This is xnu-8019. See this file in:
/*
 * Copyright (c) 2010-2014 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

#include "_libkernel_init.h"
#include "strings.h"

extern _libkernel_functions_t _libkernel_functions;
extern void mig_os_release(void* ptr);

__attribute__((visibility("hidden")))
void *
malloc(size_t size)
{
	return _libkernel_functions->malloc(size);
}

__attribute__((visibility("hidden")))
void
free(void *ptr)
{
	return _libkernel_functions->free(ptr);
}

__attribute__((visibility("hidden")))
void *
realloc(void *ptr, size_t size)
{
	return _libkernel_functions->realloc(ptr, size);
}

__attribute__((visibility("hidden")))
void *
reallocf(void *ptr, size_t size)
{
	void *nptr = realloc(ptr, size);
	if (!nptr && ptr) {
		free(ptr);
	}
	return nptr;
}

__attribute__((visibility("hidden")))
void
_pthread_exit_if_canceled(int error)
{
	return _libkernel_functions->_pthread_exit_if_canceled(error);
}

__attribute__((visibility("hidden")))
void
_pthread_set_self(void *ptr __attribute__((__unused__)))
{
}

__attribute__((visibility("hidden")))
void
_pthread_clear_qos_tsd(mach_port_t thread_port)
{
	if (_libkernel_functions->version >= 3 &&
	    _libkernel_functions->pthread_clear_qos_tsd) {
		return _libkernel_functions->pthread_clear_qos_tsd(thread_port);
	}
}

__attribute__((visibility("hidden")))
int
pthread_current_stack_contains_np(const void *addr, size_t len)
{
	if (_libkernel_functions->version >= 4 &&
	    _libkernel_functions->pthread_current_stack_contains_np) {
		return _libkernel_functions->pthread_current_stack_contains_np(addr, len);
	}

	return 0;
}

/*
 * Upcalls to optimized libplatform string functions
 */

static const struct _libkernel_string_functions
    _libkernel_generic_string_functions = {
	.bzero = _libkernel_bzero,
	.memmove = _libkernel_memmove,
	.memset = _libkernel_memset,
	.strchr = _libkernel_strchr,
	.strcmp = _libkernel_strcmp,
	.strcpy = _libkernel_strcpy,
	.strlcpy = _libkernel_strlcpy,
	.strlen = _libkernel_strlen,
};
static _libkernel_string_functions_t _libkernel_string_functions =
    &_libkernel_generic_string_functions;

kern_return_t
__libkernel_platform_init(_libkernel_string_functions_t fns)
{
	_libkernel_string_functions = fns;
	return KERN_SUCCESS;
}

__attribute__((visibility("hidden")))
void
bzero(void *s, size_t n)
{
	return _libkernel_string_functions->bzero(s, n);
}

__attribute__((visibility("hidden")))
void
__bzero(void *s, size_t n)
{
	return _libkernel_string_functions->bzero(s, n);
}

__attribute__((visibility("hidden")))
void *
memchr(const void *s, int c, size_t n)
{
	return _libkernel_string_functions->memchr(s, c, n);
}

__attribute__((visibility("hidden")))
int
memcmp(const void *s1, const void *s2, size_t n)
{
	return _libkernel_string_functions->memcmp(s1, s2, n);
}

__attribute__((visibility("hidden")))
void *
memmove(void *dst, const void *src, size_t n)
{
	return _libkernel_string_functions->memmove(dst, src, n);
}

__attribute__((visibility("hidden")))
void *
memcpy(void *dst, const void *src, size_t n)
{
	return _libkernel_string_functions->memmove(dst, src, n);
}

__attribute__((visibility("hidden")))
void *
memccpy(void *__restrict dst, const void *__restrict src, int c, size_t n)
{
	return _libkernel_string_functions->memccpy(dst, src, c, n);
}

__attribute__((visibility("hidden")))
void *
memset(void *b, int c, size_t len)
{
	return _libkernel_string_functions->memset(b, c, len);
}

__attribute__((visibility("hidden")))
char *
strchr(const char *s, int c)
{
	return _libkernel_string_functions->strchr(s, c);
}

__attribute__((visibility("hidden")))
char *
index(const char *s, int c)
{
	return _libkernel_string_functions->strchr(s, c);
}

__attribute__((visibility("hidden")))
int
strcmp(const char *s1, const char *s2)
{
	return _libkernel_string_functions->strcmp(s1, s2);
}

__attribute__((visibility("hidden")))
char *
strcpy(char * restrict dst, const char * restrict src)
{
	return _libkernel_string_functions->strcpy(dst, src);
}

__attribute__((visibility("hidden")))
size_t
strlcat(char * restrict dst, const char * restrict src, size_t maxlen)
{
	return _libkernel_string_functions->strlcat(dst, src, maxlen);
}

__attribute__((visibility("hidden")))
size_t
strlcpy(char * restrict dst, const char * restrict src, size_t maxlen)
{
	return _libkernel_string_functions->strlcpy(dst, src, maxlen);
}

__attribute__((visibility("hidden")))
size_t
strlen(const char *str)
{
	return _libkernel_string_functions->strlen(str);
}

__attribute__((visibility("hidden")))
int
strncmp(const char *s1, const char *s2, size_t n)
{
	return _libkernel_string_functions->strncmp(s1, s2, n);
}

__attribute__((visibility("hidden")))
char *
strncpy(char * restrict dst, const char * restrict src, size_t maxlen)
{
	return _libkernel_string_functions->strncpy(dst, src, maxlen);
}

__attribute__((visibility("hidden")))
size_t
strnlen(const char *s, size_t maxlen)
{
	return _libkernel_string_functions->strnlen(s, maxlen);
}

__attribute__((visibility("hidden")))
char *
strstr(const char *s, const char *find)
{
	return _libkernel_string_functions->strstr(s, find);
}

/*
 * mach/mach.h voucher_mach_msg API
 */

static const struct _libkernel_voucher_functions
    _libkernel_voucher_functions_empty;
static _libkernel_voucher_functions_t _libkernel_voucher_functions =
    &_libkernel_voucher_functions_empty;

kern_return_t
__libkernel_voucher_init(_libkernel_voucher_functions_t fns)
{
	_libkernel_voucher_functions = fns;
	return KERN_SUCCESS;
}

boolean_t
voucher_mach_msg_set(mach_msg_header_t *msg)
{
	if (_libkernel_voucher_functions->voucher_mach_msg_set) {
		return _libkernel_voucher_functions->voucher_mach_msg_set(msg);
	}
	return 0;
}

void
voucher_mach_msg_clear(mach_msg_header_t *msg)
{
	if (_libkernel_voucher_functions->voucher_mach_msg_clear) {
		return _libkernel_voucher_functions->voucher_mach_msg_clear(msg);
	}
}

voucher_mach_msg_state_t
voucher_mach_msg_adopt(mach_msg_header_t *msg)
{
	if (_libkernel_voucher_functions->voucher_mach_msg_adopt) {
		return _libkernel_voucher_functions->voucher_mach_msg_adopt(msg);
	}
	return VOUCHER_MACH_MSG_STATE_UNCHANGED;
}

void
voucher_mach_msg_revert(voucher_mach_msg_state_t state)
{
	if (_libkernel_voucher_functions->voucher_mach_msg_revert) {
		return _libkernel_voucher_functions->voucher_mach_msg_revert(state);
	}
}