#!/bin/sh
# 

# Mac OSX Adblocker Script for IPv4
# Description: Blocks ads using system hosts file /private/etc/hosts, Ad-Domains would be redirected to 0.0.0.0
# Author: Daniel Hochleitner
# Created: 10.09.2015
# Use: sudo ./adblock_hosts.sh

# Get original hosts file from /private/etc/hosts
#
echo '!! Step 1: Get original hosts file'
# into current directory
if [ -f hosts_org.txt ]; then
  echo '--> original hosts file already saved in current directory';
else
  cp /private/etc/hosts hosts_org.txt
fi
# save into /private/etc/hosts_org
if [ -f /private/etc/hosts_org ]; then 
  echo '--> original hosts file already saved in /private/etc/hosts_org';
else
  sudo cp -p /private/etc/hosts /private/etc/hosts_org
  echo '--> saved hosts file into /private/etc/hosts_org'
fi

echo '!! Step 2: Get Adblock hosts files from WWW'
rm -fr www_hosts
mkdir www_hosts
cd www_hosts

# Host 1
curl -O https://adaway.org/hosts.txt
mv hosts.txt hosts1.txt
if [ -f hosts1.txt ]; then
  echo '--> adaway.org saved';
fi

# Host 2
curl -O http://hosts-file.net/.%5Cad_servers.txt
mv .%5Cad_servers.txt hosts2.txt
if [ -f hosts2.txt ]; then
  echo '--> hosts-file.net saved';
fi

# Host 3
curl -O http://winhelp2002.mvps.org/hosts.txt
mv hosts.txt hosts3.txt
if [ -f hosts3.txt ]; then
  echo '--> winhelp2002.mvps.org saved';
fi

# Host 4
curl -O "http://pgl.yoyo.org/adservers/serverlist.php?hostformat=hosts&showintro=0&mimetype=plaintext"
mv serverlist.php\?hostformat\=hosts\&showintro\=0\&mimetype\=plaintext hosts4.txt
if [ -f hosts4.txt ]; then
  echo '--> pgl.yoyo.org saved';
fi

# Host 5
curl -O http://www.malwaredomainlist.com/hostslist/hosts.txt
mv hosts.txt hosts5.txt
if [ -f hosts5.txt ]; then
  echo '--> malwaredomainlist saved';
fi

# Host 6
curl -O http://someonewhocares.org/hosts/zero/hosts
mv hosts hosts6.txt
if [ -f hosts6.txt ]; then
  echo '--> someonewhocares.org saved';
fi

# merge files into new host file
#
echo '!! Step 3: merge files into new host file'
cd ..

cat www_hosts/hosts1.txt >> hosts_new_temp.txt
cat www_hosts/hosts2.txt >> hosts_new_temp.txt
cat www_hosts/hosts3.txt >> hosts_new_temp.txt
cat www_hosts/hosts4.txt >> hosts_new_temp.txt
cat www_hosts/hosts5.txt >> hosts_new_temp.txt
cat www_hosts/hosts6.txt >> hosts_new_temp.txt

# Replace special entries
sed -i.bak '/localhost/d' hosts_new_temp.txt
sed -i.bak '/broadcasthost/d' hosts_new_temp.txt
sed -i.bak '/local/d' hosts_new_temp.txt
sed -i.bak '/piwik.org/d' hosts_new_temp.txt
sed -i.bak '/spclient.wg.spotify.com/d' hosts_new_temp.txt
sed -i.bak '/securemetrics.apple.com/d' hosts_new_temp.txt
sed -i.bak 's/127.0.0.1/0.0.0.0/' hosts_new_temp.txt

# build new hosts file
cat hosts_org.txt > hosts_new.txt
# special 0.0.0.0 entry
echo "# Special Entries" >> hosts_new.txt
echo "0.0.0.0    0.0.0.0    # fix for traceroute and netstat" >> hosts_new.txt
# adblock hosts entries
cat hosts_new_temp.txt >> hosts_new.txt

rm -f hosts_new_temp.txt*

# write new hosts file into system
echo '!! Step 4: write new hosts file into system'

echo '--> writing file...'
sudo cp hosts_new.txt /private/etc/hosts
chmod 644 /private/etc/hosts
echo '--> refresh DNS cache...'
dscacheutil -flushcache
sudo killall -HUP mDNSResponder
echo '!! Finished !!'