Fix potential leaks in executePipedCommands (apache#12478)

Author: abh1sar

utils/src/main/java/com/cloud/utils/script/Script.java

@@ -39,9 +39,11 @@
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.stream.Collectors;
 
 import org.apache.cloudstack.utils.security.KeyStoreUtils;
+import org.apache.commons.collections.CollectionUtils;
 import org.apache.commons.io.IOUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -729,13 +731,31 @@ public static int executeCommandForExitValue(String... command) {
         return executeCommandForExitValue(0, command);
     }
 
+    private static void cleanupProcesses(AtomicReference<List<Process>> processesRef) {
+        List<Process> processes = processesRef.get();
+        if (CollectionUtils.isNotEmpty(processes)) {
+            for (Process process : processes) {
+                if (process == null) {
+                    continue;
+                }
+                LOGGER.trace(String.format("Cleaning up process [%s] from piped commands.", process.pid()));
+                IOUtils.closeQuietly(process.getErrorStream());
+                IOUtils.closeQuietly(process.getOutputStream());
+                IOUtils.closeQuietly(process.getInputStream());
+                process.destroyForcibly();
+            }
+        }
+    }
+
     public static Pair<Integer, String> executePipedCommands(List<String[]> commands, long timeout) {
         if (timeout <= 0) {
             timeout = DEFAULT_TIMEOUT;
         }
+        final AtomicReference<List<Process>> processesRef = new AtomicReference<>();
         Callable<Pair<Integer, String>> commandRunner = () -> {
             List<ProcessBuilder> builders = commands.stream().map(ProcessBuilder::new).collect(Collectors.toList());
             List<Process> processes = ProcessBuilder.startPipeline(builders);
+            processesRef.set(processes);
             Process last = processes.get(processes.size()-1);
             try (BufferedReader reader = new BufferedReader(new InputStreamReader(last.getInputStream()))) {
                 String line;
@@ -762,6 +782,8 @@ public static Pair<Integer, String> executePipedCommands(List<String[]> commands
             result.second(ERR_TIMEOUT);
         } catch (InterruptedException | ExecutionException e) {
             LOGGER.error("Error executing piped commands", e);
+        } finally {
+            cleanupProcesses(processesRef);
         }
         return result;
     }