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

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