busybox/networking/hostname.c
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   1/* vi: set sw=4 ts=4: */
   2/*
   3 * Mini hostname implementation for busybox
   4 *
   5 * Copyright (C) 1999 by Randolph Chung <tausq@debian.org>
   6 *
   7 * Adjusted by Erik Andersen <andersen@codepoet.org> to remove
   8 * use of long options and GNU getopt.  Improved the usage info.
   9 *
  10 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  11 */
  12
  13//usage:#define hostname_trivial_usage
  14//usage:       "[OPTIONS] [HOSTNAME | -F FILE]"
  15//usage:#define hostname_full_usage "\n\n"
  16//usage:       "Get or set hostname or DNS domain name\n"
  17//usage:     "\n        -s      Short"
  18//usage:     "\n        -i      Addresses for the hostname"
  19//usage:     "\n        -d      DNS domain name"
  20//usage:     "\n        -f      Fully qualified domain name"
  21//usage:     "\n        -F FILE Use FILE's content as hostname"
  22//usage:
  23//usage:#define hostname_example_usage
  24//usage:       "$ hostname\n"
  25//usage:       "sage\n"
  26//usage:
  27//usage:#define dnsdomainname_trivial_usage NOUSAGE_STR
  28//usage:#define dnsdomainname_full_usage ""
  29
  30#include "libbb.h"
  31
  32static void do_sethostname(char *s, int isfile)
  33{
  34//      if (!s)
  35//              return;
  36        if (isfile) {
  37                parser_t *parser = config_open2(s, xfopen_for_read);
  38                while (config_read(parser, &s, 1, 1, "# \t", PARSE_NORMAL & ~PARSE_GREEDY)) {
  39                        do_sethostname(s, 0);
  40                }
  41                if (ENABLE_FEATURE_CLEAN_UP)
  42                        config_close(parser);
  43        } else if (sethostname(s, strlen(s))) {
  44//              if (errno == EPERM)
  45//                      bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
  46                bb_perror_msg_and_die("sethostname");
  47        }
  48}
  49
  50/* Manpage circa 2009:
  51 *
  52 * hostname [-v] [-a] [--alias] [-d] [--domain] [-f] [--fqdn] [--long]
  53 *      [-i] [--ip-address] [-s] [--short] [-y] [--yp] [--nis]
  54 *
  55 * hostname [-v] [-F filename] [--file filename] / [hostname]
  56 *
  57 * domainname [-v] [-F filename] [--file filename]  / [name]
  58 *  { bbox: not supported }
  59 *
  60 * nodename [-v] [-F filename] [--file filename] / [name]
  61 *  { bbox: not supported }
  62 *
  63 * dnsdomainname [-v]
  64 *  { bbox: supported: Linux kernel build needs this }
  65 * nisdomainname [-v]
  66 *  { bbox: not supported }
  67 * ypdomainname [-v]
  68 *  { bbox: not supported }
  69 *
  70 * -a, --alias
  71 *  Display the alias name of the host (if used).
  72 *  { bbox: not supported }
  73 * -d, --domain
  74 *  Display the name of the DNS domain. Don't use the command
  75 *  domainname to get the DNS domain name because it will show the
  76 *  NIS domain name and not the DNS domain name. Use dnsdomainname
  77 *  instead.
  78 * -f, --fqdn, --long
  79 *  Display the FQDN (Fully Qualified Domain Name). A FQDN consists
  80 *  of a short host name and the DNS domain name. Unless you are
  81 *  using bind or NIS for host lookups you can change the FQDN and
  82 *  the DNS domain name (which is part of the FQDN) in the
  83 *  /etc/hosts file.
  84 * -i, --ip-address
  85 *  Display the IP address(es) of the host.
  86 * -s, --short
  87 *  Display the short host name. This is the host name cut at the
  88 *  first dot.
  89 * -v, --verbose
  90 *  Be verbose and tell what's going on.
  91 *  { bbox: supported but ignored }
  92 * -y, --yp, --nis
  93 *  Display the NIS domain name. If a parameter is given (or --file
  94 *  name ) then root can also set a new NIS domain.
  95 *  { bbox: not supported }
  96 * -F, --file filename
  97 *  Read the host name from the specified file. Comments (lines
  98 *  starting with a `#') are ignored.
  99 */
 100int hostname_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 101int hostname_main(int argc UNUSED_PARAM, char **argv)
 102{
 103        enum {
 104                OPT_d = 0x1,
 105                OPT_f = 0x2,
 106                OPT_i = 0x4,
 107                OPT_s = 0x8,
 108                OPT_F = 0x10,
 109                OPT_dfis = 0xf,
 110        };
 111
 112        unsigned opts;
 113        char *buf;
 114        char *hostname_str;
 115
 116#if ENABLE_LONG_OPTS
 117        applet_long_options =
 118                "domain\0"     No_argument "d"
 119                "fqdn\0"       No_argument "f"
 120        //Enable if seen in active use in some distro:
 121        //      "long\0"       No_argument "f"
 122        //      "ip-address\0" No_argument "i"
 123        //      "short\0"      No_argument "s"
 124        //      "verbose\0"    No_argument "v"
 125                "file\0"       No_argument "F"
 126                ;
 127
 128#endif
 129        /* dnsdomainname from net-tools 1.60, hostname 1.100 (2001-04-14),
 130         * supports hostname's options too (not just -v as manpage says) */
 131        opts = getopt32(argv, "dfisF:v", &hostname_str);
 132        argv += optind;
 133        buf = safe_gethostname();
 134        if (applet_name[0] == 'd') /* dnsdomainname? */
 135                opts = OPT_d;
 136
 137        if (opts & OPT_dfis) {
 138                /* Cases when we need full hostname (or its part) */
 139                struct hostent *hp;
 140                char *p;
 141
 142                hp = xgethostbyname(buf);
 143                p = strchrnul(hp->h_name, '.');
 144                if (opts & OPT_f) {
 145                        puts(hp->h_name);
 146                } else if (opts & OPT_s) {
 147                        *p = '\0';
 148                        puts(hp->h_name);
 149                } else if (opts & OPT_d) {
 150                        if (*p)
 151                                puts(p + 1);
 152                } else /*if (opts & OPT_i)*/ {
 153                        if (hp->h_length == sizeof(struct in_addr)) {
 154                                struct in_addr **h_addr_list = (struct in_addr **)hp->h_addr_list;
 155                                while (*h_addr_list) {
 156                                        printf("%s ", inet_ntoa(**h_addr_list));
 157                                        h_addr_list++;
 158                                }
 159                                bb_putchar('\n');
 160                        }
 161                }
 162        } else if (opts & OPT_F) {
 163                /* Set the hostname */
 164                do_sethostname(hostname_str, 1);
 165        } else if (argv[0]) {
 166                /* Set the hostname */
 167                do_sethostname(argv[0], 0);
 168        } else {
 169                /* Just print the current hostname */
 170                puts(buf);
 171        }
 172
 173        if (ENABLE_FEATURE_CLEAN_UP)
 174                free(buf);
 175        return EXIT_SUCCESS;
 176}
 177