From 5a0deeb636063a42b48f064b475a3899fde57c34 Mon Sep 17 00:00:00 2001
From: Jose Antonio Ortega Ruiz <jao@gnu.org>
Date: Sun, 15 Apr 2012 05:00:49 +0200
Subject: Net: distinguishing between faulty and not active interfaces

---
 src/Plugins/Monitors/Net.hs | 106 ++++++++++++++++++--------------------------
 1 file changed, 42 insertions(+), 64 deletions(-)

diff --git a/src/Plugins/Monitors/Net.hs b/src/Plugins/Monitors/Net.hs
index 96a68c3..768907c 100644
--- a/src/Plugins/Monitors/Net.hs
+++ b/src/Plugins/Monitors/Net.hs
@@ -1,7 +1,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Plugins.Monitors.Net
--- Copyright   :  (c) 2011 Jose Antonio Ortega Ruiz
+-- Copyright   :  (c) 2011, 2012 Jose Antonio Ortega Ruiz
 --                (c) 2007-2010 Andrea Rossato
 -- License     :  BSD-style (see LICENSE)
 --
@@ -22,15 +22,9 @@ import Data.Time.Clock (UTCTime, getCurrentTime, diffUTCTime)
 
 import qualified Data.ByteString.Lazy.Char8 as B
 
-data OperState = Up | Down
-    deriving (Eq, Show, Read)
-
 data NetDev = NA
-            | ND { netDev :: String
-                 , netRx :: Float
-                 , netTx :: Float
-                 , netOperState :: OperState
-                 } deriving (Eq,Show,Read)
+            | NI String
+            | ND String Float Float deriving (Eq,Show,Read)
 
 type NetDevRef = IORef (NetDev, UTCTime)
 
@@ -39,55 +33,38 @@ netConfig = mkMConfig
     "<dev>: <rx>KB|<tx>KB"      -- template
     ["dev", "rx", "tx", "rxbar", "txbar"]     -- available replacements
 
--- Given a list of indexes, take the indexed elements from a list.
-getNElements :: [Int] -> [a] -> [a]
-getNElements ns as = map (as!!) ns
-
--- Split into words, with word boundaries indicated by the given predicate.
--- Drops delimiters.  Duplicates 'Data.List.Split.wordsBy'.
---
--- > map (wordsBy (`elem` " :")) ["lo:31174097 31174097", "eth0:  43598 88888"]
---
--- will become @[["lo","31174097","31174097"], ["eth0","43598","88888"]]@
-wordsBy :: (a -> Bool) -> [a] -> [[a]]
-wordsBy f s = case dropWhile f s of
-    [] -> []
-    s' -> w : wordsBy f s'' where (w, s'') = break f s'
-
-readNetDev :: [String] -> NetDev
-readNetDev [] = NA
-readNetDev xs =
-    ND (head xs) (r (xs !! 1)) (r (xs !! 2)) Down
-       where r s | s == "" = 0
-                 | otherwise = read s / 1024
-
-
-parseOperState :: String -> OperState
-parseOperState state | state == "down" = Down
-                     | otherwise       = Up
-
-fillOperState :: NetDev -> IO NetDev
-fillOperState (ND d r t _) = do
-        operstate <- B.readFile $ "/sys/class/net/" ++ d ++ "/operstate"
-        return (ND d r t (parseOperState $ (B.unpack . head . B.lines) operstate))
-
-fillOperState NA = return NA
-
-fileNet :: IO [NetDev]
-fileNet = do 
-    devs <- netParser `fmap` B.readFile "/proc/net/dev"
-    mapM fillOperState devs
+isUp :: String -> IO Bool
+isUp d = do
+  operstate <- B.readFile $ "/sys/class/net/" ++ d ++ "/operstate"
+  return $ "up" == (B.unpack . head . B.lines) operstate
+
+readNetDev :: [String] -> IO NetDev
+readNetDev (d:x:y:_) = do
+  up <- isUp d
+  return (if up then ND d (r x) (r y) else NI d)
+    where r s | s == "" = 0
+              | otherwise = read s / 1024
+
+readNetDev _ = return NA
+
+netParser :: B.ByteString -> IO [NetDev]
+netParser = mapM (readNetDev . splitDevLine) . readDevLines
+  where readDevLines = drop 2 . B.lines
+        splitDevLine = selectCols . wordsBy (`elem` " :") . B.unpack
+        selectCols cols = map (cols!!) [0,1,9]
+        wordsBy f s = case dropWhile f s of
+          [] -> []
+          s' -> w : wordsBy f s'' where (w, s'') = break f s'
 
 findNetDev :: String -> IO NetDev
 findNetDev dev = do
-  nds <- fileNet
-  case filter (\d -> netDev d == dev) nds of
+  nds <- B.readFile "/proc/net/dev" >>= netParser
+  case filter isDev nds of
     x:_ -> return x
     _ -> return NA
-
-netParser :: B.ByteString -> [NetDev]
-netParser =
-    map (readNetDev . getNElements [0,1,9] . wordsBy (`elem` " :") . B.unpack) . drop 2 . B.lines
+  where isDev (ND d _ _) = d == dev
+        isDev (NI d) = d == dev
+        isDev NA = False
 
 formatNet :: Float -> Monitor (String, String)
 formatNet d = do
@@ -100,13 +77,13 @@ formatNet d = do
 
 printNet :: NetDev -> Monitor String
 printNet nd =
-    case nd of
-         ND d r t o -> case o of
-            Up -> do (rx, rb) <- formatNet r
-                     (tx, tb) <- formatNet t
-                     parseTemplate [d,rx,tx,rb,tb]
-            Down -> return ""
-         NA -> return ""
+  case nd of
+    ND d r t -> do
+        (rx, rb) <- formatNet r
+        (tx, tb) <- formatNet t
+        parseTemplate [d,rx,tx,rb,tb]
+    NI _ -> return ""
+    NA -> return "N/A"
 
 parseNet :: NetDevRef -> String -> IO NetDev
 parseNet nref nd = do
@@ -116,10 +93,11 @@ parseNet nref nd = do
   writeIORef nref (n1, t1)
   let scx = realToFrac (diffUTCTime t1 t0)
       scx' = if scx > 0 then scx else 1
-      netRate f da db = takeDigits 2 $ (f db - f da) / scx'
-      diffRate NA _ = NA
-      diffRate _ NA = NA
-      diffRate da db = ND nd (netRate netRx da db) (netRate netTx da db) (netOperState db)
+      rate da db = takeDigits 2 $ (db - da) / scx'
+      diffRate (ND d ra ta) (ND _ rb tb) = ND d (rate ra rb) (rate ta tb)
+      diffRate (NI d) _ = NI d
+      diffRate _ (NI d) = NI d
+      diffRate _ _ = NA
   return $ diffRate n0 n1
 
 runNet :: NetDevRef -> String -> [String] -> Monitor String
-- 
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