/*
 * Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (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 "e_os.h"

#include "internal/err.h"
#include <openssl/crypto.h>
#include <openssl/evp.h>
#include <openssl/trace.h>
#include "ssl_local.h"
#include "sslerr.h"
#include "internal/thread_once.h"

static int stopped;

static void ssl_library_stop(void);

static CRYPTO_ONCE ssl_base = CRYPTO_ONCE_STATIC_INIT;
static int ssl_base_inited = 0;
DEFINE_RUN_ONCE_STATIC(ossl_init_ssl_base)
{
#ifndef OPENSSL_NO_COMP
    OSSL_TRACE(INIT, "ossl_init_ssl_base: "
               "SSL_COMP_get_compression_methods()\n");
    /*
     * This will initialise the built-in compression algorithms. The value
     * returned is a STACK_OF(SSL_COMP), but that can be discarded safely
     */
    SSL_COMP_get_compression_methods();
#endif
    ssl_sort_cipher_list();
    OSSL_TRACE(INIT,"ossl_init_ssl_base: SSL_add_ssl_module()\n");
    /*
     * We ignore an error return here. Not much we can do - but not that bad
     * either. We can still safely continue.
     */
    OPENSSL_atexit(ssl_library_stop);
    ssl_base_inited = 1;
    return 1;
}

static CRYPTO_ONCE ssl_strings = CRYPTO_ONCE_STATIC_INIT;
static int ssl_strings_inited = 0;
DEFINE_RUN_ONCE_STATIC(ossl_init_load_ssl_strings)
{
    /*
     * OPENSSL_NO_AUTOERRINIT is provided here to prevent at compile time
     * pulling in all the error strings during static linking
     */
#if !defined(OPENSSL_NO_ERR) && !defined(OPENSSL_NO_AUTOERRINIT)
    OSSL_TRACE(INIT, "ossl_init_load_ssl_strings: err_load_SSL_strings_int()\n");
    err_load_SSL_strings_int();
    ssl_strings_inited = 1;
#endif
    return 1;
}

DEFINE_RUN_ONCE_STATIC_ALT(ossl_init_no_load_ssl_strings,
                           ossl_init_load_ssl_strings)
{
    /* Do nothing in this case */
    return 1;
}

static void ssl_library_stop(void)
{
    /* Might be explicitly called and also by atexit */
    if (stopped)
        return;
    stopped = 1;

    if (ssl_base_inited) {
#ifndef OPENSSL_NO_COMP
        OSSL_TRACE(INIT, "ssl_library_stop: "
                   "ssl_comp_free_compression_methods_int()\n");
        ssl_comp_free_compression_methods_int();
#endif
    }

    if (ssl_strings_inited) {
        OSSL_TRACE(INIT, "ssl_library_stop: err_free_strings_int()\n");
        /*
         * If both crypto and ssl error strings are inited we will end up
         * calling err_free_strings_int() twice - but that's ok. The second
         * time will be a no-op. It's easier to do that than to try and track
         * between the two libraries whether they have both been inited.
         */
        err_free_strings_int();
    }
}

/*
 * If this function is called with a non NULL settings value then it must be
 * called prior to any threads making calls to any OpenSSL functions,
 * i.e. passing a non-null settings value is assumed to be single-threaded.
 */
int OPENSSL_init_ssl(uint64_t opts, const OPENSSL_INIT_SETTINGS * settings)
{
    static int stoperrset = 0;

    if (stopped) {
        if (!stoperrset) {
            /*
             * We only ever set this once to avoid getting into an infinite
             * loop where the error system keeps trying to init and fails so
             * sets an error etc
             */
            stoperrset = 1;
            ERR_raise(ERR_LIB_SSL, ERR_R_INIT_FAIL);
        }
        return 0;
    }

    opts |= OPENSSL_INIT_ADD_ALL_CIPHERS
         |  OPENSSL_INIT_ADD_ALL_DIGESTS;
#ifndef OPENSSL_NO_AUTOLOAD_CONFIG
    if ((opts & OPENSSL_INIT_NO_LOAD_CONFIG) == 0)
        opts |= OPENSSL_INIT_LOAD_CONFIG;
#endif

    if (!OPENSSL_init_crypto(opts, settings))
        return 0;

    if (!RUN_ONCE(&ssl_base, ossl_init_ssl_base))
        return 0;

    if ((opts & OPENSSL_INIT_NO_LOAD_SSL_STRINGS)
        && !RUN_ONCE_ALT(&ssl_strings, ossl_init_no_load_ssl_strings,
                         ossl_init_load_ssl_strings))
        return 0;

    if ((opts & OPENSSL_INIT_LOAD_SSL_STRINGS)
        && !RUN_ONCE(&ssl_strings, ossl_init_load_ssl_strings))
        return 0;

    return 1;
}