lib/krb5/expand_hostname.c

   1 /*
   2  * Copyright (c) 1999 - 2000 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "krb5_locl.h"
  35
  36 RCSID("$Id$");
  37
  38 static krb5_error_code
  39 copy_hostname(krb5_context context,
  40               const char *orig_hostname,
  41               char **new_hostname)
  42 {
  43     *new_hostname = strdup (orig_hostname);
  44     if (*new_hostname == NULL)
  45         return ENOMEM;
  46     strlwr (*new_hostname);
  47     return 0;
  48 }
  49
  50 /*
  51  * Try to make `orig_hostname' into a more canonical one in the newly
  52  * allocated space returned in `new_hostname'.
  53  */
  54
  55 krb5_error_code
  56 krb5_expand_hostname (krb5_context context,
  57                       const char *orig_hostname,
  58                       char **new_hostname)
  59 {
  60     struct addrinfo *ai, *a, hints;
  61     int error;
  62
  63     memset (&hints, 0, sizeof(hints));
  64     hints.ai_flags = AI_CANONNAME;
  65
  66     error = getaddrinfo (orig_hostname, NULL, &hints, &ai);
  67     if (error)
  68         return copy_hostname (context, orig_hostname, new_hostname);
  69     for (a = ai; a != NULL; a = a->ai_next) {
  70         if (a->ai_canonname != NULL) {
  71             *new_hostname = strdup (a->ai_canonname);
  72             freeaddrinfo (ai);
  73             if (*new_hostname == NULL)
  74                 return ENOMEM;
  75             else
  76                 return 0;
  77         }
  78     }
  79     freeaddrinfo (ai);
  80     return copy_hostname (context, orig_hostname, new_hostname);
  81 }
  82
  83 /*
  84  * expand `hostname' to a name we believe to be a hostname in newly
  85  * allocated space in `host' and return realms in `realms'.
  86  */
  87
  88 krb5_error_code
  89 krb5_expand_hostname_realms (krb5_context context,
  90                              const char *orig_hostname,
  91                              char **new_hostname,
  92                              char ***realms)
  93 {
  94     struct addrinfo *ai, *a, hints;
  95     int error;
  96     krb5_error_code ret = 0;
  97
  98     memset (&hints, 0, sizeof(hints));
  99     hints.ai_flags = AI_CANONNAME;
 100
 101     error = getaddrinfo (orig_hostname, NULL, &hints, &ai);
 102     if (error)
 103         return copy_hostname (context, orig_hostname, new_hostname);
 104     for (a = ai; a != NULL; a = a->ai_next) {
 105         if (a->ai_canonname != NULL) {
 106             ret = copy_hostname (context, orig_hostname, new_hostname);
 107             if (ret)
 108                 goto out;
 109             strlwr (*new_hostname);
 110             ret = krb5_get_host_realm (context, *new_hostname, realms);
 111             if (ret == 0)
 112                 goto out;
 113             free (*new_hostname);
 114         }
 115     }
 116     ret = copy_hostname (context, orig_hostname, new_hostname);
 117  out:
 118     freeaddrinfo (ai);
 119     return ret;
 120 }