void
ipc_mqueue_receive(
ipc_mqueue_t mqueue,
mach_msg_option_t option,
mach_msg_size_t max_size,
mach_msg_timeout_t rcv_timeout,
int interruptible)
{
wait_result_t wresult;
thread_t self = current_thread();
wresult = ipc_mqueue_receive_on_thread(mqueue, option, max_size,
rcv_timeout, interruptible,
self);
if (wresult == THREAD_NOT_WAITING)
return;
if (wresult == THREAD_WAITING) {
counter((interruptible == THREAD_ABORTSAFE) ?
c_ipc_mqueue_receive_block_user++ :
c_ipc_mqueue_receive_block_kernel++);
if (self->ith_continuation)
thread_block(ipc_mqueue_receive_continue);
/* NOTREACHED */
wresult = thread_block(THREAD_CONTINUE_NULL);
}
ipc_mqueue_receive_results(wresult);
}
static int
filt_machport(
struct knote *kn,
__unused long hint)
{
mach_port_name_t name = (mach_port_name_t)kn->kn_kevent.ident;
ipc_pset_t pset = IPS_NULL;
wait_result_t wresult;
thread_t self = current_thread();
kern_return_t kr;
mach_msg_option_t option;
mach_msg_size_t size;
/* never called from below */
assert(hint == 0);
/*
* called from user context. Have to validate the
* name. If it changed, we have an EOF situation.
*/
kr = ipc_object_translate(current_space(), name,
MACH_PORT_RIGHT_PORT_SET,
(ipc_object_t *)&pset);
if (kr != KERN_SUCCESS || pset != kn->kn_ptr.p_pset || !ips_active(pset)) {
kn->kn_data = 0;
kn->kn_flags |= (EV_EOF | EV_ONESHOT);
if (pset != IPS_NULL) {
ips_unlock(pset);
}
return(1);
}
/* just use the reference from here on out */
ips_reference(pset);
ips_unlock(pset);
/*
* Only honor supported receive options. If no options are
* provided, just force a MACH_RCV_TOO_LARGE to detect the
* name of the port and sizeof the waiting message.
*/
option = kn->kn_sfflags & (MACH_RCV_MSG|MACH_RCV_LARGE|MACH_RCV_LARGE_IDENTITY|
MACH_RCV_TRAILER_MASK|MACH_RCV_VOUCHER);
if (option & MACH_RCV_MSG) {
self->ith_msg_addr = (mach_vm_address_t) kn->kn_ext[0];
size = (mach_msg_size_t)kn->kn_ext[1];
} else {
option = MACH_RCV_LARGE;
self->ith_msg_addr = 0;
size = 0;
}
/*
* Set up to receive a message or the notification of a
* too large message. But never allow this call to wait.
* If the user provided aditional options, like trailer
* options, pass those through here. But we don't support
* scatter lists through this interface.
*/
self->ith_object = (ipc_object_t)pset;
self->ith_msize = size;
self->ith_option = option;
self->ith_receiver_name = MACH_PORT_NULL;
self->ith_continuation = NULL;
option |= MACH_RCV_TIMEOUT; // never wait
self->ith_state = MACH_RCV_IN_PROGRESS;
wresult = ipc_mqueue_receive_on_thread(
&pset->ips_messages,
option,
size, /* max_size */
0, /* immediate timeout */
THREAD_INTERRUPTIBLE,
self);
assert(wresult == THREAD_NOT_WAITING);
assert(self->ith_state != MACH_RCV_IN_PROGRESS);
/*
* If we timed out, just release the reference on the
* portset and return zero.
*/
if (self->ith_state == MACH_RCV_TIMED_OUT) {
ips_release(pset);
return 0;
}
/*
* If we weren't attempting to receive a message
* directly, we need to return the port name in
* the kevent structure.
*/
if ((option & MACH_RCV_MSG) != MACH_RCV_MSG) {
assert(self->ith_state == MACH_RCV_TOO_LARGE);
assert(self->ith_kmsg == IKM_NULL);
kn->kn_data = self->ith_receiver_name;
ips_release(pset);
return 1;
}
/*
* Attempt to receive the message directly, returning
* the results in the fflags field.
*/
assert(option & MACH_RCV_MSG);
kn->kn_ext[1] = self->ith_msize;
kn->kn_data = MACH_PORT_NULL;
kn->kn_fflags = mach_msg_receive_results();
/* kmsg and pset reference consumed */
/*
* if the user asked for the identity of ports containing a
* a too-large message, return it in the data field (as we
* do for messages we didn't try to receive).
*/
if ((kn->kn_fflags == MACH_RCV_TOO_LARGE) &&
(option & MACH_RCV_LARGE_IDENTITY))
kn->kn_data = self->ith_receiver_name;
return 1;
}
