• 解决Exception: org.apache.hadoop.io.nativeio.NativeIO$Windows.access0(Ljava/lang/String;I)Z


    在项目中添加src中添加NativeIO类

    /**
     * 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.hadoop.io.nativeio;
    
    import java.io.File;
    import java.io.FileDescriptor;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.RandomAccessFile;
    import java.lang.reflect.Field;
    import java.nio.ByteBuffer;
    import java.nio.MappedByteBuffer;
    import java.util.Map;
    import java.util.concurrent.ConcurrentHashMap;
    
    import org.apache.hadoop.classification.InterfaceAudience;
    import org.apache.hadoop.classification.InterfaceStability;
    import org.apache.hadoop.conf.Configuration;
    import org.apache.hadoop.fs.CommonConfigurationKeys;
    import org.apache.hadoop.io.SecureIOUtils.AlreadyExistsException;
    import org.apache.hadoop.util.NativeCodeLoader;
    import org.apache.hadoop.util.Shell;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    
    import sun.misc.Unsafe;
    
    import com.google.common.annotations.VisibleForTesting;
    
    /**
     * JNI wrappers for various native IO-related calls not available in Java.
     * These functions should generally be used alongside a fallback to another
     * more portable mechanism.
     */
    @InterfaceAudience.Private
    @InterfaceStability.Unstable
    public class NativeIO {
      public static class POSIX {
        // Flags for open() call from bits/fcntl.h
        public static final int O_RDONLY   =    00;
        public static final int O_WRONLY   =    01;
        public static final int O_RDWR     =    02;
        public static final int O_CREAT    =  0100;
        public static final int O_EXCL     =  0200;
        public static final int O_NOCTTY   =  0400;
        public static final int O_TRUNC    = 01000;
        public static final int O_APPEND   = 02000;
        public static final int O_NONBLOCK = 04000;
        public static final int O_SYNC   =  010000;
        public static final int O_ASYNC  =  020000;
        public static final int O_FSYNC = O_SYNC;
        public static final int O_NDELAY = O_NONBLOCK;
    
        // Flags for posix_fadvise() from bits/fcntl.h
        /* No further special treatment.  */
        public static final int POSIX_FADV_NORMAL = 0;
        /* Expect random page references.  */
        public static final int POSIX_FADV_RANDOM = 1;
        /* Expect sequential page references.  */
        public static final int POSIX_FADV_SEQUENTIAL = 2;
        /* Will need these pages.  */
        public static final int POSIX_FADV_WILLNEED = 3;
        /* Don't need these pages.  */
        public static final int POSIX_FADV_DONTNEED = 4;
        /* Data will be accessed once.  */
        public static final int POSIX_FADV_NOREUSE = 5;
    
    
        /* Wait upon writeout of all pages
           in the range before performing the
           write.  */
        public static final int SYNC_FILE_RANGE_WAIT_BEFORE = 1;
        /* Initiate writeout of all those
           dirty pages in the range which are
           not presently under writeback.  */
        public static final int SYNC_FILE_RANGE_WRITE = 2;
    
        /* Wait upon writeout of all pages in
           the range after performing the
           write.  */
        public static final int SYNC_FILE_RANGE_WAIT_AFTER = 4;
    
        private static final Log LOG = LogFactory.getLog(NativeIO.class);
    
        private static boolean nativeLoaded = false;
        private static boolean fadvisePossible = true;
        private static boolean syncFileRangePossible = true;
    
        static final String WORKAROUND_NON_THREADSAFE_CALLS_KEY =
          "hadoop.workaround.non.threadsafe.getpwuid";
        static final boolean WORKAROUND_NON_THREADSAFE_CALLS_DEFAULT = true;
    
        private static long cacheTimeout = -1;
    
        private static CacheManipulator cacheManipulator = new CacheManipulator();
    
        public static CacheManipulator getCacheManipulator() {
          return cacheManipulator;
        }
    
        public static void setCacheManipulator(CacheManipulator cacheManipulator) {
          POSIX.cacheManipulator = cacheManipulator;
        }
    
        /**
         * Used to manipulate the operating system cache.
         */
        @VisibleForTesting
        public static class CacheManipulator {
          public void mlock(String identifier, ByteBuffer buffer,
              long len) throws IOException {
            POSIX.mlock(buffer, len);
          }
    
          public long getMemlockLimit() {
            return NativeIO.getMemlockLimit();
          }
    
          public long getOperatingSystemPageSize() {
            return NativeIO.getOperatingSystemPageSize();
          }
    
          public void posixFadviseIfPossible(String identifier,
            FileDescriptor fd, long offset, long len, int flags)
                throws NativeIOException {
            POSIX.posixFadviseIfPossible(identifier, fd, offset,
                len, flags);
          }
    
          public boolean verifyCanMlock() {
            return NativeIO.isAvailable();
          }
        }
    
        /**
         * A CacheManipulator used for testing which does not actually call mlock.
         * This allows many tests to be run even when the operating system does not
         * allow mlock, or only allows limited mlocking.
         */
        @VisibleForTesting
        public static class NoMlockCacheManipulator extends CacheManipulator {
          public void mlock(String identifier, ByteBuffer buffer,
              long len) throws IOException {
            LOG.info("mlocking " + identifier);
          }
    
          public long getMemlockLimit() {
            return 1125899906842624L;
          }
    
          public long getOperatingSystemPageSize() {
            return 4096;
          }
    
          public boolean verifyCanMlock() {
            return true;
          }
        }
    
        static {
          if (NativeCodeLoader.isNativeCodeLoaded()) {
            try {
              Configuration conf = new Configuration();
              workaroundNonThreadSafePasswdCalls = conf.getBoolean(
                WORKAROUND_NON_THREADSAFE_CALLS_KEY,
                WORKAROUND_NON_THREADSAFE_CALLS_DEFAULT);
    
              initNative();
              nativeLoaded = true;
    
              cacheTimeout = conf.getLong(
                CommonConfigurationKeys.HADOOP_SECURITY_UID_NAME_CACHE_TIMEOUT_KEY,
                CommonConfigurationKeys.HADOOP_SECURITY_UID_NAME_CACHE_TIMEOUT_DEFAULT) *
                1000;
              LOG.debug("Initialized cache for IDs to User/Group mapping with a " +
                " cache timeout of " + cacheTimeout/1000 + " seconds.");
    
            } catch (Throwable t) {
              // This can happen if the user has an older version of libhadoop.so
              // installed - in this case we can continue without native IO
              // after warning
              LOG.error("Unable to initialize NativeIO libraries", t);
            }
          }
        }
    
        /**
         * Return true if the JNI-based native IO extensions are available.
         */
        public static boolean isAvailable() {
          return NativeCodeLoader.isNativeCodeLoaded() && nativeLoaded;
        }
    
        private static void assertCodeLoaded() throws IOException {
          if (!isAvailable()) {
            throw new IOException("NativeIO was not loaded");
          }
        }
    
        /** Wrapper around open(2) */
        public static native FileDescriptor open(String path, int flags, int mode) throws IOException;
        /** Wrapper around fstat(2) */
        private static native Stat fstat(FileDescriptor fd) throws IOException;
    
        /** Native chmod implementation. On UNIX, it is a wrapper around chmod(2) */
        private static native void chmodImpl(String path, int mode) throws IOException;
    
        public static void chmod(String path, int mode) throws IOException {
          if (!Shell.WINDOWS) {
            chmodImpl(path, mode);
          } else {
            try {
              chmodImpl(path, mode);
            } catch (NativeIOException nioe) {
              if (nioe.getErrorCode() == 3) {
                throw new NativeIOException("No such file or directory",
                    Errno.ENOENT);
              } else {
                LOG.warn(String.format("NativeIO.chmod error (%d): %s",
                    nioe.getErrorCode(), nioe.getMessage()));
                throw new NativeIOException("Unknown error", Errno.UNKNOWN);
              }
            }
          }
        }
    
        /** Wrapper around posix_fadvise(2) */
        static native void posix_fadvise(
          FileDescriptor fd, long offset, long len, int flags) throws NativeIOException;
    
        /** Wrapper around sync_file_range(2) */
        static native void sync_file_range(
          FileDescriptor fd, long offset, long nbytes, int flags) throws NativeIOException;
    
        /**
         * Call posix_fadvise on the given file descriptor. See the manpage
         * for this syscall for more information. On systems where this
         * call is not available, does nothing.
         *
         * @throws NativeIOException if there is an error with the syscall
         */
        static void posixFadviseIfPossible(String identifier,
            FileDescriptor fd, long offset, long len, int flags)
            throws NativeIOException {
          if (nativeLoaded && fadvisePossible) {
            try {
              posix_fadvise(fd, offset, len, flags);
            } catch (UnsupportedOperationException uoe) {
              fadvisePossible = false;
            } catch (UnsatisfiedLinkError ule) {
              fadvisePossible = false;
            }
          }
        }
    
        /**
         * Call sync_file_range on the given file descriptor. See the manpage
         * for this syscall for more information. On systems where this
         * call is not available, does nothing.
         *
         * @throws NativeIOException if there is an error with the syscall
         */
        public static void syncFileRangeIfPossible(
            FileDescriptor fd, long offset, long nbytes, int flags)
            throws NativeIOException {
          if (nativeLoaded && syncFileRangePossible) {
            try {
              sync_file_range(fd, offset, nbytes, flags);
            } catch (UnsupportedOperationException uoe) {
              syncFileRangePossible = false;
            } catch (UnsatisfiedLinkError ule) {
              syncFileRangePossible = false;
            }
          }
        }
    
        static native void mlock_native(
            ByteBuffer buffer, long len) throws NativeIOException;
        static native void munlock_native(
            ByteBuffer buffer, long len) throws NativeIOException;
    
        /**
         * Locks the provided direct ByteBuffer into memory, preventing it from
         * swapping out. After a buffer is locked, future accesses will not incur
         * a page fault.
         * 
         * See the mlock(2) man page for more information.
         * 
         * @throws NativeIOException
         */
        static void mlock(ByteBuffer buffer, long len)
            throws IOException {
          assertCodeLoaded();
          if (!buffer.isDirect()) {
            throw new IOException("Cannot mlock a non-direct ByteBuffer");
          }
          mlock_native(buffer, len);
        }
    
        /**
         * Unlocks a locked direct ByteBuffer, allowing it to swap out of memory.
         * This is a no-op if the ByteBuffer was not previously locked.
         * 
         * See the munlock(2) man page for more information.
         * 
         * @throws NativeIOException
         */
        public static void munlock(ByteBuffer buffer, long len)
            throws IOException {
          assertCodeLoaded();
          if (!buffer.isDirect()) {
            throw new IOException("Cannot munlock a non-direct ByteBuffer");
          }
          munlock_native(buffer, len);
        }
        
        /**
         * Unmaps the block from memory. See munmap(2).
         *
         * There isn't any portable way to unmap a memory region in Java.
         * So we use the sun.nio method here.
         * Note that unmapping a memory region could cause crashes if code
         * continues to reference the unmapped code.  However, if we don't
         * manually unmap the memory, we are dependent on the finalizer to
         * do it, and we have no idea when the finalizer will run.
         *
         * @param buffer    The buffer to unmap.
         */
        public static void munmap(MappedByteBuffer buffer) {
          if (buffer instanceof sun.nio.ch.DirectBuffer) {
            sun.misc.Cleaner cleaner =
                ((sun.nio.ch.DirectBuffer)buffer).cleaner();
            cleaner.clean();
          }
        }
    
        /** Linux only methods used for getOwner() implementation */
        private static native long getUIDforFDOwnerforOwner(FileDescriptor fd) throws IOException;
        private static native String getUserName(long uid) throws IOException;
    
        /**
         * Result type of the fstat call
         */
        public static class Stat {
          private int ownerId, groupId;
          private String owner, group;
          private int mode;
    
          // Mode constants
          public static final int S_IFMT = 0170000;      /* type of file */
          public static final int   S_IFIFO  = 0010000;  /* named pipe (fifo) */
          public static final int   S_IFCHR  = 0020000;  /* character special */
          public static final int   S_IFDIR  = 0040000;  /* directory */
          public static final int   S_IFBLK  = 0060000;  /* block special */
          public static final int   S_IFREG  = 0100000;  /* regular */
          public static final int   S_IFLNK  = 0120000;  /* symbolic link */
          public static final int   S_IFSOCK = 0140000;  /* socket */
          public static final int   S_IFWHT  = 0160000;  /* whiteout */
          public static final int S_ISUID = 0004000;  /* set user id on execution */
          public static final int S_ISGID = 0002000;  /* set group id on execution */
          public static final int S_ISVTX = 0001000;  /* save swapped text even after use */
          public static final int S_IRUSR = 0000400;  /* read permission, owner */
          public static final int S_IWUSR = 0000200;  /* write permission, owner */
          public static final int S_IXUSR = 0000100;  /* execute/search permission, owner */
    
          Stat(int ownerId, int groupId, int mode) {
            this.ownerId = ownerId;
            this.groupId = groupId;
            this.mode = mode;
          }
          
          Stat(String owner, String group, int mode) {
            if (!Shell.WINDOWS) {
              this.owner = owner;
            } else {
              this.owner = stripDomain(owner);
            }
            if (!Shell.WINDOWS) {
              this.group = group;
            } else {
              this.group = stripDomain(group);
            }
            this.mode = mode;
          }
          
          @Override
          public String toString() {
            return "Stat(owner='" + owner + "', group='" + group + "'" +
              ", mode=" + mode + ")";
          }
    
          public String getOwner() {
            return owner;
          }
          public String getGroup() {
            return group;
          }
          public int getMode() {
            return mode;
          }
        }
    
        /**
         * Returns the file stat for a file descriptor.
         *
         * @param fd file descriptor.
         * @return the file descriptor file stat.
         * @throws IOException thrown if there was an IO error while obtaining the file stat.
         */
        public static Stat getFstat(FileDescriptor fd) throws IOException {
          Stat stat = null;
          if (!Shell.WINDOWS) {
            stat = fstat(fd); 
            stat.owner = getName(IdCache.USER, stat.ownerId);
            stat.group = getName(IdCache.GROUP, stat.groupId);
          } else {
            try {
              stat = fstat(fd);
            } catch (NativeIOException nioe) {
              if (nioe.getErrorCode() == 6) {
                throw new NativeIOException("The handle is invalid.",
                    Errno.EBADF);
              } else {
                LOG.warn(String.format("NativeIO.getFstat error (%d): %s",
                    nioe.getErrorCode(), nioe.getMessage()));
                throw new NativeIOException("Unknown error", Errno.UNKNOWN);
              }
            }
          }
          return stat;
        }
    
        private static String getName(IdCache domain, int id) throws IOException {
          Map<Integer, CachedName> idNameCache = (domain == IdCache.USER)
            ? USER_ID_NAME_CACHE : GROUP_ID_NAME_CACHE;
          String name;
          CachedName cachedName = idNameCache.get(id);
          long now = System.currentTimeMillis();
          if (cachedName != null && (cachedName.timestamp + cacheTimeout) > now) {
            name = cachedName.name;
          } else {
            name = (domain == IdCache.USER) ? getUserName(id) : getGroupName(id);
            if (LOG.isDebugEnabled()) {
              String type = (domain == IdCache.USER) ? "UserName" : "GroupName";
              LOG.debug("Got " + type + " " + name + " for ID " + id +
                " from the native implementation");
            }
            cachedName = new CachedName(name, now);
            idNameCache.put(id, cachedName);
          }
          return name;
        }
    
        static native String getUserName(int uid) throws IOException;
        static native String getGroupName(int uid) throws IOException;
    
        private static class CachedName {
          final long timestamp;
          final String name;
    
          public CachedName(String name, long timestamp) {
            this.name = name;
            this.timestamp = timestamp;
          }
        }
    
        private static final Map<Integer, CachedName> USER_ID_NAME_CACHE =
          new ConcurrentHashMap<Integer, CachedName>();
    
        private static final Map<Integer, CachedName> GROUP_ID_NAME_CACHE =
          new ConcurrentHashMap<Integer, CachedName>();
    
        private enum IdCache { USER, GROUP }
    
        public final static int MMAP_PROT_READ = 0x1; 
        public final static int MMAP_PROT_WRITE = 0x2; 
        public final static int MMAP_PROT_EXEC = 0x4; 
    
        public static native long mmap(FileDescriptor fd, int prot,
            boolean shared, long length) throws IOException;
    
        public static native void munmap(long addr, long length)
            throws IOException;
      }
    
      private static boolean workaroundNonThreadSafePasswdCalls = false;
    
    
      public static class Windows {
        // Flags for CreateFile() call on Windows
        public static final long GENERIC_READ = 0x80000000L;
        public static final long GENERIC_WRITE = 0x40000000L;
    
        public static final long FILE_SHARE_READ = 0x00000001L;
        public static final long FILE_SHARE_WRITE = 0x00000002L;
        public static final long FILE_SHARE_DELETE = 0x00000004L;
    
        public static final long CREATE_NEW = 1;
        public static final long CREATE_ALWAYS = 2;
        public static final long OPEN_EXISTING = 3;
        public static final long OPEN_ALWAYS = 4;
        public static final long TRUNCATE_EXISTING = 5;
    
        public static final long FILE_BEGIN = 0;
        public static final long FILE_CURRENT = 1;
        public static final long FILE_END = 2;
    
        /** Wrapper around CreateFile() on Windows */
        public static native FileDescriptor createFile(String path,
            long desiredAccess, long shareMode, long creationDisposition)
            throws IOException;
    
        /** Wrapper around SetFilePointer() on Windows */
        public static native long setFilePointer(FileDescriptor fd,
            long distanceToMove, long moveMethod) throws IOException;
    
        /** Windows only methods used for getOwner() implementation */
        private static native String getOwner(FileDescriptor fd) throws IOException;
    
        /** Supported list of Windows access right flags */
        public static enum AccessRight {
          ACCESS_READ (0x0001),      // FILE_READ_DATA
          ACCESS_WRITE (0x0002),     // FILE_WRITE_DATA
          ACCESS_EXECUTE (0x0020);   // FILE_EXECUTE
    
          private final int accessRight;
          AccessRight(int access) {
            accessRight = access;
          }
    
          public int accessRight() {
            return accessRight;
          }
        };
    
        /** Windows only method used to check if the current process has requested
         *  access rights on the given path. */
        private static native boolean access0(String path, int requestedAccess);
    
        /**
         * Checks whether the current process has desired access rights on
         * the given path.
         * 
         * Longer term this native function can be substituted with JDK7
         * function Files#isReadable, isWritable, isExecutable.
         *
         * @param path input path
         * @param desiredAccess ACCESS_READ, ACCESS_WRITE or ACCESS_EXECUTE
         * @return true if access is allowed
         * @throws IOException I/O exception on error
         */
        public static boolean access(String path, AccessRight desiredAccess)
            throws IOException {
            return true;
            //return access0(path, desiredAccess.accessRight());
        }
    
        static {
          if (NativeCodeLoader.isNativeCodeLoaded()) {
            try {
              initNative();
              nativeLoaded = true;
            } catch (Throwable t) {
              // This can happen if the user has an older version of libhadoop.so
              // installed - in this case we can continue without native IO
              // after warning
              LOG.error("Unable to initialize NativeIO libraries", t);
            }
          }
        }
      }
    
      private static final Log LOG = LogFactory.getLog(NativeIO.class);
    
      private static boolean nativeLoaded = false;
    
      static {
        if (NativeCodeLoader.isNativeCodeLoaded()) {
          try {
            initNative();
            nativeLoaded = true;
          } catch (Throwable t) {
            // This can happen if the user has an older version of libhadoop.so
            // installed - in this case we can continue without native IO
            // after warning
            LOG.error("Unable to initialize NativeIO libraries", t);
          }
        }
      }
    
      /**
       * Return true if the JNI-based native IO extensions are available.
       */
      public static boolean isAvailable() {
        return NativeCodeLoader.isNativeCodeLoaded() && nativeLoaded;
      }
    
      /** Initialize the JNI method ID and class ID cache */
      private static native void initNative();
    
      /**
       * Get the maximum number of bytes that can be locked into memory at any
       * given point.
       *
       * @return 0 if no bytes can be locked into memory;
       *         Long.MAX_VALUE if there is no limit;
       *         The number of bytes that can be locked into memory otherwise.
       */
      static long getMemlockLimit() {
        return isAvailable() ? getMemlockLimit0() : 0;
      }
    
      private static native long getMemlockLimit0();
      
      /**
       * @return the operating system's page size.
       */
      static long getOperatingSystemPageSize() {
        try {
          Field f = Unsafe.class.getDeclaredField("theUnsafe");
          f.setAccessible(true);
          Unsafe unsafe = (Unsafe)f.get(null);
          return unsafe.pageSize();
        } catch (Throwable e) {
          LOG.warn("Unable to get operating system page size.  Guessing 4096.", e);
          return 4096;
        }
      }
    
      private static class CachedUid {
        final long timestamp;
        final String username;
        public CachedUid(String username, long timestamp) {
          this.timestamp = timestamp;
          this.username = username;
        }
      }
      private static final Map<Long, CachedUid> uidCache =
          new ConcurrentHashMap<Long, CachedUid>();
      private static long cacheTimeout;
      private static boolean initialized = false;
      
      /**
       * The Windows logon name has two part, NetBIOS domain name and
       * user account name, of the format DOMAINUserName. This method
       * will remove the domain part of the full logon name.
       *
       * @param the full principal name containing the domain
       * @return name with domain removed
       */
      private static String stripDomain(String name) {
        int i = name.indexOf('\');
        if (i != -1)
          name = name.substring(i + 1);
        return name;
      }
    
      public static String getOwner(FileDescriptor fd) throws IOException {
        ensureInitialized();
        if (Shell.WINDOWS) {
          String owner = Windows.getOwner(fd);
          owner = stripDomain(owner);
          return owner;
        } else {
          long uid = POSIX.getUIDforFDOwnerforOwner(fd);
          CachedUid cUid = uidCache.get(uid);
          long now = System.currentTimeMillis();
          if (cUid != null && (cUid.timestamp + cacheTimeout) > now) {
            return cUid.username;
          }
          String user = POSIX.getUserName(uid);
          LOG.info("Got UserName " + user + " for UID " + uid
              + " from the native implementation");
          cUid = new CachedUid(user, now);
          uidCache.put(uid, cUid);
          return user;
        }
      }
    
      /**
       * Create a FileInputStream that shares delete permission on the
       * file opened, i.e. other process can delete the file the
       * FileInputStream is reading. Only Windows implementation uses
       * the native interface.
       */
      public static FileInputStream getShareDeleteFileInputStream(File f)
          throws IOException {
        if (!Shell.WINDOWS) {
          // On Linux the default FileInputStream shares delete permission
          // on the file opened.
          //
          return new FileInputStream(f);
        } else {
          // Use Windows native interface to create a FileInputStream that
          // shares delete permission on the file opened.
          //
          FileDescriptor fd = Windows.createFile(
              f.getAbsolutePath(),
              Windows.GENERIC_READ,
              Windows.FILE_SHARE_READ |
                  Windows.FILE_SHARE_WRITE |
                  Windows.FILE_SHARE_DELETE,
              Windows.OPEN_EXISTING);
          return new FileInputStream(fd);
        }
      }
    
      /**
       * Create a FileInputStream that shares delete permission on the
       * file opened at a given offset, i.e. other process can delete
       * the file the FileInputStream is reading. Only Windows implementation
       * uses the native interface.
       */
      public static FileInputStream getShareDeleteFileInputStream(File f, long seekOffset)
          throws IOException {
        if (!Shell.WINDOWS) {
          RandomAccessFile rf = new RandomAccessFile(f, "r");
          if (seekOffset > 0) {
            rf.seek(seekOffset);
          }
          return new FileInputStream(rf.getFD());
        } else {
          // Use Windows native interface to create a FileInputStream that
          // shares delete permission on the file opened, and set it to the
          // given offset.
          //
          FileDescriptor fd = Windows.createFile(
              f.getAbsolutePath(),
              Windows.GENERIC_READ,
              Windows.FILE_SHARE_READ |
                  Windows.FILE_SHARE_WRITE |
                  Windows.FILE_SHARE_DELETE,
              Windows.OPEN_EXISTING);
          if (seekOffset > 0)
            Windows.setFilePointer(fd, seekOffset, Windows.FILE_BEGIN);
          return new FileInputStream(fd);
        }
      }
    
      /**
       * Create the specified File for write access, ensuring that it does not exist.
       * @param f the file that we want to create
       * @param permissions we want to have on the file (if security is enabled)
       *
       * @throws AlreadyExistsException if the file already exists
       * @throws IOException if any other error occurred
       */
      public static FileOutputStream getCreateForWriteFileOutputStream(File f, int permissions)
          throws IOException {
        if (!Shell.WINDOWS) {
          // Use the native wrapper around open(2)
          try {
            FileDescriptor fd = POSIX.open(f.getAbsolutePath(),
                POSIX.O_WRONLY | POSIX.O_CREAT
                    | POSIX.O_EXCL, permissions);
            return new FileOutputStream(fd);
          } catch (NativeIOException nioe) {
            if (nioe.getErrno() == Errno.EEXIST) {
              throw new AlreadyExistsException(nioe);
            }
            throw nioe;
          }
        } else {
          // Use the Windows native APIs to create equivalent FileOutputStream
          try {
            FileDescriptor fd = Windows.createFile(f.getCanonicalPath(),
                Windows.GENERIC_WRITE,
                Windows.FILE_SHARE_DELETE
                    | Windows.FILE_SHARE_READ
                    | Windows.FILE_SHARE_WRITE,
                Windows.CREATE_NEW);
            POSIX.chmod(f.getCanonicalPath(), permissions);
            return new FileOutputStream(fd);
          } catch (NativeIOException nioe) {
            if (nioe.getErrorCode() == 80) {
              // ERROR_FILE_EXISTS
              // 80 (0x50)
              // The file exists
              throw new AlreadyExistsException(nioe);
            }
            throw nioe;
          }
        }
      }
    
      private synchronized static void ensureInitialized() {
        if (!initialized) {
          cacheTimeout =
              new Configuration().getLong("hadoop.security.uid.cache.secs",
                  4*60*60) * 1000;
          LOG.info("Initialized cache for UID to User mapping with a cache" +
              " timeout of " + cacheTimeout/1000 + " seconds.");
          initialized = true;
        }
      }
      
      /**
       * A version of renameTo that throws a descriptive exception when it fails.
       *
       * @param src                  The source path
       * @param dst                  The destination path
       * 
       * @throws NativeIOException   On failure.
       */
      public static void renameTo(File src, File dst)
          throws IOException {
        if (!nativeLoaded) {
          if (!src.renameTo(dst)) {
            throw new IOException("renameTo(src=" + src + ", dst=" +
              dst + ") failed.");
          }
        } else {
          renameTo0(src.getAbsolutePath(), dst.getAbsolutePath());
        }
      }
    
      /**
       * A version of renameTo that throws a descriptive exception when it fails.
       *
       * @param src                  The source path
       * @param dst                  The destination path
       * 
       * @throws NativeIOException   On failure.
       */
      private static native void renameTo0(String src, String dst)
          throws NativeIOException;
    }
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  • 原文地址:https://www.cnblogs.com/mkdlf/p/7226597.html
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