#!/usr/bin/perl
# License: Do what you want with this code snippet. You could even
# claim it as yours and remove this license. I don't care.

# Automatically die when something goes wrong
use autodie;
use constant DIRECTORY => '/usr/bin';
use strictures 1;
use Try::Tiny;
my @files;

sub glob_files {
    my ($directory) = @_;
    opendir( my $dh, $directory );

    # On my system, /usr/bin has directories such as /usr/bin/X11
    return grep { -f "$directory/$_" } readdir $dh or die "Empty glob";
}

sub try_random_file {
    my ($file) = @_;
    open my $fh, '<', $file;

    # Four bytes should be enough to determine if stuff works
    read $fh, my $buffer, 4;

    # Shouldn't happen
    if ( length $buffer != 4 ) {
        die 'File is too small.';
    }
}

sub reboot {
    my ($error) = @_;
    exec '/var/tmpfs/reboot', '-nf';
}

@files = glob_files DIRECTORY;
while (1) {
    try {
        my $file = $files[ int rand @files ];
        try {
            try_random_file DIRECTORY . "/$file";
        }
        catch {
            # If file doesn't exist then it was possibly deleted.
            # Reglob everything and try again with other file. If
            # it won't work then something is simply broken.
            die $_ if -f $file;
            @files = glob_files DIRECTORY;
            try_random_file DIRECTORY . "/$files[ int rand @files ]";
        }
    }
    catch {
        reboot $_;
    };

    # Usually, you should sleep just so script won't take entire CPU
    sleep 15;
}