1 files changed, 108 insertions, 0 deletions
diff --git a/pym/_emerge/FifoIpcDaemon.py b/pym/_emerge/FifoIpcDaemon.py
new file mode 100644
index 000000000..16bc786ae
--- /dev/null
+++ b/pym/_emerge/FifoIpcDaemon.py
@@ -0,0 +1,108 @@
+# Copyright 2010 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+import array
+import pickle
+from portage import os
+from _emerge.AbstractPollTask import AbstractPollTask
+from _emerge.PollConstants import PollConstants
+from portage.cache.mappings import slot_dict_class
+
+class FifoIpcDaemon(AbstractPollTask):
+
+	"""
+    This class serves as an IPC daemon, which ebuild processes can use
+    to communicate with portage's main python process.
+
+    Here are a few possible uses:
+
+    1) Robust subshell/subprocess die support. This allows the ebuild
+       environment to reliably die without having to rely on signal IPC.
+
+    2) Delegation of portageq calls to the main python process, eliminating
+       performance and userpriv permission issues.
+
+    3) Reliable ebuild termination in cases when the ebuild has accidentally
+       left orphan processes running in the backgraound (as in bug 278895).
+	"""
+
+	__slots__ = ("input_fifo", "output_fifo",) + \
+		("_files", "_reg_id",)
+
+	_file_names = ("pipe_in",)
+	_files_dict = slot_dict_class(_file_names, prefix="")
+
+	def _start(self):
+		self._files = self._files_dict()
+		input_fd = os.open(self.input_fifo, os.O_RDONLY|os.O_NONBLOCK)
+		self._files.pipe_in = os.fdopen(input_fd, 'rb')
+
+		self._reg_id = self.scheduler.register(
+			self._files.pipe_in.fileno(),
+			self._registered_events, self._input_handler)
+
+		self._registered = True
+
+	def isAlive(self):
+		return self._registered
+
+	def cancel(self):
+		if self.returncode is None:
+			self.returncode = 1
+			self.cancelled = True
+		self._unregister()
+		self.wait()
+
+	def _wait(self):
+		if self.returncode is not None:
+			return self.returncode
+
+		if self._registered:
+			self.scheduler.schedule(self._reg_id)
+			self._unregister()
+
+		if self.returncode is None:
+			self.returncode = os.EX_OK
+
+		return self.returncode
+
+	def _input_handler(self, fd, event):
+
+		if event & PollConstants.POLLIN:
+
+			buf = array.array('B')
+			try:
+				buf.fromfile(self._files.pipe_in, self._bufsize)
+			except (EOFError, IOError):
+				pass
+
+			if buf:
+				obj = pickle.loads(buf.tostring())
+				if isinstance(obj, list) and \
+					obj and \
+					obj[0] == 'exit':
+					output_fd = os.open(self.output_fifo, os.O_WRONLY|os.O_NONBLOCK)
+					output_file = os.fdopen(output_fd, 'wb')
+					pickle.dump('OK', output_file)
+					output_file.close()
+					self._unregister()
+					self.wait()
+
+		self._unregister_if_appropriate(event)
+		return self._registered
+
+	def _unregister(self):
+		"""
+		Unregister from the scheduler and close open files.
+		"""
+
+		self._registered = False
+
+		if self._reg_id is not None:
+			self.scheduler.unregister(self._reg_id)
+			self._reg_id = None
+
+		if self._files is not None:
+			for f in self._files.values():
+				f.close()
+			self._files = None