Runtime : force using monotonic time in Timer (threading). Prevent watchdog to trigger when changing system time.
authorEdouard Tisserant
Thu, 20 Jan 2022 11:39:05 +0100
changeset 3420 da8cceaa247d
parent 3419 76995a304fe0
child 3421 70ef15fca028
Runtime : force using monotonic time in Timer (threading). Prevent watchdog to trigger when changing system time.
Beremiz_service.py
runtime/monotonic_time.py
--- a/Beremiz_service.py	Thu Jan 20 11:16:52 2022 +0100
+++ b/Beremiz_service.py	Thu Jan 20 11:39:05 2022 +0100
@@ -32,6 +32,7 @@
 import threading
 import shlex
 import traceback
+import threading
 from threading import Thread, Semaphore, Lock, currentThread
 from builtins import str as text
 from past.builtins import execfile
@@ -46,6 +47,14 @@
 from runtime.Stunnel import ensurePSK
 import util.paths as paths
 
+# In case system time is ajusted, it is better to use
+# monotonic timers for timers and other timeout based operations.
+# hot-patch threading module to force using monitonic time for all 
+# Thread/Timer/Event/Condition
+
+from runtime.monotonic_time import monotonic
+threading._time = monotonic
+
 try:
     from runtime.spawn_subprocess import Popen
 except ImportError:
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/runtime/monotonic_time.py	Thu Jan 20 11:39:05 2022 +0100
@@ -0,0 +1,159 @@
+# vi: set ft=python sw=4 ts=4 et:
+
+'''monotonic time for Python 2 and 3, on Linux, FreeBSD, Mac OS X, and Windows.
+
+Copyright 2010, 2011, 2017 Gavin Beatty <gavinbeatty@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+'''
+
+from __future__ import print_function
+from __future__ import unicode_literals
+
+__author__ = 'Gavin Beatty <gavinbeatty@gmail.com>'
+__version__ = '2.1.0.dev0'
+__date__ = '2017-05-28'
+__all__ = ['monotonic']
+
+import contextlib
+import ctypes
+import errno
+import os
+import platform
+import sys
+import time
+
+_machine64 = (platform.machine(), sys.maxsize > 2**32)
+
+
+class _NS():
+    pass
+
+
+class _mach_timespec(ctypes.Structure):
+    _fields_ = [('tv_sec', ctypes.c_uint), ('tv_nsec', ctypes.c_int)]
+
+
+class _posix_timespec(ctypes.Structure):
+    _fields_ = [('tv_sec', ctypes.c_long), ('tv_nsec', ctypes.c_long)]
+
+
+def _timespec_to_seconds(ts):
+    return float(ts.tv_sec) + float(ts.tv_nsec) * 1e-9
+
+
+def _get_ctypes_libmacho_macho_functions():
+    libmacho = ctypes.CDLL('/usr/lib/system/libmacho.dylib', use_errno=True)
+    macho = _NS()
+    macho.get_host = libmacho.mach_host_self
+    macho.get_host.argtypes = []
+    macho.get_host.restype = ctypes.c_uint
+    macho.get_clock = libmacho.host_get_clock_service
+    macho.get_clock.argtypes = [ctypes.c_uint,
+                                ctypes.c_int,
+                                ctypes.POINTER(ctypes.c_uint)
+                                ]
+    macho.get_time = libmacho.clock_get_time
+    macho.get_time.argtypes = [ctypes.c_uint, ctypes.POINTER(_mach_timespec)]
+    macho.deallocate = libmacho.mach_port_deallocate
+    macho.deallocate.argtypes = [ctypes.c_uint, ctypes.c_uint]
+    return libmacho, macho
+
+
+def _get_ctypes_clock_gettime(library):
+    clock_gettime = ctypes.CDLL(library, use_errno=True).clock_gettime
+    clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(_posix_timespec)]
+    return clock_gettime
+
+
+def _call_ctypes_clock_gettime(clock_gettime, clockid):
+    timespec = _posix_timespec()
+    ret = clock_gettime(clockid, ctypes.pointer(timespec))
+    if int(ret) != 0:
+        errno_ = ctypes.get_errno()
+        raise OSError(errno_, os.strerror(errno_))
+    return timespec
+
+
+_py_monotonic = getattr(time, 'monotonic', None)
+if _py_monotonic is not None:
+    monotonic = _py_monotonic
+elif sys.platform.startswith('linux'):
+    _clock_gettime = _get_ctypes_clock_gettime('librt.so.1')
+
+    def monotonic():
+        clockid = ctypes.c_int(1)
+        timespec = _call_ctypes_clock_gettime(_clock_gettime, clockid)
+        return _timespec_to_seconds(timespec)
+elif sys.platform.startswith('freebsd'):
+    _clock_gettime = _get_ctypes_clock_gettime('libc.so')
+
+    def monotonic():
+        clockid = ctypes.c_int(4)
+        timespec = _call_ctypes_clock_gettime(_clock_gettime, clockid)
+        return _timespec_to_seconds(timespec)
+elif sys.platform.startswith('darwin') and _machine64 == ('x86_64', True):
+    _libmacho, _macho = _get_ctypes_libmacho_macho_functions()
+
+    @contextlib.contextmanager
+    def _deallocate(task, port):
+        try:
+            yield
+        finally:
+            if int(_macho.deallocate(task, port)) == 0:
+                return
+            errno_ = ctypes.get_errno()
+            raise OSError(errno_, os.strerror(errno_))
+
+    def monotonic():
+        task = ctypes.c_uint.in_dll(_libmacho, 'mach_task_self_')
+        host = _macho.get_host()
+        with _deallocate(task, host):
+            clock = ctypes.c_uint(0)
+            clockid = ctypes.c_int(0)
+            ret = _macho.get_clock(host, clockid, ctypes.pointer(clock))
+            if int(ret) != 0:
+                errno_ = ctypes.get_errno()
+                raise OSError(errno_, os.strerror(errno_))
+            with _deallocate(task, clock):
+                timespec = _mach_timespec()
+                ret = _macho.get_time(clock, ctypes.pointer(timespec))
+                if int(ret) != 0:
+                    errno_ = ctypes.get_errno()
+                    raise OSError(errno_, os.strerror(errno_))
+                return _timespec_to_seconds(timespec)
+elif sys.platform.startswith('win32'):
+    _GetTickCount = getattr(ctypes.windll.kernel32, 'GetTickCount64', None)
+
+    if _GetTickCount is not None:
+        _GetTickCount.restype = ctypes.c_uint64
+    else:
+        _GetTickCount = ctypes.windll.kernel32.GetTickCount
+        _GetTickCount.restype = ctypes.c_uint32
+
+    def monotonic():
+        return float(_GetTickCount()) * 1e-3
+else:
+    def monotonic():
+        msg = 'monotonic not supported on your platform'
+        raise OSError(errno.ENOSYS, msg)
+
+
+if __name__ == '__main__':
+    print(monotonic())