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Annotation of embedaddon/curl/lib/curl_gethostname.c, revision 1.1.1.1

1.1       misho       1: /***************************************************************************
                      2:  *                                  _   _ ____  _
                      3:  *  Project                     ___| | | |  _ \| |
                      4:  *                             / __| | | | |_) | |
                      5:  *                            | (__| |_| |  _ <| |___
                      6:  *                             \___|\___/|_| \_\_____|
                      7:  *
                      8:  * Copyright (C) 1998 - 2016, 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.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 "curl_setup.h"
                     24: 
                     25: #include "curl_gethostname.h"
                     26: 
                     27: /*
                     28:  * Curl_gethostname() is a wrapper around gethostname() which allows
                     29:  * overriding the host name that the function would normally return.
                     30:  * This capability is used by the test suite to verify exact matching
                     31:  * of NTLM authentication, which exercises libcurl's MD4 and DES code
                     32:  * as well as by the SMTP module when a hostname is not provided.
                     33:  *
                     34:  * For libcurl debug enabled builds host name overriding takes place
                     35:  * when environment variable CURL_GETHOSTNAME is set, using the value
                     36:  * held by the variable to override returned host name.
                     37:  *
                     38:  * Note: The function always returns the un-qualified hostname rather
                     39:  * than being provider dependent.
                     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: 
                     51: int 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:   int err;
                     62:   char *dot;
                     63: 
                     64: #ifdef DEBUGBUILD
                     65: 
                     66:   /* Override host name when environment variable CURL_GETHOSTNAME is set */
                     67:   const char *force_hostname = getenv("CURL_GETHOSTNAME");
                     68:   if(force_hostname) {
                     69:     strncpy(name, force_hostname, namelen);
                     70:     err = 0;
                     71:   }
                     72:   else {
                     73:     name[0] = '\0';
                     74:     err = gethostname(name, namelen);
                     75:   }
                     76: 
                     77: #else /* DEBUGBUILD */
                     78: 
                     79:   /* The call to system's gethostname() might get intercepted by the
                     80:      libhostname library when libcurl is built as a non-debug shared
                     81:      library when running the test suite. */
                     82:   name[0] = '\0';
                     83:   err = gethostname(name, namelen);
                     84: 
                     85: #endif
                     86: 
                     87:   name[namelen - 1] = '\0';
                     88: 
                     89:   if(err)
                     90:     return err;
                     91: 
                     92:   /* Truncate domain, leave only machine name */
                     93:   dot = strchr(name, '.');
                     94:   if(dot)
                     95:     *dot = '\0';
                     96: 
                     97:   return 0;
                     98: #endif
                     99: 
                    100: }