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 <sys/socket.h>
  20 #include <netdb.h>
  21
  22 static struct host {
  23     char *h_name;
  24     char **h_aliases;
  25     struct host *h_next;
  26 } hosts;
  27
  28
  29 /*
  30  * static prototypes
  31  */
  32 static int init_hs(void);
  33
  34
  35 char *
  36 OfficialName (char *name)
  37 {
  38     unsigned char *p;
  39     char *q, site[BUFSIZ];
  40     struct addrinfo hints, *res;
  41
  42     static char buffer[BUFSIZ];
  43     char **r;
  44     struct host *h;
  45
  46     for (p = name, q = site; *p && (q - site < sizeof(site) - 1); p++, q++)
  47         *q = isupper (*p) ? tolower (*p) : *p;
  48     *q = '\0';
  49     q = site;
  50
  51     if (!mh_strcasecmp (LocalName(), site))
  52         return LocalName();
  53
  54     memset(&hints, 0, sizeof(hints));
  55     hints.ai_flags = AI_CANONNAME;
  56     hints.ai_family = PF_UNSPEC;
  57
  58     if (getaddrinfo(q, NULL, &hints, &res) == 0) {
  59         strncpy (buffer, res->ai_canonname, sizeof(buffer));
  60         buffer[sizeof(buffer) - 1] = '\0';
  61         freeaddrinfo(res);
  62         return buffer;
  63     }
  64     if (hosts.h_name || init_hs ()) {
  65         for (h = hosts.h_next; h; h = h->h_next)
  66             if (!mh_strcasecmp (h->h_name, q)) {
  67                 return h->h_name;
  68             } else {
  69                 for (r = h->h_aliases; *r; r++)
  70                     if (!mh_strcasecmp (*r, q))
  71                         return h->h_name;
  72             }
  73     }
  74
  75     strncpy (buffer, site, sizeof(buffer));
  76     return buffer;
  77 }
  78
  79 /*
  80  * Use hostable as an exception file for those hosts that aren't
  81  * on the Internet (listed in /etc/hosts).  These are usually
  82  * PhoneNet and UUCP sites.
  83  */
  84
  85 #define NALIASES 50
  86
  87 static int
  88 init_hs (void)
  89 {
  90     unsigned char  *cp;
  91     char *dp, **q, **r;
  92     char buffer[BUFSIZ], *aliases[NALIASES];
  93     register struct host *h;
  94     register FILE  *fp;
  95
  96     if ((fp = fopen (hostable, "r")) == NULL)
  97         return 0;
  98
  99     h = &hosts;
 100     while (fgets (buffer, sizeof(buffer), fp) != NULL) {
 101         if ((cp = strchr(buffer, '#')))
 102             *cp = 0;
 103         if ((cp = strchr(buffer, '\n')))
 104             *cp = 0;
 105         for (cp = buffer; *cp; cp++)
 106             if (isspace (*cp))
 107                 *cp = ' ';
 108         for (cp = buffer; isspace (*cp); cp++)
 109             continue;
 110         if (*cp == 0)
 111             continue;
 112
 113         q = aliases;
 114         if ((cp = strchr(dp = cp, ' '))) {
 115             *cp = 0;
 116             for (cp++; *cp; cp++) {
 117                 while (isspace (*cp))
 118                     cp++;
 119                 if (*cp == 0)
 120                     break;
 121                 if ((cp = strchr(*q++ = cp, ' ')))
 122                     *cp = 0;
 123                 else
 124                     break;
 125                 if (q >= aliases + NALIASES)
 126                     break;
 127             }
 128         }
 129
 130         *q = 0;
 131
 132         h->h_next = (struct host *) calloc (1, sizeof(*h));
 133         h = h->h_next;
 134         h->h_name = getcpy (dp);
 135         r = h->h_aliases =
 136                 (char **) calloc ((size_t) (q - aliases + 1), sizeof(*q));
 137         for (q = aliases; *q; q++)
 138             *r++ = getcpy (*q);
 139         *r = 0;
 140     }
 141
 142     fclose (fp);
 143     return 1;
 144 }