/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms

 * are also available at https://curl.se/docs/copyright.html.

 *

 * You may opt to use, copy, modify, merge, publish, distribute and/or sell

 * copies of the Software, and permit persons to whom the Software is

 * furnished to do so, under the terms of the COPYING file.

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY

 * KIND, either express or implied.

 *

 * SPDX-License-Identifier: curl

 *

 ***************************************************************************/

#include "curl_setup.h"

#include "curl_gethostname.h"

/*

 * Curl_gethostname() is a wrapper around gethostname() which allows

 * overriding the host name that the function would normally return.

 * This capability is used by the test suite to verify exact matching

 * of NTLM authentication, which exercises libcurl's MD4 and DES code

 * as well as by the SMTP module when a hostname is not provided.

 *

 * For libcurl debug enabled builds host name overriding takes place

 * when environment variable CURL_GETHOSTNAME is set, using the value

 * held by the variable to override returned host name.

 *

 * Note: The function always returns the un-qualified hostname rather

 * than being provider dependent.

 *

 * For libcurl shared library release builds the test suite preloads

 * another shared library named libhostname using the LD_PRELOAD

 * mechanism which intercepts, and might override, the gethostname()

 * function call. In this case a given platform must support the

 * LD_PRELOAD mechanism and additionally have environment variable

 * CURL_GETHOSTNAME set in order to override the returned host name.

 *

 * For libcurl static library release builds no overriding takes place.

 */

int Curl_gethostname(char * const name, GETHOSTNAME_TYPE_ARG2 namelen)

{

#ifndef HAVE_GETHOSTNAME

  /* Allow compilation and return failure when unavailable */

  (void) name;

  (void) namelen;

  return -1;

#else

  int err;

  char *dot;

#ifdef DEBUGBUILD

  /* Override host name when environment variable CURL_GETHOSTNAME is set */

  const char *force_hostname = getenv("CURL_GETHOSTNAME");

  if(force_hostname) {

    strncpy(name, force_hostname, namelen);

    err = 0;

  }

  else {

    name[0] = '\0';

    err = gethostname(name, namelen);

  }

#else /* DEBUGBUILD */

  /* The call to system's gethostname() might get intercepted by the

     libhostname library when libcurl is built as a non-debug shared

     library when running the test suite. */

  name[0] = '\0';

  err = gethostname(name, namelen);

#endif

  name[namelen - 1] = '\0';

  if(err)

    return err;

  /* Truncate domain, leave only machine name */

  dot = strchr(name, '.');

  if(dot)

    *dot = '\0';

  return 0;

#endif

}