src/java/org/apache/cassandra/utils/CLibrary.java - cassandra - Git at Google

 /*
  * 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.cassandra.utils;

 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileDescriptor;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.lang.reflect.Field;

 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import org.apache.commons.lang.StringUtils;

 import com.sun.jna.LastErrorException;
 import com.sun.jna.Native;

 public final class CLibrary
 {
     private static Logger logger = LoggerFactory.getLogger(CLibrary.class);

     private static final int MCL_CURRENT = 1;
     private static final int MCL_FUTURE = 2;

     private static final int ENOMEM = 12;

     private static final int F_GETFL   = 3;  /* get file status flags */
     private static final int F_SETFL   = 4;  /* set file status flags */
     private static final int F_NOCACHE = 48; /* Mac OS X specific flag, turns cache on/off */
     private static final int O_DIRECT  = 040000; /* fcntl.h */

     private static final int POSIX_FADV_NORMAL     = 0; /* fadvise.h */
     private static final int POSIX_FADV_RANDOM     = 1; /* fadvise.h */
     private static final int POSIX_FADV_SEQUENTIAL = 2; /* fadvise.h */
     private static final int POSIX_FADV_WILLNEED   = 3; /* fadvise.h */
     private static final int POSIX_FADV_DONTNEED   = 4; /* fadvise.h */
     private static final int POSIX_FADV_NOREUSE    = 5; /* fadvise.h */

     static
     {
         try
         {
             Native.register("c");
         }
         catch (NoClassDefFoundError e)
         {
             logger.info("JNA not found. Native methods will be disabled.");
         }
         catch (UnsatisfiedLinkError e)
         {
             logger.info("Unable to link C library. Native methods will be disabled.");
         }
         catch (NoSuchMethodError e)
         {
             logger.warn("Obsolete version of JNA present; unable to register C library. Upgrade to JNA 3.2.7 or later");
         }
     }

     private static native int mlockall(int flags) throws LastErrorException;
     private static native int munlockall() throws LastErrorException;

     private static native int link(String from, String to) throws LastErrorException;

     // fcntl - manipulate file descriptor, `man 2 fcntl`
     public static native int fcntl(int fd, int command, long flags) throws LastErrorException;

     // fadvice
     public static native int posix_fadvise(int fd, long offset, int len, int flag) throws LastErrorException;

     private static int errno(RuntimeException e)
     {
         assert e instanceof LastErrorException;
         try
         {
             return ((LastErrorException) e).getErrorCode();
         }
         catch (NoSuchMethodError x)
         {
             logger.warn("Obsolete version of JNA present; unable to read errno. Upgrade to JNA 3.2.7 or later");
             return 0;
         }
     }

     private CLibrary() {}

     public static void tryMlockall()
     {
         try
         {
             mlockall(MCL_CURRENT);
             logger.info("JNA mlockall successful");
         }
         catch (UnsatisfiedLinkError e)
         {
             // this will have already been logged by CLibrary, no need to repeat it
         }
         catch (RuntimeException e)
         {
             if (!(e instanceof LastErrorException))
                 throw e;
             if (errno(e) == ENOMEM && System.getProperty("os.name").toLowerCase().contains("linux"))
             {
                 logger.warn("Unable to lock JVM memory (ENOMEM)."
                              + " This can result in part of the JVM being swapped out, especially with mmapped I/O enabled."
                              + " Increase RLIMIT_MEMLOCK or run Cassandra as root.");
             }
             else if (!System.getProperty("os.name").toLowerCase().contains("mac"))
             {
                 // OS X allows mlockall to be called, but always returns an error
                 logger.warn("Unknown mlockall error " + errno(e));
             }
         }
     }

     /**
      * Create a hard link for a given file.
      *
      * @param sourceFile      The name of the source file.
      * @param destinationFile The name of the destination file.
      *
      * @throws java.io.IOException if an error has occurred while creating the link.
      */
     public static void createHardLink(File sourceFile, File destinationFile) throws IOException
     {
         try
         {
             link(sourceFile.getAbsolutePath(), destinationFile.getAbsolutePath());
         }
         catch (UnsatisfiedLinkError e)
         {
             createHardLinkWithExec(sourceFile, destinationFile);
         }
         catch (RuntimeException e)
         {
             logger.error("Unable to create hard link", e);
             if (!(e instanceof LastErrorException))
                 throw e;
             // there are 17 different error codes listed on the man page.  punt until/unless we find which
             // ones actually turn up in practice.
             throw new IOException(String.format("Unable to create hard link from %s to %s (errno %d)",
                                                 sourceFile, destinationFile, errno(e)));
         }
     }

     public static void createHardLinkWithExec(File sourceFile, File destinationFile) throws IOException
     {
         String osname = System.getProperty("os.name");
         ProcessBuilder pb;
         if (osname.startsWith("Windows"))
         {
             float osversion = Float.parseFloat(System.getProperty("os.version"));
             if (osversion >= 6.0f)
             {
                 pb = new ProcessBuilder("cmd", "/c", "mklink", "/H", destinationFile.getAbsolutePath(), sourceFile.getAbsolutePath());
             }
             else
             {
                 pb = new ProcessBuilder("fsutil", "hardlink", "create", destinationFile.getAbsolutePath(), sourceFile.getAbsolutePath());
             }
         }
         else
         {
             pb = new ProcessBuilder("ln", sourceFile.getAbsolutePath(), destinationFile.getAbsolutePath());
             pb.redirectErrorStream(true);
         }
         try
         {
             exec(pb);
         }
         catch (IOException ex)
         {
             logger.error("Unable to create hard link", ex);
             throw ex;
         }
     }

     private static void exec(ProcessBuilder pb) throws IOException
     {
         Process p = pb.start();
         try
         {
             int errCode = p.waitFor();
             if (errCode != 0)
             {
                 BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
                 BufferedReader err = new BufferedReader(new InputStreamReader(p.getErrorStream()));
                 StringBuffer buff = new StringBuffer();
                 String str;
                 while ((str = in.readLine()) != null)
                     buff.append(str).append(System.getProperty("line.separator"));
                 while ((str = err.readLine()) != null)
                     buff.append(str).append(System.getProperty("line.separator"));
                 throw new IOException("Exception while executing the command: "+ StringUtils.join(pb.command(), " ") +
                                       ", command error Code: " + errCode +
                                       ", command output: "+ buff.toString());
             }
         }
         catch (InterruptedException e)
         {
             throw new RuntimeException(e);
         }
     }

     public static void trySkipCache(int fd, long offset, int len)
     {
         if (fd < 0)
             return;

         try
         {
             if (System.getProperty("os.name").toLowerCase().contains("linux"))
             {
                 posix_fadvise(fd, offset, len, POSIX_FADV_DONTNEED);
             }
         }
         catch (UnsatisfiedLinkError e)
         {
             // if JNA is unavailable just skipping Direct I/O
             // instance of this class will act like normal RandomAccessFile
         }
     }

     public static int tryFcntl(int fd, int command, int flags)
     {
         // fcntl return value may or may not be useful, depending on the command
         int result = -1;

         try
         {
             result = CLibrary.fcntl(fd, command, flags);
         }
         catch (RuntimeException e)
         {
             if (!(e instanceof LastErrorException))
                 throw e;

             logger.warn(String.format("fcntl(%d, %d, %d) failed, errno (%d).",
                                       fd, command, flags, CLibrary.errno(e)));
         }

         return result;
     }

     /**
      * Get system file descriptor from FileDescriptor object.
      * @param descriptor - FileDescriptor objec to get fd from
      * @return file descriptor, -1 or error
      */
     public static int getfd(FileDescriptor descriptor)
     {
         Field field = FBUtilities.getProtectedField(descriptor.getClass(), "fd");

         if (field == null)
             return -1;

         try
         {
             return field.getInt(descriptor);
         }
         catch (Exception e)
         {
             logger.warn("unable to read fd field from FileDescriptor");
         }

         return -1;
     }
 }
	/*
	* 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.cassandra.utils;

	import java.io.BufferedReader;
	import java.io.File;
	import java.io.FileDescriptor;
	import java.io.IOException;
	import java.io.InputStreamReader;
	import java.lang.reflect.Field;

	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import org.apache.commons.lang.StringUtils;

	import com.sun.jna.LastErrorException;
	import com.sun.jna.Native;

	public final class CLibrary
	{
	private static Logger logger = LoggerFactory.getLogger(CLibrary.class);

	private static final int MCL_CURRENT = 1;
	private static final int MCL_FUTURE = 2;

	private static final int ENOMEM = 12;

	private static final int F_GETFL = 3; /* get file status flags */
	private static final int F_SETFL = 4; /* set file status flags */
	private static final int F_NOCACHE = 48; /* Mac OS X specific flag, turns cache on/off */
	private static final int O_DIRECT = 040000; /* fcntl.h */

	private static final int POSIX_FADV_NORMAL = 0; /* fadvise.h */
	private static final int POSIX_FADV_RANDOM = 1; /* fadvise.h */
	private static final int POSIX_FADV_SEQUENTIAL = 2; /* fadvise.h */
	private static final int POSIX_FADV_WILLNEED = 3; /* fadvise.h */
	private static final int POSIX_FADV_DONTNEED = 4; /* fadvise.h */
	private static final int POSIX_FADV_NOREUSE = 5; /* fadvise.h */

	static
	{
	try
	{
	Native.register("c");
	}
	catch (NoClassDefFoundError e)
	{
	logger.info("JNA not found. Native methods will be disabled.");
	}
	catch (UnsatisfiedLinkError e)
	{
	logger.info("Unable to link C library. Native methods will be disabled.");
	}
	catch (NoSuchMethodError e)
	{
	logger.warn("Obsolete version of JNA present; unable to register C library. Upgrade to JNA 3.2.7 or later");
	}
	}

	private static native int mlockall(int flags) throws LastErrorException;
	private static native int munlockall() throws LastErrorException;

	private static native int link(String from, String to) throws LastErrorException;

	// fcntl - manipulate file descriptor, `man 2 fcntl`
	public static native int fcntl(int fd, int command, long flags) throws LastErrorException;

	// fadvice
	public static native int posix_fadvise(int fd, long offset, int len, int flag) throws LastErrorException;

	private static int errno(RuntimeException e)
	{
	assert e instanceof LastErrorException;
	try
	{
	return ((LastErrorException) e).getErrorCode();
	}
	catch (NoSuchMethodError x)
	{
	logger.warn("Obsolete version of JNA present; unable to read errno. Upgrade to JNA 3.2.7 or later");
	return 0;
	}
	}

	private CLibrary() {}

	public static void tryMlockall()
	{
	try
	{
	mlockall(MCL_CURRENT);
	logger.info("JNA mlockall successful");
	}
	catch (UnsatisfiedLinkError e)
	{
	// this will have already been logged by CLibrary, no need to repeat it
	}
	catch (RuntimeException e)
	{
	if (!(e instanceof LastErrorException))
	throw e;
	if (errno(e) == ENOMEM && System.getProperty("os.name").toLowerCase().contains("linux"))
	{
	logger.warn("Unable to lock JVM memory (ENOMEM)."
	+ " This can result in part of the JVM being swapped out, especially with mmapped I/O enabled."
	+ " Increase RLIMIT_MEMLOCK or run Cassandra as root.");
	}
	else if (!System.getProperty("os.name").toLowerCase().contains("mac"))
	{
	// OS X allows mlockall to be called, but always returns an error
	logger.warn("Unknown mlockall error " + errno(e));
	}
	}
	}

	/**
	* Create a hard link for a given file.
	*
	* @param sourceFile The name of the source file.
	* @param destinationFile The name of the destination file.
	*
	* @throws java.io.IOException if an error has occurred while creating the link.
	*/
	public static void createHardLink(File sourceFile, File destinationFile) throws IOException
	{
	try
	{
	link(sourceFile.getAbsolutePath(), destinationFile.getAbsolutePath());
	}
	catch (UnsatisfiedLinkError e)
	{
	createHardLinkWithExec(sourceFile, destinationFile);
	}
	catch (RuntimeException e)
	{
	logger.error("Unable to create hard link", e);
	if (!(e instanceof LastErrorException))
	throw e;
	// there are 17 different error codes listed on the man page. punt until/unless we find which
	// ones actually turn up in practice.
	throw new IOException(String.format("Unable to create hard link from %s to %s (errno %d)",
	sourceFile, destinationFile, errno(e)));
	}
	}

	public static void createHardLinkWithExec(File sourceFile, File destinationFile) throws IOException
	{
	String osname = System.getProperty("os.name");
	ProcessBuilder pb;
	if (osname.startsWith("Windows"))
	{
	float osversion = Float.parseFloat(System.getProperty("os.version"));
	if (osversion >= 6.0f)
	{
	pb = new ProcessBuilder("cmd", "/c", "mklink", "/H", destinationFile.getAbsolutePath(), sourceFile.getAbsolutePath());
	}
	else
	{
	pb = new ProcessBuilder("fsutil", "hardlink", "create", destinationFile.getAbsolutePath(), sourceFile.getAbsolutePath());
	}
	}
	else
	{
	pb = new ProcessBuilder("ln", sourceFile.getAbsolutePath(), destinationFile.getAbsolutePath());
	pb.redirectErrorStream(true);
	}
	try
	{
	exec(pb);
	}
	catch (IOException ex)
	{
	logger.error("Unable to create hard link", ex);
	throw ex;
	}
	}

	private static void exec(ProcessBuilder pb) throws IOException
	{
	Process p = pb.start();
	try
	{
	int errCode = p.waitFor();
	if (errCode != 0)
	{
	BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
	BufferedReader err = new BufferedReader(new InputStreamReader(p.getErrorStream()));
	StringBuffer buff = new StringBuffer();
	String str;
	while ((str = in.readLine()) != null)
	buff.append(str).append(System.getProperty("line.separator"));
	while ((str = err.readLine()) != null)
	buff.append(str).append(System.getProperty("line.separator"));
	throw new IOException("Exception while executing the command: "+ StringUtils.join(pb.command(), " ") +
	", command error Code: " + errCode +
	", command output: "+ buff.toString());
	}
	}
	catch (InterruptedException e)
	{
	throw new RuntimeException(e);
	}
	}

	public static void trySkipCache(int fd, long offset, int len)
	{
	if (fd < 0)
	return;

	try
	{
	if (System.getProperty("os.name").toLowerCase().contains("linux"))
	{
	posix_fadvise(fd, offset, len, POSIX_FADV_DONTNEED);
	}
	}
	catch (UnsatisfiedLinkError e)
	{
	// if JNA is unavailable just skipping Direct I/O
	// instance of this class will act like normal RandomAccessFile
	}
	}

	public static int tryFcntl(int fd, int command, int flags)
	{
	// fcntl return value may or may not be useful, depending on the command
	int result = -1;

	try
	{
	result = CLibrary.fcntl(fd, command, flags);
	}
	catch (RuntimeException e)
	{
	if (!(e instanceof LastErrorException))
	throw e;

	logger.warn(String.format("fcntl(%d, %d, %d) failed, errno (%d).",
	fd, command, flags, CLibrary.errno(e)));
	}

	return result;
	}

	/**
	* Get system file descriptor from FileDescriptor object.
	* @param descriptor - FileDescriptor objec to get fd from
	* @return file descriptor, -1 or error
	*/
	public static int getfd(FileDescriptor descriptor)
	{
	Field field = FBUtilities.getProtectedField(descriptor.getClass(), "fd");

	if (field == null)
	return -1;

	try
	{
	return field.getInt(descriptor);
	}
	catch (Exception e)
	{
	logger.warn("unable to read fd field from FileDescriptor");
	}

	return -1;
	}
	}