poll.c

apache的软件linux版本

/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "apr.h"
#include "apr_poll.h"
#include "apr_time.h"
#include "apr_portable.h"
#include "apr_arch_networkio.h"
#include "apr_arch_file_io.h"
#if HAVE_POLL_H
#include <poll.h>
#endif
#if HAVE_SYS_POLL_H
#include <sys/poll.h>
#endif
#if HAVE_ALLOCA_H
#include <alloca.h>
#endif

#ifdef NETWARE
#define HAS_SOCKETS(dt) (dt == APR_POLL_SOCKET) ? 1 : 0
#define HAS_PIPES(dt) (dt == APR_POLL_FILE) ? 1 : 0
#endif

#ifdef HAVE_POLL    /* We can just use poll to do our socket polling. */

static apr_int16_t get_event(apr_int16_t event)
{
    apr_int16_t rv = 0;

    if (event & APR_POLLIN)
        rv |= POLLIN;        
    if (event & APR_POLLPRI)
        rv |= POLLPRI;        
    if (event & APR_POLLOUT)
        rv |= POLLOUT;       
    if (event & APR_POLLERR)
        rv |= POLLERR;        
    if (event & APR_POLLHUP)
        rv |= POLLHUP;        
    if (event & APR_POLLNVAL)
        rv |= POLLNVAL;        

    return rv;
}

static apr_int16_t get_revent(apr_int16_t event)
{
    apr_int16_t rv = 0;

    if (event & POLLIN)
        rv |= APR_POLLIN;
    if (event & POLLPRI)
        rv |= APR_POLLPRI;
    if (event & POLLOUT)
        rv |= APR_POLLOUT;
    if (event & POLLERR)
        rv |= APR_POLLERR;
    if (event & POLLHUP)
        rv |= APR_POLLHUP;
    if (event & POLLNVAL)
        rv |= APR_POLLNVAL;

    return rv;
}        

#define SMALL_POLLSET_LIMIT  8

APR_DECLARE(apr_status_t) apr_poll(apr_pollfd_t *aprset, apr_int32_t num,
                      apr_int32_t *nsds, apr_interval_time_t timeout)
{
    int i, num_to_poll;
#ifdef HAVE_VLA
    /* XXX: I trust that this is a segv when insufficient stack exists? */
    struct pollfd pollset[num];
#elif defined(HAVE_ALLOCA)
    struct pollfd *pollset = alloca(sizeof(struct pollfd) * num);
    if (!pollset)
        return APR_ENOMEM;
#else
    struct pollfd tmp_pollset[SMALL_POLLSET_LIMIT];
    struct pollfd *pollset;

    if (num <= SMALL_POLLSET_LIMIT) {
        pollset = tmp_pollset;
    }
    else {
        /* This does require O(n) to copy the descriptors to the internal
         * mapping.
         */
        pollset = malloc(sizeof(struct pollfd) * num);
        /* The other option is adding an apr_pool_abort() fn to invoke
         * the pool's out of memory handler
         */
        if (!pollset)
            return APR_ENOMEM;
    }
#endif
    for (i = 0; i < num; i++) {
        if (aprset[i].desc_type == APR_POLL_SOCKET) {
            pollset[i].fd = aprset[i].desc.s->socketdes;
        }
        else if (aprset[i].desc_type == APR_POLL_FILE) {
            pollset[i].fd = aprset[i].desc.f->filedes;
        }
        else {
            break;
        }
        pollset[i].events = get_event(aprset[i].reqevents);
    }
    num_to_poll = i;

    if (timeout > 0) {
        timeout /= 1000; /* convert microseconds to milliseconds */
    }

    i = poll(pollset, num_to_poll, timeout);
    (*nsds) = i;

    for (i = 0; i < num; i++) {
        aprset[i].rtnevents = get_revent(pollset[i].revents);
    }
    
#if !defined(HAVE_VLA) && !defined(HAVE_ALLOCA)
    if (num > SMALL_POLLSET_LIMIT) {
        free(pollset);
    }
#endif

    if ((*nsds) < 0) {
        return apr_get_netos_error();
    }
    if ((*nsds) == 0) {
        return APR_TIMEUP;
    }
    return APR_SUCCESS;
}


#else    /* Use select to mimic poll */

APR_DECLARE(apr_status_t) apr_poll(apr_pollfd_t *aprset, int num, apr_int32_t *nsds, 
		    apr_interval_time_t timeout)
{
    fd_set readset, writeset, exceptset;
    int rv, i;
    int maxfd = -1;
    struct timeval tv, *tvptr;
#ifdef NETWARE
    apr_datatype_e set_type = APR_NO_DESC;
#endif

    if (timeout < 0) {
        tvptr = NULL;
    }
    else {
        tv.tv_sec = (long)apr_time_sec(timeout);
        tv.tv_usec = (long)apr_time_usec(timeout);
        tvptr = &tv;
    }

    FD_ZERO(&readset);
    FD_ZERO(&writeset);
    FD_ZERO(&exceptset);

    for (i = 0; i < num; i++) {
        apr_os_sock_t fd;

        aprset[i].rtnevents = 0;

        if (aprset[i].desc_type == APR_POLL_SOCKET) {
#ifdef NETWARE
            if (HAS_PIPES(set_type)) {
                return APR_EBADF;
            }
            else {
                set_type = APR_POLL_SOCKET;
            }
#endif
            fd = aprset[i].desc.s->socketdes;
        }
        else if (aprset[i].desc_type == APR_POLL_FILE) {
#if !APR_FILES_AS_SOCKETS
            return APR_EBADF;
#else
#ifdef NETWARE
            if (aprset[i].desc.f->is_pipe && !HAS_SOCKETS(set_type)) {
                set_type = APR_POLL_FILE;
            }
            else
                return APR_EBADF;
#endif /* NETWARE */

            fd = aprset[i].desc.f->filedes;

#endif /* APR_FILES_AS_SOCKETS */
        }
        else {
            break;
        }
#if !defined(WIN32) && !defined(NETWARE) /* socket sets handled with array of handles */
        if (fd >= FD_SETSIZE) {
            /* XXX invent new error code so application has a clue */
            return APR_EBADF;
        }
#endif
        if (aprset[i].reqevents & APR_POLLIN) {
            FD_SET(fd, &readset);
        }
        if (aprset[i].reqevents & APR_POLLOUT) {
            FD_SET(fd, &writeset);
        }
        if (aprset[i].reqevents & 
            (APR_POLLPRI | APR_POLLERR | APR_POLLHUP | APR_POLLNVAL)) {
            FD_SET(fd, &exceptset);
        }
        if ((int)fd > maxfd) {
            maxfd = (int)fd;
        }
    }

#ifdef NETWARE
    if (HAS_PIPES(set_type)) {
        rv = pipe_select(maxfd + 1, &readset, &writeset, &exceptset, tvptr);
    }
    else {
#endif

    rv = select(maxfd + 1, &readset, &writeset, &exceptset, tvptr);

#ifdef NETWARE
    }
#endif

    (*nsds) = rv;
    if ((*nsds) == 0) {
        return APR_TIMEUP;
    }
    if ((*nsds) < 0) {
        return apr_get_netos_error();
    }

    for (i = 0; i < num; i++) {
        apr_os_sock_t fd;

        if (aprset[i].desc_type == APR_POLL_SOCKET) {
            fd = aprset[i].desc.s->socketdes;
        }
        else if (aprset[i].desc_type == APR_POLL_FILE) {
#if !APR_FILES_AS_SOCKETS
            return APR_EBADF;
#else
            fd = aprset[i].desc.f->filedes;
#endif
        }
        else {
            break;
        }
        if (FD_ISSET(fd, &readset)) {
            aprset[i].rtnevents |= APR_POLLIN;
        }
        if (FD_ISSET(fd, &writeset)) {
            aprset[i].rtnevents |= APR_POLLOUT;
        }
        if (FD_ISSET(fd, &exceptset)) {
            aprset[i].rtnevents |= APR_POLLERR;
        }
    }

    return APR_SUCCESS;
}

#endif 


struct apr_pollset_t {
    apr_uint32_t nelts;
    apr_uint32_t nalloc;
#ifdef HAVE_POLL
    struct pollfd *pollset;
#else
    fd_set readset, writeset, exceptset;
    int maxfd;
#endif
    apr_pollfd_t *query_set;
    apr_pollfd_t *result_set;
    apr_pool_t *pool;
#ifdef NETWARE
    int set_type;
#endif