1 files changed, 51 insertions, 2 deletions

diff --git a/src/Plugins/Monitors/Net.hs b/src/Plugins/Monitors/Net.hs
index 768907c..b8adc74 100644
--- a/src/Plugins/Monitors/Net.hs
+++ b/src/Plugins/Monitors/Net.hs
@@ -13,12 +13,18 @@
 --
 -----------------------------------------------------------------------------
 
-module Plugins.Monitors.Net (startNet) where
+module Plugins.Monitors.Net (
+                        startNet
+                      , startDynNet
+                      ) where
 
 import Plugins.Monitors.Common
 
 import Data.IORef (IORef, newIORef, readIORef, writeIORef)
 import Data.Time.Clock (UTCTime, getCurrentTime, diffUTCTime)
+import Control.Monad (forM, filterM)
+import System.Directory (getDirectoryContents, doesFileExist)
+import System.FilePath ((</>))
 
 import qualified Data.ByteString.Lazy.Char8 as B
 
@@ -28,14 +34,39 @@ data NetDev = NA
 
 type NetDevRef = IORef (NetDev, UTCTime)
 
+-- The more information available, the better.
+-- Note that names don't matter. Therefore, if only the names differ,
+-- a compare evaluates to EQ while (==) evaluates to False.
+instance Ord NetDev where
+    compare NA NA              = EQ
+    compare NA _               = LT
+    compare _  NA              = GT
+    compare (NI _) (NI _)      = EQ
+    compare (NI _) (ND _ _ _)  = LT
+    compare (ND _ _ _) (NI _)  = GT
+    compare (ND _ x1 y1) (ND _ x2 y2) =
+        if downcmp /= EQ
+           then downcmp
+           else y1 `compare` y2
+      where downcmp = x1 `compare` x2
+
 netConfig :: IO MConfig
 netConfig = mkMConfig
     "<dev>: <rx>KB|<tx>KB"      -- template
     ["dev", "rx", "tx", "rxbar", "txbar"]     -- available replacements
 
+operstateDir :: String -> FilePath
+operstateDir d = "/sys/class/net" </> d </> "operstate"
+
+existingDevs :: IO [String]
+existingDevs = getDirectoryContents "/sys/class/net" >>= filterM isDev
+  where isDev d | d `elem` excludes = return False
+                | otherwise = doesFileExist (operstateDir d)
+        excludes = [".", "..", "lo"]
+
 isUp :: String -> IO Bool
 isUp d = do
-  operstate <- B.readFile $ "/sys/class/net/" ++ d ++ "/operstate"
+  operstate <- B.readFile (operstateDir d)
   return $ "up" == (B.unpack . head . B.lines) operstate
 
 readNetDev :: [String] -> IO NetDev
@@ -103,9 +134,27 @@ parseNet nref nd = do
 runNet :: NetDevRef -> String -> [String] -> Monitor String
 runNet nref i _ = io (parseNet nref i) >>= printNet
 
+parseNets :: [(NetDevRef, String)] -> IO [NetDev]
+parseNets = mapM $ \(ref, i) -> parseNet ref i
+
+runNets :: [(NetDevRef, String)] -> [String] -> Monitor String
+runNets refs _ = io (parseActive refs) >>= printNet
+    where parseActive refs' = parseNets refs' >>= return . selectActive
+          selectActive = maximum
+
 startNet :: String -> [String] -> Int -> (String -> IO ()) -> IO ()
 startNet i a r cb = do
   t0 <- getCurrentTime
   nref <- newIORef (NA, t0)
   _ <- parseNet nref i
   runM a netConfig (runNet nref i) r cb
+
+startDynNet :: [String] -> Int -> (String -> IO ()) -> IO ()
+startDynNet a r cb = do
+  devs <- existingDevs
+  refs <- forM devs $ \d -> do
+            t <- getCurrentTime
+            nref <- newIORef (NA, t)
+            _ <- parseNet nref d
+            return (nref, d)
+  runM a netConfig (runNets refs) r cb