Martin Kellogg created ZOOKEEPER-4245: -----------------------------------------
Summary: Resource leaks in org.apache.zookeeper.server.persistence.SnapStream#getInputStream and #getOutputStream Key: ZOOKEEPER-4245 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-4245 Project: ZooKeeper Issue Type: Bug Components: server Reporter: Martin Kellogg There are three (related) possible resource leaks in the `getInputStream` and `getOutputStream` methods in `SnapStream.java`. I noticed the first because of the use of the error-prone `GZIPOutputStream`, and the other two after looking at the surrounding code. Here is the offending code (copied from [here|https://github.com/apache/zookeeper/blob/master/zookeeper-server/src/main/java/org/apache/zookeeper/server/persistence/SnapStream.java#L102]): {noformat} /** * Return the CheckedInputStream based on the extension of the fileName. * * @param file the file the InputStream read from * @return the specific InputStream * @throws IOException */ public static CheckedInputStream getInputStream(File file) throws IOException { FileInputStream fis = new FileInputStream(file); InputStream is; switch (getStreamMode(file.getName())) { case GZIP: is = new GZIPInputStream(fis); break; case SNAPPY: is = new SnappyInputStream(fis); break; case CHECKED: default: is = new BufferedInputStream(fis); } return new CheckedInputStream(is, new Adler32()); } /** * Return the OutputStream based on predefined stream mode. * * @param file the file the OutputStream writes to * @param fsync sync the file immediately after write * @return the specific OutputStream * @throws IOException */ public static CheckedOutputStream getOutputStream(File file, boolean fsync) throws IOException { OutputStream fos = fsync ? new AtomicFileOutputStream(file) : new FileOutputStream(file); OutputStream os; switch (streamMode) { case GZIP: os = new GZIPOutputStream(fos); break; case SNAPPY: os = new SnappyOutputStream(fos); break; case CHECKED: default: os = new BufferedOutputStream(fos); } return new CheckedOutputStream(os, new Adler32()); } {noformat} All three possible resource leaks are caused by the constructors of the intermediate streams (i.e. `is` and `os`), some of which might throw `IOException`s: * in `getOutputStream`, the call to `new GZIPOutputStream` can throw an exception, because `GZIPOutputStream` writes out the header in the constructor. If it does throw, then `fos` is never closed. That it does so makes it hard to use correctly; someone raised this as an issue with the JDK folks [here|https://bugs.openjdk.java.net/browse/JDK-8180899], but they closed it as "won't fix" because the constructor is documented to throw (hence the need to catch the exception here). * in `getInputStream`, the call to `new GZIPInputStream` can throw an `IOException` for a similar reason, causing the file handle held by `fis` to leak. * similarly, the call to `new SnappyInputStream` can throw an `IOException`, because it tries to read the file header during construction, which also causes `fis` to leak. `SnappyOutputStream` cannot throw; I checked [here|https://github.com/xerial/snappy-java/blob/master/src/main/java/org/xerial/snappy/SnappyOutputStream.java]. I'll submit a PR with a (simple) fix shortly after this bug report goes up and gets assigned an issue number, and add a link to this issue. -- This message was sent by Atlassian Jira (v8.3.4#803005)