fix: close streams in LoggerContextAdmin.setConfigLocationUri

log4j-core-test/src/test/java/org/apache/logging/log4j/core/jmx/LoggerContextAdminSetConfigLocationUriTest.java

@@ -0,0 +1,81 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.logging.log4j.core.jmx;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import org.apache.logging.log4j.core.LoggerContext;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+/**
+ * Regression for stream ownership in {@link LoggerContextAdmin#setConfigLocationUri(String)}.
+ * The method buffers configuration bytes and closes the underlying File/URL stream before
+ * ConfigurationFactory runs.
+ */
+class LoggerContextAdminSetConfigLocationUriTest {
+
+    @TempDir
+    Path tempDir;
+
+    @Test
+    void setConfigLocationUri_loadsValidFileAndReconfigures() throws Exception {
+        final Path config = tempDir.resolve("log4j2-test.xml");
+        writeConfig(config, "C");
+
+        final LoggerContext ctx = new LoggerContext("jmx-admin-stream-test");
+        final LoggerContextAdmin admin = new LoggerContextAdmin(ctx, Runnable::run);
+
+        assertDoesNotThrow(
+                () -> admin.setConfigLocationUri(config.toAbsolutePath().toString()));
+        assertTrue(ctx.getConfiguration().getAppenders().containsKey("C"));
+    }
+
+    @Test
+    void setConfigLocationUri_fileUrlFormAlsoLoads() throws Exception {
+        final Path config = tempDir.resolve("log4j2-url.xml");
+        writeConfig(config, "FromUrl");
+
+        final LoggerContext ctx = new LoggerContext("jmx-admin-file-url-test");
+        final LoggerContextAdmin admin = new LoggerContextAdmin(ctx, Runnable::run);
+        final String fileUrl = config.toUri().toURL().toString();
+        assertDoesNotThrow(() -> admin.setConfigLocationUri(fileUrl));
+        assertTrue(ctx.getConfiguration().getAppenders().containsKey("FromUrl"));
+    }
+
+    @Test
+    void setConfigLocationUri_rejectsBlankLocation() {
+        final LoggerContext ctx = new LoggerContext("jmx-admin-blank");
+        final LoggerContextAdmin admin = new LoggerContextAdmin(ctx, Runnable::run);
+        assertThrows(IllegalArgumentException.class, () -> admin.setConfigLocationUri(""));
+        assertThrows(IllegalArgumentException.class, () -> admin.setConfigLocationUri(null));
+    }
+
+    private static void writeConfig(final Path config, final String appenderName) throws Exception {
+        final String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+                + "<Configuration status=\"OFF\">\n"
+                + "  <Appenders><Console name=\"" + appenderName + "\" target=\"SYSTEM_OUT\"/></Appenders>\n"
+                + "  <Loggers><Root level=\"error\"><AppenderRef ref=\"" + appenderName + "\"/></Root></Loggers>\n"
+                + "</Configuration>\n";
+        Files.write(config, xml.getBytes(StandardCharsets.UTF_8));
+    }
+}

log4j-core/src/main/java/org/apache/logging/log4j/core/jmx/LoggerContextAdmin.java

@@ -19,6 +19,7 @@
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -45,6 +46,7 @@
 import org.apache.logging.log4j.core.config.ConfigurationSource;
 import org.apache.logging.log4j.core.internal.annotation.SuppressFBWarnings;
 import org.apache.logging.log4j.core.util.Closer;
+import org.apache.logging.log4j.core.util.Source;
 import org.apache.logging.log4j.status.StatusLogger;
 import org.apache.logging.log4j.util.Strings;
 
@@ -128,14 +130,26 @@ public void setConfigLocationUri(final String configLocation) throws URISyntaxEx
         LOGGER.debug("---------");
         LOGGER.debug("Remote request to reconfigure using location " + configLocation);
         final File configFile = new File(configLocation);
-        ConfigurationSource configSource = null;
+        final ConfigurationSource configSource;
+        // Read the configuration into memory and close the underlying stream before handing
+        // off to ConfigurationFactory. ConfigurationSource(InputStream, File/URL) leaves stream
+        // ownership with the caller; without buffering, failures during getConfiguration/start
+        // can leave FileInputStream/URLConnection streams open.
         if (configFile.exists()) {
             LOGGER.debug("Opening config file {}", configFile.getAbsolutePath());
-            configSource = new ConfigurationSource(new FileInputStream(configFile), configFile);
+            final byte[] data;
+            try (final InputStream in = new FileInputStream(configFile)) {
+                data = toByteArray(in);
+            }
+            configSource = new ConfigurationSource(new Source(configFile), data, configFile.lastModified());
         } else {
             final URL configURL = new URL(configLocation);
             LOGGER.debug("Opening config URL {}", configURL);
-            configSource = new ConfigurationSource(configURL.openStream(), configURL);
+            final byte[] data;
+            try (final InputStream in = configURL.openStream()) {
+                data = toByteArray(in);
+            }
+            configSource = new ConfigurationSource(new Source(configURL), data, 0L);
         }
         final Configuration config = ConfigurationFactory.getInstance().getConfiguration(loggerContext, configSource);
         loggerContext.start(config);
@@ -253,4 +267,14 @@ private long nextSeqNo() {
     private long now() {
         return System.currentTimeMillis();
     }
+
+    private static byte[] toByteArray(final InputStream inputStream) throws IOException {
+        final ByteArrayOutputStream contents = new ByteArrayOutputStream(Math.max(4096, inputStream.available()));
+        final byte[] buff = new byte[4096];
+        int length;
+        while ((length = inputStream.read(buff)) >= 0) {
+            contents.write(buff, 0, length);
+        }
+        return contents.toByteArray();
+    }
 }

src/changelog/.2.x.x/fix_logger_context_admin_config_stream_leak.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<entry xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns="https://logging.apache.org/xml/ns"
+       xsi:schemaLocation="https://logging.apache.org/xml/ns https://logging.apache.org/xml/ns/log4j-changelog-0.xsd"
+       type="fixed">
+  <issue id="4218" link="https://github.com/apache/logging-log4j2/pull/4218"/>
+  <description format="asciidoc">Close configuration streams in JMX `LoggerContextAdmin.setConfigLocationUri` after buffering into `ConfigurationSource`</description>
+</entry>