/*
* User-level interface: read, poll.
* (User cannot write an event queue.)
*/
int
wsevent_read(struct wseventvar *ev, struct uio *uio, int flags)
{
int s, error;
u_int cnt;
size_t n;
/*
* Make sure we can return at least 1.
*/
if (uio->uio_resid < sizeof(struct wscons_event))
return (EMSGSIZE); /* ??? */
s = splwsevent();
while (ev->get == ev->put) {
if (flags & IO_NDELAY) {
splx(s);
return (EWOULDBLOCK);
}
ev->wanted = 1;
error = tsleep(ev, PWSEVENT | PCATCH,
"wsevent_read", 0);
if (error) {
splx(s);
return (error);
}
}
/*
* Move wscons_event from tail end of queue (there is at least one
* there).
*/
if (ev->put < ev->get)
cnt = WSEVENT_QSIZE - ev->get; /* events in [get..QSIZE) */
else
cnt = ev->put - ev->get; /* events in [get..put) */
splx(s);
n = howmany(uio->uio_resid, sizeof(struct wscons_event));
if (cnt > n)
cnt = n;
error = uiomove((caddr_t)&ev->q[ev->get],
cnt * sizeof(struct wscons_event), uio);
n -= cnt;
/*
* If we do not wrap to 0, used up all our space, or had an error,
* stop. Otherwise move from front of queue to put index, if there
* is anything there to move.
*/
if ((ev->get = (ev->get + cnt) % WSEVENT_QSIZE) != 0 ||
n == 0 || error || (cnt = ev->put) == 0)
return (error);
if (cnt > n)
cnt = n;
error = uiomove((caddr_t)&ev->q[0],
cnt * sizeof(struct wscons_event), uio);
ev->get = cnt;
return (error);
}
void
filt_wseventdetach(struct knote *kn)
{
struct wseventvar *ev = kn->kn_hook;
struct klist *klist = &ev->sel.si_note;
int s;
s = splwsevent();
SLIST_REMOVE(klist, kn, knote, kn_selnext);
splx(s);
}
int
wsevent_poll(struct wseventvar *ev, int events, struct proc *p)
{
int revents = 0;
int s = splwsevent();
if (events & (POLLIN | POLLRDNORM)) {
if (ev->get != ev->put)
revents |= events & (POLLIN | POLLRDNORM);
else
selrecord(p, &ev->sel);
}
splx(s);
return (revents);
}
int
wsevent_kqfilter(struct wseventvar *ev, struct knote *kn)
{
struct klist *klist;
int s;
klist = &ev->sel.si_note;
switch (kn->kn_filter) {
case EVFILT_READ:
kn->kn_fop = &wsevent_filtops;
break;
default:
return (EINVAL);
}
kn->kn_hook = ev;
s = splwsevent();
SLIST_INSERT_HEAD(klist, kn, kn_selnext);
splx(s);
return (0);
}
