#!/usr/bin/env python3 #============================================================================ # #/** @file qgpt.py # # GENERAL DESCRIPTION # Generates QCom GPT header for wrapping Bootblock # # Copyright (c) 2018, The Linux Foundation. All rights reserved. # # SPDX-License-Identifier: BSD-3-Clause #**/ # import os import math import random import re import struct import sys import tempfile from binascii import crc32 from optparse import OptionParser from types import * def UpdateMBR(options, GPTBlobBuffer): i = 0x1BE GPTBlobBuffer[i + 0] = 0x00 # not bootable GPTBlobBuffer[i + 1] = 0x00 # head GPTBlobBuffer[i + 2] = 0x01 # sector GPTBlobBuffer[i + 3] = 0x00 # cylinder GPTBlobBuffer[i + 4] = 0xEE # type GPTBlobBuffer[i + 5] = 0xFF # head GPTBlobBuffer[i + 6] = 0xFF # sector GPTBlobBuffer[i + 7] = 0xFF # cylinder GPTBlobBuffer[i + 8:i + 8 + 4] = [0x01, 0x00, 0x00, 0x00] GPTBlobBuffer[i + 12:i + 16] = [0x00, 0x0f, 0x00, 0x00] # magic byte for MBR partitioning - always at this location regardless of # options.sector GPTBlobBuffer[510:512] = [0x55, 0xAA] return i def UpdatePartitionEntry(options, GPTBlobBuffer): i = 2 * options.sector_size # GUID of Boot Block GPTBlobBuffer[i:i + 16] = [0x2c, 0xba, 0xa0, 0xde, 0xdd, 0xcb, 0x05, 0x48, 0xb4, 0xf9, 0xf4, 0x28, 0x25, 0x1c, 0x3e, 0x98] i += 16 #This is to set Unique Partition GUID. Below Hex Value is : 00ChezaBootblock00 GPTBlobBuffer[i:i + 16] = [0x00, 0x43, 0x68, 0x65, 0x7a, 0x61, 0x42, 0x6f, 0x6f, 0x74, 0x62, 0x6c, 0x6f, 0x63, 0x6b, 0x00] i += 16 # LBA of BootBlock Start Content GPTBlobBuffer[i:i + 8] = [0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] i += 8 # End LBA of BootBlock Content GPTBlobBuffer[i] = options.end_lba & 0xFF GPTBlobBuffer[i+1] = (options.end_lba>>8) & 0xFF GPTBlobBuffer[i+2] = (options.end_lba>>16) & 0xFF GPTBlobBuffer[i+3] = (options.end_lba>>24) & 0xFF GPTBlobBuffer[i+4] = (options.end_lba>>32) & 0xFF GPTBlobBuffer[i+5] = (options.end_lba>>40) & 0xFF GPTBlobBuffer[i+6] = (options.end_lba>>48) & 0xFF GPTBlobBuffer[i+7] = (options.end_lba>>56) & 0xFF i += 8 # Attributes GPTBlobBuffer[i:i + 8] = [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] i += 8 # Label GPTBlobBuffer[i:i + 17] = [0x62, 0x00, 0x6f, 0x00, 0x6f, 0x00, 0x74, 0x00, 0x62, 0x00, 0x6c, 0x00, 0x6f, 0x00, 0x63, 0x00, 0x6b] return i def UpdateGPTHeader(options, GPTBlobBuffer): i = options.sector_size # Signature and Revision and HeaderSize i.e. "EFI PART" and 00 00 01 00 # and 5C 00 00 00 GPTBlobBuffer[i:i + 16] = [0x45, 0x46, 0x49, 0x20, 0x50, 0x41, 0x52, 0x54, 0x00, 0x00, 0x01, 0x00, 0x5C, 0x00, 0x00, 0x00] i += 16 # CRC is zeroed out till calculated later GPTBlobBuffer[i:i + 4] = [0x00, 0x00, 0x00, 0x00] i += 4 # Reserved, set to 0 GPTBlobBuffer[i:i + 4] = [0x00, 0x00, 0x00, 0x00] i += 4 # Current LBA GPTBlobBuffer[i:i + 8] = [0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] i += 8 # Backup LBA, No Backup Gpt Used GPTBlobBuffer[i:i + 8] = [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] i += 8 # First Usuable LBA (qc_sec + bootblock location) GPTBlobBuffer[i:i + 8] = [0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] i += 8 # Last Usuable LBA (qc_sec + bootblock end location) GPTBlobBuffer[i] = options.end_lba & 0xFF GPTBlobBuffer[i+1] = (options.end_lba>>8) & 0xFF GPTBlobBuffer[i+2] = (options.end_lba>>16) & 0xFF GPTBlobBuffer[i+3] = (options.end_lba>>24) & 0xFF GPTBlobBuffer[i+4] = (options.end_lba>>32) & 0xFF GPTBlobBuffer[i+5] = (options.end_lba>>40) & 0xFF GPTBlobBuffer[i+6] = (options.end_lba>>48) & 0xFF GPTBlobBuffer[i+7] = (options.end_lba>>56) & 0xFF i += 8 # GUID GPTBlobBuffer[i:i + 16] = [0x32,0x1B,0x10,0x98,0xE2,0xBB,0xF2,0x4B, 0xA0,0x6E,0x2B,0xB3,0x3D,0x00,0x0C,0x20] i += 16 # Partition Table Entry LBA GPTBlobBuffer[i:i + 8] = [0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] i += 8 # Number of Partition Entries GPTBlobBuffer[i:i + 4] = [0x01, 0x00, 0x00, 0x00] i += 4 # Size of One Partition Entry GPTBlobBuffer[i:i + 4] = [0x80, 0x00, 0x00, 0x00] i += 4 # CRC of Partition Entry PartEntry = GPTBlobBuffer[options.sector_size*2:options.sector_size*2 + 128] CalcEntryCRC = crc32(b''.join(struct.pack("B", x) for x in PartEntry)) GPTBlobBuffer[i] = CalcEntryCRC & 0xFF GPTBlobBuffer[i+1] = (CalcEntryCRC>>8) & 0xFF GPTBlobBuffer[i+2] = (CalcEntryCRC>>16) & 0xFF GPTBlobBuffer[i+3] = (CalcEntryCRC>>24) & 0xFF i += 4 # CRC of Partition Table Header GPTHeader = GPTBlobBuffer[options.sector_size:options.sector_size + 92] CalcEntryCRC = crc32(b''.join(struct.pack("B", x) for x in GPTHeader)) i = options.sector_size + 16 GPTBlobBuffer[i] = CalcEntryCRC & 0xFF GPTBlobBuffer[i+1] = (CalcEntryCRC>>8) & 0xFF GPTBlobBuffer[i+2] = (CalcEntryCRC>>16) & 0xFF GPTBlobBuffer[i+3] = (CalcEntryCRC>>24) & 0xFF return i if __name__ == '__main__': usage = 'usage: %prog [OPTIONS] INFILE OUTFILE\n\n' + \ 'Packages IMAGE in a GPT format.' parser = OptionParser(usage) parser.add_option('-s', type="int", dest='sector_size', default=4096, help='Sector size in bytes [Default:4096(4KB)]', metavar='SIZE') (options, args) = parser.parse_args() if len(args) != 2: print("Invalid arguments! Exiting...\n") parser.print_help() sys.exit(1) if options.sector_size != 4096 and options.sector_size != 512: print("Invalid Sector Size") sys.exit(1) options.inputfile = args[0] options.outputfile = args[1] with open(options.inputfile, 'rb+') as fin: bb_buffer = fin.read() # Round up to next sector if bootblock size not evenly divisible options.end_lba = ((len(bb_buffer) + options.sector_size - 1) // options.sector_size) # Add 3 sectors for MBR, GPT header and GPT partition entry options.end_lba += 3 # Subtract one because this is last usable LBA, not amount of LBAs options.end_lba -= 1 GPTBlobBuffer = [0] * (options.sector_size*3) #Size of MBR+GPT+PART_ENTRY UpdateMBR(options, GPTBlobBuffer) UpdatePartitionEntry(options, GPTBlobBuffer) UpdateGPTHeader(options, GPTBlobBuffer) with open(options.outputfile, 'wb') as fout: for b in GPTBlobBuffer: fout.write(struct.pack("B", b)) fout.write(bb_buffer)