1 /*	gethostnamadr.c	4.6	85/01/10	*/
2 
3 #include <stdio.h>
4 #include <netdb.h>
5 #include <sys/file.h>
6 #include <ndbm.h>
7 
8 #define	MAXALIASES	35
9 
10 static char HOSTDB[] = "/etc/hosts";
11 DBM *_host_db = (DBM *)NULL;
12 static struct hostent host;
13 static char *host_aliases[MAXALIASES];
14 static char hostbuf[BUFSIZ+1];
15 int _host_stayopen;	/* set by sethostent(), cleared by endhostent() */
16 
17 static struct hostent *
18 fetchhost(key)
19 	datum key;
20 {
21         register char *cp, *tp, **ap;
22 	register int naliases;
23 
24         if (key.dptr == 0)
25                 return ((struct hostent *)NULL);
26 	key = dbm_fetch(_host_db, key);
27 	if (key.dptr == 0)
28                 return ((struct hostent *)NULL);
29         cp = key.dptr;
30 	tp = hostbuf;
31 	host.h_name = tp;
32 	while (*tp++ = *cp++)
33 		;
34 	naliases = *(int *)cp; cp += sizeof (int);
35 	for (ap = host_aliases; naliases > 0; naliases--) {
36 		*ap++ = tp;
37 		while (*tp++ = *cp++)
38 			;
39 	}
40 	*ap = (char *)NULL;
41 	host.h_aliases = host_aliases;
42 	bcopy(cp, (char *)&host.h_addrtype, sizeof (int));
43 	cp += sizeof (int);
44 	bcopy(cp, (char *)&host.h_length, sizeof (int));
45 	cp += sizeof (int);
46 	host.h_addr = tp;
47 	bcopy(cp, tp, host.h_length);
48         return (&host);
49 }
50 
51 struct hostent *
52 gethostbyname(nam)
53 	char *nam;
54 {
55         datum key;
56 	register struct hostent *hp;
57 
58 	if ((_host_db == (DBM *)NULL)
59 	  && ((_host_db = dbm_open(HOSTDB, O_RDONLY)) == (DBM *)NULL))
60                 return ((struct hostent *)NULL);
61         key.dptr = nam;
62         key.dsize = strlen(nam);
63 	hp = fetchhost(key);
64 	if (!_host_stayopen) {
65 		dbm_close(_host_db);
66 		_host_db = (DBM *)NULL;
67 	}
68         return (hp);
69 }
70 
71 struct hostent *
72 gethostbyaddr(addr, length)
73 	char *addr;
74 	int length;
75 {
76         datum key;
77 	register struct hostent *hp;
78 
79 	if ((_host_db == (DBM *)NULL)
80 	  && ((_host_db = dbm_open(HOSTDB, O_RDONLY)) == (DBM *)NULL))
81                 return ((struct hostent *)NULL);
82         key.dptr = addr;
83         key.dsize = length;
84 	hp = fetchhost(key);
85 	if (!_host_stayopen) {
86 		dbm_close(_host_db);
87 		_host_db = (DBM *)NULL;
88 	}
89         return (hp);
90 }
91