build/ios/clean_env.py

   1 #!/usr/bin/python
   2 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   3 # Use of this source code is governed by a BSD-style license that can be
   4 # found in the LICENSE file.
   5
   6 import os
   7 import sys
   8
   9 def Main(argv):
  10   """This is like 'env -i', but it uses a whitelist of env variables to allow
  11   through to the command being run.  It attempts to strip off Xcode-added
  12   values from PATH.
  13   """
  14   # Note: An attempt was made to do something like: env -i bash -lc '[command]'
  15   # but that fails to set the things set by login (USER, etc.), so instead
  16   # the only approach that seems to work is to have a whitelist.
  17   env_key_whitelist = (
  18     'HOME',
  19     'LOGNAME',
  20     # 'PATH' added below (but filtered).
  21     'PWD',
  22     'SHELL',
  23     'TEMP',
  24     'TMPDIR',
  25     'USER'
  26   )
  27
  28   # Need something to run.
  29   # TODO(lliabraa): Make this output a usage string and exit (here and below).
  30   assert(len(argv) > 0)
  31
  32   add_to_path = [];
  33   first_entry = argv[0];
  34   if first_entry.startswith('ADD_TO_PATH='):
  35     argv = argv[1:];
  36     add_to_path = first_entry.replace('ADD_TO_PATH=', '', 1).split(':')
  37
  38   # Still need something to run.
  39   assert(len(argv) > 0)
  40
  41   clean_env = {}
  42
  43   # Pull over the whitelisted keys.
  44   for key in env_key_whitelist:
  45     val = os.environ.get(key, None)
  46     if not val is None:
  47       clean_env[key] = val
  48
  49   # Collect the developer dir as set via Xcode, defaulting it.
  50   dev_prefix = os.environ.get('DEVELOPER_DIR', '/Developer/')
  51   if dev_prefix[-1:] != '/':
  52     dev_prefix += '/'
  53
  54   # Now pull in PATH, but remove anything Xcode might have added.
  55   initial_path = os.environ.get('PATH', '')
  56   filtered_chunks = \
  57       [x for x in initial_path.split(':') if not x.startswith(dev_prefix)]
  58   if filtered_chunks:
  59     clean_env['PATH'] = ':'.join(add_to_path + filtered_chunks)
  60
  61   # Add any KEY=VALUE args before the command to the cleaned environment.
  62   args = argv[:]
  63   while '=' in args[0]:
  64     (key, val) = args[0].split('=', 1)
  65     clean_env[key] = val
  66     args = args[1:]
  67
  68   # Still need something to run.
  69   assert(len(args) > 0)
  70
  71   # Off it goes...
  72   os.execvpe(args[0], args, clean_env)
  73   # Should never get here, so return a distinctive, non-zero status code.
  74   return 66
  75
  76 if __name__ == '__main__':
  77   sys.exit(Main(sys.argv[1:]))