Update module after feedback

Looks like I can't decide on certain style preferences.

Not keen on using blank?, but I've used it before. Time to commit?

Also, fail_with has been fixed for aux and post since rapid7#8643. Use it!

Author: wvu

documentation/modules/auxiliary/gather/nis_bootparamd_domain.md

@@ -17,8 +17,19 @@ If the link is down, you can find it via the Wayback Machine.
 After that is done, install `bootparamd` however your OS provides it.
 
 Make sure you add a client to the `bootparams` file, which is usually at
-`/etc/bootparams`. The client should be added to `/etc/hosts` if it
-isn't already resolvable.
+`/etc/bootparams`.
+
+Here is an example `bootparams` file (courtesy of
+[@bcoles](https://github.com/bcoles)):
+
+```
+clientname root=nfsserver:/export/clientname/root
+```
+
+You can read the `bootparams(5)` man page for more info.
+
+Lastly, the client should be added to `/etc/hosts` if it isn't already
+resolvable.
 
 ## Options
 

modules/auxiliary/gather/nis_bootparamd_domain.rb

@@ -33,7 +33,7 @@ def initialize(info = {})
 
     register_options([
       OptEnum.new('PROTOCOL',  [true, 'Protocol to use', 'udp', %w{tcp udp}]),
-      OptAddress.new('CLIENT', [true, 'Client from target\'s bootparams file'])
+      OptAddress.new('CLIENT', [true, "Client from target's bootparams file"])
     ])
 
     register_advanced_options([
@@ -52,11 +52,9 @@ def run
         1       # Program Version: 1
       )
     rescue Rex::ConnectionError
-      print_error('Could not connect to portmapper')
-      return
+      fail_with(Failure::Unreachable, 'Could not connect to portmapper')
     rescue Rex::Proto::SunRPC::RPCError
-      print_error('Could not connect to bootparamd')
-      return
+      fail_with(Failure::Unreachable, 'Could not connect to bootparamd')
     end
 
     # Flavor: AUTH_NULL (0)
@@ -76,33 +74,30 @@ def run
         bootparam_whoami # Boot Parameters
       )
     rescue Rex::Proto::SunRPC::RPCError
-      print_error('Could not call bootparamd procedure')
-      return
+      fail_with(Failure::NotFound, 'Could not call bootparamd procedure')
     rescue Rex::Proto::SunRPC::RPCTimeout
-      print_error('Could not disclose NIS domain name (try another CLIENT?)')
-      return
+      fail_with(Failure::NotVulnerable,
+                'Could not disclose NIS domain name (try another CLIENT?)')
     ensure
       # Shut it down! Shut it down forever!
       sunrpc_destroy
     end
 
-    if res.nil?
-      print_error('Invalid response from server')
-      return
+    unless res
+      fail_with(Failure::Unknown, 'No response from server')
     end
 
     bootparams = begin
       Timeout.timeout(datastore['XDRTimeout']) do
         parse_bootparams(res)
       end
     rescue Timeout::Error
-      print_error('XDR decoding timed out (try increasing XDRTimeout?)')
-      return
+      fail_with(Failure::TimeoutExpired,
+                'XDR decoding timed out (try increasing XDRTimeout?)')
     end
 
-    if bootparams.nil? || bootparams.empty?
-      print_error('Could not parse bootparams')
-      return
+    if bootparams.blank?
+      fail_with(Failure::Unknown, 'Could not parse bootparams')
     end
 
     bootparams.each do |host, domain|