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#!/usr/bin/env python3
#
# Copyright (c) 2018, the Dart project authors. Please see the AUTHORS file
# for details. All rights reserved. Use of this source code is governed by a
# BSD-style license that can be found in the LICENSE file.
import argparse
from ctypes import create_string_buffer
from struct import *
# FILE HEADER FLAGS
FILE_HEADER_RELFLG = 0x1 # No relocation information
FILE_HEADER_EXEC = 0x2 # Executable
FILE_HEADER_LNNO = 0x4 # No line number information
FILE_HEADER_LSYMS = 0x8 # Local symbols removed / not present
FILE_HEADER_AR32WR = 0x100 # File is 32-bit little endian
# SECTION HEADER FLAGS
SECTION_HEADER_TEXT = 0x20 # Contains executable code
SECTION_HEADER_DATA = 0x40 # Contains only initialized data
SECTION_HEADER_BSS = 0x80 # Contains uninitialized data
# FILE HEADER FORMAT
# typedef struct {
# unsigned short f_magic; /* magic number */
# unsigned short f_nscns; /* number of sections */
# unsigned long f_timdat; /* time & date stamp */
# unsigned long f_symptr; /* file pointer to symtab */
# unsigned long f_nsyms; /* number of symtab entries */
# unsigned short f_opthdr; /* sizeof(optional hdr) */
# unsigned short f_flags; /* flags */
# } FILHDR;
FILE_HEADER_FORMAT = 'HHIIIHH'
FILE_HEADER_SIZE = calcsize(FILE_HEADER_FORMAT)
FILE_HEADER_MAGICS = {
'x86': 0x014c,
'x64': 0x8664,
'arm': 0x1c0,
'arm64': 0xaa64,
'riscv32': 0x5032,
'riscv64': 0x5064,
}
FILE_HEADER_NUM_SECTIONS = 1
FILE_HEADER_TIMESTAMP = 0
FILE_HEADER_SIZE_OF_OPTIONAL = 0
FILE_HEADER_FLAGS = FILE_HEADER_LNNO
# SECTION HEADER FORMAT
# typedef struct {
# char s_name[8]; /* section name */
# unsigned long s_paddr; /* physical address, aliased s_nlib */
# unsigned long s_vaddr; /* virtual address */
# unsigned long s_size; /* section size */
# unsigned long s_scnptr; /* file ptr to raw data for section */
# unsigned long s_relptr; /* file ptr to relocation */
# unsigned long s_lnnoptr; /* file ptr to line numbers */
# unsigned short s_nreloc; /* number of relocation entries */
# unsigned short s_nlnno; /* number of line number entries */
# unsigned long s_flags; /* flags */
# } SCNHDR;
SECTION_HEADER_FORMAT = '8sIIIIIIHHI'
SECTION_HEADER_SIZE = calcsize(SECTION_HEADER_FORMAT)
SECTION_NAME_RODATA = b'.rodata'
SECTION_NAME_TEXT = b'.text'
SECTION_PADDR = 0x0
SECTION_VADDR = 0x0
SECTION_RAW_DATA_PTR = (
FILE_HEADER_SIZE + FILE_HEADER_NUM_SECTIONS * SECTION_HEADER_SIZE)
SECTION_RELOCATION_PTR = 0x0
SECTION_LINE_NUMS_PTR = 0x0
SECTION_NUM_RELOCATION = 0
SECTION_NUM_LINE_NUMS = 0
# SYMBOL TABLE FORMAT
# typedef struct {
# union {
# char e_name[8];
# struct {
# unsigned long e_zeroes;
# unsigned long e_offset;
# } e;
# } e;
# unsigned long e_value;
# short e_scnum;
# unsigned short e_type;
# unsigned char e_sclass;
# unsigned char e_numaux;
# } SYMENT;
SYMBOL_TABLE_ENTRY_SHORT_LEN = 8
SYMBOL_TABLE_ENTRY_FORMAT_SHORT = '8sIhHBB'
SYMBOL_TABLE_ENTRY_FORMAT_LONG = 'IIIhHBB'
SYMBOL_TABLE_ENTRY_SIZE = calcsize(SYMBOL_TABLE_ENTRY_FORMAT_SHORT)
SYMBOL_TABLE_ENTRY_ZEROS = 0x0
SYMBOL_TABLE_ENTRY_SECTION = 1
SYMBOL_TABLE_ENTRY_TYPE = 0
SYMBOL_TABLE_ENTRY_CLASS = 2 # External (public) symbol.
SYMBOL_TABLE_ENTRY_NUM_AUX = 0 # Number of auxiliary entries.
STRING_TABLE_OFFSET = 0x4 # Starting offset for the string table.
SIZE_FORMAT = 'I'
SIZE_LENGTH = calcsize(SIZE_FORMAT)
SIZE_SYMBOL_FORMAT_X64 = 'Q'
SIZE_SYMBOL_LENGTH_X64 = calcsize(SIZE_SYMBOL_FORMAT_X64)
def main():
parser = argparse.ArgumentParser(
description='Generate a COFF file for binary data.')
parser.add_argument('--input', dest='input', help='Path of the input file.')
parser.add_argument(
'--output', dest='output', help='Name of the output file.')
parser.add_argument(
'--symbol_name',
dest='symbol_name',
help='Name of the symbol for the binary data')
parser.add_argument(
'--size_symbol_name',
dest='size_name',
help='Name of the symbol for the size of the binary data')
parser.add_argument('--arch', dest='arch')
parser.add_argument(
'--executable', dest='executable', action='store_true', default=False)
args = parser.parse_args()
use_64_bit = args.arch in ['x64', 'arm64', 'riscv64']
with open(args.input, 'rb') as f:
section_data = f.read()
# We need to calculate the following to determine the size of our buffer:
# 1) Size of the data
# 2) Total length of the symbol strings which are over 8 characters
section_size = len(section_data)
includes_size_name = (args.size_name != None)
# Symbols on x86 are prefixed with '_'
symbol_prefix = b'_' if args.arch == 'x86' else b''
num_symbols = 2 if includes_size_name else 1
symbol_name = symbol_prefix + args.symbol_name.encode()
size_symbol_name = None
if (includes_size_name):
size_symbol = args.size_name if args.size_name else args.symbol_name + "Size"
size_symbol_name = symbol_prefix + size_symbol.encode()
size_symbol_format = SIZE_SYMBOL_FORMAT_X64 if use_64_bit else SIZE_FORMAT
size_symbol_size = SIZE_SYMBOL_LENGTH_X64 if use_64_bit else SIZE_LENGTH
# The symbol table is directly after the data section
symbol_table_ptr = (FILE_HEADER_SIZE + SECTION_HEADER_SIZE + section_size +
size_symbol_size)
string_table_len = 0
# Symbols longer than 8 characters have their string representations stored
# in the string table.
long_symbol_name = False
long_size_symbol_name = False
if (len(symbol_name) > SYMBOL_TABLE_ENTRY_SHORT_LEN):
string_table_len += len(symbol_name) + 1
long_symbol_name = True
if (includes_size_name and
(len(size_symbol_name) > SYMBOL_TABLE_ENTRY_SHORT_LEN)):
string_table_len += len(size_symbol_name) + 1
long_size_symbol_name = True
# Create the buffer and start building.
offset = 0
buff = create_string_buffer(
FILE_HEADER_SIZE + SECTION_HEADER_SIZE + section_size +
num_symbols * SYMBOL_TABLE_ENTRY_SIZE + SIZE_LENGTH + size_symbol_size +
string_table_len)
FILE_HEADER_MAGIC = FILE_HEADER_MAGICS[args.arch]
# Populate the file header. Basically constant except for the pointer to the
# beginning of the symbol table.
pack_into(FILE_HEADER_FORMAT, buff, offset, FILE_HEADER_MAGIC,
FILE_HEADER_NUM_SECTIONS, FILE_HEADER_TIMESTAMP, symbol_table_ptr,
num_symbols, FILE_HEADER_SIZE_OF_OPTIONAL, FILE_HEADER_FLAGS)
offset += FILE_HEADER_SIZE
section_name = SECTION_NAME_RODATA
section_type = SECTION_HEADER_DATA
if args.executable:
section_name = SECTION_NAME_TEXT
section_type = SECTION_HEADER_TEXT
# Populate the section header for a single section.
pack_into(SECTION_HEADER_FORMAT, buff, offset, section_name, SECTION_PADDR,
SECTION_VADDR, section_size + size_symbol_size,
SECTION_RAW_DATA_PTR, SECTION_RELOCATION_PTR,
SECTION_LINE_NUMS_PTR, SECTION_NUM_RELOCATION,
SECTION_NUM_LINE_NUMS, section_type)
offset += SECTION_HEADER_SIZE
# Copy the binary data.
buff[offset:offset + section_size] = section_data
offset += section_size
# Append the size of the section.
pack_into(size_symbol_format, buff, offset, section_size)
offset += size_symbol_size
# Build the symbol table. If a symbol name is 8 characters or less, it's
# placed directly in the symbol table. If not, it's entered in the string
# table immediately after the symbol table.
string_table_offset = STRING_TABLE_OFFSET
if long_symbol_name:
pack_into(SYMBOL_TABLE_ENTRY_FORMAT_LONG, buff, offset,
SYMBOL_TABLE_ENTRY_ZEROS, string_table_offset, 0x0,
SYMBOL_TABLE_ENTRY_SECTION, SYMBOL_TABLE_ENTRY_TYPE,
SYMBOL_TABLE_ENTRY_CLASS, SYMBOL_TABLE_ENTRY_NUM_AUX)
string_table_offset += len(symbol_name) + 1
else:
pack_into(SYMBOL_TABLE_ENTRY_FORMAT_SHORT, buff, offset, symbol_name,
0x0, SYMBOL_TABLE_ENTRY_SECTION, SYMBOL_TABLE_ENTRY_TYPE,
SYMBOL_TABLE_ENTRY_CLASS, SYMBOL_TABLE_ENTRY_NUM_AUX)
offset += SYMBOL_TABLE_ENTRY_SIZE
if includes_size_name:
# The size symbol table entry actually contains the value for the size.
if long_size_symbol_name:
pack_into(SYMBOL_TABLE_ENTRY_FORMAT_LONG, buff, offset,
SYMBOL_TABLE_ENTRY_ZEROS, string_table_offset,
section_size, SYMBOL_TABLE_ENTRY_SECTION,
SYMBOL_TABLE_ENTRY_TYPE, SYMBOL_TABLE_ENTRY_CLASS,
SYMBOL_TABLE_ENTRY_NUM_AUX)
else:
pack_into(SYMBOL_TABLE_ENTRY_FORMAT_SHORT, buff, offset,
symbol_name, section_size, SYMBOL_TABLE_ENTRY_SECTION,
SYMBOL_TABLE_ENTRY_TYPE, SYMBOL_TABLE_ENTRY_CLASS,
SYMBOL_TABLE_ENTRY_NUM_AUX)
offset += SYMBOL_TABLE_ENTRY_SIZE
pack_into(SIZE_FORMAT, buff, offset, string_table_len + SIZE_LENGTH)
offset += SIZE_LENGTH
# Populate the string table for any symbols longer than 8 characters.
if long_symbol_name:
symbol_len = len(symbol_name)
buff[offset:offset + symbol_len] = symbol_name
offset += symbol_len
buff[offset] = b'\0'
offset += 1
if includes_size_name and long_size_symbol_name:
symbol_len = len(size_symbol_name)
buff[offset:offset + symbol_len] = size_symbol_name
offset += symbol_len
buff[offset] = b'\0'
offset += 1
with open(args.output, 'wb') as f:
f.write(buff.raw)
if __name__ == '__main__':
main()