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     my $hdroffset = 0;          # 0 means non-deep-embedded
 203     my $bufsize = 0;
 204     my $junk;
 205     my %hdr;
 206
 207     return undef unless (seek($file, 0, SEEK_SET));
 208     return undef unless (read($file, $data, 48) == 48);
 209
 210     my($mzmagic, $junk, $magic, $len, $flags, $boff, $blen, $aoff, $alen)
 211         = unpack("va[6]VVVVVVV", $data);
 212
 213     if ($mzmagic == 0x5a4d) {
 214         # It is an EFI file... search for the magic number
 215         $hdroffset = 48;
 216         my $magic = pack("VVVV", 0x2a171ead, 0x0600e65e,
 217                          0x4025a4e4, 0x42388fc8);
 218
 219         while (1) {
 220             return undef unless (read($file, $data, 16) == 16);
 221             last if ($data eq $magic);
 222
 223             $hdroffset += 16;
 224         }
 225
 226         return undef unless (read($file, $data, 16) == 16);
 227         ($blen, $alen, $bufsize, $junk) = unpack("VVVV", $data);
 228
 229         $patch_start = $boff = $hdroffset + 32;
 230         $aoff = $boff + $blen;
 231
 232         $hdr{'deep'} = 1;
 233         $hdr{'bufsize'} = $bufsize;
 234         $hdr{'hdroffset'} = $hdroffset;
 235     } else {
 236         # It is a BIOS PXE file
 237
 238         return undef if ($magic != 0x2983c8ac);
 239         return undef if ($len < 7*4);
 240
 241         $hdr{'deep'} = 0;
 242     }
 243
 244     if ($blen == 0) {
 245         $bdata = '';
 246     } else {
 247         return undef unless (seek($file, $boff, SEEK_SET));
 248         return undef unless (read($file, $bdata, $blen) == $blen);
 249         $patch_start = $boff if ($boff < patch_start);
 250     }
 251
 252     if ($alen == 0) {
 253         $adata = '';
 254     } else {
 255         return undef unless (seek($file, $aoff, SEEK_SET));
 256         return undef unless (read($file, $adata, $alen) == $alen);
 257         $patch_start = $aoff if ($aoff < $patch_start);
 258     }
 259
 260     $hdr{'patch_start'} = $patch_start;
 261
 262     return (\%hdr, $bdata, $adata);
 263 }
 264
 265 sub write_optsets($$@)
 266 {
 267     my($file, $hdr, $bdata, $adata) = @_;
 268     my $boff = 0;
 269     my $aoff = 0;
 270     my $bufsize = 0;
 271     my $patch_start = $hdr->{'patch_start'};
 272     my $len;
 273
 274     $bdata .= "\xff" unless ($bdata eq '');
 275     $adata .= "\xff" unless ($adata eq '');
 276
 277     $len = length($bdata) + length($adata);
 278
 279     if (defined($hdr->{'bufsize'})) {
 280         return undef unless ($len <= $hdr->{'bufsize'});
 281     }
 282
 283     return undef unless (seek($file, $patch_start, SEEK_SET));
 284
 285     if (length($bdata)) {
 286         $boff = $patch_start;
 287         return undef unless (print $file $bdata);
 288         $patch_start += length($bdata);
 289     }
 290
 291     if (length($adata)) {
 292         $aoff = $patch_start;
 293         return undef unless (print $file $adata);
 294         $patch_start += length($adata);
 295     }
 296
 297     if ($hdr->{'deep'}) {
 298         return undef unless (print $file "\0" x ($hdr->{'bufsize'} - $len));
 299         return undef unless (seek($file, $hdr->{'hdroffset'} + 16, SEEK_SET));
 300         my $hdr = pack("VV", length($bdata), length($adata));
 301         return undef unless (print $file $hdr);
 302     } else {
 303         my $hdr = pack("VVVV", $boff, length($bdata), $aoff, length($adata));
 304
 305         return undef unless (seek($file, 8+3*4, SEEK_SET));
 306         return undef unless (print $file $hdr);
 307
 308         truncate($file, $patch_start);
 309     }
 310
 311     return 1;
 312 }
 313
 314 sub delete_option($$)
 315 {
 316     my ($num, $block) = @_;
 317     my $o, $l, $c, $x;
 318
 319     $x = 0;
 320     while ($x < length($block)) {
 321         ($o, $l) = unpack("CC", substr($block, $x, 2));
 322         if ($o == $num) {
 323             # Delete this option
 324             substr($block, $x, $l+2) = '';
 325         } elsif ($o == 0) {
 326             # Delete a null option
 327             substr($block, $x, 1) = '';
 328         } elsif ($o == 255) {
 329             # End marker - truncate block
 330             $block = substr($block, 0, $x);
 331             last;
 332         } else {
 333             # Skip to the next option
 334             $x += $l+2;
 335         }
 336     }
 337
 338     return $block;
 339 }
 340
 341 sub add_option($$$)
 342 {
 343     my ($num, $data, $block) = @_;
 344
 345     $block = delete_option($num, $block);
 346
 347     if (length($data) == 0) {
 348         return $block;
 349     } elsif (length($data) > 255) {
 350         die "$0: option $num has too much data (max 255 bytes)\n";
 351     } else {
 352         return $block . pack("CC", $num, length($data)) . $data;
 353     }
 354 }
 355
 356 sub list_options($$)
 357 {
 358     my($pfx, $data) = @_;
 359     my $x, $o, $l;
 360
 361     while ($x < length($data)) {
 362         ($o, $l) = unpack("CC", substr($data, $x, 2));
 363
 364         if ($o == 0) {
 365             $x++;
 366         } elsif ($o == 255) {
 367             last;
 368         } else {
 369             my $odata = substr($data, $x+2, $l);
 370             last if (length($odata) != $l); # Incomplete option
 371
 372             printf "%s%-20s %s\n", $pfx,
 373                 $option_names{$o} || sprintf("%d", $o),
 374                 show_option($o, $odata);
 375
 376             $x += $l+2;
 377         }
 378     }
 379 }
 380
 381 sub usage()
 382 {
 383     my $i;
 384
 385     print STDERR "Usage: $0 options pxelinux.0\n";
 386     print STDERR "Options:\n";
 387     print STDERR "--before option value   -b   Add an option before DHCP data\n";
 388     print STDERR "--after  option value   -a   Add an option after DHCP data\n";
 389     print STDERR "--delete option         -d   Delete an option\n";
 390     print STDERR "--list                  -l   List set options\n";
 391     print STDERR "--dry-run               -n   Don't modify the target file\n";
 392     print STDERR "--help                  -h   Display this help text\n";
 393     print STDERR "\n";
 394     print STDERR "The following DHCP options are currently recognized:\n";
 395     printf STDERR "%-23s %-3s  %s\n", 'Name', 'Num', 'Value Format';
 396
 397     foreach $i (sort { $a <=> $b } keys(%option_names)) {
 398         printf STDERR "%-23s %3d  %s\n",
 399                 $option_names{$i}, $i, $option_format{$i}[0];
 400     }
 401 }
 402
 403 %option_rnames = ();
 404 foreach $opt (keys(%option_names)) {
 405     $option_rnames{$option_names{$opt}} = $opt;
 406 }
 407
 408 %before   = ();
 409 %after    = ();
 410 @clear    = ();
 411 $usage    = 0;
 412 $err      = 0;
 413 $list     = 0;
 414 $no_write = 0;
 415 undef $file;
 416
 417 while (defined($opt = shift(@ARGV))) {
 418     if ($opt !~ /^-/) {
 419         if (defined($file)) {
 420             $err = $usage = 1;
 421             last;
 422         }
 423         $file = $opt;
 424     } elsif ($opt eq '-b' || $opt eq '--before') {
 425         $oname = shift(@ARGV);
 426         $odata = shift(@ARGV);
 427
 428         if (!defined($odata)) {
 429             $err = $usage = 1;
 430             last;
 431         }
 432
 433         $onum = option_number($oname);
 434         if (!defined($onum)) {
 435             print STDERR "$0: unknown option name: $oname\n";
 436             $err = 1;
 437             next;
 438         }
 439
 440         $odata = parse_option($onum, $odata);
 441         if (!defined($odata)) {
 442             print STDERR "$0: unable to parse data for option $oname\n";
 443             $err = 1;
 444             next;
 445         }
 446
 447         delete $after{$onum};
 448         $before{$onum} = $odata;
 449         push(@clear, $onum);
 450     } elsif ($opt eq '-a' || $opt eq '--after') {
 451         $oname = shift(@ARGV);
 452         $odata = shift(@ARGV);
 453
 454         if (!defined($odata)) {
 455             $err = $usage = 1;
 456             last;
 457         }
 458
 459         $onum = option_number($oname);
 460         if (!defined($onum)) {
 461             print STDERR "$0: unknown option name: $oname\n";
 462             $err = 1;
 463             next;
 464         }
 465
 466         $odata = parse_option($onum, $odata);
 467         if (!defined($odata)) {
 468             print STDERR "$0: unable to parse data for option $oname\n";
 469             $err = 1;
 470             next;
 471         }
 472
 473         delete $before{$onum};
 474         $after{$onum} = $odata;
 475         push(@clear, $onum);
 476     } elsif ($opt eq '-d' || $opt eq '--delete') {
 477         $oname = shift(@ARGV);
 478
 479         if (!defined($oname)) {
 480             $err = $usage = 1;
 481             last;
 482         }
 483
 484         $onum = option_number($oname);
 485         if (!defined($onum)) {
 486             print STDERR "$0: unknown option name: $oname\n";
 487             $err = 1;
 488             next;
 489         }
 490
 491         push(@clear, $onum);
 492         delete $before{$onum};
 493         delete $after{$onum};
 494     } elsif ($opt eq '-n' || $opt eq '--no-write' || $opt eq '--dry-run') {
 495         $no_write = 1;
 496     } elsif ($opt eq '-l' || $opt eq '--list') {
 497         $list = 1;
 498     } elsif ($opt eq '-h' || $opt eq '--help') {
 499         $usage = 1;
 500     } else {
 501         print STDERR "Invalid option: $opt\n";
 502         $err = $usage = 1;
 503     }
 504 }
 505
 506 if (!defined($file) && !$usage) {
 507     $err = $usage = 1;
 508 }
 509 if ($usage) {
 510     usage();
 511 }
 512 if ($err || $usage) {
 513     exit($err);
 514 }
 515
 516 if (!scalar(@clear)) {
 517     $no_write = 1;              # No modifications requested
 518 }
 519
 520 $mode = $no_write ? '<' : '+<';
 521
 522 open(FILE, $mode, $file)
 523     or die "$0: cannot open: $file: $!\n";
 524 ($hdrinfo, @data) = read_optsets(\*FILE);
 525 if (!defined($hdrinfo)) {
 526     die "$0: $file: patch block not found or file corrupt\n";
 527 }
 528
 529 foreach $o (@clear) {
 530     $data[0] = delete_option($o, $data[0]);
 531     $data[1] = delete_option($o, $data[1]);
 532 }
 533 foreach $o (keys(%before)) {
 534     $data[0] = add_option($o, $before{$o}, $data[0]);
 535 }
 536 foreach $o (keys(%after)) {
 537     $data[1] = add_option($o, $after{$o}, $data[1]);
 538 }
 539
 540 if ($list) {
 541     list_options('-b ', $data[0]);
 542     list_options('-a ', $data[1]);
 543 }
 544
 545 if (!$no_write) {
 546     if (!write_optsets(\*FILE, $hdrinfo, @data)) {
 547         die "$0: $file: failed to write options: $!\n";
 548     }
 549 }
 550
 551 close(FILE);
 552 exit 0;