Answer for Problem Set#4

fuzzer.py

#! /usr/bin/python

# A simple test that modifies random bytes of an existing dump file created
# from mongodump and runs mongorestore against a running mongod process on
# the default port

import random
import string
import subprocess
import time

from subprocess import call

# Note: Edit the paths accordingly
MONGOD = ['/Users/ren/mongo//mongod', '--nojournal', '-vvvvv', '--logpath', 'log']
BSON_DUMP = '/Users/ren/mongo/dump/test/user.bson'
TEMP_DUMP = '/Users/ren/mongo/dump2/test/user.bson'

MONGO_RESTORE = ['/Users/ren/mongo/mongorestore', '--drop', TEMP_DUMP]

FUZZ_FACTOR = 20000
FUZZ_THRESH = FUZZ_FACTOR / 1000

num_tests = 10

mongod = subprocess.Popen(MONGOD)

for i in range(num_tests):
  with open(BSON_DUMP, 'r') as dump_file:
    with open(TEMP_DUMP, 'w') as temp_file:
      byte = dump_file.read(1)

      while byte != "":
        if random.randrange(FUZZ_FACTOR) >= FUZZ_THRESH:
          temp_file.write(byte)
        else:
          temp_file.write(chr(random.randrange(256)))

        byte = dump_file.read(1)

  ret_code = call(MONGO_RESTORE)
  #assert(ret_code == 0)

  time.sleep(5) # give time for mongod to die (if it actually crashes)
  assert(mongod.poll() is None)

mongod.terminate()
print('Test passed!')