XNU

• XUN
  • 名称
    • XNU= X is Not Unix
  • 概述
    • 英文
      • XNU kernel is part of the Darwin operating system for use in macOS and iOS operating systems.
    • 中文
      • XNU是：iOS（和tvOS、watchOS）的（操作系统）内核
      • XNU也是Darwin的一部分
        • Darwin是MacOS的操作系统内核
  • 特点
    • XNU is a hybrid kernel combining the Mach kernel developed at Carnegie Mellon University with components from FreeBSD and a C++ API for writing drivers called IOKit. XNU runs on x86_64 for both single processor and multi-processor configurations.
  • （开源代码）源码
    • opensource.apple.com
      • Source Browser (apple.com)
    • Github
      • https://github.com/apple/darwin-xnu
        • apple/darwin-xnu: The Darwin Kernel (mirror)
  • XNU组成
    • 2个主要部分
      • Mach：微内核=microkernel
        • 实现了操作系统的核心部分
      • BSD：内核=kernel
        • BSD在Mach的基础上，实现了更高层的各种功能
  • 代码组成=代码树
    • config - configurations for exported apis for supported architecture and platform
    • SETUP - Basic set of tools used for configuring the kernel, versioning and kextsymbol management.
    • EXTERNAL_HEADERS - Headers sourced from other projects to avoid dependency cycles when building. These headers should be regularly synced when source is updated.
    • libkern - C++ IOKit library code for handling of drivers and kexts.
    • libsa - kernel bootstrap code for startup
    • libsyscall - syscall library interface for userspace programs
    • libkdd - source for user library for parsing kernel data like kernel chunked data.
    • makedefs - top level rules and defines for kernel build.
    • osfmk - Mach kernel based subsystems
    • pexpert - Platform specific code like interrupt handling, atomics etc.
    • security - Mandatory Access Check policy interfaces and related implementation.
    • bsd - BSD subsystems code
    • tools - A set of utilities for testing, debugging and profiling kernel.

查看系统信息中会有XNU的版本等信息

• iOS 15.1，iPhone8的信息

  iPhone8-150:~ root# uname -a
  Darwin iPhone8-150 21.0.0 Darwin Kernel Version 21.0.0: Sun Aug 15 20:55:55 PDT 2021; root:xnu-8019.12.5~1/RELEASE_ARM64_T8015 iPhone10,1 arm Darwin
  

  • xnu-8019.12.5~1/RELEASE_ARM64_T8015
    • xnu是：iOS的内核
      • 版本是：8019.12.5