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Diffstat (limited to 'tevent_timed.c')
| -rw-r--r-- | tevent_timed.c | 477 |
1 files changed, 477 insertions, 0 deletions
diff --git a/tevent_timed.c b/tevent_timed.c new file mode 100644 index 0000000..67e39ed --- /dev/null +++ b/tevent_timed.c @@ -0,0 +1,477 @@ +/* + Unix SMB/CIFS implementation. + + common events code for timed events + + Copyright (C) Andrew Tridgell 2003-2006 + Copyright (C) Stefan Metzmacher 2005-2009 + + ** NOTE! The following LGPL license applies to the tevent + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see <http://www.gnu.org/licenses/>. +*/ + +#include "replace.h" +#include "system/time.h" +#define TEVENT_DEPRECATED 1 +#include "tevent.h" +#include "tevent_internal.h" +#include "tevent_util.h" + +/** + compare two timeval structures. + Return -1 if tv1 < tv2 + Return 0 if tv1 == tv2 + Return 1 if tv1 > tv2 +*/ +int tevent_timeval_compare(const struct timeval *tv1, const struct timeval *tv2) +{ + if (tv1->tv_sec > tv2->tv_sec) return 1; + if (tv1->tv_sec < tv2->tv_sec) return -1; + if (tv1->tv_usec > tv2->tv_usec) return 1; + if (tv1->tv_usec < tv2->tv_usec) return -1; + return 0; +} + +/** + return a zero timeval +*/ +struct timeval tevent_timeval_zero(void) +{ + struct timeval tv; + tv.tv_sec = 0; + tv.tv_usec = 0; + return tv; +} + +/** + return a timeval for the current time +*/ +struct timeval tevent_timeval_current(void) +{ + struct timeval tv; + gettimeofday(&tv, NULL); + return tv; +} + +/** + return a timeval struct with the given elements +*/ +struct timeval tevent_timeval_set(uint32_t secs, uint32_t usecs) +{ + struct timeval tv; + tv.tv_sec = secs; + tv.tv_usec = usecs; + return tv; +} + +/** + return the difference between two timevals as a timeval + if tv1 comes after tv2, then return a zero timeval + (this is *tv2 - *tv1) +*/ +struct timeval tevent_timeval_until(const struct timeval *tv1, + const struct timeval *tv2) +{ + struct timeval t; + if (tevent_timeval_compare(tv1, tv2) >= 0) { + return tevent_timeval_zero(); + } + t.tv_sec = tv2->tv_sec - tv1->tv_sec; + if (tv1->tv_usec > tv2->tv_usec) { + t.tv_sec--; + t.tv_usec = 1000000 - (tv1->tv_usec - tv2->tv_usec); + } else { + t.tv_usec = tv2->tv_usec - tv1->tv_usec; + } + return t; +} + +/** + return true if a timeval is zero +*/ +bool tevent_timeval_is_zero(const struct timeval *tv) +{ + return tv->tv_sec == 0 && tv->tv_usec == 0; +} + +struct timeval tevent_timeval_add(const struct timeval *tv, uint32_t secs, + uint32_t usecs) +{ + struct timeval tv2 = *tv; + tv2.tv_sec += secs; + tv2.tv_usec += usecs; + tv2.tv_sec += tv2.tv_usec / 1000000; + tv2.tv_usec = tv2.tv_usec % 1000000; + + return tv2; +} + +/** + return a timeval in the future with a specified offset +*/ +struct timeval tevent_timeval_current_ofs(uint32_t secs, uint32_t usecs) +{ + struct timeval tv = tevent_timeval_current(); + return tevent_timeval_add(&tv, secs, usecs); +} + +/* + destroy a timed event +*/ +static int tevent_common_timed_destructor(struct tevent_timer *te) +{ + if (te->destroyed) { + tevent_common_check_double_free(te, "tevent_timer double free"); + goto done; + } + te->destroyed = true; + + if (te->event_ctx == NULL) { + return 0; + } + + tevent_debug(te->event_ctx, TEVENT_DEBUG_TRACE, + "Destroying timer event %p \"%s\"\n", + te, te->handler_name); + + if (te->event_ctx->last_zero_timer == te) { + te->event_ctx->last_zero_timer = DLIST_PREV(te); + } + + tevent_trace_timer_callback(te->event_ctx, te, TEVENT_EVENT_TRACE_DETACH); + DLIST_REMOVE(te->event_ctx->timer_events, te); + + te->event_ctx = NULL; +done: + if (te->busy) { + return -1; + } + te->wrapper = NULL; + + return 0; +} + +static void tevent_common_insert_timer(struct tevent_context *ev, + struct tevent_timer *te, + bool optimize_zero) +{ + struct tevent_timer *prev_te = NULL; + + if (te->destroyed) { + tevent_abort(ev, "tevent_timer use after free"); + return; + } + + /* keep the list ordered */ + if (optimize_zero && tevent_timeval_is_zero(&te->next_event)) { + /* + * Some callers use zero tevent_timer + * instead of tevent_immediate events. + * + * As these can happen very often, + * we remember the last zero timer + * in the list. + */ + prev_te = ev->last_zero_timer; + ev->last_zero_timer = te; + } else { + struct tevent_timer *cur_te; + + /* + * we traverse the list from the tail + * because it's much more likely that + * timers are added at the end of the list + */ + for (cur_te = DLIST_TAIL(ev->timer_events); + cur_te != NULL; + cur_te = DLIST_PREV(cur_te)) + { + int ret; + + /* + * if the new event comes before the current + * we continue searching + */ + ret = tevent_timeval_compare(&te->next_event, + &cur_te->next_event); + if (ret < 0) { + continue; + } + + break; + } + + prev_te = cur_te; + } + + tevent_trace_timer_callback(te->event_ctx, te, TEVENT_EVENT_TRACE_ATTACH); + DLIST_ADD_AFTER(ev->timer_events, te, prev_te); +} + +/* + add a timed event + return NULL on failure (memory allocation error) +*/ +static struct tevent_timer *tevent_common_add_timer_internal( + struct tevent_context *ev, + TALLOC_CTX *mem_ctx, + struct timeval next_event, + tevent_timer_handler_t handler, + void *private_data, + const char *handler_name, + const char *location, + bool optimize_zero) +{ + struct tevent_timer *te; + + te = talloc(mem_ctx?mem_ctx:ev, struct tevent_timer); + if (te == NULL) return NULL; + + *te = (struct tevent_timer) { + .event_ctx = ev, + .next_event = next_event, + .handler = handler, + .private_data = private_data, + .handler_name = handler_name, + .location = location, + }; + + if (ev->timer_events == NULL) { + ev->last_zero_timer = NULL; + } + + tevent_common_insert_timer(ev, te, optimize_zero); + + talloc_set_destructor(te, tevent_common_timed_destructor); + + + tevent_debug(ev, TEVENT_DEBUG_TRACE, + "Added timed event \"%s\": %p\n", + handler_name, te); + return te; +} + +struct tevent_timer *tevent_common_add_timer(struct tevent_context *ev, + TALLOC_CTX *mem_ctx, + struct timeval next_event, + tevent_timer_handler_t handler, + void *private_data, + const char *handler_name, + const char *location) +{ + /* + * do not use optimization, there are broken Samba + * versions which use tevent_common_add_timer() + * without using tevent_common_loop_timer_delay(), + * it just uses DLIST_REMOVE(ev->timer_events, te) + * and would leave ev->last_zero_timer behind. + */ + return tevent_common_add_timer_internal(ev, mem_ctx, next_event, + handler, private_data, + handler_name, location, + false); +} + +struct tevent_timer *tevent_common_add_timer_v2(struct tevent_context *ev, + TALLOC_CTX *mem_ctx, + struct timeval next_event, + tevent_timer_handler_t handler, + void *private_data, + const char *handler_name, + const char *location) +{ + /* + * Here we turn on last_zero_timer optimization + */ + return tevent_common_add_timer_internal(ev, mem_ctx, next_event, + handler, private_data, + handler_name, location, + true); +} + +void tevent_update_timer(struct tevent_timer *te, struct timeval next_event) +{ + struct tevent_context *ev = te->event_ctx; + + if (ev->last_zero_timer == te) { + te->event_ctx->last_zero_timer = DLIST_PREV(te); + } + tevent_trace_timer_callback(te->event_ctx, te, TEVENT_EVENT_TRACE_DETACH); + DLIST_REMOVE(ev->timer_events, te); + + te->next_event = next_event; + + /* + * Not doing the zero_timer optimization. This is for new code + * that should know about immediates. + */ + tevent_common_insert_timer(ev, te, false); +} + +int tevent_common_invoke_timer_handler(struct tevent_timer *te, + struct timeval current_time, + bool *removed) +{ + struct tevent_context *handler_ev = te->event_ctx; + + if (removed != NULL) { + *removed = false; + } + + if (te->event_ctx == NULL) { + return 0; + } + + /* + * We need to remove the timer from the list before calling the + * handler because in a semi-async inner event loop called from the + * handler we don't want to come across this event again -- vl + */ + if (te->event_ctx->last_zero_timer == te) { + te->event_ctx->last_zero_timer = DLIST_PREV(te); + } + DLIST_REMOVE(te->event_ctx->timer_events, te); + + tevent_debug(te->event_ctx, TEVENT_DEBUG_TRACE, + "Running timer event %p \"%s\"\n", + te, te->handler_name); + + /* + * If the timed event was registered for a zero current_time, + * then we pass a zero timeval here too! To avoid the + * overhead of gettimeofday() calls. + * + * otherwise we pass the current time + */ + te->busy = true; + if (te->wrapper != NULL) { + handler_ev = te->wrapper->wrap_ev; + + tevent_wrapper_push_use_internal(handler_ev, te->wrapper); + te->wrapper->ops->before_timer_handler( + te->wrapper->wrap_ev, + te->wrapper->private_state, + te->wrapper->main_ev, + te, + te->next_event, + current_time, + te->handler_name, + te->location); + } + tevent_trace_timer_callback(te->event_ctx, te, TEVENT_EVENT_TRACE_BEFORE_HANDLER); + te->handler(handler_ev, te, current_time, te->private_data); + if (te->wrapper != NULL) { + te->wrapper->ops->after_timer_handler( + te->wrapper->wrap_ev, + te->wrapper->private_state, + te->wrapper->main_ev, + te, + te->next_event, + current_time, + te->handler_name, + te->location); + tevent_wrapper_pop_use_internal(handler_ev, te->wrapper); + } + te->busy = false; + + tevent_debug(te->event_ctx, TEVENT_DEBUG_TRACE, + "Ending timer event %p \"%s\"\n", + te, te->handler_name); + + /* The callback was already called when freed from the handler. */ + if (!te->destroyed) { + tevent_trace_timer_callback(te->event_ctx, te, TEVENT_EVENT_TRACE_DETACH); + } + + te->wrapper = NULL; + te->event_ctx = NULL; + talloc_set_destructor(te, NULL); + TALLOC_FREE(te); + + if (removed != NULL) { + *removed = true; + } + + return 0; +} +/* + do a single event loop using the events defined in ev + + return the delay until the next timed event, + or zero if a timed event was triggered +*/ +struct timeval tevent_common_loop_timer_delay(struct tevent_context *ev) +{ + struct timeval current_time = tevent_timeval_zero(); + struct tevent_timer *te = ev->timer_events; + int ret; + + if (!te) { + /* have a default tick time of 30 seconds. This guarantees + that code that uses its own timeout checking will be + able to proceed eventually */ + return tevent_timeval_set(30, 0); + } + + /* + * work out the right timeout for the next timed event + * + * avoid the syscall to gettimeofday() if the timed event should + * be triggered directly + * + * if there's a delay till the next timed event, we're done + * with just returning the delay + */ + if (!tevent_timeval_is_zero(&te->next_event)) { + struct timeval delay; + + current_time = tevent_timeval_current(); + + delay = tevent_timeval_until(¤t_time, &te->next_event); + if (!tevent_timeval_is_zero(&delay)) { + return delay; + } + } + + /* + * ok, we have a timed event that we'll process ... + */ + ret = tevent_common_invoke_timer_handler(te, current_time, NULL); + if (ret != 0) { + tevent_abort(ev, "tevent_common_invoke_timer_handler() failed"); + } + + return tevent_timeval_zero(); +} + +void tevent_timer_set_tag(struct tevent_timer *te, uint64_t tag) +{ + if (te == NULL) { + return; + } + + te->tag = tag; +} + +uint64_t tevent_timer_get_tag(const struct tevent_timer *te) +{ + if (te == NULL) { + return 0; + } + + return te->tag; +} |