Adjust the getenv API

The getenv call in sys/config was renamed to getenvs and now uses
the splat operator so that arrays don't have to be passed in. A
new function called getenv was added which takes a single argument
and returns a single value back (for ease of use).

lib/rex/post/meterpreter/extensions/stdapi/sys/config.rb

@@ -37,7 +37,7 @@ class Config
   # Returns a hash of requested environment variables, along with their values.
   # If a requested value doesn't exist in the response, then the value wasn't found.
   #
-  def getenv(var_names)
+  def getenvs(*var_names)
     request = Packet.create_request('stdapi_sys_config_getenv')
 
     var_names.each do |v|
@@ -56,6 +56,13 @@ class Config
     return result
   end
 
+  #
+  # Returns the value of a single requested environment variable name
+  #
+  def getenv(var_name)
+    getenvs(var_name)[var_name]
+  end
+
   #
   # Returns a hash of information about the remote computer.
   #

lib/rex/post/meterpreter/ui/console/command_dispatcher/stdapi/sys.rb

@@ -279,8 +279,11 @@ class Console::CommandDispatcher::Stdapi::Sys
     print_line("Server username: #{client.sys.config.getuid}")
   end
 
+  #
+  # Get the value of one or more environment variables from the target.
+  #
   def cmd_getenv(*args)
-    vars = client.sys.config.getenv(args)
+    vars = client.sys.config.getenvs(*args)
 
     if vars.length == 0
       print_error("None of the specified environment variables were found/set.")