From 5f75598c2804380ca07a5d52a411b5b64ba57fc3 Mon Sep 17 00:00:00 2001 From: Holger Freyther Date: Sat, 27 Dec 2008 09:42:59 +0000 Subject: [PATCH] Introduce a simple timer API.... One can use add_timer or schedule_timer to add a timer. After the timeout time has been reached the callback will be called. One can call add_time/schedule_timer and del_timer from within the callback. --- Makefile.am | 2 +- configure.in | 8 +- include/openbsc/timer.h | 70 ++++++++++++++++ src/Makefile.am | 2 +- src/select.c | 34 ++++---- src/timer.c | 168 +++++++++++++++++++++++++++++++++++++++ tests/Makefile.am | 1 + tests/timer/Makefile.am | 5 ++ tests/timer/timer_test.c | 62 +++++++++++++++ 9 files changed, 335 insertions(+), 17 deletions(-) create mode 100644 include/openbsc/timer.h create mode 100644 src/timer.c create mode 100644 tests/Makefile.am create mode 100644 tests/timer/Makefile.am create mode 100644 tests/timer/timer_test.c diff --git a/Makefile.am b/Makefile.am index b3a37eebc..1ba06046d 100644 --- a/Makefile.am +++ b/Makefile.am @@ -1,7 +1,7 @@ AUTOMAKE_OPTIONS = foreign dist-bzip2 1.6 INCLUDES = $(all_includes) -I$(top_srcdir)/include -SUBDIRS = include src +SUBDIRS = include src tests #dist-hook: # rm -rf `find $(distdir) -name .svn` diff --git a/configure.in b/configure.in index 1c4070ccf..034972a43 100644 --- a/configure.in +++ b/configure.in @@ -16,4 +16,10 @@ AC_CHECK_HEADERS(mISDNif.h) dnl Checks for typedefs, structures and compiler characteristics -AC_OUTPUT(include/openbsc/Makefile include/Makefile src/Makefile Makefile) +AC_OUTPUT( + include/openbsc/Makefile + include/Makefile + src/Makefile + tests/Makefile + tests/timer/Makefile + Makefile) diff --git a/include/openbsc/timer.h b/include/openbsc/timer.h new file mode 100644 index 000000000..e8dc91a84 --- /dev/null +++ b/include/openbsc/timer.h @@ -0,0 +1,70 @@ +/* + * (C) 2008 by Holger Hans Peter Freyther + * All Rights Reserved + * + * 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. + * + */ + +#ifndef TIMER_H +#define TIMER_H + +#include + +#include "linuxlist.h" + +/** + * Timer management: + * - Create a struct timer_list + * - Fill out timeout and use add_timer or + * use schedule_timer to schedule a timer in + * x seconds and microseconds from now... + * - Use del_timer to remove the timer + * + * Internally: + * - We hook into select.c to give a timeval of the + * nearest timer. On already passed timers we give + * it a 0 to immediately fire after the select + * - update_timers will call the callbacks and remove + * the timers. + * + */ +struct timer_list { + struct llist_head entry; + struct timeval timeout; + int active : 1; + int handled : 1; + + void (*cb)(void*); + void *data; +}; + +/** + * timer management + */ +void add_timer(struct timer_list *timer); +void schedule_timer(struct timer_list *timer, int seconds, int microseconds); +void del_timer(struct timer_list *timer); +int timer_pending(struct timer_list *timer); + + +/** + * internal timer list management + */ +struct timeval *nearest_timer(); +void prepare_timers(); +void update_timers(); + +#endif diff --git a/src/Makefile.am b/src/Makefile.am index bf55f2656..6209906c2 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -4,7 +4,7 @@ AM_CFLAGS=-Wall sbin_PROGRAMS = bsc_hack db_test bsc_hack_SOURCES = bsc_hack.c misdn.c abis_rsl.c abis_nm.c gsm_04_08.c gsm_data.c \ - gsm_subscriber.c msgb.c select.c chan_alloc.c + gsm_subscriber.c msgb.c select.c chan_alloc.c timer.c db_test_SOURCES = db_test.c db.c db_test_LDADD = -ldl -ldbi diff --git a/src/select.c b/src/select.c index 4af167047..b5d22c5b8 100644 --- a/src/select.c +++ b/src/select.c @@ -21,6 +21,7 @@ #include #include #include +#include static int maxfd = 0; static LLIST_HEAD(bsc_fds); @@ -74,24 +75,29 @@ int bsc_select_main() FD_SET(ufd->fd, &exceptset); } - i = select(maxfd+1, &readset, &writeset, &exceptset, NULL); - if (i > 0) { - /* call registered callback functions */ - llist_for_each_entry(ufd, &bsc_fds, list) { - int flags = 0; + prepare_timers(); + i = select(maxfd+1, &readset, &writeset, &exceptset, nearest_timer()); + if (i < 0) + return i; - if (FD_ISSET(ufd->fd, &readset)) - flags |= BSC_FD_READ; + /* fire timers */ + update_timers(); - if (FD_ISSET(ufd->fd, &writeset)) - flags |= BSC_FD_WRITE; + /* call registered callback functions */ + llist_for_each_entry(ufd, &bsc_fds, list) { + int flags = 0; - if (FD_ISSET(ufd->fd, &exceptset)) - flags |= BSC_FD_EXCEPT; + if (FD_ISSET(ufd->fd, &readset)) + flags |= BSC_FD_READ; - if (flags) - ufd->cb(ufd, flags); - } + if (FD_ISSET(ufd->fd, &writeset)) + flags |= BSC_FD_WRITE; + + if (FD_ISSET(ufd->fd, &exceptset)) + flags |= BSC_FD_EXCEPT; + + if (flags) + ufd->cb(ufd, flags); } return i; } diff --git a/src/timer.c b/src/timer.c new file mode 100644 index 000000000..158ee76b7 --- /dev/null +++ b/src/timer.c @@ -0,0 +1,168 @@ +/* + * (C) 2008 by Holger Hans Peter Freyther + * All Rights Reserved + * + * 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. + * + */ + +#include +#include +#include + +static LLIST_HEAD(timer_list); +static struct timeval s_nearest_time; +static struct timeval s_select_time; + +#define MICRO_SECONDS 1000000LL + +#define TIME_SMALLER(left, right) \ + (left.tv_sec*MICRO_SECONDS+left.tv_usec) <= (right.tv_sec*MICRO_SECONDS+right.tv_usec) + +void add_timer(struct timer_list *timer) +{ + struct timer_list *list_timer; + + /* TODO: Optimize and remember the closest item... */ + timer->active = 1; + + /* this might be called from within update_timers */ + llist_for_each_entry(list_timer, &timer_list, entry) + if (timer == list_timer) + return; + + llist_add(&timer->entry, &timer_list); +} + +void schedule_timer(struct timer_list *timer, int seconds, int microseconds) +{ + struct timeval current_time; + + gettimeofday(¤t_time, NULL); + unsigned long long currentTime = current_time.tv_sec * MICRO_SECONDS + current_time.tv_usec; + currentTime += seconds * MICRO_SECONDS + microseconds; + timer->timeout.tv_sec = currentTime / MICRO_SECONDS; + timer->timeout.tv_usec = currentTime % MICRO_SECONDS; + add_timer(timer); +} + +void del_timer(struct timer_list *timer) +{ + if (timer_pending(timer)) { + timer->active = 0; + llist_del(&timer->entry); + } +} + +int timer_pending(struct timer_list *timer) +{ + return timer->active; +} + +/* + * 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 *nearest_timer() +{ + struct timeval current_time; + + if (s_nearest_time.tv_sec == 0 && s_nearest_time.tv_usec == 0) + return NULL; + + if (gettimeofday(¤t_time, NULL) == -1) + return NULL; + + unsigned long long nearestTime = s_nearest_time.tv_sec * MICRO_SECONDS + s_nearest_time.tv_usec; + unsigned long long currentTime = current_time.tv_sec * MICRO_SECONDS + current_time.tv_usec; + + if (nearestTime < currentTime) { + s_select_time.tv_sec = 0; + s_select_time.tv_usec = 0; + } else { + s_select_time.tv_sec = (nearestTime - currentTime) / MICRO_SECONDS; + s_select_time.tv_usec = (nearestTime - currentTime) % MICRO_SECONDS; + } + + return &s_select_time; +} + +/* + * Find the nearest time and update s_nearest_time + */ +void prepare_timers() +{ + struct timer_list *timer, *nearest_timer = NULL; + llist_for_each_entry(timer, &timer_list, entry) { + if (!nearest_timer || TIME_SMALLER(timer->timeout, nearest_timer->timeout)) { + nearest_timer = timer; + } + } + + if (nearest_timer) { + s_nearest_time = nearest_timer->timeout; + } else { + memset(&s_nearest_time, 0, sizeof(struct timeval)); + } +} + +/* + * fire all timers... and remove them + */ +void update_timers() +{ + struct timeval current_time; + struct timer_list *timer, *tmp; + + gettimeofday(¤t_time, NULL); + + /* + * The callbacks might mess with our list and in this case + * even llist_for_each_entry_safe is not safe to use. To allow + * del_timer, add_timer, schedule_timer to be called from within + * the callback we jump through some loops. + * + * First we set the handled flag of each active timer to zero, + * then we iterate over the list and execute the callbacks. As the + * list might have been changed (specially the next) from within + * the callback we have to start over again. Once every callback + * is dispatched we will remove the non-active from the list. + * + * TODO: If this is a performance issue we can poison a global + * variable in add_timer and del_timer and only then restart. + */ + llist_for_each_entry(timer, &timer_list, entry) { + timer->handled = 0; + } + +restart: + llist_for_each_entry(timer, &timer_list, entry) { + if (!timer->handled && TIME_SMALLER(timer->timeout, current_time)) { + timer->handled = 1; + timer->active = 0; + (*timer->cb)(timer->data); + goto restart; + } + } + + llist_for_each_entry_safe(timer, tmp, &timer_list, entry) { + timer->handled = 0; + if (!timer->active) { + llist_del(&timer->entry); + } + } +} diff --git a/tests/Makefile.am b/tests/Makefile.am new file mode 100644 index 000000000..f7cfd549f --- /dev/null +++ b/tests/Makefile.am @@ -0,0 +1 @@ +SUBDIRS = timer diff --git a/tests/timer/Makefile.am b/tests/timer/Makefile.am new file mode 100644 index 000000000..726fb7ff2 --- /dev/null +++ b/tests/timer/Makefile.am @@ -0,0 +1,5 @@ +INCLUDES = $(all_includes) -I$(top_srcdir)/include +bin_PROGRAMS = timer_test + +timer_test_SOURCES = timer_test.c $(top_srcdir)/src/timer.c $(top_srcdir)/src/select.c + diff --git a/tests/timer/timer_test.c b/tests/timer/timer_test.c new file mode 100644 index 000000000..4d98aef42 --- /dev/null +++ b/tests/timer/timer_test.c @@ -0,0 +1,62 @@ +/* + * (C) 2008 by Holger Hans Peter Freyther + * All Rights Reserved + * + * 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. + * + */ + +#include + +#include +#include + +static void timer_fired(unsigned long data); + +static struct timer_list timer_one = { + .cb = timer_fired, + .data = (void*)1, +}; + +static struct timer_list timer_two = { + .cb = timer_fired, + .data = (void*)2, +}; + +static void timer_fired(unsigned long data) +{ + printf("Fired timer: %lu\n", data); + + if (data == 1) { + schedule_timer(&timer_one, 3, 0); + del_timer(&timer_two); + } else if (data == 2) { + printf("Should not be fired... bug in del_timer\n"); + } else { + printf("wtf... wrong data\n"); + } +} + +int main(int argc, char** argv) +{ + printf("Starting... timer\n"); + + schedule_timer(&timer_one, 3, 0); + schedule_timer(&timer_two, 5, 0); + + while (1) { + bsc_select_main(); + } +}