/*

 * Copyright 2013-2017 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

 */

/*

 * A minimal program to serve an SSL connection. It uses blocking. It uses

 * the SSL_CONF API with a configuration file. cc -I../../include saccept.c

 * -L../.. -lssl -lcrypto -ldl

 */

#include <stdio.h>

#include <string.h>

#include <signal.h>

#include <stdlib.h>

#include <openssl/err.h>

#include <openssl/ssl.h>

#include <openssl/conf.h>

int main(int argc, char *argv[])

{

    char *port = "*:4433";

    BIO *in = NULL;

    BIO *ssl_bio, *tmp;

    SSL_CTX *ctx;

    SSL_CONF_CTX *cctx = NULL;

    CONF *conf = NULL;

    STACK_OF(CONF_VALUE) *sect = NULL;

    CONF_VALUE *cnf;

    long errline = -1;

    char buf[512];

    int ret = EXIT_FAILURE, i;

    ctx = SSL_CTX_new(TLS_server_method());

    conf = NCONF_new(NULL);

    if (NCONF_load(conf, "accept.cnf", &errline) <= 0) {

        if (errline <= 0)

            fprintf(stderr, "Error processing config file\n");

        else

            fprintf(stderr, "Error on line %ld\n", errline);

        goto err;

    }

    sect = NCONF_get_section(conf, "default");

    if (sect == NULL) {

        fprintf(stderr, "Error retrieving default section\n");

        goto err;

    }

    cctx = SSL_CONF_CTX_new();

    SSL_CONF_CTX_set_flags(cctx, SSL_CONF_FLAG_SERVER);

    SSL_CONF_CTX_set_flags(cctx, SSL_CONF_FLAG_CERTIFICATE);

    SSL_CONF_CTX_set_flags(cctx, SSL_CONF_FLAG_FILE);

    SSL_CONF_CTX_set_ssl_ctx(cctx, ctx);

    for (i = 0; i < sk_CONF_VALUE_num(sect); i++) {

        int rv;

        cnf = sk_CONF_VALUE_value(sect, i);

        rv = SSL_CONF_cmd(cctx, cnf->name, cnf->value);

        if (rv > 0)

            continue;

        if (rv != -2) {

            fprintf(stderr, "Error processing %s = %s\n",

                    cnf->name, cnf->value);

            ERR_print_errors_fp(stderr);

            goto err;

        }

        if (strcmp(cnf->name, "Port") == 0) {

            port = cnf->value;

        } else {

            fprintf(stderr, "Unknown configuration option %s\n", cnf->name);

            goto err;

        }

    }

    if (!SSL_CONF_CTX_finish(cctx)) {

        fprintf(stderr, "Finish error\n");

        ERR_print_errors_fp(stderr);

        goto err;

    }

    /* Setup server side SSL bio */

    ssl_bio = BIO_new_ssl(ctx, 0);

    if ((in = BIO_new_accept(port)) == NULL)

        goto err;

    /*

     * This means that when a new connection is accepted on 'in', The ssl_bio

     * will be 'duplicated' and have the new socket BIO push into it.

     * Basically it means the SSL BIO will be automatically setup

     */

    BIO_set_accept_bios(in, ssl_bio);

 again:

    /*

     * The first call will setup the accept socket, and the second will get a

     * socket.  In this loop, the first actual accept will occur in the

     * BIO_read() function.

     */

    if (BIO_do_accept(in) <= 0)

        goto err;

    for (;;) {

        i = BIO_read(in, buf, 512);

        if (i == 0) {

            /*

             * If we have finished, remove the underlying BIO stack so the

             * next time we call any function for this BIO, it will attempt

             * to do an accept

             */

            printf("Done\n");

            tmp = BIO_pop(in);

            BIO_free_all(tmp);

            goto again;

        }

        if (i < 0) {

            if (BIO_should_retry(in))

                continue;

            goto err;

        }

        fwrite(buf, 1, i, stdout);

        fflush(stdout);

    }

    ret = EXIT_SUCCESS;

 err:

    if (ret != EXIT_SUCCESS)

        ERR_print_errors_fp(stderr);

    BIO_free(in);

    return ret;

}