diplodocus.org Git - nmh/blob - mts/sendmail/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 #ifndef BIND
  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     strncpy (buffer, site, sizeof(buffer));
  68     return buffer;
  69 }
  70
  71 /*
  72  * Use hostable as an exception file for those hosts that aren't
  73  * on the Internet (listed in /etc/hosts).  These are usually
  74  * PhoneNet and UUCP sites.
  75  */
  76
  77 #define NALIASES 50
  78
  79 static int
  80 init_hs (void)
  81 {
  82     char  *cp, *dp, **q, **r;
  83     char buffer[BUFSIZ], *aliases[NALIASES];
  84     register struct host *h;
  85     register FILE  *fp;
  86
  87     if ((fp = fopen (hostable, "r")) == NULL)
  88         return 0;
  89
  90     h = &hosts;
  91     while (fgets (buffer, sizeof(buffer), fp) != NULL) {
  92         if ((cp = strchr(buffer, '#')))
  93             *cp = 0;
  94         if ((cp = strchr(buffer, '\n')))
  95             *cp = 0;
  96         for (cp = buffer; *cp; cp++)
  97             if (isspace (*cp))
  98                 *cp = ' ';
  99         for (cp = buffer; isspace (*cp); cp++)
 100             continue;
 101         if (*cp == 0)
 102             continue;
 103
 104         q = aliases;
 105         if ((cp = strchr(dp = cp, ' '))) {
 106             *cp = 0;
 107             for (cp++; *cp; cp++) {
 108                 while (isspace (*cp))
 109                     cp++;
 110                 if (*cp == 0)
 111                     break;
 112                 if ((cp = strchr(*q++ = cp, ' ')))
 113                     *cp = 0;
 114                 else
 115                     break;
 116                 if (q >= aliases + NALIASES)
 117                     break;
 118             }
 119         }
 120
 121         *q = 0;
 122
 123         h->h_next = (struct host *) calloc (1, sizeof(*h));
 124         h = h->h_next;
 125         h->h_name = getcpy (dp);
 126         r = h->h_aliases =
 127                 (char **) calloc ((size_t) (q - aliases + 1), sizeof(*q));
 128         for (q = aliases; *q; q++)
 129             *r++ = getcpy (*q);
 130         *r = 0;
 131     }
 132
 133     fclose (fp);
 134     return 1;
 135 }