#!/usr/local/perl -w
use strict;
use File::Find::Rule;

use constant FMT => " %5s  %-10s  %-60s\n";

my @userdir = do {
	opendir my $dh, "/home";
	grep +($_ ne '.' and $_ ne '..' and -d "/home/$_"), readdir $dh;
};

my %uid = map { (getpwnam $_)[0,2] } @userdir;

my $i = 0;

my @offending = map {
    File::Find::Rule
        ->exec(sub { $i++ % 80 or print STDERR '.'; 1 })
        ->not_uid($uid{$_})
        ->in("/home/$_");
} keys %uid;

print STDERR "\n";

printf FMT, 'UID', 'User', 'Offending file';
print "-" x 80 . "\n";

my %uname = reverse %uid;

for (@offending) {
    my $fuid = +(stat)[4];
    warn "Can't stat $_\n", next if not defined $fuid;
    $uname{$fuid} = getpwuid($fuid)
        unless exists $uname{$fuid};
    printf FMT, $fuid, $uname{$fuid}, $_;
}