mkdiskimage.in

   1 #!/usr/bin/perl
   2 ## -----------------------------------------------------------------------
   3 ##
   4 ##   Copyright 2002-2007 H. Peter Anvin - All Rights Reserved
   5 ##
   6 ##   This program is free software; you can redistribute it and/or modify
   7 ##   it under the terms of the GNU General Public License as published by
   8 ##   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
   9 ##   Boston MA 02111-1307, USA; either version 2 of the License, or
  10 ##   (at your option) any later version; incorporated herein by reference.
  11 ##
  12 ## -----------------------------------------------------------------------
  13
  14 #
  15 # Creates a blank MS-DOS formatted hard disk image
  16 #
  17
  18 use bytes;
  19 use integer;
  20 use Fcntl;
  21 use Errno;
  22 use Cwd;
  23 use IO::Handle;                 # For flush()
  24
  25 sub absolute_path($) {
  26     my($f) = @_;
  27     my($c);
  28
  29     return $f if ( $f =~ /^\// );
  30     $c = cwd();
  31     $c = '' if ( $c eq '/' );
  32     return $c.'/'.$f;
  33 }
  34
  35 sub is_linux() {
  36     return !!eval '{ '.
  37         'use POSIX; '.
  38         '($sysname, $nodename, $release, $version, $machine) = POSIX::uname(); '.
  39         "return \$sysname eq \'Linux\'; }";
  40 }
  41
  42
  43 $is_linux = is_linux();
  44 if ( $is_linux ) {
  45     # IOCTL numbers
  46     $BLKRRPART    = 0x125f;
  47     $BLKGETSIZE   = 0x1260;
  48 }
  49
  50 %opt = ();
  51 @args = ();
  52
  53 for $a ( @ARGV ) {
  54     if ( $a =~ /^\-/ ) {
  55         foreach $o ( split(//, substr($a,1)) ) {
  56             $opt{$o} = 1;
  57         }
  58     } else {
  59         push(@args, $a);
  60     }
  61 }
  62
  63 ($file,$c,$h,$s) = @args;
  64 $c += 0;  $h += 0;  $s += 0;
  65
  66 $pentry = 1;
  67 $pentry = 2 if ( $opt{'2'} );
  68 $pentry = 3 if ( $opt{'3'} );
  69 $pentry = 4 if ( $opt{'4'} );
  70
  71 if ( $opt{'z'} ) {
  72     $h = $h || 64;
  73     $s = $s || 32;
  74 }
  75
  76 if ( $opt{'M'} && $h && $s ) {
  77     # Specify size in megabytes, not in cylinders
  78     $c = ($c*1024*2)/($h*$s);
  79 }
  80
  81 $is_open = 0;
  82
  83 if ( $c == 0 && $file ne '' ) {
  84     $len = 0;
  85     if ( sysopen(OUTPUT, $file, O_RDWR, 0666) ) {
  86         $is_open = 1;
  87
  88         if ( (@filestat = stat(OUTPUT)) && S_ISREG($filestat[2]) ) {
  89             $len = $filestat[7] >> 9;
  90         } elsif ( $is_linux && S_ISBLK($filestat[2]) ) {
  91             $blksize = pack("L!", 0);
  92             if ( ioctl(OUTPUT, $BLKGETSIZE, $blksize) == 0 ) {
  93                 $len = unpack("L!", $blksize); # In 512-byte sectors!
  94             }
  95         }
  96     }
  97
  98     if ( !$len ) {
  99         print STDERR "$0: $file: don't know how to determine the size of this device\n";
 100         exit 1;
 101     }
 102
 103     $c = $len/($h*$s);
 104 }
 105
 106 if ( $file eq '' || $c < 1 || $c > 1024 ||
 107      $h < 1 || $h > 256 || $s < 1 || $s > 63 ) {
 108     print STDERR "Usage: $0 [-doFMz4] file c h s (max: 1024 256 63)\n";
 109     print STDERR "    -d    add DOSEMU header\n";
 110     print STDERR "    -o    print filesystem offset to stdout\n";
 111     print STDERR "    -F    format partition as FAT32\n";
 112     print STDERR "    -M    \"c\" argument is megabytes, calculate cylinders\n";
 113     print STDERR "    -z    use zipdisk geometry (h=64 s=32)\n";
 114     print STDERR "    -4    use partition entry 4 (standard for zipdisks)\n";
 115     exit 1;
 116 }
 117
 118 $cylsize = $h*$s*512;
 119
 120 if ( !$is_open ) {
 121     sysopen(OUTPUT, $file, O_CREAT|O_RDWR|O_TRUNC, 0666)
 122         or die "$0: Cannot open: $file\n";
 123 }
 124 binmode OUTPUT;
 125
 126 # Print out DOSEMU header, if requested
 127 if ( $opt{'d'} ) {
 128     $emuhdr = "DOSEMU\0" . pack("VVVV", $h, $s, $c, 128);
 129     $emuhdr .= "\0" x (128 - length($emuhdr));
 130     print OUTPUT $emuhdr;
 131 }
 132
 133 # Print the MBR and partition table
 134 $mbr = '';
 135 while ( $line = <DATA> ) {
 136     chomp $line;
 137     foreach $byte ( split(/\s+/, $line) ) {
 138         $mbr .= chr(hex($byte));
 139     }
 140 }
 141 if ( length($mbr) > 446 ) {
 142     die "$0: Bad MBR code\n";
 143 }
 144
 145 $mbr .= "\0" x (446 - length($mbr));
 146
 147 print OUTPUT $mbr;
 148
 149 # Print partition table
 150 $psize = $c*$h*$s-$s;
 151 $bhead   = ($h > 1) ? 1 : 0;
 152 $bsect   = 1;
 153 $bcyl    = ($h > 1) ? 0 : 1;
 154 $ehead   = $h-1;
 155 $esect   = $s + ((($c-1) & 0x300) >> 2);
 156 $ecyl    = ($c-1) & 0xff;
 157 if ( $psize > 65536 ) {
 158     $fstype = 0x06;
 159 } else {
 160     $fstype = 0x04;
 161 }
 162 for ( $i = 1 ; $i <= 4 ; $i++ ) {
 163     if ( $i == $pentry ) {
 164         print OUTPUT pack("CCCCCCCCVV", 0x80, $bhead, $bsect, $bcyl, $fstype,
 165                           $ehead, $esect, $ecyl, $s, $psize);
 166     } else {
 167         print OUTPUT "\0" x 16;
 168     }
 169 }
 170 print OUTPUT "\x55\xaa";
 171
 172 # Output blank file
 173 $totalsize = $c*$h*$s;
 174 $tracks    = $c*$h;
 175
 176 $track = "\0" x (512*$s);
 177
 178 # Print fractional track
 179 print OUTPUT "\0" x (512 * ($s-1));
 180
 181 for ( $i = 1 ; $i < $tracks ; $i++ ) {
 182     print OUTPUT $track;
 183 }
 184
 185 # Print mtools temp file
 186 $n = 0;
 187 while ( !defined($tmpdir) ) {
 188     $tmpdir = "/tmp/mkdiskimage.$$.".($n++);
 189     if ( !mkdir($tmpdir, 0700) ) {
 190         die "$0: Failed to make temp directory: $tmpdir\n"
 191             if ( $! != EEXIST );
 192         undef $tmpdir;
 193     }
 194 }
 195
 196 $cfgfile = $tmpdir.'/mtools.conf';
 197 $imglink = $tmpdir.'/disk.img';
 198 die "$0: Failed to create symlink $imglink\n"
 199     if ( !symlink(absolute_path($file), $imglink) );
 200
 201 $header_size = ($opt{'d'} ? 128 : 0);
 202
 203 # Start of filesystem
 204 $offset = $s*512 + $header_size;
 205
 206 # Start of partition table entry
 207 $pstart = $header_size + 446 + 16*($pentry-1);
 208
 209 open(MCONFIG, "> ${cfgfile}") or die "$0: Cannot make mtools config\n";
 210 print MCONFIG "drive z:\n";
 211 print MCONFIG "file=\"${imglink}\"\n";
 212 print MCONFIG "cylinders=${c}\n";
 213 print MCONFIG "heads=${h}\n";
 214 print MCONFIG "sectors=${s}\n";
 215 print MCONFIG "offset=${offset}\n";
 216 print MCONFIG "mformat_only\n";
 217 close(MCONFIG);
 218
 219 # Output the filesystem offset to stdout if appropriate
 220 if ( $opt{'o'} ) {
 221     print $offset, "\n";
 222 }
 223
 224 $ENV{'MTOOLSRC'} = $cfgfile;
 225 if ( $opt{'F'} ) {
 226     system('mformat', '-F', 'z:');
 227 } else {
 228     system('mformat', 'z:');
 229 }
 230
 231 # Clean up in /tmp
 232 unlink($cfgfile);
 233 unlink($imglink);
 234 rmdir($tmpdir);
 235
 236 # MTOOLS doesn't write the bsHiddenSecs field correctly
 237 seek(OUTPUT, $offset + 0x1c, 0);
 238 print OUTPUT pack("V", ($offset-$header_size)>>9);
 239
 240 # Set the partition type
 241 if ( $opt{'F'} ) {
 242     $fstype = 0x0b;             # FAT32
 243 } else {
 244     if ( $psize > 65536 ) {
 245         $fstype = 0x06;         # FAT16 > 32MB
 246     } else {
 247         $fstype = 0x04;         # FAT16 <= 32MB
 248     }
 249     seek(OUTPUT, $offset + 0x36, 0);
 250     read(OUTPUT, $fsname, 8);
 251
 252     # FAT12: adjust partition type
 253     if ( $fsname eq 'FAT12   ' ) {
 254         $fstype = 0x01;         # FAT12
 255     }
 256 }
 257 seek(OUTPUT, $pstart+4, 0);
 258 print OUTPUT pack("C", $fstype);
 259
 260 flush OUTPUT;
 261
 262 # Just in case this is a block device, try to flush the partition table
 263 if ( $is_linux ) {
 264     ioctl(OUTPUT, $BLKRRPART, 0);
 265 };
 266
 267 exit 0;
 268 __END__