gitcoin miner

miner.py

#!/usr/bin/env python
import calendar
import datetime
import hashlib
import multiprocessing
import os
import re
import signal
import subprocess
import sys

CORES = multiprocessing.cpu_count()
USERNAME = 'user-iguqnxej'
CLONE_URL = 'lvl1-jtdjmntc@stripe-ctf.com:current-round'
# CLONE_URL = 'lvl1-jtdjmntc@stripe-ctf.com:level1'

COMMIT_FORMAT = """tree {}
parent {}
author jdp <jp@i.tv> {} +0000
committer jdp <jp@.itv> {} +0000

"""

local_repo = CLONE_URL.split(':')[-1]


def prepare_index():
    with open('LEDGER.txt') as f:
        ledger = f.read()

    pattern = '{}: (\d+)'.format(USERNAME)
    match = re.search(pattern, ledger)
    if match:
        gitcoins = int(match.groups()[0]) + 1
        ledger = re.sub(pattern, '{}: {}'.format(USERNAME, gitcoins), ledger)
    else:
        ledger += '{}: 1\n'.format(USERNAME)

    with open('LEDGER.txt', 'w') as f:
        f.write(ledger)

    subprocess.call(['git', 'add', 'LEDGER.txt'])


def solve(solver_id, repo_lock, commit_queue):
    print "solver", solver_id, "at work!"
    repo_lock.acquire()
    tree_hex = subprocess.check_output(['git', 'write-tree']).strip()
    parent_hex = subprocess.check_output(['git', 'rev-parse', 'HEAD']).strip()
    repo_lock.release()
    timestamp = calendar.timegm(datetime.datetime.utcnow().utctimetuple())
    commit = COMMIT_FORMAT.format(tree_hex, parent_hex, timestamp, timestamp)

    with open('difficulty.txt') as f:
        difficulty = f.read().strip()

    counter = solver_id
    while True:
        h = hashlib.sha1()
        contents = commit + str(counter)
        header = "commit " + str(len(contents)) + "\0"
        h.update(header + contents)
        sha1 = h.hexdigest()
        if sha1 < difficulty:
            commit_queue.put((solver_id, sha1, contents))
        counter += CORES


def submit(repo_lock, commit_queue):
    while True:
        solver_id, sha1, contents = commit_queue.get()
        print "mined a gitcoin!", sha1, "from", solver_id
        repo_lock.acquire()
        p = subprocess.Popen(['git', 'hash-object', '-t', 'commit', '--stdin', '-w'], stdin=subprocess.PIPE)
        p.communicate(contents)
        subprocess.call(['git', 'reset', '--hard', sha1])
        result = subprocess.call(['git', 'push', 'origin', 'master'])
        subprocess.call(['git', 'fetch', 'origin', 'master'])
        subprocess.call(['git', 'reset', '--hard', 'origin/master'])
        repo_lock.release()


def init_worker():
    signal.signal(signal.SIGINT, signal.SIG_IGN)


if __name__ == '__main__':
    print "starting up..."
    if not os.path.isdir(local_repo):
        print "cloning git repo..."
        subprocess.call(['git', 'clone', CLONE_URL])

    os.chdir(local_repo)

    prepare_index()
    manager = multiprocessing.Manager()
    repo_lock = manager.Lock()
    commit_queue = manager.Queue()

    try:
        producer_pool = multiprocessing.Pool(CORES, init_worker)
        for i in range(CORES):
            producer_pool.apply_async(solve, (i, repo_lock, commit_queue))
        producer_pool.close()
        consumer = multiprocessing.Process(target=submit, args=(repo_lock, commit_queue))
        consumer.start()

        producer_pool.join()
        consumer.join()
    except KeyboardInterrupt:
        producer_pool.terminate()
        producer_pool.join()
        consumer.terminate()
        consumer.join()
        sys.exit(0)
    if submit():
        print "success!"