11111

]int	selwait, nselcoll;

/*
* Select system call.
*/
struct select_args {
u_int	nd;
fd_set	*in, *ou, *ex;
struct	timeval *tv;
};
select(p, uap, retval)
register struct proc *p;
register struct select_args *uap;
int *retval;
{
fd_set ibits[3], obits[3];
struct timeval atv;
int s, ncoll, error = 0, timo;
u_int ni;

bzero((caddr_t)ibits, sizeof(ibits));
bzero((caddr_t)obits, sizeof(obits));
if (uap->nd > FD_SETSIZE)
return (EINVAL);
if (uap->nd > p->p_fd->fd_nfiles)
uap->nd = p->p_fd->fd_nfiles;	/* forgiving; slightly wrong */
ni = howmany(uap->nd, NFDBITS) * sizeof(fd_mask);

#define	getbits(name, x) /
if (uap->name && /
(error = copyin((caddr_t)uap->name, (caddr_t)&ibits[x], ni))) /
goto done;
getbits(in, 0);
getbits(ou, 1);
getbits(ex, 2);
#undef	getbits

if (uap->tv) {
error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
sizeof (atv));
if (error)
goto done;
if (itimerfix(&atv)) {
error = EINVAL;
goto done;
}
s = splclock();
timevaladd(&atv, (struct timeval *)&time);
timo = hzto(&atv);
/*
* Avoid inadvertently sleeping forever.
*/
if (timo == 0)
timo = 1;
splx(s);
} else
timo = 0;
retry:
ncoll = nselcoll;
p->p_flag |= P_SELECT;
error = selscan(p, ibits, obits, uap->nd, retval);
if (error || *retval)
goto done;
s = splhigh();
/* this should be timercmp(&time, &atv, >=) */
if (uap->tv && (time.tv_sec > atv.tv_sec ||
time.tv_sec == atv.tv_sec && time.tv_usec >= atv.tv_usec)) {
splx(s);
goto done;
}
if ((p->p_flag & P_SELECT) == 0 || nselcoll != ncoll) {
splx(s);
goto retry;
}
p->p_flag &= ~P_SELECT;
error = tsleep((caddr_t)&selwait, PSOCK | PCATCH, "select", timo);
splx(s);
if (error == 0)
goto retry;
done:
p->p_flag &= ~P_SELECT;
/* select is not restarted after signals... */
if (error == ERESTART)
error = EINTR;
if (error == EWOULDBLOCK)
error = 0;
#define	putbits(name, x) /
if (uap->name && /
(error2 = copyout((caddr_t)&obits[x], (caddr_t)uap->name, ni))) /
error = error2;
if (error == 0) {
int error2;

putbits(in, 0);
putbits(ou, 1);
putbits(ex, 2);
#undef putbits
}
return (error);