xnu-4903.270.47.tar.gz

[apple/xnu.git] / osfmk / kern / ipc_tt.c

/*
 * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/*
 * Mach Operating System
 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
 * 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 ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS 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.
 */
/*
 * NOTICE: This file was modified by McAfee Research in 2004 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 */
/*
 */

/*
 * File:        ipc_tt.c
 * Purpose:
 *      Task and thread related IPC functions.
 */

#include <mach/mach_types.h>
#include <mach/boolean.h>
#include <mach/kern_return.h>
#include <mach/mach_param.h>
#include <mach/task_special_ports.h>
#include <mach/thread_special_ports.h>
#include <mach/thread_status.h>
#include <mach/exception_types.h>
#include <mach/memory_object_types.h>
#include <mach/mach_traps.h>
#include <mach/task_server.h>
#include <mach/thread_act_server.h>
#include <mach/mach_host_server.h>
#include <mach/host_priv_server.h>
#include <mach/vm_map_server.h>

#include <kern/kern_types.h>
#include <kern/host.h>
#include <kern/ipc_kobject.h>
#include <kern/ipc_tt.h>
#include <kern/kalloc.h>
#include <kern/thread.h>
#include <kern/misc_protos.h>

#include <vm/vm_map.h>
#include <vm/vm_pageout.h>
#include <vm/vm_protos.h>

#include <security/mac_mach_internal.h>

#if CONFIG_EMBEDDED && !SECURE_KERNEL
extern int cs_relax_platform_task_ports;
#endif

/* forward declarations */
task_t convert_port_to_locked_task(ipc_port_t port);
task_inspect_t convert_port_to_locked_task_inspect(ipc_port_t port);
static void ipc_port_bind_special_reply_port_locked(ipc_port_t port);
static kern_return_t ipc_port_unbind_special_reply_port(thread_t thread, boolean_t unbind_active_port);
kern_return_t task_conversion_eval(task_t caller, task_t victim);

/*
 *      Routine:        ipc_task_init
 *      Purpose:
 *              Initialize a task's IPC state.
 *
 *              If non-null, some state will be inherited from the parent.
 *              The parent must be appropriately initialized.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_task_init(
        task_t          task,
        task_t          parent)
{
        ipc_space_t space;
        ipc_port_t kport;
        ipc_port_t nport;
        kern_return_t kr;
        int i;


        kr = ipc_space_create(&ipc_table_entries[0], &space);
        if (kr != KERN_SUCCESS) {
                panic("ipc_task_init");
        }

        space->is_task = task;

        kport = ipc_port_alloc_kernel();
        if (kport == IP_NULL) {
                panic("ipc_task_init");
        }

        nport = ipc_port_alloc_kernel();
        if (nport == IP_NULL) {
                panic("ipc_task_init");
        }

        itk_lock_init(task);
        task->itk_self = kport;
        task->itk_nself = nport;
        task->itk_resume = IP_NULL; /* Lazily allocated on-demand */
        if (task_is_a_corpse_fork(task)) {
                /*
                 * No sender's notification for corpse would not
                 * work with a naked send right in kernel.
                 */
                task->itk_sself = IP_NULL;
        } else {
                task->itk_sself = ipc_port_make_send(kport);
        }
        task->itk_debug_control = IP_NULL;
        task->itk_space = space;

#if CONFIG_MACF
        task->exc_actions[0].label = NULL;
        for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; i++) {
                mac_exc_associate_action_label(&task->exc_actions[i], mac_exc_create_label());
        }
#endif

        /* always zero-out the first (unused) array element */
        bzero(&task->exc_actions[0], sizeof(task->exc_actions[0]));

        if (parent == TASK_NULL) {
                ipc_port_t port;
                for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; i++) {
                        task->exc_actions[i].port = IP_NULL;
                        task->exc_actions[i].flavor = 0;
                        task->exc_actions[i].behavior = 0;
                        task->exc_actions[i].privileged = FALSE;
                }/* for */

                kr = host_get_host_port(host_priv_self(), &port);
                assert(kr == KERN_SUCCESS);
                task->itk_host = port;

                task->itk_bootstrap = IP_NULL;
                task->itk_seatbelt = IP_NULL;
                task->itk_gssd = IP_NULL;
                task->itk_task_access = IP_NULL;

                for (i = 0; i < TASK_PORT_REGISTER_MAX; i++) {
                        task->itk_registered[i] = IP_NULL;
                }
        } else {
                itk_lock(parent);
                assert(parent->itk_self != IP_NULL);

                /* inherit registered ports */

                for (i = 0; i < TASK_PORT_REGISTER_MAX; i++) {
                        task->itk_registered[i] =
                            ipc_port_copy_send(parent->itk_registered[i]);
                }

                /* inherit exception and bootstrap ports */

                for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; i++) {
                        task->exc_actions[i].port =
                            ipc_port_copy_send(parent->exc_actions[i].port);
                        task->exc_actions[i].flavor =
                            parent->exc_actions[i].flavor;
                        task->exc_actions[i].behavior =
                            parent->exc_actions[i].behavior;
                        task->exc_actions[i].privileged =
                            parent->exc_actions[i].privileged;
#if CONFIG_MACF
                        mac_exc_inherit_action_label(parent->exc_actions + i, task->exc_actions + i);
#endif
                }/* for */
                task->itk_host =
                    ipc_port_copy_send(parent->itk_host);

                task->itk_bootstrap =
                    ipc_port_copy_send(parent->itk_bootstrap);

                task->itk_seatbelt =
                    ipc_port_copy_send(parent->itk_seatbelt);

                task->itk_gssd =
                    ipc_port_copy_send(parent->itk_gssd);

                task->itk_task_access =
                    ipc_port_copy_send(parent->itk_task_access);

                itk_unlock(parent);
        }
}

/*
 *      Routine:        ipc_task_enable
 *      Purpose:
 *              Enable a task for IPC access.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_task_enable(
        task_t          task)
{
        ipc_port_t kport;
        ipc_port_t nport;

        itk_lock(task);
        kport = task->itk_self;
        if (kport != IP_NULL) {
                ipc_kobject_set(kport, (ipc_kobject_t) task, IKOT_TASK);
        }
        nport = task->itk_nself;
        if (nport != IP_NULL) {
                ipc_kobject_set(nport, (ipc_kobject_t) task, IKOT_TASK_NAME);
        }
        itk_unlock(task);
}

/*
 *      Routine:        ipc_task_disable
 *      Purpose:
 *              Disable IPC access to a task.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_task_disable(
        task_t          task)
{
        ipc_port_t kport;
        ipc_port_t nport;
        ipc_port_t rport;

        itk_lock(task);
        kport = task->itk_self;
        if (kport != IP_NULL) {
                ipc_kobject_set(kport, IKO_NULL, IKOT_NONE);
        }
        nport = task->itk_nself;
        if (nport != IP_NULL) {
                ipc_kobject_set(nport, IKO_NULL, IKOT_NONE);
        }

        rport = task->itk_resume;
        if (rport != IP_NULL) {
                /*
                 * From this point onwards this task is no longer accepting
                 * resumptions.
                 *
                 * There are still outstanding suspensions on this task,
                 * even as it is being torn down. Disconnect the task
                 * from the rport, thereby "orphaning" the rport. The rport
                 * itself will go away only when the last suspension holder
                 * destroys his SO right to it -- when he either
                 * exits, or tries to actually use that last SO right to
                 * resume this (now non-existent) task.
                 */
                ipc_kobject_set(rport, IKO_NULL, IKOT_NONE);
        }
        itk_unlock(task);
}

/*
 *      Routine:        ipc_task_terminate
 *      Purpose:
 *              Clean up and destroy a task's IPC state.
 *      Conditions:
 *              Nothing locked.  The task must be suspended.
 *              (Or the current thread must be in the task.)
 */

void
ipc_task_terminate(
        task_t          task)
{
        ipc_port_t kport;
        ipc_port_t nport;
        ipc_port_t rport;
        int i;

        itk_lock(task);
        kport = task->itk_self;

        if (kport == IP_NULL) {
                /* the task is already terminated (can this happen?) */
                itk_unlock(task);
                return;
        }
        task->itk_self = IP_NULL;

        nport = task->itk_nself;
        assert(nport != IP_NULL);
        task->itk_nself = IP_NULL;

        rport = task->itk_resume;
        task->itk_resume = IP_NULL;

        itk_unlock(task);

        /* release the naked send rights */

        if (IP_VALID(task->itk_sself)) {
                ipc_port_release_send(task->itk_sself);
        }

        for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; i++) {
                if (IP_VALID(task->exc_actions[i].port)) {
                        ipc_port_release_send(task->exc_actions[i].port);
                }
#if CONFIG_MACF
                mac_exc_free_action_label(task->exc_actions + i);
#endif
        }

        if (IP_VALID(task->itk_host)) {
                ipc_port_release_send(task->itk_host);
        }

        if (IP_VALID(task->itk_bootstrap)) {
                ipc_port_release_send(task->itk_bootstrap);
        }

        if (IP_VALID(task->itk_seatbelt)) {
                ipc_port_release_send(task->itk_seatbelt);
        }

        if (IP_VALID(task->itk_gssd)) {
                ipc_port_release_send(task->itk_gssd);
        }

        if (IP_VALID(task->itk_task_access)) {
                ipc_port_release_send(task->itk_task_access);
        }

        if (IP_VALID(task->itk_debug_control)) {
                ipc_port_release_send(task->itk_debug_control);
        }

        for (i = 0; i < TASK_PORT_REGISTER_MAX; i++) {
                if (IP_VALID(task->itk_registered[i])) {
                        ipc_port_release_send(task->itk_registered[i]);
                }
        }

        /* destroy the kernel ports */
        ipc_port_dealloc_kernel(kport);
        ipc_port_dealloc_kernel(nport);
        if (rport != IP_NULL) {
                ipc_port_dealloc_kernel(rport);
        }

        itk_lock_destroy(task);
}

/*
 *      Routine:        ipc_task_reset
 *      Purpose:
 *              Reset a task's IPC state to protect it when
 *              it enters an elevated security context. The
 *              task name port can remain the same - since
 *              it represents no specific privilege.
 *      Conditions:
 *              Nothing locked.  The task must be suspended.
 *              (Or the current thread must be in the task.)
 */

void
ipc_task_reset(
        task_t          task)
{
        ipc_port_t old_kport, new_kport;
        ipc_port_t old_sself;
        ipc_port_t old_exc_actions[EXC_TYPES_COUNT];
        int i;

#if CONFIG_MACF
        /* Fresh label to unset credentials in existing labels. */
        struct label *unset_label = mac_exc_create_label();
#endif

        new_kport = ipc_port_alloc_kernel();
        if (new_kport == IP_NULL) {
                panic("ipc_task_reset");
        }

        itk_lock(task);

        old_kport = task->itk_self;

        if (old_kport == IP_NULL) {
                /* the task is already terminated (can this happen?) */
                itk_unlock(task);
                ipc_port_dealloc_kernel(new_kport);
#if CONFIG_MACF
                mac_exc_free_label(unset_label);
#endif
                return;
        }

        task->itk_self = new_kport;
        old_sself = task->itk_sself;
        task->itk_sself = ipc_port_make_send(new_kport);

        /* Set the old kport to IKOT_NONE and update the exec token while under the port lock */
        ip_lock(old_kport);
        ipc_kobject_set_atomically(old_kport, IKO_NULL, IKOT_NONE);
        task->exec_token += 1;
        ip_unlock(old_kport);

        ipc_kobject_set(new_kport, (ipc_kobject_t) task, IKOT_TASK);

        for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; i++) {
                old_exc_actions[i] = IP_NULL;

                if (i == EXC_CORPSE_NOTIFY && task_corpse_pending_report(task)) {
                        continue;
                }

                if (!task->exc_actions[i].privileged) {
#if CONFIG_MACF
                        mac_exc_update_action_label(task->exc_actions + i, unset_label);
#endif
                        old_exc_actions[i] = task->exc_actions[i].port;
                        task->exc_actions[i].port = IP_NULL;
                }
        }/* for */

        if (IP_VALID(task->itk_debug_control)) {
                ipc_port_release_send(task->itk_debug_control);
        }
        task->itk_debug_control = IP_NULL;

        itk_unlock(task);

#if CONFIG_MACF
        mac_exc_free_label(unset_label);
#endif

        /* release the naked send rights */

        if (IP_VALID(old_sself)) {
                ipc_port_release_send(old_sself);
        }

        for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; i++) {
                if (IP_VALID(old_exc_actions[i])) {
                        ipc_port_release_send(old_exc_actions[i]);
                }
        }/* for */

        /* destroy the kernel port */
        ipc_port_dealloc_kernel(old_kport);
}

/*
 *      Routine:        ipc_thread_init
 *      Purpose:
 *              Initialize a thread's IPC state.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_thread_init(
        thread_t        thread)
{
        ipc_port_t      kport;

        kport = ipc_port_alloc_kernel();
        if (kport == IP_NULL) {
                panic("ipc_thread_init");
        }

        thread->ith_self = kport;
        thread->ith_sself = ipc_port_make_send(kport);
        thread->ith_special_reply_port = NULL;
        thread->exc_actions = NULL;

        ipc_kobject_set(kport, (ipc_kobject_t)thread, IKOT_THREAD);

#if IMPORTANCE_INHERITANCE
        thread->ith_assertions = 0;
#endif

        ipc_kmsg_queue_init(&thread->ith_messages);

        thread->ith_rpc_reply = IP_NULL;
}

void
ipc_thread_init_exc_actions(
        thread_t        thread)
{
        assert(thread->exc_actions == NULL);

        thread->exc_actions = kalloc(sizeof(struct exception_action) * EXC_TYPES_COUNT);
        bzero(thread->exc_actions, sizeof(struct exception_action) * EXC_TYPES_COUNT);

#if CONFIG_MACF
        for (size_t i = 0; i < EXC_TYPES_COUNT; ++i) {
                mac_exc_associate_action_label(thread->exc_actions + i, mac_exc_create_label());
        }
#endif
}

void
ipc_thread_destroy_exc_actions(
        thread_t        thread)
{
        if (thread->exc_actions != NULL) {
#if CONFIG_MACF
                for (size_t i = 0; i < EXC_TYPES_COUNT; ++i) {
                        mac_exc_free_action_label(thread->exc_actions + i);
                }
#endif

                kfree(thread->exc_actions,
                    sizeof(struct exception_action) * EXC_TYPES_COUNT);
                thread->exc_actions = NULL;
        }
}

void
ipc_thread_disable(
        thread_t        thread)
{
        ipc_port_t      kport = thread->ith_self;

        if (kport != IP_NULL) {
                ipc_kobject_set(kport, IKO_NULL, IKOT_NONE);
        }
}

/*
 *      Routine:        ipc_thread_terminate
 *      Purpose:
 *              Clean up and destroy a thread's IPC state.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_thread_terminate(
        thread_t        thread)
{
        ipc_port_t      kport = thread->ith_self;

        if (kport != IP_NULL) {
                int                     i;

                if (IP_VALID(thread->ith_sself)) {
                        ipc_port_release_send(thread->ith_sself);
                }

                thread->ith_sself = thread->ith_self = IP_NULL;

                if (thread->exc_actions != NULL) {
                        for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; ++i) {
                                if (IP_VALID(thread->exc_actions[i].port)) {
                                        ipc_port_release_send(thread->exc_actions[i].port);
                                }
                        }
                        ipc_thread_destroy_exc_actions(thread);
                }

                ipc_port_dealloc_kernel(kport);
        }

#if IMPORTANCE_INHERITANCE
        assert(thread->ith_assertions == 0);
#endif

        /* unbind the thread special reply port */
        if (IP_VALID(thread->ith_special_reply_port)) {
                ipc_port_unbind_special_reply_port(thread, TRUE);
        }

        assert(ipc_kmsg_queue_empty(&thread->ith_messages));

        if (thread->ith_rpc_reply != IP_NULL) {
                ipc_port_dealloc_reply(thread->ith_rpc_reply);
        }

        thread->ith_rpc_reply = IP_NULL;
}

/*
 *      Routine:        ipc_thread_reset
 *      Purpose:
 *              Reset the IPC state for a given Mach thread when
 *              its task enters an elevated security context.
 *              Both the thread port and its exception ports have
 *              to be reset.  Its RPC reply port cannot have any
 *              rights outstanding, so it should be fine.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_thread_reset(
        thread_t        thread)
{
        ipc_port_t old_kport, new_kport;
        ipc_port_t old_sself;
        ipc_port_t old_exc_actions[EXC_TYPES_COUNT];
        boolean_t  has_old_exc_actions = FALSE;
        int                i;

#if CONFIG_MACF
        struct label *new_label = mac_exc_create_label();
#endif

        new_kport = ipc_port_alloc_kernel();
        if (new_kport == IP_NULL) {
                panic("ipc_task_reset");
        }

        thread_mtx_lock(thread);

        old_kport = thread->ith_self;

        if (old_kport == IP_NULL && thread->inspection == FALSE) {
                /* the  is already terminated (can this happen?) */
                thread_mtx_unlock(thread);
                ipc_port_dealloc_kernel(new_kport);
#if CONFIG_MACF
                mac_exc_free_label(new_label);
#endif
                return;
        }

        thread->ith_self = new_kport;
        old_sself = thread->ith_sself;
        thread->ith_sself = ipc_port_make_send(new_kport);
        if (old_kport != IP_NULL) {
                ipc_kobject_set(old_kport, IKO_NULL, IKOT_NONE);
        }
        ipc_kobject_set(new_kport, (ipc_kobject_t) thread, IKOT_THREAD);

        /*
         * Only ports that were set by root-owned processes
         * (privileged ports) should survive
         */
        if (thread->exc_actions != NULL) {
                has_old_exc_actions = TRUE;
                for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; i++) {
                        if (thread->exc_actions[i].privileged) {
                                old_exc_actions[i] = IP_NULL;
                        } else {
#if CONFIG_MACF
                                mac_exc_update_action_label(thread->exc_actions + i, new_label);
#endif
                                old_exc_actions[i] = thread->exc_actions[i].port;
                                thread->exc_actions[i].port = IP_NULL;
                        }
                }
        }

        thread_mtx_unlock(thread);

#if CONFIG_MACF
        mac_exc_free_label(new_label);
#endif

        /* release the naked send rights */

        if (IP_VALID(old_sself)) {
                ipc_port_release_send(old_sself);
        }

        if (has_old_exc_actions) {
                for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; i++) {
                        ipc_port_release_send(old_exc_actions[i]);
                }
        }

        /* destroy the kernel port */
        if (old_kport != IP_NULL) {
                ipc_port_dealloc_kernel(old_kport);
        }

        /* unbind the thread special reply port */
        if (IP_VALID(thread->ith_special_reply_port)) {
                ipc_port_unbind_special_reply_port(thread, TRUE);
        }
}

/*
 *      Routine:        retrieve_task_self_fast
 *      Purpose:
 *              Optimized version of retrieve_task_self,
 *              that only works for the current task.
 *
 *              Return a send right (possibly null/dead)
 *              for the task's user-visible self port.
 *      Conditions:
 *              Nothing locked.
 */

ipc_port_t
retrieve_task_self_fast(
        task_t          task)
{
        ipc_port_t port;

        assert(task == current_task());

        itk_lock(task);
        assert(task->itk_self != IP_NULL);

        if ((port = task->itk_sself) == task->itk_self) {
                /* no interposing */

                ip_lock(port);
                assert(ip_active(port));
                ip_reference(port);
                port->ip_srights++;
                ip_unlock(port);
        } else {
                port = ipc_port_copy_send(port);
        }
        itk_unlock(task);

        return port;
}

/*
 *      Routine:        retrieve_thread_self_fast
 *      Purpose:
 *              Return a send right (possibly null/dead)
 *              for the thread's user-visible self port.
 *
 *              Only works for the current thread.
 *
 *      Conditions:
 *              Nothing locked.
 */

ipc_port_t
retrieve_thread_self_fast(
        thread_t                thread)
{
        ipc_port_t port;

        assert(thread == current_thread());

        thread_mtx_lock(thread);

        assert(thread->ith_self != IP_NULL);

        if ((port = thread->ith_sself) == thread->ith_self) {
                /* no interposing */

                ip_lock(port);
                assert(ip_active(port));
                ip_reference(port);
                port->ip_srights++;
                ip_unlock(port);
        } else {
                port = ipc_port_copy_send(port);
        }

        thread_mtx_unlock(thread);

        return port;
}

/*
 *      Routine:        task_self_trap [mach trap]
 *      Purpose:
 *              Give the caller send rights for his own task port.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_PORT_NULL if there are any resource failures
 *              or other errors.
 */

mach_port_name_t
task_self_trap(
        __unused struct task_self_trap_args *args)
{
        task_t task = current_task();
        ipc_port_t sright;
        mach_port_name_t name;

        sright = retrieve_task_self_fast(task);
        name = ipc_port_copyout_send(sright, task->itk_space);
        return name;
}

/*
 *      Routine:        thread_self_trap [mach trap]
 *      Purpose:
 *              Give the caller send rights for his own thread port.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_PORT_NULL if there are any resource failures
 *              or other errors.
 */

mach_port_name_t
thread_self_trap(
        __unused struct thread_self_trap_args *args)
{
        thread_t  thread = current_thread();
        task_t task = thread->task;
        ipc_port_t sright;
        mach_port_name_t name;

        sright = retrieve_thread_self_fast(thread);
        name = ipc_port_copyout_send(sright, task->itk_space);
        return name;
}

/*
 *      Routine:        mach_reply_port [mach trap]
 *      Purpose:
 *              Allocate a port for the caller.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_PORT_NULL if there are any resource failures
 *              or other errors.
 */

mach_port_name_t
mach_reply_port(
        __unused struct mach_reply_port_args *args)
{
        ipc_port_t port;
        mach_port_name_t name;
        kern_return_t kr;

        kr = ipc_port_alloc(current_task()->itk_space, &name, &port);
        if (kr == KERN_SUCCESS) {
                ip_unlock(port);
        } else {
                name = MACH_PORT_NULL;
        }
        return name;
}

/*
 *      Routine:        thread_get_special_reply_port [mach trap]
 *      Purpose:
 *              Allocate a special reply port for the calling thread.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              mach_port_name_t: send right & receive right for special reply port.
 *              MACH_PORT_NULL if there are any resource failures
 *              or other errors.
 */

mach_port_name_t
thread_get_special_reply_port(
        __unused struct thread_get_special_reply_port_args *args)
{
        ipc_port_t port;
        mach_port_name_t name;
        mach_port_name_t send_name;
        kern_return_t kr;
        thread_t thread = current_thread();

        /* unbind the thread special reply port */
        if (IP_VALID(thread->ith_special_reply_port)) {
                kr = ipc_port_unbind_special_reply_port(thread, TRUE);
                if (kr != KERN_SUCCESS) {
                        return MACH_PORT_NULL;
                }
        }

        kr = ipc_port_alloc(current_task()->itk_space, &name, &port);
        if (kr == KERN_SUCCESS) {
                ipc_port_bind_special_reply_port_locked(port);

                /* Make a send right and insert it in the space at specified name */
                ipc_port_make_send_locked(port);
                ip_unlock(port);
                send_name = ipc_port_copyout_name_send(port, current_task()->itk_space, name);
                /*
                 * If insertion of send right failed, userland is doing something bad, error out.
                 * The space was marked inactive or the receive right just inserted above at the
                 * given name was moved, in either case do not try to deallocate the receive right.
                 */
                if (send_name == MACH_PORT_NULL || send_name == MACH_PORT_DEAD) {
                        if (IP_VALID(thread->ith_special_reply_port)) {
                                ipc_port_unbind_special_reply_port(thread, TRUE);
                        }
                        name = MACH_PORT_NULL;
                }
        } else {
                name = MACH_PORT_NULL;
        }
        return name;
}

/*
 *      Routine:        ipc_port_bind_special_reply_port_locked
 *      Purpose:
 *              Bind the given port to current thread as a special reply port.
 *      Conditions:
 *              Port locked.
 *      Returns:
 *              None.
 */

static void
ipc_port_bind_special_reply_port_locked(
        ipc_port_t port)
{
        thread_t thread = current_thread();
        assert(thread->ith_special_reply_port == NULL);

        ip_reference(port);
        thread->ith_special_reply_port = port;
        port->ip_specialreply = 1;
        port->ip_sync_link_state = PORT_SYNC_LINK_ANY;

        reset_ip_srp_bits(port);
}

/*
 *      Routine:        ipc_port_unbind_special_reply_port
 *      Purpose:
 *              Unbind the thread's special reply port.
 *              If the special port has threads waiting on turnstile,
 *              update it's inheritor.
 *      Condition:
 *              Nothing locked.
 *      Returns:
 *              None.
 */
static kern_return_t
ipc_port_unbind_special_reply_port(
        thread_t thread,
        boolean_t unbind_active_port)
{
        ipc_port_t special_reply_port = thread->ith_special_reply_port;

        ip_lock(special_reply_port);

        /* Return error if port active and unbind_active_port set to FALSE */
        if (unbind_active_port == FALSE && ip_active(special_reply_port)) {
                ip_unlock(special_reply_port);
                return KERN_FAILURE;
        }

        thread->ith_special_reply_port = NULL;
        ipc_port_adjust_special_reply_port_locked(special_reply_port, NULL,
            IPC_PORT_ADJUST_SR_CLEAR_SPECIAL_REPLY, FALSE);
        /* port unlocked */

        ip_release(special_reply_port);
        return KERN_SUCCESS;
}

/*
 *      Routine:        thread_get_special_port [kernel call]
 *      Purpose:
 *              Clones a send right for one of the thread's
 *              special ports.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              KERN_SUCCESS            Extracted a send right.
 *              KERN_INVALID_ARGUMENT   The thread is null.
 *              KERN_FAILURE            The thread is dead.
 *              KERN_INVALID_ARGUMENT   Invalid special port.
 */

kern_return_t
thread_get_special_port(
        thread_t                thread,
        int                             which,
        ipc_port_t              *portp)
{
        kern_return_t   result = KERN_SUCCESS;
        ipc_port_t              *whichp;

        if (thread == THREAD_NULL) {
                return KERN_INVALID_ARGUMENT;
        }

        switch (which) {
        case THREAD_KERNEL_PORT:
                whichp = &thread->ith_sself;
                break;

        default:
                return KERN_INVALID_ARGUMENT;
        }

        thread_mtx_lock(thread);

        if (thread->active) {
                *portp = ipc_port_copy_send(*whichp);
        } else {
                result = KERN_FAILURE;
        }

        thread_mtx_unlock(thread);

        return result;
}

/*
 *      Routine:        thread_set_special_port [kernel call]
 *      Purpose:
 *              Changes one of the thread's special ports,
 *              setting it to the supplied send right.
 *      Conditions:
 *              Nothing locked.  If successful, consumes
 *              the supplied send right.
 *      Returns:
 *              KERN_SUCCESS            Changed the special port.
 *              KERN_INVALID_ARGUMENT   The thread is null.
 *              KERN_FAILURE            The thread is dead.
 *              KERN_INVALID_ARGUMENT   Invalid special port.
 */

kern_return_t
thread_set_special_port(
        thread_t                thread,
        int                     which,
        ipc_port_t      port)
{
        kern_return_t   result = KERN_SUCCESS;
        ipc_port_t              *whichp, old = IP_NULL;

        if (thread == THREAD_NULL) {
                return KERN_INVALID_ARGUMENT;
        }

        switch (which) {
        case THREAD_KERNEL_PORT:
                whichp = &thread->ith_sself;
                break;

        default:
                return KERN_INVALID_ARGUMENT;
        }

        thread_mtx_lock(thread);

        if (thread->active) {
                old = *whichp;
                *whichp = port;
        } else {
                result = KERN_FAILURE;
        }

        thread_mtx_unlock(thread);

        if (IP_VALID(old)) {
                ipc_port_release_send(old);
        }

        return result;
}

/*
 *      Routine:        task_get_special_port [kernel call]
 *      Purpose:
 *              Clones a send right for one of the task's
 *              special ports.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              KERN_SUCCESS            Extracted a send right.
 *              KERN_INVALID_ARGUMENT   The task is null.
 *              KERN_FAILURE            The task/space is dead.
 *              KERN_INVALID_ARGUMENT   Invalid special port.
 */

kern_return_t
task_get_special_port(
        task_t          task,
        int             which,
        ipc_port_t      *portp)
{
        ipc_port_t port;

        if (task == TASK_NULL) {
                return KERN_INVALID_ARGUMENT;
        }

        itk_lock(task);
        if (task->itk_self == IP_NULL) {
                itk_unlock(task);
                return KERN_FAILURE;
        }

        switch (which) {
        case TASK_KERNEL_PORT:
                port = ipc_port_copy_send(task->itk_sself);
                break;

        case TASK_NAME_PORT:
                port = ipc_port_make_send(task->itk_nself);
                break;

        case TASK_HOST_PORT:
                port = ipc_port_copy_send(task->itk_host);
                break;

        case TASK_BOOTSTRAP_PORT:
                port = ipc_port_copy_send(task->itk_bootstrap);
                break;

        case TASK_SEATBELT_PORT:
                port = ipc_port_copy_send(task->itk_seatbelt);
                break;

        case TASK_ACCESS_PORT:
                port = ipc_port_copy_send(task->itk_task_access);
                break;

        case TASK_DEBUG_CONTROL_PORT:
                port = ipc_port_copy_send(task->itk_debug_control);
                break;

        default:
                itk_unlock(task);
                return KERN_INVALID_ARGUMENT;
        }
        itk_unlock(task);

        *portp = port;
        return KERN_SUCCESS;
}

/*
 *      Routine:        task_set_special_port [kernel call]
 *      Purpose:
 *              Changes one of the task's special ports,
 *              setting it to the supplied send right.
 *      Conditions:
 *              Nothing locked.  If successful, consumes
 *              the supplied send right.
 *      Returns:
 *              KERN_SUCCESS            Changed the special port.
 *              KERN_INVALID_ARGUMENT   The task is null.
 *              KERN_FAILURE            The task/space is dead.
 *              KERN_INVALID_ARGUMENT   Invalid special port.
 *              KERN_NO_ACCESS          Attempted overwrite of seatbelt port.
 */

kern_return_t
task_set_special_port(
        task_t          task,
        int             which,
        ipc_port_t      port)
{
        ipc_port_t *whichp;
        ipc_port_t old;

        if (task == TASK_NULL) {
                return KERN_INVALID_ARGUMENT;
        }

        switch (which) {
        case TASK_KERNEL_PORT:
                whichp = &task->itk_sself;
                break;

        case TASK_HOST_PORT:
                whichp = &task->itk_host;
                break;

        case TASK_BOOTSTRAP_PORT:
                whichp = &task->itk_bootstrap;
                break;

        case TASK_SEATBELT_PORT:
                whichp = &task->itk_seatbelt;
                break;

        case TASK_ACCESS_PORT:
                whichp = &task->itk_task_access;
                break;

        case TASK_DEBUG_CONTROL_PORT:
                whichp = &task->itk_debug_control;
                break;

        default:
                return KERN_INVALID_ARGUMENT;
        }/* switch */

        itk_lock(task);
        if (task->itk_self == IP_NULL) {
                itk_unlock(task);
                return KERN_FAILURE;
        }

        /* do not allow overwrite of seatbelt or task access ports */
        if ((TASK_SEATBELT_PORT == which || TASK_ACCESS_PORT == which)
            && IP_VALID(*whichp)) {
                itk_unlock(task);
                return KERN_NO_ACCESS;
        }

        old = *whichp;
        *whichp = port;
        itk_unlock(task);

        if (IP_VALID(old)) {
                ipc_port_release_send(old);
        }
        return KERN_SUCCESS;
}


/*
 *      Routine:        mach_ports_register [kernel call]
 *      Purpose:
 *              Stash a handful of port send rights in the task.
 *              Child tasks will inherit these rights, but they
 *              must use mach_ports_lookup to acquire them.
 *
 *              The rights are supplied in a (wired) kalloc'd segment.
 *              Rights which aren't supplied are assumed to be null.
 *      Conditions:
 *              Nothing locked.  If successful, consumes
 *              the supplied rights and memory.
 *      Returns:
 *              KERN_SUCCESS            Stashed the port rights.
 *              KERN_INVALID_ARGUMENT   The task is null.
 *              KERN_INVALID_ARGUMENT   The task is dead.
 *              KERN_INVALID_ARGUMENT   The memory param is null.
 *              KERN_INVALID_ARGUMENT   Too many port rights supplied.
 */

kern_return_t
mach_ports_register(
        task_t                  task,
        mach_port_array_t       memory,
        mach_msg_type_number_t  portsCnt)
{
        ipc_port_t ports[TASK_PORT_REGISTER_MAX];
        unsigned int i;

        if ((task == TASK_NULL) ||
            (portsCnt > TASK_PORT_REGISTER_MAX) ||
            (portsCnt && memory == NULL)) {
                return KERN_INVALID_ARGUMENT;
        }

        /*
         *      Pad the port rights with nulls.
         */

        for (i = 0; i < portsCnt; i++) {
                ports[i] = memory[i];
        }
        for (; i < TASK_PORT_REGISTER_MAX; i++) {
                ports[i] = IP_NULL;
        }

        itk_lock(task);
        if (task->itk_self == IP_NULL) {
                itk_unlock(task);
                return KERN_INVALID_ARGUMENT;
        }

        /*
         *      Replace the old send rights with the new.
         *      Release the old rights after unlocking.
         */

        for (i = 0; i < TASK_PORT_REGISTER_MAX; i++) {
                ipc_port_t old;

                old = task->itk_registered[i];
                task->itk_registered[i] = ports[i];
                ports[i] = old;
        }

        itk_unlock(task);

        for (i = 0; i < TASK_PORT_REGISTER_MAX; i++) {
                if (IP_VALID(ports[i])) {
                        ipc_port_release_send(ports[i]);
                }
        }

        /*
         *      Now that the operation is known to be successful,
         *      we can free the memory.
         */

        if (portsCnt != 0) {
                kfree(memory,
                    (vm_size_t) (portsCnt * sizeof(mach_port_t)));
        }

        return KERN_SUCCESS;
}

/*
 *      Routine:        mach_ports_lookup [kernel call]
 *      Purpose:
 *              Retrieves (clones) the stashed port send rights.
 *      Conditions:
 *              Nothing locked.  If successful, the caller gets
 *              rights and memory.
 *      Returns:
 *              KERN_SUCCESS            Retrieved the send rights.
 *              KERN_INVALID_ARGUMENT   The task is null.
 *              KERN_INVALID_ARGUMENT   The task is dead.
 *              KERN_RESOURCE_SHORTAGE  Couldn't allocate memory.
 */

kern_return_t
mach_ports_lookup(
        task_t                  task,
        mach_port_array_t       *portsp,
        mach_msg_type_number_t  *portsCnt)
{
        void  *memory;
        vm_size_t size;
        ipc_port_t *ports;
        int i;

        if (task == TASK_NULL) {
                return KERN_INVALID_ARGUMENT;
        }

        size = (vm_size_t) (TASK_PORT_REGISTER_MAX * sizeof(ipc_port_t));

        memory = kalloc(size);
        if (memory == 0) {
                return KERN_RESOURCE_SHORTAGE;
        }

        itk_lock(task);
        if (task->itk_self == IP_NULL) {
                itk_unlock(task);

                kfree(memory, size);
                return KERN_INVALID_ARGUMENT;
        }

        ports = (ipc_port_t *) memory;

        /*
         *      Clone port rights.  Because kalloc'd memory
         *      is wired, we won't fault while holding the task lock.
         */

        for (i = 0; i < TASK_PORT_REGISTER_MAX; i++) {
                ports[i] = ipc_port_copy_send(task->itk_registered[i]);
        }

        itk_unlock(task);

        *portsp = (mach_port_array_t) ports;
        *portsCnt = TASK_PORT_REGISTER_MAX;
        return KERN_SUCCESS;
}

kern_return_t
task_conversion_eval(task_t caller, task_t victim)
{
        /*
         * Tasks are allowed to resolve their own task ports, and the kernel is
         * allowed to resolve anyone's task port.
         */
        if (caller == kernel_task) {
                return KERN_SUCCESS;
        }

        if (caller == victim) {
                return KERN_SUCCESS;
        }

        /*
         * Only the kernel can can resolve the kernel's task port. We've established
         * by this point that the caller is not kernel_task.
         */
        if (victim == TASK_NULL || victim == kernel_task) {
                return KERN_INVALID_SECURITY;
        }

#if CONFIG_EMBEDDED
        /*
         * On embedded platforms, only a platform binary can resolve the task port
         * of another platform binary.
         */
        if ((victim->t_flags & TF_PLATFORM) && !(caller->t_flags & TF_PLATFORM)) {
#if SECURE_KERNEL
                return KERN_INVALID_SECURITY;
#else
                if (cs_relax_platform_task_ports) {
                        return KERN_SUCCESS;
                } else {
                        return KERN_INVALID_SECURITY;
                }
#endif /* SECURE_KERNEL */
        }
#endif /* CONFIG_EMBEDDED */

        return KERN_SUCCESS;
}

/*
 *      Routine: convert_port_to_locked_task
 *      Purpose:
 *              Internal helper routine to convert from a port to a locked
 *              task.  Used by several routines that try to convert from a
 *              task port to a reference on some task related object.
 *      Conditions:
 *              Nothing locked, blocking OK.
 */
task_t
convert_port_to_locked_task(ipc_port_t port)
{
        int try_failed_count = 0;

        while (IP_VALID(port)) {
                task_t ct = current_task();
                task_t task;

                ip_lock(port);
                if (!ip_active(port) || (ip_kotype(port) != IKOT_TASK)) {
                        ip_unlock(port);
                        return TASK_NULL;
                }
                task = (task_t) port->ip_kobject;
                assert(task != TASK_NULL);

                if (task_conversion_eval(ct, task)) {
                        ip_unlock(port);
                        return TASK_NULL;
                }

                /*
                 * Normal lock ordering puts task_lock() before ip_lock().
                 * Attempt out-of-order locking here.
                 */
                if (task_lock_try(task)) {
                        ip_unlock(port);
                        return task;
                }
                try_failed_count++;

                ip_unlock(port);
                mutex_pause(try_failed_count);
        }
        return TASK_NULL;
}

/*
 *      Routine: convert_port_to_locked_task_inspect
 *      Purpose:
 *              Internal helper routine to convert from a port to a locked
 *              task inspect right. Used by internal routines that try to convert from a
 *              task inspect port to a reference on some task related object.
 *      Conditions:
 *              Nothing locked, blocking OK.
 */
task_inspect_t
convert_port_to_locked_task_inspect(ipc_port_t port)
{
        int try_failed_count = 0;

        while (IP_VALID(port)) {
                task_inspect_t task;

                ip_lock(port);
                if (!ip_active(port) || (ip_kotype(port) != IKOT_TASK)) {
                        ip_unlock(port);
                        return TASK_INSPECT_NULL;
                }
                task = (task_inspect_t)port->ip_kobject;
                assert(task != TASK_INSPECT_NULL);
                /*
                 * Normal lock ordering puts task_lock() before ip_lock().
                 * Attempt out-of-order locking here.
                 */
                if (task_lock_try((task_t)task)) {
                        ip_unlock(port);
                        return task;
                }
                try_failed_count++;

                ip_unlock(port);
                mutex_pause(try_failed_count);
        }
        return TASK_INSPECT_NULL;
}


/*
 *      Routine:        convert_port_to_task
 *      Purpose:
 *              Convert from a port to a task.
 *              Doesn't consume the port ref; produces a task ref,
 *              which may be null.
 *      Conditions:
 *              Nothing locked.
 */
task_t
convert_port_to_task(
        ipc_port_t              port)
{
        return convert_port_to_task_with_exec_token(port, NULL);
}

/*
 *      Routine:        convert_port_to_task_with_exec_token
 *      Purpose:
 *              Convert from a port to a task and return
 *              the exec token stored in the task.
 *              Doesn't consume the port ref; produces a task ref,
 *              which may be null.
 *      Conditions:
 *              Nothing locked.
 */
task_t
convert_port_to_task_with_exec_token(
        ipc_port_t              port,
        uint32_t                *exec_token)
{
        task_t          task = TASK_NULL;

        if (IP_VALID(port)) {
                ip_lock(port);

                if (ip_active(port) &&
                    ip_kotype(port) == IKOT_TASK) {
                        task_t ct = current_task();
                        task = (task_t)port->ip_kobject;
                        assert(task != TASK_NULL);

                        if (task_conversion_eval(ct, task)) {
                                ip_unlock(port);
                                return TASK_NULL;
                        }

                        if (exec_token) {
                                *exec_token = task->exec_token;
                        }
                        task_reference_internal(task);
                }

                ip_unlock(port);
        }

        return task;
}

/*
 *      Routine:        convert_port_to_task_name
 *      Purpose:
 *              Convert from a port to a task name.
 *              Doesn't consume the port ref; produces a task name ref,
 *              which may be null.
 *      Conditions:
 *              Nothing locked.
 */
task_name_t
convert_port_to_task_name(
        ipc_port_t              port)
{
        task_name_t             task = TASK_NULL;

        if (IP_VALID(port)) {
                ip_lock(port);

                if (ip_active(port) &&
                    (ip_kotype(port) == IKOT_TASK ||
                    ip_kotype(port) == IKOT_TASK_NAME)) {
                        task = (task_name_t)port->ip_kobject;
                        assert(task != TASK_NAME_NULL);

                        task_reference_internal(task);
                }

                ip_unlock(port);
        }

        return task;
}

/*
 *      Routine:        convert_port_to_task_inspect
 *      Purpose:
 *              Convert from a port to a task inspection right
 *              Doesn't consume the port ref; produces a task ref,
 *              which may be null.
 *      Conditions:
 *              Nothing locked.
 */
task_inspect_t
convert_port_to_task_inspect(
        ipc_port_t              port)
{
        task_inspect_t task = TASK_INSPECT_NULL;

        if (IP_VALID(port)) {
                ip_lock(port);

                if (ip_active(port) &&
                    ip_kotype(port) == IKOT_TASK) {
                        task = (task_inspect_t)port->ip_kobject;
                        assert(task != TASK_INSPECT_NULL);

                        task_reference_internal(task);
                }

                ip_unlock(port);
        }

        return task;
}

/*
 *      Routine:        convert_port_to_task_suspension_token
 *      Purpose:
 *              Convert from a port to a task suspension token.
 *              Doesn't consume the port ref; produces a suspension token ref,
 *              which may be null.
 *      Conditions:
 *              Nothing locked.
 */
task_suspension_token_t
convert_port_to_task_suspension_token(
        ipc_port_t              port)
{
        task_suspension_token_t         task = TASK_NULL;

        if (IP_VALID(port)) {
                ip_lock(port);

                if (ip_active(port) &&
                    ip_kotype(port) == IKOT_TASK_RESUME) {
                        task = (task_suspension_token_t)port->ip_kobject;
                        assert(task != TASK_NULL);

                        task_reference_internal(task);
                }

                ip_unlock(port);
        }

        return task;
}

/*
 *      Routine:        convert_port_to_space
 *      Purpose:
 *              Convert from a port to a space.
 *              Doesn't consume the port ref; produces a space ref,
 *              which may be null.
 *      Conditions:
 *              Nothing locked.
 */
ipc_space_t
convert_port_to_space(
        ipc_port_t      port)
{
        ipc_space_t space;
        task_t task;

        task = convert_port_to_locked_task(port);

        if (task == TASK_NULL) {
                return IPC_SPACE_NULL;
        }

        if (!task->active) {
                task_unlock(task);
                return IPC_SPACE_NULL;
        }

        space = task->itk_space;
        is_reference(space);
        task_unlock(task);
        return space;
}

/*
 *      Routine:        convert_port_to_space_inspect
 *      Purpose:
 *              Convert from a port to a space inspect right.
 *              Doesn't consume the port ref; produces a space inspect ref,
 *              which may be null.
 *      Conditions:
 *              Nothing locked.
 */
ipc_space_inspect_t
convert_port_to_space_inspect(
        ipc_port_t      port)
{
        ipc_space_inspect_t space;
        task_inspect_t task;

        task = convert_port_to_locked_task_inspect(port);

        if (task == TASK_INSPECT_NULL) {
                return IPC_SPACE_INSPECT_NULL;
        }

        if (!task->active) {
                task_unlock(task);
                return IPC_SPACE_INSPECT_NULL;
        }

        space = (ipc_space_inspect_t)task->itk_space;
        is_reference((ipc_space_t)space);
        task_unlock((task_t)task);
        return space;
}

/*
 *      Routine:        convert_port_to_map
 *      Purpose:
 *              Convert from a port to a map.
 *              Doesn't consume the port ref; produces a map ref,
 *              which may be null.
 *      Conditions:
 *              Nothing locked.
 */

vm_map_t
convert_port_to_map(
        ipc_port_t      port)
{
        task_t task;
        vm_map_t map;

        task = convert_port_to_locked_task(port);

        if (task == TASK_NULL) {
                return VM_MAP_NULL;
        }

        if (!task->active) {
                task_unlock(task);
                return VM_MAP_NULL;
        }

        map = task->map;
        vm_map_reference_swap(map);
        task_unlock(task);
        return map;
}


/*
 *      Routine:        convert_port_to_thread
 *      Purpose:
 *              Convert from a port to a thread.
 *              Doesn't consume the port ref; produces an thread ref,
 *              which may be null.
 *      Conditions:
 *              Nothing locked.
 */

thread_t
convert_port_to_thread(
        ipc_port_t              port)
{
        thread_t        thread = THREAD_NULL;

        if (IP_VALID(port)) {
                ip_lock(port);

                if (ip_active(port) &&
                    ip_kotype(port) == IKOT_THREAD) {
                        thread = (thread_t)port->ip_kobject;
                        assert(thread != THREAD_NULL);

                        /* Use task conversion rules for thread control conversions */
                        if (task_conversion_eval(current_task(), thread->task) != KERN_SUCCESS) {
                                ip_unlock(port);
                                return THREAD_NULL;
                        }

                        thread_reference_internal(thread);
                }

                ip_unlock(port);
        }

        return thread;
}

/*
 *      Routine:        convert_port_to_thread_inspect
 *      Purpose:
 *              Convert from a port to a thread inspection right
 *              Doesn't consume the port ref; produces a thread ref,
 *              which may be null.
 *      Conditions:
 *              Nothing locked.
 */
thread_inspect_t
convert_port_to_thread_inspect(
        ipc_port_t              port)
{
        thread_inspect_t thread = THREAD_INSPECT_NULL;

        if (IP_VALID(port)) {
                ip_lock(port);

                if (ip_active(port) &&
                    ip_kotype(port) == IKOT_THREAD) {
                        thread = (thread_inspect_t)port->ip_kobject;
                        assert(thread != THREAD_INSPECT_NULL);
                        thread_reference_internal((thread_t)thread);
                }
                ip_unlock(port);
        }

        return thread;
}

/*
 *      Routine:        convert_thread_inspect_to_port
 *      Purpose:
 *              Convert from a thread inspect reference to a port.
 *              Consumes a thread ref;
 *              As we never export thread inspect ports, always
 *              creates a NULL port.
 *      Conditions:
 *              Nothing locked.
 */

ipc_port_t
convert_thread_inspect_to_port(thread_inspect_t thread)
{
        thread_deallocate(thread);
        return IP_NULL;
}


/*
 *      Routine:        port_name_to_thread
 *      Purpose:
 *              Convert from a port name to an thread reference
 *              A name of MACH_PORT_NULL is valid for the null thread.
 *      Conditions:
 *              Nothing locked.
 *
 *      TODO: Could this be faster if it were ipc_port_translate_send based, like thread_switch?
 *            We could avoid extra lock/unlock and extra ref operations on the port.
 */
thread_t
port_name_to_thread(
        mach_port_name_t        name)
{
        thread_t        thread = THREAD_NULL;
        ipc_port_t      kport;

        if (MACH_PORT_VALID(name)) {
                if (ipc_object_copyin(current_space(), name,
                    MACH_MSG_TYPE_COPY_SEND,
                    (ipc_object_t *)&kport) != KERN_SUCCESS) {
                        return THREAD_NULL;
                }

                thread = convert_port_to_thread(kport);

                if (IP_VALID(kport)) {
                        ipc_port_release_send(kport);
                }
        }

        return thread;
}

task_t
port_name_to_task(
        mach_port_name_t name)
{
        ipc_port_t kern_port;
        kern_return_t kr;
        task_t task = TASK_NULL;

        if (MACH_PORT_VALID(name)) {
                kr = ipc_object_copyin(current_space(), name,
                    MACH_MSG_TYPE_COPY_SEND,
                    (ipc_object_t *) &kern_port);
                if (kr != KERN_SUCCESS) {
                        return TASK_NULL;
                }

                task = convert_port_to_task(kern_port);

                if (IP_VALID(kern_port)) {
                        ipc_port_release_send(kern_port);
                }
        }
        return task;
}

task_inspect_t
port_name_to_task_inspect(
        mach_port_name_t name)
{
        ipc_port_t kern_port;
        kern_return_t kr;
        task_inspect_t ti = TASK_INSPECT_NULL;

        if (MACH_PORT_VALID(name)) {
                kr = ipc_object_copyin(current_space(), name,
                    MACH_MSG_TYPE_COPY_SEND,
                    (ipc_object_t *)&kern_port);
                if (kr != KERN_SUCCESS) {
                        return TASK_NULL;
                }

                ti = convert_port_to_task_inspect(kern_port);

                if (IP_VALID(kern_port)) {
                        ipc_port_release_send(kern_port);
                }
        }
        return ti;
}

/*
 *      Routine:        port_name_to_host
 *      Purpose:
 *              Convert from a port name to a host pointer.
 *              NOTE: This does _not_ return a +1 reference to the host_t
 *      Conditions:
 *              Nothing locked.
 */
host_t
port_name_to_host(
        mach_port_name_t name)
{
        host_t host = HOST_NULL;
        kern_return_t kr;
        ipc_port_t port;

        if (MACH_PORT_VALID(name)) {
                kr = ipc_port_translate_send(current_space(), name, &port);
                if (kr == KERN_SUCCESS) {
                        host = convert_port_to_host(port);
                        ip_unlock(port);
                }
        }
        return host;
}

/*
 *      Routine:        convert_task_to_port
 *      Purpose:
 *              Convert from a task to a port.
 *              Consumes a task ref; produces a naked send right
 *              which may be invalid.
 *      Conditions:
 *              Nothing locked.
 */

ipc_port_t
convert_task_to_port(
        task_t          task)
{
        ipc_port_t port;

        itk_lock(task);

        if (task->itk_self != IP_NULL) {
                port = ipc_port_make_send(task->itk_self);
        } else {
                port = IP_NULL;
        }

        itk_unlock(task);

        task_deallocate(task);
        return port;
}

/*
 *      Routine:        convert_task_inspect_to_port
 *      Purpose:
 *              Convert from a task inspect reference to a port.
 *              Consumes a task ref;
 *              As we never export task inspect ports, always
 *              creates a NULL port.
 *      Conditions:
 *              Nothing locked.
 */
ipc_port_t
convert_task_inspect_to_port(
        task_inspect_t          task)
{
        task_deallocate(task);

        return IP_NULL;
}

/*
 *      Routine:        convert_task_suspend_token_to_port
 *      Purpose:
 *              Convert from a task suspension token to a port.
 *              Consumes a task suspension token ref; produces a naked send-once right
 *              which may be invalid.
 *      Conditions:
 *              Nothing locked.
 */
ipc_port_t
convert_task_suspension_token_to_port(
        task_suspension_token_t         task)
{
        ipc_port_t port;

        task_lock(task);
        if (task->active) {
                if (task->itk_resume == IP_NULL) {
                        task->itk_resume = ipc_port_alloc_kernel();
                        if (!IP_VALID(task->itk_resume)) {
                                panic("failed to create resume port");
                        }

                        ipc_kobject_set(task->itk_resume, (ipc_kobject_t) task, IKOT_TASK_RESUME);
                }

                /*
                 * Create a send-once right for each instance of a direct user-called
                 * task_suspend2 call. Each time one of these send-once rights is abandoned,
                 * the notification handler will resume the target task.
                 */
                port = ipc_port_make_sonce(task->itk_resume);
                assert(IP_VALID(port));
        } else {
                port = IP_NULL;
        }

        task_unlock(task);
        task_suspension_token_deallocate(task);

        return port;
}


/*
 *      Routine:        convert_task_name_to_port
 *      Purpose:
 *              Convert from a task name ref to a port.
 *              Consumes a task name ref; produces a naked send right
 *              which may be invalid.
 *      Conditions:
 *              Nothing locked.
 */

ipc_port_t
convert_task_name_to_port(
        task_name_t             task_name)
{
        ipc_port_t port;

        itk_lock(task_name);
        if (task_name->itk_nself != IP_NULL) {
                port = ipc_port_make_send(task_name->itk_nself);
        } else {
                port = IP_NULL;
        }
        itk_unlock(task_name);

        task_name_deallocate(task_name);
        return port;
}

/*
 *      Routine:        convert_thread_to_port
 *      Purpose:
 *              Convert from a thread to a port.
 *              Consumes an thread ref; produces a naked send right
 *              which may be invalid.
 *      Conditions:
 *              Nothing locked.
 */

ipc_port_t
convert_thread_to_port(
        thread_t                thread)
{
        ipc_port_t              port;

        thread_mtx_lock(thread);

        if (thread->ith_self != IP_NULL) {
                port = ipc_port_make_send(thread->ith_self);
        } else {
                port = IP_NULL;
        }

        thread_mtx_unlock(thread);

        thread_deallocate(thread);

        return port;
}

/*
 *      Routine:        space_deallocate
 *      Purpose:
 *              Deallocate a space ref produced by convert_port_to_space.
 *      Conditions:
 *              Nothing locked.
 */

void
space_deallocate(
        ipc_space_t     space)
{
        if (space != IS_NULL) {
                is_release(space);
        }
}

/*
 *      Routine:        space_inspect_deallocate
 *      Purpose:
 *              Deallocate a space inspect ref produced by convert_port_to_space_inspect.
 *      Conditions:
 *              Nothing locked.
 */

void
space_inspect_deallocate(
        ipc_space_inspect_t     space)
{
        if (space != IS_INSPECT_NULL) {
                is_release((ipc_space_t)space);
        }
}

/*
 *      Routine:        thread/task_set_exception_ports [kernel call]
 *      Purpose:
 *                      Sets the thread/task exception port, flavor and
 *                      behavior for the exception types specified by the mask.
 *                      There will be one send right per exception per valid
 *                      port.
 *      Conditions:
 *              Nothing locked.  If successful, consumes
 *              the supplied send right.
 *      Returns:
 *              KERN_SUCCESS            Changed the special port.
 *              KERN_INVALID_ARGUMENT   The thread is null,
 *                                      Illegal mask bit set.
 *                                      Illegal exception behavior
 *              KERN_FAILURE            The thread is dead.
 */

kern_return_t
thread_set_exception_ports(
        thread_t                                thread,
        exception_mask_t                exception_mask,
        ipc_port_t                              new_port,
        exception_behavior_t    new_behavior,
        thread_state_flavor_t   new_flavor)
{
        ipc_port_t              old_port[EXC_TYPES_COUNT];
        boolean_t privileged = current_task()->sec_token.val[0] == 0;
        register int    i;

#if CONFIG_MACF
        struct label *new_label;
#endif

        if (thread == THREAD_NULL) {
                return KERN_INVALID_ARGUMENT;
        }

        if (exception_mask & ~EXC_MASK_VALID) {
                return KERN_INVALID_ARGUMENT;
        }

        if (IP_VALID(new_port)) {
                switch (new_behavior & ~MACH_EXCEPTION_CODES) {
                case EXCEPTION_DEFAULT:
                case EXCEPTION_STATE:
                case EXCEPTION_STATE_IDENTITY:
                        break;

                default:
                        return KERN_INVALID_ARGUMENT;
                }
        }

        /*
         * Check the validity of the thread_state_flavor by calling the
         * VALID_THREAD_STATE_FLAVOR architecture dependent macro defined in
         * osfmk/mach/ARCHITECTURE/thread_status.h
         */
        if (new_flavor != 0 && !VALID_THREAD_STATE_FLAVOR(new_flavor)) {
                return KERN_INVALID_ARGUMENT;
        }

#if CONFIG_MACF
        new_label = mac_exc_create_label_for_current_proc();
#endif

        thread_mtx_lock(thread);

        if (!thread->active) {
                thread_mtx_unlock(thread);

                return KERN_FAILURE;
        }

        if (thread->exc_actions == NULL) {
                ipc_thread_init_exc_actions(thread);
        }
        for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; ++i) {
                if ((exception_mask & (1 << i))
#if CONFIG_MACF
                    && mac_exc_update_action_label(&thread->exc_actions[i], new_label) == 0
#endif
                    ) {
                        old_port[i] = thread->exc_actions[i].port;
                        thread->exc_actions[i].port = ipc_port_copy_send(new_port);
                        thread->exc_actions[i].behavior = new_behavior;
                        thread->exc_actions[i].flavor = new_flavor;
                        thread->exc_actions[i].privileged = privileged;
                } else {
                        old_port[i] = IP_NULL;
                }
        }

        thread_mtx_unlock(thread);

#if CONFIG_MACF
        mac_exc_free_label(new_label);
#endif

        for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; ++i) {
                if (IP_VALID(old_port[i])) {
                        ipc_port_release_send(old_port[i]);
                }
        }

        if (IP_VALID(new_port)) {        /* consume send right */
                ipc_port_release_send(new_port);
        }

        return KERN_SUCCESS;
}

kern_return_t
task_set_exception_ports(
        task_t                                  task,
        exception_mask_t                exception_mask,
        ipc_port_t                              new_port,
        exception_behavior_t    new_behavior,
        thread_state_flavor_t   new_flavor)
{
        ipc_port_t              old_port[EXC_TYPES_COUNT];
        boolean_t privileged = current_task()->sec_token.val[0] == 0;
        register int    i;

#if CONFIG_MACF
        struct label *new_label;
#endif

        if (task == TASK_NULL) {
                return KERN_INVALID_ARGUMENT;
        }

        if (exception_mask & ~EXC_MASK_VALID) {
                return KERN_INVALID_ARGUMENT;
        }

        if (IP_VALID(new_port)) {
                switch (new_behavior & ~MACH_EXCEPTION_CODES) {
                case EXCEPTION_DEFAULT:
                case EXCEPTION_STATE:
                case EXCEPTION_STATE_IDENTITY:
                        break;

                default:
                        return KERN_INVALID_ARGUMENT;
                }
        }

        /*
         * Check the validity of the thread_state_flavor by calling the
         * VALID_THREAD_STATE_FLAVOR architecture dependent macro defined in
         * osfmk/mach/ARCHITECTURE/thread_status.h
         */
        if (new_flavor != 0 && !VALID_THREAD_STATE_FLAVOR(new_flavor)) {
                return KERN_INVALID_ARGUMENT;
        }

#if CONFIG_MACF
        new_label = mac_exc_create_label_for_current_proc();
#endif

        itk_lock(task);

        if (task->itk_self == IP_NULL) {
                itk_unlock(task);

                return KERN_FAILURE;
        }

        for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; ++i) {
                if ((exception_mask & (1 << i))
#if CONFIG_MACF
                    && mac_exc_update_action_label(&task->exc_actions[i], new_label) == 0
#endif
                    ) {
                        old_port[i] = task->exc_actions[i].port;
                        task->exc_actions[i].port =
                            ipc_port_copy_send(new_port);
                        task->exc_actions[i].behavior = new_behavior;
                        task->exc_actions[i].flavor = new_flavor;
                        task->exc_actions[i].privileged = privileged;
                } else {
                        old_port[i] = IP_NULL;
                }
        }

        itk_unlock(task);

#if CONFIG_MACF
        mac_exc_free_label(new_label);
#endif

        for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; ++i) {
                if (IP_VALID(old_port[i])) {
                        ipc_port_release_send(old_port[i]);
                }
        }

        if (IP_VALID(new_port)) {        /* consume send right */
                ipc_port_release_send(new_port);
        }

        return KERN_SUCCESS;
}

/*
 *      Routine:        thread/task_swap_exception_ports [kernel call]
 *      Purpose:
 *                      Sets the thread/task exception port, flavor and
 *                      behavior for the exception types specified by the
 *                      mask.
 *
 *                      The old ports, behavior and flavors are returned
 *                      Count specifies the array sizes on input and
 *                      the number of returned ports etc. on output.  The
 *                      arrays must be large enough to hold all the returned
 *                      data, MIG returnes an error otherwise.  The masks
 *                      array specifies the corresponding exception type(s).
 *
 *      Conditions:
 *              Nothing locked.  If successful, consumes
 *              the supplied send right.
 *
 *              Returns upto [in} CountCnt elements.
 *      Returns:
 *              KERN_SUCCESS            Changed the special port.
 *              KERN_INVALID_ARGUMENT   The thread is null,
 *                                      Illegal mask bit set.
 *                                      Illegal exception behavior
 *              KERN_FAILURE            The thread is dead.
 */

kern_return_t
thread_swap_exception_ports(
        thread_t                                        thread,
        exception_mask_t                        exception_mask,
        ipc_port_t                                      new_port,
        exception_behavior_t            new_behavior,
        thread_state_flavor_t           new_flavor,
        exception_mask_array_t          masks,
        mach_msg_type_number_t          *CountCnt,
        exception_port_array_t          ports,
        exception_behavior_array_t      behaviors,
        thread_state_flavor_array_t     flavors)
{
        ipc_port_t              old_port[EXC_TYPES_COUNT];
        boolean_t privileged = current_task()->sec_token.val[0] == 0;
        unsigned int    i, j, count;

#if CONFIG_MACF
        struct label *new_label;
#endif

        if (thread == THREAD_NULL) {
                return KERN_INVALID_ARGUMENT;
        }

        if (exception_mask & ~EXC_MASK_VALID) {
                return KERN_INVALID_ARGUMENT;
        }

        if (IP_VALID(new_port)) {
                switch (new_behavior & ~MACH_EXCEPTION_CODES) {
                case EXCEPTION_DEFAULT:
                case EXCEPTION_STATE:
                case EXCEPTION_STATE_IDENTITY:
                        break;

                default:
                        return KERN_INVALID_ARGUMENT;
                }
        }

        if (new_flavor != 0 && !VALID_THREAD_STATE_FLAVOR(new_flavor)) {
                return KERN_INVALID_ARGUMENT;
        }

#if CONFIG_MACF
        new_label = mac_exc_create_label_for_current_proc();
#endif

        thread_mtx_lock(thread);

        if (!thread->active) {
                thread_mtx_unlock(thread);

                return KERN_FAILURE;
        }

        if (thread->exc_actions == NULL) {
                ipc_thread_init_exc_actions(thread);
        }

        assert(EXC_TYPES_COUNT > FIRST_EXCEPTION);
        for (count = 0, i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT && count < *CountCnt; ++i) {
                if ((exception_mask & (1 << i))
#if CONFIG_MACF
                    && mac_exc_update_action_label(&thread->exc_actions[i], new_label) == 0
#endif
                    ) {
                        for (j = 0; j < count; ++j) {
                                /*
                                 * search for an identical entry, if found
                                 * set corresponding mask for this exception.
                                 */
                                if (thread->exc_actions[i].port == ports[j] &&
                                    thread->exc_actions[i].behavior == behaviors[j] &&
                                    thread->exc_actions[i].flavor == flavors[j]) {
                                        masks[j] |= (1 << i);
                                        break;
                                }
                        }

                        if (j == count) {
                                masks[j] = (1 << i);
                                ports[j] = ipc_port_copy_send(thread->exc_actions[i].port);

                                behaviors[j] = thread->exc_actions[i].behavior;
                                flavors[j] = thread->exc_actions[i].flavor;
                                ++count;
                        }

                        old_port[i] = thread->exc_actions[i].port;
                        thread->exc_actions[i].port = ipc_port_copy_send(new_port);
                        thread->exc_actions[i].behavior = new_behavior;
                        thread->exc_actions[i].flavor = new_flavor;
                        thread->exc_actions[i].privileged = privileged;
                } else {
                        old_port[i] = IP_NULL;
                }
        }

        thread_mtx_unlock(thread);

#if CONFIG_MACF
        mac_exc_free_label(new_label);
#endif

        while (--i >= FIRST_EXCEPTION) {
                if (IP_VALID(old_port[i])) {
                        ipc_port_release_send(old_port[i]);
                }
        }

        if (IP_VALID(new_port)) {        /* consume send right */
                ipc_port_release_send(new_port);
        }

        *CountCnt = count;

        return KERN_SUCCESS;
}

kern_return_t
task_swap_exception_ports(
        task_t                                          task,
        exception_mask_t                        exception_mask,
        ipc_port_t                                      new_port,
        exception_behavior_t            new_behavior,
        thread_state_flavor_t           new_flavor,
        exception_mask_array_t          masks,
        mach_msg_type_number_t          *CountCnt,
        exception_port_array_t          ports,
        exception_behavior_array_t      behaviors,
        thread_state_flavor_array_t     flavors)
{
        ipc_port_t              old_port[EXC_TYPES_COUNT];
        boolean_t privileged = current_task()->sec_token.val[0] == 0;
        unsigned int    i, j, count;

#if CONFIG_MACF
        struct label *new_label;
#endif

        if (task == TASK_NULL) {
                return KERN_INVALID_ARGUMENT;
        }

        if (exception_mask & ~EXC_MASK_VALID) {
                return KERN_INVALID_ARGUMENT;
        }

        if (IP_VALID(new_port)) {
                switch (new_behavior & ~MACH_EXCEPTION_CODES) {
                case EXCEPTION_DEFAULT:
                case EXCEPTION_STATE:
                case EXCEPTION_STATE_IDENTITY:
                        break;

                default:
                        return KERN_INVALID_ARGUMENT;
                }
        }

        if (new_flavor != 0 && !VALID_THREAD_STATE_FLAVOR(new_flavor)) {
                return KERN_INVALID_ARGUMENT;
        }

#if CONFIG_MACF
        new_label = mac_exc_create_label_for_current_proc();
#endif

        itk_lock(task);

        if (task->itk_self == IP_NULL) {
                itk_unlock(task);

                return KERN_FAILURE;
        }

        assert(EXC_TYPES_COUNT > FIRST_EXCEPTION);
        for (count = 0, i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT && count < *CountCnt; ++i) {
                if ((exception_mask & (1 << i))
#if CONFIG_MACF
                    && mac_exc_update_action_label(&task->exc_actions[i], new_label) == 0
#endif
                    ) {
                        for (j = 0; j < count; j++) {
                                /*
                                 * search for an identical entry, if found
                                 * set corresponding mask for this exception.
                                 */
                                if (task->exc_actions[i].port == ports[j] &&
                                    task->exc_actions[i].behavior == behaviors[j] &&
                                    task->exc_actions[i].flavor == flavors[j]) {
                                        masks[j] |= (1 << i);
                                        break;
                                }
                        }

                        if (j == count) {
                                masks[j] = (1 << i);
                                ports[j] = ipc_port_copy_send(task->exc_actions[i].port);
                                behaviors[j] = task->exc_actions[i].behavior;
                                flavors[j] = task->exc_actions[i].flavor;
                                ++count;
                        }

                        old_port[i] = task->exc_actions[i].port;

                        task->exc_actions[i].port =     ipc_port_copy_send(new_port);
                        task->exc_actions[i].behavior = new_behavior;
                        task->exc_actions[i].flavor = new_flavor;
                        task->exc_actions[i].privileged = privileged;
                } else {
                        old_port[i] = IP_NULL;
                }
        }

        itk_unlock(task);

#if CONFIG_MACF
        mac_exc_free_label(new_label);
#endif

        while (--i >= FIRST_EXCEPTION) {
                if (IP_VALID(old_port[i])) {
                        ipc_port_release_send(old_port[i]);
                }
        }

        if (IP_VALID(new_port)) {        /* consume send right */
                ipc_port_release_send(new_port);
        }

        *CountCnt = count;

        return KERN_SUCCESS;
}

/*
 *      Routine:        thread/task_get_exception_ports [kernel call]
 *      Purpose:
 *              Clones a send right for each of the thread/task's exception
 *              ports specified in the mask and returns the behaviour
 *              and flavor of said port.
 *
 *              Returns upto [in} CountCnt elements.
 *
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              KERN_SUCCESS            Extracted a send right.
 *              KERN_INVALID_ARGUMENT   The thread is null,
 *                                      Invalid special port,
 *                                      Illegal mask bit set.
 *              KERN_FAILURE            The thread is dead.
 */

kern_return_t
thread_get_exception_ports(
        thread_t                                        thread,
        exception_mask_t                        exception_mask,
        exception_mask_array_t          masks,
        mach_msg_type_number_t          *CountCnt,
        exception_port_array_t          ports,
        exception_behavior_array_t      behaviors,
        thread_state_flavor_array_t     flavors)
{
        unsigned int    i, j, count;

        if (thread == THREAD_NULL) {
                return KERN_INVALID_ARGUMENT;
        }

        if (exception_mask & ~EXC_MASK_VALID) {
                return KERN_INVALID_ARGUMENT;
        }

        thread_mtx_lock(thread);

        if (!thread->active) {
                thread_mtx_unlock(thread);

                return KERN_FAILURE;
        }

        count = 0;

        if (thread->exc_actions == NULL) {
                goto done;
        }

        for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; ++i) {
                if (exception_mask & (1 << i)) {
                        for (j = 0; j < count; ++j) {
                                /*
                                 * search for an identical entry, if found
                                 * set corresponding mask for this exception.
                                 */
                                if (thread->exc_actions[i].port == ports[j] &&
                                    thread->exc_actions[i].behavior == behaviors[j] &&
                                    thread->exc_actions[i].flavor == flavors[j]) {
                                        masks[j] |= (1 << i);
                                        break;
                                }
                        }

                        if (j == count) {
                                masks[j] = (1 << i);
                                ports[j] = ipc_port_copy_send(thread->exc_actions[i].port);
                                behaviors[j] = thread->exc_actions[i].behavior;
                                flavors[j] = thread->exc_actions[i].flavor;
                                ++count;
                                if (count >= *CountCnt) {
                                        break;
                                }
                        }
                }
        }

done:
        thread_mtx_unlock(thread);

        *CountCnt = count;

        return KERN_SUCCESS;
}

kern_return_t
task_get_exception_ports(
        task_t                                          task,
        exception_mask_t                        exception_mask,
        exception_mask_array_t          masks,
        mach_msg_type_number_t          *CountCnt,
        exception_port_array_t          ports,
        exception_behavior_array_t      behaviors,
        thread_state_flavor_array_t     flavors)
{
        unsigned int    i, j, count;

        if (task == TASK_NULL) {
                return KERN_INVALID_ARGUMENT;
        }

        if (exception_mask & ~EXC_MASK_VALID) {
                return KERN_INVALID_ARGUMENT;
        }

        itk_lock(task);

        if (task->itk_self == IP_NULL) {
                itk_unlock(task);

                return KERN_FAILURE;
        }

        count = 0;

        for (i = FIRST_EXCEPTION; i < EXC_TYPES_COUNT; ++i) {
                if (exception_mask & (1 << i)) {
                        for (j = 0; j < count; ++j) {
                                /*
                                 * search for an identical entry, if found
                                 * set corresponding mask for this exception.
                                 */
                                if (task->exc_actions[i].port == ports[j] &&
                                    task->exc_actions[i].behavior == behaviors[j] &&
                                    task->exc_actions[i].flavor == flavors[j]) {
                                        masks[j] |= (1 << i);
                                        break;
                                }
                        }

                        if (j == count) {
                                masks[j] = (1 << i);
                                ports[j] = ipc_port_copy_send(task->exc_actions[i].port);
                                behaviors[j] = task->exc_actions[i].behavior;
                                flavors[j] = task->exc_actions[i].flavor;
                                ++count;
                                if (count > *CountCnt) {
                                        break;
                                }
                        }
                }
        }

        itk_unlock(task);

        *CountCnt = count;

        return KERN_SUCCESS;
}