utils/mkdiskimage

   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__
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 338 0 0 0 0 0 0 0 0 0 0 0 0
 339 *