sub checkfile {
 my $file = shift;
 my $duration = shift || 10;
 eval {
   local $SIG{ALRM} = sub { die "file access to $file failed\n" };

   alarm $duration;

   do {
     eval {
        die "cannot access $file\n" unless -e $file;
     };
     sleep 1 if $@;
   } until !$@;
   
   alarm 0;
 };

 return if $@;
 return 1 unless $@;
}