/* * Mach Operating System * Copyright (c) 1991,1990,1989 Carnegie Mellon University. * Copyright (c) 1993,1994 The University of Utah and * the Computer Systems Laboratory (CSL). * All rights reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON, THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF * THIS SOFTWARE IN ITS "AS IS" CONDITION, AND DISCLAIM ANY LIABILITY * OF ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF * THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ /* */ /* * File: ipc/mach_msg.c * Author: Rich Draves * Date: 1989 * * Exported message traps. See mach/message.h. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Routine: mach_msg_send * Purpose: * Send a message. * Conditions: * Nothing locked. * Returns: * MACH_MSG_SUCCESS Sent the message. * MACH_SEND_MSG_TOO_SMALL Message smaller than a header. * MACH_SEND_NO_BUFFER Couldn't allocate buffer. * MACH_SEND_INVALID_DATA Couldn't copy message data. * MACH_SEND_INVALID_HEADER * Illegal value in the message header bits. * MACH_SEND_INVALID_DEST The space is dead. * MACH_SEND_INVALID_NOTIFY Bad notify port. * MACH_SEND_INVALID_DEST Can't copyin destination port. * MACH_SEND_INVALID_REPLY Can't copyin reply port. * MACH_SEND_TIMED_OUT Timeout expired without delivery. * MACH_SEND_INTERRUPTED Delivery interrupted. * MACH_SEND_NO_NOTIFY Can't allocate a msg-accepted request. * MACH_SEND_WILL_NOTIFY Msg-accepted notif. requested. * MACH_SEND_NOTIFY_IN_PROGRESS * This space has already forced a message to this port. */ mach_msg_return_t mach_msg_send( mach_msg_header_t *msg, mach_msg_option_t option, mach_msg_size_t send_size, mach_msg_timeout_t time_out, mach_port_t notify) { ipc_space_t space = current_space(); vm_map_t map = current_map(); ipc_kmsg_t kmsg; mach_msg_return_t mr; mr = ipc_kmsg_get(msg, send_size, &kmsg); if (mr != MACH_MSG_SUCCESS) return mr; if (option & MACH_SEND_CANCEL) { if (notify == MACH_PORT_NULL) mr = MACH_SEND_INVALID_NOTIFY; else mr = ipc_kmsg_copyin(kmsg, space, map, notify); } else mr = ipc_kmsg_copyin(kmsg, space, map, MACH_PORT_NULL); if (mr != MACH_MSG_SUCCESS) { ikm_free(kmsg); return mr; } if (option & MACH_SEND_NOTIFY) { mr = ipc_mqueue_send(kmsg, MACH_SEND_TIMEOUT, ((option & MACH_SEND_TIMEOUT) ? time_out : MACH_MSG_TIMEOUT_NONE)); if (mr == MACH_SEND_TIMED_OUT) { ipc_port_t dest = (ipc_port_t) kmsg->ikm_header.msgh_remote_port; if (notify == MACH_PORT_NULL) mr = MACH_SEND_INVALID_NOTIFY; else mr = ipc_marequest_create(space, dest, notify, &kmsg->ikm_marequest); if (mr == MACH_MSG_SUCCESS) { ipc_mqueue_send_always(kmsg); return MACH_SEND_WILL_NOTIFY; } } } else mr = ipc_mqueue_send(kmsg, option & MACH_SEND_TIMEOUT, time_out); if (mr != MACH_MSG_SUCCESS) { mr |= ipc_kmsg_copyout_pseudo(kmsg, space, map); assert(kmsg->ikm_marequest == IMAR_NULL); (void) ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); } return mr; } /* * Routine: mach_msg_receive * Purpose: * Receive a message. * Conditions: * Nothing locked. * Returns: * MACH_MSG_SUCCESS Received a message. * MACH_RCV_INVALID_NAME The name doesn't denote a right, * or the denoted right is not receive or port set. * MACH_RCV_IN_SET Receive right is a member of a set. * MACH_RCV_TOO_LARGE Message wouldn't fit into buffer. * MACH_RCV_TIMED_OUT Timeout expired without a message. * MACH_RCV_INTERRUPTED Reception interrupted. * MACH_RCV_PORT_DIED Port/set died while receiving. * MACH_RCV_PORT_CHANGED Port moved into set while receiving. * MACH_RCV_INVALID_DATA Couldn't copy to user buffer. * MACH_RCV_INVALID_NOTIFY Bad notify port. * MACH_RCV_HEADER_ERROR */ mach_msg_return_t mach_msg_receive( mach_msg_header_t *msg, mach_msg_option_t option, mach_msg_size_t rcv_size, mach_port_t rcv_name, mach_msg_timeout_t time_out, mach_port_t notify) { ipc_thread_t self = current_thread(); ipc_space_t space = current_space(); vm_map_t map = current_map(); ipc_object_t object; ipc_mqueue_t mqueue; ipc_kmsg_t kmsg; mach_port_seqno_t seqno; mach_msg_return_t mr; mr = ipc_mqueue_copyin(space, rcv_name, &mqueue, &object); if (mr != MACH_MSG_SUCCESS) return mr; /* hold ref for object; mqueue is locked */ /* * ipc_mqueue_receive may not return, because if we block * then our kernel stack may be discarded. So we save * state here for mach_msg_receive_continue to pick up. */ self->ith_msg = msg; self->ith_option = option; self->ith_rcv_size = rcv_size; self->ith_timeout = time_out; self->ith_notify = notify; self->ith_object = object; self->ith_mqueue = mqueue; if (option & MACH_RCV_LARGE) { mr = ipc_mqueue_receive(mqueue, option & MACH_RCV_TIMEOUT, rcv_size, time_out, FALSE, mach_msg_receive_continue, &kmsg, &seqno); /* mqueue is unlocked */ ipc_object_release(object); if (mr != MACH_MSG_SUCCESS) { if (mr == MACH_RCV_TOO_LARGE) { mach_msg_size_t real_size = (mach_msg_size_t) (vm_offset_t) kmsg; assert(real_size > rcv_size); (void) copyout(&real_size, &msg->msgh_size, sizeof(mach_msg_size_t)); } return mr; } kmsg->ikm_header.msgh_seqno = seqno; assert(kmsg->ikm_header.msgh_size <= rcv_size); } else { mr = ipc_mqueue_receive(mqueue, option & MACH_RCV_TIMEOUT, MACH_MSG_SIZE_MAX, time_out, FALSE, mach_msg_receive_continue, &kmsg, &seqno); /* mqueue is unlocked */ ipc_object_release(object); if (mr != MACH_MSG_SUCCESS) return mr; kmsg->ikm_header.msgh_seqno = seqno; if (kmsg->ikm_header.msgh_size > rcv_size) { ipc_kmsg_copyout_dest(kmsg, space); (void) ipc_kmsg_put(msg, kmsg, sizeof *msg); return MACH_RCV_TOO_LARGE; } } if (option & MACH_RCV_NOTIFY) { if (notify == MACH_PORT_NULL) mr = MACH_RCV_INVALID_NOTIFY; else mr = ipc_kmsg_copyout(kmsg, space, map, notify); } else mr = ipc_kmsg_copyout(kmsg, space, map, MACH_PORT_NULL); if (mr != MACH_MSG_SUCCESS) { if ((mr &~ MACH_MSG_MASK) == MACH_RCV_BODY_ERROR) { (void) ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); } else { ipc_kmsg_copyout_dest(kmsg, space); (void) ipc_kmsg_put(msg, kmsg, sizeof *msg); } return mr; } return ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); } /* * Routine: mach_msg_receive_continue * Purpose: * Continue after blocking for a message. * Conditions: * Nothing locked. We are running on a new kernel stack, * with the receive state saved in the thread. From here * control goes back to user space. */ void mach_msg_receive_continue(void) { ipc_thread_t self = current_thread(); ipc_space_t space = current_space(); vm_map_t map = current_map(); mach_msg_header_t *msg = self->ith_msg; mach_msg_option_t option = self->ith_option; mach_msg_size_t rcv_size = self->ith_rcv_size; mach_msg_timeout_t time_out = self->ith_timeout; mach_port_t notify = self->ith_notify; ipc_object_t object = self->ith_object; ipc_mqueue_t mqueue = self->ith_mqueue; ipc_kmsg_t kmsg; mach_port_seqno_t seqno; mach_msg_return_t mr; if (option & MACH_RCV_LARGE) { mr = ipc_mqueue_receive(mqueue, option & MACH_RCV_TIMEOUT, rcv_size, time_out, TRUE, mach_msg_receive_continue, &kmsg, &seqno); /* mqueue is unlocked */ ipc_object_release(object); if (mr != MACH_MSG_SUCCESS) { if (mr == MACH_RCV_TOO_LARGE) { mach_msg_size_t real_size = (mach_msg_size_t) (vm_offset_t) kmsg; assert(real_size > rcv_size); (void) copyout(&real_size, &msg->msgh_size, sizeof(mach_msg_size_t)); } thread_syscall_return(mr); /*NOTREACHED*/ } kmsg->ikm_header.msgh_seqno = seqno; assert(kmsg->ikm_header.msgh_size <= rcv_size); } else { mr = ipc_mqueue_receive(mqueue, option & MACH_RCV_TIMEOUT, MACH_MSG_SIZE_MAX, time_out, TRUE, mach_msg_receive_continue, &kmsg, &seqno); /* mqueue is unlocked */ ipc_object_release(object); if (mr != MACH_MSG_SUCCESS) { thread_syscall_return(mr); /*NOTREACHED*/ } kmsg->ikm_header.msgh_seqno = seqno; if (kmsg->ikm_header.msgh_size > rcv_size) { ipc_kmsg_copyout_dest(kmsg, space); (void) ipc_kmsg_put(msg, kmsg, sizeof *msg); thread_syscall_return(MACH_RCV_TOO_LARGE); /*NOTREACHED*/ } } if (option & MACH_RCV_NOTIFY) { if (notify == MACH_PORT_NULL) mr = MACH_RCV_INVALID_NOTIFY; else mr = ipc_kmsg_copyout(kmsg, space, map, notify); } else mr = ipc_kmsg_copyout(kmsg, space, map, MACH_PORT_NULL); if (mr != MACH_MSG_SUCCESS) { if ((mr &~ MACH_MSG_MASK) == MACH_RCV_BODY_ERROR) { (void) ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); } else { ipc_kmsg_copyout_dest(kmsg, space); (void) ipc_kmsg_put(msg, kmsg, sizeof *msg); } thread_syscall_return(mr); /*NOTREACHED*/ } mr = ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); thread_syscall_return(mr); /*NOTREACHED*/ } /* * Routine: mach_msg_trap [mach trap] * Purpose: * Possibly send a message; possibly receive a message. * Conditions: * Nothing locked. * Returns: * All of mach_msg_send and mach_msg_receive error codes. */ mach_msg_return_t mach_msg_trap( mach_msg_header_t *msg, mach_msg_option_t option, mach_msg_size_t send_size, mach_msg_size_t rcv_size, mach_port_t rcv_name, mach_msg_timeout_t time_out, mach_port_t notify) { mach_msg_return_t mr; /* first check for common cases */ if (option == (MACH_SEND_MSG|MACH_RCV_MSG)) { ipc_thread_t self = current_thread(); ipc_space_t space = self->task->itk_space; ipc_kmsg_t kmsg; ipc_port_t dest_port; ipc_object_t rcv_object; ipc_mqueue_t rcv_mqueue; mach_msg_size_t reply_size; /* * This case is divided into ten sections, each * with a label. There are five optimized * sections and six unoptimized sections, which * do the same thing but handle all possible * cases and are slower. * * The five sections for an RPC are * 1) Get request message into a buffer. * (fast_get or slow_get) * 2) Copyin request message and rcv_name. * (fast_copyin or slow_copyin) * 3) Enqueue request and dequeue reply. * (fast_send_receive or * slow_send and slow_receive) * 4) Copyout reply message. * (fast_copyout or slow_copyout) * 5) Put reply message to user's buffer. * (fast_put or slow_put) * * Keep the locking hierarchy firmly in mind. * (First spaces, then ports, then port sets, * then message queues.) Only a non-blocking * attempt can be made to acquire locks out of * order, or acquire two locks on the same level. * Acquiring two locks on the same level will * fail if the objects are really the same, * unless simple locking is disabled. This is OK, * because then the extra unlock does nothing. * * There are two major reasons these RPCs can't use * ipc_thread_switch, and use slow_send/slow_receive: * 1) Kernel RPCs. * 2) Servers fall behind clients, so * client doesn't find a blocked server thread and * server finds waiting messages and can't block. */ /* fast_get: */ /* * optimized ipc_kmsg_get * * No locks, references, or messages held. * We must clear ikm_cache before copyinmsg. */ if ((send_size > IKM_SAVED_MSG_SIZE) || (send_size < sizeof(mach_msg_header_t)) || (send_size & 3) || ((kmsg = ikm_cache()) == IKM_NULL)) goto slow_get; ikm_cache() = IKM_NULL; ikm_check_initialized(kmsg, IKM_SAVED_KMSG_SIZE); if (copyinmsg(msg, &kmsg->ikm_header, send_size)) { ikm_free(kmsg); goto slow_get; } kmsg->ikm_header.msgh_size = send_size; fast_copyin: /* * optimized ipc_kmsg_copyin/ipc_mqueue_copyin * * We have the request message data in kmsg. * Must still do copyin, send, receive, etc. * * If the message isn't simple, we can't combine * ipc_kmsg_copyin_header and ipc_mqueue_copyin, * because copyin of the message body might * affect rcv_name. */ switch (kmsg->ikm_header.msgh_bits) { case MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, MACH_MSG_TYPE_MAKE_SEND_ONCE): { ipc_port_t reply_port; { mach_port_t reply_name = kmsg->ikm_header.msgh_local_port; if (reply_name != rcv_name) goto slow_copyin; is_read_lock(space); assert(space->is_active); ipc_entry_t entry; entry = ipc_entry_lookup (space, reply_name); if (entry == IE_NULL) goto abort_request_copyin; reply_port = (ipc_port_t) entry->ie_object; assert(reply_port != IP_NULL); } { mach_port_t dest_name = kmsg->ikm_header.msgh_remote_port; ipc_entry_t entry; ipc_entry_bits_t bits; entry = ipc_entry_lookup (space, dest_name); if (entry == IE_NULL) goto abort_request_copyin; bits = entry->ie_bits; /* check type bits */ if (IE_BITS_TYPE (bits) != MACH_PORT_TYPE_SEND) goto abort_request_copyin; assert(IE_BITS_UREFS(bits) > 0); dest_port = (ipc_port_t) entry->ie_object; assert(dest_port != IP_NULL); } /* * To do an atomic copyin, need simultaneous * locks on both ports and the space. If * dest_port == reply_port, and simple locking is * enabled, then we will abort. Otherwise it's * OK to unlock twice. */ ip_lock(dest_port); if (!ip_active(dest_port) || !ip_lock_try(reply_port)) { ip_unlock(dest_port); goto abort_request_copyin; } is_read_unlock(space); assert(dest_port->ip_srights > 0); dest_port->ip_srights++; ip_reference(dest_port); assert(ip_active(reply_port)); assert(reply_port->ip_receiver_name == kmsg->ikm_header.msgh_local_port); assert(reply_port->ip_receiver == space); reply_port->ip_sorights++; ip_reference(reply_port); kmsg->ikm_header.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND, MACH_MSG_TYPE_PORT_SEND_ONCE); kmsg->ikm_header.msgh_remote_port = (mach_port_t) dest_port; kmsg->ikm_header.msgh_local_port = (mach_port_t) reply_port; /* make sure we can queue to the destination */ if (dest_port->ip_receiver == ipc_space_kernel) { /* * The kernel server has a reference to * the reply port, which it hands back * to us in the reply message. We do * not need to keep another reference to * it. */ ip_unlock(reply_port); assert(ip_active(dest_port)); ip_unlock(dest_port); goto kernel_send; } if (dest_port->ip_msgcount >= dest_port->ip_qlimit) goto abort_request_send_receive; /* optimized ipc_mqueue_copyin */ if (reply_port->ip_pset != IPS_NULL) goto abort_request_send_receive; rcv_object = (ipc_object_t) reply_port; io_reference(rcv_object); rcv_mqueue = &reply_port->ip_messages; imq_lock(rcv_mqueue); io_unlock(rcv_object); goto fast_send_receive; abort_request_copyin: is_read_unlock(space); goto slow_copyin; abort_request_send_receive: ip_unlock(dest_port); ip_unlock(reply_port); goto slow_send; } case MACH_MSGH_BITS(MACH_MSG_TYPE_MOVE_SEND_ONCE, 0): { /* sending a reply message */ { mach_port_t reply_name = kmsg->ikm_header.msgh_local_port; if (reply_name != MACH_PORT_NULL) goto slow_copyin; } is_write_lock(space); assert(space->is_active); { ipc_entry_t entry; mach_port_t dest_name = kmsg->ikm_header.msgh_remote_port; entry = ipc_entry_lookup (space, dest_name); if (entry == IE_NULL) goto abort_reply_dest_copyin; /* check type bits */ if (IE_BITS_TYPE (entry->ie_bits) != MACH_PORT_TYPE_SEND_ONCE) goto abort_reply_dest_copyin; /* optimized ipc_right_copyin */ assert(IE_BITS_TYPE(entry->ie_bits) == MACH_PORT_TYPE_SEND_ONCE); assert(IE_BITS_UREFS(entry->ie_bits) == 1); assert((entry->ie_bits & IE_BITS_MAREQUEST) == 0); if (entry->ie_request != 0) goto abort_reply_dest_copyin; dest_port = (ipc_port_t) entry->ie_object; assert(dest_port != IP_NULL); ip_lock(dest_port); if (!ip_active(dest_port)) { ip_unlock(dest_port); goto abort_reply_dest_copyin; } assert(dest_port->ip_sorights > 0); entry->ie_object = IO_NULL; ipc_entry_dealloc (space, dest_name, entry); } kmsg->ikm_header.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND_ONCE, 0); kmsg->ikm_header.msgh_remote_port = (mach_port_t) dest_port; /* make sure we can queue to the destination */ assert(dest_port->ip_receiver != ipc_space_kernel); /* optimized ipc_mqueue_copyin */ { ipc_entry_t entry; ipc_entry_bits_t bits; entry = ipc_entry_lookup (space, rcv_name); if (entry == IE_NULL) goto abort_reply_rcv_copyin; bits = entry->ie_bits; /* check type bits; looking for receive or set */ if (bits & MACH_PORT_TYPE_PORT_SET) { ipc_pset_t rcv_pset; rcv_pset = (ipc_pset_t) entry->ie_object; assert(rcv_pset != IPS_NULL); ips_lock(rcv_pset); assert(ips_active(rcv_pset)); rcv_object = (ipc_object_t) rcv_pset; rcv_mqueue = &rcv_pset->ips_messages; } else if (bits & MACH_PORT_TYPE_RECEIVE) { ipc_port_t rcv_port; rcv_port = (ipc_port_t) entry->ie_object; assert(rcv_port != IP_NULL); if (!ip_lock_try(rcv_port)) goto abort_reply_rcv_copyin; assert(ip_active(rcv_port)); if (rcv_port->ip_pset != IPS_NULL) { ip_unlock(rcv_port); goto abort_reply_rcv_copyin; } rcv_object = (ipc_object_t) rcv_port; rcv_mqueue = &rcv_port->ip_messages; } else goto abort_reply_rcv_copyin; } is_write_unlock(space); io_reference(rcv_object); imq_lock(rcv_mqueue); io_unlock(rcv_object); goto fast_send_receive; abort_reply_dest_copyin: is_write_unlock(space); goto slow_copyin; abort_reply_rcv_copyin: ip_unlock(dest_port); is_write_unlock(space); goto slow_send; } default: goto slow_copyin; } /*NOTREACHED*/ fast_send_receive: /* * optimized ipc_mqueue_send/ipc_mqueue_receive * * Finished get/copyin of kmsg and copyin of rcv_name. * space is unlocked, dest_port is locked, * we can queue kmsg to dest_port, * rcv_mqueue is locked, rcv_object holds a ref, * if rcv_object is a port it isn't in a port set * * Note that if simple locking is turned off, * then we could have dest_mqueue == rcv_mqueue * and not abort when we try to lock dest_mqueue. */ assert(ip_active(dest_port)); assert(dest_port->ip_receiver != ipc_space_kernel); assert((dest_port->ip_msgcount < dest_port->ip_qlimit) || (MACH_MSGH_BITS_REMOTE(kmsg->ikm_header.msgh_bits) == MACH_MSG_TYPE_PORT_SEND_ONCE)); assert((kmsg->ikm_header.msgh_bits & MACH_MSGH_BITS_CIRCULAR) == 0); { ipc_mqueue_t dest_mqueue; ipc_thread_t receiver; { 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)) { abort_send_receive: ip_unlock(dest_port); imq_unlock(rcv_mqueue); ipc_object_release(rcv_object); goto slow_send; } receiver = ipc_thread_queue_first(&dest_mqueue->imq_threads); if ((receiver == ITH_NULL) || (ipc_kmsg_queue_first(&rcv_mqueue->imq_messages) != IKM_NULL)) { imq_unlock(dest_mqueue); goto abort_send_receive; } /* * There is a receiver thread waiting, and * there is no reply message for us to pick up. * We have hope of hand-off, so save state. */ self->ith_msg = msg; self->ith_rcv_size = rcv_size; self->ith_object = rcv_object; self->ith_mqueue = rcv_mqueue; if ((receiver->swap_func == (void (*)()) mach_msg_continue) && thread_handoff(self, mach_msg_continue, receiver)) { assert(current_thread() == receiver); /* * We can use the optimized receive code, * because the receiver is using no options. */ } else if ((receiver->swap_func == (void (*)()) exception_raise_continue) && thread_handoff(self, mach_msg_continue, receiver)) { counter(c_mach_msg_trap_block_exc++); assert(current_thread() == receiver); /* * We are a reply message coming back through * the optimized exception-handling path. * Finish with rcv_mqueue and dest_mqueue, * and then jump to exception code with * dest_port still locked. We don't bother * with a sequence number in this case. */ ipc_thread_enqueue_macro( &rcv_mqueue->imq_threads, self); self->ith_state = MACH_RCV_IN_PROGRESS; self->ith_msize = MACH_MSG_SIZE_MAX; imq_unlock(rcv_mqueue); ipc_thread_rmqueue_first_macro( &dest_mqueue->imq_threads, receiver); imq_unlock(dest_mqueue); exception_raise_continue_fast(dest_port, kmsg); /*NOTREACHED*/ return MACH_MSG_SUCCESS; } else if ((send_size <= receiver->ith_msize) && thread_handoff(self, mach_msg_continue, receiver)) { assert(current_thread() == receiver); if ((receiver->swap_func == (void (*)()) mach_msg_receive_continue) && ((receiver->ith_option & MACH_RCV_NOTIFY) == 0)) { /* * We can still use the optimized code. */ } else { counter(c_mach_msg_trap_block_slow++); /* * We are running as the receiver, * but we can't use the optimized code. * Finish send/receive processing. */ dest_port->ip_msgcount++; ip_unlock(dest_port); ipc_thread_enqueue_macro( &rcv_mqueue->imq_threads, self); self->ith_state = MACH_RCV_IN_PROGRESS; self->ith_msize = MACH_MSG_SIZE_MAX; imq_unlock(rcv_mqueue); ipc_thread_rmqueue_first_macro( &dest_mqueue->imq_threads, receiver); receiver->ith_state = MACH_MSG_SUCCESS; receiver->ith_kmsg = kmsg; receiver->ith_seqno = dest_port->ip_seqno++; imq_unlock(dest_mqueue); /* * Call the receiver's continuation. */ receiver->wait_result = THREAD_AWAKENED; (*receiver->swap_func)(); /*NOTREACHED*/ return MACH_MSG_SUCCESS; } } else { /* * The receiver can't accept the message, * or we can't switch to the receiver. */ imq_unlock(dest_mqueue); goto abort_send_receive; } counter(c_mach_msg_trap_block_fast++); /* * Safe to unlock dest_port now that we are * committed to this path, because we hold * dest_mqueue locked. We never bother changing * dest_port->ip_msgcount. */ ip_unlock(dest_port); /* * We need to finish preparing self for its * time asleep in rcv_mqueue. */ ipc_thread_enqueue_macro(&rcv_mqueue->imq_threads, self); self->ith_state = MACH_RCV_IN_PROGRESS; self->ith_msize = MACH_MSG_SIZE_MAX; imq_unlock(rcv_mqueue); /* * Finish extracting receiver from dest_mqueue. */ ipc_thread_rmqueue_first_macro( &dest_mqueue->imq_threads, receiver); kmsg->ikm_header.msgh_seqno = dest_port->ip_seqno++; imq_unlock(dest_mqueue); /* * We don't have to do any post-dequeue processing of * the message. We never incremented ip_msgcount, we * know it has no msg-accepted request, and blocked * senders aren't a worry because we found the port * with a receiver waiting. */ self = receiver; space = self->task->itk_space; msg = self->ith_msg; rcv_size = self->ith_rcv_size; rcv_object = self->ith_object; /* inline ipc_object_release */ io_lock(rcv_object); io_release(rcv_object); io_check_unlock(rcv_object); } fast_copyout: /* * Nothing locked and no references held, except * we have kmsg with msgh_seqno filled in. Must * still check against rcv_size and do * ipc_kmsg_copyout/ipc_kmsg_put. */ assert((ipc_port_t) kmsg->ikm_header.msgh_remote_port == dest_port); reply_size = kmsg->ikm_header.msgh_size; if (rcv_size < reply_size) goto slow_copyout; /* optimized ipc_kmsg_copyout/ipc_kmsg_copyout_header */ switch (kmsg->ikm_header.msgh_bits) { case MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND, MACH_MSG_TYPE_PORT_SEND_ONCE): { ipc_port_t reply_port = (ipc_port_t) kmsg->ikm_header.msgh_local_port; mach_port_t dest_name, reply_name; unsigned long payload; /* receiving a request message */ if (!IP_VALID(reply_port)) goto slow_copyout; is_write_lock(space); assert(space->is_active); /* * To do an atomic copyout, need simultaneous * locks on both ports and the space. If * dest_port == reply_port, and simple locking is * enabled, then we will abort. Otherwise it's * OK to unlock twice. */ ip_lock(dest_port); if (!ip_active(dest_port) || !ip_lock_try(reply_port)) goto abort_request_copyout; if (!ip_active(reply_port)) { ip_unlock(reply_port); goto abort_request_copyout; } assert(reply_port->ip_sorights > 0); ip_unlock(reply_port); { ipc_entry_t entry; kern_return_t kr; kr = ipc_entry_get (space, &reply_name, &entry); if (kr) goto abort_request_copyout; assert (entry != NULL); { 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); } assert(MACH_PORT_VALID(reply_name)); 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); if (dest_port->ip_receiver == space) dest_name = dest_port->ip_receiver_name; else dest_name = MACH_PORT_NULL; payload = dest_port->ip_protected_payload; 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); if (! ipc_port_flag_protected_payload(dest_port)) { kmsg->ikm_header.msgh_bits = MACH_MSGH_BITS( MACH_MSG_TYPE_PORT_SEND_ONCE, MACH_MSG_TYPE_PORT_SEND); kmsg->ikm_header.msgh_local_port = dest_name; } else { kmsg->ikm_header.msgh_bits = MACH_MSGH_BITS( MACH_MSG_TYPE_PORT_SEND_ONCE, MACH_MSG_TYPE_PROTECTED_PAYLOAD); kmsg->ikm_header.msgh_protected_payload = payload; } kmsg->ikm_header.msgh_remote_port = reply_name; goto fast_put; abort_request_copyout: ip_unlock(dest_port); is_write_unlock(space); goto slow_copyout; } case MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND_ONCE, 0): { mach_port_t dest_name; unsigned long payload; /* receiving a reply message */ ip_lock(dest_port); if (!ip_active(dest_port)) goto slow_copyout; /* optimized ipc_object_copyout_dest */ assert(dest_port->ip_sorights > 0); payload = dest_port->ip_protected_payload; if (dest_port->ip_receiver == space) { ip_release(dest_port); dest_port->ip_sorights--; dest_name = dest_port->ip_receiver_name; ip_unlock(dest_port); } else { ip_unlock(dest_port); ipc_notify_send_once(dest_port); dest_name = MACH_PORT_NULL; } if (! ipc_port_flag_protected_payload(dest_port)) { kmsg->ikm_header.msgh_bits = MACH_MSGH_BITS( 0, MACH_MSG_TYPE_PORT_SEND_ONCE); kmsg->ikm_header.msgh_local_port = dest_name; } else { kmsg->ikm_header.msgh_bits = MACH_MSGH_BITS( 0, MACH_MSG_TYPE_PROTECTED_PAYLOAD); kmsg->ikm_header.msgh_protected_payload = payload; } kmsg->ikm_header.msgh_remote_port = MACH_PORT_NULL; goto fast_put; } case MACH_MSGH_BITS_COMPLEX| MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND_ONCE, 0): { mach_port_t dest_name; unsigned long payload; /* receiving a complex reply message */ ip_lock(dest_port); if (!ip_active(dest_port)) goto slow_copyout; /* optimized ipc_object_copyout_dest */ assert(dest_port->ip_sorights > 0); payload = dest_port->ip_protected_payload; if (dest_port->ip_receiver == space) { ip_release(dest_port); dest_port->ip_sorights--; dest_name = dest_port->ip_receiver_name; ip_unlock(dest_port); } else { ip_unlock(dest_port); ipc_notify_send_once(dest_port); dest_name = MACH_PORT_NULL; } if (! ipc_port_flag_protected_payload(dest_port)) { kmsg->ikm_header.msgh_bits = MACH_MSGH_BITS_COMPLEX | MACH_MSGH_BITS( 0, MACH_MSG_TYPE_PORT_SEND_ONCE); kmsg->ikm_header.msgh_local_port = dest_name; } else { kmsg->ikm_header.msgh_bits = MACH_MSGH_BITS_COMPLEX | MACH_MSGH_BITS( 0, MACH_MSG_TYPE_PROTECTED_PAYLOAD); kmsg->ikm_header.msgh_protected_payload = payload; } kmsg->ikm_header.msgh_remote_port = MACH_PORT_NULL; mr = ipc_kmsg_copyout_body( (vm_offset_t) (&kmsg->ikm_header + 1), (vm_offset_t) &kmsg->ikm_header + kmsg->ikm_header.msgh_size, space, current_map()); if (mr != MACH_MSG_SUCCESS) { (void) ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); return mr | MACH_RCV_BODY_ERROR; } goto fast_put; } default: goto slow_copyout; } /*NOTREACHED*/ fast_put: /* * We have the reply message data in kmsg, * and the reply message size in reply_size. * Just need to copy it out to the user and free kmsg. * We must check ikm_cache after copyoutmsg. */ ikm_check_initialized(kmsg, kmsg->ikm_size); if ((kmsg->ikm_size != IKM_SAVED_KMSG_SIZE) || copyoutmsg(&kmsg->ikm_header, msg, reply_size) || (ikm_cache() != IKM_NULL)) goto slow_put; ikm_cache() = kmsg; thread_syscall_return(MACH_MSG_SUCCESS); /*NOTREACHED*/ return MACH_MSG_SUCCESS; /* help for the compiler */ /* * The slow path has a few non-register temporary * variables used only for call-by-reference. */ { ipc_kmsg_t temp_kmsg; mach_port_seqno_t temp_seqno; ipc_object_t temp_rcv_object; ipc_mqueue_t temp_rcv_mqueue; slow_get: /* * No locks, references, or messages held. * Still have to get the request, send it, * receive reply, etc. */ mr = ipc_kmsg_get(msg, send_size, &temp_kmsg); if (mr != MACH_MSG_SUCCESS) { thread_syscall_return(mr); /*NOTREACHED*/ } kmsg = temp_kmsg; /* try to get back on optimized path */ goto fast_copyin; slow_copyin: /* * We have the message data in kmsg, but * we still need to copyin, send it, * receive a reply, and do copyout. */ mr = ipc_kmsg_copyin(kmsg, space, current_map(), MACH_PORT_NULL); if (mr != MACH_MSG_SUCCESS) { ikm_free(kmsg); thread_syscall_return(mr); /*NOTREACHED*/ } /* try to get back on optimized path */ if (kmsg->ikm_header.msgh_bits & MACH_MSGH_BITS_CIRCULAR) goto slow_send; dest_port = (ipc_port_t) kmsg->ikm_header.msgh_remote_port; assert(IP_VALID(dest_port)); ip_lock(dest_port); if (dest_port->ip_receiver == ipc_space_kernel) { assert(ip_active(dest_port)); ip_unlock(dest_port); goto kernel_send; } if (ip_active(dest_port) && ((dest_port->ip_msgcount < dest_port->ip_qlimit) || (MACH_MSGH_BITS_REMOTE(kmsg->ikm_header.msgh_bits) == MACH_MSG_TYPE_PORT_SEND_ONCE))) { /* * Try an optimized ipc_mqueue_copyin. * It will work if this is a request message. */ ipc_port_t reply_port; reply_port = (ipc_port_t) kmsg->ikm_header.msgh_local_port; if (IP_VALID(reply_port)) { if (ip_lock_try(reply_port)) { if (ip_active(reply_port) && reply_port->ip_receiver == space && reply_port->ip_receiver_name == rcv_name && reply_port->ip_pset == IPS_NULL) { /* Grab a reference to the reply port. */ rcv_object = (ipc_object_t) reply_port; io_reference(rcv_object); rcv_mqueue = &reply_port->ip_messages; imq_lock(rcv_mqueue); io_unlock(rcv_object); goto fast_send_receive; } ip_unlock(reply_port); } } } ip_unlock(dest_port); goto slow_send; kernel_send: /* * Special case: send message to kernel services. * The request message has been copied into the * kmsg. Nothing is locked. */ { ipc_port_t reply_port; /* * Perform the kernel function. */ kmsg = ipc_kobject_server(kmsg); if (kmsg == IKM_NULL) { /* * No reply. Take the * slow receive path. */ goto slow_get_rcv_port; } /* * Check that: * the reply port is alive * we hold the receive right * the name has not changed. * the port is not in a set * If any of these are not true, * we cannot directly receive the reply * message. */ reply_port = (ipc_port_t) kmsg->ikm_header.msgh_remote_port; ip_lock(reply_port); if ((!ip_active(reply_port)) || (reply_port->ip_receiver != space) || (reply_port->ip_receiver_name != rcv_name) || (reply_port->ip_pset != IPS_NULL)) { ip_unlock(reply_port); ipc_mqueue_send_always(kmsg); goto slow_get_rcv_port; } rcv_mqueue = &reply_port->ip_messages; imq_lock(rcv_mqueue); /* keep port locked, and don`t change ref count yet */ /* * If there are messages on the port * or other threads waiting for a message, * we cannot directly receive the reply. */ if ((ipc_thread_queue_first(&rcv_mqueue->imq_threads) != ITH_NULL) || (ipc_kmsg_queue_first(&rcv_mqueue->imq_messages) != IKM_NULL)) { imq_unlock(rcv_mqueue); ip_unlock(reply_port); ipc_mqueue_send_always(kmsg); goto slow_get_rcv_port; } /* * We can directly receive this reply. * Since the kernel reply never blocks, * it holds no message_accepted request. * Since there were no messages queued * on the reply port, there should be * no threads blocked waiting to send. */ assert(kmsg->ikm_marequest == IMAR_NULL); assert(ipc_thread_queue_first(&reply_port->ip_blocked) == ITH_NULL); dest_port = reply_port; kmsg->ikm_header.msgh_seqno = dest_port->ip_seqno++; imq_unlock(rcv_mqueue); /* * inline ipc_object_release. * Port is still locked. * Reference count was not incremented. */ ip_check_unlock(reply_port); /* copy out the kernel reply */ goto fast_copyout; } slow_send: /* * Nothing is locked. We have acquired kmsg, but * we still need to send it and receive a reply. */ mr = ipc_mqueue_send(kmsg, MACH_MSG_OPTION_NONE, MACH_MSG_TIMEOUT_NONE); if (mr != MACH_MSG_SUCCESS) { mr |= ipc_kmsg_copyout_pseudo(kmsg, space, current_map()); assert(kmsg->ikm_marequest == IMAR_NULL); (void) ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); thread_syscall_return(mr); /*NOTREACHED*/ } slow_get_rcv_port: /* * We have sent the message. Copy in the receive port. */ mr = ipc_mqueue_copyin(space, rcv_name, &temp_rcv_mqueue, &temp_rcv_object); if (mr != MACH_MSG_SUCCESS) { thread_syscall_return(mr); /*NOTREACHED*/ } rcv_mqueue = temp_rcv_mqueue; rcv_object = temp_rcv_object; /* hold ref for rcv_object; rcv_mqueue is locked */ /* slow_receive: */ /* * Now we have sent the request and copied in rcv_name, * so rcv_mqueue is locked and hold ref for rcv_object. * Just receive a reply and try to get back to fast path. * * ipc_mqueue_receive may not return, because if we block * then our kernel stack may be discarded. So we save * state here for mach_msg_continue to pick up. */ self->ith_msg = msg; self->ith_rcv_size = rcv_size; self->ith_object = rcv_object; self->ith_mqueue = rcv_mqueue; mr = ipc_mqueue_receive(rcv_mqueue, MACH_MSG_OPTION_NONE, MACH_MSG_SIZE_MAX, MACH_MSG_TIMEOUT_NONE, FALSE, mach_msg_continue, &temp_kmsg, &temp_seqno); /* rcv_mqueue is unlocked */ ipc_object_release(rcv_object); if (mr != MACH_MSG_SUCCESS) { thread_syscall_return(mr); /*NOTREACHED*/ } (kmsg = temp_kmsg)->ikm_header.msgh_seqno = temp_seqno; dest_port = (ipc_port_t) kmsg->ikm_header.msgh_remote_port; goto fast_copyout; slow_copyout: /* * Nothing locked and no references held, except * we have kmsg with msgh_seqno filled in. Must * still check against rcv_size and do * ipc_kmsg_copyout/ipc_kmsg_put. */ reply_size = kmsg->ikm_header.msgh_size; if (rcv_size < reply_size) { ipc_kmsg_copyout_dest(kmsg, space); (void) ipc_kmsg_put(msg, kmsg, sizeof *msg); thread_syscall_return(MACH_RCV_TOO_LARGE); /*NOTREACHED*/ } mr = ipc_kmsg_copyout(kmsg, space, current_map(), MACH_PORT_NULL); if (mr != MACH_MSG_SUCCESS) { if ((mr &~ MACH_MSG_MASK) == MACH_RCV_BODY_ERROR) { (void) ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); } else { ipc_kmsg_copyout_dest(kmsg, space); (void) ipc_kmsg_put(msg, kmsg, sizeof *msg); } thread_syscall_return(mr); /*NOTREACHED*/ } /* try to get back on optimized path */ goto fast_put; slow_put: mr = ipc_kmsg_put(msg, kmsg, reply_size); thread_syscall_return(mr); /*NOTREACHED*/ } } else if (option == MACH_SEND_MSG) { ipc_space_t space = current_space(); vm_map_t map = current_map(); ipc_kmsg_t kmsg; mr = ipc_kmsg_get(msg, send_size, &kmsg); if (mr != MACH_MSG_SUCCESS) return mr; mr = ipc_kmsg_copyin(kmsg, space, map, MACH_PORT_NULL); if (mr != MACH_MSG_SUCCESS) { ikm_free(kmsg); return mr; } mr = ipc_mqueue_send(kmsg, MACH_MSG_OPTION_NONE, MACH_MSG_TIMEOUT_NONE); if (mr != MACH_MSG_SUCCESS) { mr |= ipc_kmsg_copyout_pseudo(kmsg, space, map); assert(kmsg->ikm_marequest == IMAR_NULL); (void) ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); } return mr; } else if (option == MACH_RCV_MSG) { ipc_thread_t self = current_thread(); ipc_space_t space = current_space(); vm_map_t map = current_map(); ipc_object_t object; ipc_mqueue_t mqueue; ipc_kmsg_t kmsg; mach_port_seqno_t seqno; mr = ipc_mqueue_copyin(space, rcv_name, &mqueue, &object); if (mr != MACH_MSG_SUCCESS) return mr; /* hold ref for object; mqueue is locked */ /* * ipc_mqueue_receive may not return, because if we block * then our kernel stack may be discarded. So we save * state here for mach_msg_continue to pick up. */ self->ith_msg = msg; self->ith_rcv_size = rcv_size; self->ith_object = object; self->ith_mqueue = mqueue; mr = ipc_mqueue_receive(mqueue, MACH_MSG_OPTION_NONE, MACH_MSG_SIZE_MAX, MACH_MSG_TIMEOUT_NONE, FALSE, mach_msg_continue, &kmsg, &seqno); /* mqueue is unlocked */ ipc_object_release(object); if (mr != MACH_MSG_SUCCESS) return mr; kmsg->ikm_header.msgh_seqno = seqno; if (rcv_size < kmsg->ikm_header.msgh_size) { ipc_kmsg_copyout_dest(kmsg, space); (void) ipc_kmsg_put(msg, kmsg, sizeof *msg); return MACH_RCV_TOO_LARGE; } mr = ipc_kmsg_copyout(kmsg, space, map, MACH_PORT_NULL); if (mr != MACH_MSG_SUCCESS) { if ((mr &~ MACH_MSG_MASK) == MACH_RCV_BODY_ERROR) { (void) ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); } else { ipc_kmsg_copyout_dest(kmsg, space); (void) ipc_kmsg_put(msg, kmsg, sizeof *msg); } return mr; } return ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); } else if (option == MACH_MSG_OPTION_NONE) { /* * We can measure the "null mach_msg_trap" * (syscall entry and thread_syscall_return exit) * with this path. */ thread_syscall_return(MACH_MSG_SUCCESS); /*NOTREACHED*/ } if (option & MACH_SEND_MSG) { mr = mach_msg_send(msg, option, send_size, time_out, notify); if (mr != MACH_MSG_SUCCESS) return mr; } if (option & MACH_RCV_MSG) { mr = mach_msg_receive(msg, option, rcv_size, rcv_name, time_out, notify); if (mr != MACH_MSG_SUCCESS) return mr; } return MACH_MSG_SUCCESS; } /* * Routine: mach_msg_continue * Purpose: * Continue after blocking for a message. * Conditions: * Nothing locked. We are running on a new kernel stack, * with the receive state saved in the thread. From here * control goes back to user space. */ void mach_msg_continue(void) { ipc_thread_t thread = current_thread(); task_t task = thread->task; ipc_space_t space = task->itk_space; vm_map_t map = task->map; mach_msg_header_t *msg = thread->ith_msg; mach_msg_size_t rcv_size = thread->ith_rcv_size; ipc_object_t object = thread->ith_object; ipc_mqueue_t mqueue = thread->ith_mqueue; ipc_kmsg_t kmsg; mach_port_seqno_t seqno; mach_msg_return_t mr; mr = ipc_mqueue_receive(mqueue, MACH_MSG_OPTION_NONE, MACH_MSG_SIZE_MAX, MACH_MSG_TIMEOUT_NONE, TRUE, mach_msg_continue, &kmsg, &seqno); /* mqueue is unlocked */ ipc_object_release(object); if (mr != MACH_MSG_SUCCESS) { thread_syscall_return(mr); /*NOTREACHED*/ } kmsg->ikm_header.msgh_seqno = seqno; if (kmsg->ikm_header.msgh_size > rcv_size) { ipc_kmsg_copyout_dest(kmsg, space); (void) ipc_kmsg_put(msg, kmsg, sizeof *msg); thread_syscall_return(MACH_RCV_TOO_LARGE); /*NOTREACHED*/ } mr = ipc_kmsg_copyout(kmsg, space, map, MACH_PORT_NULL); if (mr != MACH_MSG_SUCCESS) { if ((mr &~ MACH_MSG_MASK) == MACH_RCV_BODY_ERROR) { (void) ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); } else { ipc_kmsg_copyout_dest(kmsg, space); (void) ipc_kmsg_put(msg, kmsg, sizeof *msg); } thread_syscall_return(mr); /*NOTREACHED*/ } mr = ipc_kmsg_put(msg, kmsg, kmsg->ikm_header.msgh_size); thread_syscall_return(mr); /*NOTREACHED*/ } /* * Routine: mach_msg_interrupt * Purpose: * Attempts to force a thread waiting at mach_msg_continue or * mach_msg_receive_continue into a clean point. Returns TRUE * if this was possible. * Conditions: * Nothing locked. The thread must NOT be runnable. */ boolean_t mach_msg_interrupt(thread_t thread) { ipc_mqueue_t mqueue; assert((thread->swap_func == (void (*)()) mach_msg_continue) || (thread->swap_func == (void (*)()) mach_msg_receive_continue)); mqueue = thread->ith_mqueue; imq_lock(mqueue); if (thread->ith_state != MACH_RCV_IN_PROGRESS) { /* * The thread is no longer waiting for a message. * It may have a message sitting in ith_kmsg. * We can't clean this up. */ imq_unlock(mqueue); return FALSE; } ipc_thread_rmqueue(&mqueue->imq_threads, thread); imq_unlock(mqueue); ipc_object_release(thread->ith_object); thread_set_syscall_return(thread, MACH_RCV_INTERRUPTED); thread->swap_func = thread_exception_return; return TRUE; }