Fix Process resource leak in system metrics collection

Add process.waitFor() and process.destroyForcibly() in finally block
to prevent zombie processes when collecting system memory and network
metrics via Runtime.exec(). Also handle InterruptedException properly
by restoring the interrupt flag.

Affected files:
- SystemMetrics: memory info collection via 'free' command
- LinuxNetMetricManager: socket count collection via 'ss' command

Author: PDGGK

iotdb-core/metrics/interface/src/main/java/org/apache/iotdb/metrics/metricsets/net/LinuxNetMetricManager.java

@@ -218,8 +218,9 @@ private void updateNetStatus() {
 
     if (MetricLevel.higherOrEqual(MetricLevel.NORMAL, METRIC_CONFIG.getMetricLevel())) {
       // update socket num
+      Process process = null;
       try {
-        Process process = Runtime.getRuntime().exec(this.getConnectNumCmd);
+        process = Runtime.getRuntime().exec(this.getConnectNumCmd);
         StringBuilder result = new StringBuilder();
         try (BufferedReader input =
             new BufferedReader(new InputStreamReader(process.getInputStream()))) {
@@ -228,9 +229,17 @@ private void updateNetStatus() {
             result.append(line);
           }
         }
+        process.waitFor();
         this.connectionNum = Integer.parseInt(result.toString().trim());
       } catch (IOException e) {
         LOGGER.error("Failed to get socket num", e);
+      } catch (InterruptedException e) {
+        LOGGER.error("Interrupted while waiting for socket num command", e);
+        Thread.currentThread().interrupt();
+      } finally {
+        if (process != null) {
+          process.destroyForcibly();
+        }
       }
     }
   }

iotdb-core/metrics/interface/src/main/java/org/apache/iotdb/metrics/metricsets/system/SystemMetrics.java

@@ -217,8 +217,9 @@ private void updateLinuxSystemMemInfo() {
     long time = System.currentTimeMillis();
     if (time - lastUpdateTime > MetricConstant.UPDATE_INTERVAL) {
       lastUpdateTime = time;
+      Process process = null;
       try {
-        Process process = runtime.exec(getSystemMemoryCommand);
+        process = runtime.exec(getSystemMemoryCommand);
         StringBuilder result = new StringBuilder();
         try (BufferedReader input =
             new BufferedReader(new InputStreamReader(process.getInputStream()))) {
@@ -227,6 +228,7 @@ private void updateLinuxSystemMemInfo() {
             result.append(line).append("\n");
           }
         }
+        process.waitFor();
         String[] lines = result.toString().trim().split("\n");
         // if failed to get result
         if (lines.length >= 2) {
@@ -240,6 +242,13 @@ private void updateLinuxSystemMemInfo() {
         }
       } catch (IOException e) {
         logger.debug("Failed to get memory, because ", e);
+      } catch (InterruptedException e) {
+        logger.debug("Interrupted while waiting for memory command", e);
+        Thread.currentThread().interrupt();
+      } finally {
+        if (process != null) {
+          process.destroyForcibly();
+        }
       }
     }
   }