utils/pxelinux-options

   1 #!/usr/bin/perl
   2 #
   3 # Set PXELINUX hard-coded options
   4 #
   5
   6 use Socket;                     # For gethostbyname
   7 use Fcntl;
   8 use bytes;
   9
  10 %option_names = (
  11       6 => 'domain-name-servers',
  12      15 => 'domain-name',
  13      54 => 'next-server',
  14     209 => 'config-file',
  15     210 => 'path-prefix',
  16     211 => 'reboottime'
  17     );
  18
  19 @fmt_oneip   = ("ip-address", \&parse_oneip, \&show_ip);
  20 @fmt_multiip = ("ip-address-list", \&parse_multiip, \&show_ip);
  21 @fmt_string  = ("string", \&parse_string, \&show_string);
  22 @fmt_uint32  = ("uint32", \&parse_uint32, \&show_uint32);
  23
  24 %option_format = (
  25       6 => \@fmt_multiip,
  26      15 => \@fmt_string,
  27      54 => \@fmt_oneip,
  28      67 => \@fmt_string,
  29     209 => \@fmt_string,
  30     210 => \@fmt_string,
  31     211 => \@fmt_uint32
  32     );
  33
  34 sub parse_oneip($)
  35 {
  36     my($s) = @_;
  37     my($name,$aliases,$addrtype,$length,@addrs) = gethostbyname($s);
  38
  39     return ($addrtype == AF_INET) ? $addrs[0] : undef;
  40 }
  41
  42 sub parse_multiip($)
  43 {
  44     my($l) = @_;
  45     my $s;
  46     my @a = ();
  47     my $addr;
  48     my $d = '';
  49
  50     foreach $s (split(/,/, $l)) {
  51         my($name,$aliases,$addrtype,$length,@addrs)
  52             = gethostbyname($s);
  53         if ($addrtype == AF_INET) {
  54             foreach $addr (@addrs) {
  55                 $d .= $addr;
  56             }
  57         }
  58     }
  59
  60     return $d ne '' ? $d : undef;
  61 }
  62
  63 sub show_ip($)
  64 {
  65     my($l) = @_;
  66
  67     if (length($l) & 3) {
  68         return undef;
  69     } else {
  70         my @h = ();
  71         my $i;
  72
  73         for ($i = 0; $i < length($l); $i += 4) {
  74             push(@h, inet_ntoa(substr($l, $i, 4)));
  75         }
  76
  77         return join(',', @h);
  78     }
  79 }
  80
  81 sub parse_string($)
  82 {
  83     return $_[0];
  84 }
  85
  86 sub show_string($)
  87 {
  88     my($s) = @_;
  89     my $o, $i, $c;
  90
  91     $o = "\'";
  92     for ($i = 0; $i < length($s); $i++) {
  93         $c = substr($s, $i, 1);
  94         if ($c eq "\'" || $c eq '!') {
  95             $o .= "\'\\$c\'";
  96         } else {
  97             $o .= $c;
  98         }
  99     }
 100     $o .= "\'";
 101
 102     return $o;
 103 }
 104
 105 sub parse_uint32($)
 106 {
 107     my($s) = @_;
 108
 109     if ($s =~ /^[0-9]+$/) {
 110         return pack("N", $s);
 111     } else {
 112         return undef;
 113     }
 114 }
 115
 116 sub show_uint32($)
 117 {
 118     my($l) = @_;
 119
 120     if (length($l) == 4) {
 121         return unpack("N", $l);
 122     } else {
 123         return undef;
 124     }
 125 }
 126
 127 sub parse_generic($)
 128 {
 129     my($s) = @_;
 130
 131     if ($s =~ /^[0-9a-f]{1,2}(:[0-9a-f]{1,2})*$/) {
 132         my $h;
 133         my @b = ();
 134
 135         foreach $h (split(/\:/, $s)) {
 136             push(@b, hex $h);
 137         }
 138
 139         return pack("C", @b);
 140     } else {
 141         return undef;
 142     }
 143 }
 144
 145 sub show_generic($)
 146 {
 147     my($l) = @_;
 148     my $i;
 149     my @h;
 150
 151     for ($i = 0; $i < length($l); $i++) {
 152         push(@h, sprintf("%02x", unpack("C", substr($l, $i, $1))));
 153     }
 154
 155     return join(':', @h);
 156 }
 157
 158 sub parse_option($$)
 159 {
 160     my($opt, $arg) = @_;
 161     my $v;
 162
 163     if (defined($option_format{$opt})) {
 164         $v = $option_format{$opt}[1]($arg);
 165         return $v if (defined($v));
 166     }
 167
 168     return parse_generic($arg);
 169 }
 170
 171 sub show_option($$)
 172 {
 173     my($opt, $arg) = @_;
 174     my $v;
 175
 176     if (defined($option_format{$opt})) {
 177         $v = $option_format{$opt}[2]($arg);
 178         return $v if (defined($v));
 179     }
 180
 181     return show_generic($arg);
 182 }
 183
 184 sub option_number($)
 185 {
 186     my($n) = @_;
 187
 188     if (defined($option_rnames{$n})) {
 189         return $option_rnames{$n};
 190     } elsif ($n =~ /^[0-9]+$/ && $n >= 1 && $n <= 254) {
 191         return $n+0;
 192     } else {
 193         return undef;
 194     }
 195 }
 196
 197 sub read_optsets($)
 198 {
 199     my($file) = @_;
 200     my $data, $bdata, $adata;
 201     my $patch_start = (stat($file))[7];
 202
 203     return undef unless (seek($file, 8, SEEK_SET));
 204     return undef unless (read($file, $data, 7*4) == 7*4);
 205
 206     my($magic, $len, $flags, $boff, $blen, $aoff, $alen)
 207         = unpack("VVVVVVV", $data);
 208     return undef if ($magic != 0x2983c8ac);
 209     return undef if ($len < 7*4);
 210
 211     if ($blen == 0) {
 212         $bdata = '';
 213     } else {
 214         return undef unless (seek($file, $boff, SEEK_SET));
 215         return undef unless (read($file, $bdata, $blen) == $blen);
 216         $patch_start = $boff if ($boff < $patch_start);
 217     }
 218
 219     if ($alen == 0) {
 220         $adata = '';
 221     } else {
 222         return undef unless (seek($file, $aoff, SEEK_SET));
 223         return undef unless (read($file, $adata, $alen) == $alen);
 224         $patch_start = $aoff if ($aoff < $patch_start);
 225     }
 226
 227     return ($patch_start, $bdata, $adata);
 228 }
 229
 230 sub write_optsets($$@)
 231 {
 232     my($file, $patch_start, $bdata, $adata) = @_;
 233     my $boff = 0;
 234     my $aoff = 0;
 235
 236     if (length($bdata) > 0) {
 237         $bdata .= "\xff";
 238         $boff = $patch_start;
 239         return undef unless (seek($file, $boff, SEEK_SET));
 240         return undef unless (print $file $bdata);
 241         $patch_start += length($bdata);
 242     }
 243
 244     if (length($adata) > 0) {
 245         $adata .= "\xff";
 246         $aoff = $patch_start;
 247         return undef unless (seek($file, $aoff, SEEK_SET));
 248         return undef unless (print $file $adata);
 249         $patch_start += length($adata);
 250     }
 251
 252     my $hdr = pack("VVVV", $boff, length($bdata), $aoff, length($adata));
 253
 254     return undef unless (seek($file, 8+3*4, SEEK_SET));
 255     return undef unless (print $file $hdr);
 256
 257     truncate($file, $patch_start);
 258     return 1;
 259 }
 260
 261 sub delete_option($$)
 262 {
 263     my ($num, $block) = @_;
 264     my $o, $l, $c, $x;
 265
 266     $x = 0;
 267     while ($x < length($block)) {
 268         ($o, $l) = unpack("CC", substr($block, $x, 2));
 269         if ($o == $num) {
 270             # Delete this option
 271             substr($block, $x, $l+2) = '';
 272         } elsif ($o == 0) {
 273             # Delete a null option
 274             substr($block, $x, 1) = '';
 275         } elsif ($o == 255) {
 276             # End marker - truncate block
 277             $block = substr($block, 0, $x);
 278             last;
 279         } else {
 280             # Skip to the next option
 281             $x += $l+2;
 282         }
 283     }
 284
 285     return $block;
 286 }
 287
 288 sub add_option($$$)
 289 {
 290     my ($num, $data, $block) = @_;
 291
 292     $block = delete_option($num, $block);
 293
 294     if (length($data) == 0) {
 295         return $block;
 296     } elsif (length($data) > 255) {
 297         die "$0: option $num has too much data (max 255 bytes)\n";
 298     } else {
 299         return $block . pack("CC", $num, length($data)) . $data;
 300     }
 301 }
 302
 303 sub list_options($$)
 304 {
 305     my($pfx, $data) = @_;
 306     my $x, $o, $l;
 307
 308     while ($x < length($data)) {
 309         ($o, $l) = unpack("CC", substr($data, $x, 2));
 310
 311         if ($o == 0) {
 312             $x++;
 313         } elsif ($o == 255) {
 314             last;
 315         } else {
 316             my $odata = substr($data, $x+2, $l);
 317             last if (length($odata) != $l); # Incomplete option
 318
 319             printf "%s%-20s %s\n", $pfx,
 320                 $option_names{$o} || sprintf("%d", $o),
 321                 show_option($o, $odata);
 322
 323             $x += $l+2;
 324         }
 325     }
 326 }
 327
 328 sub usage()
 329 {
 330     my $i;
 331
 332     print STDERR "Usage: $0 options pxelinux.0\n";
 333     print STDERR "Options:\n";
 334     print STDERR "--before option value   -b   Add an option before DHCP data\n";
 335     print STDERR "--after  option value   -a   Add an option after DHCP data\n";
 336     print STDERR "--delete option         -d   Delete an option\n";
 337     print STDERR "--list                  -l   List set options\n";
 338     print STDERR "--dry-run               -n   Don't modify the target file\n";
 339     print STDERR "--help                  -h   Display this help text\n";
 340     print STDERR "\n";
 341     print STDERR "The following DHCP options are currently recognized:\n";
 342     printf STDERR "%-23s %-3s  %s\n", 'Name', 'Num', 'Value Format';
 343
 344     foreach $i (sort { $a <=> $b } keys(%option_names)) {
 345         printf STDERR "%-23s %3d  %s\n",
 346                 $option_names{$i}, $i, $option_format{$i}[0];
 347     }
 348 }
 349
 350 %option_rnames = ();
 351 foreach $opt (keys(%option_names)) {
 352     $option_rnames{$option_names{$opt}} = $opt;
 353 }
 354
 355 %before   = ();
 356 %after    = ();
 357 @clear    = ();
 358 $usage    = 0;
 359 $err      = 0;
 360 $list     = 0;
 361 $no_write = 0;
 362 undef $file;
 363
 364 while (defined($opt = shift(@ARGV))) {
 365     if ($opt !~ /^-/) {
 366         if (defined($file)) {
 367             $err = $usage = 1;
 368             last;
 369         }
 370         $file = $opt;
 371     } elsif ($opt eq '-b' || $opt eq '--before') {
 372         $oname = shift(@ARGV);
 373         $odata = shift(@ARGV);
 374
 375         if (!defined($odata)) {
 376             $err = $usage = 1;
 377             last;
 378         }
 379
 380         $onum = option_number($oname);
 381         if (!defined($onum)) {
 382             print STDERR "$0: unknown option name: $oname\n";
 383             $err = 1;
 384             next;
 385         }
 386
 387         $odata = parse_option($onum, $odata);
 388         if (!defined($odata)) {
 389             print STDERR "$0: unable to parse data for option $oname\n";
 390             $err = 1;
 391             next;
 392         }
 393
 394         delete $after{$onum};
 395         $before{$onum} = $odata;
 396         push(@clear, $onum);
 397     } elsif ($opt eq '-a' || $opt eq '--after') {
 398         $oname = shift(@ARGV);
 399         $odata = shift(@ARGV);
 400
 401         if (!defined($odata)) {
 402             $err = $usage = 1;
 403             last;
 404         }
 405
 406         $onum = option_number($oname);
 407         if (!defined($onum)) {
 408             print STDERR "$0: unknown option name: $oname\n";
 409             $err = 1;
 410             next;
 411         }
 412
 413         $odata = parse_option($onum, $odata);
 414         if (!defined($odata)) {
 415             print STDERR "$0: unable to parse data for option $oname\n";
 416             $err = 1;
 417             next;
 418         }
 419
 420         delete $before{$onum};
 421         $after{$onum} = $odata;
 422         push(@clear, $onum);
 423     } elsif ($opt eq '-d' || $opt eq '--delete') {
 424         $oname = shift(@ARGV);
 425
 426         if (!defined($oname)) {
 427             $err = $usage = 1;
 428             last;
 429         }
 430
 431         $onum = option_number($oname);
 432         if (!defined($onum)) {
 433             print STDERR "$0: unknown option name: $oname\n";
 434             $err = 1;
 435             next;
 436         }
 437
 438         push(@clear, $onum);
 439         delete $before{$onum};
 440         delete $after{$onum};
 441     } elsif ($opt eq '-n' || $opt eq '--no-write' || $opt eq '--dry-run') {
 442         $no_write = 1;
 443     } elsif ($opt eq '-l' || $opt eq '--list') {
 444         $list = 1;
 445     } elsif ($opt eq '-h' || $opt eq '--help') {
 446         $usage = 1;
 447     } else {
 448         print STDERR "Invalid option: $opt\n";
 449         $err = $usage = 1;
 450     }
 451 }
 452
 453 if (!defined($file) && !$usage) {
 454     $err = $usage = 1;
 455 }
 456 if ($usage) {
 457     usage();
 458 }
 459 if ($err || $usage) {
 460     exit($err);
 461 }
 462
 463 if (!scalar(@clear)) {
 464     $no_write = 1;              # No modifications requested
 465 }
 466
 467 $mode = $no_write ? '<' : '+<';
 468
 469 open(FILE, $mode, $file)
 470     or die "$0: cannot open: $file: $!\n";
 471 ($patch_start, @data) = read_optsets(\*FILE);
 472 if (!defined($patch_start)) {
 473     die "$0: $file: patch block not found or file corrupt\n";
 474 }
 475
 476 foreach $o (@clear) {
 477     $data[0] = delete_option($o, $data[0]);
 478     $data[1] = delete_option($o, $data[1]);
 479 }
 480 foreach $o (keys(%before)) {
 481     $data[0] = add_option($o, $before{$o}, $data[0]);
 482 }
 483 foreach $o (keys(%after)) {
 484     $data[1] = add_option($o, $after{$o}, $data[1]);
 485 }
 486
 487 if ($list) {
 488     list_options('-b ', $data[0]);
 489     list_options('-a ', $data[1]);
 490 }
 491
 492 if (!$no_write) {
 493     if (!write_optsets(\*FILE, $patch_start, @data)) {
 494         die "$0: $file: failed to write options: $!\n";
 495     }
 496 }
 497
 498 close(FILE);
 499 exit 0;