xnu-3248.40.184.tar.gz

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

/*
 * Copyright (c) 2013 Apple Computer, 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@
 */

#include <kern/kern_types.h>
#include <mach/mach_types.h>
#include <mach/boolean.h>

#include <kern/coalition.h>
#include <kern/host.h>
#include <kern/kalloc.h>
#include <kern/ledger.h>
#include <kern/mach_param.h> /* for TASK_CHUNK */
#include <kern/task.h>
#include <kern/zalloc.h>

#include <libkern/OSAtomic.h>

#include <mach/coalition_notification_server.h>
#include <mach/host_priv.h>
#include <mach/host_special_ports.h>

#include <sys/errno.h>

/*
 * BSD interface functions
 */
int coalitions_get_list(int type, struct procinfo_coalinfo *coal_list, int list_sz);
boolean_t coalition_is_leader(task_t task, int coal_type, coalition_t *coal);
task_t coalition_get_leader(coalition_t coal);
int coalition_get_task_count(coalition_t coal);
uint64_t coalition_get_page_count(coalition_t coal, int *ntasks);
int coalition_get_pid_list(coalition_t coal, uint32_t rolemask, int sort_order,
                                  int *pid_list, int list_sz);

/* defined in task.c */
extern ledger_template_t task_ledger_template;

/*
 * Coalition zone needs limits. We expect there will be as many coalitions as
 * tasks (same order of magnitude), so use the task zone's limits.
 * */
#define CONFIG_COALITION_MAX CONFIG_TASK_MAX
#define COALITION_CHUNK TASK_CHUNK

int unrestrict_coalition_syscalls;

lck_attr_t coalitions_lck_attr;
lck_grp_t coalitions_lck_grp;
lck_grp_attr_t coalitions_lck_grp_attr;

/* coalitions_list_lock protects coalition_count, coalitions queue, next_coalition_id. */
decl_lck_mtx_data(static,coalitions_list_lock);
static uint64_t coalition_count;
static uint64_t coalition_next_id = 1;
static queue_head_t coalitions_q;

coalition_t init_coalition[COALITION_NUM_TYPES];

zone_t coalition_zone;

static const char *coal_type_str(int type)
{
        switch(type) {
        case COALITION_TYPE_RESOURCE:
                return "RESOURCE";
        case COALITION_TYPE_JETSAM:
                return "JETSAM";
        default:
                return "<unknown>";
        }
}

struct coalition_type {
        int type;
        int has_default;
        /*
         * init
         * pre-condition: coalition just allocated (unlocked), unreferenced,
         *                type field set
         */
        kern_return_t (*init)(coalition_t coal, boolean_t privileged);

        /*
         * dealloc
         * pre-condition: coalition unlocked
         * pre-condition: coalition refcount=0, active_count=0,
         *                termrequested=1, terminated=1, reaped=1
         */
        void          (*dealloc)(coalition_t coal);

        /*
         * adopt_task
         * pre-condition: coalition locked
         * pre-condition: coalition !repead and !terminated
         */
        kern_return_t (*adopt_task)(coalition_t coal, task_t task);

        /*
         * remove_task
         * pre-condition: coalition locked
         * pre-condition: task has been removed from coalition's task list
         */
        kern_return_t (*remove_task)(coalition_t coal, task_t task);

        /*
         * set_taskrole
         * pre-condition: coalition locked
         * pre-condition: task added to coalition's task list,
         *                active_count >= 1 (at least the given task is active)
         */
        kern_return_t (*set_taskrole)(coalition_t coal, task_t task, int role);

        /*
         * get_taskrole
         * pre-condition: coalition locked
         * pre-condition: task added to coalition's task list,
         *                active_count >= 1 (at least the given task is active)
         */
        int (*get_taskrole)(coalition_t coal, task_t task);

        /*
         * iterate_tasks
         * pre-condition: coalition locked
         */
        void (*iterate_tasks)(coalition_t coal, void *ctx, void (*callback)(coalition_t, void *, task_t));
};

/*
 * COALITION_TYPE_RESOURCE
 */

static kern_return_t i_coal_resource_init(coalition_t coal, boolean_t privileged);
static void          i_coal_resource_dealloc(coalition_t coal);
static kern_return_t i_coal_resource_adopt_task(coalition_t coal, task_t task);
static kern_return_t i_coal_resource_remove_task(coalition_t coal, task_t task);
static kern_return_t i_coal_resource_set_taskrole(coalition_t coal,
                                                 task_t task, int role);
static int           i_coal_resource_get_taskrole(coalition_t coal, task_t task);
static void          i_coal_resource_iterate_tasks(coalition_t coal, void *ctx,
                                                   void (*callback)(coalition_t, void *, task_t));

struct i_resource_coalition {
        ledger_t ledger;
        uint64_t bytesread;
        uint64_t byteswritten;
        uint64_t gpu_time;
        uint64_t logical_immediate_writes;
        uint64_t logical_deferred_writes;
        uint64_t logical_invalidated_writes;
        uint64_t logical_metadata_writes;

        uint64_t task_count;      /* tasks that have started in this coalition */
        uint64_t dead_task_count; /* tasks that have exited in this coalition;
                                     subtract from task_count to get count
                                     of "active" tasks */
        /*
         * Count the length of time this coalition had at least one active task.
         * This can be a 'denominator' to turn e.g. cpu_time to %cpu.
         * */
        uint64_t last_became_nonempty_time;
        uint64_t time_nonempty;

        queue_head_t tasks;         /* List of active tasks in the coalition */
};

/*
 * COALITION_TYPE_JETSAM
 */

static kern_return_t i_coal_jetsam_init(coalition_t coal, boolean_t privileged);
static void          i_coal_jetsam_dealloc(coalition_t coal);
static kern_return_t i_coal_jetsam_adopt_task(coalition_t coal, task_t task);
static kern_return_t i_coal_jetsam_remove_task(coalition_t coal, task_t task);
static kern_return_t i_coal_jetsam_set_taskrole(coalition_t coal,
                                               task_t task, int role);
static int           i_coal_jetsam_get_taskrole(coalition_t coal, task_t task);
static void          i_coal_jetsam_iterate_tasks(coalition_t coal, void *ctx,
                                                 void (*callback)(coalition_t, void *, task_t));

struct i_jetsam_coalition {
        task_t       leader;
        queue_head_t extensions;
        queue_head_t services;
        queue_head_t other;
};


/*
 * main coalition structure
 */
struct coalition {
        uint64_t id;                /* monotonically increasing */
        uint32_t type;
        uint32_t ref_count;         /* Number of references to the memory containing this struct */
        uint32_t active_count;      /* Number of members of (tasks in) the
                                       coalition, plus vouchers referring
                                       to the coalition */
        uint32_t focal_task_count;   /* Number of TASK_FOREGROUND_APPLICATION tasks in the coalition */
        uint32_t nonfocal_task_count; /* Number of TASK_BACKGROUND_APPLICATION tasks in the coalition */

        /* coalition flags */
        uint32_t privileged : 1;    /* Members of this coalition may create
                                       and manage coalitions and may posix_spawn
                                       processes into selected coalitions */
        /* ast? */
        /* voucher */
        uint32_t termrequested : 1; /* launchd has requested termination when coalition becomes empty */
        uint32_t terminated : 1;    /* coalition became empty and spawns are now forbidden */
        uint32_t reaped : 1;        /* reaped, invisible to userspace, but waiting for ref_count to go to zero */
        uint32_t notified : 1;      /* no-more-processes notification was sent via special port */
#if defined(DEVELOPMENT) || defined(DEBUG)
        uint32_t should_notify : 1; /* should this coalition send notifications (default: yes) */
#endif

        queue_chain_t coalitions;   /* global list of coalitions */

        decl_lck_mtx_data(,lock)    /* Coalition lock. */

        /* put coalition type-specific structures here */
        union {
                struct i_resource_coalition  r;
                struct i_jetsam_coalition    j;
        };
};

/*
 * register different coalition types:
 * these must be kept in the order specified in coalition.h
 */
static const struct coalition_type
s_coalition_types[COALITION_NUM_TYPES] = {
        {
                COALITION_TYPE_RESOURCE,
                1,
                i_coal_resource_init,
                i_coal_resource_dealloc,
                i_coal_resource_adopt_task,
                i_coal_resource_remove_task,
                i_coal_resource_set_taskrole,
                i_coal_resource_get_taskrole,
                i_coal_resource_iterate_tasks,
        },
        {
                COALITION_TYPE_JETSAM,
                1,
                i_coal_jetsam_init,
                i_coal_jetsam_dealloc,
                i_coal_jetsam_adopt_task,
                i_coal_jetsam_remove_task,
                i_coal_jetsam_set_taskrole,
                i_coal_jetsam_get_taskrole,
                i_coal_jetsam_iterate_tasks,
        },
};

#define coal_call(coal, func, ...) \
        (s_coalition_types[(coal)->type].func)(coal, ## __VA_ARGS__)


#define coalition_lock(c) do{ lck_mtx_lock(&c->lock); }while(0)
#define coalition_unlock(c) do{ lck_mtx_unlock(&c->lock); }while(0)

static void
coalition_notify_user(uint64_t id, uint32_t flags)
{
        mach_port_t user_port;
        kern_return_t kr;

        kr = host_get_coalition_port(host_priv_self(), &user_port);
        if ((kr != KERN_SUCCESS) || !IPC_PORT_VALID(user_port)) {
                return;
        }

        coalition_notification(user_port, id, flags);
}

/*
 *
 * COALITION_TYPE_RESOURCE
 *
 */
static kern_return_t
i_coal_resource_init(coalition_t coal, boolean_t privileged)
{
        (void)privileged;
        assert(coal && coal->type == COALITION_TYPE_RESOURCE);
        coal->r.ledger = ledger_instantiate(task_ledger_template,
                                            LEDGER_CREATE_ACTIVE_ENTRIES);
        if (coal->r.ledger == NULL)
                return KERN_RESOURCE_SHORTAGE;

        queue_init(&coal->r.tasks);

        return KERN_SUCCESS;
}

static void
i_coal_resource_dealloc(coalition_t coal)
{
        assert(coal && coal->type == COALITION_TYPE_RESOURCE);
        ledger_dereference(coal->r.ledger);
}

static kern_return_t
i_coal_resource_adopt_task(coalition_t coal, task_t task)
{
        struct i_resource_coalition *cr;

        assert(coal && coal->type == COALITION_TYPE_RESOURCE);
        assert(queue_empty(&task->task_coalition[COALITION_TYPE_RESOURCE]));

        cr = &coal->r;
        cr->task_count++;

        if (cr->task_count < cr->dead_task_count) {
                panic("%s: coalition %p id:%llu type:%s task_count(%llu) < dead_task_count(%llu)",
                      __func__, coal, coal->id, coal_type_str(coal->type),
                      cr->task_count, cr->dead_task_count);
        }

        /* If moving from 0->1 active tasks */
        if (cr->task_count - cr->dead_task_count == 1) {
                cr->last_became_nonempty_time = mach_absolute_time();
        }

        /* put the task on the coalition's list of tasks */
        enqueue_tail(&cr->tasks, &task->task_coalition[COALITION_TYPE_RESOURCE]);

        coal_dbg("Added PID:%d to id:%llu, task_count:%llu, dead_count:%llu, nonempty_time:%llu",
                 task_pid(task), coal->id, cr->task_count, cr->dead_task_count,
                 cr->last_became_nonempty_time);

        return KERN_SUCCESS;
}

static kern_return_t
i_coal_resource_remove_task(coalition_t coal, task_t task)
{
        struct i_resource_coalition *cr;

        assert(coal && coal->type == COALITION_TYPE_RESOURCE);
        assert(task->coalition[COALITION_TYPE_RESOURCE] == coal);
        assert(!queue_empty(&task->task_coalition[COALITION_TYPE_RESOURCE]));

        /*
         * handle resource coalition accounting rollup for dead tasks
         */
        cr = &coal->r;

        cr->dead_task_count++;

        if (cr->task_count < cr->dead_task_count) {
                panic("%s: coalition %p id:%llu type:%s task_count(%llu) < dead_task_count(%llu)",
                      __func__, coal, coal->id, coal_type_str(coal->type), cr->task_count, cr->dead_task_count);
        }

        /* If moving from 1->0 active tasks */
        if (cr->task_count - cr->dead_task_count == 0) {
                uint64_t last_time_nonempty = mach_absolute_time() - cr->last_became_nonempty_time;
                cr->last_became_nonempty_time = 0;
                cr->time_nonempty += last_time_nonempty;
        }

        ledger_rollup(cr->ledger, task->ledger);
        cr->bytesread += task->task_io_stats->disk_reads.size;
        cr->byteswritten += task->task_io_stats->total_io.size - task->task_io_stats->disk_reads.size;
        cr->gpu_time += task_gpu_utilisation(task);
        cr->logical_immediate_writes += task->task_immediate_writes;    
        cr->logical_deferred_writes += task->task_deferred_writes;
        cr->logical_invalidated_writes += task->task_invalidated_writes;
        cr->logical_metadata_writes += task->task_metadata_writes;

        /* remove the task from the coalition's list */
        remqueue(&task->task_coalition[COALITION_TYPE_RESOURCE]);
        queue_chain_init(task->task_coalition[COALITION_TYPE_RESOURCE]);

        coal_dbg("removed PID:%d from id:%llu, task_count:%llu, dead_count:%llu",
                 task_pid(task), coal->id, cr->task_count, cr->dead_task_count);

        return KERN_SUCCESS;
}

static kern_return_t
i_coal_resource_set_taskrole(__unused coalition_t coal,
                            __unused task_t task, __unused int role)
{
        return KERN_SUCCESS;
}

static int
i_coal_resource_get_taskrole(__unused coalition_t coal, __unused task_t task)
{
        task_t t;

        assert(coal && coal->type == COALITION_TYPE_RESOURCE);

        qe_foreach_element(t, &coal->r.tasks, task_coalition[COALITION_TYPE_RESOURCE]) {
                if (t == task)
                        return COALITION_TASKROLE_UNDEF;
        }

        return -1;
}

static void
i_coal_resource_iterate_tasks(coalition_t coal, void *ctx, void (*callback)(coalition_t, void *, task_t))
{
        task_t t;
        assert(coal && coal->type == COALITION_TYPE_RESOURCE);

        qe_foreach_element(t, &coal->r.tasks, task_coalition[COALITION_TYPE_RESOURCE])
                callback(coal, ctx, t);
}

kern_return_t
coalition_resource_usage_internal(coalition_t coal, struct coalition_resource_usage *cru_out)
{
        kern_return_t kr;
        ledger_amount_t credit, debit;

        if (coal->type != COALITION_TYPE_RESOURCE)
                return KERN_INVALID_ARGUMENT;

        ledger_t sum_ledger = ledger_instantiate(task_ledger_template, LEDGER_CREATE_ACTIVE_ENTRIES);
        if (sum_ledger == LEDGER_NULL)
                return KERN_RESOURCE_SHORTAGE;

        coalition_lock(coal);

        /*
         * Start with the coalition's ledger, which holds the totals from all
         * the dead tasks.
         */
        ledger_rollup(sum_ledger, coal->r.ledger);
        uint64_t bytesread = coal->r.bytesread;
        uint64_t byteswritten = coal->r.byteswritten;
        uint64_t gpu_time = coal->r.gpu_time;
        uint64_t logical_immediate_writes = coal->r.logical_immediate_writes;
        uint64_t logical_deferred_writes = coal->r.logical_deferred_writes;
        uint64_t logical_invalidated_writes = coal->r.logical_invalidated_writes;
        uint64_t logical_metadata_writes = coal->r.logical_metadata_writes;
        int64_t cpu_time_billed_to_me = 0;
        int64_t cpu_time_billed_to_others = 0;

        kr = ledger_get_balance(sum_ledger, task_ledgers.cpu_time_billed_to_me, (int64_t *)&cpu_time_billed_to_me);
        if (kr != KERN_SUCCESS || cpu_time_billed_to_me < 0) {
#if DEVELOPMENT || DEBUG
                printf("ledger_get_balance failed or ledger negative in coalition_resource_usage_internal: %lld\n", cpu_time_billed_to_me);
#endif /* DEVELOPMENT || DEBUG */
                cpu_time_billed_to_me = 0;
        }

        kr = ledger_get_balance(sum_ledger, task_ledgers.cpu_time_billed_to_others, (int64_t *)&cpu_time_billed_to_others);
        if (kr != KERN_SUCCESS || cpu_time_billed_to_others < 0) {
#if DEVELOPMENT || DEBUG
                printf("ledger_get_balance failed or ledger negative in coalition_resource_usage_internal: %lld\n", cpu_time_billed_to_others);
#endif /* DEVELOPMENT || DEBUG */
                cpu_time_billed_to_others = 0;
        }

        /*
         * Add to that all the active tasks' ledgers. Tasks cannot deallocate
         * out from under us, since we hold the coalition lock.
         * Do not use the on-behalf of cpu time from ledger for live tasks, since
         * it will not have cpu time for active linkages between tasks.
         */
        task_t task;
        qe_foreach_element(task, &coal->r.tasks, task_coalition[COALITION_TYPE_RESOURCE]) {
                ledger_rollup(sum_ledger, task->ledger);
                bytesread += task->task_io_stats->disk_reads.size;
                byteswritten += task->task_io_stats->total_io.size - task->task_io_stats->disk_reads.size;
                gpu_time += task_gpu_utilisation(task);
                logical_immediate_writes += task->task_immediate_writes;
                logical_deferred_writes += task->task_deferred_writes;
                logical_invalidated_writes += task->task_invalidated_writes;
                logical_metadata_writes += task->task_metadata_writes;
                cpu_time_billed_to_me += (int64_t)bank_billed_time_safe(task);
                cpu_time_billed_to_others += (int64_t)bank_serviced_time_safe(task);
        }

        /* collect information from the coalition itself */
        cru_out->tasks_started = coal->r.task_count;
        cru_out->tasks_exited = coal->r.dead_task_count;

        uint64_t time_nonempty = coal->r.time_nonempty;
        uint64_t last_became_nonempty_time = coal->r.last_became_nonempty_time;

        coalition_unlock(coal);

        /* Copy the totals out of sum_ledger */
        kr = ledger_get_entries(sum_ledger, task_ledgers.cpu_time,
                        &credit, &debit);
        if (kr != KERN_SUCCESS) {
                credit = 0;
        }
        cru_out->cpu_time = credit;
        cru_out->cpu_time_billed_to_me = (uint64_t)cpu_time_billed_to_me;
        cru_out->cpu_time_billed_to_others = (uint64_t)cpu_time_billed_to_others;

        kr = ledger_get_entries(sum_ledger, task_ledgers.interrupt_wakeups,
                        &credit, &debit);
        if (kr != KERN_SUCCESS) {
                credit = 0;
        }
        cru_out->interrupt_wakeups = credit;

        kr = ledger_get_entries(sum_ledger, task_ledgers.platform_idle_wakeups,
                        &credit, &debit);
        if (kr != KERN_SUCCESS) {
                credit = 0;
        }
        cru_out->platform_idle_wakeups = credit;

        cru_out->bytesread = bytesread;
        cru_out->byteswritten = byteswritten;
        cru_out->gpu_time = gpu_time;
        cru_out->logical_immediate_writes = logical_immediate_writes;
        cru_out->logical_deferred_writes = logical_deferred_writes;
        cru_out->logical_invalidated_writes = logical_invalidated_writes;
        cru_out->logical_metadata_writes = logical_metadata_writes;

        ledger_dereference(sum_ledger);
        sum_ledger = LEDGER_NULL;

        if (last_became_nonempty_time) {
                time_nonempty += mach_absolute_time() - last_became_nonempty_time;
        }
        absolutetime_to_nanoseconds(time_nonempty, &cru_out->time_nonempty);

        return KERN_SUCCESS;
}

/*
 *
 * COALITION_TYPE_JETSAM
 *
 */
static kern_return_t
i_coal_jetsam_init(coalition_t coal, boolean_t privileged)
{
        assert(coal && coal->type == COALITION_TYPE_JETSAM);
        (void)privileged;

        coal->j.leader= TASK_NULL;
        queue_head_init(coal->j.extensions);
        queue_head_init(coal->j.services);
        queue_head_init(coal->j.other);

        return KERN_SUCCESS;
}

static void
i_coal_jetsam_dealloc(__unused coalition_t coal)
{
        assert(coal && coal->type == COALITION_TYPE_JETSAM);

        /* the coalition should be completely clear at this point */
        assert(queue_empty(&coal->j.extensions));
        assert(queue_empty(&coal->j.services));
        assert(queue_empty(&coal->j.other));
        assert(coal->j.leader == TASK_NULL);
}

static kern_return_t
i_coal_jetsam_adopt_task(coalition_t coal, task_t task)
{
        struct i_jetsam_coalition *cj;
        assert(coal && coal->type == COALITION_TYPE_JETSAM);

        cj = &coal->j;

        assert(queue_empty(&task->task_coalition[COALITION_TYPE_JETSAM]));

        /* put each task initially in the "other" list */
        enqueue_tail(&cj->other, &task->task_coalition[COALITION_TYPE_JETSAM]);
        coal_dbg("coalition %lld adopted PID:%d as UNDEF",
                 coal->id, task_pid(task));

        return KERN_SUCCESS;
}

static kern_return_t
i_coal_jetsam_remove_task(coalition_t coal, task_t task)
{
        assert(coal && coal->type == COALITION_TYPE_JETSAM);
        assert(task->coalition[COALITION_TYPE_JETSAM] == coal);

        coal_dbg("removing PID:%d from coalition id:%lld",
                 task_pid(task), coal->id);

        if (task == coal->j.leader) {
                coal->j.leader = NULL;
                coal_dbg("    PID:%d was the leader!", task_pid(task));
        } else {
                assert(!queue_empty(&task->task_coalition[COALITION_TYPE_JETSAM]));
        }

        /* remove the task from the specific coalition role queue */
        remqueue(&task->task_coalition[COALITION_TYPE_JETSAM]);
        queue_chain_init(task->task_coalition[COALITION_TYPE_RESOURCE]);

        return KERN_SUCCESS;
}

static kern_return_t
i_coal_jetsam_set_taskrole(coalition_t coal, task_t task, int role)
{
        struct i_jetsam_coalition *cj;
        queue_t q = NULL;
        assert(coal && coal->type == COALITION_TYPE_JETSAM);
        assert(task->coalition[COALITION_TYPE_JETSAM] == coal);

        cj = &coal->j;

        switch (role) {
        case COALITION_TASKROLE_LEADER:
                coal_dbg("setting PID:%d as LEADER of %lld",
                         task_pid(task), coal->id);
                if (cj->leader != TASK_NULL) {
                        /* re-queue the exiting leader onto the "other" list */
                        coal_dbg("    re-queue existing leader (%d) as OTHER",
                                 task_pid(cj->leader));
                        re_queue_tail(&cj->other, &cj->leader->task_coalition[COALITION_TYPE_JETSAM]);
                }
                /*
                 * remove the task from the "other" list
                 * (where it was put by default)
                 */
                remqueue(&task->task_coalition[COALITION_TYPE_JETSAM]);
                queue_chain_init(task->task_coalition[COALITION_TYPE_JETSAM]);

                /* set the coalition leader */
                cj->leader = task;
                break;
        case COALITION_TASKROLE_UNDEF:
                coal_dbg("setting PID:%d as UNDEF in %lld",
                         task_pid(task), coal->id);
                q = (queue_t)&cj->other;
                break;
        case COALITION_TASKROLE_XPC:
                coal_dbg("setting PID:%d as XPC in %lld",
                         task_pid(task), coal->id);
                q = (queue_t)&cj->services;
                break;
        case COALITION_TASKROLE_EXT:
                coal_dbg("setting PID:%d as EXT in %lld",
                         task_pid(task), coal->id);
                q = (queue_t)&cj->extensions;
                break;
        default:
                panic("%s: invalid role(%d) for task", __func__, role);
                return KERN_INVALID_ARGUMENT;
        }

        if (q != NULL)
                re_queue_tail(q, &task->task_coalition[COALITION_TYPE_JETSAM]);

        return KERN_SUCCESS;
}

static int
i_coal_jetsam_get_taskrole(coalition_t coal, task_t task)
{
        struct i_jetsam_coalition *cj;
        task_t t;

        assert(coal && coal->type == COALITION_TYPE_JETSAM);
        assert(task->coalition[COALITION_TYPE_JETSAM] == coal);

        cj = &coal->j;

        if (task == cj->leader)
                return COALITION_TASKROLE_LEADER;

        qe_foreach_element(t, &cj->services, task_coalition[COALITION_TYPE_JETSAM]) {
                if (t == task)
                        return COALITION_TASKROLE_XPC;
        }

        qe_foreach_element(t, &cj->extensions, task_coalition[COALITION_TYPE_JETSAM]) {
                if (t == task)
                        return COALITION_TASKROLE_EXT;
        }

        qe_foreach_element(t, &cj->other, task_coalition[COALITION_TYPE_JETSAM]) {
                if (t == task)
                        return COALITION_TASKROLE_UNDEF;
        }

        /* task not in the coalition?! */
        return -1;
}

static void
i_coal_jetsam_iterate_tasks(coalition_t coal, void *ctx, void (*callback)(coalition_t, void *, task_t))
{
        struct i_jetsam_coalition *cj;
        task_t t;

        assert(coal && coal->type == COALITION_TYPE_JETSAM);

        cj = &coal->j;

        if (cj->leader)
                callback(coal, ctx, cj->leader);

        qe_foreach_element(t, &cj->services, task_coalition[COALITION_TYPE_JETSAM])
                callback(coal, ctx, t);

        qe_foreach_element(t, &cj->extensions, task_coalition[COALITION_TYPE_JETSAM])
                callback(coal, ctx, t);

        qe_foreach_element(t, &cj->other, task_coalition[COALITION_TYPE_JETSAM])
                callback(coal, ctx, t);
}


/*
 *
 * Main Coalition implementation
 *
 */

/*
 * coalition_create_internal
 * Returns: New coalition object, referenced for the caller and unlocked.
 * Condition: coalitions_list_lock must be UNLOCKED.
 */
kern_return_t
coalition_create_internal(int type, boolean_t privileged, coalition_t *out)
{
        kern_return_t kr;
        struct coalition *new_coal;

        if (type < 0 || type > COALITION_TYPE_MAX)
                return KERN_INVALID_ARGUMENT;

        new_coal = (struct coalition *)zalloc(coalition_zone);
        if (new_coal == COALITION_NULL)
                return KERN_RESOURCE_SHORTAGE;
        bzero(new_coal, sizeof(*new_coal));

        new_coal->type = type;

        /* initialize type-specific resources */
        kr = coal_call(new_coal, init, privileged);
        if (kr != KERN_SUCCESS) {
                zfree(coalition_zone, new_coal);
                return kr;
        }

        /* One for caller, one for coalitions list */
        new_coal->ref_count = 2;

        new_coal->privileged = privileged ? TRUE : FALSE;
#if defined(DEVELOPMENT) || defined(DEBUG)
        new_coal->should_notify = 1;
#endif

        lck_mtx_init(&new_coal->lock, &coalitions_lck_grp, &coalitions_lck_attr);

        lck_mtx_lock(&coalitions_list_lock);
        new_coal->id = coalition_next_id++;
        coalition_count++;
        enqueue_tail(&coalitions_q, &new_coal->coalitions);
        lck_mtx_unlock(&coalitions_list_lock);

        coal_dbg("id:%llu, type:%s", new_coal->id, coal_type_str(new_coal->type));

        *out = new_coal;
        return KERN_SUCCESS;
}

/*
 * coalition_release
 * Condition: coalition must be UNLOCKED.
 * */
void
coalition_release(coalition_t coal)
{
        /* TODO: This can be done with atomics. */
        coalition_lock(coal);
        coal->ref_count--;

#if COALITION_DEBUG
        uint32_t rc = coal->ref_count;
        uint32_t ac = coal->active_count;
#endif /* COALITION_DEBUG */

        coal_dbg("id:%llu type:%s ref_count:%u active_count:%u%s",
                 coal->id, coal_type_str(coal->type), rc, ac,
                 rc <= 0 ? ", will deallocate now" : "");

        if (coal->ref_count > 0) {
                coalition_unlock(coal);
                return;
        }

        assert(coal->termrequested);
        assert(coal->terminated);
        assert(coal->active_count == 0);
        assert(coal->reaped);
        assert(coal->focal_task_count == 0);
        assert(coal->nonfocal_task_count == 0);

        coal_call(coal, dealloc);

        coalition_unlock(coal);

        lck_mtx_destroy(&coal->lock, &coalitions_lck_grp);

        zfree(coalition_zone, coal);
}

/*
 * coalition_find_by_id_internal
 * Returns: Coalition object with specified id, NOT referenced.
 *          If not found, returns COALITION_NULL.
 * Condition: coalitions_list_lock must be LOCKED.
 */
static coalition_t
coalition_find_by_id_internal(uint64_t coal_id)
{
        if (coal_id == 0) {
                return COALITION_NULL;
        }

        lck_mtx_assert(&coalitions_list_lock, LCK_MTX_ASSERT_OWNED);
        coalition_t coal;
        qe_foreach_element(coal, &coalitions_q, coalitions) {
                if (coal->id == coal_id) {
                        return coal;
                }
        }
        return COALITION_NULL;
}

/*
 * coalition_find_by_id
 * Returns: Coalition object with specified id, referenced.
 * Condition: coalitions_list_lock must be UNLOCKED.
 */
coalition_t
coalition_find_by_id(uint64_t cid)
{
        if (cid == 0) {
                return COALITION_NULL;
        }

        lck_mtx_lock(&coalitions_list_lock);

        coalition_t coal = coalition_find_by_id_internal(cid);
        if (coal == COALITION_NULL) {
                lck_mtx_unlock(&coalitions_list_lock);
                return COALITION_NULL;
        }

        coalition_lock(coal);

        if (coal->reaped) {
                coalition_unlock(coal);
                lck_mtx_unlock(&coalitions_list_lock);
                return COALITION_NULL;
        }

        if (coal->ref_count == 0) {
                panic("resurrecting coalition %p id:%llu type:%s, active_count:%u\n",
                                coal, coal->id, coal_type_str(coal->type), coal->active_count);
        }
        coal->ref_count++;
#if COALITION_DEBUG
        uint32_t rc = coal->ref_count;
#endif

        coalition_unlock(coal);
        lck_mtx_unlock(&coalitions_list_lock);

        coal_dbg("id:%llu type:%s ref_count:%u",
                 coal->id, coal_type_str(coal->type), rc);

        return coal;
}

/*
 * coalition_find_and_activate_by_id
 * Returns: Coalition object with specified id, referenced, and activated.
 * Condition: coalitions_list_lock must be UNLOCKED.
 * This is the function to use when putting a 'new' thing into a coalition,
 * like posix_spawn of an XPC service by launchd.
 * See also coalition_extend_active.
 */
coalition_t
coalition_find_and_activate_by_id(uint64_t cid)
{
        if (cid == 0) {
                return COALITION_NULL;
        }

        lck_mtx_lock(&coalitions_list_lock);

        coalition_t coal = coalition_find_by_id_internal(cid);
        if (coal == COALITION_NULL) {
                lck_mtx_unlock(&coalitions_list_lock);
                return COALITION_NULL;
        }

        coalition_lock(coal);

        if (coal->reaped || coal->terminated) {
                /* Too late to put something new into this coalition, it's
                 * already on its way out the door */
                coalition_unlock(coal);
                lck_mtx_unlock(&coalitions_list_lock);
                return COALITION_NULL;
        }

        if (coal->ref_count == 0) {
                panic("resurrecting coalition %p id:%llu type:%s, active_count:%u\n",
                                coal, coal->id, coal_type_str(coal->type), coal->active_count);
        }

        coal->ref_count++;
        coal->active_count++;

#if COALITION_DEBUG
        uint32_t rc = coal->ref_count;
        uint32_t ac = coal->active_count;
#endif

        coalition_unlock(coal);
        lck_mtx_unlock(&coalitions_list_lock);

        coal_dbg("id:%llu type:%s ref_count:%u, active_count:%u",
                 coal->id, coal_type_str(coal->type), rc, ac);

        return coal;
}

uint64_t
coalition_id(coalition_t coal)
{
        return coal->id;
}

void
task_coalition_ids(task_t task, uint64_t ids[COALITION_NUM_TYPES])
{
        int i;
        for (i = 0; i < COALITION_NUM_TYPES; i++) {
                if (task->coalition[i])
                        ids[i] = task->coalition[i]->id;
                else
                        ids[i] = 0;
        }
}

void
task_coalition_roles(task_t task, int roles[COALITION_NUM_TYPES])
{
        int i;
        memset(roles, 0, COALITION_NUM_TYPES * sizeof(roles[0]));

        for (i = 0; i < COALITION_NUM_TYPES; i++) {
                if (task->coalition[i]) {
                        coalition_lock(task->coalition[i]);
                        roles[i] = coal_call(task->coalition[i],
                                             get_taskrole, task);
                        coalition_unlock(task->coalition[i]);
                } else {
                        roles[i] = -1;
                }
        }
}


int
coalition_type(coalition_t coal)
{
        return coal->type;
}

boolean_t
coalition_is_privileged(coalition_t coal)
{
        return coal->privileged || unrestrict_coalition_syscalls;
}

boolean_t
task_is_in_privileged_coalition(task_t task, int type)
{
        if (type < 0 || type > COALITION_TYPE_MAX)
                return FALSE;
        if (unrestrict_coalition_syscalls)
                return TRUE;
        if (!task->coalition[type])
                return FALSE;
        return task->coalition[type]->privileged;
}

void task_coalition_update_gpu_stats(task_t task, uint64_t gpu_ns_delta)
{
        coalition_t coal;

        assert(task != TASK_NULL);
        if (gpu_ns_delta == 0)
                return;

        coal = task->coalition[COALITION_TYPE_RESOURCE];
        assert(coal != COALITION_NULL);

        coalition_lock(coal);
        coal->r.gpu_time += gpu_ns_delta;
        coalition_unlock(coal);
}

uint32_t task_coalition_adjust_focal_count(task_t task, int count)
{
        coalition_t coal;
        uint32_t ret;

        /*
         * For now: only use the resource coalition. Perhaps in the
         * future we may combine all coalition types, or even make
         * a special coalition type just for this.
         */
        coal = task->coalition[COALITION_TYPE_RESOURCE];
        assert(coal != COALITION_NULL);

        ret = hw_atomic_add(&coal->focal_task_count, count);

        /* catch underflow */
        assert(ret != UINT32_MAX);
        return ret;
}

uint32_t task_coalition_focal_count(task_t task)
{
        coalition_t coal;
        coal = task->coalition[COALITION_TYPE_RESOURCE];
        assert(coal != COALITION_NULL);

        return coal->focal_task_count;
}

uint32_t task_coalition_adjust_nonfocal_count(task_t task, int count)
{
        coalition_t coal;
        uint32_t ret;

        /*
         * For now: only use the resource coalition. Perhaps in the
         * future we may combine all coalition types, or even make
         * a special coalition type just for this.
         */
        coal = task->coalition[COALITION_TYPE_RESOURCE];
        assert(coal != COALITION_NULL);

        ret = hw_atomic_add(&coal->nonfocal_task_count, count);

        /* catch underflow */
        assert(ret != UINT32_MAX);
        return ret;
}

uint32_t task_coalition_nonfocal_count(task_t task)
{
        coalition_t coal;
        coal = task->coalition[COALITION_TYPE_RESOURCE];
        assert(coal != COALITION_NULL);

        return coal->nonfocal_task_count;
}

void coalition_for_each_task(coalition_t coal, void *ctx,
                             void (*callback)(coalition_t, void *, task_t))
{
        assert(coal != COALITION_NULL);

        coal_dbg("iterating tasks in coalition %p id:%llu type:%s, active_count:%u",
                 coal, coal->id, coal_type_str(coal->type), coal->active_count);

        coalition_lock(coal);

        coal_call(coal, iterate_tasks, ctx, callback);

        coalition_unlock(coal);
}


void
coalition_remove_active(coalition_t coal)
{
        coalition_lock(coal);

        assert(!coal->reaped);
        assert(coal->active_count > 0);

        coal->active_count--;

        boolean_t do_notify = FALSE;
        uint64_t notify_id = 0;
        uint32_t notify_flags = 0;
        if (coal->termrequested && coal->active_count == 0) {
                /* We only notify once, when active_count reaches zero.
                 * We just decremented, so if it reached zero, we mustn't have
                 * notified already.
                 */
                assert(!coal->terminated);
                coal->terminated = TRUE;

                assert(!coal->notified);

                coal->notified = TRUE;
#if defined(DEVELOPMENT) || defined(DEBUG)
                do_notify = coal->should_notify;
#else
                do_notify = TRUE;
#endif
                notify_id = coal->id;
                notify_flags = 0;
        }

#if COALITION_DEBUG
        uint64_t cid = coal->id;
        uint32_t rc = coal->ref_count;
        int      ac = coal->active_count;
        int      ct = coal->type;
#endif
        coalition_unlock(coal);

        coal_dbg("id:%llu type:%s ref_count:%u, active_count:%u,%s",
                 cid, coal_type_str(ct), rc, ac, do_notify ? " NOTIFY" : " ");

        if (do_notify) {
                coalition_notify_user(notify_id, notify_flags);
        }
}

/* Used for kernel_task, launchd, launchd's early boot tasks... */
kern_return_t
coalitions_adopt_init_task(task_t task)
{
        kern_return_t kr;
        kr = coalitions_adopt_task(init_coalition, task);
        if (kr != KERN_SUCCESS) {
                panic("failed to adopt task %p into default coalition: %d", task, kr);
        }
        return kr;
}

/*
 * coalition_adopt_task_internal
 * Condition: Coalition must be referenced and unlocked. Will fail if coalition
 * is already terminated.
 */
static kern_return_t
coalition_adopt_task_internal(coalition_t coal, task_t task)
{
        kern_return_t kr;

        if (task->coalition[coal->type]) {
                return KERN_ALREADY_IN_SET;
        }

        coalition_lock(coal);

        if (coal->reaped || coal->terminated) {
                coalition_unlock(coal);
                return KERN_TERMINATED;
        }

        kr = coal_call(coal, adopt_task, task);
        if (kr != KERN_SUCCESS)
                goto out_unlock;

        coal->active_count++;

        coal->ref_count++;

        task->coalition[coal->type] = coal;

out_unlock:
#if COALITION_DEBUG
        (void)coal; /* need expression after label */
        uint64_t cid = coal->id;
        uint32_t rc = coal->ref_count;
        uint32_t ct = coal->type;
#endif
        coalition_unlock(coal);

        coal_dbg("task:%d, id:%llu type:%s ref_count:%u, kr=%d",
                 task_pid(task), cid, coal_type_str(ct), rc, kr);
        return kr;
}

static kern_return_t
coalition_remove_task_internal(task_t task, int type)
{
        kern_return_t kr;

        coalition_t coal = task->coalition[type];

        if (!coal)
                return KERN_SUCCESS;

        assert(coal->type == (uint32_t)type);

        coalition_lock(coal);

        kr = coal_call(coal, remove_task, task);

#if COALITION_DEBUG
        uint64_t cid = coal->id;
        uint32_t rc = coal->ref_count;
        int      ac = coal->active_count;
        int      ct = coal->type;
#endif
        coalition_unlock(coal);

        coal_dbg("id:%llu type:%s ref_count:%u, active_count:%u, kr=%d",
                 cid, coal_type_str(ct), rc, ac, kr);

        coalition_remove_active(coal);

        return kr;
}

/*
 * coalitions_adopt_task
 * Condition: All coalitions must be referenced and unlocked.
 * Will fail if any coalition is already terminated.
 */
kern_return_t
coalitions_adopt_task(coalition_t *coals, task_t task)
{
        int i;
        kern_return_t kr;

        if (!coals || coals[COALITION_TYPE_RESOURCE] == COALITION_NULL)
                return KERN_INVALID_ARGUMENT;

        /* verify that the incoming coalitions are what they say they are */
        for (i = 0; i < COALITION_NUM_TYPES; i++)
                if (coals[i] && coals[i]->type != (uint32_t)i)
                        return KERN_INVALID_ARGUMENT;

        for (i = 0; i < COALITION_NUM_TYPES; i++) {
                kr = KERN_SUCCESS;
                if (coals[i])
                        kr = coalition_adopt_task_internal(coals[i], task);
                if (kr != KERN_SUCCESS) {
                        /* dis-associate any coalitions that just adopted this task */
                        while (--i >= 0) {
                                if (task->coalition[i])
                                        coalition_remove_task_internal(task, i);
                        }
                        break;
                }
        }
        return kr;
}

/*
 * coalitions_remove_task
 * Condition: task must be referenced and UNLOCKED; all task's coalitions must be UNLOCKED
 */
kern_return_t
coalitions_remove_task(task_t task)
{
        kern_return_t kr;
        int i;

        for (i = 0; i < COALITION_NUM_TYPES; i++) {
                kr = coalition_remove_task_internal(task, i);
                assert(kr == KERN_SUCCESS);
        }

        return kr;
}

/*
 * task_release_coalitions
 * helper function to release references to all coalitions in which
 * 'task' is a member.
 */
void
task_release_coalitions(task_t task)
{
        int i;
        for (i = 0; i < COALITION_NUM_TYPES; i++) {
                if (task->coalition[i])
                        coalition_release(task->coalition[i]);
        }
}

/*
 * coalitions_set_roles
 * for each type of coalition, if the task is a member of a coalition of
 * that type (given in the coalitions parameter) then set the role of
 * the task within that that coalition.
 */
kern_return_t coalitions_set_roles(coalition_t coalitions[COALITION_NUM_TYPES],
                                   task_t task, int roles[COALITION_NUM_TYPES])
{
        kern_return_t kr = KERN_SUCCESS;
        int i;

        for (i = 0; i < COALITION_NUM_TYPES; i++) {
                if (!coalitions[i])
                        continue;
                coalition_lock(coalitions[i]);
                kr = coal_call(coalitions[i], set_taskrole, task, roles[i]);
                coalition_unlock(coalitions[i]);
                assert(kr == KERN_SUCCESS);
        }

        return kr;
}

/*
 * coalition_terminate_internal
 * Condition: Coalition must be referenced and UNLOCKED.
 */
kern_return_t
coalition_request_terminate_internal(coalition_t coal)
{
        assert(coal->type >= 0 && coal->type <= COALITION_TYPE_MAX);

        if (coal == init_coalition[coal->type]) {
                return KERN_DEFAULT_SET;
        }

        coalition_lock(coal);

        if (coal->reaped) {
                coalition_unlock(coal);
                return KERN_INVALID_NAME;
        }

        if (coal->terminated || coal->termrequested) {
                coalition_unlock(coal);
                return KERN_TERMINATED;
        }

        coal->termrequested = TRUE;

        boolean_t do_notify = FALSE;
        uint64_t note_id = 0;
        uint32_t note_flags = 0;

        if (coal->active_count == 0) {
                /*
                 * We only notify once, when active_count reaches zero.
                 * We just set termrequested to zero. If the active count
                 * was already at zero (tasks died before we could request
                 * a termination notification), we should notify.
                 */
                assert(!coal->terminated);
                coal->terminated = TRUE;

                assert(!coal->notified);

                coal->notified = TRUE;
#if defined(DEVELOPMENT) || defined(DEBUG)
                do_notify = coal->should_notify;
#else
                do_notify = TRUE;
#endif
                note_id = coal->id;
                note_flags = 0;
        }

        coalition_unlock(coal);

        if (do_notify) {
                coalition_notify_user(note_id, note_flags);
        }

        return KERN_SUCCESS;
}

/*
 * coalition_reap_internal
 * Condition: Coalition must be referenced and UNLOCKED.
 */
kern_return_t
coalition_reap_internal(coalition_t coal)
{
        assert(coal->type <= COALITION_TYPE_MAX);

        if (coal == init_coalition[coal->type]) {
                return KERN_DEFAULT_SET;
        }

        coalition_lock(coal);
        if (coal->reaped) {
                coalition_unlock(coal);
                return KERN_TERMINATED;
        }
        if (!coal->terminated) {
                coalition_unlock(coal);
                return KERN_FAILURE;
        }
        assert(coal->termrequested);
        if (coal->active_count > 0) {
                coalition_unlock(coal);
                return KERN_FAILURE;
        }

        coal->reaped = TRUE;

        /* Caller, launchd, and coalitions list should each have a reference */
        assert(coal->ref_count > 2);

        coalition_unlock(coal);

        lck_mtx_lock(&coalitions_list_lock);
        coalition_count--;
        remqueue(&coal->coalitions);
        lck_mtx_unlock(&coalitions_list_lock);

        /* Release the list's reference and launchd's reference. */
        coalition_release(coal);
        coalition_release(coal);

        return KERN_SUCCESS;
}

#if defined(DEVELOPMENT) || defined(DEBUG)
int coalition_should_notify(coalition_t coal)
{
        int should;
        if (!coal)
                return -1;
        coalition_lock(coal);
        should = coal->should_notify;
        coalition_unlock(coal);

        return should;
}

void coalition_set_notify(coalition_t coal, int notify)
{
        if (!coal)
                return;
        coalition_lock(coal);
        coal->should_notify = !!notify;
        coalition_unlock(coal);
}
#endif

void
coalitions_init(void)
{
        kern_return_t kr;
        int i;
        const struct coalition_type *ctype;

        coalition_zone = zinit(
                        sizeof(struct coalition),
                        CONFIG_COALITION_MAX * sizeof(struct coalition),
                        COALITION_CHUNK * sizeof(struct coalition),
                        "coalitions");
        zone_change(coalition_zone, Z_NOENCRYPT, TRUE);
        queue_head_init(coalitions_q);

        if (!PE_parse_boot_argn("unrestrict_coalition_syscalls", &unrestrict_coalition_syscalls,
                sizeof (unrestrict_coalition_syscalls))) {
                unrestrict_coalition_syscalls = 0;
        }

        lck_grp_attr_setdefault(&coalitions_lck_grp_attr);
        lck_grp_init(&coalitions_lck_grp, "coalition", &coalitions_lck_grp_attr);
        lck_attr_setdefault(&coalitions_lck_attr);
        lck_mtx_init(&coalitions_list_lock, &coalitions_lck_grp, &coalitions_lck_attr);

        init_task_ledgers();

        for (i = 0, ctype = &s_coalition_types[0]; i < COALITION_NUM_TYPES; ctype++, i++) {
                /* verify the entry in the global coalition types array */
                if (ctype->type != i ||
                    !ctype->init ||
                    !ctype->dealloc ||
                    !ctype->adopt_task ||
                    !ctype->remove_task) {
                        panic("%s: Malformed coalition type %s(%d) in slot for type:%s(%d)",
                              __func__, coal_type_str(ctype->type), ctype->type, coal_type_str(i), i);
                }
                if (!ctype->has_default)
                        continue;
                kr = coalition_create_internal(ctype->type, TRUE, &init_coalition[ctype->type]);
                if (kr != KERN_SUCCESS)
                        panic("%s: could not create init %s coalition: kr:%d",
                              __func__, coal_type_str(i), kr);
        }

        /* "Leak" our reference to the global object */
}

/*
 * BSD Kernel interface functions
 *
 */
static void coalition_fill_procinfo(struct coalition *coal,
                                    struct procinfo_coalinfo *coalinfo)
{
        coalinfo->coalition_id = coal->id;
        coalinfo->coalition_type = coal->type;
        coalinfo->coalition_tasks = coalition_get_task_count(coal);
}


int coalitions_get_list(int type, struct procinfo_coalinfo *coal_list, int list_sz)
{
        int ncoals = 0;
        struct coalition *coal;

        lck_mtx_lock(&coalitions_list_lock);
        qe_foreach_element(coal, &coalitions_q, coalitions) {
                if (!coal->reaped && (type < 0 || type == (int)coal->type)) {
                        if (coal_list && ncoals < list_sz)
                                coalition_fill_procinfo(coal, &coal_list[ncoals]);
                        ++ncoals;
                }
        }
        lck_mtx_unlock(&coalitions_list_lock);

        return ncoals;
}

/*
 * Jetsam coalition interface
 *
 */
boolean_t coalition_is_leader(task_t task, int coal_type, coalition_t *coal)
{
        coalition_t c;
        boolean_t ret;

        if (coal) /* handle the error cases gracefully */
                *coal = COALITION_NULL;

        if (!task)
                return FALSE;

        if (coal_type > COALITION_TYPE_MAX)
                return FALSE;

        c = task->coalition[coal_type];
        if (!c)
                return FALSE;

        assert((int)c->type == coal_type);

        coalition_lock(c);

        if (coal)
                *coal = c;

        ret = FALSE;
        if (c->type == COALITION_TYPE_JETSAM && c->j.leader == task)
                ret = TRUE;

        coalition_unlock(c);

        return ret;
}


task_t coalition_get_leader(coalition_t coal)
{
        task_t leader = TASK_NULL;

        if (!coal)
                return TASK_NULL;

        coalition_lock(coal);
        if (coal->type != COALITION_TYPE_JETSAM)
                goto out_unlock;

        leader = coal->j.leader;
        if (leader != TASK_NULL)
                task_reference(leader);

out_unlock:
        coalition_unlock(coal);
        return leader;
}


int coalition_get_task_count(coalition_t coal)
{
        int ntasks = 0;
        struct queue_entry *qe;
        if (!coal)
                return 0;

        coalition_lock(coal);
        switch (coal->type) {
        case COALITION_TYPE_RESOURCE:
                qe_foreach(qe, &coal->r.tasks)
                        ntasks++;
                break;
        case COALITION_TYPE_JETSAM:
                if (coal->j.leader)
                        ntasks++;
                qe_foreach(qe, &coal->j.other)
                        ntasks++;
                qe_foreach(qe, &coal->j.extensions)
                        ntasks++;
                qe_foreach(qe, &coal->j.services)
                        ntasks++;
                break;
        default:
                break;
        }
        coalition_unlock(coal);

        return ntasks;
}


static uint64_t i_get_list_footprint(queue_t list, int type, int *ntasks)
{
        task_t task;
        uint64_t bytes = 0;

        qe_foreach_element(task, list, task_coalition[type]) {
                bytes += get_task_phys_footprint(task);
                coal_dbg("    [%d] task_pid:%d, type:%d, footprint:%lld",
                         *ntasks, task_pid(task), type, bytes);
                *ntasks += 1;
        }

        return bytes;
}

uint64_t coalition_get_page_count(coalition_t coal, int *ntasks)
{
        uint64_t bytes = 0;
        int num_tasks = 0;

        if (ntasks)
                *ntasks = 0;
        if (!coal)
                return bytes;

        coalition_lock(coal);

        switch (coal->type) {
        case COALITION_TYPE_RESOURCE:
                bytes += i_get_list_footprint(&coal->r.tasks, COALITION_TYPE_RESOURCE, &num_tasks);
                break;
        case COALITION_TYPE_JETSAM:
                if (coal->j.leader) {
                        bytes += get_task_phys_footprint(coal->j.leader);
                        num_tasks = 1;
                }
                bytes += i_get_list_footprint(&coal->j.extensions, COALITION_TYPE_JETSAM, &num_tasks);
                bytes += i_get_list_footprint(&coal->j.services, COALITION_TYPE_JETSAM, &num_tasks);
                bytes += i_get_list_footprint(&coal->j.other, COALITION_TYPE_JETSAM, &num_tasks);
                break;
        default:
                break;
        }

        coalition_unlock(coal);

        if (ntasks)
                *ntasks = num_tasks;

        return bytes / PAGE_SIZE_64;
}

struct coal_sort_s {
        int pid;
        int usr_order;
        uint64_t bytes;
};

/*
 * return < 0 for a < b
 *          0 for a == b
 *        > 0 for a > b
 */
typedef int (*cmpfunc_t)(const void *a, const void *b);

extern void
qsort(void *a, size_t n, size_t es, cmpfunc_t cmp);

static int dflt_cmp(const void *a, const void *b)
{
        const struct coal_sort_s *csA = (const struct coal_sort_s *)a;
        const struct coal_sort_s *csB = (const struct coal_sort_s *)b;

        /*
         * if both A and B are equal, use a memory descending sort
         */
        if (csA->usr_order == csB->usr_order)
                return (int)((int64_t)csB->bytes - (int64_t)csA->bytes);

        /* otherwise, return the relationship between user specified orders */
        return (csA->usr_order - csB->usr_order);
}

static int mem_asc_cmp(const void *a, const void *b)
{
        const struct coal_sort_s *csA = (const struct coal_sort_s *)a;
        const struct coal_sort_s *csB = (const struct coal_sort_s *)b;

        return (int)((int64_t)csA->bytes - (int64_t)csB->bytes);
}

static int mem_dec_cmp(const void *a, const void *b)
{
        const struct coal_sort_s *csA = (const struct coal_sort_s *)a;
        const struct coal_sort_s *csB = (const struct coal_sort_s *)b;

        return (int)((int64_t)csB->bytes - (int64_t)csA->bytes);
}

static int usr_asc_cmp(const void *a, const void *b)
{
        const struct coal_sort_s *csA = (const struct coal_sort_s *)a;
        const struct coal_sort_s *csB = (const struct coal_sort_s *)b;

        return (csA->usr_order - csB->usr_order);
}

static int usr_dec_cmp(const void *a, const void *b)
{
        const struct coal_sort_s *csA = (const struct coal_sort_s *)a;
        const struct coal_sort_s *csB = (const struct coal_sort_s *)b;

        return (csB->usr_order - csA->usr_order);
}

/* avoid dynamic allocation in this path */
#define MAX_SORTED_PIDS  80

static int coalition_get_sort_list(coalition_t coal, int sort_order, queue_t list,
                                   struct coal_sort_s *sort_array, int array_sz)
{
        int ntasks = 0;
        task_t task;

        assert(sort_array != NULL);

        if (array_sz <= 0)
                return 0;

        if (!list) {
                /*
                 * this function will only be called with a NULL
                 * list for JETSAM-type coalitions, and is intended
                 * to investigate the leader process
                 */
                if (coal->type != COALITION_TYPE_JETSAM ||
                    coal->j.leader == TASK_NULL)
                        return 0;
                sort_array[0].pid = task_pid(coal->j.leader);
                switch (sort_order) {
                case COALITION_SORT_DEFAULT:
                        sort_array[0].usr_order = 0;
                        /* fall-through */
                case COALITION_SORT_MEM_ASC:
                case COALITION_SORT_MEM_DEC:
                        sort_array[0].bytes = get_task_phys_footprint(coal->j.leader);
                        break;
                case COALITION_SORT_USER_ASC:
                case COALITION_SORT_USER_DEC:
                        sort_array[0].usr_order = 0;
                        break;
                default:
                        break;
                }
                return 1;
        }

        qe_foreach_element(task, list, task_coalition[coal->type]) {
                if (ntasks >= array_sz) {
                        printf("WARNING: more than %d pids in coalition %llu\n",
                               MAX_SORTED_PIDS, coal->id);
                        break;
                }

                sort_array[ntasks].pid = task_pid(task);

                switch (sort_order) {
                case COALITION_SORT_DEFAULT:
                        sort_array[ntasks].usr_order = 0;
                        /* fall-through */
                case COALITION_SORT_MEM_ASC:
                case COALITION_SORT_MEM_DEC:
                        sort_array[ntasks].bytes = get_task_phys_footprint(task);
                        break;
                case COALITION_SORT_USER_ASC:
                case COALITION_SORT_USER_DEC:
                        sort_array[ntasks].usr_order = 0;
                        break;
                default:
                        break;
                }

                ntasks++;
        }

        return ntasks;
}

int coalition_get_pid_list(coalition_t coal, uint32_t rolemask, int sort_order,
                           int *pid_list, int list_sz)
{
        struct i_jetsam_coalition *cj;
        int ntasks = 0;
        cmpfunc_t cmp_func = NULL;
        struct coal_sort_s sort_array[MAX_SORTED_PIDS] = { {0,0,0} }; /* keep to < 2k */

        if (!coal ||
            !(rolemask & COALITION_ROLEMASK_ALLROLES) ||
            !pid_list || list_sz < 1) {
                coal_dbg("Invalid parameters: coal:%p, type:%d, rolemask:0x%x, "
                         "pid_list:%p, list_sz:%d", coal, coal ? coal->type : -1,
                         rolemask, pid_list, list_sz);
                return -EINVAL;
        }

        switch (sort_order) {
        case COALITION_SORT_NOSORT:
                cmp_func = NULL;
                break;
        case COALITION_SORT_DEFAULT:
                cmp_func = dflt_cmp;
                break;
        case COALITION_SORT_MEM_ASC:
                cmp_func = mem_asc_cmp;
                break;
        case COALITION_SORT_MEM_DEC:
                cmp_func = mem_dec_cmp;
                break;
        case COALITION_SORT_USER_ASC:
                cmp_func = usr_asc_cmp;
                break;
        case COALITION_SORT_USER_DEC:
                cmp_func = usr_dec_cmp;
                break;
        default:
                return -ENOTSUP;
        }

        coalition_lock(coal);

        if (coal->type == COALITION_TYPE_RESOURCE) {
                ntasks += coalition_get_sort_list(coal, sort_order, &coal->r.tasks,
                                                  sort_array, MAX_SORTED_PIDS);
                goto unlock_coal;
        }

        cj = &coal->j;

        if (rolemask & COALITION_ROLEMASK_UNDEF)
                ntasks += coalition_get_sort_list(coal, sort_order, &cj->other,
                                                  sort_array + ntasks,
                                                  MAX_SORTED_PIDS - ntasks);

        if (rolemask & COALITION_ROLEMASK_XPC)
                ntasks += coalition_get_sort_list(coal, sort_order, &cj->services,
                                                  sort_array + ntasks,
                                                  MAX_SORTED_PIDS - ntasks);

        if (rolemask & COALITION_ROLEMASK_EXT)
                ntasks += coalition_get_sort_list(coal, sort_order, &cj->extensions,
                                                  sort_array + ntasks,
                                                  MAX_SORTED_PIDS - ntasks);

        if (rolemask & COALITION_ROLEMASK_LEADER)
                ntasks += coalition_get_sort_list(coal, sort_order, NULL,
                                                  sort_array + ntasks,
                                                  MAX_SORTED_PIDS - ntasks);

unlock_coal:
        coalition_unlock(coal);

        /* sort based on the chosen criterion (no sense sorting 1 item) */
        if (cmp_func && ntasks > 1)
                qsort(sort_array, ntasks, sizeof(struct coal_sort_s), cmp_func);

        for (int i = 0; i < ntasks; i++) {
                if (i >= list_sz)
                        break;
                coal_dbg(" [%d] PID:%d, footprint:%lld, usr_order:%d",
                         i, sort_array[i].pid, sort_array[i].bytes,
                         sort_array[i].usr_order);
                pid_list[i] = sort_array[i].pid;
        }

        return ntasks;
}