Use ctypes in subprocess for bug #448858.

Isolate ctypes usage in a subprocess, in order to avoid potential
problems with stale cached libraries as described in bug #448858,
comment #14 (also see http://bugs.python.org/issue14597).

2 files changed, 67 insertions, 33 deletions

diff --git a/pym/portage/dbapi/_SyncfsProcess.py b/pym/portage/dbapi/_SyncfsProcess.py
new file mode 100644
index 000000000..7518214ec
--- /dev/null
+++ b/pym/portage/dbapi/_SyncfsProcess.py
@@ -0,0 +1,53 @@
+# Copyright 2012 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+from portage import os
+from portage.util._ctypes import find_library, LoadLibrary
+from portage.util._async.ForkProcess import ForkProcess
+
+class SyncfsProcess(ForkProcess):
+	"""
+	Isolate ctypes usage in a subprocess, in order to avoid
+	potential problems with stale cached libraries as
+	described in bug #448858, comment #14 (also see
+	http://bugs.python.org/issue14597).
+	"""
+
+	__slots__ = ('paths',)
+
+	@staticmethod
+	def _get_syncfs():
+
+		filename = find_library("c")
+		if filename is not None:
+			library = LoadLibrary(filename)
+			if library is not None:
+				try:
+					return library.syncfs
+				except AttributeError:
+					pass
+
+		return None
+
+	def _run(self):
+
+		syncfs_failed = False
+		syncfs = self._get_syncfs()
+
+		if syncfs is not None:
+			for path in self.paths:
+				try:
+					fd = os.open(path, os.O_RDONLY)
+				except OSError:
+					pass
+				else:
+					try:
+						if syncfs(fd) != 0:
+							# Happens with PyPy (bug #446610)
+							syncfs_failed = True
+					finally:
+						os.close(fd)
+
+		if syncfs is None or syncfs_failed:
+			return 1
+		return os.EX_OK
diff --git a/pym/portage/dbapi/vartree.py b/pym/portage/dbapi/vartree.py
index 840e796f1..7a930e553 100644
--- a/pym/portage/dbapi/vartree.py
+++ b/pym/portage/dbapi/vartree.py
@@ -11,6 +11,7 @@ portage.proxy.lazyimport.lazyimport(globals(),
 	'portage.data:portage_gid,portage_uid,secpass',
 	'portage.dbapi.dep_expand:dep_expand',
 	'portage.dbapi._MergeProcess:MergeProcess',
+	'portage.dbapi._SyncfsProcess:SyncfsProcess',
 	'portage.dep:dep_getkey,isjustname,isvalidatom,match_from_list,' + \
 	 	'use_reduce,_get_slot_re,_slot_separator,_repo_separator',
 	'portage.eapi:_get_eapi_attrs',
@@ -29,7 +30,6 @@ portage.proxy.lazyimport.lazyimport(globals(),
 	'portage.util.env_update:env_update',
 	'portage.util.listdir:dircache,listdir',
 	'portage.util.movefile:movefile',
-	'portage.util._ctypes:find_library,LoadLibrary',
 	'portage.util._dyn_libs.PreservedLibsRegistry:PreservedLibsRegistry',
 	'portage.util._dyn_libs.LinkageMapELF:LinkageMapELF@LinkageMap',
 	'portage.util._async.SchedulerInterface:SchedulerInterface',
@@ -4731,28 +4731,22 @@ class dblink(object):
 			"merge-sync" not in self.settings.features:
 			return
 
-		syncfs_failed = False
-		syncfs = _get_syncfs()
+		returncode = None
+		if platform.system() == "Linux":
 
-		if syncfs is not None:
+			paths = []
 			for path in self._device_path_map.values():
-				if path is False:
-					continue
-				try:
-					fd = os.open(path, os.O_RDONLY)
-				except OSError:
-					pass
-				else:
-					try:
-						if syncfs(fd) != 0:
-							# Happens with PyPy (bug #446610)
-							syncfs_failed = True
-					except OSError:
-						pass
-					finally:
-						os.close(fd)
+				if path is not False:
+					paths.append(path)
+			paths = tuple(paths)
+
+			proc = SyncfsProcess(paths=paths,
+				scheduler=(self._scheduler or
+				SchedulerInterface(EventLoop(main=False))))
+			proc.start()
+			returncode = proc.wait()
 
-		if syncfs is None or syncfs_failed:
+		if returncode is None or returncode != os.EX_OK:
 			try:
 				proc = subprocess.Popen(["sync"])
 			except EnvironmentError:
@@ -4938,19 +4932,6 @@ class dblink(object):
 		finally:
 			self.unlockdb()
 
-def _get_syncfs():
-	if platform.system() == "Linux":
-		filename = find_library("c")
-		if filename is not None:
-			library = LoadLibrary(filename)
-			if library is not None:
-				try:
-					return library.syncfs
-				except AttributeError:
-					pass
-
-	return None
-
 def merge(mycat, mypkg, pkgloc, infloc,
 	myroot=None, settings=None, myebuild=None,
 	mytree=None, mydbapi=None, vartree=None, prev_mtimes=None, blockers=None,