freebsd-dev/contrib/pf/libevent/evbuffer.c

414 lines
9.5 KiB
C

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