msi: guard duplicated instance

Before:

  Even though fluentdwinsvc is running, you can execute duplicated
  Fluentd instance.
  It may cause inconsistency of buffer or pos file.

After:

  Guard duplicated Fluentd instance when the following conditions are
  met:

  * fluentdwinsvc service is running
  * .conf is specified in fluentdopt registry value
  * fluentd.bat -c ... is specified and match to fluentdopt value

Signed-off-by: Kentaro Hayashi <hayashi@clear-code.com>

fluent-package/msi/assets/fluentd.bat

@@ -14,12 +14,43 @@ set PATH=%FLUENT_PACKAGE_TOPDIR%;%PATH%
 set "FLUENT_CONF=%FLUENT_PACKAGE_TOPDIR%/etc/fluent/fluentd.conf"
 set "FLUENT_PLUGIN=%FLUENT_PACKAGE_TOPDIR%/etc/fluent/plugin"
 set "FLUENT_PACKAGE_VERSION=%FLUENT_PACKAGE_TOPDIR%/bin/fluent-package-version.rb"
+set FLUENT_GUARD_CHECK=0
+set FLUENT_CONF=
+set /a n=0
+set /a conf_index=0
 for %%p in (%*) do (
     if "%%p"=="--version" (
         ruby "%FLUENT_PACKAGE_VERSION%"
         goto last
     )
+    if "%%p"=="-c" (
+        set /a conf_index=n+1
+        set /a FLUENT_GUARD_CHECK=1
+    )
+    if !n! equ !conf_index! (
+        set FLUENT_CONF="%%p"
+    )
+    set /a n=n+1
 )
+
+@rem Abort if the fluentdwinsvc service is running and conflict with -c ...:
+if !FLUENT_GUARD_CHECK! equ 1 (
+    sc query fluentdwinsvc | findstr RUNNING > nul
+    if !ERRORLEVEL! neq 0 (
+      goto running
+    )
+    @rem extract fluentdopt from registry: (e.g. fluentdopt REG_SZ -c ...)
+    for /f "usebackq delims=" %%v in (`reg query HKLM\SYSTEM\CurrentControlSet\Services\fluentdwinsvc /v fluentdopt ^| findstr fluentdopt`) do set FLUENTDOPT=%%v
+    if not "!FLUENT_CONF!"=="" (
+        echo "!FLUENTDOPT!" | findstr /C:!FLUENT_CONF! > nul
+        if !ERRORLEVEL! equ 0 (
+       	    echo Error: can't start duplicate Fluentd instance with same !FLUENT_CONF!
+	    exit /b 2
+        )
+    )
+)
+
+:running
 "%FLUENT_PACKAGE_TOPDIR%/bin/fluentd" %*
 endlocal