LXR toybox/toys/lsb/hostname.c

   1/* hostname.c - Get/Set the hostname
   2 *
   3 * Copyright 2012 Andre Renaud <andre@bluewatersys.com>
   4 *
   5 * http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/hostname.html
   6
   7USE_HOSTNAME(NEWTOY(hostname, ">1bdsfF:[!bdsf]", TOYFLAG_BIN))
   8
   9config HOSTNAME
  10  bool "hostname"
  11  default y
  12  help
  13    usage: hostname [-bdsf] [-F FILENAME] [newname]
  14
  15    Get/set the current hostname.
  16
  17    -b  Set hostname to 'localhost' if otherwise unset
  18    -d  Show DNS domain name (no host)
  19    -f  Show fully-qualified name (host+domain, FQDN)
  20    -F  Set hostname to contents of FILENAME
  21    -s  Show short host name (no domain)
  22*/
  23
  24#define FOR_hostname
  25#include "toys.h"
  26
  27GLOBALS(
  28  char *F;
  29)
  30
  31void hostname_main(void)
  32{
  33  char *hostname = *toys.optargs, *dot;
  34  struct hostent *h;
  35
  36  if (TT.F && (hostname = xreadfile(TT.F, 0, 0))) {
  37    if (!*chomp(hostname)) {
  38      if (CFG_TOYBOX_FREE) free(hostname);
  39      if (!FLAG(b)) error_exit("empty '%s'", TT.F);
  40      hostname = 0;
  41    }
  42  }
  43
  44  // Implement -b.
  45  if (!hostname && FLAG(b))
  46    if (gethostname(toybuf, sizeof(toybuf)-1) || !*toybuf)
  47      hostname = "localhost";
  48
  49  // Setting?
  50  if (hostname) {
  51    if (sethostname(hostname, strlen(hostname)))
  52      perror_exit("set '%s'", hostname);
  53    return;
  54  }
  55
  56  // Get the hostname.
  57  if (gethostname(toybuf, sizeof(toybuf)-1)) perror_exit("gethostname");
  58  // We only do the DNS lookup for -d and -f.
  59  if (FLAG(d) || FLAG(f)) {
  60    if (!(h = gethostbyname(toybuf))) perror_exit("gethostbyname");
  61    snprintf(toybuf, sizeof(toybuf), "%s", h->h_name);
  62  }
  63  dot = strchr(toybuf, '.');
  64  if (FLAG(s) && dot) *dot = '\0';
  65  xputs(FLAG(d) ? dot+1 : toybuf);
  66}
  67