diplodocus.org Git - nmh/blob - mts/smtp/hosts.c

   1
   2 /*
   3  * hosts.c -- find out the official name of a host
   4  *
   5  * $Id$
   6  *
   7  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   8  * COPYRIGHT file in the root directory of the nmh distribution for
   9  * complete copyright information.
  10  */
  11
  12 /*
  13  * In the SendMail world, we really don't know what the valid
  14  * hosts are.  We could poke around in the sendmail.cf file, but
  15  * that still isn't a guarantee.  As a result, we'll say that
  16  * everything is a valid host, and let SendMail worry about it.
  17  */
  18
  19 #include <h/mh.h>
  20 #include <h/mts.h>
  21 #include <netdb.h>
  22
  23 static struct host {
  24     char *h_name;
  25     char **h_aliases;
  26     struct host *h_next;
  27 } hosts;
  28
  29
  30 /*
  31  * static prototypes
  32  */
  33 static int init_hs(void);
  34
  35
  36 char *
  37 OfficialName (char *name)
  38 {
  39     unsigned char *p;
  40     char *q, site[BUFSIZ];
  41     struct addrinfo hints, *res;
  42
  43     static char buffer[BUFSIZ];
  44     char **r;
  45     struct host *h;
  46
  47     for (p = name, q = site; *p && (q - site < sizeof(site) - 1); p++, q++)
  48         *q = isupper (*p) ? tolower (*p) : *p;
  49     *q = '\0';
  50     q = site;
  51
  52     if (!mh_strcasecmp (LocalName(), site))
  53         return LocalName();
  54
  55     memset(&hints, 0, sizeof(hints));
  56     hints.ai_flags = AI_CANONNAME;
  57     hints.ai_family = PF_UNSPEC;
  58
  59     if (getaddrinfo(q, NULL, &hints, &res) == 0) {
  60         strncpy (buffer, res->ai_canonname, sizeof(buffer));
  61         buffer[sizeof(buffer) - 1] = '\0';
  62         freeaddrinfo(res);
  63         return buffer;
  64     }
  65     if (hosts.h_name || init_hs ()) {
  66         for (h = hosts.h_next; h; h = h->h_next)
  67             if (!mh_strcasecmp (h->h_name, q)) {
  68                 return h->h_name;
  69             } else {
  70                 for (r = h->h_aliases; *r; r++)
  71                     if (!mh_strcasecmp (*r, q))
  72                         return h->h_name;
  73             }
  74     }
  75
  76     strncpy (buffer, site, sizeof(buffer));
  77     return buffer;
  78 }
  79
  80 /*
  81  * Use hostable as an exception file for those hosts that aren't
  82  * on the Internet (listed in /etc/hosts).  These are usually
  83  * PhoneNet and UUCP sites.
  84  */
  85
  86 #define NALIASES 50
  87
  88 static int
  89 init_hs (void)
  90 {
  91     unsigned char  *cp;
  92     char *dp, **q, **r;
  93     char buffer[BUFSIZ], *aliases[NALIASES];
  94     register struct host *h;
  95     register FILE  *fp;
  96
  97     if ((fp = fopen (hostable, "r")) == NULL)
  98         return 0;
  99
 100     h = &hosts;
 101     while (fgets (buffer, sizeof(buffer), fp) != NULL) {
 102         if ((cp = strchr(buffer, '#')))
 103             *cp = 0;
 104         if ((cp = strchr(buffer, '\n')))
 105             *cp = 0;
 106         for (cp = buffer; *cp; cp++)
 107             if (isspace (*cp))
 108                 *cp = ' ';
 109         for (cp = buffer; isspace (*cp); cp++)
 110             continue;
 111         if (*cp == 0)
 112             continue;
 113
 114         q = aliases;
 115         if ((cp = strchr(dp = cp, ' '))) {
 116             *cp = 0;
 117             for (cp++; *cp; cp++) {
 118                 while (isspace (*cp))
 119                     cp++;
 120                 if (*cp == 0)
 121                     break;
 122                 if ((cp = strchr(*q++ = cp, ' ')))
 123                     *cp = 0;
 124                 else
 125                     break;
 126                 if (q >= aliases + NALIASES)
 127                     break;
 128             }
 129         }
 130
 131         *q = 0;
 132
 133         h->h_next = (struct host *) calloc (1, sizeof(*h));
 134         h = h->h_next;
 135         h->h_name = getcpy (dp);
 136         r = h->h_aliases =
 137                 (char **) calloc ((size_t) (q - aliases + 1), sizeof(*q));
 138         for (q = aliases; *q; q++)
 139             *r++ = getcpy (*q);
 140         *r = 0;
 141     }
 142
 143     fclose (fp);
 144     return 1;
 145 }