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