454 lines
11 KiB
C
454 lines
11 KiB
C
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/*
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* Copyright (c) 2002-2004 Niels Provos <provos@citi.umich.edu>
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* All rights reserved.
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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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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/types.h>
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#include "config.h"
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#ifdef HAVE_SYS_TIME_H
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#include <sys/time.h>
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#endif
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#ifdef HAVE_STDARG_H
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#include <stdarg.h>
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#endif
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#ifdef WIN32
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#include <winsock2.h>
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#endif
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#include "evutil.h"
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#include "event.h"
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/* prototypes */
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void bufferevent_read_pressure_cb(struct evbuffer *, size_t, size_t, void *);
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static int
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bufferevent_add(struct event *ev, int timeout)
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{
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struct timeval tv, *ptv = NULL;
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if (timeout) {
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evutil_timerclear(&tv);
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tv.tv_sec = timeout;
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ptv = &tv;
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}
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return (event_add(ev, ptv));
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}
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/*
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* This callback is executed when the size of the input buffer changes.
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* We use it to apply back pressure on the reading side.
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*/
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void
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bufferevent_read_pressure_cb(struct evbuffer *buf, size_t old, size_t now,
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void *arg) {
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struct bufferevent *bufev = arg;
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/*
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* If we are below the watermark then reschedule reading if it's
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* still enabled.
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*/
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if (bufev->wm_read.high == 0 || now < bufev->wm_read.high) {
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evbuffer_setcb(buf, NULL, NULL);
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if (bufev->enabled & EV_READ)
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bufferevent_add(&bufev->ev_read, bufev->timeout_read);
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}
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}
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static void
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bufferevent_readcb(int fd, short event, void *arg)
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{
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struct bufferevent *bufev = arg;
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int res = 0;
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short what = EVBUFFER_READ;
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size_t len;
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int howmuch = -1;
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if (event == EV_TIMEOUT) {
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what |= EVBUFFER_TIMEOUT;
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goto error;
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}
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/*
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* If we have a high watermark configured then we don't want to
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* read more data than would make us reach the watermark.
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*/
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if (bufev->wm_read.high != 0) {
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howmuch = bufev->wm_read.high - EVBUFFER_LENGTH(bufev->input);
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/* we might have lowered the watermark, stop reading */
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if (howmuch <= 0) {
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struct evbuffer *buf = bufev->input;
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event_del(&bufev->ev_read);
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evbuffer_setcb(buf,
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bufferevent_read_pressure_cb, bufev);
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return;
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}
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}
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res = evbuffer_read(bufev->input, fd, howmuch);
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if (res == -1) {
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if (errno == EAGAIN || errno == EINTR)
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goto reschedule;
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/* error case */
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what |= EVBUFFER_ERROR;
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} else if (res == 0) {
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/* eof case */
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what |= EVBUFFER_EOF;
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}
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if (res <= 0)
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goto error;
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bufferevent_add(&bufev->ev_read, bufev->timeout_read);
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/* See if this callbacks meets the water marks */
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len = EVBUFFER_LENGTH(bufev->input);
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if (bufev->wm_read.low != 0 && len < bufev->wm_read.low)
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return;
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if (bufev->wm_read.high != 0 && len >= bufev->wm_read.high) {
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struct evbuffer *buf = bufev->input;
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event_del(&bufev->ev_read);
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/* Now schedule a callback for us when the buffer changes */
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evbuffer_setcb(buf, bufferevent_read_pressure_cb, bufev);
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}
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/* Invoke the user callback - must always be called last */
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if (bufev->readcb != NULL)
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(*bufev->readcb)(bufev, bufev->cbarg);
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return;
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reschedule:
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bufferevent_add(&bufev->ev_read, bufev->timeout_read);
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return;
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error:
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(*bufev->errorcb)(bufev, what, bufev->cbarg);
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}
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static void
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bufferevent_writecb(int fd, short event, void *arg)
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{
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struct bufferevent *bufev = arg;
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int res = 0;
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short what = EVBUFFER_WRITE;
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if (event == EV_TIMEOUT) {
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what |= EVBUFFER_TIMEOUT;
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goto error;
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}
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if (EVBUFFER_LENGTH(bufev->output)) {
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res = evbuffer_write(bufev->output, fd);
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if (res == -1) {
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#ifndef WIN32
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/*todo. evbuffer uses WriteFile when WIN32 is set. WIN32 system calls do not
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*set errno. thus this error checking is not portable*/
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if (errno == EAGAIN ||
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errno == EINTR ||
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errno == EINPROGRESS)
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goto reschedule;
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/* error case */
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what |= EVBUFFER_ERROR;
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#else
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goto reschedule;
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#endif
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} else if (res == 0) {
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/* eof case */
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what |= EVBUFFER_EOF;
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}
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if (res <= 0)
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goto error;
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}
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if (EVBUFFER_LENGTH(bufev->output) != 0)
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bufferevent_add(&bufev->ev_write, bufev->timeout_write);
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/*
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* Invoke the user callback if our buffer is drained or below the
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* low watermark.
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*/
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if (bufev->writecb != NULL &&
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EVBUFFER_LENGTH(bufev->output) <= bufev->wm_write.low)
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(*bufev->writecb)(bufev, bufev->cbarg);
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return;
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reschedule:
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if (EVBUFFER_LENGTH(bufev->output) != 0)
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bufferevent_add(&bufev->ev_write, bufev->timeout_write);
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return;
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error:
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(*bufev->errorcb)(bufev, what, bufev->cbarg);
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}
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/*
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* Create a new buffered event object.
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*
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* The read callback is invoked whenever we read new data.
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* The write callback is invoked whenever the output buffer is drained.
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* The error callback is invoked on a write/read error or on EOF.
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*
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* Both read and write callbacks maybe NULL. The error callback is not
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* allowed to be NULL and have to be provided always.
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*/
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struct bufferevent *
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bufferevent_new(int fd, evbuffercb readcb, evbuffercb writecb,
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everrorcb errorcb, void *cbarg)
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{
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struct bufferevent *bufev;
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if ((bufev = calloc(1, sizeof(struct bufferevent))) == NULL)
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return (NULL);
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if ((bufev->input = evbuffer_new()) == NULL) {
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free(bufev);
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return (NULL);
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}
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if ((bufev->output = evbuffer_new()) == NULL) {
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evbuffer_free(bufev->input);
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free(bufev);
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return (NULL);
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}
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event_set(&bufev->ev_read, fd, EV_READ, bufferevent_readcb, bufev);
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event_set(&bufev->ev_write, fd, EV_WRITE, bufferevent_writecb, bufev);
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bufferevent_setcb(bufev, readcb, writecb, errorcb, cbarg);
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/*
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* Set to EV_WRITE so that using bufferevent_write is going to
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* trigger a callback. Reading needs to be explicitly enabled
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* because otherwise no data will be available.
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*/
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bufev->enabled = EV_WRITE;
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return (bufev);
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}
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void
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bufferevent_setcb(struct bufferevent *bufev,
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evbuffercb readcb, evbuffercb writecb, everrorcb errorcb, void *cbarg)
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{
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bufev->readcb = readcb;
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bufev->writecb = writecb;
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bufev->errorcb = errorcb;
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bufev->cbarg = cbarg;
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}
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void
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bufferevent_setfd(struct bufferevent *bufev, int fd)
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{
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event_del(&bufev->ev_read);
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event_del(&bufev->ev_write);
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event_set(&bufev->ev_read, fd, EV_READ, bufferevent_readcb, bufev);
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event_set(&bufev->ev_write, fd, EV_WRITE, bufferevent_writecb, bufev);
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if (bufev->ev_base != NULL) {
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event_base_set(bufev->ev_base, &bufev->ev_read);
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event_base_set(bufev->ev_base, &bufev->ev_write);
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}
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/* might have to manually trigger event registration */
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}
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int
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bufferevent_priority_set(struct bufferevent *bufev, int priority)
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{
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if (event_priority_set(&bufev->ev_read, priority) == -1)
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return (-1);
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if (event_priority_set(&bufev->ev_write, priority) == -1)
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return (-1);
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return (0);
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}
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/* Closing the file descriptor is the responsibility of the caller */
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void
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bufferevent_free(struct bufferevent *bufev)
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{
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event_del(&bufev->ev_read);
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event_del(&bufev->ev_write);
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evbuffer_free(bufev->input);
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evbuffer_free(bufev->output);
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free(bufev);
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}
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/*
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* Returns 0 on success;
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* -1 on failure.
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*/
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int
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bufferevent_write(struct bufferevent *bufev, const void *data, size_t size)
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{
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int res;
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res = evbuffer_add(bufev->output, data, size);
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if (res == -1)
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return (res);
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/* If everything is okay, we need to schedule a write */
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if (size > 0 && (bufev->enabled & EV_WRITE))
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bufferevent_add(&bufev->ev_write, bufev->timeout_write);
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return (res);
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}
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int
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bufferevent_write_buffer(struct bufferevent *bufev, struct evbuffer *buf)
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{
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int res;
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res = bufferevent_write(bufev, buf->buffer, buf->off);
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if (res != -1)
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evbuffer_drain(buf, buf->off);
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return (res);
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}
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size_t
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bufferevent_read(struct bufferevent *bufev, void *data, size_t size)
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{
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struct evbuffer *buf = bufev->input;
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if (buf->off < size)
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size = buf->off;
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/* Copy the available data to the user buffer */
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memcpy(data, buf->buffer, size);
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if (size)
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evbuffer_drain(buf, size);
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return (size);
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}
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int
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bufferevent_enable(struct bufferevent *bufev, short event)
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{
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if (event & EV_READ) {
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if (bufferevent_add(&bufev->ev_read, bufev->timeout_read) == -1)
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return (-1);
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}
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if (event & EV_WRITE) {
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if (bufferevent_add(&bufev->ev_write, bufev->timeout_write) == -1)
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return (-1);
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}
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bufev->enabled |= event;
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return (0);
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}
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int
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bufferevent_disable(struct bufferevent *bufev, short event)
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{
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if (event & EV_READ) {
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|
|
if (event_del(&bufev->ev_read) == -1)
|
||
|
|
return (-1);
|
||
|
|
}
|
||
|
|
if (event & EV_WRITE) {
|
||
|
|
if (event_del(&bufev->ev_write) == -1)
|
||
|
|
return (-1);
|
||
|
|
}
|
||
|
|
|
||
|
|
bufev->enabled &= ~event;
|
||
|
|
return (0);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Sets the read and write timeout for a buffered event.
|
||
|
|
*/
|
||
|
|
|
||
|
|
void
|
||
|
|
bufferevent_settimeout(struct bufferevent *bufev,
|
||
|
|
int timeout_read, int timeout_write) {
|
||
|
|
bufev->timeout_read = timeout_read;
|
||
|
|
bufev->timeout_write = timeout_write;
|
||
|
|
|
||
|
|
if (event_pending(&bufev->ev_read, EV_READ, NULL))
|
||
|
|
bufferevent_add(&bufev->ev_read, timeout_read);
|
||
|
|
if (event_pending(&bufev->ev_write, EV_WRITE, NULL))
|
||
|
|
bufferevent_add(&bufev->ev_write, timeout_write);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Sets the water marks
|
||
|
|
*/
|
||
|
|
|
||
|
|
void
|
||
|
|
bufferevent_setwatermark(struct bufferevent *bufev, short events,
|
||
|
|
size_t lowmark, size_t highmark)
|
||
|
|
{
|
||
|
|
if (events & EV_READ) {
|
||
|
|
bufev->wm_read.low = lowmark;
|
||
|
|
bufev->wm_read.high = highmark;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (events & EV_WRITE) {
|
||
|
|
bufev->wm_write.low = lowmark;
|
||
|
|
bufev->wm_write.high = highmark;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* If the watermarks changed then see if we should call read again */
|
||
|
|
bufferevent_read_pressure_cb(bufev->input,
|
||
|
|
0, EVBUFFER_LENGTH(bufev->input), bufev);
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
bufferevent_base_set(struct event_base *base, struct bufferevent *bufev)
|
||
|
|
{
|
||
|
|
int res;
|
||
|
|
|
||
|
|
bufev->ev_base = base;
|
||
|
|
|
||
|
|
res = event_base_set(base, &bufev->ev_read);
|
||
|
|
if (res == -1)
|
||
|
|
return (res);
|
||
|
|
|
||
|
|
res = event_base_set(base, &bufev->ev_write);
|
||
|
|
return (res);
|
||
|
|
}
|