sm64ex-coop/tools/patch_libmalloc.py

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2020-02-03 06:51:26 +01:00
#!/usr/bin/env python
#
# Patches the malloc() function in libmalloc.so to allocate more than the
# specified number of bytes. This is needed to work around issues with the
# compiler occasionally crashing.
#
# This script replaces the "move a1, a0" (00 80 28 25) instruction with
# "addiu a1, a0, n" (24 85 nn nn), which causes the malloc function to add n to
# the size parameter that was passed in.
import hashlib
import os.path
import sys
# file to patch
filename = 'tools/ido5.3_compiler/lib/libmalloc.so'
# Expected (unpatched) hash of file
filehash = 'adde672b5d79b52ca3cce9a47c7cb648'
# location in file to patch
address = 0xAB4
# Get parameter
if len(sys.argv) != 2:
print('Usage: ' + sys.argv[0] + ' n\n where n is the number of extra bytes to allocate in malloc()')
exit(1)
n = int(sys.argv[1])
# Original instruction "move a1, a0"
oldinsn = bytearray([0x00, 0x80, 0x28, 0x25])
# New instruction "addiu a1, a0, n"
newinsn = bytearray([0x24, 0x85, (n >> 8) & 0xFF, (n & 0xFF)])
# Patch the file
try:
with open(filename, 'rb+') as f:
# Read file contents
contents = bytearray(f.read())
# Unpatch the file by restoring original instruction
contents[address:address+4] = oldinsn
# Verify the (unpatched) hash of the file
md5 = hashlib.md5()
md5.update(contents)
if md5.hexdigest() != filehash:
print('Error: ' + filename + ' does not appear to be the correct version.')
exit(1)
# Patch the file
if n != 0:
contents[address:address+4] = newinsn
# Write file
f.seek(0, os.SEEK_SET)
f.write(contents)
except IOError as e:
print('Error: Could not open library file for writing: ' + str(e))