ssluse.c

        }
      }
      else /* not a UTF8 name */
        j = ASN1_STRING_to_UTF8(&peer_CN, tmp);
    }

    if (peer_CN == nulstr)
       peer_CN = NULL;
#ifdef CURL_DOES_CONVERSIONS
    else {
      /* convert peer_CN from UTF8 */
      size_t rc;
      rc = Curl_convert_from_utf8(data, peer_CN, strlen(peer_CN));
      /* Curl_convert_from_utf8 calls failf if unsuccessful */
      if (rc != CURLE_OK) {
        return(rc);
      }
    }
#endif /* CURL_DOES_CONVERSIONS */

    if (!peer_CN) {
      if(data->set.ssl.verifyhost > 1) {
        failf(data,
              "SSL: unable to obtain common name from peer certificate");
        return CURLE_SSL_PEER_CERTIFICATE;
      }
      else {
        /* Consider verifyhost == 1 as an "OK" for a missing CN field, but we
           output a note about the situation */
        infof(data, "\t common name: WARNING couldn't obtain\n");
      }
    }
    else if(!cert_hostcheck((const char *)peer_CN, conn->host.name)) {
      if(data->set.ssl.verifyhost > 1) {
        failf(data, "SSL: certificate subject name '%s' does not match "
              "target host name '%s'", peer_CN, conn->host.dispname);
        res = CURLE_SSL_PEER_CERTIFICATE;
      }
      else
        infof(data, "\t common name: %s (does not match '%s')\n",
              peer_CN, conn->host.dispname);
    }
    else {
      infof(data, "\t common name: %s (matched)\n", peer_CN);
    }
    if(peer_CN)
      OPENSSL_free(peer_CN);
  }
  return res;
}
#endif

/* The SSL_CTRL_SET_MSG_CALLBACK doesn't exist in ancient OpenSSL versions
   and thus this cannot be done there. */
#ifdef SSL_CTRL_SET_MSG_CALLBACK

static const char *ssl_msg_type(int ssl_ver, int msg)
{
  if (ssl_ver == SSL2_VERSION_MAJOR) {
    switch (msg) {
      case SSL2_MT_ERROR:
        return "Error";
      case SSL2_MT_CLIENT_HELLO:
        return "Client hello";
      case SSL2_MT_CLIENT_MASTER_KEY:
        return "Client key";
      case SSL2_MT_CLIENT_FINISHED:
        return "Client finished";
      case SSL2_MT_SERVER_HELLO:
        return "Server hello";
      case SSL2_MT_SERVER_VERIFY:
        return "Server verify";
      case SSL2_MT_SERVER_FINISHED:
        return "Server finished";
      case SSL2_MT_REQUEST_CERTIFICATE:
        return "Request CERT";
      case SSL2_MT_CLIENT_CERTIFICATE:
        return "Client CERT";
    }
  }
  else if (ssl_ver == SSL3_VERSION_MAJOR) {
    switch (msg) {
      case SSL3_MT_HELLO_REQUEST:
        return "Hello request";
      case SSL3_MT_CLIENT_HELLO:
        return "Client hello";
      case SSL3_MT_SERVER_HELLO:
        return "Server hello";
      case SSL3_MT_CERTIFICATE:
        return "CERT";
      case SSL3_MT_SERVER_KEY_EXCHANGE:
        return "Server key exchange";
      case SSL3_MT_CLIENT_KEY_EXCHANGE:
        return "Client key exchange";
      case SSL3_MT_CERTIFICATE_REQUEST:
        return "Request CERT";
      case SSL3_MT_SERVER_DONE:
        return "Server finished";
      case SSL3_MT_CERTIFICATE_VERIFY:
        return "CERT verify";
      case SSL3_MT_FINISHED:
        return "Finished";
    }
  }
  return "Unknown";
}

static const char *tls_rt_type(int type)
{
  return (
    type == SSL3_RT_CHANGE_CIPHER_SPEC ? "TLS change cipher, " :
    type == SSL3_RT_ALERT              ? "TLS alert, "         :
    type == SSL3_RT_HANDSHAKE          ? "TLS handshake, "     :
    type == SSL3_RT_APPLICATION_DATA   ? "TLS app data, "      :
                                         "TLS Unknown, ");
}


/*
 * Our callback from the SSL/TLS layers.
 */
static void ssl_tls_trace(int direction, int ssl_ver, int content_type,
                          const void *buf, size_t len, const SSL *ssl,
                          struct connectdata *conn)
{
  struct SessionHandle *data;
  const char *msg_name, *tls_rt_name;
  char ssl_buf[1024];
  int  ver, msg_type, txt_len;

  if (!conn || !conn->data || !conn->data->set.fdebug ||
      (direction != 0 && direction != 1))
    return;

  data = conn->data;
  ssl_ver >>= 8;
  ver = (ssl_ver == SSL2_VERSION_MAJOR ? '2' :
         ssl_ver == SSL3_VERSION_MAJOR ? '3' : '?');

  /* SSLv2 doesn't seem to have TLS record-type headers, so OpenSSL
   * always pass-up content-type as 0. But the interesting message-type
   * is at 'buf[0]'.
   */
  if (ssl_ver == SSL3_VERSION_MAJOR && content_type != 0)
    tls_rt_name = tls_rt_type(content_type);
  else
    tls_rt_name = "";

  msg_type = *(char*)buf;
  msg_name = ssl_msg_type(ssl_ver, msg_type);

  txt_len = snprintf(ssl_buf, sizeof(ssl_buf), "SSLv%c, %s%s (%d):\n",
                     ver, tls_rt_name, msg_name, msg_type);
  Curl_debug(data, CURLINFO_TEXT, ssl_buf, (size_t)txt_len, NULL);

  Curl_debug(data, (direction == 1) ? CURLINFO_SSL_DATA_OUT :
             CURLINFO_SSL_DATA_IN, (char *)buf, len, NULL);
  (void) ssl;
}
#endif

#ifdef USE_SSLEAY
/* ====================================================== */

static CURLcode
Curl_ossl_connect_step1(struct connectdata *conn,
                        int sockindex)
{
  CURLcode retcode = CURLE_OK;

  struct SessionHandle *data = conn->data;
  SSL_METHOD_QUAL SSL_METHOD *req_method=NULL;
  void *ssl_sessionid=NULL;
  curl_socket_t sockfd = conn->sock[sockindex];
  struct ssl_connect_data *connssl = &conn->ssl[sockindex];

  curlassert(ssl_connect_1 == connssl->connecting_state);

  /* Make funny stuff to get random input */
  Curl_ossl_seed(data);

  /* check to see if we've been told to use an explicit SSL/TLS version */
  switch(data->set.ssl.version) {
  default:
  case CURL_SSLVERSION_DEFAULT:
    /* we try to figure out version */
    req_method = SSLv23_client_method();
    break;
  case CURL_SSLVERSION_TLSv1:
    req_method = TLSv1_client_method();
    break;
  case CURL_SSLVERSION_SSLv2:
    req_method = SSLv2_client_method();
    break;
  case CURL_SSLVERSION_SSLv3:
    req_method = SSLv3_client_method();
    break;
  }

  if (connssl->ctx)
    SSL_CTX_free(connssl->ctx);
  connssl->ctx = SSL_CTX_new(req_method);

  if(!connssl->ctx) {
    failf(data, "SSL: couldn't create a context!");
    return CURLE_OUT_OF_MEMORY;
  }

#ifdef SSL_CTRL_SET_MSG_CALLBACK
  if (data->set.fdebug) {
    /* the SSL trace callback is only used for verbose logging so we only
       inform about failures of setting it */
    if (!SSL_CTX_callback_ctrl(connssl->ctx, SSL_CTRL_SET_MSG_CALLBACK,
                               (void (*)(void))ssl_tls_trace)) {
      infof(data, "SSL: couldn't set callback!\n");
    }
    else if (!SSL_CTX_ctrl(connssl->ctx, SSL_CTRL_SET_MSG_CALLBACK_ARG, 0,
                           conn)) {
      infof(data, "SSL: couldn't set callback argument!\n");
    }
  }
#endif

  /* OpenSSL contains code to work-around lots of bugs and flaws in various
     SSL-implementations. SSL_CTX_set_options() is used to enabled those
     work-arounds. The man page for this option states that SSL_OP_ALL enables
     all the work-arounds and that "It is usually safe to use SSL_OP_ALL to
     enable the bug workaround options if compatibility with somewhat broken
     implementations is desired."

  */
  SSL_CTX_set_options(connssl->ctx, SSL_OP_ALL);

#if 0
  /*
   * Not sure it's needed to tell SSL_connect() that socket is
   * non-blocking. It doesn't seem to care, but just return with
   * SSL_ERROR_WANT_x.
   */
  if (data->state.used_interface == Curl_if_multi)
    SSL_CTX_ctrl(connssl->ctx, BIO_C_SET_NBIO, 1, NULL);
#endif

  if(data->set.cert) {
    if(!cert_stuff(conn,
                   connssl->ctx,
                   data->set.cert,
                   data->set.cert_type,
                   data->set.key,
                   data->set.key_type)) {
      /* failf() is already done in cert_stuff() */
      return CURLE_SSL_CERTPROBLEM;
    }
  }

  if(data->set.ssl.cipher_list) {
    if(!SSL_CTX_set_cipher_list(connssl->ctx,
                                data->set.ssl.cipher_list)) {
      failf(data, "failed setting cipher list");
      return CURLE_SSL_CIPHER;
    }
  }

  if (data->set.ssl.CAfile || data->set.ssl.CApath) {
    /* tell SSL where to find CA certificates that are used to verify
       the servers certificate. */
    if (!SSL_CTX_load_verify_locations(connssl->ctx, data->set.ssl.CAfile,
                                       data->set.ssl.CApath)) {
      if (data->set.ssl.verifypeer) {
        /* Fail if we insist on successfully verifying the server. */
        failf(data,"error setting certificate verify locations:\n"
              "  CAfile: %s\n  CApath: %s\n",
              data->set.ssl.CAfile ? data->set.ssl.CAfile : "none",
              data->set.ssl.CApath ? data->set.ssl.CApath : "none");
        return CURLE_SSL_CACERT;
      }
      else {
        /* Just continue with a warning if no strict  certificate verification
           is required. */
        infof(data, "error setting certificate verify locations,"
              " continuing anyway:\n");
      }
    }
    else {
      /* Everything is fine. */
      infof(data, "successfully set certificate verify locations:\n");
    }
    infof(data,
          "  CAfile: %s\n"
          "  CApath: %s\n",
          data->set.ssl.CAfile ? data->set.ssl.CAfile : "none",
          data->set.ssl.CApath ? data->set.ssl.CApath : "none");
  }
  /* SSL always tries to verify the peer, this only says whether it should
   * fail to connect if the verification fails, or if it should continue
   * anyway. In the latter case the result of the verification is checked with
   * SSL_get_verify_result() below. */
  SSL_CTX_set_verify(connssl->ctx,
                     data->set.ssl.verifypeer?SSL_VERIFY_PEER:SSL_VERIFY_NONE,
                     cert_verify_callback);

  /* give application a chance to interfere with SSL set up. */
  if(data->set.ssl.fsslctx) {
    retcode = (*data->set.ssl.fsslctx)(data, connssl->ctx,
                                       data->set.ssl.fsslctxp);
    if(retcode) {
      failf(data,"error signaled by ssl ctx callback");
      return retcode;
    }
  }

  /* Lets make an SSL structure */
  if (connssl->handle)
    SSL_free(connssl->handle);
  connssl->handle = SSL_new(connssl->ctx);
  if (!connssl->handle) {
    failf(data, "SSL: couldn't create a context (handle)!");
    return CURLE_OUT_OF_MEMORY;
  }
  SSL_set_connect_state(connssl->handle);

  connssl->server_cert = 0x0;

  /* Check if there's a cached ID we can/should use here! */
  if(!Curl_ssl_getsessionid(conn, &ssl_sessionid, NULL)) {
    /* we got a session id, use it! */
    if (!SSL_set_session(connssl->handle, ssl_sessionid)) {
      failf(data, "SSL: SSL_set_session failed: %s",
            ERR_error_string(ERR_get_error(),NULL));
      return CURLE_SSL_CONNECT_ERROR;
    }
    /* Informational message */
    infof (data, "SSL re-using session ID\n");
  }

  /* pass the raw socket into the SSL layers */
  if (!SSL_set_fd(connssl->handle, sockfd)) {
     failf(data, "SSL: SSL_set_fd failed: %s",
           ERR_error_string(ERR_get_error(),NULL));
     return CURLE_SSL_CONNECT_ERROR;
  }

  connssl->connecting_state = ssl_connect_2;
  return CURLE_OK;
}

static CURLcode
Curl_ossl_connect_step2(struct connectdata *conn,
                        int sockindex, long *timeout_ms)
{
  struct SessionHandle *data = conn->data;
  int err;
  long has_passed;
  struct ssl_connect_data *connssl = &conn->ssl[sockindex];

  curlassert(ssl_connect_2 == connssl->connecting_state
             || ssl_connect_2_reading == connssl->connecting_state
             || ssl_connect_2_writing == connssl->connecting_state);

  /* Find out if any timeout is set. If not, use 300 seconds.
     Otherwise, figure out the most strict timeout of the two possible one
     and then how much time that has elapsed to know how much time we
     allow for the connect call */
  if(data->set.timeout && data->set.connecttimeout) {
    /* get the most strict timeout of the ones converted to milliseconds */
    if(data->set.timeout<data->set.connecttimeout)
      *timeout_ms = data->set.timeout*1000;
    else
      *timeout_ms = data->set.connecttimeout*1000;
  }
  else if(data->set.timeout)
    *timeout_ms = data->set.timeout*1000;
  else if(data->set.connecttimeout)
    *timeout_ms = data->set.connecttimeout*1000;
  else
    /* no particular time-out has been set */
    *timeout_ms= DEFAULT_CONNECT_TIMEOUT;

  /* Evaluate in milliseconds how much time that has passed */
  has_passed = Curl_tvdiff(Curl_tvnow(), data->progress.t_startsingle);

  /* subtract the passed time */
  *timeout_ms -= has_passed;

  if(*timeout_ms < 0) {
    /* a precaution, no need to continue if time already is up */
    failf(data, "SSL connection timeout");
    return CURLE_OPERATION_TIMEOUTED;
  }

  err = SSL_connect(connssl->handle);

  /* 1  is fine
     0  is "not successful but was shut down controlled"
     <0 is "handshake was not successful, because a fatal error occurred" */
  if(1 != err) {
    int detail = SSL_get_error(connssl->handle, err);

    if(SSL_ERROR_WANT_READ == detail) {
      connssl->connecting_state = ssl_connect_2_reading;
      return CURLE_OK;
    }
    else if(SSL_ERROR_WANT_WRITE == detail) {
      connssl->connecting_state = ssl_connect_2_writing;
      return CURLE_OK;
    }
    else {
      /* untreated error */
      unsigned long errdetail;
      char error_buffer[256]; /* OpenSSL documents that this must be at least
                                 256 bytes long. */
      CURLcode rc;
      const char *cert_problem = NULL;

      connssl->connecting_state = ssl_connect_2; /* the connection failed,
                                                    we're not waiting for
                                                    anything else. */

      errdetail = ERR_get_error(); /* Gets the earliest error code from the
                                      thread's error queue and removes the
                                      entry. */

      switch(errdetail) {
      case 0x1407E086:
        /* 1407E086:
           SSL routines:
           SSL2_SET_CERTIFICATE:
           certificate verify failed */
        /* fall-through */
      case 0x14090086:
        /* 14090086:
           SSL routines:
           SSL3_GET_SERVER_CERTIFICATE:
           certificate verify failed */
        cert_problem = "SSL certificate problem, verify that the CA cert is"
          " OK. Details:\n";
        rc = CURLE_SSL_CACERT;
        break;
      default:
        rc = CURLE_SSL_CONNECT_ERROR;
        break;
      }

      /* detail is already set to the SSL error above */

      /* If we e.g. use SSLv2 request-method and the server doesn't like us
       * (RST connection etc.), OpenSSL gives no explanation whatsoever and
       * the SO_ERROR is also lost.
       */
      if (CURLE_SSL_CONNECT_ERROR == rc && errdetail == 0) {
        failf(data, "Unknown SSL protocol error in connection to %s:%d ",
              conn->host.name, conn->port);
        return rc;
      }
      /* Could be a CERT problem */

      SSL_strerror(errdetail, error_buffer, sizeof(error_buffer));
      failf(data, "%s%s", cert_problem ? cert_problem : "", error_buffer);
      return rc;
    }
  }
  else {
    /* we have been connected fine, we're not waiting for anything else. */
    connssl->connecting_state = ssl_connect_3;

    /* Informational message */
    infof (data, "SSL connection using %s\n",
           SSL_get_cipher(connssl->handle));

    return CURLE_OK;
  }
}

static CURLcode
Curl_ossl_connect_step3(struct connectdata *conn,
                  int sockindex)
{
  CURLcode retcode = CURLE_OK;
  char * str;
  long lerr;
  ASN1_TIME *certdate;
  void *ssl_sessionid=NULL;
  struct SessionHandle *data = conn->data;
  struct ssl_connect_data *connssl = &conn->ssl[sockindex];

  curlassert(ssl_connect_3 == connssl->connecting_state);

  if(Curl_ssl_getsessionid(conn, &ssl_sessionid, NULL)) {
    /* Since this is not a cached session ID, then we want to stach this one
       in the cache! */
    SSL_SESSION *our_ssl_sessionid;
#ifdef HAVE_SSL_GET1_SESSION
    our_ssl_sessionid = SSL_get1_session(connssl->handle);

    /* SSL_get1_session() will increment the reference
       count and the session will stay in memory until explicitly freed with
       SSL_SESSION_free(3), regardless of its state.
       This function was introduced in openssl 0.9.5a. */
#else
    our_ssl_sessionid = SSL_get_session(connssl->handle);

    /* if SSL_get1_session() is unavailable, use SSL_get_session().
       This is an inferior option because the session can be flushed
       at any time by openssl. It is included only so curl compiles
       under versions of openssl < 0.9.5a.

       WARNING: How curl behaves if it's session is flushed is
       untested.
    */
#endif
    retcode = Curl_ssl_addsessionid(conn, our_ssl_sessionid,
                                    0 /* unknown size */);
    if(retcode) {
      failf(data, "failed to store ssl session");
      return retcode;
    }
  }


  /* Get server's certificate (note: beware of dynamic allocation) - opt */
  /* major serious hack alert -- we should check certificates
   * to authenticate the server; otherwise we risk man-in-the-middle
   * attack
   */

  connssl->server_cert = SSL_get_peer_certificate(connssl->handle);
  if(!connssl->server_cert) {
    failf(data, "SSL: couldn't get peer certificate!");
    return CURLE_SSL_PEER_CERTIFICATE;
  }
  infof (data, "Server certificate:\n");

  str = X509_NAME_oneline(X509_get_subject_name(connssl->server_cert),
                          NULL, 0);
  if(!str) {
    failf(data, "SSL: couldn't get X509-subject!");
    X509_free(connssl->server_cert);
    connssl->server_cert = NULL;
    return CURLE_SSL_CONNECT_ERROR;
  }
  infof(data, "\t subject: %s\n", str);
  CRYPTO_free(str);

  certdate = X509_get_notBefore(connssl->server_cert);
  Curl_ASN1_UTCTIME_output(conn, "\t start date: ", certdate);

  certdate = X509_get_notAfter(connssl->server_cert);
  Curl_ASN1_UTCTIME_output(conn, "\t expire date: ", certdate);

  if(data->set.ssl.verifyhost) {
    retcode = verifyhost(conn, connssl->server_cert);
    if(retcode) {
      X509_free(connssl->server_cert);
      connssl->server_cert = NULL;
      return retcode;
    }
  }

  str = X509_NAME_oneline(X509_get_issuer_name(connssl->server_cert),
                          NULL, 0);
  if(!str) {
    failf(data, "SSL: couldn't get X509-issuer name!");
    retcode = CURLE_SSL_CONNECT_ERROR;
  }
  else {
    infof(data, "\t issuer: %s\n", str);
    CRYPTO_free(str);

    /* We could do all sorts of certificate verification stuff here before
       deallocating the certificate. */

    lerr = data->set.ssl.certverifyresult=
      SSL_get_verify_result(connssl->handle);
    if(data->set.ssl.certverifyresult != X509_V_OK) {
      if(data->set.ssl.verifypeer) {
        /* We probably never reach this, because SSL_connect() will fail
           and we return earlyer if verifypeer is set? */
        failf(data, "SSL certificate verify result: %s (%ld)",
              X509_verify_cert_error_string(lerr), lerr);
        retcode = CURLE_SSL_PEER_CERTIFICATE;
      }
      else
        infof(data, "SSL certificate verify result: %s (%ld),"
              " continuing anyway.\n",
              X509_verify_cert_error_string(lerr), lerr);
    }
    else
      infof(data, "SSL certificate verify ok.\n");
  }

  X509_free(connssl->server_cert);
  connssl->server_cert = NULL;
  connssl->connecting_state = ssl_connect_done;
  return retcode;
}

static CURLcode
Curl_ossl_connect_common(struct connectdata *conn,
                         int sockindex,
                         bool nonblocking,
                         bool *done)
{
  CURLcode retcode;
  struct SessionHandle *data = conn->data;
  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
  curl_socket_t sockfd = conn->sock[sockindex];
  long timeout_ms;

  if (ssl_connect_1==connssl->connecting_state) {
    retcode = Curl_ossl_connect_step1(conn, sockindex);
    if (retcode)
      return retcode;
  }

  timeout_ms = 0;
  while (ssl_connect_2 == connssl->connecting_state ||
         ssl_connect_2_reading == connssl->connecting_state ||
         ssl_connect_2_writing == connssl->connecting_state) {

    /* if ssl is expecting something, check if it's available. */
    if (connssl->connecting_state == ssl_connect_2_reading
        || connssl->connecting_state == ssl_connect_2_writing) {

      int writefd = ssl_connect_2_writing==
        connssl->connecting_state?sockfd:CURL_SOCKET_BAD;
      int readfd = ssl_connect_2_reading==
        connssl->connecting_state?sockfd:CURL_SOCKET_BAD;

      while(1) {
        int what = Curl_select(readfd, writefd, nonblocking?0:(int)timeout_ms);
        if(what > 0)
          /* reabable or writable, go loop in the outer loop */
          break;
        else if(0 == what) {
          if (nonblocking) {
            *done = FALSE;
            return CURLE_OK;
          }
          else {
            /* timeout */
            failf(data, "SSL connection timeout");
            return CURLE_OPERATION_TIMEDOUT;
          }
        }
        else {
          /* anything that gets here is fatally bad */
          failf(data, "select on SSL socket, errno: %d", Curl_sockerrno());
          return CURLE_SSL_CONNECT_ERROR;
        }
      } /* while()-loop for the select() */
    }

    /* get the timeout from step2 to avoid computing it twice. */
    retcode = Curl_ossl_connect_step2(conn, sockindex, &timeout_ms);
    if (retcode)
      return retcode;

  } /* repeat step2 until all transactions are done. */


  if (ssl_connect_3==connssl->connecting_state) {
    retcode = Curl_ossl_connect_step3(conn, sockindex);
    if (retcode)
      return retcode;
  }

  if (ssl_connect_done==connssl->connecting_state) {
    *done = TRUE;
  }
  else {
    *done = FALSE;
  }

  /* Reset our connect state machine */
  connssl->connecting_state = ssl_connect_1;

  return CURLE_OK;
}

CURLcode
Curl_ossl_connect_nonblocking(struct connectdata *conn,
                              int sockindex,
                              bool *done)
{
  return Curl_ossl_connect_common(conn, sockindex, TRUE, done);
}

CURLcode
Curl_ossl_connect(struct connectdata *conn,
                  int sockindex)
{
  CURLcode retcode;
  bool done = FALSE;

  retcode = Curl_ossl_connect_common(conn, sockindex, FALSE, &done);
  if (retcode)
    return retcode;

  curlassert(done);

  return CURLE_OK;
}

/* return number of sent (non-SSL) bytes */
int Curl_ossl_send(struct connectdata *conn,
                   int sockindex,
                   void *mem,
                   size_t len)
{
  /* SSL_write() is said to return 'int' while write() and send() returns
     'size_t' */
  int err;
  char error_buffer[120]; /* OpenSSL documents that this must be at least 120
                             bytes long. */
  unsigned long sslerror;
  int rc = SSL_write(conn->ssl[sockindex].handle, mem, (int)len);

  if(rc < 0) {
    err = SSL_get_error(conn->ssl[sockindex].handle, rc);

    switch(err) {
    case SSL_ERROR_WANT_READ:
    case SSL_ERROR_WANT_WRITE:
      /* The operation did not complete; the same TLS/SSL I/O function
         should be called again later. This is basicly an EWOULDBLOCK
         equivalent. */
      return 0;
    case SSL_ERROR_SYSCALL:
      failf(conn->data, "SSL_write() returned SYSCALL, errno = %d\n",
            Curl_sockerrno());
      return -1;
    case SSL_ERROR_SSL:
      /*  A failure in the SSL library occurred, usually a protocol error.
          The OpenSSL error queue contains more information on the error. */
      sslerror = ERR_get_error();
      failf(conn->data, "SSL_write() error: %s\n",
            ERR_error_string(sslerror, error_buffer));
      return -1;
    }
    /* a true error */
    failf(conn->data, "SSL_write() return error %d\n", err);
    return -1;
  }
  return rc; /* number of bytes */
}

/*
 * If the read would block we return -1 and set 'wouldblock' to TRUE.
 * Otherwise we return the amount of data read. Other errors should return -1
 * and set 'wouldblock' to FALSE.
 */
ssize_t Curl_ossl_recv(struct connectdata *conn, /* connection data */
                       int num,                  /* socketindex */
                       char *buf,                /* store read data here */
                       size_t buffersize,        /* max amount to read */
                       bool *wouldblock)
{
  char error_buffer[120]; /* OpenSSL documents that this must be at
                             least 120 bytes long. */
  unsigned long sslerror;
  ssize_t nread = (ssize_t)SSL_read(conn->ssl[num].handle, buf,
                                    (int)buffersize);
  *wouldblock = FALSE;
  if(nread < 0) {
    /* failed SSL_read */
    int err = SSL_get_error(conn->ssl[num].handle, (int)nread);

    switch(err) {
    case SSL_ERROR_NONE: /* this is not an error */
    case SSL_ERROR_ZERO_RETURN: /* no more data */
      break;
    case SSL_ERROR_WANT_READ:
    case SSL_ERROR_WANT_WRITE:
      /* there's data pending, re-invoke SSL_read() */
      *wouldblock = TRUE;
      return -1; /* basically EWOULDBLOCK */
    default:
      /* openssl/ssl.h says "look at error stack/return value/errno" */
      sslerror = ERR_get_error();
      failf(conn->data, "SSL read: %s, errno %d",
            ERR_error_string(sslerror, error_buffer),
            Curl_sockerrno() );
      return -1;
    }
  }
  return nread;
}

size_t Curl_ossl_version(char *buffer, size_t size)
{
#ifdef YASSL_VERSION
  /* yassl provides an OpenSSL API compatiblity layer so it looks identical
     to OpenSSL in all other aspects */
  return snprintf(buffer, size, " yassl/%s", YASSL_VERSION);
#else /* YASSL_VERSION */

#if (SSLEAY_VERSION_NUMBER >= 0x905000)
  {
    char sub[2];
    unsigned long ssleay_value;
    sub[1]='\0';
    ssleay_value=SSLeay();
    if(ssleay_value < 0x906000) {
      ssleay_value=SSLEAY_VERSION_NUMBER;
      sub[0]='\0';
    }
    else {
      if(ssleay_value&0xff0) {
        sub[0]=(char)(((ssleay_value>>4)&0xff) + 'a' -1);
      }
      else
        sub[0]='\0';
    }

    return snprintf(buffer, size, " OpenSSL/%lx.%lx.%lx%s",
                    (ssleay_value>>28)&0xf,
                    (ssleay_value>>20)&0xff,
                    (ssleay_value>>12)&0xff,
                    sub);
  }

#else /* SSLEAY_VERSION_NUMBER is less than 0.9.5 */

#if (SSLEAY_VERSION_NUMBER >= 0x900000)
  return snprintf(buffer, size, " OpenSSL/%lx.%lx.%lx",
                  (SSLEAY_VERSION_NUMBER>>28)&0xff,
                  (SSLEAY_VERSION_NUMBER>>20)&0xff,
                  (SSLEAY_VERSION_NUMBER>>12)&0xf);

#else /* (SSLEAY_VERSION_NUMBER >= 0x900000) */
  {
    char sub[2];
    sub[1]='\0';
    if(SSLEAY_VERSION_NUMBER&0x0f) {
      sub[0]=(SSLEAY_VERSION_NUMBER&0x0f) + 'a' -1;
    }
    else
      sub[0]='\0';

    return snprintf(buffer, size, " SSL/%x.%x.%x%s",
                    (SSLEAY_VERSION_NUMBER>>12)&0xff,
                    (SSLEAY_VERSION_NUMBER>>8)&0xf,
                    (SSLEAY_VERSION_NUMBER>>4)&0xf, sub);
  }
#endif /* (SSLEAY_VERSION_NUMBER >= 0x900000) */
#endif /* SSLEAY_VERSION_NUMBER is less than 0.9.5 */

#endif /* YASSL_VERSION */
}
#endif /* USE_SSLEAY */