1/*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 9 * 10 * This software is licensed as described in the file COPYING, which 11 * you should have received as part of this distribution. The terms 12 * are also available at https://curl.se/docs/copyright.html. 13 * 14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell 15 * copies of the Software, and permit persons to whom the Software is 16 * furnished to do so, under the terms of the COPYING file. 17 * 18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY 19 * KIND, either express or implied. 20 * 21 * SPDX-License-Identifier: curl 22 * 23 ***************************************************************************/ 24 25#include "curl_setup.h" 26 27#include "curl_gethostname.h" 28 29/* 30 * Curl_gethostname() is a wrapper around gethostname() which allows 31 * overriding the host name that the function would normally return. 32 * This capability is used by the test suite to verify exact matching 33 * of NTLM authentication, which exercises libcurl's MD4 and DES code 34 * as well as by the SMTP module when a hostname is not provided. 35 * 36 * For libcurl debug enabled builds host name overriding takes place 37 * when environment variable CURL_GETHOSTNAME is set, using the value 38 * held by the variable to override returned host name. 39 * 40 * Note: The function always returns the un-qualified hostname rather 41 * than being provider dependent. 42 * 43 * For libcurl shared library release builds the test suite preloads 44 * another shared library named libhostname using the LD_PRELOAD 45 * mechanism which intercepts, and might override, the gethostname() 46 * function call. In this case a given platform must support the 47 * LD_PRELOAD mechanism and additionally have environment variable 48 * CURL_GETHOSTNAME set in order to override the returned host name. 49 * 50 * For libcurl static library release builds no overriding takes place. 51 */ 52 53int Curl_gethostname(char * const name, GETHOSTNAME_TYPE_ARG2 namelen) 54{ 55#ifndef HAVE_GETHOSTNAME 56 57 /* Allow compilation and return failure when unavailable */ 58 (void) name; 59 (void) namelen; 60 return -1; 61 62#else 63 int err; 64 char *dot; 65 66#ifdef DEBUGBUILD 67 68 /* Override host name when environment variable CURL_GETHOSTNAME is set */ 69 const char *force_hostname = getenv("CURL_GETHOSTNAME"); 70 if(force_hostname) { 71 strncpy(name, force_hostname, namelen); 72 err = 0; 73 } 74 else { 75 name[0] = '\0'; 76 err = gethostname(name, namelen); 77 } 78 79#else /* DEBUGBUILD */ 80 81 /* The call to system's gethostname() might get intercepted by the 82 libhostname library when libcurl is built as a non-debug shared 83 library when running the test suite. */ 84 name[0] = '\0'; 85 err = gethostname(name, namelen); 86 87#endif 88 89 name[namelen - 1] = '\0'; 90 91 if(err) 92 return err; 93 94 /* Truncate domain, leave only machine name */ 95 dot = strchr(name, '.'); 96 if(dot) 97 *dot = '\0'; 98 99 return 0; 100#endif 101 102} 103