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      1 #!/usr/bin/perl
      2 ## -----------------------------------------------------------------------
      3 ##
      4 ##   Copyright 2002-2008 H. Peter Anvin - All Rights Reserved
      5 ##   Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
      6 ##
      7 ##   This program is free software; you can redistribute it and/or modify
      8 ##   it under the terms of the GNU General Public License as published by
      9 ##   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
     10 ##   Boston MA 02111-1307, USA; either version 2 of the License, or
     11 ##   (at your option) any later version; incorporated herein by reference.
     12 ##
     13 ## -----------------------------------------------------------------------
     14 
     15 #
     16 # Creates a blank MS-DOS formatted hard disk image
     17 #
     18 
     19 use bytes;
     20 use integer;
     21 use Fcntl;
     22 use Errno;
     23 use Cwd;
     24 use IO::Handle;			# For flush()
     25 
     26 sub absolute_path($) {
     27     my($f) = @_;
     28     my($c);
     29 
     30     return $f if ( $f =~ /^\// );
     31     $c = cwd();
     32     $c = '' if ( $c eq '/' );
     33     return $c.'/'.$f;
     34 }
     35 
     36 sub is_linux() {
     37     return !!eval '{ '.
     38 	'use POSIX; '.
     39 	'($sysname, $nodename, $release, $version, $machine) = POSIX::uname(); '.
     40 	"return \$sysname eq \'Linux\'; }";
     41 }
     42 
     43 sub get_random() {
     44     # Get a 32-bit random number
     45     my $rfd, $rnd;
     46     my $rid;
     47 
     48     if (open($rfd, "< /dev/urandom\0") && read($rfd, $rnd, 4) == 4) {
     49 	$rid = unpack("V", $rnd);
     50     }
     51 
     52     close($rfd) if (defined($rfd));
     53     return $rid if (defined($rid));
     54 
     55     # This sucks but is better than nothing...
     56     return ($$+time()) & 0xffffffff;
     57 }
     58 
     59 sub get_hex_data() {
     60     my $mbr = '';
     61     my $line, $byte;
     62     while ( $line = <DATA> ) {
     63 	chomp $line;
     64 	last if ($line eq '*');
     65 	foreach $byte ( split(/\s+/, $line) ) {
     66 	    $mbr .= chr(hex($byte));
     67 	}
     68     }
     69     return $mbr;
     70 }
     71 
     72 $is_linux = is_linux();
     73 if ( $is_linux ) {
     74     # IOCTL numbers
     75     $BLKRRPART    = 0x125f;
     76     $BLKGETSIZE   = 0x1260;
     77 }
     78 
     79 %opt = ();
     80 @args = ();
     81 
     82 while (defined($a = shift(@ARGV))) {
     83     if ( $a =~ /^\-/ ) {
     84 	foreach $o ( split(//, substr($a,1)) ) {
     85 	    $opt{$o} = 1;
     86 	    if ($o eq 'i') {
     87 		$id = shift(@ARGV);
     88 	    }
     89 	}
     90     } else {
     91 	push(@args, $a);
     92     }
     93 }
     94 
     95 ($file,$c,$h,$s) = @args;
     96 $c += 0;  $h += 0;  $s += 0;
     97 
     98 $pentry = 1;
     99 $pentry = 2 if ( $opt{'2'} );
    100 $pentry = 3 if ( $opt{'3'} );
    101 $pentry = 4 if ( $opt{'4'} );
    102 
    103 if ( $opt{'z'} ) {
    104     $h = $h || 64;
    105     $s = $s || 32;
    106 }
    107 
    108 if ( $opt{'M'} && $h && $s ) {
    109     # Specify size in megabytes, not in cylinders
    110     $c = ($c*1024*2)/($h*$s);
    111 }
    112 
    113 $is_open = 0;
    114 
    115 if ( $c == 0 && $file ne '' ) {
    116     $len = 0;
    117     if ( sysopen(OUTPUT, $file, O_RDWR, 0666) ) {
    118 	$is_open = 1;
    119 
    120 	if ( (@filestat = stat(OUTPUT)) && S_ISREG($filestat[2]) ) {
    121 	    $len = $filestat[7] >> 9;
    122 	} elsif ( $is_linux && S_ISBLK($filestat[2]) ) {
    123 	    $blksize = pack("L!", 0);
    124 	    if ( ioctl(OUTPUT, $BLKGETSIZE, $blksize) == 0 ) {
    125 		$len = unpack("L!", $blksize); # In 512-byte sectors!
    126 	    }
    127 	}
    128     }
    129 
    130     if ( !$len ) {
    131 	print STDERR "$0: $file: don't know how to determine the size of this device\n";
    132 	exit 1;
    133     }
    134 
    135     $c = $len/($h*$s);
    136 }
    137 
    138 if ( $file eq '' || $c < 1 || $h < 1 || $h > 256 || $s < 1 || $s > 63 ) {
    139     print STDERR "Usage: $0 [-doFMz4][-i id] file c h s (max: 1024 256 63)\n";
    140     print STDERR "    -d    add DOSEMU header\n";
    141     print STDERR "    -o    print filesystem offset to stdout\n";
    142     print STDERR "    -F    format partition as FAT32\n";
    143     print STDERR "    -M    \"c\" argument is megabytes, calculate cylinders\n";
    144     print STDERR "    -z    use zipdisk geometry (h=64 s=32)\n";
    145     print STDERR "    -4    use partition entry 4 (standard for zipdisks)\n";
    146     print STDERR "    -i    specify the MBR ID\n";
    147     print STDERR "    -s    output a sparse file (don't allocate all blocks)\n";
    148     exit 1;
    149 }
    150 
    151 if ($c > 1024) {
    152     print STDERR "Warning: more than 1024 cylinders ($c).\n";
    153     print STDERR "Not all BIOSes will be able to boot this device.\n";
    154     $cc = 1024;
    155 } else {
    156     $cc = $c;
    157 }
    158 
    159 $cylsize = $h*$s*512;
    160 
    161 if ( !$is_open ) {
    162     sysopen(OUTPUT, $file, O_CREAT|O_RDWR|O_TRUNC, 0666)
    163 	or die "$0: Cannot open: $file\n";
    164 }
    165 binmode OUTPUT;
    166 
    167 # Print out DOSEMU header, if requested
    168 if ( $opt{'d'} ) {
    169     $emuhdr = "DOSEMU\0" . pack("VVVV", $h, $s, $c, 128);
    170     $emuhdr .= "\0" x (128 - length($emuhdr));
    171     print OUTPUT $emuhdr;
    172 }
    173 
    174 # Print the MBR and partition table
    175 $mbr = get_hex_data();
    176 if ( length($mbr) > 440 ) {
    177     die "$0: Bad MBR code\n";
    178 }
    179 
    180 $mbr .= "\0" x (440 - length($mbr));
    181 if (defined($id)) {
    182     $id = to_int($id);
    183 } else {
    184     $id = get_random();
    185 }
    186 $mbr .= pack("V", $id);		# Offset 440: MBR ID
    187 $mbr .= "\0\0";			# Offset 446: actual partition table
    188 
    189 print OUTPUT $mbr;
    190 
    191 # Print partition table
    192 $psize = $c*$h*$s-$s;
    193 $bhead   = ($h > 1) ? 1 : 0;
    194 $bsect   = 1;
    195 $bcyl    = ($h > 1) ? 0 : 1;
    196 $ehead   = $h-1;
    197 $esect   = $s + ((($cc-1) & 0x300) >> 2);
    198 $ecyl    = ($cc-1) & 0xff;
    199 if ( $c > 1024 ) {
    200     $fstype = 0x0e;
    201 } elsif ( $psize > 65536 ) {
    202     $fstype = 0x06;
    203 } else {
    204     $fstype = 0x04;
    205 }
    206 for ( $i = 1 ; $i <= 4 ; $i++ ) {
    207     if ( $i == $pentry ) {
    208 	print OUTPUT pack("CCCCCCCCVV", 0x80, $bhead, $bsect, $bcyl, $fstype,
    209 			  $ehead, $esect, $ecyl, $s, $psize);
    210     } else {
    211 	print OUTPUT "\0" x 16;
    212     }
    213 }
    214 print OUTPUT "\x55\xaa";
    215 
    216 # Output blank file
    217 $totalsize = $c*$h*$s;
    218 $tracks    = $c*$h;
    219 
    220 # If -s is given, try to simply use truncate...
    221 unless ($opt{'s'} && truncate(OUTPUT, $totalsize)) {
    222     $track = "\0" x (512*$s);
    223 
    224     # Print fractional track
    225     print OUTPUT "\0" x (512 * ($s-1));
    226 
    227     for ( $i = 1 ; $i < $tracks ; $i++ ) {
    228 	print OUTPUT $track;
    229     }
    230 }
    231 
    232 # Print mtools temp file
    233 $n = 0;
    234 while ( !defined($tmpdir) ) {
    235     $tmpdir = "/tmp/mkdiskimage.$$.".($n++);
    236     if ( !mkdir($tmpdir, 0700) ) {
    237 	die "$0: Failed to make temp directory: $tmpdir\n"
    238 	    if ( $! != EEXIST );
    239 	undef $tmpdir;
    240     }
    241 }
    242 
    243 $cfgfile = $tmpdir.'/mtools.conf';
    244 $imglink = $tmpdir.'/disk.img';
    245 die "$0: Failed to create symlink $imglink\n"
    246     if ( !symlink(absolute_path($file), $imglink) );
    247 
    248 $header_size = ($opt{'d'} ? 128 : 0);
    249 
    250 # Start of filesystem
    251 $offset = $s*512 + $header_size;
    252 
    253 # Start of partition table entry
    254 $pstart = $header_size + 446 + 16*($pentry-1);
    255 
    256 open(MCONFIG, "> ${cfgfile}") or die "$0: Cannot make mtools config\n";
    257 print MCONFIG "drive z:\n";
    258 print MCONFIG "file=\"${imglink}\"\n";
    259 print MCONFIG "cylinders=${c}\n";
    260 print MCONFIG "heads=${h}\n";
    261 print MCONFIG "sectors=${s}\n";
    262 print MCONFIG "offset=${offset}\n";
    263 print MCONFIG "mformat_only\n";
    264 close(MCONFIG);
    265 
    266 # Output the filesystem offset to stdout if appropriate
    267 if ( $opt{'o'} ) {
    268     print $offset, "\n";
    269 }
    270 
    271 $ENV{'MTOOLSRC'} = $cfgfile;
    272 if ( $opt{'F'} ) {
    273     system('mformat', '-F', 'z:');
    274 } else {
    275     system('mformat', 'z:');
    276 }
    277 
    278 # Clean up in /tmp
    279 unlink($cfgfile);
    280 unlink($imglink);
    281 rmdir($tmpdir);
    282 
    283 # MTOOLS doesn't write the bsHiddenSecs field correctly
    284 seek(OUTPUT, $offset + 0x1c, 0);
    285 print OUTPUT pack("V", ($offset-$header_size)>>9);
    286 
    287 # Set the partition type
    288 if ( $opt{'F'} ) {
    289     if ( $c > 1024 ) {
    290 	$fstype = 0x0c;		# FAT32 LBA
    291     } else {
    292 	$fstype = 0x0b;
    293     }
    294 } else {
    295     if ( $c > 1024 ) {
    296 	$fstype = 0x0e;		# FAT16 LBA
    297     } elsif ( $psize > 65536 ) {
    298 	$fstype = 0x06;		# FAT16 > 32MB
    299     } else {
    300 	$fstype = 0x04;		# FAT16 <= 32MB
    301     }
    302     seek(OUTPUT, $offset + 0x36, 0);
    303     read(OUTPUT, $fsname, 8);
    304 
    305     # FAT12: adjust partition type
    306     if ( $fsname eq 'FAT12   ' ) {
    307 	$fstype = 0x01;		# FAT12
    308     }
    309 }
    310 seek(OUTPUT, $pstart+4, 0);
    311 print OUTPUT pack("C", $fstype);
    312 
    313 flush OUTPUT;
    314 
    315 # Just in case this is a block device, try to flush the partition table
    316 if ( $is_linux ) {
    317     ioctl(OUTPUT, $BLKRRPART, 0);
    318 };
    319 
    320 exit 0;
    321 __END__
    322 33 c0 fa 8e d8 8e d0 bc 0 7c 89 e6 6 57 8e c0 fb fc bf 0 6 b9 0 1 f3 a5 ea
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    333 69 70 6c 65 20 61 63 74 69 76 65 20 70 61 72 74 69 74 69 6f 6e 73 2e d a 66
    334 8b 44 8 66 3 46 1c 66 89 44 8 e8 30 ff 72 27 66 81 3e 0 7c 58 46 53 42 75
    335 9 66 83 c0 4 e8 1c ff 72 13 81 3e fe 7d 55 aa f 85 f2 fe bc fa 7b 5a 5f 7
    336 fa ff e4 e8 1e 0 4f 70 65 72 61 74 69 6e 67 20 73 79 73 74 65 6d 20 6c 6f
    337 61 64 20 65 72 72 6f 72 2e d a 5e ac b4 e 8a 3e 62 4 b3 7 cd 10 3c a 75 f1
    338 cd 18 f4 eb fd 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
    339 *
    340