85 lines
1.9 KiB
Bash
Executable File
85 lines
1.9 KiB
Bash
Executable File
#!/bin/bash
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#build the bootloader image
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set -e
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if [ "$DEBUG" ]; then
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set -x
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fi
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print_help() {
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echo "Usage: ./build.sh path_to_shim"
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}
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check_deps() {
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local needed_commands="cpio binwalk pcregrep"
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for command in $needed_commands; do
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if ! command -v $command &> /dev/null; then
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echo $command
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fi
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done
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}
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create_loop() {
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local loop_device=$(losetup -f)
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losetup -P $loop_device "${1}"
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echo $loop_device
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}
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if [ "$EUID" -ne 0 ]; then
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echo "this needs to be run as root."
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exit 1
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fi
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if [ -z "$1" ]; then
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print_help
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exit 1
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fi
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missing_commands=$(check_deps)
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if [ "${missing_commands}" ]; then
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echo "You are missing dependencies needed for this script."
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echo "Commands needed:"
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echo "${missing_commands}"
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exit 1
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fi
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shim_path=$(realpath "${1}")
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echo "created loop device for shim"
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shim_loop=$(create_loop "${shim_path}")
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kernel_loop="${shim_loop}p2" #KERN-A should always be p2
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echo "copying shim kernel to new file in /tmp"
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kernel_dir=/tmp/shim_kernel
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rm -rf $kernel_dir
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mkdir $kernel_dir -p
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dd if=$kernel_loop of=$kernel_dir/kernel.bin bs=1M status=none
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echo "extracting data from kernel"
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previous_dir=$(pwd)
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cd $kernel_dir
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binwalk_out=$(binwalk --extract kernel.bin --run-as=root)
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#i can't be bothered to learn how to use sed
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extracted_file=$(echo $binwalk_out | pcregrep -o1 "\d+\s+0x([0-9A-F]+)\s+gzip compressed data")
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echo "extracting initramfs archive from kernel"
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cd _kernel.bin.extracted/
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binwalk --extract $extracted_file --run-as=root > /dev/null
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cd "_${extracted_file}.extracted/"
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cpio_file=$(file ./* | pcregrep -o1 "([0-9A-F]+):\s+ASCII cpio archive")
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echo "extracting initramfs cpio archive"
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initramfs_dir=/tmp/shim_initramfs
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rm -rf $initramfs_dir
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cat $cpio_file | cpio -D $initramfs_dir -imd --quiet
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echo "shim initramfs extracted to ${initramfs_dir}"
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#leave /tmp
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cd $previous_dir
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echo "patching initramfs"
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exec ./patch_initramfs.sh $initramfs_dir
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echo "cleaning up loop devices"
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losetup -d $shim_loop |