Apache Commons Compress 1.26.0 · org.apache.commons.compress.archivers.cpio.CpioArchiveEntry

A cpio archive consists of a sequence of files. There are several types of headers defined in two categories of new and old format. The headers are recognized by magic numbers:

"070701" ASCII for new portable format
"070702" ASCII for new portable format with CRC
"070707" ASCII for old ASCII (also known as Portable ASCII, odc or old character format
070707 binary for old binary

The old binary format is limited to 16 bits for user id, group id, device, and inode numbers. It is limited to 4 gigabyte file sizes. The old ASCII format is limited to 18 bits for the user id, group id, device, and inode numbers. It is limited to 8 gigabyte file sizes. The new ASCII format is limited to 4 gigabyte file sizes. CPIO 2.5 knows also about tar, but it is not recognized here.

OLD FORMAT

Each file has a 76 (ascii) / 26 (binary) byte header, a variable length, NUL terminated file name, and variable length file data. A header for a file name "TRAILER!!!" indicates the end of the archive.

All the fields in the header are ISO 646 (approximately ASCII) strings of octal numbers, left padded, not NUL terminated.

FIELDNAME        NOTES
c_magic          The integer value octal 070707.  This value can be used to deter-
                 mine whether this archive is written with little-endian or big-
                 endian integers.
c_dev            Device that contains a directory entry for this file
c_ino            I-node number that identifies the input file to the file system
c_mode           The mode specifies both the regular permissions and the file type.
c_uid            Numeric User ID of the owner of the input file
c_gid            Numeric Group ID of the owner of the input file
c_nlink          Number of links that are connected to the input file
c_rdev           For block special and character special entries, this field
                 contains the associated device number.  For all other entry types,
                 it should be set to zero by writers and ignored by readers.
c_mtime[2]       Modification time of the file, indicated as the number of seconds
                 since the start of the epoch, 00:00:00 UTC January 1, 1970.  The
                 four-byte integer is stored with the most-significant 16 bits
                 first followed by the least-significant 16 bits.  Each of the two
                 16 bit values are stored in machine-native byte order.
c_namesize       Length of the path name, including the terminating null byte
c_filesize[2]    Length of the file in bytes. This is the length of the data
                 section that follows the header structure. Must be 0 for
                 FIFOs and directories

All fields are unsigned short fields with 16-bit integer values
apart from c_mtime and c_filesize which are 32-bit integer values

If necessary, the file name and file data are padded with a NUL byte to an even length

Special files, directories, and the trailer are recorded with the h_filesize field equal to 0.

In the ASCII version of this format, the 16-bit entries are represented as 6-byte octal numbers, and the 32-bit entries are represented as 11-byte octal numbers. No padding is added.

NEW FORMAT

Each file has a 110 byte header, a variable length, NUL terminated file name, and variable length file data. A header for a file name "TRAILER!!!" indicates the end of the archive. All the fields in the header are ISO 646 (approximately ASCII) strings of hexadecimal numbers, left padded, not NUL terminated.

FIELDNAME        NOTES
c_magic[6]       The string 070701 for new ASCII, the string 070702 for new ASCII with CRC
c_ino[8]
c_mode[8]
c_uid[8]
c_gid[8]
c_nlink[8]
c_mtim[8]
c_filesize[8]    must be 0 for FIFOs and directories
c_maj[8]
c_min[8]
c_rmaj[8]        only valid for chr and blk special files
c_rmin[8]        only valid for chr and blk special files
c_namesize[8]    count includes terminating NUL in path name
c_check[8]       0 for "new" portable format; for CRC format
                 the sum of all the bytes in the file

New ASCII Format The "new" ASCII format uses 8-byte hexadecimal fields for all numbers and separates device numbers into separate fields for major and minor numbers.

The path name is followed by NUL bytes so that the total size of the fixed header plus path name is a multiple of four. Likewise, the file data is padded to a multiple of four bytes.

This class uses mutable fields and is not considered to be threadsafe.

Based on code from the jRPM project (https://jrpm.sourceforge.net).

The MAGIC numbers and other constants are defined in CpioConstants

N.B. does not handle the cpio "tar" format

Field Summary

Modifier and Type	Field and Description
private final int	alignmentBoundary The boundary to which the header and data elements are aligned: 0, 2 or 4 bytes
private long	chksum
private final short	fileFormat See `CpioArchiveEntry(short)` for possible values.
private long	filesize Number of bytes in the file
private long	gid
private final int	headerSize The number of bytes in each header record; depends on the file format
private long	inode
private long	maj
private long	min
private long	mode
private long	mtime
private String	name
private long	nlink
private long	rmaj
private long	rmin
private long	uid

Constructor Summary

Access	Constructor and Description
public	CpioArchiveEntry(final File The file to gather information from. inputFile, final String The name of this entry. entryName) Creates a CpioArchiveEntry with a specified name for a specified file.
public	CpioArchiveEntry(final Path The file to gather information from. inputPath, final String The name of this entry. entryName, final LinkOption... options indicating how symbolic links are handled. options) Creates a CpioArchiveEntry with a specified name for a specified file.
public	CpioArchiveEntry(final short The cpio format for this entry. Possible format values are: CpioConstants.FORMAT_NEW CpioConstants.FORMAT_NEW_CRC CpioConstants.FORMAT_OLD_BINARY CpioConstants.FORMAT_OLD_ASCII format) Creates a CpioArchiveEntry with a specified format.
public	CpioArchiveEntry(final short The cpio format for this entry. format, final File The file to gather information from. inputFile, final String The name of this entry. Possible format values are: CpioConstants.FORMAT_NEW CpioConstants.FORMAT_NEW_CRC CpioConstants.FORMAT_OLD_BINARY CpioConstants.FORMAT_OLD_ASCII entryName) Creates a CpioArchiveEntry with a specified name for a specified file.
public	CpioArchiveEntry(final short The cpio format for this entry. format, final Path The file to gather information from. inputPath, final String The name of this entry. Possible format values are: CpioConstants.FORMAT_NEW CpioConstants.FORMAT_NEW_CRC CpioConstants.FORMAT_OLD_BINARY CpioConstants.FORMAT_OLD_ASCII entryName, final LinkOption... options indicating how symbolic links are handled. options) Creates a CpioArchiveEntry with a specified name for a specified path.
public	CpioArchiveEntry(final short The cpio format for this entry. format, final String The name of this entry. Possible format values are: CpioConstants.FORMAT_NEW CpioConstants.FORMAT_NEW_CRC CpioConstants.FORMAT_OLD_BINARY CpioConstants.FORMAT_OLD_ASCII name) Creates a CpioArchiveEntry with a specified name.
public	CpioArchiveEntry(final short The cpio format for this entry. format, final String The name of this entry. name, final long The size of this entry Possible format values are: CpioConstants.FORMAT_NEW CpioConstants.FORMAT_NEW_CRC CpioConstants.FORMAT_OLD_BINARY CpioConstants.FORMAT_OLD_ASCII size) Creates a CpioArchiveEntry with a specified name.
public	CpioArchiveEntry(final String The name of this entry. name) Creates a CpioArchiveEntry with a specified name.
public	CpioArchiveEntry(final String The name of this entry. name, final long The size of this entry size) Creates a CpioArchiveEntry with a specified name.

Method Summary

Modifier and Type	Method and Description
private void	checkNewFormat() Checks if the method is allowed for the defined format.
private void	checkOldFormat() Checks if the method is allowed for the defined format.
public boolean	equals(final Object the reference object with which to compare. obj) Overrides java.lang.Object.equals. Indicates whether some other object is "equal to" this one.
public int	Returns: the alignment boundary (0, 2, 4) in bytes getAlignmentBoundary() Gets the alignment boundary for this CPIO format
public long	Returns: the checksum. getChksum() Gets the checksum.
public int	Returns: the number of bytes needed to pad the data (0,1,2,3) getDataPadCount() Gets the number of bytes needed to pad the data to the alignment boundary.
public long	Returns: the device id. getDevice() Gets the device id.
public long	Returns: the major device id. getDeviceMaj() Gets the major device id.
public long	Returns: the minor device id. getDeviceMin() Gets the minor device id
public short	Returns: the format. getFormat() Gets the format for this entry.
public long	Returns: the group id. getGID() Gets the group id.
public int	Returns: the number of bytes needed to pad the header (0,1,2,3) getHeaderPadCount() Deprecated This method doesn't properly work for multi-byte encodings. Gets the number of bytes needed to pad the header to the alignment boundary.
public int	Returns: the number of bytes needed to pad the header (0,1,2,3) getHeaderPadCount(final Charset The character set used to encode the entry name in the stream. charset) Gets the number of bytes needed to pad the header to the alignment boundary.
public int	Returns: the number of bytes needed to pad the header (0,1,2,3) getHeaderPadCount(final long The length of the name in bytes, as read in the stream. Without the trailing zero byte. nameSize) Gets the number of bytes needed to pad the header to the alignment boundary.
public int	Returns: the header size in bytes. getHeaderSize() Gets the header size for this CPIO format
public long	Returns: the inode. getInode() Sets the inode.
public Date	getLastModifiedDate() Implements org.apache.commons.compress.archivers.ArchiveEntry.getLastModifiedDate. Gets the last modified date of this entry.
public long	Returns: the mode. getMode() Gets the mode of this entry (e.g. directory, regular file).
public String	Returns: the name. getName() Implements org.apache.commons.compress.archivers.ArchiveEntry.getName. Gets the name.
public long	Returns: the number of links. getNumberOfLinks() Gets the number of links.
public long	Returns: the remote device id. getRemoteDevice() Gets the remote device id.
public long	Returns: the remote major device id. getRemoteDeviceMaj() Gets the remote major device id.
public long	Returns: the remote minor device id. getRemoteDeviceMin() Gets the remote minor device id.
public long	Returns: the filesize. getSize() Implements org.apache.commons.compress.archivers.ArchiveEntry.getSize. Gets the filesize.
public long	Returns: the time. getTime() Gets the time in seconds.
public long	Returns: the user id. getUID() Gets the user id.
public int	hashCode() Overrides java.lang.Object.hashCode. Returns a hash code value for the object.
public boolean	Returns: TRUE if this entry is a block device. isBlockDevice() Checks if this entry represents a block device.
public boolean	Returns: TRUE if this entry is a character device. isCharacterDevice() Checks if this entry represents a character device.
public boolean	Returns: TRUE if this entry is a directory. isDirectory() Implements org.apache.commons.compress.archivers.ArchiveEntry.isDirectory. Checks if this entry represents a directory.
public boolean	Returns: TRUE if this entry is a network device. isNetwork() Checks if this entry represents a network device.
public boolean	Returns: TRUE if this entry is a pipe. isPipe() Checks if this entry represents a pipe.
public boolean	Returns: TRUE if this entry is a regular file. isRegularFile() Checks if this entry represents a regular file.
public boolean	Returns: TRUE if this entry is a socket. isSocket() Checks if this entry represents a socket.
public boolean	Returns: TRUE if this entry is a symbolic link. isSymbolicLink() Checks if this entry represents a symbolic link.
public void	setChksum(final long The checksum to set. chksum) Sets the checksum.
public void	setDevice(final long The device id to set. device) Sets the device id.
public void	setDeviceMaj(final long The major device id to set. maj) Sets major device id.
public void	setDeviceMin(final long The minor device id to set. min) Sets the minor device id
public void	setGID(final long The group id to set. gid) Sets the group id.
public void	setInode(final long The inode to set. inode) Sets the inode.
public void	setMode(final long The mode to set. mode) Sets the mode of this entry (e.g. directory, regular file).
public void	setName(final String The name to set. name) Sets the name.
public void	setNumberOfLinks(final long The number of links to set. nlink) Sets the number of links.
public void	setRemoteDevice(final long The remote device id to set. device) Sets the remote device id.
public void	setRemoteDeviceMaj(final long The remote major device id to set. rmaj) Sets the remote major device id.
public void	setRemoteDeviceMin(final long The remote minor device id to set. rmin) Sets the remote minor device id.
public void	setSize(final long The filesize to set. size) Sets the filesize.
public void	setTime(final FileTime The time to set. time) Sets the time.
public void	setTime(final long The time to set. time) Sets the time in seconds.
public void	setUID(final long The user id to set. uid) Sets the user id.

Inherited from java.lang.Object:: clone finalize getClass notify notifyAll toString wait wait wait

Field Detail

alignmentBoundary	back to summary
private final int alignmentBoundary The boundary to which the header and data elements are aligned: 0, 2 or 4 bytes

chksum	back to summary
private long chksum

fileFormat	back to summary
private final short fileFormat See `CpioArchiveEntry(short)` for possible values.

filesize	back to summary
private long filesize Number of bytes in the file

gid	back to summary
private long gid

headerSize	back to summary
private final int headerSize The number of bytes in each header record; depends on the file format

inode	back to summary
private long inode

maj	back to summary
private long maj

min	back to summary
private long min

mode	back to summary
private long mode

mtime	back to summary
private long mtime

name	back to summary
private String name

nlink	back to summary
private long nlink

rmaj	back to summary
private long rmaj

rmin	back to summary
private long rmin

uid	back to summary
private long uid

Constructor Detail

CpioArchiveEntry	back to summary
public CpioArchiveEntry(final File inputFile, final String entryName) Creates a CpioArchiveEntry with a specified name for a specified file. The format of this entry will be the new format. Parameters inputFile:File The file to gather information from. entryName:String The name of this entry.

CpioArchiveEntry

public Class CpioArchiveEntry

OLD FORMAT

NEW FORMAT

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail