Add the -r option to set the hostname based on a reverse lookup of an IP
[dragonfly.git] / bin / hostname / hostname.c
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 1.5 2004/01/06 08:29:34 dillon 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;
111         struct hostent *hst;
112         struct in_addr ia;
113         struct in6_addr ia6;
114
115         int mib[6];
116         int 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
283                 if (h_errno == NETDB_SUCCESS) {
284                         if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
285                                 errx(1, "sethostname");
286                 } else if (h_errno == HOST_NOT_FOUND) {
287                         errx(1,"hostname not found");
288                 } else {
289                         errx(1,"gethostbyaddr");
290                 }
291
292                 if (idx == 0) {
293                         errx(1,"interface not found");
294                 }
295         } else if (rflag) {
296                 ret = inet_pton(AF_INET, srflag, &ia);
297                 if (ret != 1) {
298                         // check IPV6
299                         ret = inet_pton(AF_INET6, srflag, &ia6);
300
301                         if (ret != 1) {
302                                 free(srflag);
303                                 errx(1, "invalid ip address");
304                         }
305
306                         flag6 = 1;
307                 }
308                 
309                 if (flag6 == 1) 
310                         hst = gethostbyaddr((const char*)&ia6, sizeof(ia6), AF_INET6);
311                 else
312                         hst = gethostbyaddr((const char*)&ia, sizeof(ia), AF_INET);
313                 if (!hst) {
314                         free(srflag);
315                         if(h_errno == HOST_NOT_FOUND) 
316                                 errx(1,"host not found\n");
317                 }
318
319                 if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
320                         err(1, "sethostname");
321         } else if (*argv) {
322                 if (sethostname(*argv, (int)strlen(*argv)))
323                         err(1, "sethostname");
324         } else {
325                 if (gethostname(hostname, (int)sizeof(hostname)))
326                         err(1, "gethostname");
327                 if (sflag && (p = strchr(hostname, '.')))
328                         *p = '\0';
329                 (void)printf("%s\n", hostname);
330         }
331         exit(0);
332 }
333
334 static void
335 usage(void)
336 {
337         fprintf(stderr, "usage: hostname [-s] [name-of-host |"
338                         " -r ip-address | -i interface [-4 | -6]]\n");
339         exit(1);
340 }
341