python/rox/suchild.py

   1 """This is the child program run by the su module. Do not import this module."""
   2 import os, sys
   3 import cPickle as pickle
   4 import time
   5 import shutil
   6
   7 import proxy
   8
   9 read_watches = []
  10 write_watches = []
  11 streams = {}
  12
  13 class Watch:
  14         """Contains a file descriptor and a function to call when it's ready"""
  15         def __init__(self, fd, fn):
  16                 self.fd = fd
  17                 self.ready = fn
  18
  19         def fileno(self):
  20                 return self.fd
  21
  22 class SuSlave(proxy.SlaveProxy):
  23         """A simple implementation of SlaveProxy that doesn't use gtk"""
  24         def __init__(self, to_parent, from_parent, slave):
  25                 self.read_watch = Watch(from_parent, self.read_ready)
  26                 self.write_watch = Watch(to_parent, self.write_ready)
  27                 proxy.SlaveProxy.__init__(self, to_parent, from_parent, slave)
  28
  29         def enable_read_watch(self):
  30                 assert self.read_watch not in read_watches
  31                 read_watches.append(self.read_watch)
  32
  33         def enable_write_watch(self):
  34                 assert self.write_watch not in write_watches
  35                 write_watches.append(self.write_watch)
  36
  37 class Slave:
  38         """This object runs as another user. Most methods behave in a similar
  39         way to the standard python methods of the same name."""
  40
  41         def spawnvpe(self, mode, file, args, env = None):
  42                 if env is None:
  43                         return os.spawnvp(mode, file, args)
  44                 else:
  45                         return os.spawnvpe(mode, file, args, env)
  46
  47         def waitpid(self, pid, flags):
  48                 return os.waitpid(pid, flags)
  49
  50         def getuid(self):
  51                 return os.getuid()
  52
  53         def setuid(self, uid):
  54                 return os.setuid(uid)
  55
  56         def rmtree(self, path):
  57                 return shutil.rmtree(path)
  58
  59         def unlink(self, path):
  60                 return os.unlink(path)
  61
  62         def open(self, path, mode = 'r'):
  63                 stream = file(path, mode)
  64                 streams[id(stream)] = stream
  65                 return id(stream)
  66
  67         def close(self, stream):
  68                 streams[stream].close()
  69                 del streams[stream]
  70
  71         def read(self, stream, length = 0):
  72                 return streams[stream].read(length)
  73
  74         def write(self, stream, data):
  75                 return streams[stream].write(data)
  76
  77         def rename(self, old, new):
  78                 return os.rename(old, new)
  79
  80         def chmod(self, path, mode):
  81                 return os.chmod(path, mode)
  82
  83 if __name__ == '__main__':
  84         from select import select
  85
  86         to_parent, from_parent = map(int, sys.argv[1:])
  87
  88         sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(sys.argv[0]))))
  89
  90         slave_proxy = SuSlave(to_parent, from_parent, Slave())
  91
  92         while read_watches or write_watches:
  93                 readable, writable = select(read_watches, write_watches, [])[:2]
  94                 for w in readable:
  95                         if not w.ready():
  96                                 read_watches.remove(w)
  97                 for w in writable:
  98                         if not w.ready():
  99                                 write_watches.remove(w)