Merge "init: Update readme.txt to reflect recent changes to init"

These directories are intended for all Actions and Services used after

file system mounting.

One may specify paths in the mount_all command line to have it import

.rc files at the specified paths instead of the default ones listed above.

This is primarily for supporting factory mode and other non-standard boot

modes.  The three default paths should be used for the normal boot process.

The intention of these directories is as follows

   1) /system/etc/init/ is for core system items such as

      SurfaceFlinger and MediaService.

      SurfaceFlinger, MediaService, and logcatd.

   2) /vendor/etc/init/ is for SoC vendor items such as actions or

      daemons needed for core SoC functionality.

   3) /odm/etc/init/ is for device manufacturer items such as

      actions or daemons needed for motion sensor or other peripheral

      functionality.

One may specify paths in the mount_all command line to have it import

.rc files at the specified paths instead of the default ones described above.

All services whose binaries reside on the system, vendor, or odm

partitions should have their service entries placed into a

corresponding init .rc file, located in the /etc/init/

directory of the partition where they reside.  There is a build

system macro, LOCAL_INIT_RC, that handles this for developers.  Each

init .rc file should additionally contain any actions associated with

its service.

An example is the logcatd.rc and Android.mk files located in the

system/core/logcat directory.  The LOCAL_INIT_RC macro in the

Android.mk file places logcatd.rc in /system/etc/init/ during the

build process.  Init loads logcatd.rc during the mount_all command and

allows the service to be run and the action to be queued when

appropriate.

This break up of init .rc files according to their daemon is preferred

to the previously used monolithic init .rc files.  This approach

ensures that the only service entries that init reads and the only

actions that init performs correspond to services whose binaries are in

fact present on the file system, which was not the case with the

monolithic init .rc files.  This additionally will aid in merge

conflict resolution when multiple services are added to the system, as

each one will go into a separate file.

Actions

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