elemental-ircd/libratbox/src/devpoll.c

/*
 *  ircd-ratbox: A slightly useful ircd.
 *  s_bsd_devpoll.c: /dev/poll compatible network routines.
 *
 *  Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
 *  Copyright (C) 1996-2002 Hybrid Development Team
 *  Copyright (C) 2001 Adrian Chadd <adrian@creative.net.au>
 *  Copyright (C) 2002-2005 ircd-ratbox development team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
 *  USA
 *
 */
#include <libratbox_config.h>
#include <ratbox_lib.h>
#include <commio-int.h>
#include <fcntl.h>

#if defined(HAVE_DEVPOLL) && (HAVE_SYS_DEVPOLL_H)
#include <sys/devpoll.h>

static int dpfd;
static int maxfd;
static short *fdmask;
static void devpoll_update_events(rb_fde_t *, short, PF *);
static void devpoll_write_update(int, int);


int
rb_setup_fd_devpoll(rb_fde_t *F)
{
    return 0;
}


/*
 * Write an update to the devpoll filter.
 * See, we end up having to do a seperate (?) remove before we do an
 * add of a new polltype, so we have to have this function seperate from
 * the others.
 */
static void
devpoll_write_update(int fd, int events)
{
    struct pollfd pollfds[1];	/* Just to be careful */
    int retval;

    /* Build the pollfd entry */
    pollfds[0].revents = 0;
    pollfds[0].fd = fd;
    pollfds[0].events = events;

    /* Write the thing to our poll fd */
    retval = write(dpfd, &pollfds[0], sizeof(struct pollfd));
    if(retval != sizeof(struct pollfd))
        rb_lib_log("devpoll_write_update: dpfd write failed %d: %s", errno,
                   strerror(errno));
    /* Done! */
}

static void
devpoll_update_events(rb_fde_t *F, short filter, PF * handler)
{
    int update_required = 0;
    int fd = rb_get_fd(F);
    int cur_mask = fdmask[fd];
    PF *cur_handler;
    fdmask[fd] = 0;
    switch (filter) {
    case RB_SELECT_READ:
        cur_handler = F->read_handler;
        if(handler)
            fdmask[fd] |= POLLRDNORM;
        else
            fdmask[fd] &= ~POLLRDNORM;
        if(F->write_handler)
            fdmask[fd] |= POLLWRNORM;
        break;
    case RB_SELECT_WRITE:
        cur_handler = F->write_handler;
        if(handler)
            fdmask[fd] |= POLLWRNORM;
        else
            fdmask[fd] &= ~POLLWRNORM;
        if(F->read_handler)
            fdmask[fd] |= POLLRDNORM;
        break;
    default:
        return;
        break;
    }

    if(cur_handler == NULL && handler != NULL)
        update_required++;
    else if(cur_handler != NULL && handler == NULL)
        update_required++;
    if(cur_mask != fdmask[fd])
        update_required++;
    if(update_required) {
        /*
         * Ok, we can call devpoll_write_update() here now to re-build the
         * fd struct. If we end up with nothing on this fd, it won't write
         * anything.
         */
        if(fdmask[fd]) {
            devpoll_write_update(fd, POLLREMOVE);
            devpoll_write_update(fd, fdmask[fd]);
        } else
            devpoll_write_update(fd, POLLREMOVE);
    }
}





/* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
/* Public functions */


/*
 * rb_init_netio
 *
 * This is a needed exported function which will be called to initialise
 * the network loop code.
 */
int
rb_init_netio_devpoll(void)
{
    dpfd = open("/dev/poll", O_RDWR);
    if(dpfd < 0) {
        return errno;
    }
    maxfd = getdtablesize() - 2;	/* This makes more sense than HARD_FDLIMIT */
    fdmask = rb_malloc(sizeof(fdmask) * maxfd + 1);
    rb_open(dpfd, RB_FD_UNKNOWN, "/dev/poll file descriptor");
    return 0;
}

/*
 * rb_setselect
 *
 * This is a needed exported function which will be called to register
 * and deregister interest in a pending IO state for a given FD.
 */
void
rb_setselect_devpoll(rb_fde_t *F, unsigned int type, PF * handler, void *client_data)
{
    lrb_assert(IsFDOpen(F));

    if(type & RB_SELECT_READ) {
        devpoll_update_events(F, RB_SELECT_READ, handler);
        F->read_handler = handler;
        F->read_data = client_data;
    }
    if(type & RB_SELECT_WRITE) {
        devpoll_update_events(F, RB_SELECT_WRITE, handler);
        F->write_handler = handler;
        F->write_data = client_data;
    }
}

/*
 * Check all connections for new connections and input data that is to be
 * processed. Also check for connections with data queued and whether we can
 * write it out.
 */

/*
 * rb_select
 *
 * Called to do the new-style IO, courtesy of squid (like most of this
 * new IO code). This routine handles the stuff we've hidden in
 * rb_setselect and fd_table[] and calls callbacks for IO ready
 * events.
 */

int
rb_select_devpoll(long delay)
{
    int num, i;
    struct pollfd pollfds[maxfd];
    struct dvpoll dopoll;

    do {
        for(;;) {
            dopoll.dp_timeout = delay;
            dopoll.dp_nfds = maxfd;
            dopoll.dp_fds = &pollfds[0];
            num = ioctl(dpfd, DP_POLL, &dopoll);
            if(num >= 0)
                break;
            if(rb_ignore_errno(errno))
                break;
            rb_set_time();
            return RB_ERROR;
        }

        rb_set_time();
        if(num == 0)
            continue;

        for(i = 0; i < num; i++) {
            int fd = dopoll.dp_fds[i].fd;
            PF *hdl = NULL;
            rb_fde_t *F = rb_find_fd(fd);
            if((dopoll.dp_fds[i].revents & (POLLRDNORM | POLLIN | POLLHUP |
                                            POLLERR))
               && (dopoll.dp_fds[i].events & (POLLRDNORM | POLLIN))) {
                if((hdl = F->read_handler) != NULL) {
                    F->read_handler = NULL;
                    hdl(F, F->read_data);
                    /*
                     * this call used to be with a NULL pointer, BUT
                     * in the devpoll case we only want to update the
                     * poll set *if* the handler changes state (active ->
                     * NULL or vice versa.)
                     */
                    devpoll_update_events(F, RB_SELECT_READ, F->read_handler);
                }
            }

            if(!IsFDOpen(F))
                continue;	/* Read handler closed us..go on to do something more useful */
            if((dopoll.dp_fds[i].revents & (POLLWRNORM | POLLOUT | POLLHUP |
                                            POLLERR))
               && (dopoll.dp_fds[i].events & (POLLWRNORM | POLLOUT))) {
                if((hdl = F->write_handler) != NULL) {
                    F->write_handler = NULL;
                    hdl(F, F->write_data);
                    /* See above similar code in the read case */
                    devpoll_update_events(F,
                                          RB_SELECT_WRITE, F->write_handler);
                }

            }
        }
        return RB_OK;
    } while(0);
    /* XXX Get here, we broke! */
    return 0;
}

#else /* /dev/poll not supported */
int
rb_init_netio_devpoll(void)
{
    return ENOSYS;
}

void
rb_setselect_devpoll(rb_fde_t *F, unsigned int type, PF * handler, void *client_data)
{
    errno = ENOSYS;
    return;
}

int
rb_select_devpoll(long delay)
{
    errno = ENOSYS;
    return -1;
}

int
rb_setup_fd_devpoll(rb_fde_t *F)
{
    errno = ENOSYS;
    return -1;
}
#endif