From 87fade88bd8471d0459a306255403e854122120e Mon Sep 17 00:00:00 2001 From: Pau Espin Pedrol Date: Mon, 26 Feb 2018 19:42:22 +0100 Subject: timer: Introduce osmo_clock_gettime to override clock_gettime Change-Id: I5bebc6e01fc9d238065bc2517058f0ba85620349 --- src/timer_clockgettime.c | 138 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 138 insertions(+) create mode 100644 src/timer_clockgettime.c (limited to 'src/timer_clockgettime.c') diff --git a/src/timer_clockgettime.c b/src/timer_clockgettime.c new file mode 100644 index 00000000..8d9760c5 --- /dev/null +++ b/src/timer_clockgettime.c @@ -0,0 +1,138 @@ +/* + * (C) 2016 by sysmocom s.f.m.c. GmbH + * All Rights Reserved + * + * Authors: Pau Espin Pedrol + * + * 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_clockgettime.c + * Overriding Time: osmo_clock_gettime() + * - Useful to write and reproduce tests that depend on specific time + * factors. This API allows to fake the timespec provided by `clock_gettime()` + * by using a small shim osmo_clock_gettime(). + * - Choose the clock you want to override, for instance CLOCK_MONOTONIC. + * - If the clock override is disabled (default) for a given clock, + * osmo_clock_gettime() will do the same as regular `clock_gettime()`. + * - If you want osmo_clock_gettime() to provide a specific time, you must + * enable time override with osmo_clock_override_enable(), + * then set a pointer to the timespec storing the fake time for that + * specific clock (`struct timespec *ts = + * osmo_clock_override_gettimespec()`) and set it as + * desired. Next time osmo_clock_gettime() is called, it will return the + * values previously set through the ts pointer. + * - A helper osmo_clock_override_add() is provided to increment a given + * overriden clock with a specific amount of time. + */ + +/*! \file timer_clockgettime.c + */ + +#include +#include +#include +#include + +#include + +/*! An internal structure to handle overriden time for each clock type. */ +struct fakeclock { + bool override; + struct timespec time; +}; + +static struct fakeclock realtime; +static struct fakeclock realtime_coarse; +static struct fakeclock mono; +static struct fakeclock mono_coarse; +static struct fakeclock mono_raw; +static struct fakeclock boottime; +static struct fakeclock boottime; +static struct fakeclock proc_cputime_id; +static struct fakeclock th_cputime_id; + +static struct fakeclock* clkid_to_fakeclock(clockid_t clk_id) +{ + switch(clk_id) { + case CLOCK_REALTIME: + return &realtime; + case CLOCK_REALTIME_COARSE: + return &realtime_coarse; + case CLOCK_MONOTONIC: + return &mono; + case CLOCK_MONOTONIC_COARSE: + return &mono_coarse; + case CLOCK_MONOTONIC_RAW: + return &mono_raw; + case CLOCK_BOOTTIME: + return &boottime; + case CLOCK_PROCESS_CPUTIME_ID: + return &proc_cputime_id; + case CLOCK_THREAD_CPUTIME_ID: + return &th_cputime_id; + default: + return NULL; + } +} + +/*! Shim around clock_gettime to be able to set the time manually. + * + * To override, use osmo_clock_override_enable and set the desired + * current time with osmo_clock_gettimespec. */ +int osmo_clock_gettime(clockid_t clk_id, struct timespec *tp) +{ + struct fakeclock* c = clkid_to_fakeclock(clk_id); + if (!c || !c->override) + return clock_gettime(clk_id, tp); + + *tp = c->time; + return 0; +} + +/*! Convenience function to enable or disable a specific clock fake time. + */ +void osmo_clock_override_enable(clockid_t clk_id, bool enable) +{ + struct fakeclock* c = clkid_to_fakeclock(clk_id); + if (c) + c->override = enable; +} + +/*! Convenience function to return a pointer to the timespec handling the + * fake time for clock clk_id. */ +struct timespec *osmo_clock_override_gettimespec(clockid_t clk_id) +{ + struct fakeclock* c = clkid_to_fakeclock(clk_id); + if (c) + return &c->time; + return NULL; +} + +/*! Convenience function to advance the fake time. + * + * Adds the given values to the clock time. */ +void osmo_clock_override_add(clockid_t clk_id, time_t secs, long nsecs) +{ + struct timespec val = { secs, nsecs }; + struct fakeclock* c = clkid_to_fakeclock(clk_id); + if (c) + timespecadd(&c->time, &val, &c->time); +} + +/*! @} */ -- cgit v1.2.3