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50a1a1d2cc
This patch also checks the system platform as clock_gettime could exist on different platforms but with different values of CLOCK_MONOTONIC and different definitions of 'struct timespec'. In this case, the system call would be expected to catch the error, which is dangerous. This patch ensures Linux, NetBSD and FreeBSD platforms use clock_gettime with their corresponding correct values and definitions. All other platforms use time.time(). Signed-off-by: Ryan Wilson <wryan@nicira.com> Acked-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
79 lines
2.4 KiB
Python
79 lines
2.4 KiB
Python
# Copyright (c) 2009, 2010 Nicira, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at:
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import sys
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import time
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try:
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import ctypes
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LIBRT = 'librt.so.1'
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clock_gettime_name = 'clock_gettime'
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if sys.platform.startswith("linux"):
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CLOCK_MONOTONIC = 1
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time_t = ctypes.c_long
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elif sys.platform.startswith("netbsd"):
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# NetBSD uses function renaming for ABI versioning. While the proper
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# way to get the appropriate version is of course "#include <time.h>",
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# it is difficult with ctypes. The following is appropriate for
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# recent versions of NetBSD, including NetBSD-6.
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LIBRT = 'libc.so.12'
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clock_gettime_name = '__clock_gettime50'
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CLOCK_MONOTONIC = 3
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time_t = ctypes.c_int64
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elif sys.platform.startswith("freebsd"):
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CLOCK_MONOTONIC = 4
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time_t = ctypes.c_int64
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else:
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raise Exception
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class timespec(ctypes.Structure):
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_fields_ = [
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('tv_sec', time_t),
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('tv_nsec', ctypes.c_long),
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]
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librt = ctypes.CDLL(LIBRT)
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clock_gettime = getattr(librt, clock_gettime_name)
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clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(timespec)]
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except:
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# Librt shared library could not be loaded
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librt = None
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def monotonic():
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if not librt:
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return time.time()
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t = timespec()
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if clock_gettime(CLOCK_MONOTONIC, ctypes.pointer(t)) == 0:
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return t.tv_sec + t.tv_nsec * 1e-9
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# Kernel does not support CLOCK_MONOTONIC
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return time.time()
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# Use time.monotonic() if Python version >= 3.3
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if not hasattr(time, 'monotonic'):
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time.monotonic = monotonic
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def msec():
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""" Returns the system's monotonic time if possible, otherwise returns the
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current time as the amount of time since the epoch, in milliseconds, as a
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float."""
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return time.monotonic() * 1000.0
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def postfork():
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# Just a stub for now
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pass
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