soc_select.c

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#include "soc_common.h"
#include <errno.h>
#include <poll.h>
#include <stdlib.h>
#include <sys/select.h>

int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
{
    struct pollfd *pollinfo;
    nfds_t numfds = 0;
    size_t i, j;
    int rc, found;

    for(i = 0; i < nfds; ++i) {
        if((readfds && FD_ISSET(i, readfds))
        || (writefds && FD_ISSET(i, writefds))
        || (exceptfds && FD_ISSET(i, exceptfds)))
            ++numfds;
    }

    pollinfo = (struct pollfd*)calloc(numfds, sizeof(struct pollfd));
    if(pollinfo == NULL) {
        SOCU_errno = ENOMEM;
        return -1;
    }

    for(i = 0, j = 0; i < nfds; ++i) {
        if((readfds && FD_ISSET(i, readfds))
        || (writefds && FD_ISSET(i, writefds))
        || (exceptfds && FD_ISSET(i, exceptfds))) {
            pollinfo[j].fd      = i;
            pollinfo[j].events  = 0;
            pollinfo[j].revents = 0;

            if(readfds && FD_ISSET(i, readfds))
                pollinfo[j].events |= POLLIN;
            if(writefds && FD_ISSET(i, writefds))
                pollinfo[j].events |= POLLOUT;

            ++j;
        }
    }

    if(timeout)
        rc = poll(pollinfo, numfds, timeout->tv_sec*1000 + timeout->tv_usec/1000);
    else
        rc = poll(pollinfo, numfds, -1);

    if(rc < 0) {
        free(pollinfo);
        return rc;
    }

    for(i = 0, j = 0, rc = 0; i < nfds; ++i) {
        found = 0;

        if((readfds && FD_ISSET(i, readfds))
        || (writefds && FD_ISSET(i, writefds))
        || (exceptfds && FD_ISSET(i, exceptfds))) {

            if(readfds && FD_ISSET(i, readfds)) {
                if(pollinfo[j].events & (POLLIN|POLLHUP))
                    found = 1;
                else
                    FD_CLR(i, readfds);
            }

            if(writefds && FD_ISSET(i, writefds)) {
                if(pollinfo[j].events & (POLLOUT|POLLHUP))
                    found = 1;
                else
                    FD_CLR(i, writefds);
            }

            if(exceptfds && FD_ISSET(i, exceptfds)) {
                if(pollinfo[j].events & POLLERR)
                    found = 1;
                else
                    FD_CLR(i, exceptfds);
            }

            if(found) ++rc;
            ++j;
        }
    }

    free(pollinfo);

    return rc;
}