init.rc语法解析（转载）

1、init.rc是一个可配置的初始化文件,通常定制厂商可以配置额外的初始化配置，init.%PRODUCT%.rc2、init.rc是在$GINGERBREAD/system/core/init/init.c中读取的,它基于“行”，包含一些用空格隔开的关键字（它属于特殊字符）3、如果关键字中有空格，处理方法类似于C语言，使用/表示转义，使用“”防止关键字被断开，另外注意/在末尾表示换行4、#开头的表示注释5、init.rc包含4种状态类别：Actions/Commands/Services/Options6、当声明一个service或者action的时候，它将隐式声明一个section，它之后跟随的command或者option都将属于这个section7、action和service不能重名，否则忽略为error8、actions就是在某种条件下触发一系列的命令，通常有一个trigger，形式如：on <trigger>     <command>     <command>9、service结构如下：service <name> <pathname> [ <argument> ]*     <option>     <option>10、option是service的修饰词，主要包括：   critical     表示如果服务在4分钟内存在多于4次，则系统重启到recovery mode   disabled     表示服务不会自动启动，需要手动调用名字启动   setEnv <name> <value>     设置启动环境变量   socket <name> <type> <permission> [<user> [<group>]]    开启一个unix域的socket，名字为/dev/socket/<name> , <type>只能是dgram或者stream,<user>和<group>默认为0   user <username>    表示将用户切换为<username>,用户名已经定义好了，只能是system/root   group <groupname>    表示将组切换为<groupname>   oneshot    表示这个service只启动一次   class <name>    指定一个要启动的类，这个类中如果有多个service，将会被同时启动。默认的class将会是“default”   onrestart    在重启时执行一条命令11、trigger主要包括：   boot    当/init.conf加载完毕时   <name>=<value>    当<name>被设置为<value>时   device-added-<path>    设备<path>被添加时   device-removed-<path>    设备<path>被移除时   service-exited-<name>    服务<name>退出时12、命令主要包括：   exec <path> [ <argument> ]*   执行一个<path>指定的程序   export <name> <value>   设置一个全局变量   ifup <interface>   使网络接口<interface>连接   import <filename>   引入其他的配置文件   hostname <name>   设置主机名   chdir <directory>   切换工作目录   chmod <octal-mode> <path>   设置访问权限   chown <owner> <group> <path>   设置用户和组   chroot <directory>   设置根目录   class_start <serviceclass>   启动类中的service   class_stop <serviceclass>   停止类中的service   domainname <name>   设置域名   insmod <path>   安装模块   mkdir <path> [mode] [owner] [group]   创建一个目录，并可以指定权限，用户和组   mount <type> <device> <dir> [ <mountoption> ]*   加载指定设备到目录下   <mountoption> 包括"ro", "rw", "remount", "noatime"   setprop <name> <value>   设置系统属性   setrlimit <resource> <cur> <max>   设置资源访问权限   start <service>   开启服务   stop <service>   停止服务   symlink <target> <path>   创建一个动态链接   sysclktz <mins_west_of_gmt>   设置系统时钟   trigger <event>   触发事件   write <path> <string> [ <string> ]*   向<path>路径的文件写入多个<string>

1# Copyright (C) 2012 The Android Open Source Project2# Copyright (C) 3# Copyright (C) 4#5# IMPORTANT: Do not create world writable files or directories.6# This is a common source of Android security bugs.7#89import /init.${ro.hardware}.rc  //import <filename> : 包含其他的*.rc，类似include10import /init.usb.rc11import /init.trace.rc1213on early-init     //最先做 其中的action， 开始early-init 段14    # Set init and its forked children's oom_adj.15    write /proc/1/oom_adj -16  //直接写入procfs1617    start ueventd   //启动一个服务，注意ueventd 必须是一个service,在359行有定义1819# create mountpoints20    mkdir /mnt 0775 root system //创建目录，具体用法与shell中的mkdir命令一样2122on init  //开始init段，其中的action在 early-init,property-init后执行2324sysclktz 0  //设置系统时钟，如果是0表示用GMT的时钟ticks2526loglevel 3  //log的输出级别［0，7］，控制的kernel的log输出2728# setup the global environment 29    export PATH /sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin  //export,shell命令，设置全局环境变量30    export LD_LIBRARY_PATH /vendor/lib:/system/lib31    export ANDROID_BOOTLOGO 132    export ANDROID_ROOT /system33    export ANDROID_ASSETS /system/app34    export ANDROID_DATA /data35    export ASEC_MOUNTPOINT /mnt/asec36    export LOOP_MOUNTPOINT /mnt/obb37    export BOOTCLASSPATH /system/framework/core.jar:/system/framework/core-junit.jar:/system/framework/bouncycastle.jar:/system/framework/ext.jar:/system/framework/framework.jar:/system/framework/framework_ext.jar:/system/framework/android.policy.jar:/system/framework/services.jar:/system/framework/apache-xml.jar3839# Backward compatibility40    symlink /system/etc /etc  //创建一个指向/system/etc的软连接/etc, 也就是/etc目录实际上指向/system/etc41    symlink /sys/kernel/debug /d4243# Right now vendor lives on the same filesystem as system,44# but someday that may change.45    symlink /system/vendor /vendor4647# Create cgroup mount point for cpu accounting48    mkdir /acct49    mount cgroup none /acct cpuacct //mount <type> <device> <dir> ［mountoption］ 把device(none)挂载到type为cgroup 的文件系统/acct下                                      //其中<device>可以是以mtd@name形式指定的一个mtd块设备. mountoption可以是mode=0755,gid=100050    mkdir /acct/uid5152    mkdir /system53    mkdir /data 0771 system system54    mkdir /cache 0770 system cache55    mkdir /config 0500 root root5657    # Directory for putting things only root should see.58    mkdir /mnt/secure 0700 root root5960    # Directory for staging bindmounts61    mkdir /mnt/secure/staging 0700 root root6263    # Directory-target for where the secure container64    # imagefile directory will be bind-mounted65    mkdir /mnt/secure/asec  0700 root root6667    # Secure container public mount points.68    mkdir /mnt/asec  0700 root system69    mount tmpfs tmpfs /mnt/asec mode=0755,gid=10007071    # Filesystem image public mount points.72    mkdir /mnt/obb 0700 root system73    mount tmpfs tmpfs /mnt/obb mode=0755,gid=10007475    write /proc/sys/kernel/panic_on_oops 176    write /proc/sys/kernel/hung_task_timeout_secs 077    write /proc/cpu/alignment 478    write /proc/sys/kernel/sched_latency_ns 1000000079    write /proc/sys/kernel/sched_wakeup_granularity_ns 200000080    write /proc/sys/kernel/sched_compat_yield 181    write /proc/sys/kernel/sched_child_runs_first 082    write /proc/sys/kernel/randomize_va_space 283    write /proc/sys/kernel/kptr_restrict 284    write /proc/sys/kernel/dmesg_restrict 185    write /proc/sys/vm/mmap_min_addr 3276886    write /proc/sys/kernel/sched_rt_runtime_us 95000087    write /proc/sys/kernel/sched_rt_period_us 10000008889# Create cgroup mount points for process groups90    mkdir /dev/cpuctl91    mount cgroup none /dev/cpuctl cpu92    chown system system /dev/cpuctl   //改变目录（/dev/cpuctl）的使用群体为system93    chown system system /dev/cpuctl/tasks94    chmod 0660 /dev/cpuctl/tasks      //改变文件（/dev/cpuctl/tasks）的使用权限为066095    write /dev/cpuctl/cpu.shares 102496    write /dev/cpuctl/cpu.rt_runtime_us 95000097    write /dev/cpuctl/cpu.rt_period_us 10000009899    mkdir /dev/cpuctl/apps100    chown system system /dev/cpuctl/apps/tasks101    chmod 0666 /dev/cpuctl/apps/tasks102    write /dev/cpuctl/apps/cpu.shares 1024103    write /dev/cpuctl/apps/cpu.rt_runtime_us 800000104    write /dev/cpuctl/apps/cpu.rt_period_us 1000000105106    mkdir /dev/cpuctl/apps/bg_non_interactive107    chown system system /dev/cpuctl/apps/bg_non_interactive/tasks108    chmod 0666 /dev/cpuctl/apps/bg_non_interactive/tasks109    # 5.0 %110    write /dev/cpuctl/apps/bg_non_interactive/cpu.shares 52111    write /dev/cpuctl/apps/bg_non_interactive/cpu.rt_runtime_us 700000112    write /dev/cpuctl/apps/bg_non_interactive/cpu.rt_period_us 1000000113114# Allow everybody to read the xt_qtaguid resource tracking misc dev.115# This is needed by any process that uses socket tagging.116    chmod 0644 /dev/xt_qtaguid117118on fs  //??????119# mount mtd partitions120    # Mount /system rw first to give the filesystem a chance to save a checkpoint121    mount yaffs2 mtd@system /system122    mount yaffs2 mtd@system /system ro remount123    mount yaffs2 mtd@userdata /data nosuid nodev124    mount yaffs2 mtd@cache /cache nosuid nodev125126on post-fs127    # once everything is setup, no need to modify /128    mount rootfs rootfs / ro remount129130    # We chown/chmod /cache again so because mount is run as root + defaults131    chown system cache /cache132    chmod 0770 /cache133134    # This may have been created by the recovery system with odd permissions135    mkdir /cache/recovery136    chown system cache /cache/recovery137    chmod 0770 /cache/recovery138139    #change permissions on vmallocinfo so we can grab it from bugreports140    chown root log /proc/vmallocinfo141    chmod 0440 /proc/vmallocinfo142143    #change permissions on kmsg & sysrq-trigger so bugreports can grab kthread stacks144    chown root system /proc/kmsg145    chmod 0440 /proc/kmsg146    chown root system /proc/sysrq-trigger147    chmod 0220 /proc/sysrq-trigger148149    # create the lost+found directories, so as to enforce our permissions150    # Moved to init.target.rc in the Sony product git151    # mkdir /cache/lost+found 0770 root root152153on post-fs-data154    # We chown/chmod /data again so because mount is run as root + defaults155    chown system system /data156    chmod 0771 /data157158    # Create dump dir and collect dumps.159    # Do this before we mount cache so eventually we can use cache for160    # storing dumps on platforms which do not have a dedicated dump partition.161    mkdir /data/dontpanic 0750 root log162163    # Collect apanic data, free resources and re-arm trigger164    copy /proc/apanic_console /data/dontpanic/apanic_console165    chown root log /data/dontpanic/apanic_console166    chmod 0640 /data/dontpanic/apanic_console167168    copy /proc/apanic_threads /data/dontpanic/apanic_threads169    chown root log /data/dontpanic/apanic_threads170    chmod 0640 /data/dontpanic/apanic_threads171172    write /proc/apanic_console 1173174    # create basic filesystem structure175    mkdir /data/misc 01771 system misc176    mkdir /data/misc/bluetoothd 0770 bluetooth bluetooth177    mkdir /data/misc/bluetooth 0770 system system178    mkdir /data/misc/keystore 0700 keystore keystore179    mkdir /data/misc/keychain 0771 system system180    mkdir /data/misc/vpn 0770 system vpn181    mkdir /data/misc/systemkeys 0700 system system182    # give system access to wpa_supplicant.conf for backup and restore183    mkdir /data/misc/wifi 0770 wifi wifi184    chmod 0660 /data/misc/wifi/wpa_supplicant.conf185    mkdir /data/local 0751 root root186    chmod 2770 /data/radio187188    # For security reasons, /data/local/tmp should always be empty.189    # Do not place files or directories in /data/local/tmp190    mkdir /data/local/tmp 0771 shell shell191    mkdir /data/data 0771 system system192    mkdir /data/app-private 0771 system system193    mkdir /data/app-asec 0700 root root194    mkdir /data/app 0771 system system195    mkdir /data/property 0700 root root196    mkdir /data/ssh 0750 root shell197    mkdir /data/ssh/empty 0700 root root198199    # create dalvik-cache, so as to enforce our permissions200    mkdir /data/dalvik-cache 0771 system system201202    # create resource-cache and double-check the perms203    mkdir /data/resource-cache 0771 system system204    chown system system /data/resource-cache205    chmod 0771 /data/resource-cache206207    # create the lost+found directories, so as to enforce our permissions208    # Moved to init.target.rc in the Sony product git209    # mkdir /data/lost+found 0770 root root210211    # create directory for DRM plug-ins - give drm the read/write access to212    # the following directory.213    mkdir /data/drm 0770 drm drm214215    # If there is no fs-post-data action in the init.<device>.rc file, you216    # must uncomment this line, otherwise encrypted filesystems217    # won't work.218    # Set indication (checked by vold) that we have finished this action219    #setprop vold.post_fs_data_done 1220221on boot //开始boot段，其中的action在 early-init,property-init,init后执行222# basic network init223    ifup lo                 //启动网路接口 lo, 但lo是啥接口？224    hostname localhost      //设置手机主机名为localhost225    domainname localdomain  //设置域名localdomain226227# set RLIMIT_NICE to allow priorities from 19 to -20228    setrlimit 13 40 40229230# Memory management.  Basic kernel parameters, and allow the high231# level system server to be able to adjust the kernel OOM driver232# parameters to match how it is managing things.233    write /proc/sys/vm/overcommit_memory 1234    write /proc/sys/vm/min_free_order_shift 4235    chown root system /sys/module/lowmemorykiller/parameters/adj236    chmod 0664 /sys/module/lowmemorykiller/parameters/adj237    chown root system /sys/module/lowmemorykiller/parameters/minfree238    chmod 0664 /sys/module/lowmemorykiller/parameters/minfree239240    # Tweak background writeout241    write /proc/sys/vm/dirty_expire_centisecs 200242    write /proc/sys/vm/dirty_background_ratio  5243244    # Permissions for System Server and daemons.245    chown radio system /sys/android_power/state246    chown radio system /sys/android_power/request_state247    chown radio system /sys/android_power/acquire_full_wake_lock248    chown radio system /sys/android_power/acquire_partial_wake_lock249    chown radio system /sys/android_power/release_wake_lock250    chown system system /sys/power/state251    chown system system /sys/power/autosleep252    chown system system /sys/power/wakeup_count253    chown radio system /sys/power/wake_lock254    chown radio system /sys/power/wake_unlock255    chmod 0660 /sys/power/state256    chmod 0660 /sys/power/wake_lock257    chmod 0660 /sys/power/wake_unlock258259    chown system system /sys/devices/system/cpu/cpufreq/interactive/timer_rate260    chmod 0660 /sys/devices/system/cpu/cpufreq/interactive/timer_rate261    chown system system /sys/devices/system/cpu/cpufreq/interactive/min_sample_time262    chmod 0660 /sys/devices/system/cpu/cpufreq/interactive/min_sample_time263    chown system system /sys/devices/system/cpu/cpufreq/interactive/hispeed_freq264    chmod 0660 /sys/devices/system/cpu/cpufreq/interactive/hispeed_freq265    chown system system /sys/devices/system/cpu/cpufreq/interactive/go_hispeed_load266    chmod 0660 /sys/devices/system/cpu/cpufreq/interactive/go_hispeed_load267    chown system system /sys/devices/system/cpu/cpufreq/interactive/above_hispeed_delay268    chmod 0660 /sys/devices/system/cpu/cpufreq/interactive/above_hispeed_delay269    chown system system /sys/devices/system/cpu/cpufreq/interactive/boost270    chmod 0660 /sys/devices/system/cpu/cpufreq/interactive/boost271    chown system system /sys/devices/system/cpu/cpufreq/interactive/boostpulse272    chown system system /sys/devices/system/cpu/cpufreq/interactive/input_boost273    chmod 0660 /sys/devices/system/cpu/cpufreq/interactive/input_boost274275    # Assume SMP uses shared cpufreq policy for all CPUs276    chown system system /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq277    chmod 0660 /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq278279    chown system system /sys/class/timed_output/vibrator/enable280    chown system system /sys/class/leds/keyboard-backlight/brightness281    chown system system /sys/class/leds/lcd-backlight/brightness282    chown system system /sys/class/leds/button-backlight/brightness283    chown system system /sys/class/leds/jogball-backlight/brightness284    chown system system /sys/class/leds/red/brightness285    chown system system /sys/class/leds/green/brightness286    chown system system /sys/class/leds/blue/brightness287    chown system system /sys/class/leds/red/device/grpfreq288    chown system system /sys/class/leds/red/device/grppwm289    chown system system /sys/class/leds/red/device/blink290    chown system system /sys/class/leds/red/brightness291    chown system system /sys/class/leds/green/brightness292    chown system system /sys/class/leds/blue/brightness293    chown system system /sys/class/leds/red/device/grpfreq294    chown system system /sys/class/leds/red/device/grppwm295    chown system system /sys/class/leds/red/device/blink296    chown system system /sys/class/timed_output/vibrator/enable297    chown system system /sys/module/sco/parameters/disable_esco298    chown system system /sys/kernel/ipv4/tcp_wmem_min299    chown system system /sys/kernel/ipv4/tcp_wmem_def300    chown system system /sys/kernel/ipv4/tcp_wmem_max301    chown system system /sys/kernel/ipv4/tcp_rmem_min302    chown system system /sys/kernel/ipv4/tcp_rmem_def303    chown system system /sys/kernel/ipv4/tcp_rmem_max304    chown root radio /proc/cmdline305306# Define TCP buffer sizes for various networks307#   ReadMin, ReadInitial, ReadMax, WriteMin, WriteInitial, WriteMax,308    setprop net.tcp.buffersize.default 4096,87380,110208,4096,16384,110208309    setprop net.tcp.buffersize.wifi    524288,1048576,2097152,262144,524288,1048576310    setprop net.tcp.buffersize.lte     524288,1048576,2097152,262144,524288,1048576311    setprop net.tcp.buffersize.umts    4094,87380,110208,4096,16384,110208312    setprop net.tcp.buffersize.hspa    4094,87380,1220608,4096,16384,1220608313    setprop net.tcp.buffersize.hsupa   4094,87380,1220608,4096,16384,1220608314    setprop net.tcp.buffersize.hsdpa   4094,87380,1220608,4096,16384,110208315    setprop net.tcp.buffersize.hspap   4094,87380,2097152,4096,16384,1220608316    setprop net.tcp.buffersize.edge    4093,26280,35040,4096,16384,35040317    setprop net.tcp.buffersize.gprs    4092,8760,11680,4096,8760,11680318    setprop net.tcp.buffersize.evdo_b  4094,87380,262144,4096,16384,262144319320# Assign TCP buffer thresholds to be ceiling value of technology maximums321# Increased technology maximums should be reflected here.322    write /proc/sys/net/core/rmem_max  2097152323    write /proc/sys/net/core/wmem_max  1220608324325# Set this property so surfaceflinger is not started by system_init326    setprop system_init.startsurfaceflinger 0327328    class_start core  //如果所有的class类别为core 的服务没有运行，则马上启动它们329    class_start main330331on nonencrypted332    class_start late_start333334on charger335    class_start charger336337on property:vold.decrypt=trigger_reset_main338    class_reset main339340on property:vold.decrypt=trigger_load_persist_props341    load_persist_props342343on property:vold.decrypt=trigger_post_fs_data344    trigger post-fs-data   //触发一个事件post-fs-data， 该事件是用on post-fs-data定义的，位于后面345346on property:vold.decrypt=trigger_restart_min_framework347    class_start main348349on property:vold.decrypt=trigger_restart_framework350    class_start main351    class_start late_start352353on property:vold.decrypt=trigger_shutdown_framework354    class_reset late_start355    class_reset main356357## Daemon processes to be run by init.358##359service ueventd /sbin/ueventd  //表示service段，语法: service <服务名字> <服务对应的执行文件>; 声明服务名字为ueventd的服务，其具体执行路径                                  //为/sbin/ueventd360    class core                 //表示属于class 类别为core 的服务,如果没有设置，则表示该服务的默认类别为default361    critical                   //362363service console /system/bin/sh364    class core365    console366    disabled367    user shell368    group log369370on property:ro.debuggable=1    //如果用setprop命令设置属性 ro.debuggable变成1,则触发下面的start console371    start console372373# adbd is controlled via property triggers in init.<platform>.usb.rc374service adbd /sbin/adbd375    class core376    disabled      //该服务不能通过启动一类服务来启动，比如 class_start core来启动，只能以单独的名字来启动 start adbd.377378# adbd on at boot in emulator379on property:ro.kernel.qemu=1380    start adbd381382service servicemanager /system/bin/servicemanager383    class core384    user system        //在该服务启动前，把用户名切换到 system,默认是root385    group system       //在该服务启动前，把组名切换到 system.386    critical           //说明该服务是个对于设备很关键的服务，如果4分钟内退出大于4次，则系统将重启并进入recovery恢复模式387    onrestart exec /system/bin/sync  //当该服务重启时，执行后面的命令 exec                                     //exec创建和执行一个程序（/system/bin/sync），在程序完全执行完之前，init会被阻塞。所以极有可能引起init卡死388    onrestart write /proc/sysrq-trigger c389390service vold /system/bin/vold391    class core392    socket vold stream 0660 root mount //语法：socket <name> <type> <perm> <user> <group>, 创建一个名字为vold<name>,类别为stream<type>                                          //访问权限为0660<perm> 用户为root,用户组为mount393    ioprio be 2394395service netd /system/bin/netd396    class main397    socket netd stream 0660 root system398    socket dnsproxyd stream 0660 root inet399    socket mdns stream 0660 root system400401service debuggerd /system/bin/debuggerd402    class main403404service ril-daemon /system/bin/rild405    class main406    socket rild stream 660 root radio407    socket rild-debug stream 660 radio system408    user root409    group radio cache inet misc audio sdcard_r sdcard_rw qcom_oncrpc diag qcom_diag log410411service surfaceflinger /system/bin/surfaceflinger412    class main413    user system414    group graphics415    onrestart exec /system/bin/sync416    onrestart write /proc/sysrq-trigger c417418service zygote /system/bin/app_process -Xzygote /system/bin --zygote --start-system-server419    class main420    socket zygote stream 660 root system421    onrestart exec /system/bin/sync422    onrestart write /proc/sysrq-trigger c423424service drm /system/bin/drmserver425    class main426    user drm427    group drm system inet drmrpc sdcard_r428429service media /system/bin/mediaserver430    class main431    user media432    group system audio camera inet net_bt net_bt_admin net_bw_acct drmrpc input qcom_diag433    ioprio rt 4434435service bootanim /system/bin/bootanimation436    class main437    user graphics438    group graphics439    disabled440    oneshot    //该服务只启动一次，退出后不再运行441442service dbus /system/bin/dbus-daemon --system --nofork443    class main444    socket dbus stream 660 bluetooth bluetooth445    user bluetooth446    group bluetooth net_bt_admin447448service bluetoothd /system/bin/logwrapper /system/bin/bluetoothd -n449    class main450    socket bluetooth stream 660 bluetooth bluetooth451    socket dbus_bluetooth stream 660 bluetooth bluetooth452    # init.rc does not yet support applying capabilities, so run as root and453    # let bluetoothd drop uid to bluetooth with the right linux capabilities454    group bluetooth net_bt_admin misc455    disabled456457service installd /system/bin/installd458    class main459    socket installd stream 600 system system460461service flash_recovery /system/etc/install-recovery.sh462    class main463    oneshot464465service racoon /system/bin/racoon466    class main467    socket racoon stream 600 system system468    # IKE uses UDP port 500. Racoon will setuid to vpn after binding the port.469    group vpn net_admin inet470    disabled471    oneshot472473service mtpd /system/bin/mtpd474    class main475    socket mtpd stream 600 system system476    user vpn477    group vpn net_admin inet net_raw478    disabled479    oneshot480481service keystore /system/bin/keystore /data/misc/keystore482    class main483    user keystore484    group keystore drmrpc485    socket keystore stream 666486487service dumpstate /system/bin/dumpstate -s488    class main489    socket dumpstate stream 0660 shell log490    disabled491    oneshot492493service sshd /system/bin/start-ssh494    class main495    disabled496497service mdnsd /system/bin/mdnsd498    class main499    user mdnsr500    group inet net_raw501    socket mdnsd stream 0660 mdnsr inet502    disabled503    oneshot504

init.rc语法介绍
实例分析init.rc的语法