text: /*
   * Copyright 1998-2016 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.
   * saccept host:port
   * host is the interface IP to use.  If any interface, use *:port
   * The default it *:4433
   *
   * cc -I../../include saccept.c -L../.. -lssl -lcrypto -ldl
   */
  
  #include <stdio.h>
  #include <signal.h>
  #include <openssl/err.h>
  #include <openssl/ssl.h>
  
  #define CERT_FILE       "server.pem"
  
  static int done = 0;
  
  void interrupt(int sig)
  {
      done = 1;
  }
  
  void sigsetup(void)
  {
      struct sigaction sa;
  
      /*
       * Catch at most once, and don't restart the accept system call.
       */
      sa.sa_flags = SA_RESETHAND;
      sa.sa_handler = interrupt;
      sigemptyset(&sa.sa_mask);
      sigaction(SIGINT, &sa, NULL);
  }
  
  int main(int argc, char *argv[])
  {
      char *port = NULL;
      BIO *in = NULL;
      BIO *ssl_bio, *tmp;
      SSL_CTX *ctx;
      char buf[512];
      int ret = 1, i;
  
      if (argc <= 1)
          port = "*:4433";
      else
          port = argv[1];
  
      ctx = SSL_CTX_new(TLS_server_method());
      if (!SSL_CTX_use_certificate_chain_file(ctx, CERT_FILE))
          goto err;
      if (!SSL_CTX_use_PrivateKey_file(ctx, CERT_FILE, SSL_FILETYPE_PEM))
          goto err;
      if (!SSL_CTX_check_private_key(ctx))
          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);
  
      /* Arrange to leave server loop on interrupt */
      sigsetup();
  
   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;
  
      while (!done) {
          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)
              goto err;
          fwrite(buf, 1, i, stdout);
          fflush(stdout);
      }
  
      ret = 0;
   err:
      if (ret) {
          ERR_print_errors_fp(stderr);
      }
      BIO_free(in);
      exit(ret);
      return (!ret);
  }
  