miZy_mmc_add_partitions

#!/usr/bin/perl

#https://en.wikipedia.org/wiki/Master_boot_record#Sector_layout
#https://en.wikipedia.org/wiki/Master_boot_record#PTE


sub USAGE() { warn qq{
output raw mmc image

    MMC=1 img_name=firmwares/mizy_mmc_image.bin  ./miZy_spi_image_builder 2>&1 | \
	tee /tmp/miZy_spi_image_builder.log

add one partiotion and write some readme info there

    ./miZy_mmc_add_partitions firmwares/mizy_mmc_image.bin 8x8 /tmp/miZy_spi_image_builder.log

NOTE

fdisk 

    fdisk mizy_mmc_image.bin -l

    Disk mizy_mmc_image.bin: 16 MB, 16777216 bytes
    2 heads, 8 sectors/track, 2048 cylinders, total 32768 sectors
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0xdeedfeed

             Device Boot      Start         End      Blocks   Id  System
    mizy_mmc_image.bin1           16384       32767        8192   83  Linux

usage image as nbd device

    qemu-nbd -c /dev/nbd0 mizy_mmc_image.bin

    blkid | grep miZy
    /dev/nbd0p1: SEC_TYPE="msdos" LABEL="miZy_Info" UUID="FEED-DEED" TYPE="vfat"

    fdisk -l /dev/nbd0
    ....

    mount /dev/nbd0p1 mount_point_mmc_part_1
    umount /dev/nbd0p1 

    qemu-nbd -d /dev/nbd0 

};
exit 0;
};


USAGE if ( join "" => @ARGV ) =~ /-{1,2}h(elp)?/;

our $fstype = $ENV{fstype};
    $fstype //= 'vfat';
    $fstype //= 'ext2';
our $mkfs = "mkfs.$fstype";

our $mizy_disk_id = "edfeedde"; # not change

our $part_end = join "" => qw/
00000000000000000000000000000000
00000000000000000000000000000000
00000000000000000000000000000000
55aa
/;

our %mbr = (

#~ 'def' => [
#~ "\x00"x440 . 
#~ pack "H*" => join "" => $mizy_disk_id => qw/
#~ 0000
#~ 00050501832524010040000000080000
#~ 00000000000000000000000000000000
#~ 00000000000000000000000000000000
#~ 00000000000000000000000000000000
#~ 55aa 
#~ / ]

# mbr + first part 8M offset + 8M size
'8x8' => [ 16384, 16384,
"\x00"x440 . 
pack "H*" => join "" => $mizy_disk_id => qw/
0000
00 00 11 3e 83 01 08 7c 00 40  00 00 00 40 00 00
/  => $part_end
]

);

#	  / 83h -linux / 0Ch - fat32 / 0Eh - fat16
#__======PT------........++++++++
#00050501832524010040000000080000
#		 |       '--------- Number of sectors in partition
#                 \_ LBA of first absolute sector in the partition
#         

#0x1000000 = 16777216
#16777216 / 512 = 32768

our $fname;
our $out_name = "+<" . ($fname = shift)
    if -f $ARGV[0];

    $out_name //= ">&STDOUT";

our $fsize  = defined $fname ?  -s $fname : 0;

open OUT, $out_name;
our $pos = sysseek OUT, 0, 0;


our $part_name = shift;
our $part_names = join " " => sort keys %mbr;

die "[e] undef part name: $part_name ( $part_names )\n"
    unless defined $mbr{ $part_name };

my $w = syswrite OUT, $mbr{$part_name}->[2];
warn "[i] write $w bytes to $pos pos in $out_name ($fsize bytes)\n";

#$pos = sysseek OUT, 0, 2;
our $part_offset=512*$mbr{$part_name}->[0];
our $part_size=512*$mbr{$part_name}->[1];

$pos = sysseek OUT, $part_offset , 0;

my $w = syswrite OUT, "\x00"x$part_size;

close OUT;

warn "[i] write $w to $pos pos in $out_name\n";
our $vol_name = "miZy_Info"; # not change
our $vol_id = "feeddeed"; # not change

our $loop_dev=`losetup --show -f -o $part_offset $fname`;
chomp $loop_dev;
warn "[i] loop dev '$loop_dev'\n";
our $tmp_dir = "/tmp/$vol_name.$$";

mkdir $tmp_dir;

our $args="";

$args = "-n $vol_name -i $vol_id"	if $fstype eq 'vfat';
$args = "-L $vol_name -U " .  sprintf("%s-%04x-%04x-%04x-%012x",
     $vol_id, 1,2,3,time ) 		if $fstype =~ m/ext/;

warn "[i] mkfs args $args\n";

`$mkfs $args $loop_dev`;
`mount $loop_dev $tmp_dir`;
`cat ./README.md > $tmp_dir/README.md`;
`cat ./LICENSE > $tmp_dir/LICENSE`;
`ln -s LICENSE '$tmp_dir/## hyphop ##' || cp '## hyphop ##' $tmp_dir`;

while ( $_ = shift @ARGV ) {
    if ( -f $_ ) {
	m{.+/};
	warn "[i] add $_ to $tmp_dir/$'\n";
	`cp "$_" "$tmp_dir/$'"`;
    }
}

`umount $loop_dev`;
`losetup -d $loop_dev`;

exec rmdir => $tmp_dir;

__END__

dd count=1 < /dev/mmcblk0 2>/dev/null | hd
00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000001b0  00 00 00 00 00 00 00 00  15 be 63 5c 00 00 00 00  |..........c\....|
000001c0  11 3e 83 01 08 7c 00 40  00 00 00 40 00 00 00 00  |.>...|.@...@....|
000001d0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000001f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 55 aa  |..............U.|
00000200