Adding init script to reboot android marshmallow tablet when it's booted with usb charging

Question

I have tried to make script to reboot tablet from charging mode to normal if it's started by pluging usb charger. Android init language is quite straightforward but actually how it's then parced is quite mystery to me.

so i have my_script.sh implemented on root. Added to the system file my_script.sh initrd/my_script.sh 0750 and repacked boot.img. Verified that everything is it place and access rights should be correct.

#!/system/bin/sh
/system/bin/reboot -c reboot now

Then i have in init.rc

service rebootit /system/bin/sh /my_script.sh
    class main
    user root
    oneshot

then i have put following under "on charger" at init.rc

start rebootit

Any idea how this could be achieved?

Edit 1. Tried following.

service rebootit /system/bin/reboot -c reboot now
    class main
    user root
    oneshot

This was the outcome.

 [4.648753] init: cannot execve('/system/bin/reboot'): Permission denied
 [4.649167] type=1400 audit(85946.779:4): avc: denied { execute_no_trans } for pid=331 comm="init" path="/system/bin/reboot" dev="mmcblk0p21" ino=730 scontext=u:r:init:s0 tcontext=u:object_r:system_file:s0 tclass=file permissive=0

Edit 2.

Ok. Some progress. echo b > /proc/sysrq-trigger seems to reboot but now i need to found some variable which i can use to separate script running when booting to normal mode. I have tried to use this kind of script which i found from another init file. just modifid it suit my needs but still no luck.

#!/system/bin/sh
bootmode=`getprop ro.bootmode`
if [ "$bootmode" = "charger" ]; then # Reboot the tablet
echo b > /proc/sysrq-trigger
fi

Edit 3. The Solution

Now i finally got it.

On init.rc i have added following:

#Check if chargermode and start rebootit service.
on property:ro.bootmode=charger
    start rebootit   

and after it added following:

#rebootit service which command reboot
service rebootit /su/bin/su /system/bin/reboot -c reboot now
    user root
    oneshot

You need to have SU installed to work.