text: /* 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;
  }
  