Wireless: simple auto-detection of interface name

3 files changed, 14 insertions, 3 deletions

diff --git a/changelog.md b/changelog.md
index de7f14c..a2c16d9 100644
--- a/changelog.md
+++ b/changelog.md
@@ -6,6 +6,8 @@ _New features_
     Daniel Schüssler.
   - `ThermalZone` retries reading missing files, thanks to Reed Koser.
   - `TopProc` ignores kernel threads (see also [issue #369]).
+  - `Wireless` simple autodetection of wirless interface name (if set
+    to "").
 
 _Bug fixes_
 
diff --git a/readme.md b/readme.md
index 04d56ce..0cff8bf 100644
--- a/readme.md
+++ b/readme.md
@@ -769,8 +769,9 @@ something like:
 
 ### `Wireless Interface Args RefreshRate`
 
+- If set to "", the interface is looked up in /proc/net/wireless.
 - Aliases to the interface name with the suffix "wi": thus, `Wireless
-  "wlan0" []` can be used as `%wlan0wi%`
+  "wlan0" []` can be used as `%wlan0wi%`, and `Wireless "" []` as `%wi%`.
 - Args: default monitor arguments, plus:
   - `--quality-icon-pattern`: dynamic string for connection quality in `qualityipat`.
 - Variables that can be used with the `-t`/`--template` argument:
diff --git a/src/Plugins/Monitors/Wireless.hs b/src/Plugins/Monitors/Wireless.hs
index eeef9a9..9397e50 100644
--- a/src/Plugins/Monitors/Wireless.hs
+++ b/src/Plugins/Monitors/Wireless.hs
@@ -42,12 +42,14 @@ parseOpts argv =
 
 wirelessConfig :: IO MConfig
 wirelessConfig =
-  mkMConfig "<essid> <quality>" ["essid", "quality", "qualitybar", "qualityvbar", "qualityipat"]
+  mkMConfig "<essid> <quality>"
+            ["essid", "quality", "qualitybar", "qualityvbar", "qualityipat"]
 
 runWireless :: String -> [String] -> Monitor String
 runWireless iface args = do
   opts <- io $ parseOpts args
-  wi <- io $ getWirelessInfo iface
+  iface' <- if "" == iface then io findInterface else return iface
+  wi <- io $ getWirelessInfo iface'
   na <- getConfigValue naString
   let essid = wiEssid wi
       qlty = fromIntegral $ wiQuality wi
@@ -60,3 +62,9 @@ runWireless iface args = do
   qvb <- showVerticalBar qlty (qlty / 100)
   qipat <- showIconPattern (qualityIconPattern opts) (qlty / 100)
   parseTemplate [ep, q, qb, qvb, qipat]
+
+findInterface :: IO String
+findInterface = do
+  c <- readFile "/proc/net/wireless"
+  let nds = lines c
+  return $ if length nds > 2 then takeWhile (/= 'c') (nds!!2) else []