Android IPC Mechanism

URL : http://www.slideshare.net/jserv/android-ipc-mechanism

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(0) IPC: The heart of Android

(1) Design Patterns

(2) Binder IPC Internals

(3) Use case: Graphics

Binder IPC: The heart of Android

Android Tasks

Component View

Why IPC?

• Each process has its own address space

• Provides data isolation

• Prevents harmful direct interaction between two 

different processes

– Sometimes, communication between processes is required for modularization

IPC Mechanisms

• In GNU/Linux

– Signal

– Pipe

– Socket

– Semaphore

– Message queue

– Shared memory

• In Android

– Binder: lightweight RPC (Remote Procedure Communication) mechanism

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Design Patterns

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Design Patterns used in Binder (incomplete)

• Proxy Pattern

• Mediator Pattern

• Bridge Pattern

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Binder Internals

Binder Terminology

Binder

• Binder Object

– an instance of a class that implements the Binder interface.

– One Binder object can implement multiple Binders

• Binder Protocol

• IBinder Interface

– is a well-defined set of methods, properties and events that a Binder can implement.

• Binder Token

– A numeric value that uniquely identifies a Binder

Facilities

Simple inter process messaging system

• Managing

• Identifying

• Calls

• Notification

• Binder as a security access token

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Get Service list from SM

$ adb shell service list

Found 71 services:

0 stub_isms: [com.android.internal.telephony.ISms]

1 stub_phone: [com.android.internal.telephony.ITelephony]

2 stub_iphonesubinfo: [com.android.internal.telephony.IPhoneSubInfo]

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5 stub_telephony.registry: [com.android.internal.telephony.ITelephonyRegistry]

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7 stub_activity: [android.app.IActivityManager]

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9 phone: [com.android.internal.telephony.ITelephony]

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56 activity: [android.app.IActivityManager]

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64 SurfaceFlinger: [android.ui.ISurfaceComposer]

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android-binder-120321103105-phpapp01.pdf