Inside the Android OS

G. Blake Meike is a passionate engineer, code poet, and veteran of more than 10 years of Android development at organizations including D2, Realm, Twitter, and Cyanogen. As a teacher, he has trained hundreds of new Android developers. He is author of several books on Android development, including O'Reilly's bestselling Programming Android and Addison-Wesley's Android Concurrency. He holds a degree in Mathematics and Computer Science from Dartmouth College and lives in the Pacific Northwest. Larry Schiefer is the CTO and co-founder of HIQES, LLC, a mobile platform and app engineering services company. He has made a career out of creating software solutions for mobile, embedded, and desktop systems. He started his career at Motorola working on large area telecommunications systems then moved to startups in the telecommunications, networking, and embedded spaces. Digging into Android's internals was a natural progression with his background in telecommunications, embedded systems, and Linux kernel work. He has traveled around the world training engineers at Intel, Qualcomm, Bose, and others about the internal workings of Android. In addition to being an entrepreneur and technical leader, he continues to stay involved with the development of new software and platform solutions.

Preface      xiii
Chapter 1  Why Android?      1
Adopting Android      1
    Full Stack      2
    Broad Acceptance      2
    Beautiful UI      2
    Linux Based      2
    Powerful Development Environment      3
    Open Source      3
AOSP and Google      5
Other Choices      6
    Micro-Controllers      6
    Other RTOSs      7
Summary      8
Chapter 2  Booting Acme      9
Setting Up a Build Machine      10
Downloading the Code      11
Repo      11
Forking the Source      15
    Android Version Selection      16
    Local Mirror      17
    Hosted Git Repositories      18
    Tree Snapshot      19
Repository Commit Pinning      19
Example: Local Mirror of Forked Repositories      19
Building an Image      24
Device Tools      27
    fastboot      28
    adb      29
Flashing the Device      30
Summary      33
Chapter 3  Getting Started      35
Putting Android in Its Place      35
    Hardware      36
    The Linux Kernel      36
    System Libraries      37
    Applications      38
    The Android Framework      39
The Android Service Model      40
Exploring the Source      43
    Other Sources      44
    What's in the Box?      44
Summary      48
Chapter 4  The Kernel      49
The Linux Kernel      49
    Kernel Process Management      50
    Kernel Memory Management      51
The Android Kernel      53
    Android Kernel Features      54
Building a Kernel      62
    The Build System      63
    Downloading the Source      63
Summary      66
Chapter 5  Platform Security      67
Types of Security      67
Verified Boot      68
Operational Security      69
    Android Software Layers      70
    The Process Sandbox      70
    SE Linux for Android      72
    SE Policy Definition      73
    Android Permissions      76
    File Systems      79
User Protections      82
Customizing Permissions      83
    Sample Custom Permission-Protected App      83
    Sample Custom Permission Client App      88
Summary      92
Chapter 6  System Startup: Installing and Booting the System      93
The Boot Process      93
    Bootloader      95
    Fastboot      99
    Kernel      100
    The File System      102
    init      104
Recovery      106
Building a Daemon      107
Creating the Acme Device      107
Repo Again      110
Starting the Daemon      111
Summary      114
Chapter 7  Android Startup: Dalvik and Zygote      115
Dalvik      116
    ART      120
    ART Basics      120
Hybrid ART      122
Zygote      123
    Zygote Memory Management      123
    Zygote Startup      127
    Runtime Initialization      128
    System Service Startup      129
Summary      131
Citations      131
Chapter 8  Getting to Android: The HAL      133
Why a HAL?      133
Is a HAL Necessary?      135
Designing the HAL      136
Building a HAL      137
    Code Structure      138
    Implementing the HAL      140
Summary      151
Chapter 9  Getting to Java: The JNI      153
Code Structure      154
Using the Device      155
Using the HAL      157
Using the Java Native Interface      159
    Executing Native Code      160
    JNI: The Java Side      161
    JNI: The Native Side      162
    A Java Proximity Application      165
    JNI: Some Hints      176
Summary      182
Chapter 10  Project Treble: Binderized HAL      183
HIDL Architecture      183
    hwservicemanager      185
    HIDL Services      185
    HIDL Client Applications      186
Hardware Interface Definition Language (HIDL)      186
    HIDL Types      191
HIDL Services      194
HIDL Clients      197
Summary      198
Chapter 11  Creating a Custom Binderized HAL      199
Acme Custom HIDL      199
Summary      217
Chapter 12  Clients for a Custom Binderized HAL      219
Native C++ Aproximity Client      219
    SE Linux for Android Changes for aproximitycl      224
    Build aproximitycl into Acme      225
Java/Kotlin Aproximity Client      226
    SE Linux for Android Changes for AproximityClient      229
    Build AproximityClient into Acme      229
Summary      231
Index      233