mirror of https://gerrit.osmocom.org/libosmocore
76 lines
2.9 KiB
C
76 lines
2.9 KiB
C
/*
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* (C) 2016 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
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* Authors: Neels Hofmeyr <nhofmeyr@sysmocom.de>
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* All Rights Reserved
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*
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* SPDX-License-Identifier: GPL-2.0+
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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/*! \addtogroup timer
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* @{
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* \file timer_gettimeofday.c
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* Overriding Time: osmo_gettimeofday()
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* - Useful to write and reproduce tests that depend on specific time
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* factors. This API allows to fake the timeval provided by `gettimeofday()`
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* by using a small shim osmo_gettimeofday().
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* - If the clock override is disabled (default) for a given clock,
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* osmo_gettimeofday() will do the same as regular `gettimeofday()`.
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* - If you want osmo_gettimeofday() to provide a specific time, you must
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* enable time override by setting the global variable
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* osmo_gettimeofday_override (`osmo_gettimeofday_override = true`), then
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* set the global struct timeval osmo_gettimeofday_override_time wih the
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* desired value. Next time osmo_gettimeofday() is called, it will return
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* the values previously set.
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* - A helper osmo_gettimeofday_override_add() is provided to easily
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* increment osmo_gettimeofday_override_time with a specific amount of
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* time.
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*/
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#include <stdbool.h>
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#include <sys/time.h>
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#include <osmocom/core/timer_compat.h>
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bool osmo_gettimeofday_override = false;
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struct timeval osmo_gettimeofday_override_time = { 23, 424242 };
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/*! shim around gettimeofday to be able to set the time manually.
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* To override, set osmo_gettimeofday_override == true and set the desired
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* current time in osmo_gettimeofday_override_time.
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*
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* N. B: gettimeofday() is affected by discontinuous jumps in the system time
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* (e.g., if the system administrator manually changes the system time).
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* Hence this should NEVER be used for elapsed time computation.
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* Instead, osmo_clock_gettime() with CLOCK_MONOTONIC should be used for that.
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*/
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int osmo_gettimeofday(struct timeval *tv, struct timezone *tz)
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{
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if (osmo_gettimeofday_override) {
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*tv = osmo_gettimeofday_override_time;
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return 0;
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}
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return gettimeofday(tv, tz);
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}
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/*! convenience function to advance the fake time.
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* Add the given values to osmo_gettimeofday_override_time. */
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void osmo_gettimeofday_override_add(time_t secs, suseconds_t usecs)
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{
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struct timeval val = { secs, usecs };
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timeradd(&osmo_gettimeofday_override_time, &val,
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&osmo_gettimeofday_override_time);
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}
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/*! @} */
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