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 1.12 2004/11/07 20:54:51 eirikn 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         int silen = 0;
 110         char hostname[MAXHOSTNAMELEN];
 111         char *srflag, *siflag;
 112         struct hostent *hst;
 113         struct in_addr ia;
 114         struct in6_addr ia6;
 115
 116         int mib[6];
 117         size_t needed;
 118         char *buf,*lim,*next,*p;
 119         int idx;
 120         struct sockaddr_dl *sdl;
 121         struct rt_msghdr *rtm;
 122         struct if_msghdr *ifm;
 123         struct ifa_msghdr *ifam;
 124         struct rt_addrinfo info;
 125         struct sockaddr_in *sai;
 126         struct sockaddr_in6 *sai6;
 127
 128         srflag = NULL;
 129         siflag = NULL;
 130         iflag = sflag = rflag = 0;
 131         flag6 = 0;
 132         hst = NULL;
 133
 134         while ((ch = getopt(argc, argv, "46i:r:s")) != -1) {
 135                 switch (ch) {
 136                 case '4':
 137                         iflag |= HST_IF_V4;
 138                         break;
 139                 case '6':
 140                         iflag |= HST_IF_V6;
 141                         break;
 142                 case 'i':
 143                         siflag = strdup(optarg);
 144                         silen = strlen(siflag);
 145                         iflag |= HST_IF;
 146                         break;
 147                 case 'r':
 148                         srflag = strdup(optarg);
 149                         rflag = 1;
 150                         break;
 151                 case 's':
 152                         sflag = 1;
 153                         break;
 154                 case '?':
 155                 default:
 156                         usage();
 157                 }
 158         }
 159         argc -= optind;
 160         argv += optind;
 161
 162         if (argc > 1)
 163                 usage();
 164
 165         if (iflag && *argv)
 166                 usage();
 167
 168         if (rflag && *argv)
 169                 usage();
 170
 171         if (rflag && (iflag & HST_IF))
 172                 usage();
 173
 174         if ((iflag & HST_IF_V6) && (iflag & HST_IF_V4))
 175                 usage();
 176
 177         if (!(iflag & HST_IF) && ((iflag & HST_IF_V6)||iflag & HST_IF_V4))
 178                 usage();
 179
 180         if (iflag & HST_IF) {
 181                 mib[0] = CTL_NET;
 182                 mib[1] = PF_ROUTE;
 183                 mib[2] = 0;
 184                 mib[3] = 0;
 185                 mib[4] = NET_RT_IFLIST;
 186                 mib[5] = 0;
 187
 188                 idx = 0;
 189                 needed = 1;
 190
 191                 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
 192                         errx(1, "iflist-sysctl-estimate:%i",errno);
 193                 if ((buf = malloc(needed)) == NULL)
 194                         errx(1, "malloc");
 195                 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
 196                         errx(1, "actual retrieval of interface table");
 197
 198                 lim = buf + needed;
 199
 200                 for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
 201                         rtm = (struct rt_msghdr *)(void *)next;
 202                         if (rtm->rtm_version != RTM_VERSION)
 203                                 continue;
 204                         switch (rtm->rtm_type) {
 205                         case RTM_IFINFO:
 206                                 ifm = (struct if_msghdr *)(void *)rtm;
 207
 208                                 if ((ifm->ifm_addrs & RTA_IFP) == 0)
 209                                         break;
 210                                 sdl = (struct sockaddr_dl *)(ifm + 1);
 211                                 if (silen != sdl->sdl_nlen)
 212                                         break;
 213                                 if (!strncmp(siflag, sdl->sdl_data, silen)) {
 214                                         idx = ifm->ifm_index;
 215                                 }
 216                                 break;
 217                         case RTM_NEWADDR:
 218                                 ifam = (struct ifa_msghdr *)(void *)rtm;
 219
 220                                 if (ifam->ifam_index == idx) {
 221                                         info.rti_addrs = ifam->ifam_addrs;
 222                                         rt_xaddrs((char *)(ifam + 1),
 223                                                 ifam->ifam_msglen + (char *)ifam, &info);
 224                                         sai = (struct sockaddr_in *)info.rti_info[RTAX_IFA];
 225
 226                                         if (iflag & HST_IF_V6) {
 227                                                 if (sai->sin_family == AF_INET6) {
 228                                                         sai6 = (struct sockaddr_in6 *)info.rti_info[RTAX_IFA];
 229                                                         hst = gethostbyaddr((const char*)&sai6->sin6_addr,
 230                                                                         sizeof(sai6->sin6_addr),AF_INET6);
 231
 232                                                         if (h_errno == NETDB_SUCCESS) {
 233                                                                 next = buf + needed;
 234                                                                 continue;
 235                                                         }
 236                                                 }
 237                                         } else {
 238                                                 if ((sai->sin_family == AF_INET)) {
 239
 240                                                         hst = gethostbyaddr((const char*)&sai->sin_addr,
 241                                                                         sizeof(sai->sin_addr),AF_INET);
 242
 243                                                         if (h_errno == NETDB_SUCCESS) {
 244                                                                 next = buf + needed;
 245                                                                 continue;
 246                                                         }
 247                                                 }
 248                                         }
 249                                 }
 250                                 break;
 251                         } /* switch */
 252                 } /* loop */
 253
 254                 free(buf);
 255
 256                 if (idx == 0)
 257                         errx(1,"interface not found");
 258                 if (hst == NULL)
 259                         errx(1, "ip not found on interface");
 260
 261                 if (h_errno == NETDB_SUCCESS) {
 262                         if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
 263                                 errx(1, "sethostname");
 264                 } else if (h_errno == HOST_NOT_FOUND) {
 265                         errx(1,"hostname not found");
 266                 } else {
 267                         errx(1,"gethostbyaddr");
 268                 }
 269         } else if (rflag) {
 270                 ret = inet_pton(AF_INET, srflag, &ia);
 271                 if (ret != 1) {
 272                         /* check IPV6 */
 273                         ret = inet_pton(AF_INET6, srflag, &ia6);
 274
 275                         if (ret != 1) {
 276                                 errx(1, "invalid ip address");
 277                         }
 278
 279                         flag6 = 1;
 280                 }
 281
 282                 if (flag6 == 1)
 283                         hst = gethostbyaddr((const char*)&ia6, sizeof(ia6), AF_INET6);
 284                 else
 285                         hst = gethostbyaddr((const char*)&ia, sizeof(ia), AF_INET);
 286                 if (!hst) {
 287                         if (h_errno == HOST_NOT_FOUND)
 288                                 errx(1,"host not found\n");
 289                 }
 290
 291                 if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
 292                         err(1, "sethostname");
 293         } else if (*argv) {
 294                 if (sethostname(*argv, (int)strlen(*argv)))
 295                         err(1, "sethostname");
 296         } else {
 297                 if (gethostname(hostname, (int)sizeof(hostname)))
 298                         err(1, "gethostname");
 299                 if (sflag && (p = strchr(hostname, '.')))
 300                         *p = '\0';
 301                 printf("%s\n", hostname);
 302         }
 303         exit(0);
 304 }
 305
 306 static void
 307 usage(void)
 308 {
 309         fprintf(stderr, "usage: hostname [-s] [name-of-host |"
 310                         " -r ip-address | -i interface [-4 | -6]]\n");
 311         exit(1);
 312 }
 313