| /* |
| * (C) 2008,2009 by Holger Hans Peter Freyther <zecke@selfish.org> |
| * (C) 2011 by Harald Welte <laforge@gnumonks.org> |
| * All Rights Reserved |
| * |
| * Authors: Holger Hans Peter Freyther <zecke@selfish.org> |
| * Harald Welte <laforge@gnumonks.org> |
| * Pablo Neira Ayuso <pablo@gnumonks.org> |
| * |
| * 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.c |
| */ |
| |
| #include <assert.h> |
| #include <string.h> |
| #include <limits.h> |
| #include <osmocom/core/timer.h> |
| #include <osmocom/core/timer_compat.h> |
| #include <osmocom/core/linuxlist.h> |
| |
| /* These store the amount of time that we wait until next timer expires. */ |
| static struct timeval nearest; |
| static struct timeval *nearest_p; |
| |
| static struct rb_root timer_root = RB_ROOT; |
| |
| static void __add_timer(struct osmo_timer_list *timer) |
| { |
| struct rb_node **new = &(timer_root.rb_node); |
| struct rb_node *parent = NULL; |
| |
| while (*new) { |
| struct osmo_timer_list *this; |
| |
| this = container_of(*new, struct osmo_timer_list, node); |
| |
| parent = *new; |
| if (timercmp(&timer->timeout, &this->timeout, <)) |
| new = &((*new)->rb_left); |
| else |
| new = &((*new)->rb_right); |
| } |
| |
| rb_link_node(&timer->node, parent, new); |
| rb_insert_color(&timer->node, &timer_root); |
| } |
| |
| /*! \brief add a new timer to the timer management |
| * \param[in] timer the timer that should be added |
| */ |
| void osmo_timer_add(struct osmo_timer_list *timer) |
| { |
| osmo_timer_del(timer); |
| timer->active = 1; |
| INIT_LLIST_HEAD(&timer->list); |
| __add_timer(timer); |
| } |
| |
| /*! \brief schedule a timer at a given future relative time |
| * \param[in] timer the to-be-added timer |
| * \param[in] seconds number of seconds from now |
| * \param[in] microseconds number of microseconds from now |
| * |
| * This function can be used to (re-)schedule a given timer at a |
| * specified number of seconds+microseconds in the future. It will |
| * internally add it to the timer management data structures, thus |
| * osmo_timer_add() is automatically called. |
| */ |
| void |
| osmo_timer_schedule(struct osmo_timer_list *timer, int seconds, int microseconds) |
| { |
| struct timeval current_time; |
| |
| gettimeofday(¤t_time, NULL); |
| timer->timeout.tv_sec = seconds; |
| timer->timeout.tv_usec = microseconds; |
| timeradd(&timer->timeout, ¤t_time, &timer->timeout); |
| osmo_timer_add(timer); |
| } |
| |
| /*! \brief delete a timer from timer management |
| * \param[in] timer the to-be-deleted timer |
| * |
| * This function can be used to delete a previously added/scheduled |
| * timer from the timer management code. |
| */ |
| void osmo_timer_del(struct osmo_timer_list *timer) |
| { |
| if (timer->active) { |
| timer->active = 0; |
| rb_erase(&timer->node, &timer_root); |
| /* make sure this is not already scheduled for removal. */ |
| if (!llist_empty(&timer->list)) |
| llist_del_init(&timer->list); |
| } |
| } |
| |
| /*! \brief check if given timer is still pending |
| * \param[in] timer the to-be-checked timer |
| * \return 1 if pending, 0 otherwise |
| * |
| * This function can be used to determine whether a given timer |
| * has alredy expired (returns 0) or is still pending (returns 1) |
| */ |
| int osmo_timer_pending(struct osmo_timer_list *timer) |
| { |
| return timer->active; |
| } |
| |
| /*! \brief compute the remaining time of a timer |
| * \param[in] timer the to-be-checked timer |
| * \param[in] now the current time (NULL if not known) |
| * \param[out] remaining remaining time until timer fires |
| * \return 0 if timer has not expired yet, -1 if it has |
| * |
| * This function can be used to determine the amount of time |
| * remaining until the expiration of the timer. |
| */ |
| int osmo_timer_remaining(const struct osmo_timer_list *timer, |
| const struct timeval *now, |
| struct timeval *remaining) |
| { |
| struct timeval current_time; |
| |
| if (!now) |
| gettimeofday(¤t_time, NULL); |
| else |
| current_time = *now; |
| |
| timersub(&timer->timeout, ¤t_time, remaining); |
| |
| if (remaining->tv_sec < 0) |
| return -1; |
| |
| return 0; |
| } |
| |
| /*! \brief Determine time between now and the nearest timer |
| * \returns pointer to timeval of nearest timer, NULL if there is none |
| * |
| * if we have a nearest time return the delta between the current |
| * time and the time of the nearest timer. |
| * If the nearest timer timed out return NULL and then we will |
| * dispatch everything after the select |
| */ |
| struct timeval *osmo_timers_nearest(void) |
| { |
| /* nearest_p is exactly what we need already: NULL if nothing is |
| * waiting, {0,0} if we must dispatch immediately, and the correct |
| * delay if we need to wait */ |
| return nearest_p; |
| } |
| |
| static void update_nearest(struct timeval *cand, struct timeval *current) |
| { |
| if (cand->tv_sec != LONG_MAX) { |
| if (timercmp(cand, current, >)) |
| timersub(cand, current, &nearest); |
| else { |
| /* loop again inmediately */ |
| nearest.tv_sec = 0; |
| nearest.tv_usec = 0; |
| } |
| nearest_p = &nearest; |
| } else { |
| nearest_p = NULL; |
| } |
| } |
| |
| /*! \brief Find the nearest time and update nearest_p */ |
| void osmo_timers_prepare(void) |
| { |
| struct rb_node *node; |
| struct timeval current; |
| |
| gettimeofday(¤t, NULL); |
| |
| node = rb_first(&timer_root); |
| if (node) { |
| struct osmo_timer_list *this; |
| this = container_of(node, struct osmo_timer_list, node); |
| update_nearest(&this->timeout, ¤t); |
| } else { |
| nearest_p = NULL; |
| } |
| } |
| |
| /*! \brief fire all timers... and remove them */ |
| int osmo_timers_update(void) |
| { |
| struct timeval current_time; |
| struct rb_node *node; |
| struct llist_head timer_eviction_list; |
| struct osmo_timer_list *this; |
| int work = 0; |
| |
| gettimeofday(¤t_time, NULL); |
| |
| INIT_LLIST_HEAD(&timer_eviction_list); |
| for (node = rb_first(&timer_root); node; node = rb_next(node)) { |
| this = container_of(node, struct osmo_timer_list, node); |
| |
| if (timercmp(&this->timeout, ¤t_time, >)) |
| break; |
| |
| llist_add(&this->list, &timer_eviction_list); |
| } |
| |
| /* |
| * The callbacks might mess with our list and in this case |
| * even llist_for_each_entry_safe is not safe to use. To allow |
| * osmo_timer_del to be called from within the callback we need |
| * to restart the iteration for each element scheduled for removal. |
| * |
| * The problematic scenario is the following: Given two timers A |
| * and B that have expired at the same time. Thus, they are both |
| * in the eviction list in this order: A, then B. If we remove |
| * timer B from the A's callback, we continue with B in the next |
| * iteration step, leading to an access-after-release. |
| */ |
| restart: |
| llist_for_each_entry(this, &timer_eviction_list, list) { |
| osmo_timer_del(this); |
| this->cb(this->data); |
| work = 1; |
| goto restart; |
| } |
| |
| return work; |
| } |
| |
| /*! \brief Check how many timers we have in the system |
| * \returns number of \ref osmo_timer_list registered */ |
| int osmo_timers_check(void) |
| { |
| struct rb_node *node; |
| int i = 0; |
| |
| for (node = rb_first(&timer_root); node; node = rb_next(node)) { |
| i++; |
| } |
| return i; |
| } |
| |
| /*! @} */ |