Android Binder IPC for Linux

binder-for-linux is an experimental project to evaluate the feasibility of porting Android Binder IPC subsystem to Ubuntu Linux.

GitHub: https://github.com/hungys/binder-for-linux

Transcript

1. Android Binder IPC for Linux 0456018 洪⾀昕
2. ANDROID BINDER IPC FOR LINUX Motivation ▸ Binder IPC subsystem is the core part of Android OS ▸ Activity, Service, BroadcastReceiver, ContentProvider ▸ ActivityManager, WindowManager, SurfaceFlinger ▸ Why Android propose another IPC mechanism? ▸ Feasibility of using Binder IPC on common Linux distros
3. In the Android platform, the binder is used for nearly everything that happens across processes in the core platform. Dianne Hackborn ANDROID BINDER IPC FOR LINUX
4. ANDROID BINDER IPC FOR LINUX Inter-Process Communication
5. ANDROID BINDER IPC FOR LINUX Unix IPC ▸ Pipe ▸ FIFO ▸ Socket ▸ SysV IPC ▸ Shared memory ▸ Message queue ▸ Semaphore
6. ANDROID BINDER IPC FOR LINUX Binder IPC ▸ Client/server architecture ▸ Remote procedure call ▸ Implemented as a Linux device driver ▸ Only one copy (from user to kernel) is needed
7. ANDROID BINDER IPC FOR LINUX Binder Architecture
8. ANDROID BINDER IPC FOR LINUX Binder Driver ▸ init() - Register a misc device (/dev/binder) ▸ open() - Open binder device ▸ mmap() - Allocate memory and map to kernel space ▸ ioctl() - Write/read IPC
9. ANDROID BINDER IPC FOR LINUX Binder Driver - initialization
10. ANDROID BINDER IPC FOR LINUX Binder Driver - device “file”
11. ANDROID BINDER IPC FOR LINUX Binder Driver - open device
12. ANDROID BINDER IPC FOR LINUX Binder Driver - memory map ▸ No more than 4MB
13. ANDROID BINDER IPC FOR LINUX Binder Driver - memory map
14. ANDROID BINDER IPC FOR LINUX Binder Driver - ioctl ▸ No read() & write() ▸ Commands ▸ BINDER_WRITE_READ ▸ BINDER_SET_MAX_THREADS ▸ BINDER_SET_CONTEXT_MGR ▸ BINDER_THREAD_EXIT
15. ANDROID BINDER IPC FOR LINUX Binder Driver - protocol ▸ BC_TRANSACTION <-> BR_TRANSACTION ▸ BC_REPLY <-> BR_REPLY ▸ ……
16. ANDROID BINDER IPC FOR LINUX Binder Driver - communication model
17. ANDROID BINDER IPC FOR LINUX Binder Driver - write
18. ANDROID BINDER IPC FOR LINUX Binder Driver - read
19. ANDROID BINDER IPC FOR LINUX Binder Driver - read
20. ANDROID BINDER IPC FOR LINUX Binder IPC subsystem
21. ANDROID BINDER IPC FOR LINUX Binder IPC subsystem - more! ▸ ProcessState, IPCThreadState ▸ Parcel ▸ AIDL
22. ANDROID BINDER IPC FOR LINUX Implementation ▸ Environment & code base ▸ Ubuntu 14.04.4 (Linux Kernel 4.2.0-27) ▸ Android 6.0.1_r46 ▸ Components to port ▸ binder & ashmem driver ▸ binder library ▸ Service Manager
23. ANDROID BINDER IPC FOR LINUX Issues & Challenges ▸ Not dynamic loadable ▸ Bionic C library ▸ Atomic library ▸ Dependencies to Android log daemon & SELinux
24. ANDROID BINDER IPC FOR LINUX Not dynamic loadable ▸ 10+ symbols are not exported by kernel ▸ Naive way: build kernel along with Binder driver statically ▸ Tricky way: kallsyms + function pointer redirection ▸ Run a shell script in Makefile ▸ Generate additional C source and header files ▸ Compile with Binder driver
25. ANDROID BINDER IPC FOR LINUX Not dynamic loadable
26. ANDROID BINDER IPC FOR LINUX Atomic library ▸ Have tried C++11 <atomic> -> no luck :( ▸ x86 supports atomic fetch and add!
27. ANDROID BINDER IPC FOR LINUX Evaluation - correctness ▸ Integer Adder Service ▸ Client: a = iter, b = iter+3 -> Server: calculate a+b
28. ANDROID BINDER IPC FOR LINUX Evaluation - latency
29. ANDROID BINDER IPC FOR LINUX Evaluation - analysis ▸ Not suitable for large payload ▸ mmap allows only 4MB ▸ deferred work (e.g. release buffer) in workqueue ▸ global lock everywhere :(
30. ANDROID BINDER IPC FOR LINUX Reference ▸ Linux Kernel & Android Framework source code ▸ ̽窼獈ቘ薹 Android ໐ஞ戔懯௏మ - ໐ஞ薹䯤缰̾ ▸ Binder羬ڜ - Gityuan玡ਮ ▸ Android IPC Mechanism by jserv ▸ Deep Dive into Android IPC/Binder Framework