Minor auto_restore_wifi tweaks (#5143)

* Try to make sure restoreWifiAsync eventually sends a NetworkConnected
event...

re: #5109

* Take a page from @shermp's book, and make sure wpa_supplicant managed to
connect to the AP before acquiring an IP.
Tear down WiFi modules in case of failure.
c.f., https://github.com/shermp/Kobo-UNCaGED/pull/21

* Don't let restore-wifi-async.sh enable WiFi behind our back when we're
killing it to start Nickel...

* Don't even call ping if there's no default gw

frontend/device/generic/device.lua

@@ -187,6 +187,7 @@ function Device:onPowerEvent(ev)
                 local network_manager = require("ui/network/manager")
                 if network_manager.wifi_was_on and G_reader_settings:isTrue("auto_restore_wifi") then
                     network_manager:restoreWifiAsync()
+                    network_manager:scheduleConnectivityCheck()
                 end
                 self:resume()
                 -- restore to previous rotation mode, if need be.

frontend/ui/network/manager.lua

@@ -15,6 +15,26 @@ function NetworkMgr:readNWSettings()
     self.nw_settings = LuaSettings:open(DataStorage:getSettingsDir().."/network.lua")
 end
 
+-- Used after restoreWifiAsync() to make sure we eventually send a NetworkConnected event, as a few things rely on it (KOSync, c.f. #5109).
+function NetworkMgr:connectivityCheck(iter)
+    -- Give up after a while...
+    if iter > 6 then
+        return
+    end
+
+    if NetworkMgr:isWifiOn() and NetworkMgr:isConnected() then
+        local Event = require("ui/event")
+        UIManager:broadcastEvent(Event:new("NetworkConnected"))
+        logger.info("WiFi successfully restored!")
+    else
+        UIManager:scheduleIn(2, function() NetworkMgr:connectivityCheck(iter + 1) end)
+    end
+end
+
+function NetworkMgr:scheduleConnectivityCheck()
+    UIManager:scheduleIn(2, function() NetworkMgr:connectivityCheck(1) end)
+end
+
 function NetworkMgr:init()
     -- On Kobo, kill WiFi if NetworkMgr:isWifiOn() and NOT NetworkMgr:isConnected()
     -- (i.e., if the launcher left the WiFi in an inconsistent state: modules loaded, but no route to gateway).
@@ -26,6 +46,7 @@ function NetworkMgr:init()
     self.wifi_was_on = G_reader_settings:isTrue("wifi_was_on")
     if self.wifi_was_on and G_reader_settings:isTrue("auto_restore_wifi") then
         self:restoreWifiAsync()
+        self:scheduleConnectivityCheck()
     end
 end
 
@@ -101,12 +122,23 @@ function NetworkMgr:isConnected()
     if Device:isAndroid() or Device:isCervantes() or Device:isPocketBook() then
         return self:isWifiOn()
     else
+        -- Pull the default gateway first, so we don't even try to ping anything if there isn't one...
+        local default_gw
+        local std_out = io.popen([[/sbin/route -n | awk '$4 == "UG" {print $2}' | tail -n 1]], "r")
+        if std_out then
+            default_gw = std_out:read("*all")
+            std_out:close()
+            if not default_gw or default_gw == "" then
+                return false
+            end
+        end
+
         -- `-c1` try only once; `-w2` wait 2 seconds
         -- NOTE: No -w flag available in the old busybox build used on Legacy Kindles...
         if Device:isKindle() and Device:hasKeyboard() then
-            return 0 == os.execute([[ping -c1 $(/sbin/route -n | awk '$4 == "UG" {print $2}' | tail -n 1)]])
+            return 0 == os.execute("ping -c1 " .. default_gw)
         else
-            return 0 == os.execute([[ping -c1 -w2 $(/sbin/route -n | awk '$4 == "UG" {print $2}' | tail -n 1)]])
+            return 0 == os.execute("ping -c1 -w2 " .. default_gw)
         end
     end
 end

platform/kobo/nickel.sh

@@ -22,7 +22,7 @@ unset OLDPWD EXT_FONT_DIR TESSDATA_PREFIX FROM_NICKEL STARDICT_DATA_DIR LC_ALL K
 # Make sure we kill the WiFi first, because nickel apparently doesn't like it if it's up... (cf. #1520)
 # NOTE: That check is possibly wrong on PLATFORM == freescale (because I don't know if the sdio_wifi_pwr module exists there), but we don't terribly care about that.
 if lsmod | grep -q sdio_wifi_pwr; then
-    killall udhcpc default.script wpa_supplicant 2>/dev/null
+    killall restore-wifi-async.sh enable-wifi.sh obtain-ip.sh udhcpc default.script wpa_supplicant 2>/dev/null
     [ "${WIFI_MODULE}" != "8189fs" ] && [ "${WIFI_MODULE}" != "8192es" ] && wlarm_le -i "${INTERFACE}" down
     ifconfig "${INTERFACE}" down
     # NOTE: Kobo's busybox build is weird. rmmod appears to be modprobe in disguise, defaulting to the -r flag...

platform/kobo/restore-wifi-async.sh

@@ -2,8 +2,25 @@
 
 RestoreWifi() {
     echo "[$(date)] restore-wifi-async.sh: Restarting WiFi"
+
     ./enable-wifi.sh
+
+    # Much like we do in the UI, ensure wpa_supplicant did its job properly, first.
+    # Pilfered from https://github.com/shermp/Kobo-UNCaGED/pull/21 ;)
+    wpac_timeout=0
+    while ! wpa_cli status | grep -q "wpa_state=COMPLETED"; do
+        # If wpa_supplicant hasn't connected within 10 seconds, assume it never will, and tear down WiFi
+        if [ ${wpac_timeout} -ge 40 ]; then
+            echo "[$(date)] restore-wifi-async.sh: Failed to connect to preferred AP!"
+            ./disable-wifi.sh
+            return 1
+        fi
+        usleep 250000
+        wpac_timeout=$((wpac_timeout + 1))
+    done
+
     ./obtain-ip.sh
+
     echo "[$(date)] restore-wifi-async.sh: Restarted WiFi"
 }