PX4-Firmware（master版本）源代码 在Ubuntu 18.04 LTS下编译及部分问题解决

1.引言

本文主要介绍的是Ubuntu 18.04 LTS环境下，编译PX4的Firmware源码的过程和发现的问题。正文中不会介绍Ubuntu 18.04环境的安装过程，有需要的同学我后续再出相关教程。
官方教程：https://dev.px4.io/ 跳转链接：link
英文版，中文版都行，哪个看的懂就可以参考哪个；

1.1 准备工作

必备内容：

1. Ubuntu 18.04 系统环境
2. 良好的网络环境（基础编译环境搭建必备）

PX4的源代码可以去github网站去自行下载，也可以在终端中用指令下载。个人建议：网络环境好的的话直接指令下。代码下载指令如下：

git clone https://github.com/PX4/Firmware.git --recursive

PS：这里先不要直接下，如果你是刚安装好的Ubuntu系统，里面可能没有git相关指令。直接用上面的指令会报错。

一切开始之间需要注意一下权限问题，目前权限问题是我在18.04环境遇见的最为头疼的问题。还没有完全研究明白权限的影响程度，后续博文可能会单独开一篇讨论。我参考了全面版本权限处理问题的方法：
利用用户组“dialout”具体操作如下图：在终端中输入指令后，登出在登入即可。

移除modemmanager，这个主要印象串口问题，将会影响后续固件上传。

1.2 源代码问题

PX4-Firmware源码的版本可以自行选择，国内好多教程、二次开发基线版本均为v1.8.2（stable）。代码版本不同可能在编译的过程中出现新的问题，问题不可控，请自行取舍利弊。

下载网站：https://github.com/PX4/Firmware 跳转链接： link

PS：一种下载方式，点击图片中

把压缩包解压，这里解压出来的是master的代码；

后续代码问题看下文代码讲解。

1.3 一键搭建编译环境

官方教程中提供了两个sh脚本文件，可以下载后直接运行：

1. ubuntu.sh 包含Gazebo 9和jMAVSim两个仿真软件，同时包含NuttX/Pixhawk编译环境必备的工具；注意：这个脚本中无法安装FastRTPS。
2. ubuntu_sim_ros_melodic.sh包含上述中的内容外还增加了ROS“Melodic”系统。PS：Ros系统安装与否跟本文主题无关，此文不做过多的说明。

sh文件下载好后直接执行sh文件即可：

bash ./对应文件夹/ubuntu.sh

sh文件的好处是只要网络畅通的情况下，可以一次性把需要的编译环境全部安装完毕。如果中间断网或者手动停止后，可再次运营sh脚本完成后续安装。

上述两个sh文件可在网站直接下载，点击ubuntu.sh 和ubuntu_sim_ros_melodic.sh即可出现预览界面。提示：因为某些众所周知的原因，文件ubuntu_sim_ros_melodic.sh可能打不开，请用梯子重新打开。

此处将两个文件内容全部全部贴出，这是目前开发者网站中给的两个内容，后续可能更改。
ubuntu.sh

#! /usr/bin/env bash

## Bash script to setup PX4 development environment on Ubuntu LTS (18.04, 16.04).
## Can also be used in docker.
##
## Installs:
## - Common dependencies and tools for nuttx, jMAVSim, Gazebo
## - NuttX toolchain (omit with arg: --no-nuttx)
## - jMAVSim and Gazebo9 simulator (omit with arg: --no-sim-tools)
##
## Not Installs:
## - FastRTPS and FastCDR

set -e

INSTALL_NUTTX="true"
INSTALL_SIM="true"

# Parse arguments
for arg in "$@"
do
	if [[ $arg == "--no-nuttx" ]]; then
		INSTALL_NUTTX="false"
	fi

	if [[ $arg == "--no-sim-tools" ]]; then
		INSTALL_SIM="false"
	fi

done

# detect if running in docker
if [ -f /.dockerenv ]; then
	echo "Running within docker, installing initial dependencies";
	apt-get --quiet -y update && DEBIAN_FRONTEND=noninteractive apt-get --quiet -y install \
		ca-certificates \
		gnupg \
		lsb-core \
		sudo \
		wget \
		;
fi

# script directory
DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )

# check requirements.txt exists (script not run in source tree)
REQUIREMENTS_FILE="requirements.txt"
if [[ ! -f "${DIR}/${REQUIREMENTS_FILE}" ]]; then
	echo "FAILED: ${REQUIREMENTS_FILE} needed in same directory as ubuntu.sh (${DIR})."
	return 1
fi


# check ubuntu version
# instructions for 16.04, 18.04, 20.04
# otherwise warn and point to docker?
UBUNTU_RELEASE="`lsb_release -rs`"

if [[ "${UBUNTU_RELEASE}" == "14.04" ]]; then
	echo "Ubuntu 14.04 unsupported, see docker px4io/px4-dev-base"
	exit 1
elif [[ "${UBUNTU_RELEASE}" == "16.04" ]]; then
	echo "Ubuntu 16.04"
elif [[ "${UBUNTU_RELEASE}" == "18.04" ]]; then
	echo "Ubuntu 18.04"
elif [[ "${UBUNTU_RELEASE}" == "20.04" ]]; then
	echo "Ubuntu 20.04"
fi


echo
echo "Installing PX4 general dependencies"

sudo apt-get update -y --quiet
sudo DEBIAN_FRONTEND=noninteractive apt-get -y --quiet --no-install-recommends install \
	astyle \
	build-essential \
	ccache \
	clang \
	clang-tidy \
	cmake \
	cppcheck \
	doxygen \
	file \
	g++ \
	gcc \
	gdb \
	git \
	lcov \
	make \
	ninja-build \
	python3 \
	python3-dev \
	python3-pip \
	python3-setuptools \
	python3-wheel \
	rsync \
	shellcheck \
	unzip \
	xsltproc \
	zip \
	;

if [[ "${UBUNTU_RELEASE}" == "16.04" ]]; then
	echo "Installing Ubuntu 16.04 PX4-compatible ccache version"
	wget -O /tmp/ccache_3.4.1-1_amd64.deb http://launchpadlibrarian.net/356662933/ccache_3.4.1-1_amd64.deb
	sudo dpkg -i /tmp/ccache_3.4.1-1_amd64.deb
fi

# Python3 dependencies
echo
echo "Installing PX4 Python3 dependencies"
pip3 install --user -r ${DIR}/requirements.txt

# NuttX toolchain (arm-none-eabi-gcc)
if [[ $INSTALL_NUTTX == "true" ]]; then

	echo
	echo "Installing NuttX dependencies"

	sudo DEBIAN_FRONTEND=noninteractive apt-get -y --quiet --no-install-recommends install \
		autoconf \
		automake \
		bison \
		bzip2 \
		flex \
		gdb-multiarch \
		gperf \
		libncurses-dev \
		libtool \
		pkg-config \
		vim-common \
		;

	if [ -n "$USER" ]; then
		# add user to dialout group (serial port access)
		sudo usermod -a -G dialout $USER
	fi

	# arm-none-eabi-gcc
	NUTTX_GCC_VERSION="7-2017-q4-major"

if [ $(which arm-none-eabi-gcc) ]; then
	GCC_VER_STR=$(arm-none-eabi-gcc --version)
	GCC_FOUND_VER=$(echo $GCC_VER_STR | grep -c "${NUTTX_GCC_VERSION}")
fi

	if [[ "$GCC_FOUND_VER" == "1" ]]; then
		echo "arm-none-eabi-gcc-${NUTTX_GCC_VERSION} found, skipping installation"

	else
		echo "Installing arm-none-eabi-gcc-${NUTTX_GCC_VERSION}";
		wget -O /tmp/gcc-arm-none-eabi-${NUTTX_GCC_VERSION}-linux.tar.bz2 https://armkeil.blob.core.windows.net/developer/Files/downloads/gnu-rm/7-2017q4/gcc-arm-none-eabi-${NUTTX_GCC_VERSION}-linux.tar.bz2 && \
			sudo tar -jxf /tmp/gcc-arm-none-eabi-${NUTTX_GCC_VERSION}-linux.tar.bz2 -C /opt/;

		# add arm-none-eabi-gcc to user's PATH
		exportline="export PATH=/opt/gcc-arm-none-eabi-${NUTTX_GCC_VERSION}/bin:\$PATH"

		if grep -Fxq "$exportline" $HOME/.profile;
		then
			echo "${NUTTX_GCC_VERSION} path already set.";
		else
			echo $exportline >> $HOME/.profile;
		fi
	fi

fi

# Simulation tools
if [[ $INSTALL_SIM == "true" ]]; then

	echo
	echo "Installing PX4 simulation dependencies"

	# General simulation dependencies
	sudo DEBIAN_FRONTEND=noninteractive apt-get -y --quiet --no-install-recommends install \
		bc \
		;

	# Java 8 (jmavsim or fastrtps)
	sudo DEBIAN_FRONTEND=noninteractive apt-get -y --quiet --no-install-recommends install \
		ant \
		openjdk-8-jre \
		openjdk-8-jdk \
		;

    # Set Java 8 as default
    sudo update-alternatives --set java $(update-alternatives --list java | grep "java-8")

	# Gazebo
	sudo sh -c 'echo "deb http://packages.osrfoundation.org/gazebo/ubuntu-stable `lsb_release -cs` main" > /etc/apt/sources.list.d/gazebo-stable.list'
	wget http://packages.osrfoundation.org/gazebo.key -O - | sudo apt-key add -
	sudo DEBIAN_FRONTEND=noninteractive apt-get -y --quiet --no-install-recommends install \
		gazebo9 \
		gstreamer1.0-plugins-bad \
		gstreamer1.0-plugins-base \
		gstreamer1.0-plugins-good \
		gstreamer1.0-plugins-ugly \
		gstreamer1.0-libav \
		libeigen3-dev \
		libgazebo9-dev \
		libgstreamer-plugins-base1.0-dev \
		libimage-exiftool-perl \
		libopencv-dev \
		libxml2-utils \
		pkg-config \
		protobuf-compiler \
		;

fi

if [[ $INSTALL_NUTTX == "true" ]]; then
	echo
	echo "Reboot or logout, login computer before attempting to build NuttX targets"
fi

ubuntu_sim_ros_melodic.sh

#!/bin/bash

## Bash script for setting up ROS Melodic (with Gazebo 9) development environment for PX4 on Ubuntu LTS (18.04). 
## It installs the common dependencies for all targets (including Qt Creator)
##
## Installs:
## - Common dependencies libraries and tools as defined in `ubuntu_sim_common_deps.sh`
## - ROS Melodic (including Gazebo9)
## - MAVROS

if [[ $(lsb_release -sc) == *"xenial"* ]]; then
  echo "OS version detected as $(lsb_release -sc) (16.04)."
  echo "ROS Melodic requires at least Ubuntu 18.04."
  echo "Exiting ...."
  return 1;
fi

echo "Downloading dependent script 'ubuntu_sim_common_deps.sh'"
# Source the ubuntu_sim_common_deps.sh script directly from github
common_deps=$(wget https://raw.githubusercontent.com/PX4/Devguide/master/build_scripts/ubuntu_sim_common_deps.sh -O -)
wget_return_code=$?
# If there was an error downloading the dependent script, we must warn the user and exit at this point.
if [[ $wget_return_code -ne 0 ]]; then echo "Error downloading 'ubuntu_sim_common_deps.sh'. Sorry but I cannot proceed further :("; exit 1; fi
# Otherwise source the downloaded script.
. <(echo "${common_deps}")

# ROS Melodic
## Gazebo simulator dependencies
sudo apt-get install protobuf-compiler libeigen3-dev libopencv-dev -y

## ROS Gazebo: http://wiki.ros.org/melodic/Installation/Ubuntu
## Setup keys
sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'
sudo apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654
## For keyserver connection problems substitute hkp://pgp.mit.edu:80 or hkp://keyserver.ubuntu.com:80 above.
sudo apt-get update
## Get ROS/Gazebo
sudo apt install ros-melodic-desktop-full -y
## Initialize rosdep
sudo rosdep init
rosdep update
## Setup environment variables
rossource="source /opt/ros/melodic/setup.bash"
if grep -Fxq "$rossource" ~/.bashrc; then echo ROS setup.bash already in .bashrc;
else echo "$rossource" >> ~/.bashrc; fi
eval $rossource

## Install rosinstall and other dependencies
sudo apt install python-rosinstall python-rosinstall-generator python-wstool build-essential -y



# MAVROS: https://dev.px4.io/en/ros/mavros_installation.html
## Install dependencies
sudo apt-get install python-catkin-tools python-rosinstall-generator -y

## Create catkin workspace
mkdir -p ~/catkin_ws/src
cd ~/catkin_ws
catkin init
wstool init src


## Install MAVLink
###we use the Kinetic reference for all ROS distros as it's not distro-specific and up to date
rosinstall_generator --rosdistro kinetic mavlink | tee /tmp/mavros.rosinstall

## Build MAVROS
### Get source (upstream - released)
rosinstall_generator --upstream mavros | tee -a /tmp/mavros.rosinstall

### Setup workspace & install deps
wstool merge -t src /tmp/mavros.rosinstall
wstool update -t src
if ! rosdep install --from-paths src --ignore-src -y; then
    # (Use echo to trim leading/trailing whitespaces from the unsupported OS name
    unsupported_os=$(echo $(rosdep db 2>&1| grep Unsupported | awk -F: '{print $2}'))
    rosdep install --from-paths src --ignore-src --rosdistro melodic -y --os ubuntu:bionic
fi

if [[ ! -z $unsupported_os ]]; then
    >&2 echo -e "\033[31mYour OS ($unsupported_os) is unsupported. Assumed an Ubuntu 18.04 installation,"
    >&2 echo -e "and continued with the installation, but if things are not working as"
    >&2 echo -e "expected you have been warned."
fi

#Install geographiclib
sudo apt install geographiclib-tools -y
echo "Downloading dependent script 'install_geographiclib_datasets.sh'"
# Source the install_geographiclib_datasets.sh script directly from github
install_geo=$(wget https://raw.githubusercontent.com/mavlink/mavros/master/mavros/scripts/install_geographiclib_datasets.sh -O -)
wget_return_code=$?
# If there was an error downloading the dependent script, we must warn the user and exit at this point.
if [[ $wget_return_code -ne 0 ]]; then echo "Error downloading 'install_geographiclib_datasets.sh'. Sorry but I cannot proceed further :("; exit 1; fi
# Otherwise source the downloaded script.
sudo bash -c "$install_geo"

## Build!
catkin build
## Re-source environment to reflect new packages/build environment
catkin_ws_source="source ~/catkin_ws/devel/setup.bash"
if grep -Fxq "$catkin_ws_source" ~/.bashrc; then echo ROS catkin_ws setup.bash already in .bashrc; 
else echo "$catkin_ws_source" >> ~/.bashrc; fi
eval $catkin_ws_source

2.代码下载&编译

前面基本环境搭建很重要，直接影响整个编译能否成功。下面开始进行代码编译。首先，打开终端Terminal。

2.1 代码下载

此步仅限于：没有执行1.2节中所提内容或者通过github单独下载代码的情况。如果已经通过git指令下载好了完整的代码，请跳过此节，直接进入2.2节。

1. github单独下载代码的情况
   如果Firmware 是在github上通过压缩包形式下载的，则需要执行recursive指令。指令如下：

cd Firmware
git submodule update --init --recursive

2. 利用git命令下载完成代码
   如果前面没有下载Firmware代码，可按照如下步骤进行源代码下载：
   

终端中输入：

mkdir PX4

就会在Home文件夹下生成一个PX4文件夹
然后执行：

cd PX4

再执行：

git clone https://github.com/PX4/Firmware.git --recursive

就会在PX4文件下自动下载对应的Firmware。

2.2 代码编译

首先进入Firmware文件夹：

cd Firmware

我这里是基于master版本代码进行编译。注：可以在master代码版本上先进行分支建立切换对应版本，在执行编译。

图片中执行的是：

make px4_fmu-v2_default

这里make指令的区别是对应生成Pixhawk版本不一样，执行指令与版本对应关系如下图所示：

执行完毕后应该显示如下：

至此编译完成。

3.问题

出现问题不要怕，宗旨是出现什么问题就google什么问题，为什么用google？理由是好多问题度娘不出来。
1.编译过程中的问题
比如出现下面这个问题：

解决方法很简单：
1）先确定你的python是不是安装了toml这库；
怎么检查？操作如下
在终端中输入：

>python3
>help()
>modules

检查是否有toml
没有就按问题图片中提示的指令安装toml
注意：因为python2已经终结了，Firmware的编译中涉及到的python库均为装入python3的函数库。另外，前面运行的脚本已经让系统安装了python3。如果你的系统没有python3 请确保前面环境搭建中的每一项都已经安装完毕了。

2）如果你发现已经安装了toml 但是仍然出现这个界面，证明你用户权限有问题。我是在make指令前加了sudo ，同样编译成功了。
如果出现下图问题：

说明环境变量中gcc的路径有问题
请检查gcc的环境变量是否添加争取，我个人在此处卡了很久，而且找不到准确的解决方案。
我个人的解决方法是参考v1.8.2版本中gcc环境变量的设置方式进行操作的。目前已解决。

2.后续可能出现的问题
接前面的问题，如果用了sudo指令编译成功，你会发现在对应编译好的bin文件出现一个锁头的标志。查看属性，所属权为root。目前还没进行后续上传板子操作，目测可能会出现权限问题。后续更新再讨论。

4.后续

1.研究权限的影响
2.更新出现问题清单
3.ubuntu系统搭建教程