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import contextlib
import os
import struct
import sys
import tempfile
import uuid
from macholib import MachO, mach_o
if sys.version_info[:2] <= (2, 6):
import unittest2 as unittest
else:
import unittest
@contextlib.contextmanager
def temporary_macho_file(load_commands):
struct_mach_header_64_format = ">IIIIIIII"
cpu_type_arm64 = 0x100000C
cpu_subtype_arm_all = 0x0
mh_filetype_execute = 0x2
ncmds = len(load_commands)
sizeofcmds = sum([len(lc) for lc in load_commands])
mach_header = struct.pack(
struct_mach_header_64_format,
mach_o.MH_MAGIC_64,
cpu_type_arm64,
cpu_subtype_arm_all,
mh_filetype_execute,
ncmds,
sizeofcmds,
0,
0,
)
with tempfile.NamedTemporaryFile(delete=False) as macho_file:
macho_file.write(mach_header)
for lc in load_commands:
macho_file.write(lc)
# Close the file so it can be re-opened on Windows.
macho_file.close()
yield macho_file.name
os.unlink(macho_file.name)
def lc_uuid(macho_uuid):
lc_uuid_format = ">II16s"
lc_uuid_size = struct.calcsize(lc_uuid_format)
return struct.pack(lc_uuid_format, mach_o.LC_UUID, lc_uuid_size, macho_uuid.bytes)
def lc_unknown():
lc_unknown_format = ">III"
lc_unknown = 0x707A11ED # Made-up load command. Hopefully never used.
lc_unknown_size = struct.calcsize(lc_unknown_format)
lc_unknown_value = 42 # Random value
return struct.pack(lc_unknown_format, lc_unknown, lc_unknown_size, lc_unknown_value)
class TestMachO(unittest.TestCase):
def test_known_load_command_should_succeed(self):
macho_uuid = uuid.UUID("6894C0AE-C8B7-4E0B-A529-30BBEBA3703B")
with temporary_macho_file([lc_uuid(macho_uuid)]) as macho_filename:
macho = MachO.MachO(macho_filename, allow_unknown_load_commands=True)
self.assertEqual(len(macho.headers), 1)
self.assertEqual(len(macho.headers[0].commands), 1)
load_command, command, _ = macho.headers[0].commands[0]
self.assertEqual(load_command.cmd, mach_o.LC_UUID)
self.assertEqual(uuid.UUID(bytes=command.uuid), macho_uuid)
def test_unknown_load_command_should_fail(self):
with temporary_macho_file([lc_unknown()]) as macho_filename:
with self.assertRaises(ValueError) as assert_context:
MachO.MachO(macho_filename)
def test_unknown_load_command_should_succeed_with_flag(self):
with temporary_macho_file([lc_unknown()]) as macho_filename:
macho = MachO.MachO(macho_filename, allow_unknown_load_commands=True)
self.assertEqual(len(macho.headers), 1)
self.assertEqual(len(macho.headers[0].commands), 1)
load_command, command, data = macho.headers[0].commands[0]
self.assertEqual(load_command.cmd, 0x707A11ED)
self.assertIsInstance(command, mach_o.load_command)
self.assertEqual(struct.unpack(">I", data), (42,))
def test_mix_of_known_and_unknown_load_commands_should_allow_unknown_with_flag(
self,
):
macho_uuid = uuid.UUID("6894C0AE-C8B7-4E0B-A529-30BBEBA3703B")
with temporary_macho_file(
[lc_unknown(), lc_uuid(macho_uuid)]
) as macho_filename:
macho = MachO.MachO(macho_filename, allow_unknown_load_commands=True)
self.assertEqual(len(macho.headers), 1)
self.assertEqual(len(macho.headers[0].commands), 2)
load_command, command, data = macho.headers[0].commands[0]
self.assertEqual(load_command.cmd, 0x707A11ED)
self.assertIsInstance(command, mach_o.load_command)
self.assertEqual(struct.unpack(">I", data), (42,))
load_command, command, _ = macho.headers[0].commands[1]
self.assertEqual(load_command.cmd, mach_o.LC_UUID)
self.assertEqual(uuid.UUID(bytes=command.uuid), macho_uuid)
if __name__ == "__main__":
unittest.main()
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