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//config:config HOSTNAME
  13//config:       bool "hostname (5.5 kb)"
  14//config:       default y
  15//config:       help
  16//config:       Show or set the system's host name.
  17//config:
  18//config:config DNSDOMAINNAME
  19//config:       bool "dnsdomainname (3.6 kb)"
  20//config:       default y
  21//config:       help
  22//config:       Alias to "hostname -d".
  23
  24//                        APPLET_NOEXEC:name           main      location    suid_type     help
  25//applet:IF_DNSDOMAINNAME(APPLET_NOEXEC(dnsdomainname, hostname, BB_DIR_BIN, BB_SUID_DROP, dnsdomainname))
  26//applet:IF_HOSTNAME(     APPLET_NOEXEC(hostname,      hostname, BB_DIR_BIN, BB_SUID_DROP, hostname     ))
  27
  28//kbuild: lib-$(CONFIG_HOSTNAME) += hostname.o
  29//kbuild: lib-$(CONFIG_DNSDOMAINNAME) += hostname.o
  30
  31//usage:#define hostname_trivial_usage
  32//usage:       "[OPTIONS] [HOSTNAME | -F FILE]"
  33//usage:#define hostname_full_usage "\n\n"
  34//usage:       "Get or set hostname or DNS domain name\n"
  35//usage:     "\n        -s      Short"
  36//usage:     "\n        -i      Addresses for the hostname"
  37//usage:     "\n        -d      DNS domain name"
  38//usage:     "\n        -f      Fully qualified domain name"
  39//usage:     "\n        -F FILE Use FILE's content as hostname"
  40//usage:
  41//usage:#define hostname_example_usage
  42//usage:       "$ hostname\n"
  43//usage:       "sage\n"
  44//usage:
  45//usage:#define dnsdomainname_trivial_usage NOUSAGE_STR
  46//usage:#define dnsdomainname_full_usage ""
  47
  48#include "libbb.h"
  49
  50static void do_sethostname(char *s, int isfile)
  51{
  52//      if (!s)
  53//              return;
  54        if (isfile) {
  55                parser_t *parser = config_open2(s, xfopen_for_read);
  56                while (config_read(parser, &s, 1, 1, "# \t", PARSE_NORMAL & ~PARSE_GREEDY)) {
  57                        do_sethostname(s, 0);
  58                }
  59                if (ENABLE_FEATURE_CLEAN_UP)
  60                        config_close(parser);
  61        } else if (sethostname(s, strlen(s))) {
  62//              if (errno == EPERM)
  63//                      bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
  64                bb_perror_msg_and_die("sethostname");
  65        }
  66}
  67
  68/* Manpage circa 2009:
  69 *
  70 * hostname [-v] [-a] [--alias] [-d] [--domain] [-f] [--fqdn] [--long]
  71 *      [-i] [--ip-address] [-s] [--short] [-y] [--yp] [--nis]
  72 *
  73 * hostname [-v] [-F filename] [--file filename] / [hostname]
  74 *
  75 * domainname [-v] [-F filename] [--file filename]  / [name]
  76 *  { bbox: not supported }
  77 *
  78 * nodename [-v] [-F filename] [--file filename] / [name]
  79 *  { bbox: not supported }
  80 *
  81 * dnsdomainname [-v]
  82 *  { bbox: supported: Linux kernel build needs this }
  83 * nisdomainname [-v]
  84 *  { bbox: not supported }
  85 * ypdomainname [-v]
  86 *  { bbox: not supported }
  87 *
  88 * -a, --alias
  89 *  Display the alias name of the host (if used).
  90 *  { bbox: not supported }
  91 * -d, --domain
  92 *  Display the name of the DNS domain. Don't use the command
  93 *  domainname to get the DNS domain name because it will show the
  94 *  NIS domain name and not the DNS domain name. Use dnsdomainname
  95 *  instead.
  96 * -f, --fqdn, --long
  97 *  Display the FQDN (Fully Qualified Domain Name). A FQDN consists
  98 *  of a short host name and the DNS domain name. Unless you are
  99 *  using bind or NIS for host lookups you can change the FQDN and
 100 *  the DNS domain name (which is part of the FQDN) in the
 101 *  /etc/hosts file.
 102 * -i, --ip-address
 103 *  Display the IP address(es) of the host.
 104 * -s, --short
 105 *  Display the short host name. This is the host name cut at the
 106 *  first dot.
 107 * -v, --verbose
 108 *  Be verbose and tell what's going on.
 109 *  { bbox: supported but ignored }
 110 * -y, --yp, --nis
 111 *  Display the NIS domain name. If a parameter is given (or --file
 112 *  name ) then root can also set a new NIS domain.
 113 *  { bbox: not supported }
 114 * -F, --file filename
 115 *  Read the host name from the specified file. Comments (lines
 116 *  starting with a '#') are ignored.
 117 */
 118int hostname_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 119int hostname_main(int argc UNUSED_PARAM, char **argv)
 120{
 121        enum {
 122                OPT_d = 0x1,
 123                OPT_f = 0x2,
 124                OPT_i = 0x4,
 125                OPT_s = 0x8,
 126                OPT_F = 0x10,
 127                OPT_dfi = 0x7,
 128        };
 129
 130        unsigned opts;
 131        char *buf;
 132        char *hostname_str;
 133
 134        /* dnsdomainname from net-tools 1.60, hostname 1.100 (2001-04-14),
 135         * supports hostname's options too (not just -v as manpage says) */
 136        opts = getopt32(argv, "dfisF:v", &hostname_str,
 137                "domain\0"     No_argument "d"
 138                "fqdn\0"       No_argument "f"
 139        //Enable if seen in active use in some distro:
 140        //      "long\0"       No_argument "f"
 141        //      "ip-address\0" No_argument "i"
 142        //      "short\0"      No_argument "s"
 143        //      "verbose\0"    No_argument "v"
 144                "file\0"       No_argument "F"
 145        );
 146        argv += optind;
 147        buf = safe_gethostname();
 148        if (ENABLE_DNSDOMAINNAME) {
 149                if (!ENABLE_HOSTNAME || applet_name[0] == 'd') {
 150                        /* dnsdomainname */
 151                        opts = OPT_d;
 152                }
 153        }
 154
 155        if (opts & OPT_dfi) {
 156                /* Cases when we need full hostname (or its part) */
 157                struct hostent *hp;
 158                char *p;
 159
 160                hp = xgethostbyname(buf);
 161                p = strchrnul(hp->h_name, '.');
 162                if (opts & OPT_f) {
 163                        puts(hp->h_name);
 164                } else if (opts & OPT_s) {
 165                        *p = '\0';
 166                        puts(hp->h_name);
 167                } else if (opts & OPT_d) {
 168                        if (*p)
 169                                puts(p + 1);
 170                } else /*if (opts & OPT_i)*/ {
 171                        if (hp->h_length == sizeof(struct in_addr)) {
 172                                struct in_addr **h_addr_list = (struct in_addr **)hp->h_addr_list;
 173                                while (*h_addr_list) {
 174                                        printf(h_addr_list[1] ? "%s " : "%s", inet_ntoa(**h_addr_list));
 175                                        h_addr_list++;
 176                                }
 177                                bb_putchar('\n');
 178                        }
 179                }
 180        } else if (opts & OPT_s) {
 181                strchrnul(buf, '.')[0] = '\0';
 182                puts(buf);
 183        } else if (opts & OPT_F) {
 184                /* Set the hostname */
 185                do_sethostname(hostname_str, 1);
 186        } else if (argv[0]) {
 187                /* Set the hostname */
 188                do_sethostname(argv[0], 0);
 189        } else {
 190                /* Just print the current hostname */
 191                puts(buf);
 192        }
 193
 194        if (ENABLE_FEATURE_CLEAN_UP)
 195                free(buf);
 196        return EXIT_SUCCESS;
 197}
 198