/* vi: set sw=4 ts=4: */
/*
 * Mini hostname implementation for busybox
 *
 * Copyright (C) 1999 by Randolph Chung <tausq@debian.org>
 *
 * Adjusted by Erik Andersen <andersen@codepoet.org> to remove
 * use of long options and GNU getopt.  Improved the usage info.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
#include "libbb.h"

static void do_sethostname(char *s, int isfile)
{
//      if (!s)
//              return;
        if (isfile) {
                parser_t *parser = config_open2(s, xfopen_for_read);
                while (config_read(parser, &s, 1, 1, "# \t", PARSE_NORMAL & ~PARSE_GREEDY)) {
                        do_sethostname(s, 0);
                }
                if (ENABLE_FEATURE_CLEAN_UP)
                        config_close(parser);
        } else if (sethostname(s, strlen(s))) {
//              if (errno == EPERM)
//                      bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
                bb_perror_msg_and_die("sethostname");
        }
}

/* Manpage circa 2009:
 *
 * hostname [-v] [-a] [--alias] [-d] [--domain] [-f] [--fqdn] [--long]
 *      [-i] [--ip-address] [-s] [--short] [-y] [--yp] [--nis]
 *
 * hostname [-v] [-F filename] [--file filename] / [hostname]
 *
 * domainname [-v] [-F filename] [--file filename]  / [name]
 *  { bbox: not supported }
 *
 * nodename [-v] [-F filename] [--file filename] / [name]
 *  { bbox: not supported }
 *
 * dnsdomainname [-v]
 *  { bbox: supported: Linux kernel build needs this }
 * nisdomainname [-v]
 *  { bbox: not supported }
 * ypdomainname [-v]
 *  { bbox: not supported }
 *
 * -a, --alias
 *  Display the alias name of the host (if used).
 *  { bbox: not supported }
 * -d, --domain
 *  Display the name of the DNS domain. Don't use the command
 *  domainname to get the DNS domain name because it will show the
 *  NIS domain name and not the DNS domain name. Use dnsdomainname
 *  instead.
 * -f, --fqdn, --long
 *  Display the FQDN (Fully Qualified Domain Name). A FQDN consists
 *  of a short host name and the DNS domain name. Unless you are
 *  using bind or NIS for host lookups you can change the FQDN and
 *  the DNS domain name (which is part of the FQDN) in the
 *  /etc/hosts file.
 * -i, --ip-address
 *  Display the IP address(es) of the host.
 * -s, --short
 *  Display the short host name. This is the host name cut at the
 *  first dot.
 * -v, --verbose
 *  Be verbose and tell what's going on.
 *  { bbox: supported but ignored }
 * -y, --yp, --nis
 *  Display the NIS domain name. If a parameter is given (or --file
 *  name ) then root can also set a new NIS domain.
 *  { bbox: not supported }
 * -F, --file filename
 *  Read the host name from the specified file. Comments (lines
 *  starting with a `#') are ignored.
 */
int hostname_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int hostname_main(int argc UNUSED_PARAM, char **argv)
{
        enum {
                OPT_d = 0x1,
                OPT_f = 0x2,
                OPT_i = 0x4,
                OPT_s = 0x8,
                OPT_F = 0x10,
                OPT_dfis = 0xf,
        };

        unsigned opts;
        char *buf;
        char *hostname_str;

#if ENABLE_LONG_OPTS
        applet_long_options =
                "domain\0"     No_argument "d"
                "fqdn\0"       No_argument "f"
        //Enable if seen in active use in some distro:
        //      "long\0"       No_argument "f"
        //      "ip-address\0" No_argument "i"
        //      "short\0"      No_argument "s"
        //      "verbose\0"    No_argument "v"
                "file\0"       No_argument "F"
                ;

#endif
        /* dnsdomainname from net-tools 1.60, hostname 1.100 (2001-04-14),
         * supports hostname's options too (not just -v as manpage says) */
        opts = getopt32(argv, "dfisF:v", &hostname_str);
        argv += optind;
        buf = safe_gethostname();
        if (applet_name[0] == 'd') /* dnsdomainname? */
                opts = OPT_d;

        if (opts & OPT_dfis) {
                /* Cases when we need full hostname (or its part) */
                struct hostent *hp;
                char *p;

                hp = xgethostbyname(buf);
                p = strchrnul(hp->h_name, '.');
                if (opts & OPT_f) {
                        puts(hp->h_name);
                } else if (opts & OPT_s) {
                        *p = '\0';
                        puts(hp->h_name);
                } else if (opts & OPT_d) {
                        if (*p)
                                puts(p + 1);
                } else /*if (opts & OPT_i)*/ {
                        if (hp->h_length == sizeof(struct in_addr)) {
                                struct in_addr **h_addr_list = (struct in_addr **)hp->h_addr_list;
                                while (*h_addr_list) {
                                        printf("%s ", inet_ntoa(**h_addr_list));
                                        h_addr_list++;
                                }
                                bb_putchar('\n');
                        }
                }
        } else if (opts & OPT_F) {
                /* Set the hostname */
                do_sethostname(hostname_str, 1);
        } else if (argv[0]) {
                /* Set the hostname */
                do_sethostname(argv[0], 0);
        } else {
                /* Just print the current hostname */
                puts(buf);
        }

        if (ENABLE_FEATURE_CLEAN_UP)
                free(buf);
        return EXIT_SUCCESS;
}