README

Ideal Init

The point of this program is to allow people easily determine which init
system-calls must be made during their respective device's boot process in
order to more-easily port custom ROMs to their devices.

I wrote this utility because Qualcomm's init implementation is very ugly and
consists of multiple (and oftentimes useless) init*.rc files and shell scripts.

The first (and most important) part of this program is to make the necessary
changes to the kernel to print which system calls are being made, so that they
can be intercepeted and logged in the kernel's dmesg buffer. Then the user must
dump their dmesg onto their computer and and run the program called ideal_init.
This program will interpret the intercepted system calls and (hopefully)
generate output which resembles a viable (and single) init.<device>.rc.

The ideal_init program also filters out the intercepted system calls made by
the init processes against the default init.rc scripts that are used for AOSP
ROMs, (syscalls made by init.rc, init.trace.rc, etc) so that there is no
duplicate** data that may cause adverse effects.

A big part of the device's init bringup is when the init scripts set certain
device properties. Because 'setprop' is not a system call, a secondary
userspace program called 'prop_watch' had to be crafted from the Android
toolbox's program called watchprops. This change was needed to spy on whether a
script called 'setprop', and this process must be started from your device's
init.rc right when it boots (the daemon should be placed in /sbin).

Instructions:
1. Revert your device back to 100% stock (and rooted of course)

2. Make the necessary changes from 'required_patches/kernel.diff' to your
   device's stock kernel source, and add CONFIG_IDEAL_INIT=y to your defconfig

3. Now that you have made the changes to your kernel source, compile the kernel

4. Extract your device's stock boot.img. This will likely create two files; one
   which is the ramdisk, and one that is the kernel

5. Extract the ramdisk, and make the necessary changes to your ramdisk's
   init.rc file from 'required_patches/init_rc.diff'

6. Copy the prop_watch binary from the 'bin' folder to your stock ramdisk under
   /sbin/prop_watch

7. Now that you have edited your stock ramdisk's init.rc file and copied
   prop_watch to your device's stock ramdisk, remake your ramdisk from the
   extracted files

8. Remake your boot.img, this time using your kernel compiled from step 3, and
   your ramdisk with the necesssary changes from step 7

9. Flash your boot.img to your device, and reboot

10. After your device has completely booted, pull your kernel logs with
    something like: 'adb shell dmesg >> /home/user/syscalls.txt'

11. The file under /home/user/syscalls.txt has all of your kernel's dmesg logs
    as well as the logged system calls made by your init scripts, now we must
    extract JUST the logged system calls with something like:
    'strings /home/user/syscalls.txt | grep II: >> /home/user/JUST_II_DATA.txt'

12. Copy the file called 'JUST_II_DATA.txt' to the directory this file is in

13. Compile the ideal_init program with 'make'

14. Copy your device's init*.rc files to the directory called
    'device_init_files'

15. Copy any init shell scripts from /system/etc to 'device_init_files'

16. Copy any init scripts from:
    https://android.googlesource.com/platform/system/core/+/<release>/rootdir/
    where <release> corresponds to whatever version of Android your stock dump
    is

17. Plug your phone into your computer, and make sure adb works

18. Run the program ideal_init and it should print out a viable working
    init.<device>.rc which is a fantastic starting point for porting ROMs
    to your device

What CAN'T this program do/log/catch? It cannot log when variables are exported
using the 'export' by init.rc scripts, so things like:
'export EXTERNAL_STORAGE /storage/emulated/legacy' must be done manually by the
developer, and must be placed in the proper init trigger. It also cannot catch
the 'restorecon' keyword, so those must be added manually. It also cannot catch
triggers set by property changes, so things like:

on property:init.svc.wpa_supplicant=stopped
    stop dhcpcd

must be added manually. Another thing to mention is that a setprop command made
by an init script should be verified that it's in the correct section of the
init file. Due to setprop not being a system call, we must use a userspace
program to spy on whether a setprop command has been issued; so this program
may say that a certain property was set in the 'boot' part of the init
process, but in reality it was actually set by in 'early-boot' section of the
init process, but by the time the process scheduler ran the prop_watch program
to spy on whether a property was set, it may appear that the change was made in
'boot' because the kernel has higher priority than userspace programs.

To sum up what Ideal Init cannot do:
1. You must manually add exported variables becuase 'export' is not a syscall

2. You must manually add restorecons because 'restorecon' is not a syscall

3. You must manually add triggers because those are not syscalls

4. You should verify in your device's ramdisk that when a setprop is made in
   a certain section of the init script, it is properly reflected in the
   Ideal Init output that it's in the correct section