execute shell script in ruby

Question

I want to execute the following shell script

system('echo "
    rdr pass on lo0 inet proto tcp from any to 192.168.99.1 port 80 -> 192.168.99.1 port 8080
    rdr pass on lo0 inet proto tcp from any to 192.168.99.1 port 443 -> 192.168.99.1 port 4443
    " | sudo pfctl -ef - > /dev/null 2>&1; echo "==> Fowarding Ports: 80 -> 8080, 443 -> 4443 & Enabling pf"'
)

This works fine, i now want to pass the IP address loaded from a YAML file, i tried the following

config.yaml

configs:
    use: 'home'
    office:
        public_ip: '192.168.99.2'
    home:
        public_ip: '192.168.99.1'

Vagrantfile

require 'yaml'

current_dir    = File.dirname(File.expand_path(__FILE__))
configs        = YAML.load_file("#{current_dir}/config.yaml")
vagrant_config = configs['configs'][configs['configs']['use']]

system('echo "
    rdr pass on lo0 inet proto tcp from any to '+vagrant_config['public_ip']+' port 80 -> '+vagrant_config['public_ip']+' port 8080
    rdr pass on lo0 inet proto tcp from any to '+vagrant_config['public_ip']+' port 443 -> '+vagrant_config['public_ip']+' port 4443
    " | sudo pfctl -ef - > /dev/null 2>&1; echo "==> Fowarding Ports: 80 -> 8080, 443 -> 4443 & Enabling pf"'
)

The second method does not work, nor it shows any error, can someone point me to the right direction, what i want is to read public_ip dynamically from config file or variable

Thanks

UPDATE 1

I get the following output

pfctl: Use of -f option, could result in flushing of rules
present in the main ruleset added by the system at startup.
See /etc/pf.conf for further details.

No ALTQ support in kernel
ALTQ related functions disabled
pfctl: pf already enabled

What can be possibly wrong?

Run pfctl with the '-v' option to get more verbose output. You may also want to try writing the rdr commands to a file and referencing that file as the '-f' option is to read from a file (piping may not work). — Darren Hicks
– Darren Hicks, Commented Apr 7, 2016 at 17:05
@SilverPhoenix I get 192.168.99.1, strangely it started working when i restarted — Ibrahim Azhar Armar
– Ibrahim Azhar Armar, Commented Apr 7, 2016 at 17:11

Darren Hicks · Accepted Answer · 2016-04-07 17:13:12Z

1

For troubleshooting purposes, it would be wise to output the command you're going to run prior to sending it out to system.

cmd = 'echo "
rdr pass on lo0 inet proto tcp from any to '+vagrant_config['public_ip']+' port 80 -> '+vagrant_config['public_ip']+' port 8080
rdr pass on lo0 inet proto tcp from any to '+vagrant_config['public_ip']+' port 443 -> '+vagrant_config['public_ip']+' port 4443
" | sudo pfctl -ef - > /dev/null 2>&1; echo "==> Fowarding Ports: 80 -> 8080, 443 -> 4443 & Enabling pf"'

puts "Command to run:\n\n#{cmd}"
system( cmd )

Then, it would be wise to make the output from the system command visible. To make sure you get this feedback, I suggest you replace

sudo pfctl -ef - > /dev/null 2>&1

with (adding '-v' for more verbose output - pfctl man page)

sudo pfctl -efv -

and then look for the output and/or error messages.

Then, once the bugs are sorted out, you can put it back into stealthy, quiet mode :D

Also, since you are running with sudo you'll need to make sure the shell you're running within has sudo privileges and also make sure you're not being prompted for a password unknowingly.

edited Apr 7, 2016 at 17:13

answered Apr 7, 2016 at 16:48

Darren Hicks

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3 Comments

Ibrahim Azhar Armar Over a year ago

It does show me password prompt, when i enter it, it works, do you see anything wrong with the syntax?

Ibrahim Azhar Armar Over a year ago

Updated my question with the output

Ibrahim Azhar Armar Over a year ago

Strangely it started working when i restarted, thanks anyway for the help

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