diff options
Diffstat (limited to 'init/readme.txt')
| -rw-r--r-- | init/readme.txt | 293 |
1 files changed, 0 insertions, 293 deletions
diff --git a/init/readme.txt b/init/readme.txt deleted file mode 100644 index 665090bad..000000000 --- a/init/readme.txt +++ /dev/null @@ -1,293 +0,0 @@ - -Android Init Language ---------------------- - -The Android Init Language consists of four broad classes of statements, -which are Actions, Commands, Services, and Options. - -All of these are line-oriented, consisting of tokens separated by -whitespace. The c-style backslash escapes may be used to insert -whitespace into a token. Double quotes may also be used to prevent -whitespace from breaking text into multiple tokens. The backslash, -when it is the last character on a line, may be used for line-folding. - -Lines which start with a # (leading whitespace allowed) are comments. - -Actions and Services implicitly declare a new section. All commands -or options belong to the section most recently declared. Commands -or options before the first section are ignored. - -Actions and Services have unique names. If a second Action or Service -is declared with the same name as an existing one, it is ignored as -an error. (??? should we override instead) - - -Actions -------- -Actions are named sequences of commands. Actions have a trigger which -is used to determine when the action should occur. When an event -occurs which matches an action's trigger, that action is added to -the tail of a to-be-executed queue (unless it is already on the -queue). - -Each action in the queue is dequeued in sequence and each command in -that action is executed in sequence. Init handles other activities -(device creation/destruction, property setting, process restarting) -"between" the execution of the commands in activities. - -Actions take the form of: - -on <trigger> - <command> - <command> - <command> - - -Services --------- -Services are programs which init launches and (optionally) restarts -when they exit. Services take the form of: - -service <name> <pathname> [ <argument> ]* - <option> - <option> - ... - - -Options -------- -Options are modifiers to services. They affect how and when init -runs the service. - -critical - This is a device-critical service. If it exits more than four times in - four minutes, the device will reboot into recovery mode. - -disabled - This service will not automatically start with its class. - It must be explicitly started by name. - -setenv <name> <value> - Set the environment variable <name> to <value> in the launched process. - -socket <name> <type> <perm> [ <user> [ <group> ] ] - Create a unix domain socket named /dev/socket/<name> and pass - its fd to the launched process. <type> must be "dgram" or "stream". - User and group default to 0. - -user <username> - Change to username before exec'ing this service. - Currently defaults to root. (??? probably should default to nobody) - Currently, if your process requires linux capabilities then you cannot use - this command. You must instead request the capabilities in-process while - still root, and then drop to your desired uid. - -group <groupname> [ <groupname> ]* - Change to groupname before exec'ing this service. Additional - groupnames beyond the (required) first one are used to set the - supplemental groups of the process (via setgroups()). - Currently defaults to root. (??? probably should default to nobody) - -oneshot - Do not restart the service when it exits. - -class <name> - Specify a class name for the service. All services in a - named class may be started or stopped together. A service - is in the class "default" if one is not specified via the - class option. - -onrestart - Execute a Command (see below) when service restarts. - -Triggers --------- - Triggers are strings which can be used to match certain kinds - of events and used to cause an action to occur. - -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. - - -Commands --------- - -exec <path> [ <argument> ]* - Fork and execute a program (<path>). This will block until - the program completes execution. It is best to avoid exec - as unlike the builtin commands, it runs the risk of getting - init "stuck". (??? maybe there should be a timeout?) - -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. - -chmod <octal-mode> <path> - Change file access permissions. - -chown <owner> <group> <path> - Change file owner and group. - -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> [mode] [owner] [group] - Create a directory at <path>, optionally with the given mode, owner, and - group. If not provided, the directory is created with permissions 755 and - owned by the root user and root group. - -mount <type> <device> <dir> [ <mountoption> ]* - Attempt to mount the named device at the directory <dir> - <device> may be of the form mtd@name to specify a mtd block - device by name. - <mountoption>s include "ro", "rw", "remount", "noatime", ... - -setkey - TBD - -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> - -sysclktz <mins_west_of_gmt> - Set the system clock base (0 if system clock ticks in GMT) - -trigger <event> - Trigger an event. Used to queue an action from another - action. - -write <path> <string> [ <string> ]* - Open the file at <path> and write one or more strings - to it with write(2) - - -Properties ----------- -Init updates some system properties to provide some insight into -what it's doing: - -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", "restarting") - - -Example init.conf ------------------ - -# not complete -- just providing some examples of usage -# -on boot - export PATH /sbin:/system/sbin:/system/bin - export LD_LIBRARY_PATH /system/lib - - mkdir /dev - mkdir /proc - mkdir /sys - - mount tmpfs tmpfs /dev - mkdir /dev/pts - mkdir /dev/socket - mount devpts devpts /dev/pts - mount proc proc /proc - mount sysfs sysfs /sys - - write /proc/cpu/alignment 4 - - ifup lo - - hostname localhost - domainname localhost - - mount yaffs2 mtd@system /system - mount yaffs2 mtd@userdata /data - - import /system/etc/init.conf - - class_start default - -service adbd /sbin/adbd - user adb - group adb - -service usbd /system/bin/usbd -r - user usbd - group usbd - socket usbd 666 - -service zygote /system/bin/app_process -Xzygote /system/bin --zygote - socket zygote 666 - -service runtime /system/bin/runtime - user system - group system - -on device-added-/dev/compass - start akmd - -on device-removed-/dev/compass - stop akmd - -service akmd /sbin/akmd - disabled - user akmd - group akmd - -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 |