pym/_emerge/FifoIpcDaemon.py

   1 # Copyright 2010-2013 Gentoo Foundation
   2 # Distributed under the terms of the GNU General Public License v2
   3
   4 import sys
   5
   6 try:
   7         import fcntl
   8 except ImportError:
   9         #  http://bugs.jython.org/issue1074
  10         fcntl = None
  11
  12 from portage import os
  13 from _emerge.AbstractPollTask import AbstractPollTask
  14 from portage.cache.mappings import slot_dict_class
  15
  16 class FifoIpcDaemon(AbstractPollTask):
  17
  18         __slots__ = ("input_fifo", "output_fifo",) + \
  19                 ("_files", "_reg_id",)
  20
  21         _file_names = ("pipe_in",)
  22         _files_dict = slot_dict_class(_file_names, prefix="")
  23
  24         def _start(self):
  25                 self._files = self._files_dict()
  26
  27                 # File streams are in unbuffered mode since we do atomic
  28                 # read and write of whole pickles.
  29                 self._files.pipe_in = \
  30                         os.open(self.input_fifo, os.O_RDONLY|os.O_NONBLOCK)
  31
  32                 # FD_CLOEXEC is enabled by default in Python >=3.4.
  33                 if sys.hexversion < 0x3040000 and fcntl is not None:
  34                         try:
  35                                 fcntl.FD_CLOEXEC
  36                         except AttributeError:
  37                                 pass
  38                         else:
  39                                 fcntl.fcntl(self._files.pipe_in, fcntl.F_SETFD,
  40                                         fcntl.fcntl(self._files.pipe_in,
  41                                                 fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
  42
  43                 self._reg_id = self.scheduler.io_add_watch(
  44                         self._files.pipe_in,
  45                         self._registered_events, self._input_handler)
  46
  47                 self._registered = True
  48
  49         def _reopen_input(self):
  50                 """
  51                 Re-open the input stream, in order to suppress
  52                 POLLHUP events (bug #339976).
  53                 """
  54                 self.scheduler.source_remove(self._reg_id)
  55                 os.close(self._files.pipe_in)
  56                 self._files.pipe_in = \
  57                         os.open(self.input_fifo, os.O_RDONLY|os.O_NONBLOCK)
  58
  59                 # FD_CLOEXEC is enabled by default in Python >=3.4.
  60                 if sys.hexversion < 0x3040000 and fcntl is not None:
  61                         try:
  62                                 fcntl.FD_CLOEXEC
  63                         except AttributeError:
  64                                 pass
  65                         else:
  66                                 fcntl.fcntl(self._files.pipe_in, fcntl.F_SETFD,
  67                                         fcntl.fcntl(self._files.pipe_in,
  68                                                 fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
  69
  70                 self._reg_id = self.scheduler.io_add_watch(
  71                         self._files.pipe_in,
  72                         self._registered_events, self._input_handler)
  73
  74         def isAlive(self):
  75                 return self._registered
  76
  77         def _cancel(self):
  78                 if self.returncode is None:
  79                         self.returncode = 1
  80                 self._unregister()
  81                 # notify exit listeners
  82                 self.wait()
  83
  84         def _wait(self):
  85                 if self.returncode is not None:
  86                         return self.returncode
  87                 self._wait_loop()
  88                 if self.returncode is None:
  89                         self.returncode = os.EX_OK
  90                 return self.returncode
  91
  92         def _input_handler(self, fd, event):
  93                 raise NotImplementedError(self)
  94
  95         def _unregister(self):
  96                 """
  97                 Unregister from the scheduler and close open files.
  98                 """
  99
 100                 self._registered = False
 101
 102                 if self._reg_id is not None:
 103                         self.scheduler.source_remove(self._reg_id)
 104                         self._reg_id = None
 105
 106                 if self._files is not None:
 107                         for f in self._files.values():
 108                                 os.close(f)
 109                         self._files = None