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 1.6 2004/01/20 00:54:09 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                 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