	void Run() override;
+
+	void start();
+
+private:
+	int init();
+	int read_time(time_t *time);
+	int write_time(const time_t time);
+
+	FILE *_file = 0;
+};