/*
 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <openssl/crypto.h>
#include "internal/cryptlib.h"

/*
 * the following pointers may be changed as long as 'allow_customize' is set
 */
static int allow_customize = 1;

static void *(*malloc_impl)(size_t, const char *, int)
    = CRYPTO_malloc;
static void *(*realloc_impl)(void *, size_t, const char *, int)
    = CRYPTO_realloc;
static void (*free_impl)(void *, const char *, int)
    = CRYPTO_free;

#ifndef OPENSSL_NO_CRYPTO_MDEBUG
static int call_malloc_debug = 1;
#else
static int call_malloc_debug = 0;
#endif

int CRYPTO_set_mem_functions(
        void *(*m)(size_t, const char *, int),
        void *(*r)(void *, size_t, const char *, int),
        void (*f)(void *, const char *, int))
{
    if (!allow_customize)
        return 0;
    if (m)
        malloc_impl = m;
    if (r)
        realloc_impl = r;
    if (f)
        free_impl = f;
    return 1;
}

int CRYPTO_set_mem_debug(int flag)
{
    if (!allow_customize)
        return 0;
    call_malloc_debug = flag;
    return 1;
}

void CRYPTO_get_mem_functions(
        void *(**m)(size_t, const char *, int),
        void *(**r)(void *, size_t, const char *, int),
        void (**f)(void *, const char *, int))
{
    if (m != NULL)
        *m = malloc_impl;
    if (r != NULL)
        *r = realloc_impl;
    if (f != NULL)
        *f = free_impl;
}

void *CRYPTO_malloc(size_t num, const char *file, int line)
{
    void *ret = NULL;

    if (malloc_impl != NULL && malloc_impl != CRYPTO_malloc)
        return malloc_impl(num, file, line);

    if (num == 0)
        return NULL;

    if (allow_customize) {
        /*
         * Disallow customization after the first allocation. We only set this
         * if necessary to avoid a store to the same cache line on every
         * allocation.
         */
        allow_customize = 0;
    }
#ifndef OPENSSL_NO_CRYPTO_MDEBUG
    if (call_malloc_debug) {
        CRYPTO_mem_debug_malloc(NULL, num, 0, file, line);
        ret = malloc(num);
        CRYPTO_mem_debug_malloc(ret, num, 1, file, line);
    } else {
        ret = malloc(num);
    }
#else
    osslargused(file); osslargused(line);
    ret = malloc(num);
#endif

    return ret;
}

void *CRYPTO_zalloc(size_t num, const char *file, int line)
{
    void *ret = CRYPTO_malloc(num, file, line);

    if (ret != NULL)
        memset(ret, 0, num);
    return ret;
}

void *CRYPTO_realloc(void *str, size_t num, const char *file, int line)
{
    if (realloc_impl != NULL && realloc_impl != &CRYPTO_realloc)
        return realloc_impl(str, num, file, line);

    if (str == NULL)
        return CRYPTO_malloc(num, file, line);

    if (num == 0) {
        CRYPTO_free(str, file, line);
        return NULL;
    }

#ifndef OPENSSL_NO_CRYPTO_MDEBUG
    if (call_malloc_debug) {
        void *ret;
        CRYPTO_mem_debug_realloc(str, NULL, num, 0, file, line);
        ret = realloc(str, num);
        CRYPTO_mem_debug_realloc(str, ret, num, 1, file, line);
        return ret;
    }
#else
    osslargused(file); osslargused(line);
#endif
    return realloc(str, num);

}

void *CRYPTO_clear_realloc(void *str, size_t old_len, size_t num,
                           const char *file, int line)
{
    void *ret = NULL;

    if (str == NULL)
        return CRYPTO_malloc(num, file, line);

    if (num == 0) {
        CRYPTO_clear_free(str, old_len, file, line);
        return NULL;
    }

    /* Can't shrink the buffer since memcpy below copies |old_len| bytes. */
    if (num < old_len) {
        OPENSSL_cleanse((char*)str + num, old_len - num);
        return str;
    }

    ret = CRYPTO_malloc(num, file, line);
    if (ret != NULL) {
        memcpy(ret, str, old_len);
        CRYPTO_clear_free(str, old_len, file, line);
    }
    return ret;
}

void CRYPTO_free(void *str, const char *file, int line)
{
    if (free_impl != NULL && free_impl != &CRYPTO_free) {
        free_impl(str, file, line);
        return;
    }

#ifndef OPENSSL_NO_CRYPTO_MDEBUG
    if (call_malloc_debug) {
        CRYPTO_mem_debug_free(str, 0, file, line);
        free(str);
        CRYPTO_mem_debug_free(str, 1, file, line);
    } else {
        free(str);
    }
#else
    free(str);
#endif
}

void CRYPTO_clear_free(void *str, size_t num, const char *file, int line)
{
    if (str == NULL)
        return;
    if (num)
        OPENSSL_cleanse(str, num);
    CRYPTO_free(str, file, line);
}