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/*
* (C) 2016 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
* Authors: Neels Hofmeyr <nhofmeyr@sysmocom.de>
* All Rights Reserved
*
* SPDX-License-Identifier: GPL-2.0+
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
/*! \addtogroup timer
* @{
* \file timer_gettimeofday.c
* Overriding Time: osmo_gettimeofday()
* - Useful to write and reproduce tests that depend on specific time
* factors. This API allows to fake the timeval provided by `gettimeofday()`
* by using a small shim osmo_gettimeofday().
* - If the clock override is disabled (default) for a given clock,
* osmo_gettimeofday() will do the same as regular `gettimeofday()`.
* - If you want osmo_gettimeofday() to provide a specific time, you must
* enable time override by setting the global variable
* osmo_gettimeofday_override (`osmo_gettimeofday_override = true`), then
* set the global struct timeval osmo_gettimeofday_override_time wih the
* desired value. Next time osmo_gettimeofday() is called, it will return
* the values previously set.
* - A helper osmo_gettimeofday_override_add() is provided to easily
* increment osmo_gettimeofday_override_time with a specific amount of
* time.
*/
#include <stdbool.h>
#include <sys/time.h>
#include <osmocom/core/timer_compat.h>
bool osmo_gettimeofday_override = false;
struct timeval osmo_gettimeofday_override_time = { 23, 424242 };
/*! shim around gettimeofday to be able to set the time manually.
* To override, set osmo_gettimeofday_override == true and set the desired
* current time in osmo_gettimeofday_override_time.
*
* N. B: gettimeofday() is affected by discontinuous jumps in the system time
* (e.g., if the system administrator manually changes the system time).
* Hence this should NEVER be used for elapsed time computation.
* Instead, osmo_clock_gettime() with CLOCK_MONOTONIC should be used for that.
*/
int osmo_gettimeofday(struct timeval *tv, struct timezone *tz)
{
if (osmo_gettimeofday_override) {
*tv = osmo_gettimeofday_override_time;
return 0;
}
return gettimeofday(tv, tz);
}
/*! convenience function to advance the fake time.
* Add the given values to osmo_gettimeofday_override_time. */
void osmo_gettimeofday_override_add(time_t secs, suseconds_t usecs)
{
struct timeval val = { secs, usecs };
timeradd(&osmo_gettimeofday_override_time, &val,
&osmo_gettimeofday_override_time);
}
/*! @} */
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