Android初始化流程简要分析.docx

1、Android初始化流程简要分析Android初始化流程简要分析 liranke TABLE OF CONTENTS1 Init process 21.1 Main function（引自sdk参考文档） 21.1.1 Process step: 21.1.2 Start services: 31.2 Flow chart： 41.2.1 Flow chart: 41.3 Analyse： 51.3.1 FD: 51.4 System status 71.4.1 rocess list 72 Adbd 93 Servicemanager 93.1 Introcuce 93.2 Compiler

2、 103.3 Flow: 103.3.1 Main of Frameworksbasecmdsservicemanagerservice_manager.c 103.4 Main_runtimer.cpp 164 Mountd 174.1 Analyse 175 Debuggerd 185.1 Chart 186 Rild 186.1 Chart 186.1.1 RIL Architecture: 186.1.2 RIL Flow: 197 zygote 207.1 Introduce 207.2 app_process 217.2.1 compile: 217.2.2 Class chart

3、: 227.2.3 Flow chart: 227.3 ZygoteInit 247.3.1 compile: 247.3.2 ZygoteInit Main function flow chart 248 system_server 268.1 Compile: 268.2 Analyse: 278.2.1 Server Class chart 278.2.2 Syste_init 288.2.3 startSystemServer 298.2.4 runSelectLoopMode 298.2.5 context = ActivityManagerService.main(factoryT

4、est)的执行过程 369 Media 3810 Bootsound 3811 Dbus 3812 Installd 3812.1 Chart 3812.2 Analyse 391 Init processInit is the first process after kernel is started. Init code local at system/core/init(Android) dir, main function is included init.c. Init is called by kernel_init function localling at init(kerne

5、l) dir, via execve function.1.1 Main function（引自sdk参考文档）Init is the first process after kernel is started. Init code local at system/core/init(Android) dir, main function is included init.c. Init is called by kernel_init function localling at init(kernel) dir, via execve function.1.1.1 Process step:

6、1. Mount basic file system, and nitialize log system. 2. Parse /init.rc and /init.%hardware%.rc. 3. Execute early-init action in init.rc. 4. Device specific initialize. 5. Initialize property system, and load android image, then print” ANDROID”. 6. Execute init action in init.rc. 7. Start property s

7、ervice. 8. Execute early-boot and boot actions in init.rc. 9. Execute property action in init.rc. 10. Enter into an indefinite loop to wait for device/property set/child process exit events. For example, if an SD card is plugined, init will receive a device add event, so it can make node for the dev

8、ice. Most of the important process is forked in init, so if any of them crashed, init will receive a SIGCHLD then translate it into a child process exit event, so in the loop init can handle the process exit event and execute the commands defined in *.rc(it will run command onrestart). 1.1.2 Start s

9、ervices:The .rc file is a script file defined by Android. The default is device/system/rootdir/init.rc. We can take a loot at the file format(device/system/init/readme.txt is a good overall introduction of the script). Basically the script file contains actions and services. Init.rc will run the fol

10、lowing services:console: star a shell. The source is in device/system/bin/sh. adbd: start adb daemon. The source is in device/tools/adbd. By default is disabled. servicemanager: start binder system. The source is in device/commands/binder. mountd: mount all fs defined in /system/etc/mountd.conf if s

11、tarted, receive commands through local socket to mount any fs. The source is in device/system/bin/mountd. debuggerd: start debug system. The source is in device/system/bin/debuggerd. rild: start radio interface layer daemon. The source is in device/commands/rild. zygote: start Android Java Runtime a

12、nd start system server. Its the most important service. The source is in device/servers/app. media: start AudioFlinger, MediaPlayerService and CameraService. The source is in device/commands/mediaserver. bootsound: play the default boot sound /system/media/audio/ui/boot.mp3. The source is in device/

13、commands/playmp3. dbus: start dbus daemon, its only used by BlueZ. The source is in device/system/Bluetooth/dbus-daemon. hcid: redirect hcids stdout and stderr to the Android logging system. The source is in device/system/bin/logwrapper. By default is disabled. hfag: start Bluetooth handsfree audio

14、gateway, its only used by BlueZ. The source is in device/system/Bluetooth/bluez-utils. By default is disabled. hsag: start Bluetooth headset audio gateway, its only used by BlueZ. The source is in device/system/Bluetooth/bluez-utils. By default is disabled. installd: start install package daemon. Th

15、e source is in device/servers/installd. flash_recovery: load /system/recovery.img. The source is in device/commands/recovery/mtdutils.1.2 Flow chart：1.2.1 Flow chart:1.3 Analyse：1.3.1 FD: FD Include : device _fd, property_set_fd, signal_recv_fd, signal_fd(global value) ufds: struct pollfd ufds4 = de

16、vice _fd , property_set_fd , signal_recv_fd , keychord_fd 1. device_fd 2. property_set_fd(1) (2) Property_set_fd C/S chart:#define PROP_SERVICE_NAME property_service3. signal_recv_fdsignal_recv_fd and signal_fd:/* create a signalling mechanism for the sigchld handler */ if (socketpair(AF_UNIX, SOCK_

17、STREAM, 0, s) = 0) signal_fd = s0; signal_recv_fd = s1; fcntl(s0, F_SETFD, FD_CLOEXEC); fcntl(s0, F_SETFL, O_NONBLOCK); fcntl(s1, F_SETFD, FD_CLOEXEC); fcntl(s1, F_SETFL, O_NONBLOCK); /read signalread(signal_recv_fd, tmp, sizeof(tmp);while (!wait_for_one_process(0); /阻塞4. signal_fd( see to signal_re

18、cv_fd)1.4 System status1.4.1 rocess list USER PID PPID VSIZE RSS WCHAN PC NAMEroot 1 0 548 196 c00b8c14 0000d5cc S /initroot 2 0 0 0 c006bf70 00000000 S kthreaddroot 3 2 0 0 c005cc50 00000000 S ksoftirqd/0root 4 2 0 0 c007e408 00000000 S watchdog/0root 5 2 0 0 c0068eec 00000000 S events/0root 6 2 0

19、0 c0068eec 00000000 S khelperroot 10 2 0 0 c0224f90 00000000 S suspend/0root 81 2 0 0 c0068eec 00000000 S kblockd/0root 89 2 0 0 c01f2f7c 00000000 S kseriodroot 111 2 0 0 c0068eec 00000000 S kmmcdroot 117 2 0 0 c0068eec 00000000 S btaddconnroot 118 2 0 0 c0068eec 00000000 S btdelconnroot 135 2 0 0 c

20、00448e0 00000000 S bpmdroot 141 2 0 0 c008b5f4 00000000 S pdflushroot 142 2 0 0 c008b5f4 00000000 S pdflushroot 143 2 0 0 c008f948 00000000 S kswapd0root 189 2 0 0 c0068eec 00000000 S aio/0root 195 2 0 0 c01721f0 00000000 S mtdblockdroot 340 2 0 0 c01b4eb0 00000000 S accessory notifroot 349 2 0 0 c0

21、068eec 00000000 S camera_task/0root 376 2 0 0 c0061438 00000000 S w1_controlroot 378 2 0 0 c0061438 00000000 S w1_bus_master1root 386 2 0 0 c0068eec 00000000 S charge ?root 428 2 0 0 c02ca26c 00000000 S krfcommdroot 430 2 0 0 c0068eec 00000000 S rpciod/0root 724 2 0 0 c0216908 00000000 S mmcqdroot 7

22、26 1 772 180 c019dbc4 afe0c1dc S /system/bin/shsystem 727 1 840 188 c022d8a0 afe0c47c S /system/bin/servicemanagerroot 729 1 1920 336 ffffffff afe0c1dc S /system/bin/mountdroot 730 1 704 176 c0257854 afe0ce0c S /system/bin/debuggerdroot 731 1 4132 628 c027e2f8 afe0ce0c S /opl/bin/tcmdroot 732 1 852

23、248 c00b92b0 afe0c5a4 S /opl/bin/adapterradio 733 1 12796 648 ffffffff beaab18c S /system/bin/rildroot 734 1 72000 14172 c00b92b0 afe0c5a4 S zygoteroot 735 1 33848 4512 ffffffff afe0c47c S /system/bin/mediaserverroot 736 1 1080 216 c00b8c14 bedc021c S /system/bin/dbus-daemonroot 737 1 832 208 c02b6e

24、80 afe0c1dc S /system/bin/installdroot 740 1 856 260 c00b92b0 afe0c5a4 S /opl/bin/bpdroot 741 1 828 172 c00b8c14 afe0d27c S /opl/bin/battmondroot 768 1 720 272 c02265ec afe0c1dc S /system/bin/logcatroot 769 1 716 264 c02265ec afe0c1dc S /system/bin/logcatroot 816 2 0 0 c0068eec 00000000 S battery.0s

25、ystem 825 734 574128 28360 ffffffff afe0c47c S system_serverradio 877 734 158260 20040 ffffffff afe0d404 S com.android.phoneapp_5 879 734 100888 13616 ffffffff afe0d404 S android.process.acoresystem 882 734 144664 24296 ffffffff afe0d404 S android.process.omsserviceapp_45 884 734 92304 10932 fffffff

26、f afe0d404 S com.motorola.motohomeapp_22 890 734 117068 30228 ffffffff afe0d404 S oms.homeapp_3 918 734 98760 12652 ffffffff afe0d404 S oms.widgetmanagerapp_5 928 734 100888 13336 ffffffff afe0d404 S com.android.inputmethod.borqsapp_24 930 734 105176 19168 ffffffff afe0d404 S com.db4o.servo.searchap

27、p_18 960 734 104180 15208 ffffffff afe0d404 S com.android.mmsapp_8 979 734 118860 14044 ffffffff afe0d404 S android.process.mediaapp_9 991 734 91980 12264 ffffffff afe0d404 S com.android.alarmclockapp_15 998 734 103144 12908 ffffffff afe0d404 S oms.dcdsystem 1018 734 94732 13792 ffffffff afe0d404 S

28、oms.dmapp_14 1025 734 95636 13036 ffffffff afe0d404 S com.android.calendarapp_42 1041 734 93292 11316 ffffffff afe0d404 S com.motorola.smsautoregapp_40 1090 734 97152 15192 ffffffff afe0d404 S com.motorola.mtcapp_38 1102 734 93832 12868 ffffffff afe0d404 S com.streamezzo.browser.androidapp_26 1115 7

29、34 96596 15084 ffffffff afe0d404 S oms.mediacenterapp_37 1126 734 98208 15212 ffffffff afe0d404 S com.hyfsoft.docviewerapp_20 1146 734 99260 15320 ffffffff afe0d404 S com.android.musicapp_47 1157 734 100204 15964 ffffffff afe0d404 S com.motorola.cameraapp_11 1183 734 122672 23576 ffffffff afe0d404 S

30、 com.android.browserapp_6 1199 734 117032 20388 ffffffff afe0d404 S oms.mobilemusicsystem 1244 734 99292 15940 ffffffff afe0d404 S com.android.settingsapp_23 1311 734 96932 16004 ffffffff afe0d404 S oms.bruroot 1334 2 0 0 c0216908 00000000 S mmcqdapp_8 1351 734 100308 15876 ffffffff afe0d404 S com.a

31、ndroid.cameraapp_1 1424 734 111904 17024 ffffffff afe0d404 S oms.messagingapp_4 1436 734 101172 15504 ffffffff afe0d404 S oms.mailapp_2 1484 734 100716 18128 ffffffff afe0d404 S com.msapp_16 1663 734 101024 16748 ffffffff afe0d404 S oms.android.filemanagerroot 1684 1 3364 176 ffffffff 0000e8f4 S /sbin/adbdroot 1692 1684 776 348 c0059cd4 afe0d0ac S /system/bin/shroot 1724 1692 920 356 00000000 afe0c1dc R ps从真正的应用层的角度来看，所有的应用程序（如settings,media）的父进程都是zygote. 因为任何一个应用都是一个VM。2 AdbdSee to A