1 /*
2 * Copyright (c) 1988, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#) Copyright (c) 1988, 1993 The Regents of the University of California. All rights reserved.
30 * @(#)hostname.c 8.1 (Berkeley) 5/31/93
31 * $FreeBSD: src/bin/hostname/hostname.c,v 1.10.2.1 2001/08/01 02:40:23 obrien Exp $
32 */
33
34 #include <sys/param.h>
35 #include <sys/ioctl.h>
36 #include <sys/socket.h>
37 #include <sys/sysctl.h>
38 #include <sys/module.h>
39 #include <sys/linker.h>
40
41 #include <net/ethernet.h>
42 #include <net/if.h>
43 #include <net/if_var.h>
44 #include <net/if_dl.h>
45 #include <net/if_types.h>
46 #include <net/route.h>
47 #include <netinet/in.h>
48
49 #include <err.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <unistd.h>
54
55 #include <netdb.h>
56 #include <sys/types.h>
57 #include <arpa/inet.h>
58
59 #include <errno.h>
60
61 #define HST_IF (1 << 0)
62 #define HST_IF_V6 (1 << 1)
63 #define HST_IF_V4 (1 << 2)
64
65 /*
66 * Expand the compacted form of addresses as returned via the
67 * configuration read via sysctl().
68 * Lifted from getifaddrs(3)
69 */
70
71 static void rt_xaddrs(caddr_t, caddr_t, struct rt_addrinfo *);
72 static void usage (void);
73
74 #ifndef RT_ROUNDUP
75 #define RT_ROUNDUP(a) \
76 ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
77 #endif
78 #ifndef RT_ADVANCE
79 #define RT_ADVANCE(x, n) (x += RT_ROUNDUP((n)->sa_len))
80 #endif
81
82 static
83 void
rt_xaddrs(caddr_t cp,caddr_t cplim,struct rt_addrinfo * rtinfo)84 rt_xaddrs(caddr_t cp, caddr_t cplim, struct rt_addrinfo *rtinfo)
85 {
86 struct sockaddr *sa;
87 int i;
88
89 memset(rtinfo->rti_info, 0, sizeof(rtinfo->rti_info));
90 for (i = 0; (i < RTAX_MAX) && (cp < cplim); i++) {
91 if ((rtinfo->rti_addrs & (1 << i)) == 0)
92 continue;
93 rtinfo->rti_info[i] = sa = (struct sockaddr *)cp;
94 RT_ADVANCE(cp, sa);
95 }
96 }
97
98 int
main(int argc,char ** argv)99 main(int argc, char **argv)
100 {
101 int ch, sflag, rflag, ret, flag6, iflag;
102 int silen = 0;
103 char hostname[MAXHOSTNAMELEN];
104 char *srflag, *siflag;
105 struct hostent *hst;
106 struct in_addr ia;
107 struct in6_addr ia6;
108
109 int mib[6];
110 size_t needed;
111 char *buf, *next, *p;
112 int idx;
113 struct sockaddr_dl *sdl;
114 struct rt_msghdr *rtm;
115 struct if_msghdr *ifm;
116 struct ifa_msghdr *ifam;
117 struct rt_addrinfo info;
118 struct sockaddr_in *sai;
119 struct sockaddr_in6 *sai6;
120
121 srflag = NULL;
122 siflag = NULL;
123 iflag = sflag = rflag = 0;
124 flag6 = 0;
125 hst = NULL;
126
127 while ((ch = getopt(argc, argv, "46fi:r:s")) != -1) {
128 switch (ch) {
129 case '4':
130 iflag |= HST_IF_V4;
131 break;
132 case '6':
133 iflag |= HST_IF_V6;
134 break;
135 case 'f':
136 /* Printing the FQDN is default. */
137 break;
138 case 'i':
139 siflag = optarg;
140 silen = strlen(siflag);
141 iflag |= HST_IF;
142 break;
143 case 'r':
144 srflag = optarg;
145 rflag = 1;
146 break;
147 case 's':
148 sflag = 1;
149 break;
150 default:
151 usage();
152 }
153 }
154 argc -= optind;
155 argv += optind;
156
157 if (argc > 1)
158 usage();
159
160 if (iflag && *argv)
161 usage();
162
163 if (rflag && *argv)
164 usage();
165
166 if (rflag && (iflag & HST_IF))
167 usage();
168
169 if ((iflag & HST_IF_V6) && (iflag & HST_IF_V4))
170 usage();
171
172 if (!(iflag & HST_IF) && ((iflag & HST_IF_V6)||iflag & HST_IF_V4))
173 usage();
174
175 if (iflag & HST_IF) {
176 mib[0] = CTL_NET;
177 mib[1] = PF_ROUTE;
178 mib[2] = 0;
179 mib[3] = 0;
180 mib[4] = NET_RT_IFLIST;
181 mib[5] = 0;
182
183 idx = 0;
184 needed = 1;
185
186 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
187 err(1, "sysctl: iflist-sysctl-estimate");
188 if ((buf = malloc(needed)) == NULL)
189 err(1, "malloc failed");
190 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
191 err(1, "sysctl: retrieval of interface table");
192
193 for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
194 rtm = (struct rt_msghdr *)(void *)next;
195 if (rtm->rtm_version != RTM_VERSION)
196 continue;
197 switch (rtm->rtm_type) {
198 case RTM_IFINFO:
199 ifm = (struct if_msghdr *)(void *)rtm;
200
201 if ((ifm->ifm_addrs & RTA_IFP) == 0)
202 break;
203 sdl = (struct sockaddr_dl *)(ifm + 1);
204 if (silen != sdl->sdl_nlen)
205 break;
206 if (!strncmp(siflag, sdl->sdl_data, silen)) {
207 idx = ifm->ifm_index;
208 }
209 break;
210 case RTM_NEWADDR:
211 ifam = (struct ifa_msghdr *)(void *)rtm;
212
213 if (ifam->ifam_index == idx) {
214 info.rti_addrs = ifam->ifam_addrs;
215 rt_xaddrs((char *)(ifam + 1),
216 ifam->ifam_msglen + (char *)ifam, &info);
217 sai = (struct sockaddr_in *)info.rti_info[RTAX_IFA];
218
219 if (iflag & HST_IF_V6) {
220 if (sai->sin_family == AF_INET6) {
221 sai6 = (struct sockaddr_in6 *)info.rti_info[RTAX_IFA];
222 hst = gethostbyaddr(&sai6->sin6_addr,
223 sizeof(sai6->sin6_addr),AF_INET6);
224
225 if (h_errno == NETDB_SUCCESS) {
226 next = buf + needed;
227 continue;
228 }
229 }
230 } else {
231 if (sai->sin_family == AF_INET) {
232
233 hst = gethostbyaddr(&sai->sin_addr,
234 sizeof(sai->sin_addr),AF_INET);
235
236 if (h_errno == NETDB_SUCCESS) {
237 next = buf + needed;
238 continue;
239 }
240 }
241 }
242 }
243 break;
244 } /* switch */
245 } /* loop */
246
247 free(buf);
248
249 if (idx == 0)
250 errx(1,"interface not found");
251 if (hst == NULL)
252 errx(1, "ip not found on interface");
253
254 if (h_errno == NETDB_SUCCESS) {
255 if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
256 err(1, "sethostname");
257 } else if (h_errno == HOST_NOT_FOUND) {
258 errx(1,"hostname not found");
259 } else {
260 herror("gethostbyaddr");
261 exit(1);
262 }
263 } else if (rflag) {
264 ret = inet_pton(AF_INET, srflag, &ia);
265 if (ret != 1) {
266 /* check IPV6 */
267 ret = inet_pton(AF_INET6, srflag, &ia6);
268
269 if (ret != 1) {
270 errx(1, "invalid ip address");
271 }
272
273 flag6 = 1;
274 }
275
276 if (flag6 == 1)
277 hst = gethostbyaddr(&ia6, sizeof(ia6), AF_INET6);
278 else
279 hst = gethostbyaddr(&ia, sizeof(ia), AF_INET);
280 if (!hst) {
281 if (h_errno == HOST_NOT_FOUND)
282 errx(1,"host not found\n");
283 }
284
285 if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
286 err(1, "sethostname");
287 } else if (*argv) {
288 if (sethostname(*argv, (int)strlen(*argv)))
289 err(1, "sethostname");
290 } else {
291 if (gethostname(hostname, (int)sizeof(hostname)))
292 err(1, "gethostname");
293 if (sflag && (p = strchr(hostname, '.')))
294 *p = '\0';
295 printf("%s\n", hostname);
296 }
297 exit(0);
298 }
299
300 static void
usage(void)301 usage(void)
302 {
303 fprintf(stderr, "usage: hostname [-s] [name-of-host |"
304 " -r ip-address | -i interface [-4 | -6]]\n");
305 exit(1);
306 }
307
308