此文来自于对http://source.android.com/porting/index.html中bring up段的简译。其中有一处与源码的
system/core/init/readme.txt（此文也是对init.rc 的解释）内容不同：
socket <name> <type> <perm> [ <user> [ <group> ] ]
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Debugging notes
---------------
By default, programs executed by init will drop stdout and stderr into
/dev/null. To help with debugging, you can execute your program via the
Andoird program logwrapper. This will redirect stdout/stderr into the
Android logging system (accessed via logcat).
For example
service akmd /system/bin/logwrapper /sbin/akmd
注2：讲述了一个新的命令---------------
By default, programs executed by init will drop stdout and stderr into
/dev/null. To help with debugging, you can execute your program via the
Andoird program logwrapper. This will redirect stdout/stderr into the
Android logging system (accessed via logcat).
For example
service akmd /system/bin/logwrapper /sbin/akmd
sysclktz <mins_west_of_gmt>
Set the system clock base (0 if system clock ticks in GMT)
Set the system clock base (0 if system clock ticks in GMT)
注3：triggers
boot
This is the first trigger that will occur when init starts
(after /init.conf is loaded)
<name>=<value>
Triggers of this form occur when the property <name> is set
to the specific value <value>.
device-added-<path>
device-removed-<path>
Triggers of these forms occur when a device node is added
or removed.
service-exited-<name>
Triggers of this form occur when the specified service exits.
This is the first trigger that will occur when init starts
(after /init.conf is loaded)
<name>=<value>
Triggers of this form occur when the property <name> is set
to the specific value <value>.
device-added-<path>
device-removed-<path>
Triggers of these forms occur when a device node is added
or removed.
service-exited-<name>
Triggers of this form occur when the specified service exits.
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init 由如下四种类型语句组成：
- Actionn ：行为
- Commands
- Services
- Options
- 每一个语句占据一行，并且各个关键字被空格分开。c规范中的（如 \n）反斜杠将被忽略(backslash escapes)而被认为是一个空格 ，双引号用来保证空格不会把一个文字串分分为多个关键字。行最后的反斜杠用作续行。
- 由 # （前面允许有空格）开始的行都是注释行(comment)
- 一个actions 或 services 的开始隐含声明了一个新的段，所有commands 或 options 属于最近的声明。在第一个段之前的 commands 或 options 都会被忽略
- 每一个actions 和 services 都有不同的名字。后面与前面发生重名的，那么这个后面重名的将被忽略或被认为是一个错误
Actions其实就是一组被命名的命令序列。actions 都有一个触发条件，触发条件决定了action何时执行。当一个事件发生如果匹配action的触发条件，那么这个action将会被添加到预备执行队列的尾部（除非它已经在队列当中）
每一个action中的命令将被顺序执行。init进程负责在其它activities（如：设备创建/销毁，属性设置，进程重启）之间执行这些命令序列。
Services
services 是一些由init 启动 和 重新（如果有需要）启动的程序，当然这些程序如果是存在的。
Options
options 是service的修饰符，用来告诉init 怎样及何时启动service。
| Option | Description |
|---|---|
disabled | This service will not automatically start with its class. It must be explicitly started by name. |
socket <type> <name> <perm> [ <user> [ <group> ] ] | Create a unix domain socket named |
user <username> | Change to username before exec'ing this service. Currently defaults to root. |
group <groupname> [ <groupname> ]* | Change to groupname before exec'ing this service. Additional groupnames beyond the first, which is required, are used to set additional groups of the process (with setgroups()). Currently defaults to root. |
capability [ <capability> ]+ | Set linux capability before exec'ing this service |
oneshot | Do not restart the service when it exits. |
class <name> | Specify a class name for the service. All services in a named class must start and stop together. A service is considered of class "default" if one is not specified via the class option. |
Triggers
Triggers are strings used to match certain kinds of events that cause an action to occur.
| Trigger | Description |
|---|---|
boot | This is the first trigger that occurs when init starts (after /init.conf is loaded). |
<name>=<value> | Triggers of this form occur when the property <name> is set to the specific value <value>. |
device-added-<path> | Triggers of these forms occur when a device node is added or removed. |
service-exited-<name> | Triggers of this form occur when the specified service exits. |
Commands
| Command | Description |
|---|---|
exec <path> [ <argument> ]* | Fork and execute a program (<path>). This will block until the program completes execution. Try to avoid exec. Unlike the builtin commands, it runs the risk of getting init "stuck". |
export <name> <value> | Set the environment variable <name> equal to <value> in the global environment (which will be inherited by all processes started after this command is executed). |
ifup <interface> | Bring the network interface <interface> online. |
import <filename> | Parse an init config file, extending the current configuration. |
hostname <name> | Set the host name. |
class_start <serviceclass> | Start all services of the specified class if they are not already running. |
class_stop <serviceclass> | Stop all services of the specified class if they are currently running. |
domainname <name> | Set the domain name. |
insmod <path> | Install the module at <path>. |
mkdir <path> | Make a directory at <path>. |
mount <type> <device> <dir> [ <mountoption> ]* | Attempt to mount the named device at the directory <dir> <device>. This may be of the form mtd@name to specify a mtd block device by name. |
setkey | - currenlty undefined - |
setprop <name> <value> | Set system property <name> to <value>. |
setrlimit <resource> <cur> <max> | Set the rlimit for a resource. |
start <service> | Start a service running if it is not already running. |
stop <service> | Stop a service from running if it is currently running. |
symlink <target> <path> | Create a symbolic link at <path> with the value <target>. |
write <path> <string> [ <string> ]* | Open the file at <path> and write one or more strings to it with write(2). |
Properties
what it's doing:
| Property | Description |
|---|---|
init.action |
Equal to the name of the action currently being executed or "" if none. |
init.command |
Equal to the command being executed or "" if none. |
init.svc.<name> |
State of a named service ("stopped", "running", or "restarting"). |
在init.rc中使用属性的范例如下：
|
setprop ro.FOREGROUND_APP_MEM 1536 setprop ro.VISIBLE_APP_MEM 2048 on property:ro.kernel.qemu=1 start adbd |
setprop用于设置属性，on property可以用于判断属性，这里的属性在整个Android系统运行中都是一致的。
init脚本中的关键字可以参考：system/core/init/keywords.h
exam init.rc
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on init
sysclktz 0
loglevel 3
# setup the global environment
export PATH /sbin:/system/sbin:/system/bin:/system/xbin:/system/busybox/bin:/system/busybox/sbin:/system/busybox/usr/bin:/system/busybox/usr/sbin
export LD_LIBRARY_PATH /system/lib
export ANDROID_BOOTLOGO 1
export ANDROID_ROOT /system
export ANDROID_ASSETS /system/app
export ANDROID_DATA /data
export EXTERNAL_STORAGE /sdcard
export BOOTCLASSPATH /system/framework/core.jar:/system/framework/ext.jar:/system/framework/framework.jar:/system/framework/android.policy.jar:/system/framework/services.jar
# Backward compatibility
symlink /system/etc /etc
symlink /sys/kernel/debug /d
# create mountpoints and mount tmpfs on sqlite_stmt_journals
mkdir /sdcard 0000 system system
mkdir /system
mkdir /data 0771 system system
mkdir /cache 0770 system cache
mkdir /config 0500 root root
mkdir /sqlite_stmt_journals 01777 root root
mount tmpfs tmpfs /sqlite_stmt_journals size=4m
#{{ added by FriendlyARM
mkdir /udisk 0000 system system
mkdir /var 0000 system system
mount tmpfs tmpfs /var size=2m
mkdir /var/lock
mkdir /var/run
mkdir /var/log
mount usbfs none /proc/bus/usb -o devmode=0666
chmod 0666 /dev/backlight-1wire
#}}
## mount rootfs rootfs / ro remount
write /proc/sys/kernel/panic_on_oops 1
write /proc/sys/kernel/hung_task_timeout_secs 0
write /proc/cpu/alignment 4
write /proc/sys/kernel/sched_latency_ns 10000000
write /proc/sys/kernel/sched_wakeup_granularity_ns 2000000
write /proc/sys/kernel/sched_compat_yield 1
write /proc/sys/kernel/sched_child_runs_first 0
# Create cgroup mount points for process groups
mkdir /dev/cpuctl
mount cgroup none /dev/cpuctl cpu
chown system system /dev/cpuctl
chown system system /dev/cpuctl/tasks
chmod 0777 /dev/cpuctl/tasks
write /dev/cpuctl/cpu.shares 1024
mkdir /dev/cpuctl/fg_boost
chown system system /dev/cpuctl/fg_boost/tasks
chmod 0777 /dev/cpuctl/fg_boost/tasks
write /dev/cpuctl/fg_boost/cpu.shares 1024
mkdir /dev/cpuctl/bg_non_interactive
chown system system /dev/cpuctl/bg_non_interactive/tasks
chmod 0777 /dev/cpuctl/bg_non_interactive/tasks
# 5.0 %
write /dev/cpuctl/bg_non_interactive/cpu.shares 52
# mount mtd partitions
# Mount /system rw first to give the filesystem a chance to save a checkpoint
## mount yaffs2 mtd@system /system
## mount yaffs2 mtd@system /system ro remount
# We chown/chmod /data again so because mount is run as root + defaults
## mount yaffs2 mtd@userdata /data nosuid nodev
chown system system /data
chmod 0771 /data
# Create dump dir and collect dumps.
# Do this before we mount cache so eventually we can use cache for
# storing dumps on platforms which do not have a dedicated dump partition.
mkdir /data/dontpanic
chown root log /data/dontpanic
chmod 0750 /data/dontpanic
# Collect apanic data, free resources and re-arm trigger
copy /proc/apanic_console /data/dontpanic/apanic_console
chown root log /data/dontpanic/apanic_console
chmod 0640 /data/dontpanic/apanic_console
copy /proc/apanic_threads /data/dontpanic/apanic_threads
chown root log /data/dontpanic/apanic_threads
chmod 0640 /data/dontpanic/apanic_threads
write /proc/apanic_console 1
# Collect ramconsole data
copy /proc/last_kmsg /data/dontpanic/last_kmsg
chown root log /data/dontpanic/last_kmsg
chmod 0640 /data/dontpanic/last_kmsg
# Same reason as /data above
## mount yaffs2 mtd@cache /cache nosuid nodev
chown system cache /cache
chmod 0770 /cache
# This may have been created by the recovery system with odd permissions
chown system system /cache/recovery
chmod 0770 /cache/recovery
#change permissions on vmallocinfo so we can grab it from bugreports
chown root log /proc/vmallocinfo
chmod 0440 /proc/vmallocinfo
# create basic filesystem structure
mkdir /data/misc 01777 system misc
mkdir /data/misc/bluetoothd 0777 bluetooth bluetooth
mkdir /data/misc/keystore 0700 keystore keystore
mkdir /data/misc/vpn 0770 system system
mkdir /data/misc/vpn/profiles 0770 system system
mkdir /data/misc/wifi 0777 wifi wifi
mkdir /data/misc/wifi/sockets 0777 system wifi
chmod 0777 /data/misc/wifi
chmod 0777 /data/misc/wifi/wpa_supplicant.conf
# give system access to wpa_supplicant.conf for backup and restore
chmod 0777 /system/etc/wifi/wpa_supplicant.conf
mkdir /data/misc/dhcp 0770 dhcp dhcp
chown dhcp dhcp /data/misc/dhcp
mkdir /data/local 0771 shell shell
mkdir /data/local/tmp 0771 shell shell
mkdir /data/data 0771 system system
mkdir /data/app-private 0771 system system
mkdir /data/app 0771 system system
mkdir /data/property 0700 root root
# create dalvik-cache and double-check the perms
mkdir /data/dalvik-cache 0771 system system
chown system system /data/dalvik-cache
chmod 0771 /data/dalvik-cache
# create the lost+found directories, so as to enforce our permissions
mkdir /data/lost+found 0770
mkdir /cache/lost+found 0770
# double check the perms, in case lost+found already exists, and set owner
chown root root /data/lost+found
chmod 0770 /data/lost+found
chown root root /cache/lost+found
chmod 0770 /cache/lost+found
#===================================================================
#
# debug fs enable for wifi & bluetooth
#
#===================================================================
mount debugfs none /sys/kernel/debug
on boot
# basic network init
ifup lo
ifup eth0
ifup eth1
hostname localhost
domainname localdomain
# set RLIMIT_NICE to allow priorities from 19 to -20
setrlimit 13 40 40
# Define the oom_adj values for the classes of processes that can be
# killed by the kernel. These are used in ActivityManagerService.
setprop ro.FOREGROUND_APP_ADJ 0
setprop ro.VISIBLE_APP_ADJ 1
setprop ro.SECONDARY_SERVER_ADJ 2
setprop ro.BACKUP_APP_ADJ 2
setprop ro.HOME_APP_ADJ 4
setprop ro.HIDDEN_APP_MIN_ADJ 7
setprop ro.CONTENT_PROVIDER_ADJ 14
setprop ro.EMPTY_APP_ADJ 15
# Define the memory thresholds at which the above process classes will
# be killed. These numbers are in pages (4k).
setprop ro.FOREGROUND_APP_MEM 1536
setprop ro.VISIBLE_APP_MEM 2048
setprop ro.SECONDARY_SERVER_MEM 4096
setprop ro.BACKUP_APP_MEM 4096
setprop ro.HOME_APP_MEM 4096
setprop ro.HIDDEN_APP_MEM 5120
setprop ro.CONTENT_PROVIDER_MEM 5632
setprop ro.EMPTY_APP_MEM 6144
#Wifi
# insmod /system/lib/libwifi/lib80211.ko
# insmod /system/lib/libwifi/lib80211_crypt_ccmp.ko
# insmod /system/lib/libwifi/lib80211_crypt_tkip.ko
# insmod /system/lib/libwifi/lib80211_crypt_wep.ko
# insmod /system/lib/modules/2.6.27/kernel/net/bluetooth/bluetooth.ko
# insmod /system/lib/modules/2.6.27/kernel/drivers/bluetooth/hci_uart.ko
# insmod /system/lib/modules/2.6.27/kernel/net/bluetooth/l2cap.ko
# insmod /system/lib/modules/2.6.27/kernel/net/bluetooth/rfcomm/rfcomm.ko
setprop wifi.interface eth1
setprop wlan.interface eth1
setprop wlan.driver.status ok
setprop wlan.modpath /system/lib/libwifi/
setprop wlan.mod1 libertas.ko
setprop wlan.mod2 libertas_sdio.ko
# Write value must be consistent with the above properties.
# Note that the driver only supports 6 slots, so we have HOME_APP at the
# same memory level as services.
write /sys/module/lowmemorykiller/parameters/adj 0,1,2,7,14,15
write /proc/sys/vm/overcommit_memory 1
write /proc/sys/vm/min_free_order_shift 4
write /sys/module/lowmemorykiller/parameters/minfree 1536,2048,4096,5120,5632,6144
# Set init its forked children's oom_adj.
write /proc/1/oom_adj -16
# Tweak background writeout
write /proc/sys/vm/dirty_expire_centisecs 200
write /proc/sys/vm/dirty_background_ratio 5
# Permissions for System Server and daemons.
chown radio system /sys/android_power/state
chown radio system /sys/android_power/request_state
chown radio system /sys/android_power/acquire_full_wake_lock
chown radio system /sys/android_power/acquire_partial_wake_lock
chown radio system /sys/android_power/release_wake_lock
chown radio system /sys/power/state
chown radio system /sys/power/wake_lock
chown radio system /sys/power/wake_unlock
chmod 0660 /sys/power/state
chmod 0660 /sys/power/wake_lock
chmod 0660 /sys/power/wake_unlock
chown system system /sys/class/timed_output/vibrator/enable
chown system system /sys/class/leds/keyboard-backlight/brightness
# chown system system /sys/class/leds/lcd-backlight/brightness
chown system system /sys/class/backlight/pwm-backlight/brightness
chown system system /sys/class/leds/button-backlight/brightness
chown system system /sys/class/leds/jogball-backlight/brightness
chown system system /sys/class/leds/red/brightness
chown system system /sys/class/leds/green/brightness
chown system system /sys/class/leds/blue/brightness
chown system system /sys/class/leds/red/device/grpfreq
chown system system /sys/class/leds/red/device/grppwm
chown system system /sys/class/leds/red/device/blink
chown system system /sys/class/leds/red/brightness
chown system system /sys/class/leds/green/brightness
chown system system /sys/class/leds/blue/brightness
chown system system /sys/class/leds/red/device/grpfreq
chown system system /sys/class/leds/red/device/grppwm
chown system system /sys/class/leds/red/device/blink
chown system system /sys/class/timed_output/vibrator/enable
chown system system /sys/module/sco/parameters/disable_esco
chown system system /sys/kernel/ipv4/tcp_wmem_min
chown system system /sys/kernel/ipv4/tcp_wmem_def
chown system system /sys/kernel/ipv4/tcp_wmem_max
chown system system /sys/kernel/ipv4/tcp_rmem_min
chown system system /sys/kernel/ipv4/tcp_rmem_def
chown system system /sys/kernel/ipv4/tcp_rmem_max
chown root radio /proc/cmdline
#bluetooth power up/down interface
# chown bluetooth bluetooth /sys/class/rfkill/rfkill0/type
# chown bluetooth bluetooth /sys/class/rfkill/rfkill0/state
# chmod 0660 /sys/class/rfkill/rfkill0/state
# chown bluetooth bluetooth /dev/s3c2410_serial1
chmod 0666 /dev/s3c2410_serial1
chmod 0666 /dev/s3c2410_serial2
chmod 0666 /dev/s3c2410_serial3
chmod 0666 /dev/video0
chmod 0666 /dev/s3c-jpg
# Define TCP buffer sizes for various networks
# ReadMin, ReadInitial, ReadMax, WriteMin, WriteInitial, WriteMax,
setprop net.tcp.buffersize.default 4096,87380,110208,4096,16384,110208
setprop net.tcp.buffersize.wifi 4095,87380,110208,4096,16384,110208
setprop net.tcp.buffersize.umts 4094,87380,110208,4096,16384,110208
setprop net.tcp.buffersize.edge 4093,26280,35040,4096,16384,35040
setprop net.tcp.buffersize.gprs 4092,8760,11680,4096,8760,11680
setprop net.dns1 8.8.8.8
setprop net.dns2 8.8.4.4
class_start default
setprop alsa.mixer.playback.master Front
setprop alsa.mixer.capture.master Capture
setprop alsa.mixer.playback.earpiece Master
setprop alsa.mixer.capture.earpiece Capture
setprop alsa.mixer.playback.headset Master
setprop alsa.mixer.playback.speaker Master
## Daemon processes to be run by init.
##
service console /system/bin/sh
#service console /system/busybox/bin/ash
console
# adbd is controlled by the persist.service.adb.enable system property
service adbd /sbin/adbd
disabled
# adbd on at boot in emulator
on property:ro.kernel.qemu=1
start adbd
on property:persist.service.adb.enable=1
start adbd
on property:persist.service.adb.enable=0
stop adbd
service servicemanager /system/bin/servicemanager
user system
critical
onrestart restart zygote
onrestart restart media
service vold /system/bin/vold
socket vold stream 0660 root mount
service tsd /sbin/tsd
service nexus /system/bin/nexus
socket nexus stream 0660 root system
disabled
#service mountd /system/bin/mountd
# socket mountd stream 0660 root mount
service debuggerd /system/bin/debuggerd
service udiskd /system/bin/udiskd
socket udiskd stream 666 root mount
service fanetworkservice /system/bin/fa-network-service
socket fa-network-service stream 666 radio radio
user root
group radio cache inet misc audio
#user radio
#group radio cache inet misc audio
service ril-daemon /system/bin/rild -l /system/lib/libreference-ril.so -- -d /dev/pts/0
socket rild stream 660 root radio
socket rild-debug stream 660 radio system
user root
group radio cache inet misc audio
service zygote /system/bin/app_process -Xzygote /system/bin --zygote --start-system-server
socket zygote stream 666
onrestart write /sys/android_power/request_state wake
onrestart write /sys/power/state on
onrestart restart media
service media /system/bin/mediaserver
user media
group system audio camera graphics inet net_bt net_bt_admin
##service bootsound /system/bin/playmp3
## user media
## group audio
## oneshot
service bootanim /system/bin/bootanimation
user graphics
group graphics
disabled
oneshot
service dbus /system/bin/dbus-daemon --system --nofork
socket dbus stream 660 bluetooth bluetooth
user bluetooth
group bluetooth net_bt_admin
service wpa_supplicant /system/bin/logwrapper /system/bin/wpa_supplicant -Dwext -ieth1 -c /system/etc/wifi/wpa_supplicant.conf -dd
group system wifi inet keystore
disabled
oneshot
service dhcpcd /system/bin/logwrapper /system/bin/dhcpcd -d eth1
disabled
oneshot
group system dhcp
on property:init.svc.wpa_supplicant=stopped
stop dhcpcd
service bluetoothd /system/bin/logwrapper /system/bin/bluetoothd -d -n
socket bluetooth stream 660 bluetooth bluetooth
socket dbus_bluetooth stream 660 bluetooth bluetooth
# init.rc does not yet support applying capabilities, so run as root and
# let bluetoothd drop uid to bluetooth with the right linux capabilities
group bluetooth net_bt_admin misc
disabled
# baudrate change 115200 to 1152000(Bluetooth)
service changebaudrate /system/bin/logwrapper /system/xbin/bccmd_115200 -t bcsp -d /dev/s3c2410_serial1 psset -r 0x1be 0x126e
user bluetooth
group bluetooth net_bt_admin
disabled
oneshot
#service hciattach /system/bin/logwrapper /system/bin/hciattach -n -s 1152000 /dev/s3c2410_serial1 bcsp 1152000
service hciattach /system/bin/logwrapper /system/bin/hciattach -n -s 115200 /dev/s3c2410_serial1 bcsp 115200
user bluetooth
group bluetooth net_bt_admin misc
disabled
service hfag /system/bin/sdptool add --channel=10 HFAG
user bluetooth
group bluetooth net_bt_admin
disabled
oneshot
service hsag /system/bin/sdptool add --channel=11 HSAG
user bluetooth
group bluetooth net_bt_admin
disabled
oneshot
service opush /system/bin/sdptool add --channel=12 OPUSH
user bluetooth
group bluetooth net_bt_admin
disabled
oneshot
service pbap /system/bin/sdptool add --channel=19 PBAP
user bluetooth
group bluetooth net_bt_admin
disabled
oneshot
service installd /system/bin/installd
socket installd stream 600 system system
##service flash_recovery /system/etc/install-recovery.sh
## oneshot
service racoon /system/bin/racoon
socket racoon stream 600 system system
# racoon will setuid to vpn after getting necessary resources.
group net_admin
disabled
oneshot
service mtpd /system/bin/mtpd
socket mtpd stream 600 system system
user vpn
group vpn net_admin net_raw
disabled
oneshot
service keystore /system/bin/keystore /data/misc/keystore
user keystore
group keystore
socket keystore stream 666
service dumpstate /system/bin/dumpstate -s
socket dumpstate stream 0660 shell log
disabled
oneshot
