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  */
  37
  38 #include <sys/param.h>
  39 #include <sys/ioctl.h>
  40 #include <sys/socket.h>
  41 #include <sys/sysctl.h>
  42 #include <sys/module.h>
  43 #include <sys/linker.h>
  44
  45 #include <net/ethernet.h>
  46 #include <net/if.h>
  47 #include <net/if_var.h>
  48 #include <net/if_dl.h>
  49 #include <net/if_types.h>
  50 #include <net/route.h>
  51 #include <netinet/in.h>
  52
  53 #include <err.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <unistd.h>
  58
  59 #include <netdb.h>
  60 #include <sys/types.h>
  61 #include <arpa/inet.h>
  62
  63 #include <errno.h>
  64
  65 #define HST_IF    (1 << 0)
  66 #define HST_IF_V6 (1 << 1)
  67 #define HST_IF_V4 (1 << 2)
  68
  69
  70
  71 /*
  72  * Expand the compacted form of addresses as returned via the
  73  * configuration read via sysctl().
  74  * Lifted from getifaddrs(3)
  75  */
  76
  77 static void rt_xaddrs(caddr_t, caddr_t, struct rt_addrinfo *);
  78 static void usage (void);
  79
  80 #define ROUNDUP(a) \
  81         ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
  82 #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
  83
  84 static
  85 void
  86 rt_xaddrs(caddr_t cp, caddr_t cplim, struct rt_addrinfo *rtinfo)
  87 {
  88         struct sockaddr *sa;
  89         int i;
  90
  91         memset(rtinfo->rti_info, 0, sizeof(rtinfo->rti_info));
  92         for (i = 0; (i < RTAX_MAX) && (cp < cplim); i++) {
  93                 if ((rtinfo->rti_addrs & (1 << i)) == 0)
  94                         continue;
  95                 rtinfo->rti_info[i] = sa = (struct sockaddr *)cp;
  96                 ADVANCE(cp, sa);
  97         }
  98 }
  99
 100 int
 101 main(int argc, char **argv)
 102 {
 103         int ch, sflag, rflag, ret, flag6, iflag;
 104         int silen = 0;
 105         char hostname[MAXHOSTNAMELEN];
 106         char *srflag, *siflag;
 107         struct hostent *hst;
 108         struct in_addr ia;
 109         struct in6_addr ia6;
 110
 111         int mib[6];
 112         size_t needed;
 113         char *buf, *next, *p;
 114         int idx;
 115         struct sockaddr_dl *sdl;
 116         struct rt_msghdr *rtm;
 117         struct if_msghdr *ifm;
 118         struct ifa_msghdr *ifam;
 119         struct rt_addrinfo info;
 120         struct sockaddr_in *sai;
 121         struct sockaddr_in6 *sai6;
 122
 123         srflag = NULL;
 124         siflag = NULL;
 125         iflag = sflag = rflag = 0;
 126         flag6 = 0;
 127         hst = NULL;
 128
 129         while ((ch = getopt(argc, argv, "46i:r:s")) != -1) {
 130                 switch (ch) {
 131                 case '4':
 132                         iflag |= HST_IF_V4;
 133                         break;
 134                 case '6':
 135                         iflag |= HST_IF_V6;
 136                         break;
 137                 case 'i':
 138                         siflag = optarg;
 139                         silen = strlen(siflag);
 140                         iflag |= HST_IF;
 141                         break;
 142                 case 'r':
 143                         srflag = optarg;
 144                         rflag = 1;
 145                         break;
 146                 case 's':
 147                         sflag = 1;
 148                         break;
 149                 default:
 150                         usage();
 151                 }
 152         }
 153         argc -= optind;
 154         argv += optind;
 155
 156         if (argc > 1)
 157                 usage();
 158
 159         if (iflag && *argv)
 160                 usage();
 161
 162         if (rflag && *argv)
 163                 usage();
 164
 165         if (rflag && (iflag & HST_IF))
 166                 usage();
 167
 168         if ((iflag & HST_IF_V6) && (iflag & HST_IF_V4))
 169                 usage();
 170
 171         if (!(iflag & HST_IF) && ((iflag & HST_IF_V6)||iflag & HST_IF_V4))
 172                 usage();
 173
 174         if (iflag & HST_IF) {
 175                 mib[0] = CTL_NET;
 176                 mib[1] = PF_ROUTE;
 177                 mib[2] = 0;
 178                 mib[3] = 0;
 179                 mib[4] = NET_RT_IFLIST;
 180                 mib[5] = 0;
 181
 182                 idx = 0;
 183                 needed = 1;
 184
 185                 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
 186                         err(1, "sysctl: iflist-sysctl-estimate");
 187                 if ((buf = malloc(needed)) == NULL)
 188                         err(1, "malloc failed");
 189                 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
 190                         err(1, "sysctl: retrieval of interface table");
 191
 192                 for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
 193                         rtm = (struct rt_msghdr *)(void *)next;
 194                         if (rtm->rtm_version != RTM_VERSION)
 195                                 continue;
 196                         switch (rtm->rtm_type) {
 197                         case RTM_IFINFO:
 198                                 ifm = (struct if_msghdr *)(void *)rtm;
 199
 200                                 if ((ifm->ifm_addrs & RTA_IFP) == 0)
 201                                         break;
 202                                 sdl = (struct sockaddr_dl *)(ifm + 1);
 203                                 if (silen != sdl->sdl_nlen)
 204                                         break;
 205                                 if (!strncmp(siflag, sdl->sdl_data, silen)) {
 206                                         idx = ifm->ifm_index;
 207                                 }
 208                                 break;
 209                         case RTM_NEWADDR:
 210                                 ifam = (struct ifa_msghdr *)(void *)rtm;
 211
 212                                 if (ifam->ifam_index == idx) {
 213                                         info.rti_addrs = ifam->ifam_addrs;
 214                                         rt_xaddrs((char *)(ifam + 1),
 215                                                 ifam->ifam_msglen + (char *)ifam, &info);
 216                                         sai = (struct sockaddr_in *)info.rti_info[RTAX_IFA];
 217
 218                                         if (iflag & HST_IF_V6) {
 219                                                 if (sai->sin_family == AF_INET6) {
 220                                                         sai6 = (struct sockaddr_in6 *)info.rti_info[RTAX_IFA];
 221                                                         hst = gethostbyaddr(&sai6->sin6_addr,
 222                                                                         sizeof(sai6->sin6_addr),AF_INET6);
 223
 224                                                         if (h_errno == NETDB_SUCCESS) {
 225                                                                 next = buf + needed;
 226                                                                 continue;
 227                                                         }
 228                                                 }
 229                                         } else {
 230                                                 if ((sai->sin_family == AF_INET)) {
 231
 232                                                         hst = gethostbyaddr(&sai->sin_addr,
 233                                                                         sizeof(sai->sin_addr),AF_INET);
 234
 235                                                         if (h_errno == NETDB_SUCCESS) {
 236                                                                 next = buf + needed;
 237                                                                 continue;
 238                                                         }
 239                                                 }
 240                                         }
 241                                 }
 242                                 break;
 243                         } /* switch */
 244                 } /* loop */
 245
 246                 free(buf);
 247
 248                 if (idx == 0)
 249                         errx(1,"interface not found");
 250                 if (hst == NULL)
 251                         errx(1, "ip not found on interface");
 252
 253                 if (h_errno == NETDB_SUCCESS) {
 254                         if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
 255                                 err(1, "sethostname");
 256                 } else if (h_errno == HOST_NOT_FOUND) {
 257                         errx(1,"hostname not found");
 258                 } else {
 259                         herror("gethostbyaddr");
 260                         exit(1);
 261                 }
 262         } else if (rflag) {
 263                 ret = inet_pton(AF_INET, srflag, &ia);
 264                 if (ret != 1) {
 265                         /* check IPV6 */
 266                         ret = inet_pton(AF_INET6, srflag, &ia6);
 267
 268                         if (ret != 1) {
 269                                 errx(1, "invalid ip address");
 270                         }
 271
 272                         flag6 = 1;
 273                 }
 274
 275                 if (flag6 == 1)
 276                         hst = gethostbyaddr(&ia6, sizeof(ia6), AF_INET6);
 277                 else
 278                         hst = gethostbyaddr(&ia, sizeof(ia), AF_INET);
 279                 if (!hst) {
 280                         if (h_errno == HOST_NOT_FOUND)
 281                                 errx(1,"host not found\n");
 282                 }
 283
 284                 if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
 285                         err(1, "sethostname");
 286         } else if (*argv) {
 287                 if (sethostname(*argv, (int)strlen(*argv)))
 288                         err(1, "sethostname");
 289         } else {
 290                 if (gethostname(hostname, (int)sizeof(hostname)))
 291                         err(1, "gethostname");
 292                 if (sflag && (p = strchr(hostname, '.')))
 293                         *p = '\0';
 294                 printf("%s\n", hostname);
 295         }
 296         exit(0);
 297 }
 298
 299 static void
 300 usage(void)
 301 {
 302         fprintf(stderr, "usage: hostname [-s] [name-of-host |"
 303                         " -r ip-address | -i interface [-4 | -6]]\n");
 304         exit(1);
 305 }
 306