2 files changed, 148 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
diff --git a/pym/portage/tests/ebuild/test_ipc_daemon.py b/pym/portage/tests/ebuild/test_ipc_daemon.py
new file mode 100644
index 000000000..c3d0ae2e4
--- /dev/null
+++ b/pym/portage/tests/ebuild/test_ipc_daemon.py
@@ -0,0 +1,40 @@
+# Copyright 2010 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+import shutil
+import tempfile
+from portage import os
+from portage.tests import TestCase
+from portage.const import PORTAGE_BIN_PATH
+from portage.const import PORTAGE_PYM_PATH
+from portage.const import BASH_BINARY
+from _emerge.SpawnProcess import SpawnProcess
+from _emerge.FifoIpcDaemon import FifoIpcDaemon
+from _emerge.TaskScheduler import TaskScheduler
+
+class IpcDaemonTestCase(TestCase):
+
+	def testIpcDaemon(self):
+		tmpdir = tempfile.mkdtemp()
+		try:
+			env = {}
+			env['PORTAGE_BIN_PATH'] = PORTAGE_BIN_PATH
+			env['PORTAGE_PYM_PATH'] = PORTAGE_PYM_PATH
+			env['PORTAGE_BUILDDIR'] = tmpdir
+			input_fifo = os.path.join(tmpdir, '.ipc_in')
+			output_fifo = os.path.join(tmpdir, '.ipc_out')
+			os.mkfifo(input_fifo)
+			os.mkfifo(output_fifo)
+			task_scheduler = TaskScheduler(max_jobs=2)
+			daemon = FifoIpcDaemon(input_fifo=input_fifo,
+				output_fifo=output_fifo,
+				scheduler=task_scheduler.sched_iface)
+			proc = SpawnProcess(
+				args=[BASH_BINARY, "-c", '"$PORTAGE_BIN_PATH"/ebuild-ipc exit 0'],
+				env=env, scheduler=task_scheduler.sched_iface)
+			task_scheduler.add(daemon)
+			task_scheduler.add(proc)
+			task_scheduler.run()
+			self.assertEqual(proc.returncode, os.EX_OK)
+		finally:
+			shutil.rmtree(tmpdir)