bin/hostname/hostname.c

   1 /* $NetBSD: hostname.c,v 1.20 2013/07/19 15:53:00 christos Exp $ */
   2
   3 /*
   4  * Copyright (c) 1988, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #ifndef lint
  34 __COPYRIGHT("@(#) Copyright (c) 1988, 1993\
  35  The Regents of the University of California.  All rights reserved.");
  36 #endif /* not lint */
  37
  38 #ifndef lint
  39 #if 0
  40 static char sccsid[] = "@(#)hostname.c  8.2 (Berkeley) 4/28/95";
  41 #else
  42 __RCSID("$NetBSD: hostname.c,v 1.20 2013/07/19 15:53:00 christos Exp $");
  43 #endif
  44 #endif /* not lint */
  45
  46 #include <sys/param.h>
  47 #include <sys/socket.h>
  48
  49 #include <net/if.h>
  50 #include <netinet/in.h>
  51
  52 #include <err.h>
  53 #include <ifaddrs.h>
  54 #include <netdb.h>
  55 #include <stdio.h>
  56 #include <stdlib.h>
  57 #include <string.h>
  58 #include <unistd.h>
  59
  60 __dead static void usage(void);
  61
  62 int
  63 main(int argc, char *argv[])
  64 {
  65         int ch, Aflag, aflag, dflag, Iflag, iflag, fflag, sflag, i;
  66         char *p, hostname[MAXHOSTNAMELEN + 1];
  67         struct addrinfo hints, *ainfos, *ai;
  68         struct hostent *hent;
  69         struct ifaddrs *ifa, *ifp;
  70         struct sockaddr_in6 *sin6;
  71         char buf[MAX(MAXHOSTNAMELEN + 1, INET6_ADDRSTRLEN)];
  72
  73         setprogname(argv[0]);
  74         Aflag = aflag = dflag = Iflag = iflag = fflag = sflag = 0;
  75         while ((ch = getopt(argc, argv, "AadIifs")) != -1)
  76                 switch (ch) {
  77                 case 'A':
  78                         Aflag = 1;
  79                         break;
  80                 case 'a':
  81                         aflag = 1;
  82                         break;
  83                 case 'd':
  84                         dflag = 1;
  85                         break;
  86                 case 'I':
  87                         Iflag = 1;
  88                         break;
  89                 case 'i':
  90                         iflag = 1;
  91                         break;
  92                 case 'f':
  93                         fflag = 1;
  94                         break;
  95                 case 's':
  96                         sflag = 1;
  97                         break;
  98                 case '?':
  99                 default:
 100                         usage();
 101                 }
 102         argc -= optind;
 103         argv += optind;
 104
 105         if (argc > 1)
 106                 usage();
 107
 108         if (*argv) {
 109                 if (sethostname(*argv, strlen(*argv)))
 110                         err(1, "sethostname");
 111         } else if (Aflag || Iflag) {
 112                 if (getifaddrs(&ifa) == -1)
 113                         err(1, "getifaddrs");
 114                 for (ifp = ifa; ifp; ifp = ifp->ifa_next) {
 115                         if (ifp->ifa_addr == NULL ||
 116 #if !defined(__minix)
 117                             ifp->ifa_flags & IFF_LOOPBACK ||
 118 #endif
 119                             !(ifp->ifa_flags & IFF_UP))
 120                                 continue;
 121
 122                         switch(ifp->ifa_addr->sa_family) {
 123                         case AF_INET:
 124                                 break;
 125                         case AF_INET6:
 126                                 /* Skip link local addresses */
 127                                 sin6 = (struct sockaddr_in6 *)ifp->ifa_addr;
 128                                 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
 129                                     IN6_IS_ADDR_MC_LINKLOCAL(&sin6->sin6_addr))
 130                                         continue;
 131                                 break;
 132                         default:
 133                                 /* We only translate IPv4 or IPv6 addresses */
 134                                 continue;
 135                         }
 136                         i = getnameinfo(ifp->ifa_addr, ifp->ifa_addr->sa_len,
 137                             buf, sizeof(buf), NULL, 0,
 138                             Iflag ? NI_NUMERICHOST: NI_NAMEREQD);
 139                         if (i) {
 140                                 if (Iflag && i != EAI_NONAME)
 141                                         errx(1, "getnameinfo: %s",
 142                                             gai_strerror(i));
 143                         } else
 144                                 printf("%s\n", buf);
 145                 }
 146                 freeifaddrs(ifa);
 147         } else {
 148                 if (gethostname(hostname, sizeof(hostname)))
 149                         err(1, "gethostname");
 150                 hostname[sizeof(hostname) - 1] = '\0';
 151                 if (aflag) {
 152                         if ((hent = gethostbyname(hostname)) == NULL)
 153                                 errx(1, "gethostbyname: %s",
 154                                     hstrerror(h_errno));
 155                         for (i = 0; hent->h_aliases[i]; i++)
 156                                 printf("%s\n", hent->h_aliases[i]);
 157                 } else if (dflag || iflag || fflag) {
 158                         memset(&hints, 0, sizeof(hints));
 159                         hints.ai_family = AF_UNSPEC;
 160                         hints.ai_socktype = SOCK_DGRAM;
 161                         hints.ai_flags = AI_CANONNAME;
 162                         i = getaddrinfo(hostname, NULL, &hints, &ainfos);
 163                         if (i)
 164                                 errx(1, "getaddrinfo: %s", gai_strerror(i));
 165                         if (ainfos) {
 166                                 if (dflag) {
 167                                         if ((p = strchr(ainfos->ai_canonname,
 168                                             '.')))
 169                                                 printf("%s\n", p + 1);
 170                                 } else if (iflag) {
 171                                         for (ai = ainfos; ai; ai = ai->ai_next)
 172                                         {
 173                                                 i = getnameinfo(ai->ai_addr,
 174                                                     ai->ai_addrlen,
 175                                                     buf, sizeof(buf), NULL, 0,
 176                                                     NI_NUMERICHOST);
 177                                                 if (i)
 178                                                         errx(1,
 179                                                             "getnameinfo: %s",
 180                                                             gai_strerror(i));
 181                                                 printf("%s\n", buf);
 182                                         }
 183                                 } else {
 184                                         if (sflag &&
 185                                             (p = strchr(ainfos->ai_canonname,
 186                                             '.')))
 187                                                 *p = '\0';
 188                                         printf("%s\n", ainfos->ai_canonname);
 189                                 }
 190                                 freeaddrinfo(ainfos);
 191                         }
 192                 } else {
 193                         if (sflag && (p = strchr(hostname, '.')))
 194                                 *p = '\0';
 195                         printf("%s\n", hostname);
 196                 }
 197         }
 198         exit(0);
 199         /* NOTREACHED */
 200 }
 201
 202 static void
 203 usage(void)
 204 {
 205         (void)fprintf(stderr, "usage: %s [-AadfIis] [name-of-host]\n",
 206             getprogname());
 207         exit(1);
 208         /* NOTREACHED */
 209 }