/erts/emulator/beam/erl_bif_info.c

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/*
 * %CopyrightBegin%
 *
 * Copyright Ericsson AB 1999-2018. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * %CopyrightEnd%
 */

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#define ERTS_WANT_MEM_MAPPERS
#include "sys.h"
#include "erl_vm.h"
#include "global.h"
#include "erl_process.h"
#include "error.h"
#include "erl_driver.h"
#include "erl_nif.h"
#include "bif.h"
#include "big.h"
#include "erl_version.h"
#include "erl_compile_flags.h"
#include "erl_db_util.h"
#include "erl_message.h"
#include "erl_binary.h"
#include "erl_db.h"
#include "erl_mtrace.h"
#include "dist.h"
#include "erl_gc.h"
#include "erl_cpu_topology.h"
#include "erl_async.h"
#include "erl_thr_progress.h"
#include "erl_bif_unique.h"
#include "erl_map.h"
#include "erl_check_io.h"
#define ERTS_PTAB_WANT_DEBUG_FUNCS__
#include "erl_ptab.h"
#include "erl_time.h"
#include "erl_proc_sig_queue.h"
#include "erl_alloc_util.h"
#ifdef HIPE
#include "hipe_arch.h"
#endif

#ifdef ERTS_ENABLE_LOCK_COUNT
#include "erl_lock_count.h"
#endif

#ifdef VALGRIND
#include <valgrind/valgrind.h>
#include <valgrind/memcheck.h>
#endif

static Export* alloc_info_trap = NULL;
static Export* alloc_sizes_trap = NULL;
static Export* gather_io_bytes_trap = NULL;

static Export *gather_sched_wall_time_res_trap;
static Export *gather_msacc_res_trap;
static Export *gather_gc_info_res_trap;
static Export *gather_system_check_res_trap;

static Export *is_process_alive_trap;


#define DECL_AM(S) Eterm AM_ ## S = am_atom_put(#S, sizeof(#S) - 1)

static char otp_version[] = ERLANG_OTP_VERSION;
/* Keep erts_system_version as a global variable for easy access from a core */
static char erts_system_version[] = ("Erlang/OTP " ERLANG_OTP_RELEASE
				     "%s"
				     " [erts-" ERLANG_VERSION "]"
#ifndef OTP_RELEASE
#ifdef ERLANG_GIT_VERSION
				     " [source-" ERLANG_GIT_VERSION "]"
#else
				     " [source]"
#endif
#endif	
#ifdef ARCH_64
				     " [64-bit]"
#endif
				     " [smp:%beu:%beu]"
				     " [ds:%beu:%beu:%beu]"
#if defined(ERTS_DIRTY_SCHEDULERS_TEST)
				     " [dirty-schedulers-TEST]"
#endif
				     " [async-threads:%d]"
#ifdef HIPE
				     " [hipe]"
#endif	
#ifdef ET_DEBUG
#if ET_DEBUG
				     " [type-assertions]"
#endif
#endif	
#ifdef DEBUG
				     " [debug-compiled]"
#endif	
#ifdef ERTS_ENABLE_LOCK_CHECK
				     " [lock-checking]"
#endif
#ifdef ERTS_ENABLE_LOCK_COUNT
				     " [lock-counting]"
#endif
#ifdef ERTS_OPCODE_COUNTER_SUPPORT
				     " [instruction-counting]"
#endif
#ifdef PURIFY
				     " [purify-compiled]"
#endif	
#ifdef VALGRIND
				     " [valgrind-compiled]"
#endif
#ifdef ERTS_FRMPTR
				     " [frame-pointer]"
#endif
#ifdef USE_LTTNG
				     " [lttng]"
#endif
#ifdef USE_DTRACE
				     " [dtrace]"
#endif
#ifdef USE_SYSTEMTAP
				     " [systemtap]"
#endif
#ifdef SHCOPY
				     " [sharing-preserving]"
#endif
				     "\n");

#define ASIZE(a) (sizeof(a)/sizeof(a[0]))

#if defined(HAVE_SOLARIS_SPARC_PERFMON)
# include <sys/ioccom.h>
# define PERFMON_SETPCR			_IOW('P', 1, unsigned long long)
# define PERFMON_GETPCR			_IOR('P', 2, unsigned long long)
#endif

/* Cached, pre-built {OsType,OsFlavor} and {Major,Minor,Build} tuples */
static Eterm os_type_tuple;
static Eterm os_version_tuple;

static Eterm
current_function(Process* p, ErtsHeapFactory *hfact, Process* rp,
                 int full_info, Uint reserve_size, int flags);
static Eterm current_stacktrace(ErtsHeapFactory *hfact, Process* rp,
                                Uint reserve_size);

static Eterm
bld_bin_list(Uint **hpp, Uint *szp, ErlOffHeap* oh)
{
    struct erl_off_heap_header* ohh;
    Eterm res = NIL;
    Eterm tuple;

    for (ohh = oh->first; ohh; ohh = ohh->next) {
	if (ohh->thing_word == HEADER_PROC_BIN) {
	    ProcBin* pb = (ProcBin*) ohh;
	    Eterm val = erts_bld_uword(hpp, szp, (UWord) pb->val);
	    Eterm orig_size = erts_bld_uint(hpp, szp, pb->val->orig_size);
    
	    if (szp)
		*szp += 4+2;
	    if (hpp) {
		Uint refc = (Uint) erts_refc_read(&pb->val->intern.refc, 1);
		tuple = TUPLE3(*hpp, val, orig_size, make_small(refc));
		res = CONS(*hpp + 4, tuple, res);
		*hpp += 4+2;
	    }
	}
    }
    return res;
}

static Eterm
bld_magic_ref_bin_list(Uint **hpp, Uint *szp, ErlOffHeap* oh)
{
    struct erl_off_heap_header* ohh;
    Eterm res = NIL;
    Eterm tuple;

    for (ohh = oh->first; ohh; ohh = ohh->next) {
	if (is_ref_thing_header((*((Eterm *) ohh)))) {
            ErtsMRefThing *mrtp = (ErtsMRefThing *) ohh;
	    Eterm val = erts_bld_uword(hpp, szp, (UWord) mrtp->mb);
	    Eterm orig_size = erts_bld_uint(hpp, szp, mrtp->mb->orig_size);
    
	    if (szp)
		*szp += 4+2;
	    if (hpp) {
		Uint refc = (Uint) erts_refc_read(&mrtp->mb->intern.refc, 1);
		tuple = TUPLE3(*hpp, val, orig_size, make_small(refc));
		res = CONS(*hpp + 4, tuple, res);
		*hpp += 4+2;
	    }
	}
    }
    return res;
}


/*
  make_monitor_list:
  returns a list of records..
  -record(erl_monitor, {
            type, % process | port | time_offset | dist_process | resource
                  % | node | nodes | suspend
            dir, % origin | target
	    ref, % reference or []
	    pid, % Process or nodename
	    extra % registered name, integer or []
          }).
*/

static int do_calc_mon_size(ErtsMonitor *mon, void *vpsz, Sint reds)
{
    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
    Uint *psz = vpsz;
    *psz += is_immed(mdp->ref) ? 0 : NC_HEAP_SIZE(mdp->ref);

    if (mon->type == ERTS_MON_TYPE_RESOURCE && erts_monitor_is_target(mon))
        *psz += erts_resource_ref_size(mon->other.ptr);
    else
        *psz += is_immed(mon->other.item) ? 0 : NC_HEAP_SIZE(mon->other.item);

    *psz += 9; /* CONS + 6-tuple */
    return 1;
}

typedef struct {
    Process *p;
    Eterm *hp;
    Eterm res;
    Eterm tag;
} MonListContext;

static int do_make_one_mon_element(ErtsMonitor *mon, void * vpmlc, Sint reds)
{
    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
    MonListContext *pmlc = vpmlc;
    Eterm tup, t, d, r, p, x;

    r = is_immed(mdp->ref) ? mdp->ref : STORE_NC(&(pmlc->hp), &MSO(pmlc->p), mdp->ref);
    if (mon->type == ERTS_MON_TYPE_RESOURCE && erts_monitor_is_target(mon))
        p = erts_bld_resource_ref(&(pmlc->hp), &MSO(pmlc->p), mon->other.ptr);
    else
        p = (is_immed(mon->other.item)
             ? mon->other.item
             : STORE_NC(&(pmlc->hp), &MSO(pmlc->p), mon->other.item));

    if (mon->flags & ERTS_ML_FLG_NAME)
        x = ((ErtsMonitorDataExtended *) mdp)->u.name;
    else if (erts_monitor_is_target(mon))
        x = NIL;
    else if (mon->type == ERTS_MON_TYPE_NODE || mon->type == ERTS_MON_TYPE_NODES)
        x = make_small(((ErtsMonitorDataExtended *) mdp)->u.refc);
    else
        x = NIL;

    switch (mon->type) {
    case ERTS_MON_TYPE_PROC:
        t = am_process;
        break;
    case ERTS_MON_TYPE_PORT:
        t = am_port;
        break;
    case ERTS_MON_TYPE_TIME_OFFSET:
        t = am_time_offset;
        break;
    case ERTS_MON_TYPE_DIST_PROC: {
        ERTS_DECL_AM(dist_process);
        t = AM_dist_process;
        break;
    }
    case ERTS_MON_TYPE_RESOURCE: {
        ERTS_DECL_AM(resource);
        t = AM_resource;
        break;
    }
    case ERTS_MON_TYPE_NODE:
        t = am_node;
        break;
    case ERTS_MON_TYPE_NODES: {
        ERTS_DECL_AM(nodes);
        t = AM_nodes;
        break;
    }
    case ERTS_MON_TYPE_SUSPEND:
        t = am_suspend;
        break;
    default:
        ERTS_INTERNAL_ERROR("Unknown monitor type");
        t = am_error;
        break;
    }
    if (erts_monitor_is_target(mon)) {
        ERTS_DECL_AM(target);
        d = AM_target;
    }
    else {
        ERTS_DECL_AM(origin);
        d = AM_origin;
    }
    tup = TUPLE6(pmlc->hp, pmlc->tag, t, d, r, p, x);
    pmlc->hp += 7;
    pmlc->res = CONS(pmlc->hp, tup, pmlc->res);
    pmlc->hp += 2;
    return 1;
}

static Eterm 
make_monitor_list(Process *p, int tree, ErtsMonitor *root, Eterm tail)
{
    DECL_AM(erl_monitor);
    Uint sz = 0;
    MonListContext mlc;
    void (*foreach)(ErtsMonitor *,
                    ErtsMonitorFunc,
                    void *);

    foreach = tree ? erts_monitor_tree_foreach : erts_monitor_list_foreach;

    (*foreach)(root, do_calc_mon_size, &sz);
    if (sz == 0)
	return tail;
    mlc.p = p;
    mlc.hp = HAlloc(p,sz);
    mlc.res = tail;
    mlc.tag = AM_erl_monitor;
    (*foreach)(root, do_make_one_mon_element, &mlc);
    return mlc.res;
}

/*
  make_link_list:
  returns a list of records..
  -record(erl_link, {
            type, % process | port | dist_process
	    pid, % Process or port
            id % (address)
          }).
*/

static int calc_lnk_size(ErtsLink *lnk, void *vpsz, Sint reds)
{
    Uint *psz = vpsz;
    Uint sz = 0;
    ErtsLinkData *ldp = erts_link_to_data(lnk);

    (void) erts_bld_uword(NULL, &sz, (UWord) ldp);

    *psz += sz;
    *psz += is_immed(lnk->other.item) ? 0 : size_object(lnk->other.item);
    *psz += 7; /* CONS + 4-tuple */
    return 1;
}

typedef struct {
    Process *p;
    Eterm *hp;
    Eterm res;
    Eterm tag;
} LnkListContext;

static int make_one_lnk_element(ErtsLink *lnk, void * vpllc, Sint reds)
{
    LnkListContext *pllc = vpllc;
    Eterm tup, t, pid, id;
    ErtsLinkData *ldp = erts_link_to_data(lnk);

    id = erts_bld_uword(&pllc->hp, NULL, (UWord) ldp);

    if (is_immed(lnk->other.item))
        pid = lnk->other.item;
    else {
        Uint sz = size_object(lnk->other.item);
        pid = copy_struct(lnk->other.item, sz, &(pllc->hp), &MSO(pllc->p));
    }

    switch (lnk->type) {
    case ERTS_LNK_TYPE_PROC:
        t = am_process;
        break;
    case ERTS_LNK_TYPE_PORT:
        t = am_port;
        break;
    case ERTS_LNK_TYPE_DIST_PROC: {
        ERTS_DECL_AM(dist_process);
        t = AM_dist_process;
        break;
    }
    default:
        ERTS_INTERNAL_ERROR("Unkown link type");
        t = am_undefined;
        break;
    }

    tup = TUPLE4(pllc->hp, pllc->tag, t, pid, id);
    pllc->hp += 5;
    pllc->res = CONS(pllc->hp, tup, pllc->res);
    pllc->hp += 2;
    return 1;
}

static Eterm 
make_link_list(Process *p, int tree, ErtsLink *root, Eterm tail)
{
    DECL_AM(erl_link);
    Uint sz = 0;
    LnkListContext llc;
    void (*foreach)(ErtsLink *,
                    ErtsLinkFunc,
                    void *);

    foreach = tree ? erts_link_tree_foreach : erts_link_list_foreach;

    (*foreach)(root, calc_lnk_size, (void *) &sz);
    if (sz == 0) {
	return tail;
    }
    llc.p = p;
    llc.hp = HAlloc(p,sz);
    llc.res = tail;
    llc.tag = AM_erl_link;
    (*foreach)(root, make_one_lnk_element, (void *) &llc);
    return llc.res;
}

int
erts_print_system_version(fmtfn_t to, void *arg, Process *c_p)
{
    int i, rc = -1;
    char *rc_str = "";
    char rc_buf[100];
    char *ov = otp_version;
    Uint total, online, active;
    Uint dirty_cpu, dirty_cpu_onln, dirty_io;

    erts_schedulers_state(&total, &online, &active,
			  &dirty_cpu, &dirty_cpu_onln, NULL,
			  &dirty_io, NULL);
    for (i = 0; i < sizeof(otp_version)-4; i++) {
	if (ov[i] == '-' && ov[i+1] == 'r' && ov[i+2] == 'c')
	    rc = atoi(&ov[i+3]);
    }
    if (rc >= 0) {
	if (rc == 0)
	    rc_str = " [DEVELOPMENT]";
	else {
	    erts_snprintf(rc_buf, sizeof(rc_buf), " [RELEASE CANDIDATE %d]", rc);
	    rc_str = rc_buf;
	}
    }
    return erts_print(to, arg, erts_system_version,
		      rc_str
		      , total, online
		      , dirty_cpu, dirty_cpu_onln, dirty_io
		      , erts_async_max_threads
	);
}

typedef struct {
    /* {Entity,Node} = {monitor.Name,monitor.Pid} for external by name
     * {Entity,Node} = {monitor.Pid,NIL} for external/external by pid
     * {Entity,Node} = {monitor.Name,erlang:node()} for internal by name 
     * {Entity,Node} = {monitor.resource,MON_NIF_TARGET}*/
    union {
	Eterm term;
	ErtsResource* resource;
    }entity;
    int named;
    Uint16 type;
    Eterm node;
    /* pid is actual target being monitored, no matter pid/port or name */
    Eterm pid;
} MonitorInfo;

typedef struct {
    MonitorInfo *mi;
    Uint mi_i;
    Uint mi_max;
    int sz;
} MonitorInfoCollection;

#define INIT_MONITOR_INFOS(MIC) do {		\
    (MIC).mi = NULL;				\
    (MIC).mi_i = (MIC).mi_max = 0;		\
    (MIC).sz = 0;                               \
} while(0)

#define MI_INC 50
#define EXTEND_MONITOR_INFOS(MICP)					\
do {									\
    if ((MICP)->mi_i >= (MICP)->mi_max) {				\
	(MICP)->mi = ((MICP)->mi ? erts_realloc(ERTS_ALC_T_TMP,		\
						(MICP)->mi,		\
						((MICP)->mi_max+MI_INC)	\
						* sizeof(MonitorInfo))	\
		      : erts_alloc(ERTS_ALC_T_TMP,			\
				   MI_INC*sizeof(MonitorInfo)));	\
	(MICP)->mi_max += MI_INC;					\
    }									\
 } while (0)
#define DESTROY_MONITOR_INFOS(MIC)			\
do {							\
    if ((MIC).mi != NULL) {				\
	erts_free(ERTS_ALC_T_TMP, (void *) (MIC).mi);	\
    }							\
 } while (0)

static int collect_one_link(ErtsLink *lnk, void *vmicp, Sint reds)
{
    MonitorInfoCollection *micp = vmicp;
    EXTEND_MONITOR_INFOS(micp);
    micp->mi[micp->mi_i].entity.term = lnk->other.item;
    micp->sz += 2 + NC_HEAP_SIZE(lnk->other.item);
    micp->mi_i++;
    return 1;
} 

static int collect_one_origin_monitor(ErtsMonitor *mon, void *vmicp, Sint reds)
{
    if (erts_monitor_is_origin(mon)) {
        MonitorInfoCollection *micp = vmicp;
 
        EXTEND_MONITOR_INFOS(micp);

        micp->mi[micp->mi_i].type = mon->type;

        switch (mon->type) {
        case ERTS_MON_TYPE_PROC:
        case ERTS_MON_TYPE_PORT:
        case ERTS_MON_TYPE_DIST_PROC:
        case ERTS_MON_TYPE_TIME_OFFSET:
            if (!(mon->flags & ERTS_ML_FLG_NAME)) {
                micp->mi[micp->mi_i].named = 0;
                micp->mi[micp->mi_i].entity.term = mon->other.item;
                micp->mi[micp->mi_i].node = NIL;
                if (is_not_atom(mon->other.item))
                    micp->sz += NC_HEAP_SIZE(mon->other.item);
            }
            else {
                ErtsMonitorDataExtended *mdep;
                micp->mi[micp->mi_i].named = !0;
                mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(mon);
                micp->mi[micp->mi_i].entity.term = mdep->u.name;
                if (mdep->dist)
                    micp->mi[micp->mi_i].node = mdep->dist->nodename;
                else
                    micp->mi[micp->mi_i].node = erts_this_dist_entry->sysname;
                micp->sz += 3; /* need one 2-tuple */
            }

            /* have always pid at hand, to assist with figuring out if its a port or
             * a process, when we monitored by name and process_info is requested.
             * See: erl_bif_info.c:process_info_aux section for am_monitors */
            micp->mi[micp->mi_i].pid = mon->other.item;

            micp->mi_i++;
            micp->sz += 2 + 3; /* For a cons cell and a 2-tuple */
            break;
        default:
            break;
        }
    }
    return 1;
}

static int collect_one_target_monitor(ErtsMonitor *mon, void *vmicp, Sint reds)
{
    MonitorInfoCollection *micp = vmicp;
 
    if (erts_monitor_is_target(mon)) {

        EXTEND_MONITOR_INFOS(micp);
  
        micp->mi[micp->mi_i].type = mon->type;
        micp->mi[micp->mi_i].named = !!(mon->flags & ERTS_ML_FLG_NAME);
        switch (mon->type) {

        case ERTS_MON_TYPE_PROC:
        case ERTS_MON_TYPE_PORT:
        case ERTS_MON_TYPE_DIST_PROC:

            micp->mi[micp->mi_i].entity.term = mon->other.item;
            micp->mi[micp->mi_i].node = NIL;
            micp->sz += NC_HEAP_SIZE(mon->other.item);

            micp->sz += 2; /* cons */;
            micp->mi_i++;
            break;

        case ERTS_MON_TYPE_RESOURCE:

            micp->mi[micp->mi_i].entity.resource = mon->other.ptr;
            micp->mi[micp->mi_i].node = NIL;
            micp->sz += erts_resource_ref_size(mon->other.ptr);

            micp->sz += 2; /* cons */;
            micp->mi_i++;
            break;

        default:
            break;
        }
    }
    return 1;
}

typedef struct {
    ErtsMonitorSuspend **smi;
    Uint smi_i;
    Uint smi_max;
    Uint sz;
} ErtsSuspendMonitorInfoCollection;

#define ERTS_INIT_SUSPEND_MONITOR_INFOS(SMIC) do {		        \
    (SMIC).smi = NULL;							\
    (SMIC).smi_i = (SMIC).smi_max = 0;					\
    (SMIC).sz = 0;                               			\
} while(0)

#define ERTS_SMI_INC 50
#define ERTS_EXTEND_SUSPEND_MONITOR_INFOS(SMICP)			\
do {									\
    if ((SMICP)->smi_i >= (SMICP)->smi_max) {				\
	(SMICP)->smi = ((SMICP)->smi					\
			? erts_realloc(ERTS_ALC_T_TMP,			\
				       (SMICP)->smi,			\
				       ((SMICP)->smi_max		\
					+ ERTS_SMI_INC)			\
				       * sizeof(ErtsMonitorSuspend *))	\
			: erts_alloc(ERTS_ALC_T_TMP,			\
				     ERTS_SMI_INC			\
				     * sizeof(ErtsMonitorSuspend *)));	\
	(SMICP)->smi_max += ERTS_SMI_INC;				\
    }									\
 } while (0)

#define ERTS_DESTROY_SUSPEND_MONITOR_INFOS(SMIC)			\
do {									\
    if ((SMIC).smi != NULL) {						\
	erts_free(ERTS_ALC_T_TMP, (void *) (SMIC).smi);			\
    }									\
 } while (0)

static int
collect_one_suspend_monitor(ErtsMonitor *mon, void *vsmicp, Sint reds)
{
    if (mon->type == ERTS_MON_TYPE_SUSPEND) {
        Sint count;
        erts_aint_t mstate;
        ErtsMonitorSuspend *msp;
        ErtsSuspendMonitorInfoCollection *smicp;

        msp = (ErtsMonitorSuspend *) erts_monitor_to_data(mon);
        smicp = vsmicp;

	ERTS_EXTEND_SUSPEND_MONITOR_INFOS(smicp);

	smicp->smi[smicp->smi_i] = msp;
	smicp->sz += 2 /* cons */ + 4 /* 3-tuple */;

        mstate = erts_atomic_read_nob(&msp->state);

        count = (Sint) (mstate & ERTS_MSUSPEND_STATE_COUNTER_MASK);
	if (!IS_SSMALL(count))
	    smicp->sz += BIG_UINT_HEAP_SIZE;

	smicp->smi_i++;
    }
    return 1;
}

/*
 * process_info/[1,2]
 */

/*
 * All valid process_info arguments.
 */

#define ERTS_PI_IX_REGISTERED_NAME                      0
#define ERTS_PI_IX_CURRENT_FUNCTION                     1
#define ERTS_PI_IX_INITIAL_CALL                         2
#define ERTS_PI_IX_STATUS                               3
#define ERTS_PI_IX_MESSAGES                             4
#define ERTS_PI_IX_MESSAGE_QUEUE_LEN                    5
#define ERTS_PI_IX_LINKS                                6
#define ERTS_PI_IX_MONITORS                             7
#define ERTS_PI_IX_MONITORED_BY                         8
#define ERTS_PI_IX_DICTIONARY                           9
#define ERTS_PI_IX_TRAP_EXIT                            10
#define ERTS_PI_IX_ERROR_HANDLER                        11
#define ERTS_PI_IX_HEAP_SIZE                            12
#define ERTS_PI_IX_STACK_SIZE                           13
#define ERTS_PI_IX_MEMORY                               14
#define ERTS_PI_IX_GARBAGE_COLLECTION                   15
#define ERTS_PI_IX_GROUP_LEADER                         16
#define ERTS_PI_IX_REDUCTIONS                           17
#define ERTS_PI_IX_PRIORITY                             18
#define ERTS_PI_IX_TRACE                                19
#define ERTS_PI_IX_BINARY                               20
#define ERTS_PI_IX_SEQUENTIAL_TRACE_TOKEN               21
#define ERTS_PI_IX_CATCHLEVEL                           22
#define ERTS_PI_IX_BACKTRACE                            23
#define ERTS_PI_IX_LAST_CALLS                           24
#define ERTS_PI_IX_TOTAL_HEAP_SIZE                      25
#define ERTS_PI_IX_SUSPENDING                           26
#define ERTS_PI_IX_MIN_HEAP_SIZE                        27
#define ERTS_PI_IX_MIN_BIN_VHEAP_SIZE                   28
#define ERTS_PI_IX_MAX_HEAP_SIZE                        29
#define ERTS_PI_IX_CURRENT_LOCATION                     30
#define ERTS_PI_IX_CURRENT_STACKTRACE                   31
#define ERTS_PI_IX_MESSAGE_QUEUE_DATA                   32
#define ERTS_PI_IX_GARBAGE_COLLECTION_INFO              33
#define ERTS_PI_IX_MAGIC_REF                            34
#define ERTS_PI_IX_FULLSWEEP_AFTER                      35

#define ERTS_PI_FLAG_SINGELTON                          (1 << 0)
#define ERTS_PI_FLAG_ALWAYS_WRAP                        (1 << 1)
#define ERTS_PI_FLAG_WANT_MSGS                          (1 << 2)
#define ERTS_PI_FLAG_NEED_MSGQ_LEN                      (1 << 3)
#define ERTS_PI_FLAG_FORCE_SIG_SEND                     (1 << 4)
#define ERTS_PI_FLAG_REQUEST_FOR_OTHER                  (1 << 5)

#define ERTS_PI_UNRESERVE(RS, SZ) \
    (ASSERT((RS) >= (SZ)), (RS) -= (SZ))


typedef struct {
    Eterm name;
    Uint reserve_size;
    int flags;
    ErtsProcLocks locks;
} ErtsProcessInfoArgs;

static ErtsProcessInfoArgs pi_args[] = {
    {am_registered_name, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_current_function, 4, ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_initial_call, 4, 0, ERTS_PROC_LOCK_MAIN},
    {am_status, 0, 0, 0},
    {am_messages, 0, ERTS_PI_FLAG_WANT_MSGS|ERTS_PI_FLAG_NEED_MSGQ_LEN|ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_message_queue_len, 0, ERTS_PI_FLAG_NEED_MSGQ_LEN, ERTS_PROC_LOCK_MAIN},
    {am_links, 0, ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_monitors, 0, ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_monitored_by, 0, ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_dictionary, 0, ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_trap_exit, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_error_handler, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_heap_size, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_stack_size, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_memory, 0, ERTS_PI_FLAG_NEED_MSGQ_LEN|ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_garbage_collection, 3+2 + 3+2 + 3+2 + 3+2 + 3+2 + ERTS_MAX_HEAP_SIZE_MAP_SZ, 0, ERTS_PROC_LOCK_MAIN},
    {am_group_leader, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_reductions, 0, ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_priority, 0, 0, 0},
    {am_trace, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_binary, 0, ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_sequential_trace_token, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_catchlevel, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_backtrace, 0, ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_last_calls, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_total_heap_size, 0, ERTS_PI_FLAG_NEED_MSGQ_LEN|ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_suspending, 0, ERTS_PI_FLAG_FORCE_SIG_SEND, 0},
    {am_min_heap_size, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_min_bin_vheap_size, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_max_heap_size, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_current_location, 0, ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_current_stacktrace, 0, ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_message_queue_data, 0, 0, ERTS_PROC_LOCK_MAIN},
    {am_garbage_collection_info, ERTS_PROCESS_GC_INFO_MAX_SIZE, 0, ERTS_PROC_LOCK_MAIN},
    {am_magic_ref, 0, ERTS_PI_FLAG_FORCE_SIG_SEND, ERTS_PROC_LOCK_MAIN},
    {am_fullsweep_after, 0, 0, ERTS_PROC_LOCK_MAIN}
};

#define ERTS_PI_ARGS ((int) (sizeof(pi_args)/sizeof(pi_args[0])))

#ifdef DEBUG
#  define ERTS_PI_DEF_ARR_SZ 2
#else
#  define ERTS_PI_DEF_ARR_SZ ERTS_PI_ARGS
#endif

static ERTS_INLINE Eterm
pi_ix2arg(int ix)
{
    if (ix < 0 || ERTS_PI_ARGS <= ix)
	return am_undefined;
    return pi_args[ix].name;
}

static ERTS_INLINE int
pi_ix2flags(int ix)
{
    if (ix < 0 || ERTS_PI_ARGS <= ix)
	return 0;
    return pi_args[ix].flags;
}

static ERTS_INLINE Uint
pi_ix2rsz(int ix)
{
    if (ix < 0 || ERTS_PI_ARGS <= ix)
	return 0;
    return pi_args[ix].reserve_size;
}

static ERTS_INLINE ErtsProcLocks
pi_ix2locks(int ix)
{
    if (ix < 0 || ERTS_PI_ARGS <= ix)
	return 0;
    return pi_args[ix].locks;
}

static ERTS_INLINE int
pi_arg2ix(Eterm arg)
{
    switch (arg) {
    case am_registered_name:
        return ERTS_PI_IX_REGISTERED_NAME;
    case am_current_function:
        return ERTS_PI_IX_CURRENT_FUNCTION;
    case am_initial_call:
        return ERTS_PI_IX_INITIAL_CALL;
    case am_status:
        return ERTS_PI_IX_STATUS;
    case am_messages:
        return ERTS_PI_IX_MESSAGES;
    case am_message_queue_len:
        return ERTS_PI_IX_MESSAGE_QUEUE_LEN;
    case am_links:
        return ERTS_PI_IX_LINKS;
    case am_monitors:
        return ERTS_PI_IX_MONITORS;
    case am_monitored_by:
        return ERTS_PI_IX_MONITORED_BY;
    case am_dictionary:
        return ERTS_PI_IX_DICTIONARY;
    case am_trap_exit:
        return ERTS_PI_IX_TRAP_EXIT;
    case am_error_handler:
        return ERTS_PI_IX_ERROR_HANDLER;
    case am_heap_size:
        return ERTS_PI_IX_HEAP_SIZE;
    case am_stack_size:
        return ERTS_PI_IX_STACK_SIZE;
    case am_memory:
        return ERTS_PI_IX_MEMORY;
    case am_garbage_collection:
        return ERTS_PI_IX_GARBAGE_COLLECTION;
    case am_group_leader:
        return ERTS_PI_IX_GROUP_LEADER;
    case am_reductions:
        return ERTS_PI_IX_REDUCTIONS;
    case am_priority:
        return ERTS_PI_IX_PRIORITY;
    case am_trace:
        return ERTS_PI_IX_TRACE;
    case am_binary:
        return ERTS_PI_IX_BINARY;
    case am_sequential_trace_token:
        return ERTS_PI_IX_SEQUENTIAL_TRACE_TOKEN;
    case am_catchlevel:
        return ERTS_PI_IX_CATCHLEVEL;
    case am_backtrace:
        return ERTS_PI_IX_BACKTRACE;
    case am_last_calls:
        return ERTS_PI_IX_LAST_CALLS;
    case am_total_heap_size:
        return ERTS_PI_IX_TOTAL_HEAP_SIZE;
    case am_suspending:
        return ERTS_PI_IX_SUSPENDING;
    case am_min_heap_size:
        return ERTS_PI_IX_MIN_HEAP_SIZE;
    case am_min_bin_vheap_size:
        return ERTS_PI_IX_MIN_BIN_VHEAP_SIZE;
    case am_max_heap_size:
        return ERTS_PI_IX_MAX_HEAP_SIZE;
    case am_current_location:
        return ERTS_PI_IX_CURRENT_LOCATION;
    case am_current_stacktrace:
        return ERTS_PI_IX_CURRENT_STACKTRACE;
    case am_message_queue_data:
        return ERTS_PI_IX_MESSAGE_QUEUE_DATA;
    case am_garbage_collection_info:
	return ERTS_PI_IX_GARBAGE_COLLECTION_INFO;
    case am_magic_ref:
        return ERTS_PI_IX_MAGIC_REF;
    case am_fullsweep_after:
        return ERTS_PI_IX_FULLSWEEP_AFTER;
    default:
        return -1;
    }
}

static Eterm pi_1_keys[] = {
    am_registered_name,
    am_current_function,
    am_initial_call,
    am_status,
    am_message_queue_len,
    am_links,
    am_dictionary,
    am_trap_exit,
    am_error_handler,
    am_priority,
    am_group_leader,
    am_total_heap_size,
    am_heap_size,
    am_stack_size,
    am_reductions,
    am_garbage_collection,
    am_suspending
};

#define ERTS_PI_1_NO_OF_KEYS (sizeof(pi_1_keys)/sizeof(Eterm))

static Eterm pi_1_keys_list;
static Eterm pi_1_keys_list_heap[2*ERTS_PI_1_NO_OF_KEYS];

static void
process_info_init(void)
{
    Eterm *hp = &pi_1_keys_list_heap[0];
    int i;

    pi_1_keys_list = NIL;

    for (i = ERTS_PI_1_NO_OF_KEYS-1; i >= 0; i--) {
	pi_1_keys_list = CONS(hp, pi_1_keys[i], pi_1_keys_list);
	hp += 2;
    }

#ifdef DEBUG
    { /* Make sure the process_info argument mappings are consistent */
	int ix;
	for (ix = 0; ix < ERTS_PI_ARGS; ix++) {
	    ASSERT(pi_arg2ix(pi_ix2arg(ix)) == ix);
	}
    }
#endif

}

static BIF_RETTYPE
process_info_aux(Process *c_p,
                 ErtsHeapFactory *hfact,
		 Process *rp,
		 ErtsProcLocks rp_locks,
		 int item_ix,
		 int flags,
                 Uint *reserve_sizep,
                 Uint *reds);

Eterm
erts_process_info(Process *c_p,
                  ErtsHeapFactory *hfact,
                  Process *rp,
                  ErtsProcLocks rp_locks,
                  int *item_ix,
                  int item_ix_len,
                  int flags,
                  Uint reserve_size,
                  Uint *reds)
{
    Eterm res;
    Eterm part_res[ERTS_PI_ARGS];
    int item_ix_ix, ix;

    if (ERTS_PI_FLAG_SINGELTON & flags) {
        ASSERT(item_ix_len == 1);
	res = process_info_aux(c_p, hfact, rp, rp_locks, item_ix[0],
                               flags, &reserve_size, reds);
        return res;
    }

    for (ix = 0; ix < ERTS_PI_ARGS; ix++)
	part_res[ix] = THE_NON_VALUE;

    /*
     * We always handle 'messages' first if it should be part
     * of the result. This since if both 'messages' and
     * 'message_queue_len' are wanted, 'messages' may
     * change the result of 'message_queue_len' (in case
     * the queue contain bad distribution messages).
     */
    if (flags & ERTS_PI_FLAG_WANT_MSGS) {
	ix = pi_arg2ix(am_messages);
	ASSERT(part_res[ix] == THE_NON_VALUE);
	res = process_info_aux(c_p, hfact, rp, rp_locks, ix,
                               flags, &reserve_size, reds);
	ASSERT(res != am_undefined);
	ASSERT(res != THE_NON_VALUE);
        part_res[ix] = res;
    }

    for (item_ix_ix = item_ix_len - 1; item_ix_ix >= 0; item_ix_ix--) {
	ix = item_ix[item_ix_ix];
	if (part_res[ix] == THE_NON_VALUE) {
	    res = process_info_aux(c_p, hfact, rp, rp_locks, ix,
                                   flags, &reserve_size, reds);
            ASSERT(res != am_undefined);
	    ASSERT(res != THE_NON_VALUE);
            part_res[ix] = res;
	}
    }

    res = NIL;

    for (item_ix_ix = item_ix_len - 1; item_ix_ix >= 0; item_ix_ix--) {
	ix = item_ix[item_ix_ix];
	ASSERT(part_res[ix] != THE_NON_VALUE);
	/*
	 * If we should ignore the value of registered_name,
	 * its value is nil. For more info, see comment in the
	 * beginning of process_info_aux().
	 */
	if (is_nil(part_res[ix])) {
	    ASSERT(!(flags & ERTS_PI_FLAG_ALWAYS_WRAP));
	    ASSERT(pi_ix2arg(ix) == am_registered_name);
	}
	else {
            Eterm *hp;
            ERTS_PI_UNRESERVE(reserve_size, 2);
            hp = erts_produce_heap(hfact, 2, reserve_size);
	    res = CONS(hp, part_res[ix], res);
	}
    }

    return res;
}

static void
pi_setup_grow(int **arr, int *def_arr, Uint *sz, int ix);

static BIF_RETTYPE
process_info_bif(Process *c_p, Eterm pid, Eterm opt, int always_wrap, int pi2)
{
    ErtsHeapFactory hfact;
    int def_arr[ERTS_PI_DEF_ARR_SZ];
    int *item_ix = &def_arr[0];
    Process *rp = NULL;
    erts_aint32_t state;
    BIF_RETTYPE ret;
    Uint reds = 0;
    ErtsProcLocks locks = 0;
    int flags;
    Uint reserve_size;
    int len;
    Eterm res;

    ERTS_CT_ASSERT(ERTS_PI_DEF_ARR_SZ > 0);

    if (c_p->common.id == pid) {
        int local_only = c_p->flags & F_LOCAL_SIGS_ONLY;
        int sres, sreds, reds_left;

        reds_left = ERTS_BIF_REDS_LEFT(c_p);
        sreds = reds_left;

        if (!local_only) {
            erts_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ);
            erts_proc_sig_fetch(c_p);
            erts_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ);
        }

        sres = erts_proc_sig_handle_incoming(c_p, &state, &sreds, sreds, !0);

        BUMP_REDS(c_p, (int) sreds);
        reds_left -= sreds;

        if (state & ERTS_PSFLG_EXITING) {
            c_p->flags &= ~F_LOCAL_SIGS_ONLY;
            goto exited;
        }
        if (!sres | (reds_left <= 0)) {
            /*
             * More signals to handle or out of reds; need
             * to yield and continue. Prevent fetching of
             * more signals by setting local-sigs-only flag.
             */
            c_p->flags |= F_LOCAL_SIGS_ONLY;
            goto yield;
        }

        c_p->flags &= ~F_LOCAL_SIGS_ONLY;
    }

    if (is_atom(opt)) {
	int ix = pi_arg2ix(opt);
        item_ix[0] = ix;
        len = 1;
        locks = pi_ix2locks(ix);
        reserve_size = 3 + pi_ix2rsz(ix);
        flags = ERTS_PI_FLAG_SINGELTON;
        flags |= pi_ix2flags(ix);
        if (ix < 0)
            goto badarg;
    }
    else {
        Eterm list = opt;
        Uint size = ERTS_PI_DEF_ARR_SZ;

        len = 0;
        reserve_size = 0;
        locks = 0;
        flags = 0;

        while (is_list(list)) {
            Eterm *consp = list_val(list);
            Eterm arg = CAR(consp);
            int ix = pi_arg2ix(arg);
            if (ix < 0)
                goto badarg;

            if (len >= size)
                pi_setup_grow(&item_ix, def_arr, &size, len);

            item_ix[len++] = ix;

            locks |= pi_ix2locks(ix);
            flags |= pi_ix2flags(ix);
            reserve_size += pi_ix2rsz(ix);
            reserve_size += 3; /* 2-tuple */
            reserve_size += 2; /* cons */

            list = CDR(consp);
        }

        if (is_not_nil(list))
            goto badarg;
    }

    if (is_not_internal_pid(pid)) {
        if (is_external_pid(pid)
            && external_pid_dist_entry(pid) == erts_this_dist_entry)
            goto undefined;
        goto badarg;
    }

    if (always_wrap)
        flags |= ERTS_PI_FLAG_ALWAYS_WRAP;

    if (c_p->common.id == pid) {
        rp = c_p;
        if (locks & ~ERTS_PROC_LOCK_MAIN)
            erts_proc_lock(c_p, locks & ~ERTS_PROC_LOCK_MAIN);
        locks |= ERTS_PROC_LOCK_MAIN;
    }
    else {
        if (flags & ERTS_PI_FLAG_FORCE_SIG_SEND)
            goto send_signal;
        state = ERTS_PSFLG_RUNNING; /* fail state... */
        rp = erts_try_lock_sig_free_proc(pid, locks, &state);
        if (!rp)
            goto undefined;
        if (rp == ERTS_PROC_LOCK_BUSY) {
            rp = NULL;
            goto send_signal;
        }
        if (state & ERTS_PSFLG_EXITING) {
            if (locks)
                erts_proc_unlock(rp, locks);
            locks = 0;
            /* wait for it to terminate properly... */
            goto send_signal;
        }
        if (flags & ERTS_PI_FLAG_NEED_MSGQ_LEN) {
            ASSERT(locks & ERTS_PROC_LOCK_MAIN);
            erts_proc_lock(rp, ERTS_PROC_LOCK_MSGQ);
            erts_proc_sig_fetch(rp);
            if (c_p->sig_qs.cont) {
                erts_proc_unlock(rp, locks|ERTS_PROC_LOCK_MSGQ);
                locks = 0;
                goto send_signal;
            }
            erts_proc_unlock(rp, ERTS_PROC_LOCK_MSGQ);
        }
    }

    erts_factory_proc_init(&hfact, c_p);

    res = erts_process_info(c_p, &hfact, rp, locks, item_ix, len,
                            flags, reserve_size, &reds);

    erts_factory_close(&hfact);

    if (reds > INT_MAX/2)
        reds = INT_MAX/2;
    BUMP_REDS(c_p, (int) reds);

    state = erts_atomic32_read_acqb(&rp->state);
    if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_FREE)) {
        if (state & ERTS_PSFLG_FREE) {
            ASSERT(!locks);
            goto undefined;
        }
        if (locks)
            erts_proc_unlock(rp, locks);
        locks = 0;
        /* wait for it to terminate properly... */
        goto send_signal;
    }

    ERTS_BIF_PREP_RET(ret, res);

done:

    if (c_p == rp)
        locks &= ~ERTS_PROC_LOCK_MAIN;

    if (locks && rp)
	erts_proc_unlock(rp, locks);

    if (item_ix != def_arr)
        erts_free(ERTS_ALC_T_TMP, item_ix);

    return ret;

badarg:
    ERTS_BIF_PREP_ERROR(ret, c_p, BADARG);
    goto done;

undefined:
    ERTS_BIF_PREP_RET(ret, am_undefined);
    goto done;

exited:
    ERTS_BIF_PREP_EXITED(ret, c_p);
    goto done;

yield:
    if (pi2)
        ERTS_BIF_PREP_YIELD2(ret, bif_export[BIF_process_info_2], c_p, pid, opt);
    else
        ERTS_BIF_PREP_YIELD1(ret, bif_export[BIF_process_info_1], c_p, pid);
    goto done;

send_signal: {
        Eterm ref = erts_make_ref(c_p);
        int enqueued, need_msgq_len;
        flags |= ERTS_PI_FLAG_REQUEST_FOR_OTHER;
        need_msgq_len = (flags & ERTS_PI_FLAG_NEED_MSGQ_LEN);
        /*
         * Set receive mark so we wont have to scan the whole
         * message queue for the result. Note caller unconditionally
         * has to enter a receive only matching messages containing
         * 'ref', or restore save pointer.
         */
        ERTS_RECV_MARK_SAVE(c_p);
        ERTS_RECV_MARK_SET(c_p);
        enqueued = erts_proc_sig_send_process_info_request(c_p, pid, item_ix,
                                                           len, need_msgq_len,
                                                           flags, reserve_size,
                                                           ref);
        if (!enqueued) {
            /* Restore save pointer... */
	    JOIN_MESSAGE(c_p);
            goto undefined;
        }
        ERTS_BIF_PREP_TRAP1(ret, erts_await_result, c_p, ref);
        goto done;
    }
}

static void
pi_setup_grow(int **arr, int *def_arr, Uint *sz, int ix)
{
    *sz = (ix+1) + ERTS_PI_DEF_ARR_SZ;
    if (*arr != def_arr)
        *arr = erts_realloc(ERTS_ALC_T_TMP, *arr, (*sz)*sizeof(int));
    else {
        int *new_arr = erts_alloc(ERTS_ALC_T_TMP, (*sz)*sizeof(int));
        sys_memcpy((void *) new_arr, (void *) def_arr,
                   sizeof(int)*ERTS_PI_DEF_ARR_SZ);
        *arr = new_arr;
    }
}


BIF_RETTYPE process_info_2(BIF_ALIST_2)
{
    return process_info_bif(BIF_P, BIF_ARG_1, BIF_ARG_2, !is_atom(BIF_ARG_2), !0);
}

BIF_RETTYPE process_info_1(BIF_ALIST_1)
{
    return process_info_bif(BIF_P, BIF_ARG_1, pi_1_keys_list, 0, 0);
}

Eterm
process_info_aux(Process *c_p,
                 ErtsHeapFactory *hfact,
		 Process *rp,
		 ErtsProcLocks rp_locks,
		 int item_ix,
		 int flags,
                 Uint *reserve_sizep,
                 Uint *reds)
{
    Eterm *hp;
    Eterm res = NIL;
    Uint reserved;
    Uint reserve_size = *reserve_sizep;

#ifdef ERTS_ENABLE_LOCK_CHECK
    ErtsProcLocks locks = erts_proc_lc_my_proc_locks(rp);

    switch (item_ix) {
    case ERTS_PI_IX_STATUS:
    case ERTS_PI_IX_PRIORITY:
    case ERTS_PI_IX_SUSPENDING:
        ERTS_LC_ASSERT((locks & ~ERTS_PROC_LOCK_MAIN) == 0);
        break;
    default:
        ERTS_LC_ASSERT(locks == ERTS_PROC_LOCK_MAIN);
        break;
    }
#endif

    reserved = pi_ix2rsz(item_ix);
    ERTS_PI_UNRESERVE(reserve_size, reserved);

    (*reds)++;

    ASSERT(rp);

    /*
     * Q: Why this ERTS_PI_FLAG_ALWAYS_WRAP flag?
     *
     * A: registered_name is strange. If process has no registered name,
     *    process_info(Pid, registered_name) returns [], and
     *    the result of process_info(Pid) has no {registered_name, Name}
     *    tuple in the resulting list. This is inconsistent with all other
     *    options, but we do not dare to change it.
     *
     *    When process_info/2 is called with a list as second argument,
     *    registered_name behaves as it should, i.e. a
     *    {registered_name, []} will appear in the resulting list.
     *
     *    If ERTS_PI_FLAG_ALWAYS_WRAP is set, process_info_aux() always
     *    wrap the result in a key two tuple. 
     */

    switch (item_ix) {

    case ERTS_PI_IX_REGISTERED_NAME:
	if (rp->common.u.alive.reg)
	    res = rp->common.u.alive.reg->name;
        else {
	    if (flags & ERTS_PI_FLAG_ALWAYS_WRAP)
		res = NIL;
	    else
		return NIL;
	}
	break;

    case ERTS_PI_IX_CURRENT_FUNCTION:
	res = current_function(c_p, hfact, rp, 0,
                               reserve_size, flags);
	break;

    case ERTS_PI_IX_CURRENT_LOCATION:
	res = current_function(c_p, hfact, rp, 1,
                               reserve_size, flags);
	break;

    case ERTS_PI_IX_CURRENT_STACKTRACE:
	res = current_stacktrace(hfact, rp, reserve_size);
	break;

    case ERTS_PI_IX_INITIAL_CALL:
        hp = erts_produce_heap(hfact, 4, reserve_size);
	res = TUPLE3(hp,
		     rp->u.initial.module,
		     rp->u.initial.function,
		     make_small(rp->u.initial.arity));
	hp += 4;
	break;

    case ERTS_PI_IX_STATUS: {
        erts_aint32_t state = erts_atomic32_read_nob(&rp->state);
        res = erts_process_state2status(state);
        if (res == am_running && (state & ERTS_PSFLG_RUNNING_SYS)) {
            ASSERT(c_p == rp);
            ASSERT(flags & ERTS_PI_FLAG_REQUEST_FOR_OTHER);
            if (!(state & (ERTS_PSFLG_SYS_TASKS
                           | ERTS_PSFLG_ACTIVE
                           | ERTS_PSFLG_SIG_Q
                           | ERTS_PSFLG_SIG_IN_Q))) {
                /*
                 * We are servicing a process-info request from
                 * another process. If that other process could
                 * have inspected our state itself, we would have
                 * been in the 'waiting' state.
                 */
                res = am_waiting;
            }
        }
	break;
    }

    case ERTS_PI_IX_MESSAGES: {
        ASSERT(flags & ERTS_PI_FLAG_NEED_MSGQ_LEN);
	if (rp->sig_qs.len == 0 || (ERTS_TRACE_FLAGS(rp) & F_SENSITIVE))
            res = NIL;
        else {
            int info_on_self = !(flags & ERTS_PI_FLAG_REQUEST_FOR_OTHER);
	    ErtsMessageInfo *mip;
	    Sint i, len;
	    Uint heap_need;

	    mip = erts_alloc(ERTS_ALC_T_TMP,
			     rp->sig_qs.len*sizeof(ErtsMessageInfo));

	    /*
	     * Note that message queue may shrink when calling
	     * erts_proc_sig_prep_msgq_for_inspection() since it removes
	     * corrupt distribution messages.
	     */
	    heap_need = erts_proc_sig_prep_msgq_for_inspection(c_p, rp,
                                                               rp_locks,
                                                               info_on_self,
                                                               mip);
            len = rp->sig_qs.len;

	    heap_need += len*2; /* Cons cells */

            reserve_size += heap_need;

	    /* Build list of messages... */
	    for (i = len - 1, res = NIL; i >= 0; i--) {
		Eterm msg = ERL_MESSAGE_TERM(mip[i].msgp);
		Uint sz = mip[i].size;

                ERTS_PI_UNRESERVE(reserve_size, sz+2);
                hp = erts_produce_heap(hfact, sz+2, reserve_size);

		if (sz != 0)
		    msg = copy_struct(msg, sz, &hp, hfact->off_heap);

		res = CONS(hp, msg, res);
		hp += 2;
	    }

            *reds += (Uint) len / 4;

	    erts_free(ERTS_ALC_T_TMP, mip);
	}
	break;
    }

    case ERTS_PI_IX_MESSAGE_QUEUE_LEN: {
        Sint len = rp->sig_qs.len;
        ASSERT(flags & ERTS_PI_FLAG_NEED_MSGQ_LEN);
        ASSERT(len >= 0);
        if (len <= MAX_SMALL)
            res = make_small(len);
        else {
            hp = erts_produce_heap(hfact, BIG_UINT_HEAP_SIZE, reserve_size);
            res = uint_to_big((Uint) len, hp);
        }
	break;
    }

    case ERTS_PI_IX_LINKS: {
	MonitorInfoCollection mic;
	int i;
	Eterm item;

	INIT_MONITOR_INFOS(mic);

	erts_link_tree_foreach(ERTS_P_LINKS(rp), collect_one_link, (void *) &mic);

        reserve_size += mic.sz;
	res = NIL;
	for (i = 0; i < mic.mi_i; i++) {
            Eterm item_src = mic.mi[i].entity.term;
            Uint sz = NC_HEAP_SIZE(item_src) + 2;
            ERTS_PI_UNRESERVE(reserve_size, sz);
            hp = erts_produce_heap(hfact, sz, reserve_size);
	    item = STORE_NC(&hp, hfact->off_heap, item_src); 
	    res = CONS(hp, item, res);
	}

        *reds += (Uint) mic.mi_i / 4;

	DESTROY_MONITOR_INFOS(mic);
	break;
    }

    case ERTS_PI_IX_MONITORS: {
	MonitorInfoCollection mic;
        int i;

	INIT_MONITOR_INFOS(mic);
        erts_monitor_tree_foreach(ERTS_P_MONITORS(rp),
                                  collect_one_origin_monitor,
                                  (void *) &mic);

        reserve_size += mic.sz;
	res = NIL;
	for (i = 0; i < mic.mi_i; i++) {
	    if (mic.mi[i].named) {
		/* Monitor by name. 
                 * Build {process|port, {Name, Node}} and cons it.
		 */
		Eterm t1, t2;
                /* If pid is an atom, then it is a remote named monitor, which
                   has to be a process */
                Eterm m_type = is_port(mic.mi[i].pid) ? am_port : am_process;
                ASSERT(is_pid(mic.mi[i].pid)
                    || is_port(mic.mi[i].pid)
                    || is_atom(mic.mi[i].pid));

                ERTS_PI_UNRESERVE(reserve_size, 3+3+2);
                hp = erts_produce_heap(hfact, 3+3+2, reserve_size);

		t1 = TUPLE2(hp, mic.mi[i].entity.term, mic.mi[i].node);
		hp += 3;
                t2 = TUPLE2(hp, m_type, t1);
		hp += 3;
		res = CONS(hp, t2, res);
	    }
	    else {
                /* Build {process|port|time_offset, Pid|clock_service} and cons it. */
		Eterm t;
		Eterm pid;
                Eterm m_type;
                Eterm pid_src = mic.mi[i].entity.term;
                Uint sz = is_atom(pid_src) ? 0 : NC_HEAP_SIZE(pid_src);
                sz += 3 + 2;

                ERTS_PI_UNRESERVE(reserve_size, sz);
                hp = erts_produce_heap(hfact, sz, reserve_size);

                pid = (is_atom(pid_src)
                       ? pid_src
                       : STORE_NC(&hp, hfact->off_heap, pid_src));

                switch (mic.mi[i].type) {
                case ERTS_MON_TYPE_PORT:
                    m_type = am_port;
                    break;
                case ERTS_MON_TYPE_TIME_OFFSET:
                    m_type = am_time_offset;
                    break;
                default:
                    m_type = am_process;
                    break;
                }

                ASSERT(is_pid(mic.mi[i].pid)
                    || is_port(mic.mi[i].pid));

                t = TUPLE2(hp, m_type, pid);
		hp += 3;
		res = CONS(hp, t, res);
	    }
	}

        *reds += (Uint) mic.mi_i / 4;

        DESTROY_MONITOR_INFOS(mic);
	break;
    }

    case ERTS_PI_IX_MONITORED_BY: {
	MonitorInfoCollection mic;
	int i;
	Eterm item;

	INIT_MONITOR_INFOS(mic);
        erts_monitor_list_foreach(ERTS_P_LT_MONITORS(rp),
                                  collect_one_target_monitor,
                                  (void *) &mic);
        erts_monitor_tree_foreach(ERTS_P_MONITORS(rp),
                                  collect_one_target_monitor,
                                  (void *) &mic);

        reserve_size += mic.sz;

	res = NIL;
	for (i = 0; i < mic.mi_i; ++i) {
            Uint sz = 2;

            if (mic.mi[i].type == ERTS_MON_TYPE_RESOURCE)
                sz += erts_resource_ref_size(mic.mi[i].entity.resource);
            else
                sz += NC_HEAP_SIZE(mic.mi[i].entity.term);

            ERTS_PI_UNRESERVE(reserve_size, sz);
            hp = erts_produce_heap(hfact, sz, reserve_size);

            if (mic.mi[i].type == ERTS_MON_TYPE_RESOURCE)
                item = erts_bld_resource_ref(&hp,
                                             hfact->off_heap,
                                             mic.mi[i].entity.resource);
            else
                item = STORE_NC(&hp,
                                hfact->off_heap,
                                mic.mi[i].entity.term);
	    res = CONS(hp, item, res);
	}

        *reds += (Uint) mic.mi_i / 4;

	DESTROY_MONITOR_INFOS(mic);
	break;
    }

    case ERTS_PI_IX_SUSPENDING: {
	ErtsSuspendMonitorInfoCollection smic;
	int i;

	ERTS_INIT_SUSPEND_MONITOR_INFOS(smic);

        erts_monitor_tree_foreach(ERTS_P_MONITORS(rp),
                                  collect_one_suspend_monitor,
                                  (void *) &smic);

        reserve_size += smic.sz;

	res = NIL;
	for (i = 0; i < smic.smi_i; i++) {
            ErtsMonitorSuspend *msp;
            erts_aint_t mstate;
	    Sint ci;
            Eterm ct, active, pending, item;
            Uint sz = 4 + 2;

            msp = smic.smi[i];
            mstate = erts_atomic_read_nob(&msp->state);

            ci = (Sint) (mstate & ERTS_MSUSPEND_STATE_COUNTER_MASK);
            if (!IS_SSMALL(ci))
                sz += BIG_UINT_HEAP_SIZE;

            ERTS_PI_UNRESERVE(reserve_size, sz);
            hp = erts_produce_heap(hfact, sz, reserve_size);

            if (IS_SSMALL(ci))
                ct = make_small(ci);
            else {
                ct = small_to_big(ci, hp);
                hp += BIG_UINT_HEAP_SIZE;
            }

            if (mstate & ERTS_MSUSPEND_STATE_FLG_ACTIVE) {
                active = ct;
                pending = make_small(0);
            }
            else {
                active = make_small(0);
                pending = ct;
            }

            ASSERT(is_internal_pid(msp->md.origin.other.item));

	    item = TUPLE3(hp, msp->md.origin.other.item, active, pending);
	    hp += 4;
	    res = CONS(hp, item, res);
	}

        *reds += (Uint) smic.smi_i / 4;

	ERTS_DESTROY_SUSPEND_MONITOR_INFOS(smic);

	break;
    }

    case ERTS_PI_IX_DICTIONARY:
	if (!rp->dictionary || (ERTS_TRACE_FLAGS(rp) & F_SENSITIVE)) {
	    res = NIL;
	} else {
            Uint num = rp->dictionary->numElements;
	    res = erts_dictionary_copy(hfact, rp->dictionary, reserve_size);
            *reds += (Uint) num / 4;
	}

	break;

    case ERTS_PI_IX_TRAP_EXIT:
        res = (rp->flags & F_TRAP_EXIT) ? am_true : am_false;
	break;

    case ERTS_PI_IX_ERROR_HANDLER:
	res = erts_proc_get_error_handler(rp);
	break;

    case ERTS_PI_IX_HEAP_SIZE: {
	Uint hsz = 0;
	(void) erts_bld_uint(NULL, &hsz, HEAP_SIZE(rp));
        hp = erts_produce_heap(hfact, hsz, reserve_size);
	res = erts_bld_uint(&hp, NULL, HEAP_SIZE(rp));
	break;
    }

    case ERTS_PI_IX_FULLSWEEP_AFTER: {
	Uint hsz = 0;
	(void) erts_bld_uint(NULL, &hsz, MAX_GEN_GCS(rp));
        hp = erts_produce_heap(hfact, hsz, reserve_size);
	res = erts_bld_uint(&hp, NULL, MAX_GEN_GCS(rp));
	break;
    }

    case ERTS_PI_IX_MIN_HEAP_SIZE: {
	Uint hsz = 0;
	(void) erts_bld_uint(NULL, &hsz, MIN_HEAP_SIZE(rp));
        hp = erts_produce_heap(hfact, hsz, reserve_size);
	res = erts_bld_uint(&hp, NULL, MIN_HEAP_SIZE(rp));
	break;
    }

    case ERTS_PI_IX_MIN_BIN_VHEAP_SIZE: {
	Uint hsz = 0;
	(void) erts_bld_uint(NULL, &hsz, MIN_VHEAP_SIZE(rp));
        hp = erts_produce_heap(hfact, hsz, reserve_size);
	res = erts_bld_uint(&hp, NULL, MIN_VHEAP_SIZE(rp));
	break;
    }

    case ERTS_PI_IX_MAX_HEAP_SIZE: {
	Uint hsz = 0;
	(void) erts_max_heap_size_map(MAX_HEAP_SIZE_GET(rp),
                                      MAX_HEAP_SIZE_FLAGS_GET(rp),
                                      NULL, &hsz);
        hp = er…