External signing callback interface.

	* includes/gnutls/gnutls.h.in (gnutls_sign_func): New type.
	(gnutls_sign_callback_set): New function.

	* includes/gnutls/x509.h (gnutls_x509_privkey_sign_hash): New
	function.

	* lib/gnutls_x509.c (gnutls_certificate_set_x509_key_mem): Handle
	NULL key.  Doc fix.

	* lib/gnutls_sig.c (_gnutls_tls_sign_hdata): Pass session to
	_gnutls_tls_sign.
	(_gnutls_tls_sign_params): Likewise.
	(_gnutls_tls_sign): Add new parameter 'session'.  Call sign
	callback if appropriate.
	(gnutls_sign_callback_set): New function.

	* lib/gnutls_x509.c (read_key_mem): Support a NULL key.

	* lib/gnutls_int.h (internals_st): Add sign_func,
	sign_func_userdata.

	* lib/auth_dhe.c (gen_dhe_server_kx): Use length of certificate
	list to decide wheter to sign, not presence of private key.
	* lib/auth_cert.c (_gnutls_gen_cert_client_cert_vrfy): Likewise.

	* lib/auth_rsa_export.c (gen_rsa_export_server_kx): Likewise.

	* lib/auth_cert.c(_gnutls_get_selected_cert): Don't require that
	private key is present.

	* lib/auth_rsa_export.c (gen_rsa_export_server_kx): Don't check
	key size when key is not present, assume it is > 512 bits.

	* lib/x509/privkey.c (gnutls_x509_privkey_sign_hash): New
	function.

	* tests/Makefile.am: Add x509signself.

1 files changed, 527 insertions, 0 deletions

diff --git a/tests/x509signself.c b/tests/x509signself.c
new file mode 100644
index 0000000000..2a0a44c591
--- /dev/null
+++ b/tests/x509signself.c
@@ -0,0 +1,527 @@
+/*
+ * Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation
+ *
+ * Author: Simon Josefsson
+ *
+ * This file is part of GNUTLS.
+ *
+ * GNUTLS is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GNUTLS is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNUTLS; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+/* Parts copied from GnuTLS example programs. */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
+
+#include "utils.h"
+
+pid_t child;
+
+static void
+tls_log_func (int level, const char *str)
+{
+  fprintf (stderr, "%s |<%d>| %s", child ? "server" : "client", level, str);
+}
+
+/* A very basic TLS client, with anonymous authentication.
+ */
+
+#define MAX_BUF 1024
+#define MSG "Hello TLS"
+
+/* Connects to the peer and returns a socket
+ * descriptor.
+ */
+int
+tcp_connect (void)
+{
+  const char *PORT = "5556";
+  const char *SERVER = "127.0.0.1";
+  int err, sd;
+  struct sockaddr_in sa;
+
+  /* connects to server
+   */
+  sd = socket (AF_INET, SOCK_STREAM, 0);
+
+  memset (&sa, '\0', sizeof (sa));
+  sa.sin_family = AF_INET;
+  sa.sin_port = htons (atoi (PORT));
+  inet_pton (AF_INET, SERVER, &sa.sin_addr);
+
+  err = connect (sd, (struct sockaddr *) &sa, sizeof (sa));
+  if (err < 0)
+    {
+      fprintf (stderr, "Connect error\n");
+      exit (1);
+    }
+
+  return sd;
+}
+
+/* closes the given socket descriptor.
+ */
+void
+tcp_close (int sd)
+{
+  shutdown (sd, SHUT_RDWR);	/* no more receptions */
+  close (sd);
+}
+
+const char ca_pem[] =
+  "-----BEGIN CERTIFICATE-----\n"
+  "MIIB5zCCAVKgAwIBAgIERiYdJzALBgkqhkiG9w0BAQUwGTEXMBUGA1UEAxMOR251\n"
+  "VExTIHRlc3QgQ0EwHhcNMDcwNDE4MTMyOTExWhcNMDgwNDE3MTMyOTExWjAZMRcw\n"
+  "FQYDVQQDEw5HbnVUTFMgdGVzdCBDQTCBnDALBgkqhkiG9w0BAQEDgYwAMIGIAoGA\n"
+  "vuyYeh1vfmslnuggeEKgZAVmQ5ltSdUY7H25WGSygKMUYZ0KT74v8C780qtcNt9T\n"
+  "7EPH/N6RvB4BprdssgcQLsthR3XKA84jbjjxNCcaGs33lvOz8A1nf8p3hD+cKfRi\n"
+  "kfYSW2JazLrtCC4yRCas/SPOUxu78of+3HiTfFm/oXUCAwEAAaNDMEEwDwYDVR0T\n"
+  "AQH/BAUwAwEB/zAPBgNVHQ8BAf8EBQMDBwQAMB0GA1UdDgQWBBTpPBz7rZJu5gak\n"
+  "Viyi4cBTJ8jylTALBgkqhkiG9w0BAQUDgYEAiaIRqGfp1jPpNeVhABK60SU0KIAy\n"
+  "njuu7kHq5peUgYn8Jd9zNzExBOEp1VOipGsf6G66oQAhDFp2o8zkz7ZH71zR4HEW\n"
+  "KoX6n5Emn6DvcEH/9pAhnGxNHJAoS7czTKv/JDZJhkqHxyrE1fuLsg5Qv25DTw7+\n"
+  "PfqUpIhz5Bbm7J4=\n"
+  "-----END CERTIFICATE-----\n";
+const gnutls_datum_t ca = { ca_pem, sizeof (ca_pem) };
+
+const char cert_pem[] =
+  "-----BEGIN CERTIFICATE-----\n"
+  "MIICHjCCAYmgAwIBAgIERiYdNzALBgkqhkiG9w0BAQUwGTEXMBUGA1UEAxMOR251\n"
+  "VExTIHRlc3QgQ0EwHhcNMDcwNDE4MTMyOTI3WhcNMDgwNDE3MTMyOTI3WjAdMRsw\n"
+  "GQYDVQQDExJHbnVUTFMgdGVzdCBjbGllbnQwgZwwCwYJKoZIhvcNAQEBA4GMADCB\n"
+  "iAKBgLtmQ/Xyxde2jMzF3/WIO7HJS2oOoa0gUEAIgKFPXKPQ+GzP5jz37AR2ExeL\n"
+  "ZIkiW8DdU3w77XwEu4C5KL6Om8aOoKUSy/VXHqLnu7czSZ/ju0quak1o/8kR4jKN\n"
+  "zj2AC41179gAgY8oBAOgIo1hBAf6tjd9IQdJ0glhaZiQo1ipAgMBAAGjdjB0MAwG\n"
+  "A1UdEwEB/wQCMAAwEwYDVR0lBAwwCgYIKwYBBQUHAwIwDwYDVR0PAQH/BAUDAweg\n"
+  "ADAdBgNVHQ4EFgQUTLkKm/odNON+3svSBxX+odrLaJEwHwYDVR0jBBgwFoAU6Twc\n"
+  "+62SbuYGpFYsouHAUyfI8pUwCwYJKoZIhvcNAQEFA4GBALujmBJVZnvaTXr9cFRJ\n"
+  "jpfc/3X7sLUsMvumcDE01ls/cG5mIatmiyEU9qI3jbgUf82z23ON/acwJf875D3/\n"
+  "U7jyOsBJ44SEQITbin2yUeJMIm1tievvdNXBDfW95AM507ShzP12sfiJkJfjjdhy\n"
+  "dc8Siq5JojruiMizAf0pA7in\n"
+  "-----END CERTIFICATE-----\n";
+const gnutls_datum_t cert = { cert_pem, sizeof (cert_pem) };
+
+int
+sign_func (gnutls_session_t session,
+	   void *userdata,
+	   gnutls_certificate_type_t cert_type,
+	   gnutls_datum_t cert,
+	   const gnutls_datum_t hash,
+	   gnutls_datum_t * signature)
+{
+  gnutls_x509_privkey_t key;
+  const char key_pem[] =
+    "-----BEGIN RSA PRIVATE KEY-----\n"
+    "MIICXAIBAAKBgQC7ZkP18sXXtozMxd/1iDuxyUtqDqGtIFBACIChT1yj0Phsz+Y8\n"
+    "9+wEdhMXi2SJIlvA3VN8O+18BLuAuSi+jpvGjqClEsv1Vx6i57u3M0mf47tKrmpN\n"
+    "aP/JEeIyjc49gAuNde/YAIGPKAQDoCKNYQQH+rY3fSEHSdIJYWmYkKNYqQIDAQAB\n"
+    "AoGADpmARG5CQxS+AesNkGmpauepiCz1JBF/JwnyiX6vEzUh0Ypd39SZztwrDxvF\n"
+    "PJjQaKVljml1zkJpIDVsqvHdyVdse8M+Qn6hw4x2p5rogdvhhIL1mdWo7jWeVJTF\n"
+    "RKB7zLdMPs3ySdtcIQaF9nUAQ2KJEvldkO3m/bRJFEp54k0CQQDYy+RlTmwRD6hy\n"
+    "7UtMjR0H3CSZJeQ8svMCxHLmOluG9H1UKk55ZBYfRTsXniqUkJBZ5wuV1L+pR9EK\n"
+    "ca89a+1VAkEA3UmBelwEv2u9cAU1QjKjmwju1JgXbrjEohK+3B5y0ESEXPAwNQT9\n"
+    "TrDM1m9AyxYTWLxX93dI5QwNFJtmbtjeBQJARSCWXhsoaDRG8QZrCSjBxfzTCqZD\n"
+    "ZXtl807ymCipgJm60LiAt0JLr4LiucAsMZz6+j+quQbSakbFCACB8SLV1QJBAKZQ\n"
+    "YKf+EPNtnmta/rRKKvySsi3GQZZN+Dt3q0r094XgeTsAqrqujVNfPhTMeP4qEVBX\n"
+    "/iVX2cmMTSh3w3z8MaECQEp0XJWDVKOwcTW6Ajp9SowtmiZ3YDYo1LF9igb4iaLv\n"
+    "sWZGfbnU3ryjvkb6YuFjgtzbZDZHWQCo8/cOtOBmPdk=\n"
+    "-----END RSA PRIVATE KEY-----\n";
+  const gnutls_datum_t key_dat = { key_pem, sizeof (key_pem) };
+  int ret;
+
+  ret = gnutls_x509_privkey_init (&key);
+  if (ret < 0)
+    return ret;
+
+  ret = gnutls_x509_privkey_import (key, &key_dat, GNUTLS_X509_FMT_PEM);
+  if (ret < 0)
+    goto done;
+
+  ret = gnutls_x509_privkey_sign_hash (key, hash, signature);
+  if (ret < 0)
+    goto done;
+
+  ret = 0;
+
+ done:
+  gnutls_x509_privkey_deinit (key);
+  return ret;
+}
+
+void
+client (void)
+{
+  int ret, sd, ii;
+  gnutls_session_t session;
+  char buffer[MAX_BUF + 1];
+  gnutls_certificate_credentials_t xcred;
+
+  gnutls_global_init ();
+
+  gnutls_global_set_log_function (tls_log_func);
+  gnutls_global_set_log_level (4711);
+
+  gnutls_certificate_allocate_credentials (&xcred);
+
+  /* sets the trusted cas file
+   */
+  gnutls_certificate_set_x509_trust_mem (xcred, &ca, GNUTLS_X509_FMT_PEM);
+  gnutls_certificate_set_x509_key_mem (xcred, &cert, NULL,
+				       GNUTLS_X509_FMT_PEM);
+
+  /* Initialize TLS session
+   */
+  gnutls_init (&session, GNUTLS_CLIENT);
+
+  /* Set sign callback. */
+  gnutls_sign_callback_set (session, sign_func, NULL);
+
+  /* Use default priorities */
+  gnutls_set_default_priority (session);
+
+  /* put the x509 credentials to the current session
+   */
+  gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, xcred);
+
+  /* connect to the peer
+   */
+  sd = tcp_connect ();
+
+  gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
+
+  /* Perform the TLS handshake
+   */
+  ret = gnutls_handshake (session);
+
+  if (ret < 0)
+    {
+      fail ("client: Handshake failed\n");
+      gnutls_perror (ret);
+      goto end;
+    }
+  else
+    {
+      success ("client: Handshake was completed\n");
+    }
+
+  success ("client: TLS version is: %s\n",
+	   gnutls_protocol_get_name (gnutls_protocol_get_version (session)));
+
+  /* see the Getting peer's information example */
+  print_info(session);
+
+  gnutls_record_send (session, MSG, strlen (MSG));
+
+  ret = gnutls_record_recv (session, buffer, MAX_BUF);
+  if (ret == 0)
+    {
+      success ("client: Peer has closed the TLS connection\n");
+      goto end;
+    }
+  else if (ret < 0)
+    {
+      fail ("client: Error: %s\n", gnutls_strerror (ret));
+      goto end;
+    }
+
+  printf ("- Received %d bytes: ", ret);
+  for (ii = 0; ii < ret; ii++)
+    {
+      fputc (buffer[ii], stdout);
+    }
+  fputs ("\n", stdout);
+
+  gnutls_bye (session, GNUTLS_SHUT_RDWR);
+
+end:
+
+  tcp_close (sd);
+
+  gnutls_deinit (session);
+
+  gnutls_certificate_free_credentials (xcred);
+
+  gnutls_global_deinit ();
+}
+
+/* This is a sample TLS 1.0 echo server, using X.509 authentication.
+ */
+
+#define SA struct sockaddr
+#define MAX_BUF 1024
+#define PORT 5556		/* listen to 5556 port */
+#define DH_BITS 1024
+
+/* These are global */
+gnutls_certificate_credentials_t x509_cred;
+
+gnutls_session_t
+initialize_tls_session (void)
+{
+  gnutls_session_t session;
+
+  gnutls_init (&session, GNUTLS_SERVER);
+
+  /* avoid calling all the priority functions, since the defaults
+   * are adequate.
+   */
+  gnutls_set_default_priority (session);
+
+  gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, x509_cred);
+
+  /* request client certificate if any.
+   */
+  gnutls_certificate_server_set_request (session, GNUTLS_CERT_REQUEST);
+
+  gnutls_dh_set_prime_bits (session, DH_BITS);
+
+  return session;
+}
+
+static gnutls_dh_params_t dh_params;
+
+static int
+generate_dh_params (void)
+{
+  const gnutls_datum_t p3 = { pkcs3, strlen (pkcs3) };
+  /* Generate Diffie Hellman parameters - for use with DHE
+   * kx algorithms. These should be discarded and regenerated
+   * once a day, once a week or once a month. Depending on the
+   * security requirements.
+   */
+  gnutls_dh_params_init (&dh_params);
+  return gnutls_dh_params_import_pkcs3 (dh_params, &p3, GNUTLS_X509_FMT_PEM);
+}
+
+int err, listen_sd, i;
+int sd, ret;
+struct sockaddr_in sa_serv;
+struct sockaddr_in sa_cli;
+int client_len;
+char topbuf[512];
+gnutls_session_t session;
+char buffer[MAX_BUF + 1];
+int optval = 1;
+
+
+const char server_cert_pem[] =
+  "-----BEGIN CERTIFICATE-----\n"
+  "MIICVjCCAcGgAwIBAgIERiYdMTALBgkqhkiG9w0BAQUwGTEXMBUGA1UEAxMOR251\n"
+  "VExTIHRlc3QgQ0EwHhcNMDcwNDE4MTMyOTIxWhcNMDgwNDE3MTMyOTIxWjA3MRsw\n"
+  "GQYDVQQKExJHbnVUTFMgdGVzdCBzZXJ2ZXIxGDAWBgNVBAMTD3Rlc3QuZ251dGxz\n"
+  "Lm9yZzCBnDALBgkqhkiG9w0BAQEDgYwAMIGIAoGA17pcr6MM8C6pJ1aqU46o63+B\n"
+  "dUxrmL5K6rce+EvDasTaDQC46kwTHzYWk95y78akXrJutsoKiFV1kJbtple8DDt2\n"
+  "DZcevensf9Op7PuFZKBroEjOd35znDET/z3IrqVgbtm2jFqab7a+n2q9p/CgMyf1\n"
+  "tx2S5Zacc1LWn9bIjrECAwEAAaOBkzCBkDAMBgNVHRMBAf8EAjAAMBoGA1UdEQQT\n"
+  "MBGCD3Rlc3QuZ251dGxzLm9yZzATBgNVHSUEDDAKBggrBgEFBQcDATAPBgNVHQ8B\n"
+  "Af8EBQMDB6AAMB0GA1UdDgQWBBTrx0Vu5fglyoyNgw106YbU3VW0dTAfBgNVHSME\n"
+  "GDAWgBTpPBz7rZJu5gakViyi4cBTJ8jylTALBgkqhkiG9w0BAQUDgYEAaFEPTt+7\n"
+  "bzvBuOf7+QmeQcn29kT6Bsyh1RHJXf8KTk5QRfwp6ogbp94JQWcNQ/S7YDFHglD1\n"
+  "AwUNBRXwd3riUsMnsxgeSDxYBfJYbDLeohNBsqaPDJb7XailWbMQKfAbFQ8cnOxg\n"
+  "rOKLUQRWJ0K3HyXRMhbqjdLIaQiCvQLuizo=\n"
+  "-----END CERTIFICATE-----\n";
+
+const gnutls_datum_t server_cert = { server_cert_pem,
+				     sizeof (server_cert_pem) };
+
+const char server_key_pem[] =
+  "-----BEGIN RSA PRIVATE KEY-----\n"
+  "MIICXAIBAAKBgQDXulyvowzwLqknVqpTjqjrf4F1TGuYvkrqtx74S8NqxNoNALjq\n"
+  "TBMfNhaT3nLvxqResm62ygqIVXWQlu2mV7wMO3YNlx696ex/06ns+4VkoGugSM53\n"
+  "fnOcMRP/PciupWBu2baMWppvtr6far2n8KAzJ/W3HZLllpxzUtaf1siOsQIDAQAB\n"
+  "AoGAYAFyKkAYC/PYF8e7+X+tsVCHXppp8AoP8TEZuUqOZz/AArVlle/ROrypg5kl\n"
+  "8YunrvUdzH9R/KZ7saNZlAPLjZyFG9beL/am6Ai7q7Ma5HMqjGU8kTEGwD7K+lbG\n"
+  "iomokKMOl+kkbY/2sI5Czmbm+/PqLXOjtVc5RAsdbgvtmvkCQQDdV5QuU8jap8Hs\n"
+  "Eodv/tLJ2z4+SKCV2k/7FXSKWe0vlrq0cl2qZfoTUYRnKRBcWxc9o92DxK44wgPi\n"
+  "oMQS+O7fAkEA+YG+K9e60sj1K4NYbMPAbYILbZxORDecvP8lcphvwkOVUqbmxOGh\n"
+  "XRmTZUuhBrJhJKKf6u7gf3KWlPl6ShKEbwJASC118cF6nurTjuLf7YKARDjNTEws\n"
+  "qZEeQbdWYINAmCMj0RH2P0mvybrsXSOD5UoDAyO7aWuqkHGcCLv6FGG+qwJAOVqq\n"
+  "tXdUucl6GjOKKw5geIvRRrQMhb/m5scb+5iw8A4LEEHPgGiBaF5NtJZLALgWfo5n\n"
+  "hmC8+G8F0F78znQtPwJBANexu+Tg5KfOnzSILJMo3oXiXhf5PqXIDmbN0BKyCKAQ\n"
+  "LfkcEcUbVfmDaHpvzwY9VEaoMOKVLitETXdNSxVpvWM=\n"
+  "-----END RSA PRIVATE KEY-----\n";
+
+const gnutls_datum_t server_key = { server_key_pem,
+				    sizeof (server_key_pem) };
+
+void
+server_start (void)
+{
+  /* this must be called once in the program
+   */
+  gnutls_global_init ();
+
+  gnutls_global_set_log_function (tls_log_func);
+  gnutls_global_set_log_level (4711);
+
+  gnutls_certificate_allocate_credentials (&x509_cred);
+  gnutls_certificate_set_x509_trust_mem (x509_cred, &ca, GNUTLS_X509_FMT_PEM);
+
+  gnutls_certificate_set_x509_key_mem (x509_cred, &server_cert, &server_key,
+				       GNUTLS_X509_FMT_PEM);
+
+  success ("Launched, generating DH parameters...\n");
+
+  generate_dh_params ();
+
+  gnutls_certificate_set_dh_params (x509_cred, dh_params);
+
+  /* Socket operations
+   */
+  listen_sd = socket (AF_INET, SOCK_STREAM, 0);
+  if (err == -1)
+    {
+      perror ("socket");
+      fail ("server: socket failed\n");
+      return;
+    }
+
+  memset (&sa_serv, '\0', sizeof (sa_serv));
+  sa_serv.sin_family = AF_INET;
+  sa_serv.sin_addr.s_addr = INADDR_ANY;
+  sa_serv.sin_port = htons (PORT);	/* Server Port number */
+
+  setsockopt (listen_sd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof (int));
+
+  err = bind (listen_sd, (SA *) & sa_serv, sizeof (sa_serv));
+  if (err == -1)
+    {
+      perror ("bind");
+      fail ("server: bind failed\n");
+      return;
+    }
+
+  err = listen (listen_sd, 1024);
+  if (err == -1)
+    {
+      perror ("listen");
+      fail ("server: listen failed\n");
+      return;
+    }
+
+  success ("server: ready. Listening to port '%d'.\n", PORT);
+}
+
+#include "ex-session-info.c"
+#include "ex-x509-info.c"
+
+void
+server (void)
+{
+  client_len = sizeof (sa_cli);
+
+  session = initialize_tls_session ();
+
+  sd = accept (listen_sd, (SA *) & sa_cli, &client_len);
+
+  success ("server: connection from %s, port %d\n",
+	   inet_ntop (AF_INET, &sa_cli.sin_addr, topbuf,
+		      sizeof (topbuf)), ntohs (sa_cli.sin_port));
+
+  gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
+  ret = gnutls_handshake (session);
+  if (ret < 0)
+    {
+      close (sd);
+      gnutls_deinit (session);
+      fail ("server: Handshake has failed (%s)\n\n", gnutls_strerror (ret));
+      return;
+    }
+  success ("server: Handshake was completed\n");
+
+  success ("server: TLS version is: %s\n",
+	   gnutls_protocol_get_name (gnutls_protocol_get_version (session)));
+
+  /* see the Getting peer's information example */
+  print_info(session);
+
+  i = 0;
+  for (;;)
+    {
+      bzero (buffer, MAX_BUF + 1);
+      ret = gnutls_record_recv (session, buffer, MAX_BUF);
+
+      if (ret == 0)
+	{
+	  success ("server: Peer has closed the GNUTLS connection\n");
+	  break;
+	}
+      else if (ret < 0)
+	{
+	  fail ("server: Received corrupted data(%d). Closing...\n", ret);
+	  break;
+	}
+      else if (ret > 0)
+	{
+	  /* echo data back to the client
+	   */
+	  gnutls_record_send (session, buffer, strlen (buffer));
+	}
+    }
+  /* do not wait for the peer to close the connection.
+   */
+  gnutls_bye (session, GNUTLS_SHUT_WR);
+
+  close (sd);
+  gnutls_deinit (session);
+
+  close (listen_sd);
+
+  gnutls_certificate_free_credentials (x509_cred);
+
+  gnutls_global_deinit ();
+
+  success ("server: finished\n");
+}
+
+
+void
+doit (void)
+{
+  server_start ();
+  if (error_count)
+    return;
+
+  child = fork ();
+  if (child < 0)
+    {
+      perror ("fork");
+      fail ("fork");
+      return;
+    }
+
+  if (child)
+    {
+      int status;
+      /* parent */
+      server ();
+      wait (&status);
+    }
+  else
+    client ();
+}