mavlink: implement COMPONENT_INFORMATION

- implement COMP_METADATA_TYPE_VERSION & add component_version.json.gz to
  ROMFS for all targets.
- implement COMP_METADATA_TYPE_PARAMETER (only enabled for SITL currently)

src/modules/mavlink/CMakeLists.txt

@@ -64,6 +64,7 @@ px4_add_module(
 		module.yaml
 	DEPENDS
 		airspeed
+		component_information_header
 		drivers_accelerometer
 		drivers_barometer
 		drivers_gyroscope

src/modules/mavlink/mavlink_messages.cpp

@@ -104,6 +104,7 @@ using matrix::wrap_2pi;
 #include "streams/ATTITUDE_TARGET.hpp"
 #include "streams/AUTOPILOT_VERSION.hpp"
 #include "streams/COLLISION.hpp"
+#include "streams/COMPONENT_INFORMATION.hpp"
 #include "streams/DISTANCE_SENSOR.hpp"
 #include "streams/ESC_INFO.hpp"
 #include "streams/ESC_STATUS.hpp"
@@ -3151,6 +3152,9 @@ static const StreamListItem streams_list[] = {
 #if defined(STORAGE_INFORMATION_HPP)
 	create_stream_list_item<MavlinkStreamStorageInformation>(),
 #endif // STORAGE_INFORMATION_HPP
+#if defined(COMPONENT_INFORMATION_HPP)
+	create_stream_list_item<MavlinkStreamComponentInformation>(),
+#endif // COMPONENT_INFORMATION_HPP
 #if defined(RAW_RPM_HPP)
 	create_stream_list_item<MavlinkStreamRawRpm>()
 #endif // RAW_RPM_HPP

src/modules/mavlink/streams/COMPONENT_INFORMATION.hpp

@@ -0,0 +1,129 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2020 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.
+ *
+ ****************************************************************************/
+
+#ifndef COMPONENT_INFORMATION_HPP
+#define COMPONENT_INFORMATION_HPP
+
+#include "../mavlink_stream.h"
+
+#include <component_information/hashes.h>
+
+#include <px4_platform_common/defines.h>
+
+#include <sys/stat.h>
+
+class MavlinkStreamComponentInformation : public MavlinkStream
+{
+public:
+	static MavlinkStream *new_instance(Mavlink *mavlink) { return new MavlinkStreamComponentInformation(mavlink); }
+
+	static constexpr const char *get_name_static() { return "COMPONENT_INFORMATION"; }
+	static constexpr uint16_t get_id_static() { return MAVLINK_MSG_ID_COMPONENT_INFORMATION; }
+
+	const char *get_name() const override { return get_name_static(); }
+	uint16_t get_id() override { return get_id_static(); }
+
+	unsigned get_size() override
+	{
+		return 0; // never streamed
+	}
+
+	bool request_message(float param2, float param3, float param4,
+			     float param5, float param6, float param7) override
+	{
+		int type = (int)roundf(param2);
+		mavlink_component_information_t component_info{};
+		bool handled = false;
+		PX4_DEBUG("COMPONENT_INFORMATION request type %i", type);
+
+		switch (type) {
+		case COMP_METADATA_TYPE_VERSION:
+			component_info.metadata_uid = component_information::component_version_hash;
+			handled = get_component_information("component_version.json.gz", component_info);
+			break;
+
+		case COMP_METADATA_TYPE_PARAMETER:
+			component_info.metadata_uid = component_information::params_hash;
+			handled = get_component_information("params.json.gz", component_info);
+			break;
+
+		case COMP_METADATA_TYPE_COMMANDS:
+			// TODO
+			break;
+		}
+
+		if (handled) {
+			component_info.metadata_type = type;
+			component_info.time_boot_ms = hrt_absolute_time() / 1000;
+			mavlink_msg_component_information_send_struct(_mavlink->get_channel(), &component_info);
+		}
+
+		return handled;
+	}
+private:
+	explicit MavlinkStreamComponentInformation(Mavlink *mavlink) : MavlinkStream(mavlink) {}
+
+	bool send() override
+	{
+		return false;
+	}
+
+	bool get_component_information(const char *file, mavlink_component_information_t &component_info)
+	{
+		char full_path[64];
+		snprintf(full_path, sizeof(full_path), "%s/etc/extras/%s", PX4_ROOTFSDIR, file);
+		full_path[sizeof(full_path) - 1] = '\0';
+
+		if (file_exist(full_path)) {
+			if (snprintf(component_info.metadata_uri, sizeof(component_info.metadata_uri), "mftp://etc/extras/%s", file)
+			    >= (int)sizeof(component_info.metadata_uri)) {
+				PX4_ERR("path too long (%s)", file);
+				return false;
+			}
+
+		} else {
+			// TODO: use server uri
+			return false;
+		}
+
+		return true;
+	}
+
+	bool file_exist(const char *filename)
+	{
+		struct stat buffer;
+		return stat(filename, &buffer) == 0;
+	}
+};
+
+#endif // COMPONENT_INFORMATION_HPP