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/*************************************************************************** 
 *                                  _   _ ____  _ 
 *  Project                     ___| | | |  _ \| | 
 *                             / __| | | | |_) | | 
 *                            | (__| |_| |  _ <| |___ 
 *                             \___|\___/|_| \_\_____| 
 * 
 * Copyright (C) 1998 - 2020, 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. 
 * 
 ***************************************************************************/ 
 
#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 
 
}