Introduction & Overview

1. 或許你會對MacOS啟動的哪些程序感到好奇
2. MacOS啟動的時間貌似變長了些許
3. 為什么有些來歷不明的程序總是在左右著你

Points

• OSX : Powered up > Firmware In Complete Control(Hardware) > BootX Loader(Kernel) > BSD Subsystem > Aqua User Interface

• BootX: Located in /System/Library/CoreServices > Loads Kernel Extensions (drivers, also known as kexts:/System/Library/Extensions)

• Initialization:Data Structures > I/O Kit > Mounts the root filesystem > loads mach_init > Launches the BSD init process >

• The init process launches:

  • shell scripts to start the system /etc/rc.boot and /etc/rc
  • sets the initial environment /etc/rc.common
  • load usefull functions/etc/hostconfig

• /etc/rc enables the swap file, sets the language for the system, and hands off control to /sbin/SystemStarter.

• SystemStarter:

  • examines /System/Library/StartupItems and /Library/StartupItems for applications that should be started at boot time.

• Returned to init, which launchesgetty, the console entry launches Login Window (/System/Library/CoreServices/loginwindow.app).

• Run Services in macOS

  • launchd is the cron in macOS
  • launchd distinguishes daemons and agents.

• Two main components in the launchd service

  • Job Definition : Define the service in special XML file.
  • Operations : Control the service using command line utility.

• Job Definition

  • The behavior of a daemons or agents are defined in a special XML file called a property list (*.plist) file.

• Type	Location	Run On Be Half Of
  User Agents	~/Library/LaunchAgents	Current Logined In User
  Global Agents	/Library/LaunchAgents	Current Logined In User
  Global Daemons	/Library/LaunchDaemons	Root Or the User Specify with Key Username
  System Agents	/System/Library/LaunchAgents	Current Logined In User
  System Daemons	/System/Library/LaunchDaemons	Root Or the User Specify with Key Username

  Operations.

  Getting information about available (loaded) jobs :

  $ launchctl list
  

  Getting information about a given job :

  $ launchctl list | grep <LABEL>
  

  Loading/Unloading a job (a global daemon) :

  $ launchctl load/unload /Library/LaunchDaemons/<LABEL>.plist
  

  Starting/Stop/Restart a job (a loaded job) :

  $ launchctl start/stop/restart <LABEL>
  

Simple Example

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN"
    "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>org.wso2.am</string>
    <key>ServiceDescription</key>
    <string>WSO2 API Manager Server</string>
    <key>ProgramArguments</key>
    <array>             
        <string>/bin/wso2server.sh</string>
    </array>
    <key>RunAtLoad</key>
    <false/>
</dict>
</plist>

Load & Run:

$ sudo launchctl load /Library/LaunchDaemons/org.wso2.am.plist
$ sudo launchctl start org.wso2.am

Test & Taste

$ sudo launchctl list | grep org.wso2.am

Bonus

#!/bin/bash

mkdir ~/.startup
# mac os startup item place , <sudo launchctl list> is ok also. 
ln -s /System/Library/StartupItems ~/.startup/sysStartupItems
ln -s /Library/StartupItems ~/.startup/libStartupItems
ln -s ~/Library/LaunchAgents ~/.startup/userAgents
ln -s /Library/LaunchAgents ~/.startup/libAgents
ln -s /Library/LaunchDaemons ~/.startup/libDaemons
ln -s /System/Library/LaunchDaemons ~/.startup/sysDaemons
ln -s /System/Library/LaunchAgents ~/.startup/sysAgents

function searchstartup(){
        grep -lrn $1 ~/.startup
}

Ref

• Booting Mac OS X
• Run Services In Mac OS X