Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
System.loadLibrary("Unix, Native Code and why b...
Search
Júlio Zynger
March 16, 2018
Programming
0
810
System.loadLibrary("Unix, Native Code and why bother")
Presented at AppDevCon (Amsterdam) 2018
Júlio Zynger
March 16, 2018
Tweet
Share
More Decks by Júlio Zynger
See All by Júlio Zynger
Improving developer productivity with Gradle Enterprise in 2023
julioz
1
420
FloorPlan: Visualize databases' evolution
julioz
0
690
Publishing API & Continuous Deployment on Android
julioz
1
690
Continuous Deploy no Android
julioz
0
3.7k
Other Decks in Programming
See All in Programming
あなたとKaigi on Rails / Kaigi on Rails + You
shimoju
0
160
Flutterで分数(Fraction)を表示する方法
koukimiura
0
130
なぜGoのジェネリクスはこの形なのか? Featherweight Goが明かす設計の核心
ryotaros
7
1.1k
Things You Thought You Didn’t Need To Care About That Have a Big Impact On Your Job
hollycummins
0
230
Devvox Belgium - Agentic AI Patterns
kdubois
1
120
なぜあの開発者はDevRelに伴走し続けるのか / Why Does That Developer Keep Running Alongside DevRel?
nrslib
3
400
スマホから Youtube Shortsを見られないようにする
lemolatoon
27
32k
理論と実務のギャップを超える
eycjur
0
140
Catch Up: Go Style Guide Update
andpad
0
230
Railsだからできる 例外業務に禍根を残さない 設定設計パターン
ei_ei_eiichi
0
870
タスクの特性や不確実性に応じた最適な作業スタイルの選択(ペアプロ・モブプロ・ソロプロ)と実践 / Optimal Work Style Selection: Pair, Mob, or Solo Programming.
honyanya
3
170
CSC509 Lecture 03
javiergs
PRO
0
340
Featured
See All Featured
Bash Introduction
62gerente
615
210k
Git: the NoSQL Database
bkeepers
PRO
431
66k
The Cost Of JavaScript in 2023
addyosmani
55
9k
Why You Should Never Use an ORM
jnunemaker
PRO
59
9.6k
CSS Pre-Processors: Stylus, Less & Sass
bermonpainter
359
30k
Context Engineering - Making Every Token Count
addyosmani
6
250
Design and Strategy: How to Deal with People Who Don’t "Get" Design
morganepeng
132
19k
The Art of Programming - Codeland 2020
erikaheidi
56
14k
Chrome DevTools: State of the Union 2024 - Debugging React & Beyond
addyosmani
8
910
The Language of Interfaces
destraynor
162
25k
Reflections from 52 weeks, 52 projects
jeffersonlam
353
21k
How STYLIGHT went responsive
nonsquared
100
5.8k
Transcript
System.loadLibrary( “Unix, Native Code and why bother”)
Library static shared static dynamic loading (.o, .a, ...) (.so,
.dll, .dylib, ...)
Program A Program B static libs (.a) static libs (.a)
static linking compile-time
Program A Program B Program A Program B static libs
(.a) static libs (.a) shared libs (.so) static linking dynamic linking compile-time run-time
Library static shared bookstore library Paul Richter
source code compiler
source code compiler objects (.o) .o .o .o .a archive
.o
source code compiler linker objects (.o) .o .o .o .a
archive .o executable .so .so .so .so
source code compiler linker loader objects (.o) .o .o .o
.a archive .o executable in-memory image .so .so .so .so
Building the objects
lib1.c
main.c
Static Libraries
Static Libraries
Shared Libraries: Static Loading
Shared Libraries: Static Loading LD_LIBRARY_PATH
Shared Libraries: Dynamic Loading
main.c
main.c
Android
Kernel Display driver USB driver Camera driver WiFi driver Power
Mgmt. Binder IPC ... Application Framework Apps Home Contacts Dialer Clock Your app 3rd party app ... Activity Manager Window Manager Package Manager Location Manager View System Content Providers ... Libraries Android Runtime (Dalvik/ART) Core Libraries Dalvik Virtual Machine (DVM) Surface Manager OpenGL Media Framework SQLite WebKit SSL ... Bionic
Kernel Display driver USB driver Camera driver WiFi driver Power
Mgmt. Binder IPC ...
Kernel Display driver USB driver Camera driver WiFi driver Power
Mgmt. Binder IPC ... Libraries Surface Manager OpenGL Media Framework SQLite WebKit SSL ... Bionic
Android Bionic
Bionic libc libm libdl Linker libstdc++
Bionic libc libm libdl Linker libstdc++ License Size Speed
Bionic libc libm libdl Linker libstdc++ BSD + Rewritten code
+ Android specific services
Bionic libc libm libdl Linker libstdc++
Bionic libc libm libdl Linker libstdc++ Completely from scratch! dlopen()
dlsym() dlerror() dlclose() {
Bionic libc libm libdl Linker libstdc++
Kernel Display driver USB driver Camera driver WiFi driver Power
Mgmt. Binder IPC ... Libraries Android Runtime (Dalvik/ART) Core Libraries Dalvik Virtual Machine (DVM) Surface Manager OpenGL Media Framework SQLite WebKit SSL ... Bionic
Kernel Display driver USB driver Camera driver WiFi driver Power
Mgmt. Binder IPC ... Application Framework Apps Home Contacts Dialer Clock Your app 3rd party app ... Activity Manager Window Manager Package Manager Location Manager View System Content Providers ... Libraries Android Runtime (Dalvik/ART) Core Libraries Dalvik Virtual Machine (DVM) Surface Manager OpenGL Media Framework SQLite WebKit SSL ... Bionic
Kernel Audio driver Application Framework Apps Your app Media Player
Libraries Android Runtime (Dalvik/ART) Core Libraries Dalvik Virtual Machine (DVM) Media Framework Media Player Audio Flinger libaudio.so JNI dlopen()
System.loadLibrary
System.loadLibrary Runtime.loadLibrary
Runtime.java
Runtime.java
None
None
Win: main.dll Linux: libmain.so Mac: libmain.dylib
None
LD_LIBRARY_PATH
Runtime.java
//TODO Runtime::doLoad Runtime.java
//TODO Runtime::doLoad
//TODO Runtime::doLoad LD_LIBRARY_PATH
ClassLoader search (for application libraries) VM search (for system libraries)
Runtime.java
Workaround for zygote’s LD_LIBRARY_PATH Runtime.java
Runtime.cpp
Native.cpp
Native.cpp
Native.cpp
Kernel Application Framework Apps Your app Runtime.java Libraries Android Runtime
Dalvik Virtual Machine (DVM) Native.cpp Runtime.cpp yourlib.so JNI dlopen()
We learned... • Static vs Shared Libraries • Dynamic Loading
• Library paths (+ difference on android) • Android’s internals ◦ Bionic ◦ Dynamic Loading with Dalvik ◦ System.loadLibrary
Thanks! @juliozynger soundcloud.com/jobs