Fix using stat on Linux.

byte-buddy-agent/src/main/java/net/bytebuddy/agent/VirtualMachine.java

@@ -685,7 +685,7 @@ public void close() throws IOException {
  }
 
  /**
- * Implements a connection for a Posix socket in JNA.
+ * Implements a connection for a POSIX socket in JNA.
  */
  class ForJnaPosixSocket extends OnPersistentByteChannel<Integer> {
 
@@ -700,7 +700,7 @@ class ForJnaPosixSocket extends OnPersistentByteChannel<Integer> {
  private final File socket;
 
  /**
- * Creates a connection for a virtual posix socket implemented in JNA.
+ * Creates a connection for a virtual POSIX socket implemented in JNA.
  *
  * @param library The JNA library to use.
  * @param socket The POSIX socket.
@@ -752,7 +752,7 @@ public void close() {
  }
 
  /**
- * A JNA library binding for Posix sockets.
+ * A JNA library binding for POSIX sockets.
  */
  protected interface PosixLibrary extends Library {
 
@@ -2081,26 +2081,22 @@ class ForJnaPosixEnvironment implements Dispatcher {
  private final PosixLibrary library;
 
  /**
- * The posix owner to use.
+ * The POSIX owner provider to use.
  */
- private final PosixOwner posixOwner;
+ private final PosixOwnerProvider provider;
 
  /**
- * Creates a new connector for a POSIX enviornment using JNA.
+ * Creates a new connector for a POSIX environment using JNA.
  *
  * @param attempts The maximum amount of attempts for checking the result of a foreign process.
  * @param pause The pause between two checks for another process to return.
  * @param timeUnit The time unit of the pause time.
  */
  @SuppressWarnings("deprecation")
  public ForJnaPosixEnvironment(int attempts, long pause, TimeUnit timeUnit) {
- if (Platform.isMac()) {
- posixOwner = new PosixOwner.ForMacEnvironment(attempts, pause, timeUnit);
- } else if (Platform.isAIX()) {
- posixOwner = new PosixOwner.ForAixEnvironment(attempts, pause, timeUnit);
- } else {
- posixOwner = new PosixOwner.ForLinuxEnvironment(attempts, pause, timeUnit);
- }
+ provider = Platform.isAIX() 
+ ? new PosixOwnerProvider.UsingIStat(attempts, pause, timeUnit)
+ : new PosixOwnerProvider.UsingStat(attempts, pause, timeUnit);
  library = Native.loadLibrary("c", PosixLibrary.class);
  }
 
@@ -2144,7 +2140,7 @@ public boolean isExistingProcess(int processId) {
  */
  @SuppressFBWarnings(value = "OS_OPEN_STREAM", justification = "The stream life-cycle is bound to its process.")
  public int getOwnerIdOf(File file) {
- return posixOwner.getOwnerIdOf(file);
+ return provider.getOwnerIdOf(file);
  }
 
  /**
@@ -2347,9 +2343,9 @@ protected List<String> getFieldOrder() {
  }
 
  /**
- * Represents a system that supports posix.
+ * Represents a system that supports POSIX ownership.
  */
- protected interface PosixOwner {
+ protected interface PosixOwnerProvider {
 
  /**
  * Returns the user id of the owner of the supplied file.
@@ -2360,9 +2356,9 @@ protected interface PosixOwner {
  int getOwnerIdOf(File file);
 
  /**
- * An implementation of a posix owner for Linux.
+ * An implementation of reading POSIX ownership using {@code stat}.
  */
- class ForLinuxEnvironment implements PosixOwner {
+ class UsingStat implements PosixOwnerProvider {
 
  /**
  * The maximum amount of attempts for checking the result of a foreign process.
@@ -2380,13 +2376,13 @@ class ForLinuxEnvironment implements PosixOwner {
  private final TimeUnit timeUnit;
 
  /**
- * Creates a new connector for a Linux POSIX enviornment using stat.
+ * Creates a new provider where an owner is derived using the {@code stat} command.
  *
  * @param attempts The maximum amount of attempts for checking the result of a foreign process.
  * @param pause The pause between two checks for another process to return.
  * @param timeUnit The time unit of the pause time.
  */
- public ForLinuxEnvironment(int attempts, long pause, TimeUnit timeUnit) {
+ public UsingStat(int attempts, long pause, TimeUnit timeUnit) {
  this.attempts = attempts;
  this.pause = pause;
  this.timeUnit = timeUnit;
@@ -2400,7 +2396,7 @@ public int getOwnerIdOf(File file) {
  // The binding for 'stat' is very platform dependant. To avoid the complexity of binding the correct method,
  // stat is called as a separate command. This is less efficient but more portable.
  Process process = Runtime.getRuntime().exec(new String[]{"stat",
- "-f",
+ Platform.isMac() ? "-f" : "-c",
  "%u",
  file.getAbsolutePath()});
  int attempts = this.attempts;
@@ -2438,9 +2434,9 @@ public int getOwnerIdOf(File file) {
  }
 
  /**
- * An implementation for a posix owner that represents AIX.
+ * An implementation for reading a POSIX owner using {@code istat}.
  */
- class ForAixEnvironment implements PosixOwner {
+ class UsingIStat implements PosixOwnerProvider {
 
  /**
  * A pattern to represent the owner on the console output.
@@ -2463,13 +2459,13 @@ class ForAixEnvironment implements PosixOwner {
  private final TimeUnit timeUnit;
 
  /**
- * Creates a new connector for an AIX POSIX enviornment using stat.
+ * Creates a new provider for reading a POSIX owner using {@code istat}.
  *
  * @param attempts The maximum amount of attempts for checking the result of a foreign process.
  * @param pause The pause between two checks for another process to return.
  * @param timeUnit The time unit of the pause time.
  */
- public ForAixEnvironment(int attempts, long pause, TimeUnit timeUnit) {
+ public UsingIStat(int attempts, long pause, TimeUnit timeUnit) {
  this.attempts = attempts;
  this.pause = pause;
  this.timeUnit = timeUnit;
@@ -2524,84 +2520,6 @@ public int getOwnerIdOf(File file) {
  }
  }
  }
-
- /**
- * An implementation for a posix owner that represents MacOS.
- */
- class ForMacEnvironment implements PosixOwner {
-
- /**
- * The maximum amount of attempts for checking the result of a foreign process.
- */
- private final int attempts;
-
- /**
- * The pause between two checks for another process to return.
- */
- private final long pause;
-
- /**
- * The time unit of the pause time.
- */
- private final TimeUnit timeUnit;
-
- /**
- * Creates a new connector for a Mac POSIX enviornment using stat.
- *
- * @param attempts The maximum amount of attempts for checking the result of a foreign process.
- * @param pause The pause between two checks for another process to return.
- * @param timeUnit The time unit of the pause time.
- */
- public ForMacEnvironment(int attempts, long pause, TimeUnit timeUnit) {
- this.attempts = attempts;
- this.pause = pause;
- this.timeUnit = timeUnit;
- }
-
- /**
- * {@inheritDoc}
- */
- public int getOwnerIdOf(File file) {
- try {
- // The binding for 'stat' is very platform dependant. To avoid the complexity of binding the correct method,
- // stat is called as a separate command. This is less efficient but more portable.
- Process process = Runtime.getRuntime().exec(new String[]{"stat",
- "-f",
- "%u",
- file.getAbsolutePath()});
- int attempts = this.attempts;
- String line = null;
- do {
- try {
- if (process.exitValue() != 0) {
- throw new IllegalStateException("Error while executing stat");
- }
- BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream(), "UTF-8"));
- try {
- line = reader.readLine();
- } finally {
- reader.close();
- }
- break;
- } catch (IllegalThreadStateException ignored) {
- try {
- Thread.sleep(timeUnit.toMillis(pause));
- } catch (InterruptedException exception) {
- Thread.currentThread().interrupt();
- throw new IllegalStateException(exception);
- }
- }
- } while (--attempts > 0);
- if (line == null) {
- process.destroy();
- throw new IllegalStateException("Command for stat did not exit in time");
- }
- return Integer.parseInt(line);
- } catch (IOException exception) {
- throw new IllegalStateException("Unable to execute stat command", exception);
- }
- }
- }
  }
  }