text: # Copyright 2012 the V8 project authors. All rights reserved.
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are
  # met:
  #
  #     * Redistributions of source code must retain the above copyright
  #       notice, this list of conditions and the following disclaimer.
  #     * Redistributions in binary form must reproduce the above
  #       copyright notice, this list of conditions and the following
  #       disclaimer in the documentation and/or other materials provided
  #       with the distribution.
  #     * Neither the name of Google Inc. nor the names of its
  #       contributors may be used to endorse or promote products derived
  #       from this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  
  import base64
  import os
  import subprocess
  
  
  def ReadFileAndSignature(filename):
    with open(filename, "rb") as f:
      file_contents = base64.b64encode(f.read())
    signature_file = filename + ".signature"
    if (not os.path.exists(signature_file) or
        os.path.getmtime(signature_file) < os.path.getmtime(filename)):
      private_key = "~/.ssh/v8_dtest"
      code = subprocess.call("openssl dgst -out %s -sign %s %s" %
                             (signature_file, private_key, filename),
                             shell=True)
      if code != 0: return [None, code]
    with open(signature_file) as f:
      signature = base64.b64encode(f.read())
    return [file_contents, signature]
  
  
  def VerifySignature(filename, file_contents, signature, pubkeyfile):
    with open(filename, "wb") as f:
      f.write(base64.b64decode(file_contents))
    signature_file = filename + ".foreign_signature"
    with open(signature_file, "wb") as f:
      f.write(base64.b64decode(signature))
    code = subprocess.call("openssl dgst -verify %s -signature %s %s" %
                           (pubkeyfile, signature_file, filename),
                           shell=True)
    matched = (code == 0)
    if not matched:
      os.remove(signature_file)
      os.remove(filename)
    return matched
  