gecko-dev/js/xpconnect/loader/script_cache.py

93 lines
2.4 KiB
Python
Executable File

#!/usr/bin/env python
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this file,
# You can obtain one at http://mozilla.org/MPL/2.0/.
import io
import os
import struct
import sys
MAGIC = b"mozXDRcachev002\0"
def usage():
print(
"""Usage: script_cache.py <file.bin> ...
Decodes and prints out the contents of a startup script cache file
(e.g., startupCache/scriptCache.bin) in human-readable form."""
)
sys.exit(1)
class ProcessTypes:
Uninitialized = 0
Parent = 1
Web = 2
Extension = 3
Privileged = 4
def __init__(self, val):
self.val = val
def __str__(self):
res = []
if self.val & (1 << self.Uninitialized):
raise Exception("Uninitialized process type")
if self.val & (1 << self.Parent):
res.append("Parent")
if self.val & (1 << self.Web):
res.append("Web")
if self.val & (1 << self.Extension):
res.append("Extension")
if self.val & (1 << self.Privileged):
res.append("Privileged")
return "|".join(res)
class InputBuffer(object):
def __init__(self, data):
self.data = data
self.offset = 0
@property
def remaining(self):
return len(self.data) - self.offset
def unpack(self, fmt):
res = struct.unpack_from(fmt, self.data, self.offset)
self.offset += struct.calcsize(fmt)
return res
def unpack_str(self):
(size,) = self.unpack("<H")
res = self.data[self.offset : self.offset + size].decode("utf-8")
self.offset += size
return res
if len(sys.argv) < 2 or not os.path.exists(sys.argv[1]):
usage()
for filename in sys.argv[1:]:
with io.open(filename, "rb") as f:
magic = f.read(len(MAGIC))
if magic != MAGIC:
raise Exception("Bad magic number")
(hdrSize,) = struct.unpack("<I", f.read(4))
hdr = InputBuffer(f.read(hdrSize))
i = 0
while hdr.remaining:
i += 1
print("{}: {}".format(i, hdr.unpack_str()))
print(" Key: {}".format(hdr.unpack_str()))
print(" Offset: {:>9,}".format(*hdr.unpack("<I")))
print(" Size: {:>9,}".format(*hdr.unpack("<I")))
print(" Processes: {}".format(ProcessTypes(*hdr.unpack("B"))))
print("")