#!/usr/bin/perl -T

use File::Temp;

@ARGV == 2 or die "usage: mkdosfs-with-dir <dir> <dosfs image>\n";

my ($dir, $img) = map {
    m![^\w.+:/-]! and die "bad path $_\n";
    /(.*)/;
} @ARGV;

($<, $>) = ($>, $<);

-e $img or die "$img does not exist\n";
-w $img or die "you don't have the rights to write into $img\n";
-d $dir or die "$dir must be a directory\n";

%ENV = (PATH => '/bin:/sbin:/usr/bin:/usr/sbin');

sub __ { print @_, "\n"; system(@_) == 0 }

my $tmp_mnt = File::Temp::tempdir('/tmp/mkdosfs-with-dir-XXXX', CLEANUP => 1);
__ "mkdosfs $img" or die "mkdosfs failed\n";


$> = $<;

if (__ "mount -t vfat -o umask=0,loop $img $tmp_mnt") {
    my $err;
    __ "tar cC $dir --owner=root . | tar xC $tmp_mnt" or $err = "copying failed";
    __ "umount $tmp_mnt" or $err ||= "umount failed";
    !$err or die "$err\n";
}
print "succeded\n";