178 lines
5.8 KiB
C
178 lines
5.8 KiB
C
/*
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* mini-event.h - micro implementation of libevent api, using select() only.
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*
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* Copyright (c) 2007, NLnet Labs. All rights reserved.
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*
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* This software is open source.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of the NLNET LABS nor the names of its contributors may
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* be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \file
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* This file implements part of the event(3) libevent api.
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* The back end is only select. Max number of fds is limited.
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* Max number of signals is limited, one handler per signal only.
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* And one handler per fd.
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*
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* Although limited to select() and a max (1024) open fds, it
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* is efficient:
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* o dispatch call caches fd_sets to use.
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* o handler calling takes time ~ to the number of fds.
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* o timeouts are stored in a redblack tree, sorted, so take log(n).
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* Timeouts are only accurate to the second (no subsecond accuracy).
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* To avoid cpu hogging, fractional timeouts are rounded up to a whole second.
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*/
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#ifndef MINI_EVENT_H
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#define MINI_EVENT_H
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#if defined(USE_MINI_EVENT) && !defined(USE_WINSOCK)
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#ifndef HAVE_EVENT_BASE_FREE
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#define HAVE_EVENT_BASE_FREE
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#endif
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/** event timeout */
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#define EV_TIMEOUT 0x01
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/** event fd readable */
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#define EV_READ 0x02
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/** event fd writable */
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#define EV_WRITE 0x04
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/** event signal */
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#define EV_SIGNAL 0x08
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/** event must persist */
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#define EV_PERSIST 0x10
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/* needs our redblack tree */
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#include "rbtree.h"
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/** max number of file descriptors to support */
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#define MAX_FDS 1024
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/** max number of signals to support */
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#define MAX_SIG 32
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/** event base */
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struct event_base
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{
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/** sorted by timeout (absolute), ptr */
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rbtree_t* times;
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/** array of 0 - maxfd of ptr to event for it */
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struct event** fds;
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/** max fd in use */
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int maxfd;
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/** capacity - size of the fds array */
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int capfd;
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/* fdset for read write, for fds ready, and added */
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fd_set
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/** fds for reading */
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reads,
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/** fds for writing */
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writes,
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/** fds determined ready for use */
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ready,
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/** ready plus newly added events. */
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content;
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/** array of 0 - maxsig of ptr to event for it */
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struct event** signals;
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/** if we need to exit */
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int need_to_exit;
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/** where to store time in seconds */
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uint32_t* time_secs;
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/** where to store time in microseconds */
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struct timeval* time_tv;
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};
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/**
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* Event structure. Has some of the event elements.
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*/
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struct event {
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/** node in timeout rbtree */
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rbnode_t node;
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/** is event already added */
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int added;
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/** event base it belongs to */
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struct event_base *ev_base;
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/** fd to poll or -1 for timeouts. signal number for sigs. */
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int ev_fd;
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/** what events this event is interested in, see EV_.. above. */
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short ev_events;
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/** timeout value */
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struct timeval ev_timeout;
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/** callback to call: fd, eventbits, userarg */
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void (*ev_callback)(int, short, void *arg);
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/** callback user arg */
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void *ev_arg;
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};
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/* function prototypes (some are as they appear in event.h) */
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/** create event base */
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void *event_init(uint32_t* time_secs, struct timeval* time_tv);
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/** get version */
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const char *event_get_version(void);
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/** get polling method, select */
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const char *event_get_method(void);
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/** run select in a loop */
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int event_base_dispatch(struct event_base *);
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/** exit that loop */
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int event_base_loopexit(struct event_base *, struct timeval *);
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/** free event base. Free events yourself */
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void event_base_free(struct event_base *);
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/** set content of event */
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void event_set(struct event *, int, short, void (*)(int, short, void *), void *);
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/** add event to a base. You *must* call this for every event. */
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int event_base_set(struct event_base *, struct event *);
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/** add event to make it active. You may not change it with event_set anymore */
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int event_add(struct event *, struct timeval *);
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/** remove event. You may change it again */
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int event_del(struct event *);
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/** add a timer */
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#define evtimer_add(ev, tv) event_add(ev, tv)
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/** remove a timer */
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#define evtimer_del(ev) event_del(ev)
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/* uses different implementation. Cannot mix fd/timeouts and signals inside
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* the same struct event. create several event structs for that. */
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/** install signal handler */
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int signal_add(struct event *, struct timeval *);
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/** set signal event contents */
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#define signal_set(ev, x, cb, arg) \
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event_set(ev, x, EV_SIGNAL|EV_PERSIST, cb, arg)
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/** remove signal handler */
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int signal_del(struct event *);
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#endif /* USE_MINI_EVENT and not USE_WINSOCK */
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/** compare events in tree, based on timevalue, ptr for uniqueness */
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int mini_ev_cmp(const void* a, const void* b);
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#endif /* MINI_EVENT_H */
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