Libc-825.40.1.tar.gz

[apple/libc.git] / gen / malloc.c

/*
 * Copyright (c) 1999, 2006-2008 Apple Inc. All rights reserved.
 *
 * @APPLE_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. 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_LICENSE_HEADER_END@
 */
 
#include <pthread_internals.h>
#include "magmallocProvider.h"
#include <mach-o/dyld.h>        /* for NSVersionOfLinkTimeLibrary() */

#import <stdlib.h>
#import <stdio.h>
#import <string.h>
#import <unistd.h>
#import <malloc/malloc.h>
#import <fcntl.h>
#import <crt_externs.h>
#import <errno.h>
#import <pthread_internals.h>
#import <limits.h>
#import <dlfcn.h>
#import <mach/mach_vm.h>
#import <mach/mach_init.h>
#import <sys/mman.h>

#import "scalable_malloc.h"
#import "stack_logging.h"
#import "malloc_printf.h"
#import "_simple.h"
#import "CrashReporterClient.h"

/*
 * MALLOC_ABSOLUTE_MAX_SIZE - There are many instances of addition to a
 * user-specified size_t, which can cause overflow (and subsequent crashes)
 * for values near SIZE_T_MAX.  Rather than add extra "if" checks everywhere
 * this occurs, it is easier to just set an absolute maximum request size,
 * and immediately return an error if the requested size exceeds this maximum.
 * Of course, values less than this absolute max can fail later if the value
 * is still too large for the available memory.  The largest value added
 * seems to be PAGE_SIZE (in the macro round_page()), so to be safe, we set
 * the maximum to be 2 * PAGE_SIZE less than SIZE_T_MAX.
 */
#define MALLOC_ABSOLUTE_MAX_SIZE        (SIZE_T_MAX - (2 * PAGE_SIZE))

#define USE_SLEEP_RATHER_THAN_ABORT     0

typedef void (malloc_logger_t)(uint32_t type, uintptr_t arg1, uintptr_t arg2, uintptr_t arg3, uintptr_t result, uint32_t num_hot_frames_to_skip);

__private_extern__ pthread_lock_t _malloc_lock = 0; // initialized in __libc_init

/* The following variables are exported for the benefit of performance tools
 *
 * It should always be safe to first read malloc_num_zones, then read
 * malloc_zones without taking the lock, if only iteration is required and
 * provided that when malloc_destroy_zone is called all prior operations on that
 * zone are complete and no further calls referencing that zone can be made.
 */
unsigned malloc_num_zones = 0;
unsigned malloc_num_zones_allocated = 0;
malloc_zone_t **malloc_zones = 0;
malloc_logger_t *malloc_logger = NULL;

unsigned malloc_debug_flags = 0;

unsigned malloc_check_start = 0; // 0 means don't check
unsigned malloc_check_counter = 0;
unsigned malloc_check_each = 1000;

/* global flag to suppress ASL logging e.g. for syslogd */
int _malloc_no_asl_log = 0;

static int malloc_check_sleep = 100; // default 100 second sleep
static int malloc_check_abort = 0; // default is to sleep, not abort

static int malloc_debug_file = STDERR_FILENO;
/*
 * State indicated by malloc_def_zone_state
 * 0 - the default zone has not yet been created
 * 1 - a Malloc* environment variable has been set
 * 2 - the default zone has been created and an environment variable scan done
 * 3 - a new default zone has been created and another environment variable scan
 */
__private_extern__ int malloc_def_zone_state = 0;

static const char Malloc_Facility[] = "com.apple.Libsystem.malloc";

#define MALLOC_LOCK()           LOCK(_malloc_lock)
#define MALLOC_UNLOCK()         UNLOCK(_malloc_lock)

/*
 * Counters that coordinate zone destruction (in malloc_zone_unregister) with
 * find_registered_zone (here abbreviated as FRZ).
 */
static int counterAlice = 0, counterBob = 0;
static int *pFRZCounterLive= &counterAlice, *pFRZCounterDrain = &counterBob;

#define MALLOC_LOG_TYPE_ALLOCATE        stack_logging_type_alloc
#define MALLOC_LOG_TYPE_DEALLOCATE      stack_logging_type_dealloc
#define MALLOC_LOG_TYPE_HAS_ZONE        stack_logging_flag_zone
#define MALLOC_LOG_TYPE_CLEARED         stack_logging_flag_cleared

/*********      Utilities       ************/
__private_extern__ uint64_t malloc_entropy[2] = {0, 0};

void __malloc_entropy_setup(const char *apple[]) __attribute__ ((visibility ("hidden")));

static int
__entropy_from_kernel(const char *str)
{
    unsigned long long val;
    char tmp[20], *p;
    int idx = 0;

    /* Skip over key to the first value */
    str = strchr(str, '=');
    if (str == NULL)
        return 0;
    str++;

    while (str && idx < sizeof(malloc_entropy)/sizeof(malloc_entropy[0])) {
        strlcpy(tmp, str, 20);
        p = strchr(tmp, ',');
        if (p) *p = '\0';
        val = strtoull(tmp, NULL, 0);
        malloc_entropy[idx] = (uint64_t)val;
        idx++;
        if ((str = strchr(str, ',')) != NULL)
            str++;
    }
    return idx;
}

void
__malloc_entropy_setup(const char *apple[])
{
    const char **p;
    for (p = apple; p && *p; p++) {
        if (strstr(*p, "malloc_entropy") == *p) {
            if (sizeof(malloc_entropy)/sizeof(malloc_entropy[0]) == __entropy_from_kernel(*p))
                return;
            else
                break;
        }
    }

    malloc_entropy[0] = ((uint64_t)arc4random()) << 32 | ((uint64_t)arc4random());
    malloc_entropy[1] = ((uint64_t)arc4random()) << 32 | ((uint64_t)arc4random());
    return;
}

static inline malloc_zone_t * find_registered_zone(const void *, size_t *) __attribute__((always_inline));
static inline malloc_zone_t *
find_registered_zone(const void *ptr, size_t *returned_size) {
    // Returns a zone which contains ptr, else NULL
 
    if (0 == malloc_num_zones) {
        if (returned_size) *returned_size = 0;
        return NULL;
    }

    // The default zone is registered in malloc_zones[0]. There's no danger that it will ever be unregistered.
    // So don't advance the FRZ counter yet.
    malloc_zone_t *zone = malloc_zones[0];
    size_t size = zone->size(zone, ptr);
    if (size) { // Claimed by this zone?
        if (returned_size) *returned_size = size;
        return zone;
    }

    int *pFRZCounter = pFRZCounterLive; // Capture pointer to the counter of the moment
    __sync_fetch_and_add(pFRZCounter, 1); // Advance this counter -- our thread is in FRZ
    
    unsigned            index;
    unsigned            limit = malloc_num_zones;
    malloc_zone_t       **zones = &malloc_zones[1];
    
    for (index = 1; index < limit; ++index, ++zones) {
        zone = *zones;
        size = zone->size(zone, ptr);
        if (size) { // Claimed by this zone?
            if (returned_size) *returned_size = size;
            __sync_fetch_and_sub(pFRZCounter, 1); // our thread is leaving FRZ
            return zone;
        }
    }
    // Unclaimed by any zone.
    if (returned_size) *returned_size = 0;
    __sync_fetch_and_sub(pFRZCounter, 1); // our thread is leaving FRZ
    return NULL;
}

__private_extern__ __attribute__((noinline)) void
malloc_error_break(void) {
        // Provides a non-inlined place for various malloc error procedures to call
        // that will be called after an error message appears.  It does not make
        // sense for developers to call this function, so it is marked
        // __private_extern__ to prevent it from becoming API.
        MAGMALLOC_MALLOCERRORBREAK(); // DTrace USDT probe
}

__private_extern__ boolean_t __stack_logging_locked();

__private_extern__ __attribute__((noinline)) __attribute__((used)) int
malloc_gdb_po_unsafe(void) {
  // In order to implement "po" other data formatters in gdb, the debugger
  // calls functions that call malloc.  The debugger will  only run one thread 
  // of the program in this case, so if another thread is holding a zone lock,
  // gdb may deadlock in this case.
  //
  // Iterate over the zones in malloc_zones, and call "trylock" on the zone 
  // lock.  If trylock succeeds, unlock it, otherwise return "locked".  Returns
  // 0 == safe, 1 == locked/unsafe.
  
  if (__stack_logging_locked())
    return 1;

  malloc_zone_t **zones = malloc_zones;
  unsigned i, e = malloc_num_zones;
  
  for (i = 0; i != e; ++i) {
    malloc_zone_t *zone = zones[i];

    // Version must be >= 5 to look at the new introspection field.
    if (zone->version < 5)
      continue;

    if (zone->introspect->zone_locked && zone->introspect->zone_locked(zone))
      return 1;
  }
  return 0;
}

/*********      Creation and destruction        ************/

static void set_flags_from_environment(void);

static void
malloc_zone_register_while_locked(malloc_zone_t *zone) {
    size_t protect_size;
    unsigned i;
    
    /* scan the list of zones, to see if this zone is already registered.  If
     * so, print an error message and return. */
    for (i = 0; i != malloc_num_zones; ++i)
        if (zone == malloc_zones[i]) {
            _malloc_printf(ASL_LEVEL_ERR, "Attempted to register zone more than once: %p\n", zone);
            return;
        }
  
    if (malloc_num_zones == malloc_num_zones_allocated) {
        size_t malloc_zones_size = malloc_num_zones * sizeof(malloc_zone_t *);
        size_t alloc_size = malloc_zones_size + vm_page_size;
        
        malloc_zone_t **new_zones = mmap(0, alloc_size, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, VM_MAKE_TAG(VM_MEMORY_MALLOC), 0);
        
        /* If there were previously allocated malloc zones, we need to copy them
         * out of the previous array and into the new zones array */
        if (malloc_zones)
            memcpy(new_zones, malloc_zones, malloc_zones_size);
            
        /* Update the malloc_zones pointer, which we leak if it was previously
         * allocated, and the number of zones allocated */
        protect_size = alloc_size;
        malloc_zones = new_zones;
        malloc_num_zones_allocated = alloc_size / sizeof(malloc_zone_t *);
    } else {
        /* If we don't need to reallocate zones, we need to briefly change the
         * page protection the malloc zones to allow writes */
        protect_size = malloc_num_zones_allocated * sizeof(malloc_zone_t *);
        mprotect(malloc_zones, protect_size, PROT_READ | PROT_WRITE);
    }
    malloc_zones[malloc_num_zones++] = zone;
    
    /* Finally, now that the zone is registered, disallow write access to the
     * malloc_zones array */
    mprotect(malloc_zones, protect_size, PROT_READ);
    //_malloc_printf(ASL_LEVEL_INFO, "Registered malloc_zone %p in malloc_zones %p [%u zones, %u bytes]\n", zone, malloc_zones, malloc_num_zones, protect_size);
}

static void
_malloc_initialize(void) {
    MALLOC_LOCK();
    if (malloc_def_zone_state < 2) {
        unsigned n;
        malloc_zone_t   *zone;

        malloc_def_zone_state += 2;
        set_flags_from_environment(); // will only set flags up to two times
        n = malloc_num_zones;
        zone = create_scalable_zone(0, malloc_debug_flags);
        malloc_zone_register_while_locked(zone);
        malloc_set_zone_name(zone, "DefaultMallocZone");
        if (n != 0) { // make the default first, for efficiency
                unsigned protect_size = malloc_num_zones_allocated * sizeof(malloc_zone_t *);
                malloc_zone_t *hold = malloc_zones[0];
                
                if(hold->zone_name && strcmp(hold->zone_name, "DefaultMallocZone") == 0) {
                malloc_set_zone_name(hold, NULL);
                }
                
                mprotect(malloc_zones, protect_size, PROT_READ | PROT_WRITE);
                malloc_zones[0] = malloc_zones[n];
                malloc_zones[n] = hold;
                mprotect(malloc_zones, protect_size, PROT_READ);
        }
        // _malloc_printf(ASL_LEVEL_INFO, "%d registered zones\n", malloc_num_zones);
        // _malloc_printf(ASL_LEVEL_INFO, "malloc_zones is at %p; malloc_num_zones is at %p\n", (unsigned)&malloc_zones, (unsigned)&malloc_num_zones);
    }
    MALLOC_UNLOCK();
}

static inline malloc_zone_t *inline_malloc_default_zone(void) __attribute__((always_inline));
static inline malloc_zone_t *
inline_malloc_default_zone(void) {
    if (malloc_def_zone_state < 2) _malloc_initialize();
    // _malloc_printf(ASL_LEVEL_INFO, "In inline_malloc_default_zone with %d %d\n", malloc_num_zones, malloc_has_debug_zone);
    return malloc_zones[0];
}

malloc_zone_t *
malloc_default_zone(void) {
    return inline_malloc_default_zone();
}

static inline malloc_zone_t *inline_malloc_default_scalable_zone(void) __attribute__((always_inline));
static inline malloc_zone_t *
inline_malloc_default_scalable_zone(void) {
    unsigned index;

    if (malloc_def_zone_state < 2) _malloc_initialize();
    // _malloc_printf(ASL_LEVEL_INFO, "In inline_malloc_default_scalable_zone with %d %d\n", malloc_num_zones, malloc_has_debug_zone);

    MALLOC_LOCK();
    for (index = 0; index < malloc_num_zones; ++index) {
        malloc_zone_t *z = malloc_zones[index];

        if(z->zone_name && strcmp(z->zone_name, "DefaultMallocZone") == 0) {
            MALLOC_UNLOCK();
            return z;
        }
    }
    MALLOC_UNLOCK();

    malloc_printf("*** malloc_default_scalable_zone() failed to find 'DefaultMallocZone'\n");
    return NULL; // FIXME: abort() instead?
}

malloc_zone_t *
malloc_default_purgeable_zone(void) {
    static malloc_zone_t *dpz;

    if (!dpz) {
        //
        // PR_7288598: Must pass a *scalable* zone (szone) as the helper for create_purgeable_zone().
        // Take care that the zone so obtained is not subject to interposing.
        //
        malloc_zone_t *tmp = create_purgeable_zone(0, inline_malloc_default_scalable_zone(), malloc_debug_flags);
        malloc_zone_register(tmp);
        malloc_set_zone_name(tmp, "DefaultPurgeableMallocZone");
        if (!__sync_bool_compare_and_swap(&dpz, NULL, tmp))
            malloc_destroy_zone(tmp);
    }
    return dpz;
}

// For debugging, allow stack logging to both memory and disk to compare their results.
static void
stack_logging_log_stack_debug(uint32_t type_flags, uintptr_t zone_ptr, uintptr_t size, uintptr_t ptr_arg, uintptr_t return_val, uint32_t num_hot_to_skip)
{
    __disk_stack_logging_log_stack(type_flags, zone_ptr, size, ptr_arg, return_val, num_hot_to_skip);
    stack_logging_log_stack(type_flags, zone_ptr, size, ptr_arg, return_val, num_hot_to_skip);
}

static void
set_flags_from_environment(void) {
    const char  *flag;
    int         fd;
    char        **env = * _NSGetEnviron();
    char        **p;
    char        *c;

    if (malloc_debug_file != STDERR_FILENO) {
        close(malloc_debug_file);
        malloc_debug_file = STDERR_FILENO;
    }
#if __LP64__
    malloc_debug_flags = SCALABLE_MALLOC_ABORT_ON_CORRUPTION; // Set always on 64-bit processes
#else
    int libSystemVersion  = NSVersionOfLinkTimeLibrary("System");
    if ((-1 != libSystemVersion) && ((libSystemVersion >> 16) < 126) /* Lion or greater */)
        malloc_debug_flags = 0;
    else
        malloc_debug_flags = SCALABLE_MALLOC_ABORT_ON_CORRUPTION;
#endif
    stack_logging_enable_logging = 0;
    stack_logging_dontcompact = 0;
    malloc_logger = NULL;
    malloc_check_start = 0;
    malloc_check_each = 1000;
    malloc_check_abort = 0;
    malloc_check_sleep = 100;
    /*
     * Given that all environment variables start with "Malloc" we optimize by scanning quickly
     * first the environment, therefore avoiding repeated calls to getenv().
     * If we are setu/gid these flags are ignored to prevent a malicious invoker from changing
     * our behaviour.
     */
    for (p = env; (c = *p) != NULL; ++p) {
        if (!strncmp(c, "Malloc", 6)) {
            if (issetugid())
                return;
            break;
        }
    }
    if (c == NULL)
        return;
    flag = getenv("MallocLogFile");
    if (flag) {
        fd = open(flag, O_WRONLY|O_APPEND|O_CREAT, 0644);
        if (fd >= 0) {
           malloc_debug_file = fd;
           fcntl(fd, F_SETFD, 0); // clear close-on-exec flag  XXX why?
        } else {
            malloc_printf("Could not open %s, using stderr\n", flag);
        }
    }
    if (getenv("MallocGuardEdges")) {
        malloc_debug_flags |= SCALABLE_MALLOC_ADD_GUARD_PAGES;
        _malloc_printf(ASL_LEVEL_INFO, "protecting edges\n");
        if (getenv("MallocDoNotProtectPrelude")) {
            malloc_debug_flags |= SCALABLE_MALLOC_DONT_PROTECT_PRELUDE;
            _malloc_printf(ASL_LEVEL_INFO, "... but not protecting prelude guard page\n");
        }
        if (getenv("MallocDoNotProtectPostlude")) {
            malloc_debug_flags |= SCALABLE_MALLOC_DONT_PROTECT_POSTLUDE;
            _malloc_printf(ASL_LEVEL_INFO, "... but not protecting postlude guard page\n");
        }
    }
    flag = getenv("MallocStackLogging");
    if (!flag) {
        flag = getenv("MallocStackLoggingNoCompact");
        stack_logging_dontcompact = 1;
    } 
    // For debugging, the MallocStackLogging or MallocStackLoggingNoCompact environment variables can be set to
    // values of "memory", "disk", or "both" to control which stack logging mechanism to use.  Those strings appear
    // in the flag variable, and the strtoul() call below will return 0, so then we can do string comparison on the
    // value of flag.  The default stack logging now is disk stack logging, since memory stack logging is not 64-bit-aware.
    if (flag) {
        unsigned long val = strtoul(flag, NULL, 0);
        if (val == 1) val = 0;
        if (val == -1) val = 0;
        if (val) {
            malloc_logger = (void *)val;
            _malloc_printf(ASL_LEVEL_INFO, "recording stacks using recorder %p\n", malloc_logger);
        } else if (strcmp(flag,"memory") == 0) {
            malloc_logger = (malloc_logger_t *)stack_logging_log_stack;
            _malloc_printf(ASL_LEVEL_INFO, "recording malloc stacks in memory using standard recorder\n");
        } else if (strcmp(flag,"both") == 0) {
            malloc_logger = stack_logging_log_stack_debug;
            _malloc_printf(ASL_LEVEL_INFO, "recording malloc stacks to both memory and disk for comparison debugging\n");
        } else {        // the default is to log to disk
            malloc_logger = __disk_stack_logging_log_stack;
            _malloc_printf(ASL_LEVEL_INFO, "recording malloc stacks to disk using standard recorder\n");
        }
        stack_logging_enable_logging = 1;
        if (stack_logging_dontcompact) {
            if (malloc_logger == __disk_stack_logging_log_stack) {
              _malloc_printf(ASL_LEVEL_INFO, "stack logging compaction turned off; size of log files on disk can increase rapidly\n");
            } else {
              _malloc_printf(ASL_LEVEL_INFO, "stack logging compaction turned off; VM can increase rapidly\n");
            }
        }
    }
    if (getenv("MallocScribble")) {
        malloc_debug_flags |= SCALABLE_MALLOC_DO_SCRIBBLE;
        _malloc_printf(ASL_LEVEL_INFO, "enabling scribbling to detect mods to free blocks\n");
    }
    if (getenv("MallocErrorAbort")) {
        malloc_debug_flags |= SCALABLE_MALLOC_ABORT_ON_ERROR;
        _malloc_printf(ASL_LEVEL_INFO, "enabling abort() on bad malloc or free\n");
    }
#if __LP64__
    /* initialization above forces SCALABLE_MALLOC_ABORT_ON_CORRUPTION of 64-bit processes */
#else
    flag = getenv("MallocCorruptionAbort");
    if (flag && (flag[0] == '0')) { // Set from an environment variable in 32-bit processes
        malloc_debug_flags &= ~SCALABLE_MALLOC_ABORT_ON_CORRUPTION;
    } else if (flag) {
        malloc_debug_flags |= SCALABLE_MALLOC_ABORT_ON_CORRUPTION;
    }
#endif
    flag = getenv("MallocCheckHeapStart");
    if (flag) {
        malloc_check_start = strtoul(flag, NULL, 0);
        if (malloc_check_start == 0) malloc_check_start = 1;
        if (malloc_check_start == -1) malloc_check_start = 1;
        flag = getenv("MallocCheckHeapEach");
        if (flag) {
            malloc_check_each = strtoul(flag, NULL, 0);
            if (malloc_check_each == 0) malloc_check_each = 1;
            if (malloc_check_each == -1) malloc_check_each = 1;
        }
        _malloc_printf(ASL_LEVEL_INFO, "checks heap after %dth operation and each %d operations\n", malloc_check_start, malloc_check_each);
        flag = getenv("MallocCheckHeapAbort");
        if (flag)
            malloc_check_abort = strtol(flag, NULL, 0);
        if (malloc_check_abort)
            _malloc_printf(ASL_LEVEL_INFO, "will abort on heap corruption\n");
        else {
            flag = getenv("MallocCheckHeapSleep");
            if (flag)
                malloc_check_sleep = strtol(flag, NULL, 0);
            if (malloc_check_sleep > 0)
                _malloc_printf(ASL_LEVEL_INFO, "will sleep for %d seconds on heap corruption\n", malloc_check_sleep);
            else if (malloc_check_sleep < 0)
                _malloc_printf(ASL_LEVEL_INFO, "will sleep once for %d seconds on heap corruption\n", -malloc_check_sleep);
            else
                _malloc_printf(ASL_LEVEL_INFO, "no sleep on heap corruption\n");
        }
    }
    if (getenv("MallocHelp")) {
        _malloc_printf(ASL_LEVEL_INFO,
            "environment variables that can be set for debug:\n"
            "- MallocLogFile <f> to create/append messages to file <f> instead of stderr\n"
            "- MallocGuardEdges to add 2 guard pages for each large block\n"
            "- MallocDoNotProtectPrelude to disable protection (when previous flag set)\n"
            "- MallocDoNotProtectPostlude to disable protection (when previous flag set)\n"
            "- MallocStackLogging to record all stacks.  Tools like leaks can then be applied\n"
            "- MallocStackLoggingNoCompact to record all stacks.  Needed for malloc_history\n"
            "- MallocStackLoggingDirectory to set location of stack logs, which can grow large; default is /tmp\n"
            "- MallocScribble to detect writing on free blocks and missing initializers:\n"
            "  0x55 is written upon free and 0xaa is written on allocation\n"
            "- MallocCheckHeapStart <n> to start checking the heap after <n> operations\n"
            "- MallocCheckHeapEach <s> to repeat the checking of the heap after <s> operations\n"
            "- MallocCheckHeapSleep <t> to sleep <t> seconds on heap corruption\n"
            "- MallocCheckHeapAbort <b> to abort on heap corruption if <b> is non-zero\n"
            "- MallocCorruptionAbort to abort on malloc errors, but not on out of memory for 32-bit processes\n"
            "  MallocCorruptionAbort is always set on 64-bit processes\n"
            "- MallocErrorAbort to abort on any malloc error, including out of memory\n"
            "- MallocHelp - this help!\n");
    }
}

malloc_zone_t *
malloc_create_zone(vm_size_t start_size, unsigned flags)
{
    malloc_zone_t       *zone;

    /* start_size doesn't seemed to actually be used, but we test anyways */
    if (start_size > MALLOC_ABSOLUTE_MAX_SIZE) {
        return NULL;
    }
    if (malloc_def_zone_state < 2) _malloc_initialize();
    zone = create_scalable_zone(start_size, flags | malloc_debug_flags);
    malloc_zone_register(zone);
    return zone;
}

/*
 * For use by CheckFix: establish a new default zone whose behavior is, apart from
 * the use of death-row and per-CPU magazines, that of Leopard.
 */
void
malloc_create_legacy_default_zone(void)
{
    malloc_zone_t       *zone;
    int i;

    if (malloc_def_zone_state < 2) _malloc_initialize();
    zone = create_legacy_scalable_zone(0, malloc_debug_flags);

    MALLOC_LOCK();
    malloc_zone_register_while_locked(zone);

    //
    // Establish the legacy scalable zone just created as the default zone.
    //
    malloc_zone_t *hold = malloc_zones[0];
    if(hold->zone_name && strcmp(hold->zone_name, "DefaultMallocZone") == 0) {
        malloc_set_zone_name(hold, NULL);
    }
    malloc_set_zone_name(zone, "DefaultMallocZone");

    unsigned protect_size = malloc_num_zones_allocated * sizeof(malloc_zone_t *);
    mprotect(malloc_zones, protect_size, PROT_READ | PROT_WRITE);

    // assert(zone == malloc_zones[malloc_num_zones - 1];
    for (i = malloc_num_zones - 1; i > 0; --i) {
        malloc_zones[i] = malloc_zones[i - 1];
    }
    malloc_zones[0] = zone;

    mprotect(malloc_zones, protect_size, PROT_READ);
    MALLOC_UNLOCK();
}

void
malloc_destroy_zone(malloc_zone_t *zone) {
    malloc_set_zone_name(zone, NULL); // Deallocate zone name wherever it may reside PR_7701095
    malloc_zone_unregister(zone);
    zone->destroy(zone);
}

/*********      Block creation and manipulation ************/

static void
internal_check(void) {
    static vm_address_t *frames = NULL;
    static unsigned     num_frames;
    if (malloc_zone_check(NULL)) {
                if (!frames) vm_allocate(mach_task_self(), (void *)&frames, vm_page_size, 1);
                thread_stack_pcs(frames, vm_page_size/sizeof(vm_address_t) - 1, &num_frames);
    } else {
        _SIMPLE_STRING b = _simple_salloc();
        if (b)
            _simple_sprintf(b, "*** MallocCheckHeap: FAILED check at %dth operation\n", malloc_check_counter-1);
        else
            _malloc_printf(MALLOC_PRINTF_NOLOG, "*** MallocCheckHeap: FAILED check at %dth operation\n", malloc_check_counter-1);
        malloc_printf("*** MallocCheckHeap: FAILED check at %dth operation\n", malloc_check_counter-1);
        if (frames) {
            unsigned    index = 1;
            if (b) {
                _simple_sappend(b, "Stack for last operation where the malloc check succeeded: ");
                while (index < num_frames) _simple_sprintf(b, "%p ", frames[index++]);
                malloc_printf("%s\n(Use 'atos' for a symbolic stack)\n", _simple_string(b));
            } else {
                /*
                 * Should only get here if vm_allocate() can't get a single page of
                 * memory, implying _simple_asl_log() would also fail.  So we just
                 * print to the file descriptor.
                 */
                _malloc_printf(MALLOC_PRINTF_NOLOG, "Stack for last operation where the malloc check succeeded: ");
                while (index < num_frames) _malloc_printf(MALLOC_PRINTF_NOLOG, "%p ", frames[index++]);
                _malloc_printf(MALLOC_PRINTF_NOLOG, "\n(Use 'atos' for a symbolic stack)\n");
            }
        }
        if (malloc_check_each > 1) {
            unsigned    recomm_each = (malloc_check_each > 10) ? malloc_check_each/10 : 1;
            unsigned    recomm_start = (malloc_check_counter > malloc_check_each+1) ? malloc_check_counter-1-malloc_check_each : 1;
            malloc_printf("*** Recommend using 'setenv MallocCheckHeapStart %d; setenv MallocCheckHeapEach %d' to narrow down failure\n", recomm_start, recomm_each);
        }
        if (malloc_check_abort) {
            CRSetCrashLogMessage(b ? _simple_string(b) : "*** MallocCheckHeap: FAILED check");
            abort();
        } else if (b)
            _simple_sfree(b);
        if (malloc_check_sleep > 0) {
            _malloc_printf(ASL_LEVEL_NOTICE, "*** Sleeping for %d seconds to leave time to attach\n",
                malloc_check_sleep);
            sleep(malloc_check_sleep);
        } else if (malloc_check_sleep < 0) {
            _malloc_printf(ASL_LEVEL_NOTICE, "*** Sleeping once for %d seconds to leave time to attach\n",
                -malloc_check_sleep);
            sleep(-malloc_check_sleep);
            malloc_check_sleep = 0;
        }
    }
    malloc_check_start += malloc_check_each;
}

void *
malloc_zone_malloc(malloc_zone_t *zone, size_t size) {
    void        *ptr;
    if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
        internal_check();
    }
    if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
        return NULL;
    }
    ptr = zone->malloc(zone, size);
    if (malloc_logger) 
        malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)size, 0, (uintptr_t)ptr, 0);
    return ptr;
}

void *
malloc_zone_calloc(malloc_zone_t *zone, size_t num_items, size_t size) {
    void        *ptr;
    if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
        internal_check();
    }
    if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
        return NULL;
    }
    ptr = zone->calloc(zone, num_items, size);
    if (malloc_logger)
        malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE | MALLOC_LOG_TYPE_CLEARED, (uintptr_t)zone, (uintptr_t)(num_items * size), 0, 
            (uintptr_t)ptr, 0);
    return ptr;
}

void *
malloc_zone_valloc(malloc_zone_t *zone, size_t size) {
    void        *ptr;
    if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
        internal_check();
    }
    if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
        return NULL;
    }
    ptr = zone->valloc(zone, size);
    if (malloc_logger)
        malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)size, 0, (uintptr_t)ptr, 0);
    return ptr;
}

void *
malloc_zone_realloc(malloc_zone_t *zone, void *ptr, size_t size) {
    void        *new_ptr;
    if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
        internal_check();
    }
    if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
        return NULL;
    }
    new_ptr = zone->realloc(zone, ptr, size);
    if (malloc_logger)
        malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_DEALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)ptr, (uintptr_t)size, 
            (uintptr_t)new_ptr, 0);
    return new_ptr;
}

void
malloc_zone_free(malloc_zone_t *zone, void *ptr) {
    if (malloc_logger)
        malloc_logger(MALLOC_LOG_TYPE_DEALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)ptr, 0, 0, 0);
    if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
        internal_check();
    }
    zone->free(zone, ptr);
}

static void
malloc_zone_free_definite_size(malloc_zone_t *zone, void *ptr, size_t size) {
    if (malloc_logger)
        malloc_logger(MALLOC_LOG_TYPE_DEALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)ptr, 0, 0, 0);
    if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
        internal_check();
    }
    zone->free_definite_size(zone, ptr, size);
}

malloc_zone_t *
malloc_zone_from_ptr(const void *ptr) {
    if (!ptr)
        return NULL;
    else
        return find_registered_zone(ptr, NULL);
}

void *
malloc_zone_memalign(malloc_zone_t *zone, size_t alignment, size_t size) {
    void        *ptr;
    if (zone->version < 5) // Version must be >= 5 to look at the new memalign field.
        return NULL;
    if (!(zone->memalign))
        return NULL;
    if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
        internal_check();
    }
    if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
        return NULL;
    }
    if (alignment < sizeof( void *) ||          // excludes 0 == alignment
        0 != (alignment & (alignment - 1))) {   // relies on sizeof(void *) being a power of two.
        return NULL;
    }
    ptr = zone->memalign(zone, alignment, size);
    if (malloc_logger)
        malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)size, 0, (uintptr_t)ptr, 0);
    return ptr;
}

/*********      Functions for zone implementors ************/

void
malloc_zone_register(malloc_zone_t *zone) {
    MALLOC_LOCK();
    malloc_zone_register_while_locked(zone);
    MALLOC_UNLOCK();
}

void
malloc_zone_unregister(malloc_zone_t *z) {
    unsigned    index;

    if (malloc_num_zones == 0)
        return;
  
    MALLOC_LOCK();
    for (index = 0; index < malloc_num_zones; ++index) {
        if (z != malloc_zones[index])
            continue;
      
        // Modify the page to be allow write access, so that we can update the
        // malloc_zones array.
        size_t protect_size = malloc_num_zones_allocated * sizeof(malloc_zone_t *);
        mprotect(malloc_zones, protect_size, PROT_READ | PROT_WRITE);

        // If we found a match, replace it with the entry at the end of the list, shrink the list,
        // and leave the end of the list intact to avoid racing with find_registered_zone().

        malloc_zones[index] = malloc_zones[malloc_num_zones - 1];
        --malloc_num_zones;
        
        mprotect(malloc_zones, protect_size, PROT_READ);
        
        // Exchange the roles of the FRZ counters. The counter that has captured the number of threads presently
        // executing *inside* find_regiatered_zone is swapped with the counter drained to zero last time through.
        // The former is then allowed to drain to zero while this thread yields.
        int *p = pFRZCounterLive;
        pFRZCounterLive = pFRZCounterDrain;
        pFRZCounterDrain = p;
        __sync_synchronize(); // Full memory barrier

        while (0 != *pFRZCounterDrain) { pthread_yield_np(); }
        
        MALLOC_UNLOCK();
        
        return;
    }
    MALLOC_UNLOCK();
    malloc_printf("*** malloc_zone_unregister() failed for %p\n", z);
}

void
malloc_set_zone_name(malloc_zone_t *z, const char *name) {
    char        *newName;
    
    mprotect(z, sizeof(malloc_zone_t), PROT_READ | PROT_WRITE);
    if (z->zone_name) {
        free((char *)z->zone_name);
        z->zone_name = NULL;
    }
    if (name) {
        size_t buflen = strlen(name) + 1;
        newName = malloc_zone_malloc(z, buflen);
        if (newName) {
            strlcpy(newName, name, buflen);
            z->zone_name = (const char *)newName;
        } else {
            z->zone_name = NULL;
        }
    }
    mprotect(z, sizeof(malloc_zone_t), PROT_READ);
}

const char *
malloc_get_zone_name(malloc_zone_t *zone) {
    return zone->zone_name;
}

/*
 * XXX malloc_printf now uses _simple_*printf.  It only deals with a
 * subset of printf format specifiers, but it doesn't call malloc.
 */

__private_extern__ void
_malloc_vprintf(int flags, const char *format, va_list ap)
{
    _SIMPLE_STRING b;

    if (_malloc_no_asl_log || (flags & MALLOC_PRINTF_NOLOG) || (b = _simple_salloc()) == NULL) {
        if (!(flags & MALLOC_PRINTF_NOPREFIX)) {
            if (__is_threaded) {
                /* XXX somewhat rude 'knowing' that pthread_t is a pointer */
                _simple_dprintf(malloc_debug_file, "%s(%d,%p) malloc: ", getprogname(), getpid(), (void *)pthread_self());
            } else {
                _simple_dprintf(malloc_debug_file, "%s(%d) malloc: ", getprogname(), getpid());
            }
        }
        _simple_vdprintf(malloc_debug_file, format, ap);
        return;
    }
    if (!(flags & MALLOC_PRINTF_NOPREFIX)) {
        if (__is_threaded) {
            /* XXX somewhat rude 'knowing' that pthread_t is a pointer */
            _simple_sprintf(b, "%s(%d,%p) malloc: ", getprogname(), getpid(), (void *)pthread_self());
        } else {
            _simple_sprintf(b, "%s(%d) malloc: ", getprogname(), getpid());
        }
    }
    _simple_vsprintf(b, format, ap);
    _simple_put(b, malloc_debug_file);
    _simple_asl_log(flags & MALLOC_PRINTF_LEVEL_MASK, Malloc_Facility, _simple_string(b));
    _simple_sfree(b);
}

__private_extern__ void
_malloc_printf(int flags, const char *format, ...)
{
    va_list ap;

    va_start(ap, format);
    _malloc_vprintf(flags, format, ap);
    va_end(ap);
}

void
malloc_printf(const char *format, ...)
{
    va_list ap;

    va_start(ap, format);
    _malloc_vprintf(ASL_LEVEL_ERR, format, ap);
    va_end(ap);
}

/*********      Generic ANSI callouts   ************/

void *
malloc(size_t size) {
    void        *retval;
    retval = malloc_zone_malloc(inline_malloc_default_zone(), size);
    if (retval == NULL) {
        errno = ENOMEM;
    }
    return retval;
}

void *
calloc(size_t num_items, size_t size) {
    void        *retval;
    retval = malloc_zone_calloc(inline_malloc_default_zone(), num_items, size);
    if (retval == NULL) {
        errno = ENOMEM;
    }
    return retval;
}

void
free(void *ptr) {
    malloc_zone_t       *zone;
    size_t              size;
    if (!ptr)
        return;
    zone = find_registered_zone(ptr, &size);
    if (!zone) {
        malloc_printf("*** error for object %p: pointer being freed was not allocated\n"
        "*** set a breakpoint in malloc_error_break to debug\n", ptr);
        malloc_error_break();
        if ((malloc_debug_flags & (SCALABLE_MALLOC_ABORT_ON_CORRUPTION|SCALABLE_MALLOC_ABORT_ON_ERROR))) {
            _SIMPLE_STRING b = _simple_salloc();
            if (b) {
                _simple_sprintf(b, "*** error for object %p: pointer being freed was not allocated\n", ptr);
                CRSetCrashLogMessage(_simple_string(b));
            } else {
                CRSetCrashLogMessage("*** error: pointer being freed was not allocated\n");
            }
            abort();
        }
    } else if (zone->version >= 6 && zone->free_definite_size)
        malloc_zone_free_definite_size(zone, ptr, size);
    else
        malloc_zone_free(zone, ptr);
}

void *
realloc(void *in_ptr, size_t new_size) {
    void                *retval = NULL;
    void                *old_ptr;
    malloc_zone_t       *zone;
    size_t              old_size = 0;

    // SUSv3: "If size is 0 and ptr is not a null pointer, the object
    // pointed to is freed. If the space cannot be allocated, the object
    // shall remain unchanged."  Also "If size is 0, either a null pointer
    // or a unique pointer that can be successfully passed to free() shall
    // be returned."  We choose to allocate a minimum size object by calling
    // malloc_zone_malloc with zero size, which matches "If ptr is a null
    // pointer, realloc() shall be equivalent to malloc() for the specified
    // size."  So we only free the original memory if the allocation succeeds.
    old_ptr = (new_size == 0) ? NULL : in_ptr;
    if (!old_ptr) {
        retval = malloc_zone_malloc(inline_malloc_default_zone(), new_size);
    } else {
        zone = find_registered_zone(old_ptr, &old_size);
        if (!zone) {
            malloc_printf("*** error for object %p: pointer being realloc'd was not allocated\n"
            "*** set a breakpoint in malloc_error_break to debug\n", old_ptr);
            malloc_error_break();
            if ((malloc_debug_flags & (SCALABLE_MALLOC_ABORT_ON_CORRUPTION|SCALABLE_MALLOC_ABORT_ON_ERROR))) {
                _SIMPLE_STRING b = _simple_salloc();
                if (b) {
                    _simple_sprintf(b, "*** error for object %p: pointer being realloc'd was not allocated\n", old_ptr);
                    CRSetCrashLogMessage(_simple_string(b));
                } else {
                    CRSetCrashLogMessage("*** error: pointer being realloc'd was not allocated\n");
                }
                abort();
            }
        } else {
            retval = malloc_zone_realloc(zone, old_ptr, new_size);
        }
    }
    if (retval == NULL) {
        errno = ENOMEM;
    } else if (new_size == 0) {
        free(in_ptr);
    }
    return retval;
}

void *
valloc(size_t size) {
    void        *retval;
    malloc_zone_t       *zone = inline_malloc_default_zone();
    retval = malloc_zone_valloc(zone, size);
    if (retval == NULL) {
        errno = ENOMEM;
    }
    return retval;
}

extern void
vfree(void *ptr) {
    free(ptr);
}

size_t
malloc_size(const void *ptr) {
    size_t      size = 0;
    
    if (!ptr) 
    return size;
        
    (void)find_registered_zone(ptr, &size);
    return size;
}

size_t
malloc_good_size (size_t size) {
    malloc_zone_t       *zone = inline_malloc_default_zone();
    return zone->introspect->good_size(zone, size);
}

/*
 * The posix_memalign() function shall allocate size bytes aligned on a boundary specified by alignment, 
 * and shall return a pointer to the allocated memory in memptr. 
 * The value of alignment shall be a multiple of sizeof( void *), that is also a power of two. 
 * Upon successful completion, the value pointed to by memptr shall be a multiple of alignment.
 *
 * Upon successful completion, posix_memalign() shall return zero; otherwise,
 * an error number shall be returned to indicate the error.
 *
 * The posix_memalign() function shall fail if:
 * EINVAL
 *      The value of the alignment parameter is not a power of two multiple of sizeof( void *).
 * ENOMEM
 *      There is insufficient memory available with the requested alignment.
 */
 
int 
posix_memalign(void **memptr, size_t alignment, size_t size)
{
    void        *retval;
    
    /* POSIX is silent on NULL == memptr !?! */

    retval = malloc_zone_memalign(inline_malloc_default_zone(), alignment, size);
    if (retval == NULL) {
        // To avoid testing the alignment constraints redundantly, we'll rely on the
        // test made in malloc_zone_memalign to vet each request. Only if that test fails
        // and returns NULL, do we arrive here to detect the bogus alignment and give the
        // required EINVAL return.
        if (alignment < sizeof( void *) ||              // excludes 0 == alignment 
            0 != (alignment & (alignment - 1))) {       // relies on sizeof(void *) being a power of two.
            return EINVAL;
        }
        return ENOMEM;
    } else {
        *memptr = retval; // Set iff allocation succeeded
        return 0;
    }
}

static malloc_zone_t *
find_registered_purgeable_zone(void *ptr) {
    if (!ptr)
        return NULL;
    
    /*
     * Look for a zone which contains ptr.  If that zone does not have the purgeable malloc flag
     * set, or the allocation is too small, do nothing.  Otherwise, set the allocation volatile.
     * FIXME: for performance reasons, we should probably keep a separate list of purgeable zones
     * and only search those.
     */
    size_t size = 0;
    malloc_zone_t *zone = find_registered_zone(ptr, &size);
    
    /* FIXME: would really like a zone->introspect->flags->purgeable check, but haven't determined
     * binary compatibility impact of changing the introspect struct yet. */
    if (!zone)
        return NULL;

    /* Check to make sure pointer is page aligned and size is multiple of page size */
    if ((size < vm_page_size) || ((size % vm_page_size) != 0))
        return NULL;

    return zone;
}

void
malloc_make_purgeable(void *ptr) {
    malloc_zone_t *zone = find_registered_purgeable_zone(ptr);
    if (!zone)
        return;
    
    int state = VM_PURGABLE_VOLATILE;
    vm_purgable_control(mach_task_self(), (vm_address_t)ptr, VM_PURGABLE_SET_STATE, &state);
    return;
}

/* Returns true if ptr is valid.  Ignore the return value from vm_purgeable_control and only report
 * state. */
int
malloc_make_nonpurgeable(void *ptr) {
    malloc_zone_t *zone = find_registered_purgeable_zone(ptr);
    if (!zone)
        return 0;

    int state = VM_PURGABLE_NONVOLATILE;
    vm_purgable_control(mach_task_self(), (vm_address_t)ptr, VM_PURGABLE_SET_STATE, &state);
    
    if (state == VM_PURGABLE_EMPTY)
        return EFAULT;

    return 0;
}

size_t malloc_zone_pressure_relief(malloc_zone_t *zone, size_t goal)
{
    if (!zone) {
        unsigned index = 0;
        size_t total = 0;

        // Take lock to defend against malloc_destroy_zone()
        MALLOC_LOCK();
        while (index < malloc_num_zones) {
            zone = malloc_zones[index++];
            if (zone->version < 8)
                continue;
            if (NULL == zone->pressure_relief)
                continue;
            if (0 == goal) /* Greedy */
                total += zone->pressure_relief(zone, 0);
            else if (goal > total)
                total += zone->pressure_relief(zone, goal - total);
            else /* total >= goal */
                break;
        }
        MALLOC_UNLOCK();
        return total;
    } else {
        // Assumes zone is not destroyed for the duration of this call
        if (zone->version < 8)
            return 0;
        if (NULL == zone->pressure_relief)
            return 0;
        return zone->pressure_relief(zone, goal);
    }
}

/*********      Batch methods   ************/

unsigned
malloc_zone_batch_malloc(malloc_zone_t *zone, size_t size, void **results, unsigned num_requested) {
    unsigned    (*batch_malloc)(malloc_zone_t *, size_t, void **, unsigned) = zone-> batch_malloc;
    if (! batch_malloc)
        return 0;
    if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
        internal_check();
    }
    unsigned    batched = batch_malloc(zone, size, results, num_requested);
    if (malloc_logger) {
        unsigned        index = 0;
        while (index < batched) {
            malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)size, 0, (uintptr_t)results[index], 0);
            index++;
        }
    }
    return batched;
}

void
malloc_zone_batch_free(malloc_zone_t *zone, void **to_be_freed, unsigned num) {
    if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
        internal_check();
    }
    if (malloc_logger) {
        unsigned        index = 0;
        while (index < num) {
            malloc_logger(MALLOC_LOG_TYPE_DEALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)to_be_freed[index], 0, 0, 0);
            index++;
        }
    }
    void        (*batch_free)(malloc_zone_t *, void **, unsigned) = zone-> batch_free;
    if (batch_free) {
        batch_free(zone, to_be_freed, num);
    } else {
        void    (*free_fun)(malloc_zone_t *, void *) = zone->free;
        while (num--) {
            void        *ptr = *to_be_freed++;
            free_fun(zone, ptr);
        }
    }
}

/*********      Functions for performance tools ************/

static kern_return_t
_malloc_default_reader(task_t task, vm_address_t address, vm_size_t size, void **ptr) {
    *ptr = (void *)address;
    return 0;
}

kern_return_t
malloc_get_all_zones(task_t task, memory_reader_t reader, vm_address_t **addresses, unsigned *count) {
    // Note that the 2 following addresses are not correct if the address of the target is different from your own.  This notably occurs if the address of System.framework is slid (e.g. different than at B & I )
    vm_address_t        remote_malloc_zones = (vm_address_t)&malloc_zones;
    vm_address_t        remote_malloc_num_zones = (vm_address_t)&malloc_num_zones;
    kern_return_t       err;
    vm_address_t        zones_address;
    vm_address_t        *zones_address_ref;
    unsigned            num_zones;
    unsigned            *num_zones_ref;
    if (!reader) reader = _malloc_default_reader;
    // printf("Read malloc_zones at address %p should be %p\n", &malloc_zones, malloc_zones);
    err = reader(task, remote_malloc_zones, sizeof(void *), (void **)&zones_address_ref);
    // printf("Read malloc_zones[%p]=%p\n", remote_malloc_zones, *zones_address_ref);
    if (err) {
        malloc_printf("*** malloc_get_all_zones: error reading zones_address at %p\n", (unsigned)remote_malloc_zones);
        return err;
    }
    zones_address = *zones_address_ref;
    // printf("Reading num_zones at address %p\n", remote_malloc_num_zones);
    err = reader(task, remote_malloc_num_zones, sizeof(unsigned), (void **)&num_zones_ref);
    if (err) {
        malloc_printf("*** malloc_get_all_zones: error reading num_zones at %p\n", (unsigned)remote_malloc_num_zones);
        return err;
    }
    num_zones = *num_zones_ref;
    // printf("Read malloc_num_zones[%p]=%d\n", remote_malloc_num_zones, num_zones);
    *count = num_zones;
    // printf("malloc_get_all_zones succesfully found %d zones\n", num_zones);
    err = reader(task, zones_address, sizeof(malloc_zone_t *) * num_zones, (void **)addresses);
    if (err) {
        malloc_printf("*** malloc_get_all_zones: error reading zones at %p\n", &zones_address);
        return err;
    }
    // printf("malloc_get_all_zones succesfully read %d zones\n", num_zones);
    return err;
}

/*********      Debug helpers   ************/

void
malloc_zone_print_ptr_info(void *ptr) {
    malloc_zone_t       *zone;
    if (!ptr) return;
    zone = malloc_zone_from_ptr(ptr);
    if (zone) {
        printf("ptr %p in registered zone %p\n", ptr, zone);
    } else {
        printf("ptr %p not in heap\n", ptr);
    }
}

boolean_t
malloc_zone_check(malloc_zone_t *zone) {
    boolean_t   ok = 1;
    if (!zone) {
        unsigned        index = 0;
        while (index < malloc_num_zones) {
            zone = malloc_zones[index++];
            if (!zone->introspect->check(zone)) ok = 0;
        }
    } else {
        ok = zone->introspect->check(zone);
    }
    return ok;
}

void
malloc_zone_print(malloc_zone_t *zone, boolean_t verbose) {
    if (!zone) {
        unsigned        index = 0;
        while (index < malloc_num_zones) {
            zone = malloc_zones[index++];
            zone->introspect->print(zone, verbose);
        }
    } else {
        zone->introspect->print(zone, verbose);
    }
}

void
malloc_zone_statistics(malloc_zone_t *zone, malloc_statistics_t *stats) {
    if (!zone) {
        memset(stats, 0, sizeof(*stats));
        unsigned        index = 0;
        while (index < malloc_num_zones) {
            zone = malloc_zones[index++];
            malloc_statistics_t this_stats;
            zone->introspect->statistics(zone, &this_stats);
            stats->blocks_in_use += this_stats.blocks_in_use;
            stats->size_in_use += this_stats.size_in_use;
            stats->max_size_in_use += this_stats.max_size_in_use;
            stats->size_allocated += this_stats.size_allocated;
        }
    } else {
        zone->introspect->statistics(zone, stats);
    }
}

void
malloc_zone_log(malloc_zone_t *zone, void *address) {
    if (!zone) {
        unsigned        index = 0;
        while (index < malloc_num_zones) {
            zone = malloc_zones[index++];
            zone->introspect->log(zone, address);
        }
    } else {
        zone->introspect->log(zone, address);
    }
}

/*********      Misc other entry points ************/

static void
DefaultMallocError(int x) {
#if USE_SLEEP_RATHER_THAN_ABORT
    malloc_printf("*** error %d\n", x);
    sleep(3600);
#else
    _SIMPLE_STRING b = _simple_salloc();
    if (b) {
        _simple_sprintf(b, "*** error %d", x);
        malloc_printf("%s\n", _simple_string(b));
        CRSetCrashLogMessage(_simple_string(b));
    } else {
        _malloc_printf(MALLOC_PRINTF_NOLOG, "*** error %d", x);
        CRSetCrashLogMessage("*** DefaultMallocError called");
    }
    abort();
#endif
}

void (*
malloc_error(void (*func)(int)))(int) {
    return DefaultMallocError;
}

/* Stack logging fork-handling prototypes */
extern void __stack_logging_fork_prepare();
extern void __stack_logging_fork_parent();
extern void __stack_logging_fork_child();
extern void __stack_logging_early_finished();

void
_malloc_fork_prepare() {
    /* Prepare the malloc module for a fork by insuring that no thread is in a malloc critical section */
    unsigned    index = 0;
    MALLOC_LOCK();
    while (index < malloc_num_zones) {
        malloc_zone_t   *zone = malloc_zones[index++];
        zone->introspect->force_lock(zone);
    }
        __stack_logging_fork_prepare();
}

void
_malloc_fork_parent() {
    /* Called in the parent process after a fork() to resume normal operation. */
    unsigned    index = 0;
        __stack_logging_fork_parent();
    MALLOC_UNLOCK();
    while (index < malloc_num_zones) {
        malloc_zone_t   *zone = malloc_zones[index++];
        zone->introspect->force_unlock(zone);
    }
}

void
_malloc_fork_child() {
    /* Called in the child process after a fork() to resume normal operation.  In the MTASK case we also have to change memory inheritance so that the child does not share memory with the parent. */
    unsigned    index = 0;
        __stack_logging_fork_child();
    MALLOC_UNLOCK();
    while (index < malloc_num_zones) {
        malloc_zone_t   *zone = malloc_zones[index++];
        zone->introspect->force_unlock(zone);
    }
}

/*
 * A Glibc-like mstats() interface.
 *
 * Note that this interface really isn't very good, as it doesn't understand
 * that we may have multiple allocators running at once.  We just massage
 * the result from malloc_zone_statistics in any case.
 */
struct mstats
mstats(void)
{
    malloc_statistics_t s;
    struct mstats m;

    malloc_zone_statistics(NULL, &s);
    m.bytes_total = s.size_allocated;
    m.chunks_used = s.blocks_in_use;
    m.bytes_used = s.size_in_use;
    m.chunks_free = 0;
    m.bytes_free = m.bytes_total - m.bytes_used;        /* isn't this somewhat obvious? */

    return(m);
}

boolean_t
malloc_zone_enable_discharge_checking(malloc_zone_t *zone)
{
    if (zone->version < 7) // Version must be >= 7 to look at the new discharge checking fields.
        return FALSE;
    if (NULL == zone->introspect->enable_discharge_checking)
        return FALSE;
    return zone->introspect->enable_discharge_checking(zone);
}

void
malloc_zone_disable_discharge_checking(malloc_zone_t *zone)
{
    if (zone->version < 7) // Version must be >= 7 to look at the new discharge checking fields.
        return;
    if (NULL == zone->introspect->disable_discharge_checking)
        return;
    zone->introspect->disable_discharge_checking(zone);
}

void
malloc_zone_discharge(malloc_zone_t *zone, void *memory)
{
    if (NULL == zone)
        zone = malloc_zone_from_ptr(memory);
    if (NULL == zone)
        return;
    if (zone->version < 7) // Version must be >= 7 to look at the new discharge checking fields.
        return;
    if (NULL == zone->introspect->discharge)
        return;
    zone->introspect->discharge(zone, memory);
}
 
void
malloc_zone_enumerate_discharged_pointers(malloc_zone_t *zone, void (^report_discharged)(void *memory, void *info))
{
    if (!zone) {
        unsigned        index = 0;
        while (index < malloc_num_zones) {
            zone = malloc_zones[index++];
            if (zone->version < 7)
                continue;
            if (NULL == zone->introspect->enumerate_discharged_pointers)
                continue;
            zone->introspect->enumerate_discharged_pointers(zone, report_discharged);
        }
    } else {
        if (zone->version < 7)
            return;
        if (NULL == zone->introspect->enumerate_discharged_pointers)
            return;
        zone->introspect->enumerate_discharged_pointers(zone, report_discharged);
    }
}

/*****************      OBSOLETE ENTRY POINTS   ********************/

#if PHASE_OUT_OLD_MALLOC
#error PHASE OUT THE FOLLOWING FUNCTIONS
#else
#warning PHASE OUT THE FOLLOWING FUNCTIONS
#endif

void
set_malloc_singlethreaded(boolean_t single) {
    static boolean_t warned = 0;
    if (!warned) {
#if PHASE_OUT_OLD_MALLOC
        malloc_printf("*** OBSOLETE: set_malloc_singlethreaded(%d)\n", single);
#endif
        warned = 1;
    }
}

void
malloc_singlethreaded() {
    static boolean_t warned = 0;
    if (!warned) {
        malloc_printf("*** OBSOLETE: malloc_singlethreaded()\n");
        warned = 1;
    }
}

int
malloc_debug(int level) {
    malloc_printf("*** OBSOLETE: malloc_debug()\n");
    return 0;
}