Android应用程序安装过程源代码分析.docx

Android系统在启动的过程中，会启动一个应用程序管理服务PackageManagerService，这个服务负 责扫描系统中特定的目录，找到里面的应用程序文件，即以Apk为后缀的文件，然后对这些文件进解析， 得到应用程序的相关信息，完成m_init 函数来进一步执行操作。
Step 3.
函数system_init实现在libsystem_server库中，源代码位于 frameworks/base/cmds/system_server/library/ 文件中：
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1・ extern "C" status_t system_init()
{
LOGI("Entered system_init()")；
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5・ sp<ProcessState> proc(ProcessState::self());
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7・ sp<IServiceManager> sm = defaultServiceManager();
LOGI("ServiceManager: %p\n", ());
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sp<GrimReaper> grim = new GrimReaper();
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sm->asBinder()->linkToDeath(grim, grim・get(), 0);
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char propBuf[PROPERTY_VALUE_MAX];
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property_get("", propBuf, "1");
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if (strcmp(propBuf, "1") == 0) {
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// Start the SurfaceFlinger
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SurfaceFlinger::instantiate();
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}
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// Start the sensor service
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SensorService::instantiate();
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// On the simulator, audioflinger et al don't get started the
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// same way as on the device, and we need to start them here
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if (!proc->supportsProcesses()) {
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// Start the AudioFlinger
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AudioFlinger::instantiate();
// Start the media playback service
MediaPlayerService::instantiate();
// Start the camera service
CameraService::instantiate();
// Start the audio policy service
AudioPolicyService::instantiate();
}
// And now start the Android runtime. We have to do this bit
// of nastiness because the Android runtime initialization requires
// some of the core system services to already be started.
// All other servers should just start the Android runtime at
// the beginning of their processes's main(), before calling
// the init function.
LOGI("System server: starting Android runtime・\n");
AndroidRuntime* runtime = AndroidRu