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About
● Author of:
● Introduced Linux Trace Toolkit in 1999● Originated Adeos and relayfs (kernel/relay.c)● Ara Android Arch Oversight● Training, Custom Dev, Consulting, ...
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Agenda
1. A bit of history
2. Architecture
3. Source layout
4. User-space
5. Services / Daemons
6. Weave
7. Example
8. Summing up
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1. A bit of history
● Embedded Linux● Android● Headless Android● Brillo
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1.1. Embedded Linux
● A set of ad-hoc methods to package the Linux kernel with a (minimal) filesystem.
● FS content “to be determined” case-by-case● APIs are specific to each device/build● “Core software”:
● BusyBox● U-Boot● GNU Toolchain
● Your flavor of:● glibc or uClibc or eglibc● yocto or buildroot or eldk or ltib or ptxdist or ...
● No serious UX framework
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1.2. Android● ... apart from its ubiquitous UX ...● Fully-integrated IDE: Android Studio● SDK/NDK● ADB● Fastboot● Published, well-known, and very rich APIs● A large and growing developer community● And still we can use “embedded Linux” components:
● GNU toolchain, BusyBox, u- boot, glibc, ...
An actual standardized dev. env. across all product lines
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1.3. Headless Android
+ =
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1.4. Brillo / Weave
● Google platform for IoT*● Based on Android● Announced at Google I/O 2015● Still not officially released● Still under active development● Need to sign up for developer preview on https://developers.google.com/brillo/● Sources available from android.googlesource.com
● Note:● This talk based on sources● This talk NOT based on developer preview or any information thereof :P
* New, hip way of talking about “Embedded Systems”, something that's been around for ~50+ years.
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2. Architecture
● Embedded Linux● Android● Binder● System services● HAL● DBus● Brillo● Weave
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/frameworks/base/services/java/...
/frameworks/base/services/jni/
/hardware/libhardware/
/device/[MANUF.]/[DEVICE]/sdk/emulator/
Kernel or module
/frameworks/base/core/...
AOSP-providedASL
Manuf.-providedManuf. license
Manuf.-providedGPL-license
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3. Source layout
● Brillo top level● Removed from Android top level● Gone from external/● New to external
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3.1. Brillo top level
bionic C library replacementbootable Reference bootloaderbuild Build systemdevice Device-specific files and componentsexternal Copy of external projects used by AOSPframeworks Native system services and librarieshardware Hardware support libslibnativehelper JNI helpersprebuilts Prebuilt binariesproduct “Products” running on Brillosystem Embedded Linux coretools Brillo Development Kit
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3.2. Removed from Android top level
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3.3. Gone from external/
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3.4. New to external/
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4. User Space
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5. Services / Daemons● dbus-daemon● servicemanager● avahi-daemon● keystore● nativeperms● peripheralman● sensorservice● wpa_supplicant● brilloaudioservice● metrics_collector● metriscsd● perfprofd● tlsdated● tpm_managerd● trunksd● update_engine● weaved● webservd● shill● firewalld● dhcpd
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6. Weave
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7. Example
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8. Summing Up
● Cool use of AOSP● The “new standard” Embedded Linux distro?
● Yocto● Buildroot
● Work in progress● Nice move to Binder (instead of DBus)● Clear cloud component
