This class represents an entry in a Dump archive. It consists of the entry's header, the entry's File and any extended attributes.

DumpEntries that are created from the header bytes read from an archive are instantiated with the DumpArchiveEntry( byte[] ) constructor. These entries will be used when extracting from or listing the contents of an archive. These entries have their header filled in using the header bytes. They also set the File to null, since they reference an archive entry not a file.

DumpEntries can also be constructed from nothing but a name. This allows the programmer to construct the entry by hand, for instance when only an InputStream is available for writing to the archive, and the header information is constructed from other information. In this case the header fields are set to defaults and the File is set to null.

The C structure for a Dump Entry's header is:

#define TP_BSIZE    1024          // size of each file block
#define NTREC       10            // number of blocks to write at once
#define HIGHDENSITYTREC 32        // number of blocks to write on high-density tapes
#define TP_NINDIR   (TP_BSIZE/2)  // number if indirect inodes in record
#define TP_NINOS    (TP_NINDIR / sizeof (int32_t))
#define LBLSIZE     16
#define NAMELEN     64

#define OFS_MAGIC     (int) 60011  // old format magic value
#define NFS_MAGIC     (int) 60012  // new format magic value
#define FS_UFS2_MAGIC (int) 0x19540119
#define CHECKSUM      (int) 84446  // constant used in checksum algorithm

struct  s_spcl {
  int32_t c_type;             // record type (see below)
  int32_t c_date;             // date of this dump
  int32_t c_ddate;            // date of previous dump
  int32_t c_volume;           // dump volume number
  u_int32_t c_tapea;          // logical block of this record
  dump_ino_t c_ino;           // number of inode
  int32_t c_magic;            // magic number (see above)
  int32_t c_checksum;         // record checksum
#ifdef  __linux__
  struct  new_bsd_inode c_dinode;
#else
#ifdef sunos
  struct  new_bsd_inode c_dinode;
#else
  struct  dinode  c_dinode;   // ownership and mode of inode
#endif
#endif
  int32_t c_count;            // number of valid c_addr entries
  union u_data c_data;        // see above
  char    c_label[LBLSIZE];   // dump label
  int32_t c_level;            // level of this dump
  char    c_filesys[NAMELEN]; // name of dumpped file system
  char    c_dev[NAMELEN];     // name of dumpped device
  char    c_host[NAMELEN];    // name of dumpped host
  int32_t c_flags;            // additional information (see below)
  int32_t c_firstrec;         // first record on volume
  int32_t c_ntrec;            // blocksize on volume
  int32_t c_extattributes;    // additional inode info (see below)
  int32_t c_spare[30];        // reserved for future uses
} s_spcl;

//
// flag values
//
#define DR_NEWHEADER     0x0001  // new format tape header
#define DR_NEWINODEFMT   0x0002  // new format inodes on tape
#define DR_COMPRESSED    0x0080  // dump tape is compressed
#define DR_METAONLY      0x0100  // only the metadata of the inode has been dumped
#define DR_INODEINFO     0x0002  // [SIC] TS_END header contains c_inos information
#define DR_EXTATTRIBUTES 0x8000

//
// extattributes inode info
//
#define EXT_REGULAR         0
#define EXT_MACOSFNDRINFO   1
#define EXT_MACOSRESFORK    2
#define EXT_XATTR           3

// used for EA on tape
#define EXT2_GOOD_OLD_INODE_SIZE    128
#define EXT2_XATTR_MAGIC        0xEA020000  // block EA
#define EXT2_XATTR_MAGIC2       0xEA020001  // in inode EA

The fields in bold are the same for all blocks. (This permitted multiple dumps to be written to a single tape.)

The C structure for the inode (file) information is:

struct bsdtimeval {           //  **** alpha-*-linux is deviant
  __u32   tv_sec;
  __u32   tv_usec;
};

#define NDADDR      12
#define NIADDR       3

//
// This is the new (4.4) BSD inode structure
// copied from the FreeBSD 2.0 <ufs/ufs/dinode.h> include file
//
struct new_bsd_inode {
  __u16       di_mode;           // file type, standard Unix permissions
  __s16       di_nlink;          // number of hard links to file.
  union {
     __u16       oldids[2];
     __u32       inumber;
  }           di_u;
  u_quad_t    di_size;           // file size
  struct bsdtimeval   di_atime;  // time file was last accessed
  struct bsdtimeval   di_mtime;  // time file was last modified
  struct bsdtimeval   di_ctime;  // time file was created
  __u32       di_db[NDADDR];
  __u32       di_ib[NIADDR];
  __u32       di_flags;          //
  __s32       di_blocks;         // number of disk blocks
  __s32       di_gen;            // generation number
  __u32       di_uid;            // user id (see /etc/passwd)
  __u32       di_gid;            // group id (see /etc/group)
  __s32       di_spare[2];       // unused
};

It is important to note that the header DOES NOT have the name of the file. It can't since hard links mean that you may have multiple file names for a single physical file. You must read the contents of the directory entries to learn the mapping(s) from file name to inode.

The C structure that indicates if a specific block is a real block that contains data or is a sparse block that is not persisted to the disk is:

#define TP_BSIZE    1024
#define TP_NINDIR   (TP_BSIZE/2)

union u_data {
  char    s_addrs[TP_NINDIR]; // 1 => data; 0 => hole in inode
  int32_t s_inos[TP_NINOS];   // table of first inode on each volume
} u_data;