Magisk/scripts/boot_patch.sh
2019-03-13 16:51:22 -04:00

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#!/system/bin/sh
##########################################################################################
#
# Magisk Boot Image Patcher
# by topjohnwu
#
# Usage: boot_patch.sh <bootimage>
#
# The following flags can be set in environment variables:
# KEEPVERITY, KEEPFORCEENCRYPT
#
# This script should be placed in a directory with the following files:
#
# File name Type Description
#
# boot_patch.sh script A script to patch boot. Expect path to boot image as parameter.
# (this file) The script will use binaries and files in its same directory
# to complete the patching process
# util_functions.sh script A script which hosts all functions requires for this script
# to work properly
# magiskinit binary The binary to replace /init, which has the magisk binary embedded
# magiskboot binary A tool to unpack boot image, decompress ramdisk, extract ramdisk,
# and patch the ramdisk for Magisk support
# chromeos folder This folder should store all the utilities and keys to sign
# (optional) a chromeos device. Used for Pixel C
#
# If the script is not running as root, then the input boot image should be a stock image
# or have a backup included in ramdisk internally, since we cannot access the stock boot
# image placed under /data we've created when previously installed
#
##########################################################################################
##########################################################################################
# Functions
##########################################################################################
# Pure bash dirname implementation
getdir() {
case "$1" in
*/*) dir=${1%/*}; [ -z $dir ] && echo "/" || echo $dir ;;
*) echo "." ;;
esac
}
##########################################################################################
# Initialization
##########################################################################################
if [ -z $SOURCEDMODE ]; then
# Switch to the location of the script file
cd "`getdir "${BASH_SOURCE:-$0}"`"
# Load utility functions
. ./util_functions.sh
fi
BOOTIMAGE="$1"
[ -e "$BOOTIMAGE" ] || abort "$BOOTIMAGE does not exist!"
# Flags
[ -z $KEEPVERITY ] && KEEPVERITY=false
[ -z $KEEPFORCEENCRYPT ] && KEEPFORCEENCRYPT=false
chmod -R 755 .
# Extract magisk if doesn't exist
[ -e magisk ] || ./magiskinit -x magisk magisk
##########################################################################################
# Unpack
##########################################################################################
CHROMEOS=false
ui_print "- Unpacking boot image"
./magiskboot unpack "$BOOTIMAGE"
case $? in
1 )
abort "! Unsupported/Unknown image format"
;;
2 )
ui_print "- ChromeOS boot image detected"
CHROMEOS=true
;;
esac
##########################################################################################
# Ramdisk restores
##########################################################################################
# Test patch status and do restore
ui_print "- Checking ramdisk status"
if [ -e ramdisk.cpio ]; then
./magiskboot cpio ramdisk.cpio test
STATUS=$?
else
# Stock A only system-as-root
STATUS=0
fi
case $((STATUS & 3)) in
0 ) # Stock boot
ui_print "- Stock boot image detected"
ui_print "- Backing up stock boot image"
SHA1=`./magiskboot --sha1 "$BOOTIMAGE" 2>/dev/null`
STOCKDUMP=stock_boot_${SHA1}.img.gz
./magiskboot compress "$BOOTIMAGE" $STOCKDUMP
cp -af ramdisk.cpio ramdisk.cpio.orig 2>/dev/null
;;
1 ) # Magisk patched
ui_print "- Magisk patched boot image detected"
# Find SHA1 of stock boot image
[ -z $SHA1 ] && SHA1=`./magiskboot --cpio ramdisk.cpio sha1 2>/dev/null`
./magiskboot cpio ramdisk.cpio restore
if ./magiskboot cpio ramdisk.cpio "exists init.rc"; then
# Normal boot image
cp -af ramdisk.cpio ramdisk.cpio.orig
else
# A only system-as-root
rm -f ramdisk.cpio
fi
;;
2 ) # Unsupported
ui_print "! Boot image patched by unsupported programs"
abort "! Please restore back to stock boot image"
;;
esac
##########################################################################################
# Ramdisk patches
##########################################################################################
ui_print "- Patching ramdisk"
echo "KEEPVERITY=$KEEPVERITY" > config
echo "KEEPFORCEENCRYPT=$KEEPFORCEENCRYPT" >> config
[ ! -z $SHA1 ] && echo "SHA1=$SHA1" >> config
./magiskboot cpio ramdisk.cpio \
"add 750 init magiskinit" \
"patch $KEEPVERITY $KEEPFORCEENCRYPT" \
"backup ramdisk.cpio.orig" \
"mkdir 000 .backup" \
"add 000 .backup/.magisk config"
if [ $((STATUS & 4)) -ne 0 ]; then
ui_print "- Compressing ramdisk"
./magiskboot --cpio ramdisk.cpio compress
fi
rm -f ramdisk.cpio.orig config
##########################################################################################
# Binary patches
##########################################################################################
if ! $KEEPVERITY; then
[ -f dtb ] && ./magiskboot dtb-patch dtb && ui_print "- Removing dm(avb)-verity in dtb"
[ -f kernel_dtb ] && ./magiskboot dtb-patch kernel_dtb && ui_print "- Removing dm(avb)-verity in dtb"
[ -f extra ] && ./magiskboot dtb-patch extra && ui_print "- Removing dm(avb)-verity in extra-dtb"
fi
if [ -f kernel ]; then
# Remove Samsung RKP
./magiskboot hexpatch kernel \
49010054011440B93FA00F71E9000054010840B93FA00F7189000054001840B91FA00F7188010054 \
A1020054011440B93FA00F7140020054010840B93FA00F71E0010054001840B91FA00F7181010054
# Remove Samsung defex
# Before: [mov w2, #-221] (-__NR_execve)
# After: [mov w2, #-32768]
./magiskboot hexpatch kernel 821B8012 E2FF8F12
# Force kernel to load rootfs
# skip_initramfs -> want_initramfs
./magiskboot hexpatch kernel \
736B69705F696E697472616D667300 \
77616E745F696E697472616D667300
fi
##########################################################################################
# Repack and flash
##########################################################################################
ui_print "- Repacking boot image"
./magiskboot repack "$BOOTIMAGE" || abort "! Unable to repack boot image!"
# Sign chromeos boot
$CHROMEOS && sign_chromeos
# Reset any error code
true