gethostnamadr.c revision 3070 
1/*-
2 * Copyright (c) 1994, Garrett Wollman
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26#if defined(LIBC_SCCS) && !defined(lint)
27static char sccsid[] = "@(#)$Id$";
28static char rcsid[] = "$Id$";
29#endif /* LIBC_SCCS and not lint */
30
31#include <sys/param.h>
32#include <sys/socket.h>
33#include <netinet/in.h>
34#include <arpa/inet.h>
35#include <netdb.h>
36#include <stdio.h>
37#include <ctype.h>
38#include <errno.h>
39#include <string.h>
40
41extern struct hostent * _gethostbyhtname  __P((const char *));
42extern struct hostent * _gethostbydnsname __P((const char *));
43extern struct hostent * _gethostbynisname __P((const char *));
44extern struct hostent * _gethostbyhtaddr  __P((const char *, int, int));
45extern struct hostent * _gethostbydnsaddr __P((const char *, int, int));
46extern struct hostent * _gethostbynisaddr __P((const char *, int, int));
47
48#define _PATH_HOSTCONF	"/etc/host.conf"
49
50enum service_type {
51  SERVICE_NONE = 0,
52  SERVICE_BIND,
53  SERVICE_HOSTS,
54  SERVICE_NIS };
55#define SERVICE_MAX	SERVICE_NIS
56
57static struct {
58  const char *name;
59  enum service_type type;
60} service_names[] = {
61  { "hosts", SERVICE_HOSTS },
62  { "/etc/hosts", SERVICE_HOSTS },
63  { "hosttable", SERVICE_HOSTS },
64  { "htable", SERVICE_HOSTS },
65  { "bind", SERVICE_BIND },
66  { "dns", SERVICE_BIND },
67  { "domain", SERVICE_BIND },
68  { "yp", SERVICE_NIS },
69  { "yellowpages", SERVICE_NIS },
70  { "nis", SERVICE_NIS },
71  { 0, SERVICE_NONE }
72};
73
74static enum service_type service_order[SERVICE_MAX + 1];
75static int service_done = 0;
76
77static enum service_type
78get_service_name(const char *name) {
79	int i;
80	for(i = 0; service_names[i].type != SERVICE_NONE; i++) {
81		if(!strcasecmp(name, service_names[i].name)) {
82			return service_names[i].type;
83		}
84	}
85	return SERVICE_NONE;
86}
87
88static void
89init_services()
90{
91	char *cp, buf[BUFSIZ];
92	register int cc = 0;
93	FILE *fd;
94
95	if ((fd = (FILE *)fopen(_PATH_HOSTCONF, "r")) == NULL) {
96				/* make some assumptions */
97		service_order[0] = SERVICE_BIND;
98		service_order[1] = SERVICE_HOSTS;
99		service_order[2] = SERVICE_NONE;
100	} else {
101		while (fgets(buf, BUFSIZ, fd) != NULL && cc < SERVICE_MAX) {
102			if(buf[0] == '#')
103				continue;
104
105			cp = strtok(buf, "\n \t,:;");
106			do {
107				if(!isalpha(cp[0])) continue;
108				service_order[cc] = get_service_name(buf);
109				if(service_order[cc] != SERVICE_NONE)
110					cc++;
111			} while((cp = strtok((char *)0, "\n \t,:;"))
112				&& (cc < SERVICE_MAX));
113		}
114		service_order[cc] = SERVICE_NONE;
115		fclose(fd);
116	}
117	service_done = 1;
118}
119
120struct hostent *
121gethostbyname(const char *name)
122{
123	struct hostent *hp = 0;
124	int nserv = 0;
125
126	if (!service_done)
127		init_services();
128
129	while (!hp) {
130		switch (service_order[nserv]) {
131		      case SERVICE_NONE:
132			return NULL;
133		      case SERVICE_HOSTS:
134			hp = _gethostbyhtname(name);
135			break;
136		      case SERVICE_BIND:
137			hp = _gethostbydnsname(name);
138			break;
139		      case SERVICE_NIS:
140			hp = _gethostbynisname(name);
141			break;
142		}
143		nserv++;
144	}
145	return hp;
146}
147
148struct hostent *
149gethostbyaddr(const char *addr, int len, int type)
150{
151	struct hostent *hp = 0;
152	int nserv = 0;
153
154	if (!service_done)
155		init_services();
156
157	while (!hp) {
158		switch (service_order[nserv]) {
159		      case SERVICE_NONE:
160			return 0;
161		      case SERVICE_HOSTS:
162			hp = _gethostbyhtaddr(addr, len, type);
163			break;
164		      case SERVICE_BIND:
165			hp = _gethostbydnsaddr(addr, len, type);
166			break;
167		      case SERVICE_NIS:
168			hp = _gethostbynisaddr(addr, len, type);
169			break;
170		}
171		nserv++;
172	}
173	return hp;
174}
175
176void
177sethostent(stayopen)
178	int stayopen;
179{
180	_sethosthtent(stayopen);
181	_sethostdnsent(stayopen);
182}
183
184void
185endhostent()
186{
187	_endhosthtent();
188	_endhostdnsent();
189}
190