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#
# Copyright 2024 WebAssembly Community Group participants
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
'''
Wasm extractor for testcases generated by the ClusterFuzz run.py script. Usage:
extract_wasms.py INFILE.js OUTFILE
That will find embedded wasm files in INFILE.js, of the form
var .. = new Uint8Array([..wasm_contents..]);
and extract them into OUTFILE.0.wasm, OUTFILE.1.wasm, etc. It also emits
OUTFILE.js which will no longer contain the embedded contents, after which the
script can be run as
d8 OUTFILE.js -- OUTFILE.0.wasm
That is, the embedded file can now be provided as a filename argument.
'''
import re
import sys
file_counter = 0
def get_wasm_filename():
global file_counter
file_counter += 1
return f'{out}.{file_counter - 1}.wasm'
in_js = sys.argv[1]
out = sys.argv[2]
with open(in_js) as f:
js = f.read()
def repl(text):
# We found something of the form
#
# var binary = new Uint8Array([..binary data as numbers..]);
#
# Parse out the numbers into a binary wasm file.
numbers = text.groups()[0]
numbers = numbers.split(',')
numbers = [int(n) for n in numbers]
with open(get_wasm_filename(), 'wb') as f:
f.write(bytes(numbers))
# Replace it with nothing.
return ''
# Replace the wasm files and write them out.
js = re.sub(r'var \w+ = new Uint8Array\(\[([\d,]+)\]\);', repl, js)
# Write out the new JS.
with open(f'{out}.js', 'w') as f:
f.write(js)
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