1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2010, 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 http://curl.haxx.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 ***************************************************************************/
22
23#include "setup.h"
24
25#ifdef HAVE_UNISTD_H
26#  include <unistd.h>
27#endif
28
29#include "curl_gethostname.h"
30
31/*
32 * Curl_gethostname() is a wrapper around gethostname() which allows
33 * overriding the host name that the function would normally return.
34 * This capability is used by the test suite to verify exact matching
35 * of NTLM authentication, which exercises libcurl's MD4 and DES code.
36 *
37 * For libcurl debug enabled builds host name overriding takes place
38 * when environment variable CURL_GETHOSTNAME is set, using the value
39 * held by the variable to override returned host name.
40 *
41 * For libcurl shared library release builds the test suite preloads
42 * another shared library named libhostname using the LD_PRELOAD
43 * mechanism which intercepts, and might override, the gethostname()
44 * function call. In this case a given platform must support the
45 * LD_PRELOAD mechanism and additionally have environment variable
46 * CURL_GETHOSTNAME set in order to override the returned host name.
47 *
48 * For libcurl static library release builds no overriding takes place.
49 */
50
51int Curl_gethostname(char *name, GETHOSTNAME_TYPE_ARG2 namelen) {
52
53#ifndef HAVE_GETHOSTNAME
54
55  /* Allow compilation and return failure when unavailable */
56  (void) name;
57  (void) namelen;
58  return -1;
59
60#else
61
62#ifdef DEBUGBUILD
63
64  /* Override host name when environment variable CURL_GETHOSTNAME is set */
65  const char *force_hostname = getenv("CURL_GETHOSTNAME");
66  if(force_hostname) {
67    strncpy(name, force_hostname, namelen);
68    name[namelen-1] = '\0';
69    return 0;
70  }
71
72#endif /* DEBUGBUILD */
73
74  /* The call to system's gethostname() might get intercepted by the
75     libhostname library when libcurl is built as a non-debug shared
76     library when running the test suite. */
77  return gethostname(name, namelen);
78
79#endif
80
81}
82