OpenWrt的开机启动服务(init scripts)

SysV风格的init启动

参考 https://wiki.openwrt.org/doc/techref/initscripts

以一个简单的例子来说明

#!/bin/sh /etc/rc.common
# Example script
# Copyright (C) 2007 OpenWrt.org
 
START=10
STOP=15
 
start() {        
        echo start
        # commands to launch application
}                 
 
stop() {          
        echo stop
        # commands to kill application 
}

第一行shebang #! 使用 /bin/sh /etc/rc.common 作为脚本解释器并在执行脚本前调用 main 和检查脚本

公用的 init script 方法有

start   # 启动服务
stop    # 停止服务
restart # 重启服务
reload  # 重新载入配置文件, 如果失败则重启
enable  # 启用开机自启动, 实际上是在/etc/rc.d/下创建S??和K??开头的软链
disable  # 禁用开机自启动, 实际上是删除/etc/rc.d/下对应的软链

脚本中 start() 和 stop() 是必须的

启动顺序

START= 和 STOP= 决定脚本启动时的次序. 启动时init.d会根据文件名顺序, 自动执行在/etc/rc.d中找到的脚本. 初始化脚本可以作为/etc/init.d/下文件的软链放置在/etc/rc.d/.
enable 和 disable 可以自动帮你创建对应的带序号的软链.
这个例子中START=10 会被链接到 /etc/rc.d/S10example, 启动时执行在START=9之后, 在START=11之前. 而STOP=15会被链接到 /etc/rc.d/K15example, 执行在STOP=14之后, 在STOP=16之前. 同一个启动数字的, 按字母顺序启动.

脚本中的 boot()
当存在boot()方法时, 系统启动时会调用boot()而不是start()

boot() {
    echo boot
    # commands to run on boot
}

你可以使用EXTRA_COMMANDS和EXTRA_HELP设置自定义的服务方法

EXTRA_COMMANDS="custom"
EXTRA_HELP="        custom  Help for the custom command"

custom() {
    echo "custom command"
    # do your custom stuff
}

多个自定义方法的添加

EXTRA_COMMANDS="custom1 custom2 custom3"
EXTRA_HELP=<<EOF
    custom1 Help for the custom1 command
    custom2 Help for the custom2 command
    custom3 Help for the custom3 command
EOF

custom1 () {
    echo "custom1"
    # do the stuff for custom1
}
custom2 () {
    echo "custom2"
    # do the stuff for custom2
}
custom3 () {
    echo "custom3"
    # do the stuff for custom3
}

快速查询所有服务的自启动状态, 可以使用以下命令

root@OpenWrt:~# for F in /etc/init.d/* ; do $F enabled && echo $F on || echo $F **disabled**; done
/etc/init.d/boot on
/etc/init.d/bootcount on
/etc/init.d/cron on
/etc/init.d/dnsmasq on
/etc/init.d/done on
/etc/init.d/dropbear on
/etc/init.d/firewall on
/etc/init.d/fstab on
/etc/init.d/gpio_switch on
/etc/init.d/led on
/etc/init.d/log on
/etc/init.d/network on
/etc/init.d/odhcpd on
/etc/init.d/rpcd on
/etc/init.d/samba on
/etc/init.d/ss-libev on
/etc/init.d/sysctl on
/etc/init.d/sysfixtime on
/etc/init.d/sysntpd on
/etc/init.d/system on
/etc/init.d/transmission on
/etc/init.d/uhttpd on
/etc/init.d/umount **disabled**
/etc/init.d/wifidog **disabled**

procd风格的init启动

procd init脚本与sysv风格的启动脚本区别在于

  • procd方式下, 服务必须以前台方式运行
  • 不同的shebang line: #!/bin/sh /etc/rc.common
  • 指定procd方式的声明 USE_PROCD=1

例如

#!/bin/sh /etc/rc.common

USE_PROCD=1

脚本格式说明

#!/bin/sh /etc/rc.common
# Copyright (C) 2008 OpenWrt.org    

# 启动的顺序，越大越靠后
START=98
# 停止的顺序, 越小越靠前
STOP=15

# 声明使用procd
USE_PROCD=1

BINLOADER_BIN="/usr/bin/binloader"

# start_service 函数必须要定义
start_service() {
  # 创建一个实例， 在procd看来一个应用程序可以多个实例
  # ubus call service list 可以查看实例
  procd_open_instance
  # 告知procd当binloader程序退出后尝试进行重启
  procd_set_param respawn
  # binloader执行的命令是"/usr/bin/binloader"， 若后面有参数可以直接在后面加上
  procd_set_param command "$BINLOADER_BIN"
  # 关闭实例
  procd_close_instance
}

# 定义退出服务器后需要做的操作
stop_service() {
  rm -f /var/run/binloader.pid
}

reload_service() {
  procd_send_signal clash
}

restart() {
  stop
  start
}

常用的start_service()语句

start_service() {
  procd_open_instance [instance_name]
  procd_set_param command /sbin/your_service_daemon -b -a --foo # service executable that has to run in **foreground**.
  procd_append_param command -bar 42 # append command parameters

  # respawn automatically if something died, be careful if you have an alternative process supervisor
  # if process dies sooner than respawn_threshold, it is considered crashed and after 5 retries the service is stopped
  procd_set_param respawn ${respawn_threshold:-3600} ${respawn_timeout:-5} ${respawn_retry:-5}

  procd_set_param env SOME_VARIABLE=funtimes  # pass environment variables to your process
  procd_set_param limits core="unlimited"  # If you need to set ulimit for your process
  procd_set_param file /var/etc/your_service.conf # /etc/init.d/your_service reload will restart the daemon if these files have changed
  procd_set_param netdev dev # likewise, except if dev's ifindex changes.
  procd_set_param data name=value ... # likewise, except if this data changes.
  procd_set_param stdout 1 # forward stdout of the command to logd
  procd_set_param stderr 1 # same for stderr
  procd_set_param user nobody # run service as user nobody
  procd_set_param pidfile /var/run/somefile.pid # write a pid file on instance start and remove it on stop
  procd_close_instance
}

被procd执行的程序不能是daemon后台程序，因为后台程序的主进程退出后在procd看来就是程序退出了，然后会进入respawn流程，之后重复启动和退出, 最后失败:

procd: Instance binloader::instance1 s in a crash loop 6 crashes, 0 seconds since last crash

参考

https://oldwiki.archive.openwrt.org/inbox/procd-init-scripts

posted on 2017-01-24 01:15  Milton  阅读(25076)  评论(0)  编辑  收藏  举报

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