mkdiskimage

   1 #!/usr/bin/perl
   2 ## -----------------------------------------------------------------------
   3 ##
   4 ##   Copyright 2002-2004 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{'M'} ) {
  72     # Specify size in megabytes, not in cylinders
  73     $c = ($c*1024*2)/($h*$s);
  74 }
  75
  76 $is_open = 0;
  77
  78 if ( $c == 0 && $file ne '' ) {
  79     $len = 0;
  80     if ( sysopen(OUTPUT, $file, O_RDWR, 0666) ) {
  81         $is_open = 1;
  82
  83         if ( (@filestat = stat(OUTPUT)) && S_ISREG($filestat[2]) ) {
  84             $len = $filestat[7] >> 9;
  85         } elsif ( $is_linux && S_ISBLK($filestat[2]) ) {
  86             $blksize = pack("L!", 0);
  87             if ( ioctl(OUTPUT, $BLKGETSIZE, $blksize) == 0 ) {
  88                 $len = unpack("L!", $blksize); # In 512-byte sectors!
  89             }
  90         }
  91     }
  92
  93     if ( !$len ) {
  94         print STDERR "$0: $file: don't know how to determine the size of this device\n";
  95         exit 1;
  96     }
  97
  98     $c = $len/($h*$s);
  99 }
 100
 101 if ( $file eq '' || $c < 1 || $c > 1024 ||
 102      $h < 1 || $h > 256 || $s < 1 || $s > 63 ) {
 103     print STDERR "Usage: $0 [-doF4] file [c h s] (max: 1024 256 63)\n";
 104     print STDERR "    -d    add DOSEMU header\n";
 105     print STDERR "    -o    print filesystem offset to stdout\n";
 106     print STDERR "    -F    format partition as FAT32\n";
 107     print STDERR "    -M    \"c\" argument is megabytes, calculate cylinders\n";
 108     print STDERR "    -4    use partition entry 4 (standard for zipdisks)\n";
 109     exit 1;
 110 }
 111
 112 $cylsize = $h*$s*512;
 113
 114 if ( !$is_open ) {
 115     sysopen(OUTPUT, $file, O_CREAT|O_RDWR|O_TRUNC, 0666)
 116         or die "$0: Cannot open: $file\n";
 117 }
 118 binmode OUTPUT;
 119
 120 # Print out DOSEMU header, if requested
 121 if ( $opt{'d'} ) {
 122     $emuhdr = "DOSEMU\0" . pack("VVVV", $h, $s, $c, 128);
 123     $emuhdr .= "\0" x (128 - length($emuhdr));
 124     print OUTPUT $emuhdr;
 125 }
 126
 127 # Print the MBR and partition table
 128 $mbr = '';
 129 while ( $line = <DATA> ) {
 130     chomp $line;
 131     foreach $byte ( split(/\s+/, $line) ) {
 132         $mbr .= chr(hex($byte));
 133     }
 134 }
 135 if ( length($mbr) > 446 ) {
 136     die "$0: Bad MBR code\n";
 137 }
 138
 139 $mbr .= "\0" x (446 - length($mbr));
 140
 141 print OUTPUT $mbr;
 142
 143 # Print partition table
 144 $psize = $c*$h*$s-$s;
 145 $bhead   = ($h > 1) ? 1 : 0;
 146 $bsect   = 1;
 147 $bcyl    = ($h > 1) ? 0 : 1;
 148 $ehead   = $h-1;
 149 $esect   = $s + ((($c-1) & 0x300) >> 2);
 150 $ecyl    = ($c-1) & 0xff;
 151 if ( $psize > 65536 ) {
 152     $fstype = 0x06;
 153 } else {
 154     $fstype = 0x04;
 155 }
 156 for ( $i = 1 ; $i <= 4 ; $i++ ) {
 157     if ( $i == $pentry ) {
 158         print OUTPUT pack("CCCCCCCCVV", 0x80, $bhead, $bsect, $bcyl, $fstype,
 159                           $ehead, $esect, $ecyl, $s, $psize);
 160     } else {
 161         print OUTPUT "\0" x 16;
 162     }
 163 }
 164 print OUTPUT "\x55\xaa";
 165
 166 # Output blank file
 167 $totalsize = $c*$h*$s;
 168 $tracks    = $c*$h;
 169
 170 $track = "\0" x (512*$s);
 171
 172 # Print fractional track
 173 print OUTPUT "\0" x (512 * ($s-1));
 174
 175 for ( $i = 1 ; $i < $tracks ; $i++ ) {
 176     print OUTPUT $track;
 177 }
 178
 179 # Print mtools temp file
 180 $n = 0;
 181 while ( !defined($tmpdir) ) {
 182     $tmpdir = "/tmp/mkdiskimage.$$.".($n++);
 183     if ( !mkdir($tmpdir, 0700) ) {
 184         die "$0: Failed to make temp directory: $tmpdir\n"
 185             if ( $! != EEXIST );
 186         undef $tmpdir;
 187     }
 188 }
 189
 190 $cfgfile = $tmpdir.'/mtools.conf';
 191 $imglink = $tmpdir.'/disk.img';
 192 die "$0: Failed to create symlink $imglink\n"
 193     if ( !symlink(absolute_path($file), $imglink) );
 194
 195 $header_size = ($opt{'d'} ? 128 : 0);
 196
 197 # Start of filesystem
 198 $offset = $s*512 + $header_size;
 199
 200 # Start of partition table entry
 201 $pstart = $header_size + 446 + 16*($pentry-1);
 202
 203 open(MCONFIG, "> ${cfgfile}") or die "$0: Cannot make mtools config\n";
 204 print MCONFIG "drive z:\n";
 205 print MCONFIG "file=\"${imglink}\"\n";
 206 print MCONFIG "cylinders=${c}\n";
 207 print MCONFIG "heads=${h}\n";
 208 print MCONFIG "sectors=${s}\n";
 209 print MCONFIG "offset=${offset}\n";
 210 print MCONFIG "mformat_only\n";
 211 close(MCONFIG);
 212
 213 # Output the filesystem offset to stdout if appropriate
 214 if ( $opt{'o'} ) {
 215     print $offset, "\n";
 216 }
 217
 218 $ENV{'MTOOLSRC'} = $cfgfile;
 219 if ( $opt{'F'} ) {
 220     system('mformat', '-F', 'z:');
 221 } else {
 222     system('mformat', 'z:');
 223 }
 224
 225 # Clean up in /tmp
 226 unlink($cfgfile);
 227 unlink($imglink);
 228 rmdir($tmpdir);
 229
 230 # MTOOLS doesn't write the bsHiddenSecs field correctly
 231 seek(OUTPUT, $offset + 0x1c, 0);
 232 print OUTPUT pack("V", ($offset-$header_size)>>9);
 233
 234 # Set the partition type
 235 if ( $opt{'F'} ) {
 236     $fstype = 0x0b;             # FAT32
 237 } else {
 238     if ( $psize > 65536 ) {
 239         $fstype = 0x06;         # FAT16 > 32MB
 240     } else {
 241         $fstype = 0x04;         # FAT16 <= 32MB
 242     }
 243     seek(OUTPUT, $offset + 0x36, 0);
 244     read(OUTPUT, $fsname, 8);
 245
 246     # FAT12: adjust partition type
 247     if ( $fsname eq 'FAT12   ' ) {
 248         $fstype = 0x01;         # FAT12
 249     }
 250 }
 251 seek(OUTPUT, $pstart+4, 0);
 252 print OUTPUT pack("C", $fstype);
 253
 254 flush OUTPUT;
 255
 256 # Just in case this is a block device, try to flush the partition table
 257 if ( $is_linux ) {
 258     ioctl(OUTPUT, $BLKRRPART, 0);
 259 };
 260
 261 exit 0;
 262 __END__
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