ROX-Lib2/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 shutil
   4
   5 import proxy
   6
   7 read_watches = []
   8 write_watches = []
   9 streams = {}
  10
  11 class Watch:
  12         """Contains a file descriptor and a function to call when it's ready"""
  13         def __init__(self, fd, fn):
  14                 self.fd = fd
  15                 self.ready = fn
  16
  17         def fileno(self):
  18                 return self.fd
  19
  20 class SuSlave(proxy.SlaveProxy):
  21         """A simple implementation of SlaveProxy that doesn't use gtk"""
  22         def __init__(self, to_parent, from_parent, slave):
  23                 self.read_watch = Watch(from_parent, self.read_ready)
  24                 self.write_watch = Watch(to_parent, self.write_ready)
  25                 proxy.SlaveProxy.__init__(self, to_parent, from_parent, slave)
  26
  27         def enable_read_watch(self):
  28                 assert self.read_watch not in read_watches
  29                 read_watches.append(self.read_watch)
  30
  31         def enable_write_watch(self):
  32                 assert self.write_watch not in write_watches
  33                 write_watches.append(self.write_watch)
  34
  35 class Slave:
  36         """This object runs as another user. Most methods behave in a similar
  37         way to the standard python methods of the same name."""
  38
  39         def spawnvpe(self, mode, file, args, env = None):
  40                 if env is None:
  41                         return os.spawnvp(mode, file, args)
  42                 else:
  43                         return os.spawnvpe(mode, file, args, env)
  44
  45         def waitpid(self, pid, flags):
  46                 return os.waitpid(pid, flags)
  47
  48         def getuid(self):
  49                 return os.getuid()
  50
  51         def setuid(self, uid):
  52                 return os.setuid(uid)
  53
  54         def rmtree(self, path):
  55                 return shutil.rmtree(path)
  56
  57         def unlink(self, path):
  58                 return os.unlink(path)
  59
  60         def open(self, path, mode = 'r'):
  61                 stream = file(path, mode)
  62                 streams[id(stream)] = stream
  63                 return id(stream)
  64
  65         def close(self, stream):
  66                 streams[stream].close()
  67                 del streams[stream]
  68
  69         def read(self, stream, length = 0):
  70                 return streams[stream].read(length)
  71
  72         def write(self, stream, data):
  73                 return streams[stream].write(data)
  74
  75         def rename(self, old, new):
  76                 return os.rename(old, new)
  77
  78         def chmod(self, path, mode):
  79                 return os.chmod(path, mode)
  80
  81 if __name__ == '__main__':
  82         from select import select
  83
  84         to_parent, from_parent = map(int, sys.argv[1:])
  85
  86         sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(sys.argv[0]))))
  87
  88         slave_proxy = SuSlave(to_parent, from_parent, Slave())
  89
  90         while read_watches or write_watches:
  91                 readable, writable = select(read_watches, write_watches, [])[:2]
  92                 for w in readable:
  93                         if not w.ready():
  94                                 read_watches.remove(w)
  95                 for w in writable:
  96                         if not w.ready():
  97                                 write_watches.remove(w)