Package org.apache.commons.compress.archivers.cpio

Class CpioArchiveEntry

java.lang.Object
org.apache.commons.compress.archivers.cpio.CpioArchiveEntry
All Implemented Interfaces:
ArchiveEntry, CpioConstants
public class CpioArchiveEntry extends Object implements CpioConstants, ArchiveEntry
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

See Also:
This class is not thread-safe

  • Constructor Details

    • CpioArchiveEntry

      public CpioArchiveEntry(File inputFile, 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 - The file to gather information from.
      entryName - The name of this entry.

    • CpioArchiveEntry

      public CpioArchiveEntry(Path inputPath, String entryName, LinkOption... options) throws IOException
      Creates a CpioArchiveEntry with a specified name for a specified file. The format of this entry will be the new format.
      Parameters:
      inputPath - The file to gather information from.
      entryName - The name of this entry.
      options - options indicating how symbolic links are handled.
      Throws:
      IOException - if an I/O error occurs
      Since:
      1.21

    • CpioArchiveEntry

      public CpioArchiveEntry(short format)
      Creates a CpioArchiveEntry with a specified format.
      Parameters:
      format - 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

    • CpioArchiveEntry

      public CpioArchiveEntry(short format, File inputFile, String entryName)
      Creates a CpioArchiveEntry with a specified name for a specified file.
      Parameters:
      format - The cpio format for this entry.
      inputFile - The file to gather information from.
      entryName - The name of this entry.

      Possible format values are: 

       CpioConstants.FORMAT_NEW
 CpioConstants.FORMAT_NEW_CRC
 CpioConstants.FORMAT_OLD_BINARY
 CpioConstants.FORMAT_OLD_ASCII
      Since:
      1.1

    • CpioArchiveEntry

      public CpioArchiveEntry(short format, Path inputPath, String entryName, LinkOption... options) throws IOException
      Creates a CpioArchiveEntry with a specified name for a specified path.
      Parameters:
      format - The cpio format for this entry.
      inputPath - The file to gather information from.
      entryName - The name of this entry.

      Possible format values are: 

       CpioConstants.FORMAT_NEW
 CpioConstants.FORMAT_NEW_CRC
 CpioConstants.FORMAT_OLD_BINARY
 CpioConstants.FORMAT_OLD_ASCII
      options - options indicating how symbolic links are handled.
      Throws:
      IOException - if an I/O error occurs
      Since:
      1.21

    • CpioArchiveEntry

      public CpioArchiveEntry(short format, String name)
      Creates a CpioArchiveEntry with a specified name.
      Parameters:
      format - The cpio format for this entry.
      name - The name of this entry.

      Possible format values are: 

       CpioConstants.FORMAT_NEW
 CpioConstants.FORMAT_NEW_CRC
 CpioConstants.FORMAT_OLD_BINARY
 CpioConstants.FORMAT_OLD_ASCII
      Since:
      1.1

    • CpioArchiveEntry

      public CpioArchiveEntry(short format, String name, long size)
      Creates a CpioArchiveEntry with a specified name.
      Parameters:
      format - The cpio format for this entry.
      name - The name of this entry.
      size - The size of this entry

      Possible format values are: 

       CpioConstants.FORMAT_NEW
 CpioConstants.FORMAT_NEW_CRC
 CpioConstants.FORMAT_OLD_BINARY
 CpioConstants.FORMAT_OLD_ASCII
      Since:
      1.1

    • CpioArchiveEntry

      public CpioArchiveEntry(String name)
      Creates a CpioArchiveEntry with a specified name. The format of this entry will be the new format.
      Parameters:
      name - The name of this entry.

    • CpioArchiveEntry

      public CpioArchiveEntry(String name, long size)
      Creates a CpioArchiveEntry with a specified name. The format of this entry will be the new format.
      Parameters:
      name - The name of this entry.
      size - The size of this entry

  • Method Details

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • getAlignmentBoundary

      public int getAlignmentBoundary()
      Gets the alignment boundary for this CPIO format
      Returns:
      the alignment boundary (0, 2, 4) in bytes

    • getChksum

      public long getChksum()
      Gets the checksum. Only supported for the new formats.
      Returns:
      the checksum.
      Throws:
      UnsupportedOperationException - if the format is not a new format

    • getDataPadCount

      public int getDataPadCount()
      Gets the number of bytes needed to pad the data to the alignment boundary.
      Returns:
      the number of bytes needed to pad the data (0,1,2,3)

    • getDevice

      public long getDevice()
      Gets the device id.
      Returns:
      the device id.
      Throws:
      UnsupportedOperationException - if this method is called for a CpioArchiveEntry with a new format.

    • getDeviceMaj

      public long getDeviceMaj()
      Gets the major device id.
      Returns:
      the major device id.
      Throws:
      UnsupportedOperationException - if this method is called for a CpioArchiveEntry with an old format.

    • getDeviceMin

      public long getDeviceMin()
      Gets the minor device id
      Returns:
      the minor device id.
      Throws:
      UnsupportedOperationException - if format is not a new format

    • getFormat

      public short getFormat()
      Gets the format for this entry.
      Returns:
      the format.

    • getGID

      public long getGID()
      Gets the group id.
      Returns:
      the group id.

    • getHeaderPadCount

      @Deprecated public int getHeaderPadCount()
      Deprecated.
      This method doesn't properly work for multi-byte encodings. And creates corrupt archives. Use getHeaderPadCount(Charset) or getHeaderPadCount(long) in any case.
      Gets the number of bytes needed to pad the header to the alignment boundary.
      Returns:
      the number of bytes needed to pad the header (0,1,2,3)

    • getHeaderPadCount

      public int getHeaderPadCount(Charset charset)
      Gets the number of bytes needed to pad the header to the alignment boundary.
      Parameters:
      charset - The character set used to encode the entry name in the stream.
      Returns:
      the number of bytes needed to pad the header (0,1,2,3)
      Since:
      1.18

    • getHeaderPadCount

      public int getHeaderPadCount(long nameSize)
      Gets the number of bytes needed to pad the header to the alignment boundary.
      Parameters:
      nameSize - The length of the name in bytes, as read in the stream. Without the trailing zero byte.
      Returns:
      the number of bytes needed to pad the header (0,1,2,3)
      Since:
      1.18

    • getHeaderSize

      public int getHeaderSize()
      Gets the header size for this CPIO format
      Returns:
      the header size in bytes.

    • getInode

      public long getInode()
      Sets the inode.
      Returns:
      the inode.

    • getLastModifiedDate

      public Date getLastModifiedDate()
      Description copied from interface: ArchiveEntry
      Gets the last modified date of this entry.
      Specified by:
      getLastModifiedDate in interface ArchiveEntry
      Returns:
      the last modified date of this entry.

    • getMode

      public long getMode()
      Gets the mode of this entry (e.g. directory, regular file).
      Returns:
      the mode.

    • getName

      public String getName()
      Gets the name.

      This method returns the raw name as it is stored inside of the archive.

      Specified by:
      getName in interface ArchiveEntry
      Returns:
      the name.

    • getNumberOfLinks

      public long getNumberOfLinks()
      Gets the number of links.
      Returns:
      the number of links.

    • getRemoteDevice

      public long getRemoteDevice()
      Gets the remote device id.
      Returns:
      the remote device id.
      Throws:
      UnsupportedOperationException - if this method is called for a CpioArchiveEntry with a new format.

    • getRemoteDeviceMaj

      public long getRemoteDeviceMaj()
      Gets the remote major device id.
      Returns:
      the remote major device id.
      Throws:
      UnsupportedOperationException - if this method is called for a CpioArchiveEntry with an old format.

    • getRemoteDeviceMin

      public long getRemoteDeviceMin()
      Gets the remote minor device id.
      Returns:
      the remote minor device id.
      Throws:
      UnsupportedOperationException - if this method is called for a CpioArchiveEntry with an old format.

    • getSize

      public long getSize()
      Gets the filesize.
      Specified by:
      getSize in interface ArchiveEntry
      Returns:
      the filesize.
      See Also:

    • getTime

      public long getTime()
      Gets the time in seconds.
      Returns:
      the time.

    • getUID

      public long getUID()
      Gets the user id.
      Returns:
      the user id.

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • isBlockDevice

      public boolean isBlockDevice()
      Checks if this entry represents a block device.
      Returns:
      TRUE if this entry is a block device.

    • isCharacterDevice

      public boolean isCharacterDevice()
      Checks if this entry represents a character device.
      Returns:
      TRUE if this entry is a character device.

    • isDirectory

      public boolean isDirectory()
      Checks if this entry represents a directory.
      Specified by:
      isDirectory in interface ArchiveEntry
      Returns:
      TRUE if this entry is a directory.

    • isNetwork

      public boolean isNetwork()
      Checks if this entry represents a network device.
      Returns:
      TRUE if this entry is a network device.

    • isPipe

      public boolean isPipe()
      Checks if this entry represents a pipe.
      Returns:
      TRUE if this entry is a pipe.

    • isRegularFile

      public boolean isRegularFile()
      Checks if this entry represents a regular file.
      Returns:
      TRUE if this entry is a regular file.

    • isSocket

      public boolean isSocket()
      Checks if this entry represents a socket.
      Returns:
      TRUE if this entry is a socket.

    • isSymbolicLink

      public boolean isSymbolicLink()
      Checks if this entry represents a symbolic link.
      Returns:
      TRUE if this entry is a symbolic link.

    • setChksum

      public void setChksum(long chksum)
      Sets the checksum. The checksum is calculated by adding all bytes of a file to transfer (crc += buf[pos] & 0xFF).
      Parameters:
      chksum - The checksum to set.

    • setDevice

      public void setDevice(long device)
      Sets the device id.
      Parameters:
      device - The device id to set.
      Throws:
      UnsupportedOperationException - if this method is called for a CpioArchiveEntry with a new format.

    • setDeviceMaj

      public void setDeviceMaj(long maj)
      Sets major device id.
      Parameters:
      maj - The major device id to set.

    • setDeviceMin

      public void setDeviceMin(long min)
      Sets the minor device id
      Parameters:
      min - The minor device id to set.

    • setGID

      public void setGID(long gid)
      Sets the group id.
      Parameters:
      gid - The group id to set.

    • setInode

      public void setInode(long inode)
      Sets the inode.
      Parameters:
      inode - The inode to set.

    • setMode

      public void setMode(long mode)
      Sets the mode of this entry (e.g. directory, regular file).
      Parameters:
      mode - The mode to set.

    • setName

      public void setName(String name)
      Sets the name.
      Parameters:
      name - The name to set.

    • setNumberOfLinks

      public void setNumberOfLinks(long nlink)
      Sets the number of links.
      Parameters:
      nlink - The number of links to set.

    • setRemoteDevice

      public void setRemoteDevice(long device)
      Sets the remote device id.
      Parameters:
      device - The remote device id to set.
      Throws:
      UnsupportedOperationException - if this method is called for a CpioArchiveEntry with a new format.

    • setRemoteDeviceMaj

      public void setRemoteDeviceMaj(long rmaj)
      Sets the remote major device id.
      Parameters:
      rmaj - The remote major device id to set.
      Throws:
      UnsupportedOperationException - if this method is called for a CpioArchiveEntry with an old format.

    • setRemoteDeviceMin

      public void setRemoteDeviceMin(long rmin)
      Sets the remote minor device id.
      Parameters:
      rmin - The remote minor device id to set.
      Throws:
      UnsupportedOperationException - if this method is called for a CpioArchiveEntry with an old format.

    • setSize

      public void setSize(long size)
      Sets the filesize.
      Parameters:
      size - The filesize to set.

    • setTime

      public void setTime(FileTime time)
      Sets the time.
      Parameters:
      time - The time to set.

    • setTime

      public void setTime(long time)
      Sets the time in seconds.
      Parameters:
      time - The time to set.

    • setUID

      public void setUID(long uid)
      Sets the user id.
      Parameters:
      uid - The user id to set.