Magisk/scripts/boot_patch.sh
2021-01-18 12:37:08 -08:00

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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, RECOVERYMODE
#
# 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 image for Magisk.
# (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 required for this script
# to work properly
# magiskinit binary The binary to replace /init; magisk binary embedded
# magiskboot binary A tool to manipulate boot images
# chromeos folder This folder includes all the utilities and keys to sign
# (optional) chromeos boot images. Currently only used for Pixel C
#
###########################################################################################
############
# Functions
############
# Pure bash dirname implementation
getdir() {
case "$1" in
*/*)
dir=${1%/*}
if [ -z $dir ]; then
echo "/"
else
echo $dir
fi
;;
*) 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
# Check if 64-bit
[ -d /system/lib64 ] && IS64BIT=true || IS64BIT=false
fi
BOOTIMAGE="$1"
[ -e "$BOOTIMAGE" ] || abort "$BOOTIMAGE does not exist!"
# Flags
[ -z $KEEPVERITY ] && KEEPVERITY=false
[ -z $KEEPFORCEENCRYPT ] && KEEPFORCEENCRYPT=false
[ -z $RECOVERYMODE ] && RECOVERYMODE=false
export KEEPVERITY
export KEEPFORCEENCRYPT
chmod -R 755 .
#########
# Unpack
#########
CHROMEOS=false
ui_print "- Unpacking boot image"
./magiskboot unpack "$BOOTIMAGE"
case $? in
1 )
abort "! Unsupported/Unknown image format"
;;
2 )
ui_print "- ChromeOS boot image detected"
CHROMEOS=true
;;
esac
[ -f recovery_dtbo ] && RECOVERYMODE=true
###################
# Ramdisk Restores
###################
# Test patch status and do restore
ui_print "- Checking ramdisk status"
if [ -e ramdisk.cpio ]; then
./magiskboot cpio ramdisk.cpio test
STATUS=$?
else
# Stock A only system-as-root
STATUS=0
fi
case $((STATUS & 3)) in
0 ) # Stock boot
ui_print "- Stock boot image detected"
SHA1=`./magiskboot sha1 "$BOOTIMAGE" 2>/dev/null`
cat $BOOTIMAGE > stock_boot.img
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 $SHA1 ] && SHA1=`./magiskboot cpio ramdisk.cpio sha1 2>/dev/null`
./magiskboot cpio ramdisk.cpio restore
cp -af ramdisk.cpio ramdisk.cpio.orig
;;
2 ) # Unsupported
ui_print "! Boot image patched by unsupported programs"
abort "! Please restore back to stock boot image"
;;
esac
##################
# Ramdisk Patches
##################
ui_print "- Patching ramdisk"
echo "KEEPVERITY=$KEEPVERITY" > config
echo "KEEPFORCEENCRYPT=$KEEPFORCEENCRYPT" >> config
echo "RECOVERYMODE=$RECOVERYMODE" >> config
[ ! -z $SHA1 ] && echo "SHA1=$SHA1" >> config
# Compress to save precious ramdisk space
./magiskboot compress=xz magisk32 magisk32.xz
./magiskboot compress=xz magisk64 magisk64.xz
$IS64BIT && SKIP64="" || SKIP64="#"
./magiskboot cpio ramdisk.cpio \
"add 0750 init magiskinit" \
"mkdir 0750 overlay.d" \
"mkdir 0750 overlay.d/sbin" \
"add 0644 overlay.d/sbin/magisk32.xz magisk32.xz" \
"$SKIP64 add 0644 overlay.d/sbin/magisk64.xz magisk64.xz" \
"patch" \
"backup ramdisk.cpio.orig" \
"mkdir 000 .backup" \
"add 000 .backup/.magisk config"
rm -f ramdisk.cpio.orig config magisk*.xz
#################
# Binary Patches
#################
for dt in dtb kernel_dtb extra; do
[ -f $dt ] && ./magiskboot dtb $dt patch && ui_print "- Patch fstab in $dt"
done
if [ -f kernel ]; then
# Remove Samsung RKP
./magiskboot hexpatch kernel \
49010054011440B93FA00F71E9000054010840B93FA00F7189000054001840B91FA00F7188010054 \
A1020054011440B93FA00F7140020054010840B93FA00F71E0010054001840B91FA00F7181010054
# Remove Samsung defex
# Before: [mov w2, #-221] (-__NR_execve)
# After: [mov w2, #-32768]
./magiskboot hexpatch kernel 821B8012 E2FF8F12
# Force kernel to load rootfs
# skip_initramfs -> want_initramfs
./magiskboot hexpatch kernel \
736B69705F696E697472616D667300 \
77616E745F696E697472616D667300
fi
#################
# Repack & Flash
#################
ui_print "- Repacking boot image"
./magiskboot repack "$BOOTIMAGE" || abort "! Unable to repack boot image!"
# Sign chromeos boot
$CHROMEOS && sign_chromeos
# Reset any error code
true