From 142c1ad0891b3d97dfae4f0ae376617189905a17 Mon Sep 17 00:00:00 2001
From: Guido Trotter <ultrotter@google.com>
Date: Wed, 19 Oct 2011 18:28:42 +0100
Subject: [PATCH] Revert "utils.cfunc: Cleanup, more flexibility"
We discussed that this is not needed right now, and it breaks existing
functionality and unittests.
This reverts commit 6915fe26da8dce41fc967d761f005390aa956161.
Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>
---
Makefile.am | 2 +-
lib/utils/cfunc.py | 73 +++++++------------
...test.py => ganeti.utils.cfunc_unittest.py} | 4 +-
3 files changed, 32 insertions(+), 47 deletions(-)
rename test/{ganeti.utils.cfunc.mlockall_unittest.py => ganeti.utils.cfunc_unittest.py} (97%)
diff --git a/Makefile.am b/Makefile.am
index 5031a5303..2a513f15f 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -724,7 +724,7 @@ python_tests = \
test/ganeti.tools.ensure_dirs_unittest.py \
test/ganeti.uidpool_unittest.py \
test/ganeti.utils.algo_unittest.py \
- test/ganeti.utils.cfunc.mlockall_unittest.py \
+ test/ganeti.utils.cfunc_unittest.py \
test/ganeti.utils.filelock_unittest.py \
test/ganeti.utils.hash_unittest.py \
test/ganeti.utils.io_unittest.py \
diff --git a/lib/utils/cfunc.py b/lib/utils/cfunc.py
index a1b3af49b..ea14d6848 100644
--- a/lib/utils/cfunc.py
+++ b/lib/utils/cfunc.py
@@ -34,61 +34,44 @@ except ImportError:
ctypes = None
-# Flags for mlockall(2) (from bits/mman.h)
+# Flags for mlockall() (from bits/mman.h)
_MCL_CURRENT = 1
_MCL_FUTURE = 2
-class _FuncWrapper:
- def __init__(self, ct):
- """Initializes this class.
-
- """
- # Make use of a dlopen(3) feature whereby giving a NULL handle returns the
- # main program. Functions from all previously loaded libraries can then be
- # used.
- mainprog = ct.CDLL(None)
-
- # The ctypes module before Python 2.6 does not have built-in functionality
- # to access the global errno global (which, depending on the libc and build
- # options, is per-thread), where function error codes are stored. Use GNU
- # libc's way to retrieve errno(3) instead.
- try:
- errno_loc = getattr(mainprog, "__errno_location")
- except AttributeError, err:
- logging.debug("Unable to find errno location: %s", err)
- errno_fn = None
- else:
- errno_loc.restype = ct.POINTER(ct.c_int)
- errno_fn = lambda: errno_loc().contents.value
-
- self.errno_fn = errno_fn
-
- # Try to get mlockall(2)
- self.mlockall_fn = getattr(mainprog, "mlockall", None)
-
-
def Mlockall(_ctypes=ctypes):
"""Lock current process' virtual address space into RAM.
- This is equivalent to the C call C{mlockall(MCL_CURRENT | MCL_FUTURE)}. See
- mlockall(2) for more details. This function requires the C{ctypes} module.
+ This is equivalent to the C call mlockall(MCL_CURRENT|MCL_FUTURE),
+ see mlock(2) for more details. This function requires ctypes module.
- @raises errors.NoCtypesError: If the C{ctypes} module is not found
+ @raises errors.NoCtypesError: if ctypes module is not found
"""
if _ctypes is None:
raise errors.NoCtypesError()
- funcs = _FuncWrapper(_ctypes)
-
- if funcs.mlockall_fn is None:
- logging.debug("libc doesn't support mlockall(2)")
- else:
- if funcs.mlockall_fn(_MCL_CURRENT | _MCL_FUTURE) == 0:
- logging.debug("Memory lock set")
- return True
-
- logging.error("Cannot set memory lock: %s", os.strerror(funcs.errno_fn()))
-
- return False
+ try:
+ libc = _ctypes.cdll.LoadLibrary("libc.so.6")
+ except EnvironmentError, err:
+ logging.error("Failure trying to load libc: %s", err)
+ libc = None
+ if libc is None:
+ logging.error("Cannot set memory lock, ctypes cannot load libc")
+ return
+
+ # Some older version of the ctypes module don't have built-in functionality
+ # to access the errno global variable, where function error codes are stored.
+ # By declaring this variable as a pointer to an integer we can then access
+ # its value correctly, should the mlockall call fail, in order to see what
+ # the actual error code was.
+ # pylint: disable=W0212
+ libc.__errno_location.restype = _ctypes.POINTER(_ctypes.c_int)
+
+ if libc.mlockall(_MCL_CURRENT | _MCL_FUTURE):
+ # pylint: disable=W0212
+ logging.error("Cannot set memory lock: %s",
+ os.strerror(libc.__errno_location().contents.value))
+ return
+
+ logging.debug("Memory lock set")
diff --git a/test/ganeti.utils.cfunc.mlockall_unittest.py b/test/ganeti.utils.cfunc_unittest.py
similarity index 97%
rename from test/ganeti.utils.cfunc.mlockall_unittest.py
rename to test/ganeti.utils.cfunc_unittest.py
index bafa71c8d..8c5c7469b 100755
--- a/test/ganeti.utils.cfunc.mlockall_unittest.py
+++ b/test/ganeti.utils.cfunc_unittest.py
@@ -41,15 +41,17 @@ class TestMlockallWithCtypes(unittest.TestCase):
"""Whether Mlockall() works if ctypes is present.
"""
+
def test(self):
if utils.ctypes:
- self.assertTrue(utils.Mlockall())
+ utils.Mlockall()
class TestMlockallWithNoCtypes(unittest.TestCase):
"""Whether Mlockall() raises an error if ctypes is not present.
"""
+
def test(self):
self.assertRaises(errors.NoCtypesError, utils.Mlockall, _ctypes=None)
--
GitLab