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/*

 *  $Id: rtems_select.c,v 1.2 2001-09-27 12:02:00 chris Exp $

 */

#include <string.h>

#include <stdarg.h>

/* #include <stdlib.h> */

#include <stdio.h>

#include <rtems.h>

#include <rtems/libio.h>

#include <rtems/error.h>

#include <rtems/rtems_bsdnet.h>

#include <sys/errno.h>

#include <sys/fcntl.h>

#include <sys/types.h>

#include <sys/param.h>

#include <sys/mbuf.h>

#include <sys/socket.h>

#include <sys/socketvar.h>

#include <sys/protosw.h>

#include <sys/proc.h>

#include <sys/filio.h>

#include <net/if.h>

#include <net/route.h>

/*

 *********************************************************************

 *            RTEMS implementation of select() system call           *

 *********************************************************************

 */

/*

 * This implementation is quite restricted:

 *      Works on sockets only -- no support for other devices!

 *      A given socket can be in a read-select or a read/recv* by only

 *              one task at a time.

 *      A given socket can be in a write-select or a write/send* by only

 *              one task at a time.

 *

 * NOTE - select() is a very expensive system call.  It should be avoided

 *        if at all possible.  In many cases, rewriting the application

 *        to use multiple tasks (one per socket) is a better solution.

 */

static __inline int imin(int a, int b) { return (a < b ? a : b); }

struct socket *rtems_bsdnet_fdToSocket(int fd);

static int

socket_select (struct socket *so, int which, rtems_id tid)

{

        switch (which) {

        case FREAD:

                if (soreadable(so))

                        return (1);

                so->so_rcv.sb_flags |= SB_WAIT;

                so->so_rcv.sb_sel.si_pid = tid;

                break;

        case FWRITE:

                if (sowriteable(so))

                        return (1);

                so->so_rcv.sb_flags |= SB_WAIT;

                so->so_snd.sb_sel.si_pid = tid;

                break;

        case 0:

                if (so->so_oobmark || (so->so_state & SS_RCVATMARK))

                        return (1);

                so->so_rcv.sb_sel.si_pid = tid;

                break;

        }

        return (0);

}

static int

selscan (rtems_id tid, fd_mask **ibits, fd_mask **obits, int nfd, int *retval)

{

        struct socket *so;

        int msk, i, fd;

        fd_mask bits, bit;

        int n = 0;

        static int flag[3] = { FREAD, FWRITE, 0 };

        for (msk = 0; msk < 3; msk++) {

                if (ibits[msk] == NULL)

                        continue;

                for (i = 0; i < nfd; i += NFDBITS) {

                        bits = ibits[msk][i/NFDBITS];

                        for (fd = i, bit = 1 ; bits && (fd < nfd) ; fd++, bit <<= 1) {

                                if ((bits & bit) == 0)

                                        continue;

                                bits &= ~bit;

                                so = rtems_bsdnet_fdToSocket (fd);

                                if (so == NULL)

                                        return (EBADF);

                                if (socket_select (so, flag[msk], tid)) {

                                        obits[msk][fd/NFDBITS] |=

                                                        (1 << (fd % NFDBITS));

                                        n++;

                                }

                        }

                }

        }

        *retval = n;

        return (0);

}

int

select (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *tv)

{

        fd_mask *ibits[3], *obits[3];

        fd_set ob[3];

        int error, timo;

        int retval;

        rtems_id tid;

        rtems_interval then, now;

        rtems_event_set events;

        if (nfds < 0)

                return (EINVAL);

        if (tv) {

                timo = tv->tv_sec * hz + tv->tv_usec / tick;

                if (timo == 0)

                        timo = 1;

                rtems_clock_get (RTEMS_CLOCK_GET_TICKS_SINCE_BOOT, &then);

        }

        else {

                timo = 0;

        }

#define getbits(name,i) if (name) { \

                ibits[i] = &name->fds_bits[0]; \

                obits[i] = &ob[i].fds_bits[0]; \

                FD_ZERO(&ob[i]); \

        } \

        else ibits[i] = NULL

        getbits (readfds, 0);

        getbits (writefds, 1);

        getbits (exceptfds, 2);

#undef getbits

        rtems_task_ident (RTEMS_SELF, 0, &tid);

        rtems_event_receive (SBWAIT_EVENT, RTEMS_EVENT_ANY | RTEMS_NO_WAIT, RTEMS_NO_TIMEOUT, &events);

        for (;;) {

                rtems_bsdnet_semaphore_obtain ();

                error = selscan(tid, ibits, obits, nfds, &retval);

                rtems_bsdnet_semaphore_release ();

                if (error || retval)

                        break;

                if (timo) {

                        rtems_clock_get (RTEMS_CLOCK_GET_TICKS_SINCE_BOOT, &now);

                        timo -= now - then;

                        if (timo <= 0)

                                break;

                        then = now;

                }

                rtems_event_receive (SBWAIT_EVENT, RTEMS_EVENT_ANY | RTEMS_WAIT, timo, &events);

        }

#define putbits(name,i) if (name) *name = ob[i]

        putbits (readfds, 0);

        putbits (writefds, 1);

        putbits (exceptfds, 2);

#undef putbits

        if (error) {

                errno = error;

                retval = -1;

        }

        return (retval);

}