/**
* 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.
*/
#ifndef LIBHDFS_HDFS_H
#define LIBHDFS_HDFS_H
#include <errno.h> /* for EINTERNAL, etc. */
#include <fcntl.h> /* for O_RDONLY, O_WRONLY */
#include <stdint.h> /* for uint64_t, etc. */
#include <time.h> /* for time_t */
#ifndef O_RDONLY
#define O_RDONLY 1
#endif
#ifndef O_WRONLY
#define O_WRONLY 2
#endif
#ifndef EINTERNAL
#define EINTERNAL 255
#endif
#define ELASTIC_BYTE_BUFFER_POOL_CLASS \
"org/apache/hadoop/io/ElasticByteBufferPool"
/** All APIs set errno to meaningful values */
#ifdef __cplusplus
extern "C" {
#endif
/**
* Some utility decls used in libhdfs.
*/
struct hdfsBuilder;
typedef int32_t tSize; /// size of data for read/write io ops
typedef time_t tTime; /// time type in seconds
typedef int64_t tOffset;/// offset within the file
typedef uint16_t tPort; /// port
typedef enum tObjectKind {
kObjectKindFile = 'F',
kObjectKindDirectory = 'D',
} tObjectKind;
/**
* The C reflection of org.apache.org.hadoop.FileSystem .
*/
struct hdfs_internal;
typedef struct hdfs_internal* hdfsFS;
struct hdfsFile_internal;
typedef struct hdfsFile_internal* hdfsFile;
struct hadoopRzOptions;
struct hadoopRzBuffer;
/**
* Determine if a file is open for read.
*
* @param file The HDFS file
* @return 1 if the file is open for read; 0 otherwise
*/
int hdfsFileIsOpenForRead(hdfsFile file);
/**
* Determine if a file is open for write.
*
* @param file The HDFS file
* @return 1 if the file is open for write; 0 otherwise
*/
int hdfsFileIsOpenForWrite(hdfsFile file);
struct hdfsReadStatistics {
uint64_t totalBytesRead;
uint64_t totalLocalBytesRead;
uint64_t totalShortCircuitBytesRead;
uint64_t totalZeroCopyBytesRead;
};
/**
* Get read statistics about a file. This is only applicable to files
* opened for reading.
*
* @param file The HDFS file
* @param stats (out parameter) on a successful return, the read
* statistics. Unchanged otherwise. You must free the
* returned statistics with hdfsFileFreeReadStatistics.
* @return 0 if the statistics were successfully returned,
* -1 otherwise. On a failure, please check errno against
* ENOTSUP. webhdfs, LocalFilesystem, and so forth may
* not support read statistics.
*/
int hdfsFileGetReadStatistics(hdfsFile file,
struct hdfsReadStatistics **stats);
/**
* @param stats HDFS read statistics for a file.
*
* @return the number of remote bytes read.
*/
int64_t hdfsReadStatisticsGetRemoteBytesRead(
const struct hdfsReadStatistics *stats);
/**
* Free some HDFS read statistics.
*
* @param stats The HDFS read statistics to free.
*/
void hdfsFileFreeReadStatistics(struct hdfsReadStatistics *stats);
/**
* hdfsConnectAsUser - Connect to a hdfs file system as a specific user
* Connect to the hdfs.
* @param nn The NameNode. See hdfsBuilderSetNameNode for details.
* @param port The port on which the server is listening.
* @param user the user name (this is hadoop domain user). Or NULL is equivelant to hhdfsConnect(host, port)
* @return Returns a handle to the filesystem or NULL on error.
* @deprecated Use hdfsBuilderConnect instead.
*/
hdfsFS hdfsConnectAsUser(const char* nn, tPort port, const char *user);
/**
* hdfsConnect - Connect to a hdfs file system.
* Connect to the hdfs.
* @param nn The NameNode. See hdfsBuilderSetNameNode for details.
* @param port The port on which the server is listening.
* @return Returns a handle to the filesystem or NULL on error.
* @deprecated Use hdfsBuilderConnect instead.
*/
hdfsFS hdfsConnect(const char* nn, tPort port);
/**
* hdfsConnect - Connect to an hdfs file system.
*
* Forces a new instance to be created
*
* @param nn The NameNode. See hdfsBuilderSetNameNode for details.
* @param port The port on which the server is listening.
* @param user The user name to use when connecting
* @return Returns a handle to the filesystem or NULL on error.
* @deprecated Use hdfsBuilderConnect instead.
*/
hdfsFS hdfsConnectAsUserNewInstance(const char* nn, tPort port, const char *user );
/**
* hdfsConnect - Connect to an hdfs file system.
*
* Forces a new instance to be created
*
* @param nn The NameNode. See hdfsBuilderSetNameNode for details.
* @param port The port on which the server is listening.
* @return Returns a handle to the filesystem or NULL on error.
* @deprecated Use hdfsBuilderConnect instead.
*/
hdfsFS hdfsConnectNewInstance(const char* nn, tPort port);
/**
* Connect to HDFS using the parameters defined by the builder.
*
* The HDFS builder will be freed, whether or not the connection was
* successful.
*
* Every successful call to hdfsBuilderConnect should be matched with a call
* to hdfsDisconnect, when the hdfsFS is no longer needed.
*
* @param bld The HDFS builder
* @return Returns a handle to the filesystem, or NULL on error.
*/
hdfsFS hdfsBuilderConnect(struct hdfsBuilder *bld);
/**
* Create an HDFS builder.
*
* @return The HDFS builder, or NULL on error.
*/
struct hdfsBuilder *hdfsNewBuilder(void);
/**
* Force the builder to always create a new instance of the FileSystem,
* rather than possibly finding one in the cache.
*
* @param bld The HDFS builder
*/
void hdfsBuilderSetForceNewInstance(struct hdfsBuilder *bld);
/**
* Set the HDFS NameNode to connect to.
*
* @param bld The HDFS builder
* @param nn The NameNode to use.
*
* If the string given is 'default', the default NameNode
* configuration will be used (from the XML configuration files)
*
* If NULL is given, a LocalFileSystem will be created.
*
* If the string starts with a protocol type such as file:// or
* hdfs://, this protocol type will be used. If not, the
* hdfs:// protocol type will be used.
*
* You may specify a NameNode port in the usual way by
* passing a string of the format hdfs://<hostname>:<port>.
* Alternately, you may set the port with
* hdfsBuilderSetNameNodePort. However, you must not pass the
* port in two different ways.
*/
void hdfsBuilderSetNameNode(struct hdfsBuilder *bld, const char *nn);
/**
* Set the port of the HDFS NameNode to connect to.
*
* @param bld The HDFS builder
* @param port The port.
*/
void hdfsBuilderSetNameNodePort(struct hdfsBuilder *bld, tPort port);
/**
* Set the username to use when connecting to the HDFS cluster.
*
* @param bld The HDFS builder
* @param userName The user name. The string will be shallow-copied.
*/
void hdfsBuilderSetUserName(struct hdfsBuilder *bld, const char *userName);
/**
* Set the path to the Kerberos ticket cache to use when connecting to
* the HDFS cluster.
*
* @param bld The HDFS builder
* @param kerbTicketCachePath The Kerberos ticket cache path. The string
* will be shallow-copied.
*/
void hdfsBuilderSetKerbTicketCachePath(struct hdfsBuilder *bld,
const char *kerbTicketCachePath);
/**
* Free an HDFS builder.
*
* It is normally not necessary to call this function since
* hdfsBuilderConnect frees the builder.
*
* @param bld The HDFS builder
*/
void hdfsFreeBuilder(struct hdfsBuilder *bld);
/**
* Set a configuration string for an HdfsBuilder.
*
* @param key The key to set.
* @param val The value, or NULL to set no value.
* This will be shallow-copied. You are responsible for
* ensuring that it remains valid until the builder is
* freed.
*
* @return 0 on success; nonzero error code otherwise.
*/
int hdfsBuilderConfSetStr(struct hdfsBuilder *bld, const char *key,
const char *val);
/**
* Get a configuration string.
*
* @param key The key to find
* @param val (out param) The value. This will be set to NULL if the
* key isn't found. You must free this string with
* hdfsConfStrFree.
*
* @return 0 on success; nonzero error code otherwise.
* Failure to find the key is not an error.
*/
int hdfsConfGetStr(const char *key, char **val);
/**
* Get a configuration integer.
*
* @param key The key to find
* @param val (out param) The value. This will NOT be changed if the
* key isn't found.
*
* @return 0 on success; nonzero error code otherwise.
* Failure to find the key is not an error.
*/
int hdfsConfGetInt(const char *key, int32_t *val);
/**
* Free a configuration string found with hdfsConfGetStr.
*
* @param val A configuration string obtained from hdfsConfGetStr
*/
void hdfsConfStrFree(char *val);
/**
* hdfsDisconnect - Disconnect from the hdfs file system.
* Disconnect from hdfs.
* @param fs The configured filesystem handle.
* @return Returns 0 on success, -1 on error.
* Even if there is an error, the resources associated with the
* hdfsFS will be freed.
*/
int hdfsDisconnect(hdfsFS fs);
/**
* hdfsOpenFile - Open a hdfs file in given mode.
* @param fs The configured filesystem handle.
* @param path The full path to the file.
* @param flags - an | of bits/fcntl.h file flags - supported flags are O_RDONLY, O_WRONLY (meaning create or overwrite i.e., implies O_TRUNCAT),
* O_WRONLY|O_APPEND. Other flags are generally ignored other than (O_RDWR || (O_EXCL & O_CREAT)) which return NULL and set errno equal ENOTSUP.
* @param bufferSize Size of buffer for read/write - pass 0 if you want
* to use the default configured values.
* @param replication Block replication - pass 0 if you want to use
* the default configured values.
* @param blocksize Size of block - pass 0 if you want to use the
* default configured values.
* @return Returns the handle to the open file or NULL on error.
*/
hdfsFile hdfsOpenFile(hdfsFS fs, const char* path, int flags,
int bufferSize, short replication, tSize blocksize);
/**
* hdfsCloseFile - Close an open file.
* @param fs The configured filesystem handle.
* @param file The file handle.
* @return Returns 0 on success, -1 on error.
* On error, errno will be set appropriately.
* If the hdfs file was valid, the memory associated with it will
* be freed at the end of this call, even if there was an I/O
* error.
*/
int hdfsCloseFile(hdfsFS fs, hdfsFile file);
/**
* hdfsExists - Checks if a given path exsits on the filesystem
* @param fs The configured filesystem handle.
* @param path The path to look for
* @return Returns 0 on success, -1 on error.
*/
int hdfsExists(hdfsFS fs, const char *path);
/**
* hdfsSeek - Seek to given offset in file.
* This works only for files opened in read-only mode.
* @param fs The configured filesystem handle.
* @param file The file handle.
* @param desiredPos Offset into the file to seek into.
* @return Returns 0 on success, -1 on error.
*/
int hdfsSeek(hdfsFS fs, hdfsFile file, tOffset desiredPos);
/**
* hdfsTell - Get the current offset in the file, in bytes.
* @param fs The configured filesystem handle.
* @param file The file handle.
* @return Current offset, -1 on error.
*/
tOffset hdfsTell(hdfsFS fs, hdfsFile file);
/**
* hdfsRead - Read data from an open file.
* @param fs The configured filesystem handle.
* @param file The file handle.
* @param buffer The buffer to copy read bytes into.
* @param length The length of the buffer.
* @return On success, a positive number indicating how many bytes
* were read.
* On end-of-file, 0.
* On error, -1. Errno will be set to the error code.
* Just like the POSIX read function, hdfsRead will return -1
* and set errno to EINTR if data is temporarily unavailable,
* but we are not yet at the end of the file.
*/
tSize hdfsRead(hdfsFS fs, hdfsFile file, void* buffer, tSize length);
/**
* hdfsPread - Positional read of data from an open file.
* @param fs The configured filesystem handle.
* @param file The file handle.
* @param position Position from which to read
* @param buffer The buffer to copy read bytes into.
* @param length The length of the buffer.
* @return See hdfsRead
*/
tSize hdfsPread(hdfsFS fs, hdfsFile file, tOffset position,
void* buffer, tSize length);
/**
* hdfsWrite - Write data into an open file.
* @param fs The configured filesystem handle.
* @param file The file handle.
* @param buffer The data.
* @param length The no. of bytes to write.
* @return Returns the number of bytes written, -1 on error.
*/
tSize hdfsWrite(hdfsFS fs, hdfsFile file, const void* buffer,
tSize length);
/**
* hdfsWrite - Flush the data.
* @param fs The configured filesystem handle.
* @param file The file handle.
* @return Returns 0 on success, -1 on error.
*/
int hdfsFlush(hdfsFS fs, hdfsFile file);
/**
* hdfsHFlush - Flush out the data in client's user buffer. After the
* return of this call, new readers will see the data.
* @param fs configured filesystem handle
* @param file file handle
* @return 0 on success, -1 on error and sets errno
*/
int hdfsHFlush(hdfsFS fs, hdfsFile file);
/**
* hdfsHSync - Similar to posix fsync, Flush out the data in client's
* user buffer. all the way to the disk device (but the disk may have
* it in its cache).
* @param fs configured filesystem handle
* @param file file handle
* @return 0 on success, -1 on error and sets errno
*/
int hdfsHSync(hdfsFS fs, hdfsFile file);
/**
* hdfsAvailable - Number of bytes that can be read from this
* input stream without blocking.
* @param fs The configured filesystem handle.
* @param file The file handle.
* @return Returns available bytes; -1 on error.
*/
int hdfsAvailable(hdfsFS fs, hdfsFile file);
/**
* hdfsCopy - Copy file from one filesystem to another.
* @param srcFS The handle to source filesystem.
* @param src The path of source file.
* @param dstFS The handle to destination filesystem.
* @param dst The path of destination file.
* @return Returns 0 on success, -1 on error.
*/
int hdfsCopy(hdfsFS srcFS, const char* src, hdfsFS dstFS, const char* dst);
/**
* hdfsMove - Move file from one filesystem to another.
* @param srcFS The handle to source filesystem.
* @param src The path of source file.
* @param dstFS The handle to destination filesystem.
* @param dst The path of destination file.
* @return Returns 0 on success, -1 on error.
*/
int hdfsMove(hdfsFS srcFS, const char* src, hdfsFS dstFS, const char* dst);
/**
* hdfsDelete - Delete file.
* @param fs The configured filesystem handle.
* @param path The path of the file.
* @param recursive if path is a directory and set to
* non-zero, the directory is deleted else throws an exception. In
* case of a file the recursive argument is irrelevant.
* @return Returns 0 on success, -1 on error.
*/
int hdfsDelete(hdfsFS fs, const char* path, int recursive);
/**
* hdfsRename - Rename file.
* @param fs The configured filesystem handle.
* @param oldPath The path of the source file.
* @param newPath The path of the destination file.
* @return Returns 0 on success, -1 on error.
*/
int hdfsRename(hdfsFS fs, const char* oldPath, const char* newPath);
/**
* hdfsGetWorkingDirectory - Get the current working directory for
* the given filesystem.
* @param fs The configured filesystem handle.
* @param buffer The user-buffer to copy path of cwd into.
* @param bufferSize The length of user-buffer.
* @return Returns buffer, NULL on error.
*/
char* hdfsGetWorkingDirectory(hdfsFS fs, char *buffer, size_t bufferSize);
/**
* hdfsSetWorkingDirectory - Set the working directory. All relative
* paths will be resolved relative to it.
* @param fs The configured filesystem handle.
* @param path The path of the new 'cwd'.
* @return Returns 0 on success, -1 on error.
*/
int hdfsSetWorkingDirectory(hdfsFS fs, const char* path);
/**
* hdfsCreateDirectory - Make the given file and all non-existent
* parents into directories.
* @param fs The configured filesystem handle.
* @param path The path of the directory.
* @return Returns 0 on success, -1 on error.
*/
int hdfsCreateDirectory(hdfsFS fs, const char* path);
/**
* hdfsSetReplication - Set the replication of the specified
* file to the supplied value
* @param fs The configured filesystem handle.
* @param path The path of the file.
* @return Returns 0 on success, -1 on error.
*/
int hdfsSetReplication(hdfsFS fs, const char* path, int16_t replication);
/**
* hdfsFileInfo - Information about a file/directory.
*/
typedef struct {
tObjectKind mKind; /* file or directory */
char *mName; /* the name of the file */
tTime mLastMod; /* the last modification time for the file in seconds */
tOffset mSize; /* the size of the file in bytes */
short mReplication; /* the count of replicas */
tOffset mBlockSize; /* the block size for the file */
char *mOwner; /* the owner of the file */
char *mGroup; /* the group associated with the file */
short mPermissions; /* the permissions associated with the file */
tTime mLastAccess; /* the last access time for the file in seconds */
} hdfsFileInfo;
/**
* hdfsListDirectory - Get list of files/directories for a given
* directory-path. hdfsFreeFileInfo should be called to deallocate memory.
* @param fs The configured filesystem handle.
* @param path The path of the directory.
* @param numEntries Set to the number of files/directories in path.
* @return Returns a dynamically-allocated array of hdfsFileInfo
* objects; NULL on error.
*/
hdfsFileInfo *hdfsListDirectory(hdfsFS fs, const char* path,
int *numEntries);
/**
* hdfsGetPathInfo - Get information about a path as a (dynamically
* allocated) single hdfsFileInfo struct. hdfsFreeFileInfo should be
* called when the pointer is no longer needed.
* @param fs The configured filesystem handle.
* @param path The path of the file.
* @return Returns a dynamically-allocated hdfsFileInfo object;
* NULL on error.
*/
hdfsFileInfo *hdfsGetPathInfo(hdfsFS fs, const char* path);
/**
* hdfsFreeFileInfo - Free up the hdfsFileInfo array (including fields)
* @param hdfsFileInfo The array of dynamically-allocated hdfsFileInfo
* objects.
* @param numEntries The size of the array.
*/
void hdfsFreeFileInfo(hdfsFileInfo *hdfsFileInfo, int numEntries);
/**
* hdfsGetHosts - Get hostnames where a particular block (determined by
* pos & blocksize) of a file is stored. The last element in the array
* is NULL. Due to replication, a single block could be present on
* multiple hosts.
* @param fs The configured filesystem handle.
* @param path The path of the file.
* @param start The start of the block.
* @param length The length of the block.
* @return Returns a dynamically-allocated 2-d array of blocks-hosts;
* NULL on error.
*/
char*** hdfsGetHosts(hdfsFS fs, const char* path,
tOffset start, tOffset length);
/**
* hdfsFreeHosts - Free up the structure returned by hdfsGetHosts
* @param hdfsFileInfo The array of dynamically-allocated hdfsFileInfo
* objects.
* @param numEntries The size of the array.
*/
void hdfsFreeHosts(char ***blockHosts);
/**
* hdfsGetDefaultBlockSize - Get the default blocksize.
*
* @param fs The configured filesystem handle.
* @deprecated Use hdfsGetDefaultBlockSizeAtPath instead.
*
* @return Returns the default blocksize, or -1 on error.
*/
tOffset hdfsGetDefaultBlockSize(hdfsFS fs);
/**
* hdfsGetDefaultBlockSizeAtPath - Get the default blocksize at the
* filesystem indicated by a given path.
*
* @param fs The configured filesystem handle.
* @param path The given path will be used to locate the actual
* filesystem. The full path does not have to exist.
*
* @return Returns the default blocksize, or -1 on error.
*/
tOffset hdfsGetDefaultBlockSizeAtPath(hdfsFS fs, const char *path);
/**
* hdfsGetCapacity - Return the raw capacity of the filesystem.
* @param fs The configured filesystem handle.
* @return Returns the raw-capacity; -1 on error.
*/
tOffset hdfsGetCapacity(hdfsFS fs);
/**
* hdfsGetUsed - Return the total raw size of all files in the filesystem.
* @param fs The configured filesystem handle.
* @return Returns the total-size; -1 on error.
*/
tOffset hdfsGetUsed(hdfsFS fs);
/**
* Change the user and/or group of a file or directory.
*
* @param fs The configured filesystem handle.
* @param path the path to the file or directory
* @param owner User string. Set to NULL for 'no change'
* @param group Group string. Set to NULL for 'no change'
* @return 0 on success else -1
*/
int hdfsChown(hdfsFS fs, const char* path, const char *owner,
const char *group);
/**
* hdfsChmod
* @param fs The configured filesystem handle.
* @param path the path to the file or directory
* @param mode the bitmask to set it to
* @return 0 on success else -1
*/
int hdfsChmod(hdfsFS fs, const char* path, short mode);
/**
* hdfsUtime
* @param fs The configured filesystem handle.
* @param path the path to the file or directory
* @param mtime new modification time or -1 for no change
* @param atime new access time or -1 for no change
* @return 0 on success else -1
*/
int hdfsUtime(hdfsFS fs, const char* path, tTime mtime, tTime atime);
/**
* Allocate a zero-copy options structure.
*
* You must free all options structures allocated with this function using
* hadoopRzOptionsFree.
*
* @return A zero-copy options structure, or NULL if one could
* not be allocated. If NULL is returned, errno will
* contain the error number.
*/
struct hadoopRzOptions *hadoopRzOptionsAlloc(void);
/**
* Determine whether we should skip checksums in read0.
*
* @param opts The options structure.
* @param skip Nonzero to skip checksums sometimes; zero to always
* check them.
*
* @return 0 on success; -1 plus errno on failure.
*/
int hadoopRzOptionsSetSkipChecksum(
struct hadoopRzOptions *opts, int skip);
/**
* Set the ByteBufferPool to use with read0.
*
* @param opts The options structure.
* @param className If this is NULL, we will not use any
* ByteBufferPool. If this is non-NULL, it will be
* treated as the name of the pool class to use.
* For example, you can use
* ELASTIC_BYTE_BUFFER_POOL_CLASS.
*
* @return 0 if the ByteBufferPool class was found and
* instantiated;
* -1 plus errno otherwise.
*/
int hadoopRzOptionsSetByteBufferPool(
struct hadoopRzOptions *opts, const char *className);
/**
* Free a hadoopRzOptionsFree structure.
*
* @param opts The options structure to free.
* Any associated ByteBufferPool will also be freed.
*/
void hadoopRzOptionsFree(struct hadoopRzOptions *opts);
/**
* Perform a byte buffer read.
* If possible, this will be a zero-copy (mmap) read.
*
* @param file The file to read from.
* @param opts An options structure created by hadoopRzOptionsAlloc.
* @param maxLength The maximum length to read. We may read fewer bytes
* than this length.
*
* @return On success, we will return a new hadoopRzBuffer.
* This buffer will continue to be valid and readable
* until it is released by readZeroBufferFree. Failure to
* release a buffer will lead to a memory leak.
* You can access the data within the hadoopRzBuffer with
* hadoopRzBufferGet. If you have reached EOF, the data
* within the hadoopRzBuffer will be NULL. You must still
* free hadoopRzBuffer instances containing NULL.
*
* On failure, we will return NULL plus an errno code.
* errno = EOPNOTSUPP indicates that we could not do a
* zero-copy read, and there was no ByteBufferPool
* supplied.
*/
struct hadoopRzBuffer* hadoopReadZero(hdfsFile file,
struct hadoopRzOptions *opts, int32_t maxLength);
/**
* Determine the length of the buffer returned from readZero.
*
* @param buffer a buffer returned from readZero.
* @return the length of the buffer.
*/
int32_t hadoopRzBufferLength(const struct hadoopRzBuffer *buffer);
/**
* Get a pointer to the raw buffer returned from readZero.
*
* To find out how many bytes this buffer contains, call
* hadoopRzBufferLength.
*
* @param buffer a buffer returned from readZero.
* @return a pointer to the start of the buffer. This will be
* NULL when end-of-file has been reached.
*/
const void *hadoopRzBufferGet(const struct hadoopRzBuffer *buffer);
/**
* Release a buffer obtained through readZero.
*
* @param file The hdfs stream that created this buffer. This must be
* the same stream you called hadoopReadZero on.
* @param buffer The buffer to release.
*/
void hadoopRzBufferFree(hdfsFile file, struct hadoopRzBuffer *buffer);
#ifdef __cplusplus
}
#endif
#endif /*LIBHDFS_HDFS_H*/
/**
* vim: ts=4: sw=4: et
*/
