使用 yocto 启用 systemd 服务

Question

嗨，这是我的图层树

├── conf
│   └── layer.conf
├── COPYING.MIT
├── README
└── recipes-hello
    ├── helloworld
    │   ├── helloworld-0.1
    │   │   ├── helloworld.c
    │   │   ├── helloworld.patch
    │   │   └── newhelloworld.c
    │   └── helloworld_0.1.bb
    ├── message
    │   ├── message-0.1
    │   │   └── message.txt
    │   └── message_0.1.bb
    └── service
        ├── service-0.1
        │   ├── test_systemd.service
        │   └── test_systemd.sh
        └── service_0.1.bb

这里 test_systemd.service 是必须调用 test_systemd.sh 的服务文件，我正在尝试使用 service_0.1.bb

来实现

    # This recipe performs the following tasks
    # 1) Install .sh file in /home/root/ and .sh script creates a random text file
    # 2) Install the .service file in systemd directory
    # 3) Invoke the .sh script via .service file
    inherit systemd

SUMMARY = "Install and start a systemd service"
SECTION = "examples"
LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"

#here we specify the source we want to build
SRC_URI = "file://test_systemd.sh"
SRC_URI += "file://test_systemd.service"
#here we specify the source directory, where we can do all the building and expect sources to be placed
S = "${WORKDIR}"

SYSTEMD_SERVICE_${PN} = "test_systemd.service"


#bitbake task
#created a directory /home/root for target install the script
do_install() {
             install -d ${D}/home/root
             install -m 0755 ${WORKDIR}/test_systemd.sh ${D}/home/root

             install -d ${D}{systemd_system_unitdir}
             install -m 0644 ${WORKDIR}/test_systemd.service ${D}{systemd_system_unitdir}
}

#Pack the path
FILES_${PN} += "/home/root"
FILES_${PN} += "/lib/systemd/system"

REQUIRED_DISTRO_FEATURES= "systemd"

问题是当我尝试 bitbake 系统配方时，bitbake 抛出错误提示 test_systemd.service 未找到。我设法通过先前的尝试在 RFS 中安装了这两个文件，但是当我包含 systemd 概念时。我得到没有这样的文件错误。可能是什么原因？错误信息

 NOTE: Executing SetScene Tasks
NOTE: Executing RunQueue Tasks
ERROR: service-0.1-r0 do_package: SYSTEMD_SERVICE_service value test_systemd.service does not exist
ERROR: service-0.1-r0 do_package: Function failed: systemd_populate_packages
ERROR: Logfile of failure stored in: /home/guest/yocto_practice/poky/build-beaglebone/tmp/work/cortexa8hf-neon-poky-linux-gnueabi/service/0.1-r0/temp/log.do_package.2860
ERROR: Task (/home/guest/yocto_practice/meta-testlayer/recipes-hello/service/service_0.1.bb:do_package) failed with exit code '1'
NOTE: Tasks Summary: Attempted 514 tasks of which 506 didn't need to be rerun and 1 failed.

Summary: 1 task failed:
  /home/guest/yocto_practice/meta-testlayer/recipes-hello/service/service_0.1.bb:do_package
Summary: There were 2 ERROR messages shown, returning a non-zero exit code.

此外，这是为 systemd 编写 bb 配方的正确方法吗？编写这个的意义是什么

#Pack the path
    FILES_${PN} += "/home/root"
    FILES_${PN} += "/lib/systemd/system"

没有这个 bitbake 会抛出错误。

Answer 1

SYSTEMD_SERVICE_${PN} += "file://test_systemd.service"

这应该是：

SYSTEMD_SERVICE_${PN} = "test_systemd.service"

其他说明（与错误无关）：

将东西安装到 /home 中可能不是一个好主意（您可以将 ${libexecdir} 用于其他脚本需要的脚本。
没有理由在 bb 文件中包含 do_install_append()：您可以将所有内容放入 do_install()
如果您的 Yocto 是最新的，使用 ${systemd_system_unitdir} 而不是 /lib/systemd/system 是个好主意（在旧版本中 ${systemd_unitdir}/system/ 有效）

Answer 2

为了解决这个打包错误，我使用了以下安装步骤

do_install() {
   install -d ${D}${bindir}
   install -m 0755 ${WORKDIR}/test_systemd.sh ${D}${bindir}
   install -d ${D}${systemd_unitdir}/system
   install -m 0644 ${WORKDIR}/test_systemd.service ${D}${systemd_unitdir}/system
}

使用 yocto 启用 systemd 服务

Enable systemd services using yocto

bitbake

yocto