Android init language与init.rc初始化脚本
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参考: android源码目录里的system/core/init/readme.txt.
Android系统里以*.rc为扩展名为系统初始化脚本,脚本里就是使用安卓初始化语言.
语句都是一行为一条语句,没有符号分隔. 语句里的每个词用空格隔开.
如: service ueventd /sbin/ueventd
备注语句以符号”#”作为注释.
语言基本上分为4个块: Actions Commands Services 和 Options.
每个Actions和Services关键词开始的语句作为一个新的区块.
Commands和Options就是属于就近的Actions或Services块.
如:
Actions的形式:
1on <trigger>
2 <command>
3 <command>
4 <command>
Services的形式:
1service <name> <pathname> [ <argument> ]*
2 <option>
3 <option>
rc文件里实例:
1service logd /system/bin/logd
2 class core
3 socket logd stream 0666 logd logd
4 socket logdr seqpacket 0666 logd logd
5 socket logdw dgram 0222 logd logd
6 group root system
7 writepid /dev/cpuset/system-background/tasks
8
9service healthd /sbin/healthd
10 class core
11 critical
12 seclabel u:r:healthd:s0
13
14# Actions
15# on
16on property:sys.powerctl=*
17 powerctl ${sys.powerctl}
18
19on early-init
20 # Set init and its forked children's oom_adj.
21 write /proc/1/oom_score_adj -1000
22 # Set the security context of /adb_keys if present.
23 restorecon /adb_keys
24 start ueventd
每个rc文件里又可以包含其它rc文件:
1import /init.environ.rc
2import /init.usb.rc
3import /init.${ro.hardware}.rc
4import /init.usb.configfs.rc
5import /init.${ro.zygote}.rc
6import /init.trace.rc
Actions里常用的trigger有:
1on early-init
2
3
4on init
5
6
7on late-init
8
9
10on post-fs
11
12
13on boot
14
15
16on property:sys.init_log_level=* //在设置属性值时触发
17
18
19on charger
20
21
22on property:sys.powerctl=*
23
常用的Commands有:
//参考system/core/init/keywords.h
1bootchart_init
2 Start bootcharting if configured (see below).
3 This is included in the default init.rc.
4
5chmod mode> <path>
6 Change file access permissions.
7
8chown <group> <path>
9 Change file owner and group.
10
11class_start
12 Start all services of the specified class if they are
13 not already running.
14
15class_stop
16 Stop and disable all services of the specified class if they are
17 currently running.
18
19class_reset
20 Stop all services of the specified class if they are
21 currently running, without disabling them. They can be restarted
22 later using class_start.
23
24copy
25 Copies a file. Similar to write, but useful for binary/large
26 amounts of data.
27
28domainname <name>
29 Set the domain name.
30
31enable
32 Turns a disabled service into an enabled one as if the service did not
33 specify disabled.
34 If the service is supposed to be running, it will be started now.
35 Typically used when the bootloader sets a variable that indicates a specific
36 service should be started when needed. E.g.
37 on property:ro.boot.myfancyhardware=1
38 enable my_fancy_service_for_my_fancy_hardware
39
40exec [ [ <user> [ <group> ]* ] ] -- [ ]*
41 Fork and execute command with the given arguments. The command starts
42 after "--" so that an optional security context, user, and supplementary
43 groups can be provided. No other commands will be run until this one
44 finishes. can be a - to denote default.
45
46export <name> <value>
47 Set the environment variable <name> equal to <value> in the
48 global environment (which will be inherited by all processes
49 started after this command is executed)
50
51hostname <name>
52 Set the host name.
53
54ifup <interface>
55 Bring the network interface <interface> online.
56
57import
58 Parse an init config file, extending the current configuration.
59
60insmod <path>
61 Install the module at <path>
62
63load_all_props
64 Loads properties from /system, /vendor, et cetera.
65 This is included in the default init.rc.
66
67load_persist_props
68 Loads persistent properties when /data has been decrypted.
69 This is included in the default init.rc.
70
71loglevel <level>
72 Sets the kernel log level to level. Properties are expanded within <level>.
73
74mkdir <path> [mode] [owner] [group]
75 Create a directory at <path>, optionally with the given mode, owner, and
76 group. If not provided, the directory is created with permissions 755 and
77 owned by the root user and root group. If provided, the mode, owner and group
78 will be updated if the directory exists already.
79
80mount_all
81 Calls fs_mgr_mount_all on the given fs_mgr-format fstab.
82
83mount <type> [ ]* []
84 Attempt to mount the named device at the directory
85 may be of the form mtd@name to specify a mtd block
86 device by name.
87 s include "ro", "rw", "remount", "noatime", ...
88 include "barrier=1", "noauto_da_alloc", "discard", ... as
89 a comma separated string, eg: barrier=1,noauto_da_alloc
90
91powerctl
92 Internal implementation detail used to respond to changes to the
93 "sys.powerctl" system property, used to implement rebooting.
94
95restart
96 Like stop, but doesn't disable the service.
97
98restorecon [ ]*
99 Restore the file named by to the security context specified
100 in the file_contexts configuration.
101 Not required for directories created by the init.rc as these are
102 automatically labeled correctly by init.
103
104restorecon_recursive [ ]*
105 Recursively restore the directory tree named by to the
106 security contexts specified in the file_contexts configuration.
107
108rm
109 Calls unlink(2) on the given path. You might want to
110 use "exec -- rm ..." instead (provided the system partition is
111 already mounted).
112
113rmdir
114 Calls rmdir(2) on the given path.
115
116setprop
117 Set system property to . Properties are expanded
118 within .
119
120setrlimit
121 Set the rlimit for a resource.
122
123start
124 Start a service running if it is not already running.
125
126stop
127 Stop a service from running if it is currently running.
128
129swapon_all
130 Calls fs_mgr_swapon_all on the given fstab file.
131
132symlink
133 Create a symbolic link at with the value
134
135sysclktz
136 Set the system clock base (0 if system clock ticks in GMT)
137
138trigger
139 Trigger an event. Used to queue an action from another
140 action.
141
142verity_load_state
143 Internal implementation detail used to load dm-verity state.
144
145verity_update_state
146 Internal implementation detail used to update dm-verity state and
147 set the partition..verified properties used by adb remount
148 because fs_mgr can' t set them directly itself.
149
150wait <path> [ <timeout> ]
151 Poll for the existence of the given file and return when found,
152 or the timeout has been reached. If timeout is not specified it
153 currently defaults to five seconds.
154
155write <path> <content>
156 Open the file at <path> and write a string to it with write(2).
157 If the file does not exist, it will be created. If it does exist,
158 it will be truncated. Properties are expanded within <content>.
Services里常用的options有:
1critical
2 This is a device-critical service. If it exits more than four times in
3 four minutes, the device will reboot into recovery mode.
4
5disabled
6 This service will not automatically start with its class.
7 It must be explicitly started by name.
8
9setenv
10 Set the environment variable to in the launched process.
11
12socket [ [ <group> [ ] ] ]
13 Create a unix domain socket named /dev/socket/ and pass
14 its fd to the launched process. must be "dgram", "stream" or "seqpacket".
15 User and group default to 0.
16 'seclabel' is the SELinux security context for the socket.
17 It defaults to the service security context, as specified by seclabel or
18 computed based on the service executable file security context.
19
20user
21 Change to username before exec'ing this service.
22 Currently defaults to root. (??? probably should default to nobody)
23 Currently, if your process requires linux capabilities then you cannot use
24 this command. You must instead request the capabilities in-process while
25 still root, and then drop to your desired uid.
26
27group [ ]*
28 Change to groupname before exec'ing this service. Additional
29 groupnames beyond the (required) first one are used to set the
30 supplemental groups of the process (via setgroups()).
31 Currently defaults to root. (??? probably should default to nobody)
32
33seclabel
34 Change to 'seclabel' before exec'ing this service.
35 Primarily for use by services run from the rootfs, e.g. ueventd, adbd.
36 Services on the system partition can instead use policy-defined transitions
37 based on their file security context.
38 If not specified and no transition is defined in policy, defaults to the init context.
39
40oneshot
41 Do not restart the service when it exits.
42
43class
44 Specify a class name for the service. All services in a
45 named class may be started or stopped together. A service
46 is in the class "default" if one is not specified via the
47 class option.
48
49onrestart
50 Execute a Command (see below) when service restarts.
51
52writepid
53 Write the child's pid to the given files when it forks. Meant for
54 cgroup/cpuset usage.
实现直接使用root用户进入终端, 修改android/out/target/product/tulip-p1/root/init.rc :
1service console /system/bin/sh
2 class core
3 console
4 disabled
5 # user shell
6 # group shell log
7 # seclabel u:r:shell:s0
//备注使用shell用户进入终端. 会默认使用root用户操作
实现系统进入后执行自定义的脚本 :
修改android/out/target/product/tulip-p1/root/init.rc , 增加内容:
1service start_mytest /system/bin/mytest.sh
2 oneshot
3 on property:sys.boot_completed=1
4 start start_mytest
在android/out/target/product/tulip-p1/system/bin目录下,增加mytest.sh, 内容:
1#!/system/bin/sh
2
3echo "mytest ...!" > /dev/ttyS0
4echo "mytest ...!" > /dev/ttyS0
5echo "mytest ...!" > /dev/ttyS0
6echo "mytest ...!" > /dev/ttyS0
7echo "mytest ...!" > /dev/ttyS0
8echo "mytest ...!" > /dev/ttyS0
9echo "mytest ...!" > /dev/ttyS0
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