From 17416feb5efee528ca5e8a74d63c04f0d5e31bf4 Mon Sep 17 00:00:00 2001
From: dmiller <dmiller@e0a8ed71-7df4-0310-8962-fdc924857419>
Date: Thu, 16 Jan 2020 19:12:58 +0000
Subject: [PATCH] New outlib library for output-related functions

---
 CHANGELOG                    |  3 +++
 nselib/outlib.lua            | 49 ++++++++++++++++++++++++++++++++++++
 nselib/unittest.lua          |  1 +
 scripts/clock-skew.nse       | 23 ++---------------
 scripts/ssl-enum-ciphers.nse | 23 ++---------------
 5 files changed, 57 insertions(+), 42 deletions(-)
 create mode 100644 nselib/outlib.lua

diff --git a/CHANGELOG b/CHANGELOG
index 84ac822f9..d8cb59f06 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,8 @@
 #Nmap Changelog ($Id$); -*-text-*-
 
+o [NSE] New outlib library will consolidate functions related to NSE output,
+  both string formatting conventions and structured output. [Daniel Miller]
+
 o New XML output "hosthint" tag emitted during host discovery when a target is
   found to be up. This gives earlier notification than waiting for the
   hostgroup to finish all scan phases. [Paul Miseiko]
diff --git a/nselib/outlib.lua b/nselib/outlib.lua
new file mode 100644
index 000000000..c04eff8bc
--- /dev/null
+++ b/nselib/outlib.lua
@@ -0,0 +1,49 @@
+--- Helper functions for NSE script output
+--
+-- These functions are useful for ensuring output is consistently ordered
+-- between scans and following conventions for output formatting.
+--
+-- @author Daniel Miller
+-- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html
+-- @class module
+-- @name outlib
+
+local tableaux = require "tableaux"
+local keys = tableaux.keys
+
+local coroutine = require "coroutine"
+local wrap = coroutine.wrap
+local yield = coroutine.yield
+
+local table = require "table"
+local sort = table.sort
+
+local setmetatable = setmetatable
+local ipairs = ipairs
+
+local _ENV = {}
+
+--- Create a table that yields elements sorted by key when iterated over with pairs()
+--
+-- The returned table is like a sorted view of the original table; it should be
+-- treated as read-only, and any new data should be added to the original table
+-- instead.
+--@param  t    The table whose data should be used
+--@return out  A table that can be passed to pairs() to get sorted results
+function sorted_by_key(t)
+  local out = {}
+  setmetatable(out, {
+    __pairs = function(_)
+      local order = keys(t)
+      sort(order)
+      return wrap(function()
+        for i,k in ipairs(order) do
+          yield(k, t[k])
+        end
+      end)
+    end
+  })
+  return out
+end
+
+return _ENV
diff --git a/nselib/unittest.lua b/nselib/unittest.lua
index ef50f5c8f..ac90c3182 100644
--- a/nselib/unittest.lua
+++ b/nselib/unittest.lua
@@ -105,6 +105,7 @@ local libs = {
 "omp2",
 "openssl",
 "ospf",
+"outlib",
 "packet",
 "pcre",
 "pgsql",
diff --git a/scripts/clock-skew.nse b/scripts/clock-skew.nse
index 33701cb7d..0b123fdea 100644
--- a/scripts/clock-skew.nse
+++ b/scripts/clock-skew.nse
@@ -3,6 +3,7 @@ local datetime = require "datetime"
 local formulas = require "formulas"
 local math = require "math"
 local nmap = require "nmap"
+local outlib = require "outlib"
 local stdnse = require "stdnse"
 local table = require "table"
 
@@ -126,26 +127,6 @@ local function sorted_keys(t)
   return ret
 end
 
---- Return a table that yields elements sorted by key when iterated over with pairs()
---  Should probably put this in a formatting library later.
---  Depends on keys() function defined above.
---@param  t    The table whose data should be used
---@return out  A table that can be passed to pairs() to get sorted results
-function sorted_by_key(t)
-  local out = {}
-  setmetatable(out, {
-    __pairs = function(_)
-      local order = sorted_keys(t)
-      return coroutine.wrap(function()
-        for i,k in ipairs(order) do
-          coroutine.yield(k, t[k])
-        end
-      end)
-    end
-  })
-  return out
-end
-
 postaction = function()
   local skews = nmap.registry.clock_skews
 
@@ -184,7 +165,7 @@ postaction = function()
   end
 
   if next(out) then
-    return sorted_by_key(out)
+    return outlib.sorted_by_key(out)
   end
 end
 
diff --git a/scripts/ssl-enum-ciphers.nse b/scripts/ssl-enum-ciphers.nse
index 690f04891..591a576a3 100644
--- a/scripts/ssl-enum-ciphers.nse
+++ b/scripts/ssl-enum-ciphers.nse
@@ -1,6 +1,7 @@
 local coroutine = require "coroutine"
 local math = require "math"
 local nmap = require "nmap"
+local outlib = require "outlib"
 local shortport = require "shortport"
 local sslcert = require "sslcert"
 local stdnse = require "stdnse"
@@ -1070,26 +1071,6 @@ portrule = function (host, port)
   return shortport.ssl(host, port) or sslcert.getPrepareTLSWithoutReconnect(port)
 end
 
---- Return a table that yields elements sorted by key when iterated over with pairs()
---  Should probably put this in a formatting library later.
---  Depends on keys() function defined above.
---@param  t    The table whose data should be used
---@return out  A table that can be passed to pairs() to get sorted results
-function sorted_by_key(t)
-  local out = {}
-  setmetatable(out, {
-    __pairs = function(_)
-      local order = sorted_keys(t)
-      return coroutine.wrap(function()
-        for i,k in ipairs(order) do
-          coroutine.yield(k, t[k])
-        end
-      end)
-    end
-  })
-  return out
-end
-
 action = function(host, port)
 
   if not have_ssl then
@@ -1129,5 +1110,5 @@ action = function(host, port)
   end
   results["least strength"] = least
 
-  return sorted_by_key(results)
+  return outlib.sorted_by_key(results)
 end