xref: /dragonfly/bin/hostname/hostname.c (revision 1ab20d67) 
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. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * @(#) Copyright (c) 1988, 1993 The Regents of the University of California.  All rights reserved.
34  * @(#)hostname.c	8.1 (Berkeley) 5/31/93
35  * $FreeBSD: src/bin/hostname/hostname.c,v 1.10.2.1 2001/08/01 02:40:23 obrien Exp $
36  * $DragonFly: src/bin/hostname/hostname.c,v 1.7 2004/03/19 17:17:46 cpressey Exp $
37  */
38 
39 #include <sys/param.h>
40 #include <sys/ioctl.h>
41 #include <sys/socket.h>
42 #include <sys/sysctl.h>
43 #include <sys/time.h>
44 #include <sys/module.h>
45 #include <sys/linker.h>
46 
47 
48 #include <net/ethernet.h>
49 #include <net/if.h>
50 #include <net/if_var.h>
51 #include <net/if_dl.h>
52 #include <net/if_types.h>
53 #include <net/route.h>
54 #include <netinet/in.h>
55 
56 
57 #include <err.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <unistd.h>
62 
63 #include <netdb.h>
64 #include <sys/types.h>
65 #include <netinet/in.h>
66 #include <arpa/inet.h>
67 
68 #include <errno.h>
69 
70 #define HST_IF    (1 << 0)
71 #define HST_IF_V6 (1 << 1)
72 #define HST_IF_V4 (1 << 2)
73 
74 
75 
76 /*
77  * Expand the compacted form of addresses as returned via the
78  * configuration read via sysctl().
79  * Lifted from getifaddrs(3)
80  */
81 
82 static void rt_xaddrs(caddr_t, caddr_t, struct rt_addrinfo *);
83 static void usage (void);
84 
85 #define ROUNDUP(a) \
86 	((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
87 #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
88 
89 static
90 void
91 rt_xaddrs(caddr_t cp, caddr_t cplim, struct rt_addrinfo *rtinfo)
92 {
93 	struct sockaddr *sa;
94 	int i;
95 
96 	memset(rtinfo->rti_info, 0, sizeof(rtinfo->rti_info));
97 	for (i = 0; (i < RTAX_MAX) && (cp < cplim); i++) {
98 		if ((rtinfo->rti_addrs & (1 << i)) == 0)
99 			continue;
100 		rtinfo->rti_info[i] = sa = (struct sockaddr *)cp;
101 		ADVANCE(cp, sa);
102 	}
103 }
104 
105 int
106 main(int argc, char **argv)
107 {
108 	int ch,sflag,rflag,ret,flag6,iflag;
109 	char hostname[MAXHOSTNAMELEN];
110 	char *srflag, *siflag = NULL;
111 	struct hostent *hst;
112 	struct in_addr ia;
113 	struct in6_addr ia6;
114 
115 	int mib[6];
116 	size_t needed;
117 	char *buf,*lim,*next,*p;
118 	int idx;
119 	struct sockaddr_dl *sdl;
120 	struct rt_msghdr *rtm;
121 	struct if_msghdr *ifm;
122 	struct ifa_msghdr *ifam;
123 	struct rt_addrinfo info;
124 	struct sockaddr_in *sai;
125 	struct sockaddr_in6 *sai6;
126 
127 	srflag = NULL;
128 	iflag = sflag = rflag = 0;
129 	flag6 = 0;
130 	hst = NULL;
131 
132 	while ((ch = getopt(argc, argv, "46i:r:s")) != -1) {
133 		switch (ch) {
134 		case '4':
135 			iflag |= HST_IF_V4;
136 			break;
137 		case '6':
138 			iflag |= HST_IF_V6;
139 			break;
140 		case 'i':
141 			siflag = (char*)calloc(1,sizeof(char) * (strlen((char*)optarg)+1));
142 			if (siflag) {
143 				iflag |= HST_IF;
144 				strlcpy(siflag, (char*)optarg, strlen((char*)optarg)+1);
145 			} else {
146 				errx(1, "malloc");
147 			}
148 			break;
149 		case 'r':
150 			srflag = (char*)calloc(1,sizeof(char) * (strlen((char*)optarg)+1));
151 			if (srflag) {
152 				rflag = 1;
153 				strlcpy(srflag, (char*)optarg, strlen((char*)optarg)+1);
154 			} else {
155 				errx(1, "malloc");
156 			}
157 			break;
158 		case 's':
159 			sflag = 1;
160 			break;
161 		case '?':
162 		default:
163 			usage();
164 		}
165 	}
166 	argc -= optind;
167 	argv += optind;
168 
169 	if (argc > 1)
170 		usage();
171 
172 	if (iflag && *argv) {
173 		free(siflag);
174 		usage();
175 	}
176 
177 	if (rflag && *argv) {
178 		free(srflag);
179 		usage();
180 	}
181 
182 	if (rflag && (iflag & HST_IF)) {
183 		usage();
184 		free(srflag);
185 		free(siflag);
186 	}
187 
188 	if ((iflag & HST_IF_V6) && (iflag & HST_IF_V4)) {
189 		free(siflag);
190 		usage();
191 	}
192 
193 	if (!(iflag & HST_IF) && ((iflag & HST_IF_V6)||iflag & HST_IF_V4)) {
194 		free(siflag);
195 		usage();
196 	}
197 
198 	if (iflag & HST_IF) {
199 		mib[0] = CTL_NET;
200 		mib[1] = PF_ROUTE;
201 		mib[2] = 0;
202 		mib[3] = 0;
203 		mib[4] = NET_RT_IFLIST;
204 		mib[5] = 0;
205 
206 		idx = 0;
207 		needed = 1;
208 
209 		if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) {
210 			free(siflag);
211 			errx(1, "iflist-sysctl-estimate:%i",errno);
212 		}
213 		if ((buf = malloc(needed)) == NULL) {
214 			free(siflag);
215 			errx(1, "malloc");
216 		}
217 		if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
218 			free(siflag);
219 			errx(1, "actual retrieval of interface table");
220 		}
221 
222 		lim = buf + needed;
223 
224 		for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
225 			rtm = (struct rt_msghdr *)(void *)next;
226 			if (rtm->rtm_version != RTM_VERSION)
227 				continue;
228 			switch (rtm->rtm_type) {
229 			case RTM_IFINFO:
230 				ifm = (struct if_msghdr *)(void *)rtm;
231 
232 				if (ifm->ifm_addrs & RTA_IFP) {
233 					sdl = (struct sockaddr_dl *)(ifm+1);
234 					if (strcmp(siflag,sdl->sdl_data) == 0) {
235 						idx = ifm->ifm_index;
236 					}
237 				}
238 				break;
239 			case RTM_NEWADDR:
240 				ifam = (struct ifa_msghdr *)(void *)rtm;
241 
242 				if (ifam->ifam_index == idx) {
243 					info.rti_addrs = ifam->ifam_addrs;
244 					rt_xaddrs((char *)(ifam + 1),
245 						ifam->ifam_msglen + (char *)ifam, &info);
246 					sai = (struct sockaddr_in *)info.rti_info[RTAX_IFA];
247 
248 					if (iflag & HST_IF_V6) {
249 						if (sai->sin_family == AF_INET6) {
250 							sai6 = (struct sockaddr_in6 *)info.rti_info[RTAX_IFA];
251 							hst = gethostbyaddr((const char*)&sai6->sin6_addr,
252 									sizeof(sai6->sin6_addr),AF_INET6);
253 
254 							if (h_errno == NETDB_SUCCESS) {
255 								next = buf + needed;
256 								continue;
257 							}
258 						}
259 					} else {
260 						if ((sai->sin_family == AF_INET)) {
261 
262 							hst = gethostbyaddr((const char*)&sai->sin_addr,
263 									sizeof(sai->sin_addr),AF_INET);
264 
265 							if (h_errno == NETDB_SUCCESS) {
266 								next = buf + needed;
267 								continue;
268 							}
269 						}
270 					}
271 				}
272 				break;
273 			} /* switch */
274 		} /* loop */
275 
276 		free(buf);
277 		free(siflag);
278 
279 		if (idx == 0) {
280 			errx(1,"interface not found");
281 		}
282 		if (hst == NULL) {
283 			errx(1, "ip not found on interface");
284 		}
285 
286 		if (h_errno == NETDB_SUCCESS) {
287 			if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
288 				errx(1, "sethostname");
289 		} else if (h_errno == HOST_NOT_FOUND) {
290 			errx(1,"hostname not found");
291 		} else {
292 			errx(1,"gethostbyaddr");
293 		}
294 	} else if (rflag) {
295 		ret = inet_pton(AF_INET, srflag, &ia);
296 		if (ret != 1) {
297 			/* check IPV6 */
298 			ret = inet_pton(AF_INET6, srflag, &ia6);
299 
300 			if (ret != 1) {
301 				free(srflag);
302 				errx(1, "invalid ip address");
303 			}
304 
305 			flag6 = 1;
306 		}
307 
308 		if (flag6 == 1)
309 			hst = gethostbyaddr((const char*)&ia6, sizeof(ia6), AF_INET6);
310 		else
311 			hst = gethostbyaddr((const char*)&ia, sizeof(ia), AF_INET);
312 		if (!hst) {
313 			free(srflag);
314 			if(h_errno == HOST_NOT_FOUND)
315 				errx(1,"host not found\n");
316 		}
317 
318 		if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
319 			err(1, "sethostname");
320 	} else if (*argv) {
321 		if (sethostname(*argv, (int)strlen(*argv)))
322 			err(1, "sethostname");
323 	} else {
324 		if (gethostname(hostname, (int)sizeof(hostname)))
325 			err(1, "gethostname");
326 		if (sflag && (p = strchr(hostname, '.')))
327 			*p = '\0';
328 		(void)printf("%s\n", hostname);
329 	}
330 	exit(0);
331 }
332 
333 static void
334 usage(void)
335 {
336 	fprintf(stderr, "usage: hostname [-s] [name-of-host |"
337 			" -r ip-address | -i interface [-4 | -6]]\n");
338 	exit(1);
339 }
340 
341