kern_return_t
ipc_object_copyout(
ipc_space_t space,
ipc_object_t object,
mach_msg_type_name_t msgt_name,
boolean_t overflow,
mach_port_name_t *namep)
{
mach_port_name_t name;
ipc_entry_t entry;
kern_return_t kr;
assert(IO_VALID(object));
assert(io_otype(object) == IOT_PORT);
is_write_lock(space);
for (;;) {
if (!is_active(space)) {
is_write_unlock(space);
return KERN_INVALID_TASK;
}
if ((msgt_name != MACH_MSG_TYPE_PORT_SEND_ONCE) &&
ipc_right_reverse(space, object, &name, &entry)) {
/* object is locked and active */
assert(entry->ie_bits & MACH_PORT_TYPE_SEND_RECEIVE);
break;
}
name = CAST_MACH_PORT_TO_NAME(object);
kr = ipc_entry_get(space, &name, &entry);
if (kr != KERN_SUCCESS) {
/* unlocks/locks space, so must start again */
kr = ipc_entry_grow_table(space, ITS_SIZE_NONE);
if (kr != KERN_SUCCESS)
return kr; /* space is unlocked */
continue;
}
assert(IE_BITS_TYPE(entry->ie_bits) == MACH_PORT_TYPE_NONE);
assert(entry->ie_object == IO_NULL);
io_lock(object);
if (!io_active(object)) {
io_unlock(object);
ipc_entry_dealloc(space, name, entry);
is_write_unlock(space);
return KERN_INVALID_CAPABILITY;
}
entry->ie_object = object;
break;
}
/* space is write-locked and active, object is locked and active */
kr = ipc_right_copyout(space, name, entry,
msgt_name, overflow, object);
/* object is unlocked */
is_write_unlock(space);
if (kr == KERN_SUCCESS)
*namep = name;
return kr;
}
void
exception_raise(
ipc_port_t dest_port,
ipc_port_t thread_port,
ipc_port_t task_port,
integer_t _exception,
integer_t code,
integer_t subcode)
{
ipc_thread_t self = current_thread();
ipc_thread_t receiver;
ipc_port_t reply_port;
ipc_mqueue_t dest_mqueue;
ipc_mqueue_t reply_mqueue;
ipc_kmsg_t kmsg;
mach_msg_return_t mr;
assert(IP_VALID(dest_port));
/*
* We will eventually need a message buffer.
* Grab the buffer now, while nothing is locked.
* This buffer will get handed to the exception server,
* and it will give the buffer back with its reply.
*/
kmsg = ikm_cache();
if (kmsg != IKM_NULL) {
ikm_cache() = IKM_NULL;
ikm_check_initialized(kmsg, IKM_SAVED_KMSG_SIZE);
} else {
kmsg = ikm_alloc(IKM_SAVED_MSG_SIZE);
if (kmsg == IKM_NULL)
panic("exception_raise");
ikm_init(kmsg, IKM_SAVED_MSG_SIZE);
}
/*
* We need a reply port for the RPC.
* Check first for a cached port.
*/
ith_lock(self);
assert(self->ith_self != IP_NULL);
reply_port = self->ith_rpc_reply;
if (reply_port == IP_NULL) {
ith_unlock(self);
reply_port = ipc_port_alloc_reply();
ith_lock(self);
if ((reply_port == IP_NULL) ||
(self->ith_rpc_reply != IP_NULL))
panic("exception_raise");
self->ith_rpc_reply = reply_port;
}
ip_lock(reply_port);
assert(ip_active(reply_port));
ith_unlock(self);
/*
* Make a naked send-once right for the reply port,
* to hand to the exception server.
* Make an extra reference for the reply port,
* to receive on. This protects us against
* mach_msg_abort_rpc.
*/
reply_port->ip_sorights++;
ip_reference(reply_port);
ip_reference(reply_port);
self->ith_port = reply_port;
reply_mqueue = &reply_port->ip_messages;
imq_lock(reply_mqueue);
assert(ipc_kmsg_queue_empty(&reply_mqueue->imq_messages));
ip_unlock(reply_port);
/*
* Make sure we can queue to the destination port.
*/
if (!ip_lock_try(dest_port)) {
imq_unlock(reply_mqueue);
goto slow_exception_raise;
}
if (!ip_active(dest_port) ||
(dest_port->ip_receiver == ipc_space_kernel)) {
imq_unlock(reply_mqueue);
ip_unlock(dest_port);
goto slow_exception_raise;
}
/*
* Find the destination message queue.
*/
{
ipc_pset_t dest_pset;
dest_pset = dest_port->ip_pset;
if (dest_pset == IPS_NULL)
dest_mqueue = &dest_port->ip_messages;
else
dest_mqueue = &dest_pset->ips_messages;
}
if (!imq_lock_try(dest_mqueue)) {
imq_unlock(reply_mqueue);
ip_unlock(dest_port);
goto slow_exception_raise;
}
/*
* Safe to unlock dest_port, because we hold
* dest_mqueue locked. We never bother changing
* dest_port->ip_msgcount.
*/
ip_unlock(dest_port);
receiver = ipc_thread_queue_first(&dest_mqueue->imq_threads);
if ((receiver == ITH_NULL) ||
!((receiver->swap_func == (void (*)()) mach_msg_continue) ||
((receiver->swap_func ==
(void (*)()) mach_msg_receive_continue) &&
(sizeof(struct mach_exception) <= receiver->ith_msize) &&
((receiver->ith_option & MACH_RCV_NOTIFY) == 0))) ||
!thread_handoff(self, exception_raise_continue, receiver)) {
imq_unlock(reply_mqueue);
imq_unlock(dest_mqueue);
goto slow_exception_raise;
}
counter(c_exception_raise_block++);
assert(current_thread() == receiver);
/*
* We need to finish preparing self for its
* time asleep in reply_mqueue. self is left
* holding the extra ref for reply_port.
*/
ipc_thread_enqueue_macro(&reply_mqueue->imq_threads, self);
self->ith_state = MACH_RCV_IN_PROGRESS;
self->ith_msize = MACH_MSG_SIZE_MAX;
imq_unlock(reply_mqueue);
/*
* Finish extracting receiver from dest_mqueue.
*/
ipc_thread_rmqueue_first_macro(
&dest_mqueue->imq_threads, receiver);
imq_unlock(dest_mqueue);
/*
* Release the receiver's reference for his object.
*/
{
ipc_object_t object = receiver->ith_object;
io_lock(object);
io_release(object);
io_check_unlock(object);
}
{
struct mach_exception *exc =
(struct mach_exception *) &kmsg->ikm_header;
ipc_space_t space = receiver->task->itk_space;
/*
* We are running as the receiver now. We hold
* the following resources, which must be consumed:
* kmsg, send-once right for reply_port
* send rights for dest_port, thread_port, task_port
* Synthesize a kmsg for copyout to the receiver.
*/
exc->Head.msgh_bits = (MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND_ONCE,
MACH_MSG_TYPE_PORT_SEND) |
MACH_MSGH_BITS_COMPLEX);
exc->Head.msgh_size = sizeof *exc;
/* exc->Head.msgh_remote_port later */
/* exc->Head.msgh_local_port later */
exc->Head.msgh_seqno = 0;
exc->Head.msgh_id = MACH_EXCEPTION_ID;
exc->threadType = exc_port_proto;
/* exc->thread later */
exc->taskType = exc_port_proto;
/* exc->task later */
exc->exceptionType = exc_code_proto;
exc->exception = _exception;
exc->codeType = exc_code_proto;
exc->code = code;
exc->subcodeType = exc_code_proto;
exc->subcode = subcode;
/*
* Check that the receiver can handle the message.
*/
if (receiver->ith_rcv_size < sizeof(struct mach_exception)) {
/*
* ipc_kmsg_destroy is a handy way to consume
* the resources we hold, but it requires setup.
*/
exc->Head.msgh_bits =
(MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND,
MACH_MSG_TYPE_PORT_SEND_ONCE) |
MACH_MSGH_BITS_COMPLEX);
exc->Head.msgh_remote_port = (mach_port_t) dest_port;
exc->Head.msgh_local_port = (mach_port_t) reply_port;
exc->thread = (mach_port_t) thread_port;
exc->task = (mach_port_t) task_port;
ipc_kmsg_destroy(kmsg);
thread_syscall_return(MACH_RCV_TOO_LARGE);
/*NOTREACHED*/
}
is_write_lock(space);
assert(space->is_active);
/*
* To do an atomic copyout, need simultaneous
* locks on both ports and the space.
*/
ip_lock(dest_port);
if (!ip_active(dest_port) ||
!ip_lock_try(reply_port)) {
abort_copyout:
ip_unlock(dest_port);
is_write_unlock(space);
/*
* Oh well, we have to do the header the slow way.
* First make it look like it's in-transit.
*/
exc->Head.msgh_bits =
(MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND,
MACH_MSG_TYPE_PORT_SEND_ONCE) |
MACH_MSGH_BITS_COMPLEX);
exc->Head.msgh_remote_port = (mach_port_t) dest_port;
exc->Head.msgh_local_port = (mach_port_t) reply_port;
mr = ipc_kmsg_copyout_header(&exc->Head, space,
MACH_PORT_NULL);
if (mr == MACH_MSG_SUCCESS)
goto copyout_body;
/*
* Ack! Prepare for ipc_kmsg_copyout_dest.
* It will consume thread_port and task_port.
*/
exc->thread = (mach_port_t) thread_port;
exc->task = (mach_port_t) task_port;
ipc_kmsg_copyout_dest(kmsg, space);
(void) ipc_kmsg_put(receiver->ith_msg, kmsg,
sizeof(mach_msg_header_t));
thread_syscall_return(mr);
/*NOTREACHED*/
}
if (!ip_active(reply_port)) {
ip_unlock(reply_port);
goto abort_copyout;
}
assert(reply_port->ip_sorights > 0);
ip_unlock(reply_port);
{
kern_return_t kr;
ipc_entry_t entry;
kr = ipc_entry_get (space, &exc->Head.msgh_remote_port, &entry);
if (kr)
goto abort_copyout;
{
mach_port_gen_t gen;
assert((entry->ie_bits &~ IE_BITS_GEN_MASK) == 0);
gen = entry->ie_bits + IE_BITS_GEN_ONE;
/* optimized ipc_right_copyout */
entry->ie_bits = gen | (MACH_PORT_TYPE_SEND_ONCE | 1);
}
entry->ie_object = (ipc_object_t) reply_port;
is_write_unlock(space);
}
/* optimized ipc_object_copyout_dest */
assert(dest_port->ip_srights > 0);
ip_release(dest_port);
exc->Head.msgh_local_port =
((dest_port->ip_receiver == space) ?
dest_port->ip_receiver_name : MACH_PORT_NULL);
if ((--dest_port->ip_srights == 0) &&
(dest_port->ip_nsrequest != IP_NULL)) {
ipc_port_t nsrequest;
mach_port_mscount_t mscount;
/* a rather rare case */
nsrequest = dest_port->ip_nsrequest;
mscount = dest_port->ip_mscount;
dest_port->ip_nsrequest = IP_NULL;
ip_unlock(dest_port);
ipc_notify_no_senders(nsrequest, mscount);
} else
ip_unlock(dest_port);
copyout_body:
/*
* Optimized version of ipc_kmsg_copyout_body,
* to handle the two ports in the body.
*/
mr = (ipc_kmsg_copyout_object(space, (ipc_object_t) thread_port,
MACH_MSG_TYPE_PORT_SEND, &exc->thread) |
ipc_kmsg_copyout_object(space, (ipc_object_t) task_port,
MACH_MSG_TYPE_PORT_SEND, &exc->task));
if (mr != MACH_MSG_SUCCESS) {
(void) ipc_kmsg_put(receiver->ith_msg, kmsg,
kmsg->ikm_header.msgh_size);
thread_syscall_return(mr | MACH_RCV_BODY_ERROR);
/*NOTREACHED*/
}
}
/*
* Optimized version of ipc_kmsg_put.
* We must check ikm_cache after copyoutmsg.
*/
ikm_check_initialized(kmsg, kmsg->ikm_size);
assert(kmsg->ikm_size == IKM_SAVED_KMSG_SIZE);
if (copyoutmsg(&kmsg->ikm_header, receiver->ith_msg,
sizeof(struct mach_exception)) ||
(ikm_cache() != IKM_NULL)) {
mr = ipc_kmsg_put(receiver->ith_msg, kmsg,
kmsg->ikm_header.msgh_size);
thread_syscall_return(mr);
/*NOTREACHED*/
}
ikm_cache() = kmsg;
thread_syscall_return(MACH_MSG_SUCCESS);
/*NOTREACHED*/
#ifndef __GNUC__
return; /* help for the compiler */
#endif
slow_exception_raise: {
struct mach_exception *exc =
(struct mach_exception *) &kmsg->ikm_header;
ipc_kmsg_t reply_kmsg;
mach_port_seqno_t reply_seqno;
exception_raise_misses++;
/*
* We hold the following resources, which must be consumed:
* kmsg, send-once right and ref for reply_port
* send rights for dest_port, thread_port, task_port
* Synthesize a kmsg to send.
*/
exc->Head.msgh_bits = (MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND,
MACH_MSG_TYPE_PORT_SEND_ONCE) |
MACH_MSGH_BITS_COMPLEX);
exc->Head.msgh_size = sizeof *exc;
exc->Head.msgh_remote_port = (mach_port_t) dest_port;
exc->Head.msgh_local_port = (mach_port_t) reply_port;
exc->Head.msgh_seqno = 0;
exc->Head.msgh_id = MACH_EXCEPTION_ID;
exc->threadType = exc_port_proto;
exc->thread = (mach_port_t) thread_port;
exc->taskType = exc_port_proto;
exc->task = (mach_port_t) task_port;
exc->exceptionType = exc_code_proto;
exc->exception = _exception;
exc->codeType = exc_code_proto;
exc->code = code;
exc->subcodeType = exc_code_proto;
exc->subcode = subcode;
ipc_mqueue_send_always(kmsg);
/*
* We are left with a ref for reply_port,
* which we use to receive the reply message.
*/
ip_lock(reply_port);
if (!ip_active(reply_port)) {
ip_unlock(reply_port);
exception_raise_continue_slow(MACH_RCV_PORT_DIED, IKM_NULL, /*dummy*/0);
/*NOTREACHED*/
}
imq_lock(reply_mqueue);
ip_unlock(reply_port);
mr = ipc_mqueue_receive(reply_mqueue, MACH_MSG_OPTION_NONE,
MACH_MSG_SIZE_MAX,
MACH_MSG_TIMEOUT_NONE,
FALSE, exception_raise_continue,
&reply_kmsg, &reply_seqno);
/* reply_mqueue is unlocked */
exception_raise_continue_slow(mr, reply_kmsg, reply_seqno);
/*NOTREACHED*/
}
}
