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STAR(4L)                    Schilys USER COMMANDS                    STAR(4L)



NAME
       star(1,4) - tape archive file(1,n) format

DESCRIPTION
       Tar  Archives  are layered archives.  The basic structure is defined by
       the POSIX.1-1988 archive format and documented in(1,8) the BASIC TAR  HEADER
       DESCRIPTION  section  below.   The higher level structure is defined by
       the POSIX.1-2001 extended headers and documented in(1,8)  the  EXTENDED  TAR
       (PAX)  HEADER  STRUCTURE  section below.  POSIX.1-2001 extended headers
       are pseudo files that contain an unlimited number  of  extended  header
       keywords  and  associated values. The header keywords are documented in(1,8)
       the EXTENDED TAR (PAX) HEADER KEYWORDS section below.

BASIC TAR HEADER DESCRIPTION
       Physically, a POSIX.1-1988 tar archive consists of a  series  of  fixed
       sized  blocks of TBLOCK (512) characters.  It contains a series of file(1,n)
       entries terminated by a logical end-of-archive marker,  which  consists
       of two blocks of 512 bytes of binary zeroes.  Each file(1,n) entry is repre-
       sented by a header block that describes the file(1,n)  followed  by  one  or
       more  blocks  with  the content of the file. The length of each file(1,n) is
       rounded up to a multiple of 512 bytes.

       A number of TBLOCK sizes blocks are grouped together to a  tape  record
       for  physical I/O operations. Each record of n blocks is written with a
       single write(1,2)(2) operation.  On magnetic tapes, this results in(1,8) a single
       tape record.

       The header block is defined in(1,8) star.h as follows:
       /*
        * POSIX.1-1988 field size values and magic.
        */
       #define   TBLOCK         512
       #define   NAMSIZ         100
       #define   PFXSIZ         155

       #define   TMODLEN        8
       #define   TUIDLEN        8
       #define   TGIDLEN        8
       #define   TSIZLEN        12
       #define   TMTMLEN        12
       #define   TCKSLEN        8

       #define   TMAGIC         "ustar"   /* ustar magic(4,5) 6 chars + '\0' */
       #define   TMAGLEN        6         /* "ustar" including '\0' */
       #define   TVERSION       "00"
       #define   TVERSLEN       2
       #define   TUNMLEN        32
       #define   TGNMLEN        32
       #define   TDEVLEN        8

       /*
        * POSIX.1-1988 typeflag values
        */
       #define   REGTYPE        '0'  /* Regular File          */
       #define   AREGTYPE       '\0' /* Regular File (outdated) */
       #define   LNKTYPE        '1'  /* Hard Link             */
       #define   SYMTYPE        '2'  /* Symbolic Link         */
       #define   CHRTYPE        '3'  /* Character Special     */
       #define   BLKTYPE        '4'  /* Block Special         */
       #define   DIRTYPE        '5'  /* Directory             */
       #define   FIFOTYPE       '6'  /* FIFO (named(5,8) pipe(2,8))     */
       #define   CONTTYPE       '7'  /* Contiguous File       */

       /*
        * POSIX.1-2001 typeflag extensions.
        * POSIX.1-2001 calls the extended USTAR format PAX although it is
        * definitely derived from and based on USTAR. The reason may be that
        * POSIX.1-2001 calls the tar program outdated and lists the
        * pax program as the successor.
        */
       #define   LF_GHDR        'g'  /* POSIX.1-2001 global extended header */
       #define   LF_XHDR        'x'  /* POSIX.1-2001 extended header */

       See  section  EXTENDED  TAR  (PAX) HEADER KEYWORDS for more information
       about the structure of a POSIX.1-2001 header.

       /*
        * star(1,4)/gnu/Sun tar extensions:
        *
        * Note that the standards committee allows only capital A through
        * capital Z for user-defined expansion.  This means that defining
        * something as, say '8' is a *bad* idea.
        */

       #define   LF_ACL         'A'  /* Solaris Access Control List     */
       #define   LF_DUMPDIR     'D'  /* GNU dump dir                    */
       #define   LF_EXTATTR     'E'  /* Solaris Extended Attribute File */
       #define   LF_META        'I'  /* Inode (metadata only) no file(1,n) content */
       #define   LF_LONGLINK    'K'  /* NEXT file(1,n) has a long linkname   */
       #define   LF_LONGNAME    'L'  /* NEXT file(1,n) has a long name       */
       #define   LF_MULTIVOL    'M'  /* Continuation file(1,n) rest to be skipped */
       #define   LF_NAMES       'N'  /* OLD GNU for names > 100 characters   */
       #define   LF_SPARSE      'S'  /* This is for sparse files        */
       #define   LF_VOLHDR      'V'  /* tape/volume header Ignore on extraction */
       #define   LF_VU_XHDR     'X'  /* POSIX.1-2001 xtended (Sun VU version(1,3,5)) */

       /*
        * Definitions for the t_mode field
        */
       #define   TSUID     04000     /* Set UID on execution  */
       #define   TSGID     02000     /* Set GID on execution  */
       #define   TSVTX     01000     /* On directories, restricted deletion flag */
       #define   TUREAD    00400     /* Read by owner         */
       #define   TUWRITE   00200     /* Write by owner special */
       #define   TUEXEC    00100     /* Execute/search by owner */
       #define   TGREAD    00040     /* Read by group         */
       #define   TGWRITE   00020     /* Write by group        */
       #define   TGEXEC    00010     /* Execute/search by group */
       #define   TOREAD    00004     /* Read by other         */
       #define   TOWRITE   00002     /* Write by other        */
       #define   TOEXEC    00001     /* Execute/search by other */

       #define   TALLMODES 07777     /* The low 12 bits       */

       /*
        * This is the ustar (Posix 1003.1) header.
        */
       struct header {
            char t_name[NAMSIZ];     /*   0 Filename               */
            char t_mode[8];          /* 100 Permissions            */
            char t_uid[8];           /* 108 Numerical User ID      */
            char t_gid[8];           /* 116 Numerical Group ID     */
            char t_size[12];         /* 124 Filesize               */
            char t_mtime[12];        /* 136 st_mtime               */
            char t_chksum[8];        /* 148 Checksum               */
            char t_typeflag;         /* 156 Typ of File            */
            char t_linkname[NAMSIZ]; /* 157 Target of Links        */
            char t_magic[TMAGLEN];   /* 257 "ustar"                */
            char t_version[TVERSLEN]; /* 263 Version fixed to 00   */
            char t_uname[TUNMLEN];   /* 265 User Name              */
            char t_gname[TGNMLEN];   /* 297 Group Name             */
            char t_devmajor[8];      /* 329 Major for devices      */
            char t_devminor[8];      /* 337 Minor for devices      */
            char t_prefix[PFXSIZ];   /* 345 Prefix for t_name      */
                                     /* 500 End                    */
            char t_mfill[12];        /* 500 Filler up to 512       */
       };

       /*
        * star(1,4) header specific definitions
        */
       #define   STMAGIC        "tar"     /* star(1,4) magic(4,5) */
       #define   STMAGLEN       4         /* "tar" including '\0' */

       /*
        * This is the new (post Posix 1003.1-1988) xstar header
        * defined in(1,8) 1994.
        *
        * t_prefix[130]    is guaranteed to be ' ' to prevent ustar
        *                  compliant implementations from failing.
        * t_mfill & t_xmagic need to be zero for a 100% ustar compliant
        *                  implementation, so setting t_xmagic to
        *                  "tar" should be avoided in(1,8) the future.
        *
        * A different method to recognize this format is to verify(1,8) that
        * t_prefix[130]              is equal to ' ' and
        * t_atime[0]/t_ctime[0]      is an octal number and
        * t_atime[11]                is equal to ' ' and
        * t_ctime[11]                is equal to ' '.
        *
        * Note that t_atime[11]/t_ctime[11] may be changed in(1,8) future.
        */
       struct xstar_header {
            char t_name[NAMSIZ];     /*   0 Filename               */
            char t_mode[8];          /* 100 Permissions            */
            char t_uid[8];           /* 108 Numerical User ID      */
            char t_gid[8];           /* 116 Numerical Group ID     */
            char t_size[12];         /* 124 Filesize               */
            char t_mtime[12];        /* 136 st_mtime               */
            char t_chksum[8];        /* 148 Checksum               */
            char t_typeflag;         /* 156 Typ of File            */
            char t_linkname[NAMSIZ]; /* 157 Target of Links        */
            char t_magic[TMAGLEN];   /* 257 "ustar"                */
            char t_version[TVERSLEN]; /* 263 Version fixed to 00   */
            char t_uname[TUNMLEN];   /* 265 User Name              */
            char t_gname[TGNMLEN];   /* 297 Group Name             */
            char t_devmajor[8];      /* 329 Major for devices      */
            char t_devminor[8];      /* 337 Minor for devices      */
            char t_prefix[131];      /* 345 Prefix for t_name      */
            char t_atime[12];        /* 476 st_atime               */
            char t_ctime[12];        /* 488 st_ctime               */
            char t_mfill[8];         /* 500 Filler up to star(1,4) magic(4,5)     */
            char t_xmagic[4];        /* 508 "tar"                  */
       };

       struct sparse {
            char t_offset[12];
            char t_numbytes[12];
       };

       #define   SPARSE_EXT_HDR  21

       struct xstar_ext_header {
            struct sparse t_sp[21];
            char t_isextended;
       };

       typedef union hblock {
            char dummy[TBLOCK];
            long ldummy[TBLOCK/sizeof (long)]; /* force long alignment */
            struct header            dbuf;
            struct xstar_header      xstar_dbuf;
            struct xstar_ext_header  xstar_ext_dbuf;
       } TCB;

       For maximum portability, all  fields  that  contain  character  strings
       should be limited to use the low 7 bits of a character.

       The  name,  linkname  and  prefix  field contain character strings. The
       strings are null terminated except when they use the full space of  100
       characters  for  the  name  or linkname field or 155 characters for the
       prefix field.

       If the prefix does not start with a null  character,  then  prefix  and
       name  need  to  be  concatenated  by using the prefix, followed a slash
       character followed by the name field.  If a null character  appears  in(1,8)
       name  or  prefix before the maximum size is reached, the field in(1,8) ques-
       tion is terminated.  This way file(1,n) names up to 256  characters  may  be
       archived.   The prefix is not used together with the linkname field, so
       the maximum length of a link(1,2) name is 100 characters.

       The fields magic(4,5), uname(1,2) and gname  contain  null  terminated  character
       strings.

       The  version(1,3,5) field contains the string(3,n) "00" without a trailing zero. It
       cannot be set(7,n,1 builtins) to different values as POSIX.1-1988 did not specify a way
       to  handle  different  version(1,3,5)  strings.  The typeflag field contains a
       single character.

       All numeric fields contain size-1  leading  zero-filled  numbers  using
       octal  digits.   They are followed by one or more space or null charac-
       ters.  All recent implementations only use one space or null  character
       at the end of a numerical field to get maximum space for the octal num-
       ber.  Star always uses a space character as terminator.  Numeric fields
       with 8 characters may hold up to 7 octal digits (7777777) which results
       is a maximum value of 2097151.  Numeric fields with 12  characters  may
       hold  up  to  11  octal digits (77777777777) which results is a maximum
       value of 8589934591.

       Star implements a vendor specific (and thus non-POSIX) extension to put
       bigger  numbers  into  the numeric fields. This is done by using a base
       256 coding.  The top bit of the first character in(1,8)  the  appropriate  8
       character  or  12  character field is set(7,n,1 builtins) to flag non octal coding.  If
       base 256 coding is in(1,8) use, then all remaining characters  are  used  to
       code  the  number.  This  results  in(1,8)  7 base 256 digits in(1,8) 8 character
       fields and in(1,8) 11 base 256 digits in(1,8) 12 character fields.  All base  256
       numbers  are two's complement numbers. A base 256 number in(1,8) a 8 charac-
       ter field may hold 56 bits, a base 256 number in(1,8) a 12  character  field
       may  hold  88 bits. This may extended to 64 bits for 8 character fields
       and to 95 bits for 12 character fields. For a negative number the first
       character currently is set(7,n,1 builtins) to a value of 255 (all 8 bits are set(7,n,1 builtins)).  The
       rightmost character in(1,8) a 8 or 12 character  field  contains  the  least
       significant  base  256  number.   Recent GNU tar versions implement the
       same extension.

       While the POSIX standard makes obvious that the fields mode, uid, gid,
       size,  chksum, devmajor and devminor should be treated as unsigned num-
       bers, there is no such definition for the time(1,2,n) field.

       The mode field contains 12 bits holding permissions, see above for  the
       definitions for each of the permission bits.

       The uid and gid fields contain the numerical user id of the file.

       The size field contains the size of the file(1,n) in(1,8) characters.  If the tar
       header is followed by file(1,n) data, then the amount of data  that  follows
       is computed by (size + 511) / 512.

       The mtime filed contains the number of seconds since Jan 1st 1970 00:00
       UTC as retrived via stat(1,2)(2) in(1,8) st_mtime.

       The chksum field contains a simple  checksum  over  all  bytes  of  the
       header.  To compute the value, all characters in(1,8) the header are treated
       as unsigned integers and the characters in(1,8) the chksum field are treated
       as  if(3,n)  they were all spaces. When the computation starts, the checksum
       value is initialized to 0.

       The typeflag field specifies the type of the file(1,n) that is archived.  If
       a  specific  tar implementation does not include support for a specific
       typeflag value, this implementation will extract the unknown file(1,n) types
       as if(3,n) they were plain files.

       '0' REGTYPE
              A  regular  file.  If the size field is non zero, then file(1,n) data
              follows the header.

       '\0' AREGTYPE
              For backwards compatibility with pre POSIX.1-1988 tar  implemen-
              tations,  a nul character is also recognized as marker for plain
              files.  It is not generated by recent tar  implementations.   If
              the size field is non zero, then file(1,n) data follows the header.

       '1' LNKTYPE
              The  file(1,n)  is a hard link(1,2) to another file.  The name of the file(1,n)
              that the file(1,n) is linked to  is  in(1,8)  the  linkname  part  of  the
              header.   For tar archives written by pre POSIX.1-1988 implemen-
              tations, the size field usually contains the size  of  the  file(1,n)
              and  needs to be ignored as no data may follow this header type.
              For POSIX.1-1988 compliant archives, the size field needs to  be
              0.   For  POSIX.1-2001 compliant archives, the size field may be
              non zero, indicating that file(1,n) data is included in(1,8) the  archive.

       '2' SYMTYPE
              The  file(1,n)  is  a symbolic link(1,2) to another file.  The name of the
              file(1,n) that the file(1,n) is linked to is in(1,8) the linkname part  of  the
              header.   The size field needs to be 0.  No file(1,n) data may follow
              the header.

       '3' CHRTYPE
              A character special file.  The fields devmajor and devminor con-
              tain information that defines the file.  The meaning of the size
              field is unspecified by the POSIX standard.  No  file(1,n)  data  may
              follow the header.

       '4' BLKTYPE
              A  block special file.  The fields devmajor and devminor contain
              information that defines the file.   The  meaning  of  the  size
              field  is  unspecified  by the POSIX standard.  No file(1,n) data may
              follow the header.

       '5' DIRTYPE
              A directory or sub directory. Old (pre POSIX.1-1988) tar  imple-
              mentations  did  use  the same typeflag value as for plain files
              and added a slash to the name.  If the size field  is  non  zero
              then  it indicates the maximum size in(1,8) characters the system may
              allocate for this directory. If the size field is  0,  then  the
              system  shall  not limit the size of the directory. On operating
              systems where the disk allocation is not  done  on  a  directory
              base, the size field is ignored on extraction.  No file(1,n) data may
              follow the header.

       '6' FIFOTYPE
              A named(5,8) pipe.  The meaning of the size field is  unspecified  by
              the  POSIX  standard.  The size field must be ignored on extrac-
              tion.  No file(1,n) data may follow the header.

       '7' CONTTYPE
              A contiguous file.  This is a file(1,n) that  gives  special  perfor-
              mance  attributes.   Operating  systems  that don't support this
              file(1,n) type extract this file(1,n) type as plain files.   If  the  size
              field is non zero, then file(1,n) data follows the header.

       'g' GLOBAL POSIX.1-2001 HEADER
              With  POSIX.1-2001  pax  archives,  this  type  defines a global
              extended header.  The size is always non zero  and  denotes  the
              sum  of the length fields in(1,8) the extended header data.  The data
              that follows the header is in(1,8) the pax  extended  header  format.
              The  extended header records in(1,8) this header type affect all fol-
              lowing files in(1,8) the archive unless they are overwritten  by  new
              values.  See EXTENDED TAR (PAX) HEADER FORMAT section below.

       'x' EXTENDED POSIX.1-2001 HEADER
              With  POSIX.1-2001  pax  archives, this type defines an extended
              header.  The size is always non zero and denotes the sum of  the
              length  fields  in(1,8) the extended header data.  The data that fol-
              lows the header is in(1,8)  the  pax  extended  header  format.   The
              extended header records in(1,8) this header type only affect the fol-
              lowing file(1,n) in(1,8) the archive.  See EXTENDED TAR (PAX) HEADER  FOR-
              MAT section below.

       'A' - 'Z'
              Reserved for vendor specific implementations.

       'A'    A  Solaris ACL entry as used by the tar implementation from Sun.
              The size is always non zero and denotes the length of  the  data
              that  follows  the header.  Star currently is not able to handle
              this header type.

       'D'    A GNU dump directory.  This header type is not created  by  star(1,4)
              and handled like a directory during an extract operation, so the
              content is ignored by star(1,4).  The size field denotes  the  length
              of the data that follows the header.

       'E'    A  Solaris  Extended Attribute File.  The size field denotes the
              length of the data that follows the header.  Star  currently  is
              not able to handle this header type.

       'I'    A inode metadata entry.  This header type is used by star(1,4) to ar-
              chive inode meta data only.  To archive  more  inode  meta  data
              than possible with a POSIX-1.1988 tar header, a header with type
              'I' is usually preceded by a 'x' header.  It is used with incre-
              mental  backups.   The  size field holds the length of the file.
              No file(1,n) data follows this header.

       'K'    A long link(1,2) name.  Star is able to read(2,n,1 builtins) and write(1,2) this  type  of
              header.  With  the  xustar  and exustar formats, star(1,4) prefers to
              store long link(1,2) names using the POSIX.1-2001 method.   The  size
              is  always non zero and denotes the length of the long link(1,2) name
              including the trailing null byte. The link(1,2) name is in(1,8)  the  data
              that follows the header.

       'L'    A  long  file(1,n) name.  Star is able to read(2,n,1 builtins) and write(1,2) this type of
              header. With the xustar and exustar  formats,  star(1,4)  prefers  to
              store  long  file(1,n) names using the POSIX.1-2001 method.  The size
              is always non zero and denotes the length of the long file(1,n)  name
              including  the  trailing null byte. The file(1,n) name is in(1,8) the data
              that follows the header.

       'M'    A multi volume continuation entry.  It is used by star(1,4)  to  tell
              the  extraction program via the size field when the next regular
              archive header will follow.  This  allows  to  start  extracting
              multi volume archives with a volume number greater than one.  It
              is used by GNU tar to verify(1,8) multi volume continuation  volumes.
              Other  fields  in(1,8) the GNU multi volume continuation header are a
              result of a GNU tar miss conception and cannot be used.  If  the
              size  field is non zero the data following the header is skipped
              by star(1,4) if(3,n) the volume that starts with  it  is  mounted  as  the
              first  volume.  This header is ignored if(3,n) the volume that starts
              with it is mounted as continuation volume.

       'N'    An outdated linktype used by old GNU tar versions to store  long
              file(1,n) names.  This type is unsupported by star(1,4).

       'S'    A sparse file.  This header type is used by star(1,4) and GNU tar.  A
              sparse header is uses instead of a plain file(1,n) header to denote a
              sparse  file(1,n)  that follows. Directly after the header, a list of
              sparse hole descriptors follows followed by the  compacted  file(1,n)
              data.   With star(1,4) formats, the size field holds a size that rep-
              resents the sum of the sparse hole descriptors plus the size  of
              the  compacted  file(1,n) data. This allows other tar implementations
              to correctly skip to the next tar header.  With GNU tar, up to 4
              sparse  hole descriptors fit into the sparse header.  Additional
              hole descriptors are not needed if(3,n) the  file(1,n)  has  less(1,3)  than  4
              holes.   With  GNU tar, the size field breaks general tar header
              rules and is meaningless because the size  of  the  sparse  hole
              descriptors does not count.

       'V'    A  volume  header.  The name field is is used to hold the volume
              name.  Star uses the atime field to hold the  volume  number  in(1,8)
              case there is no POSIX.1-2001 extended header.  This header type
              is used by star(1,4) and GNU tar.  If the size field is non zero  the
              data following the header is skipped by star(1,4).

       'X'    A  vendor  unique  variant  of  the POSIX.1-2001 extended header
              type.  It has been implemented by  Sun  many  years  before  the
              POSIX.1-2001  standard has been approved.  See also the typeflag
              'x' header type.  Star is able to read(2,n,1 builtins) and write(1,2)  this  type  of
              header.

EXTENDED TAR (PAX) HEADER STRUCTURE
       Block type                            Description

       Ustar Header [typeflag='g']      Global Extended Header
       Global Extended Data
       Ustar Header [typeflag='h']         Extended Header
       Extended Data
       Ustar header [typeflag='0']    File with Extended Header
       Data for File #1
       Ustar header [typeflag='0']   File without Extended Header
       Data for File #2
       Block of binary zeroes              First EOF Block
       Block of binary zeroes              Second EOF Block


EXTENDED TAR (PAX) HEADER FORMAT
       The  data  block that follows a tar archive header with typeflag 'g' or
       'x' contains one or more records in(1,8) the following format:

              "%d %s=%s\n", <length>, <keyword>, <value>

       Each record starts with a a decimal length field. The  length  includes
       the  total  size  of a record including the length field itself and the
       trailing new line.

       The keyword may not include an equal sign.  All keywords beginning with
       lower  case letters and digits are reserved for future use by the POSIX
       standard.

       If the value field is of zero length, it deletes any  header  field  of
       the same name that is in(1,8) effect from the same extended header or from a
       previous global header.

       Null characters do not delimit any value. The value is only limited  by
       its implicit length.

EXTENDED TAR (PAX) HEADER KEYWORDS
       POSIX.1-2001  extended  pax  header  keywords. All numerical values are
       represented as decimal strings.  All texts  are  represented  as  7-bit
       ascii(1,7) or UTF-8:

       atime  The  time(1,2,n)  from  st_atime  in(1,8) sub second granularity.  Star cur-
              rently supports a nanosecond granularity.

       charset
              The name of the character set(7,n,1 builtins) used to encode  the  data  in(1,8)  the
              following file(1,n)(s).  This keyword is currently ignored by star(1,4).

       comment
              Any  number  of  characters  that  should be treated as comment.
              Star ignores the comment as documented by the POSIX standard.

       ctime  The time(1,2,n) from st_ctime in(1,8) sub  second  granularity.   Star  cur-
              rently supports a nanosecond granularity.

       gid    The group ID of the group that owns the file.  The argument is a
              decimal number.  This field is used if(3,n) the group ID of a file(1,n) is
              greater than 2097151 (octal 7777777).

       gname  The  group  name  of the following file(1,n)(s) coded in(1,8) UTF-8 if(3,n) the
              group name does  not  fit  into  323  characters  or  cannot  be
              expressed in(1,8) 7-Bit ASCII.

       linkpath
              The name of the linkpath coded in(1,8) UTF-8 if(3,n) it is longer than 100
              characters or cannot be expressed in(1,8) 7-Bit ASCII.

       mtime  The time(1,2,n) from st_mtime in(1,8) sub  second  granularity.   Star  cur-
              rently supports a nanosecond granularity.

       path   The  name of the linkpath coded in(1,8) UTF-8 if(3,n) it does not fit into
              100 characters + 155 characters prefix or cannot be expressed in(1,8)
              7-Bit ASCII.

       realtime.any
              The  keywords  prefixed  by  realtime.   are reserved for future
              standardization.

       security.any
              The keywords prefixed by  security.   are  reserved  for  future
              standardization.

       size   The  size  of  the  file(1,n)  as  decimal number if(3,n) the file(1,n) size is
              greater than 8589934591 (octal 77777777777).  The  size  keyword
              may  not  refer to the real file(1,n) size but is related to the size
              if(3,n) the file(1,n) in(1,8) the archive.  See also SCHILY.realsize  for  more
              information.

       uid    The  uid  ID of the group that owns the file.  The argument is a
              decimal number.  This field is used if(3,n) the uid ID of a  file(1,n)  is
              greater than 2097151 (octal 7777777).

       uname(1,2)  The  user  name  of  the following file(1,n)(s) coded in(1,8) UTF-8 if(3,n) the
              user name  does  not  fit  into  323  characters  or  cannot  be
              expressed in(1,8) 7-Bit ASCII.

       VENDOR.keyword
              Any keyword that starts with a vendor name in(1,8) capital letters is
              reserved for vendor specific extensions by the  standard.   Star
              uses  a  lot  of  these vendor specific extension. See below for
              more informations.

SCHILY PAX EXTENSION KEYWORDS
       Star uses own vendor specific extensions. The  SCHILY  vendor  specific
       extended pax header keywords are:

       SCHILY.acl.access
              The ACL for a file.

              Since  no  official backup format for POSIX access(2,5) control lists
              has been  defined,  star(1,4)  uses  the  vendor  defined  attributes
              SCHILY.acl.access and SCHILY.acl.default for storing the ACL and
              Default ACL of a file(1,n), respectively.  The access(2,5)  control  lists
              are  stored  in(1,8)  the short text form as defined in(1,8) POSIX 1003.1e
              draft standard 17.

              To each named(5,8) user ACL entry  a  fourth  colon  separated  field
              field  containing  the  user  identifier (UID) of the associated
              user is appended.  To each named(5,8) group entry a fourth colon sep-
              arated  field containing the group identifier (GID) of the asso-
              ciated group is appended.   (POSIX  1003.1e  draft  standard  17
              allows to add fields to ACL entries.)

              This  is  an example of the format used for SCHILY.acl.access (a
              space has been inserted after the equal sign and lines are  bro-
              ken  [marked  with  '\'  ] for readability, additional fields in(1,8)
              bold):

              SCHILY.acl.access= user::rwx,user:lisa:r-x:502, \
                                 group::r-x,group:toolies:rwx:102, \
                                 mask::rwx,other::r--x

              The numerical user and  group  identifiers  are  essential  when
              restoring  a  system  completely from a backup, as initially the
              name-to-identifier mappings may not be available, and then  file(1,n)
              ownership restoration would not work.

              As the archive format that is used for backing up access(2,5) control
              lists is compatible with the pax archive format,  archives  cre-
              ated  that way can be restored by star(1,4) or a POSIX.1-2001 compli-
              ant pax.  Note that programs other than star(1,4) will ignore the ACL
              information.

       SCHILY.acl.default
              The  default  ACL  for  a  file.  See SCHILY.acl.access for more
              information.

              This is an example of the format used for SCHILY.acl.default  (a
              space  has been inserted after the equal sign and lines are bro-
              ken [marked with '\' ] for  readability,  additional  fields  in(1,8)
              bold):

              SCHILY.acl.default= user::rwx,user:lisa:r-x:502, \
                                  group::r-x,mask::r-x,other::r-x

       SCHILY.ddev
              The  device  ids for names used is the SCHILY.dir dump directory
              list from st_dev of the file(1,n) as decimal number.  The SCHILY.ddev
              keyword  is followed by a space separated list of device id num-
              bers. Each corresponds exactly to a name in(1,8) the  list  found  in(1,8)
              SCHILY.dir.  If a specific device id number is repeated, a comma
              (,) without a following space may be use to denote that the cur-
              rent device id number is identical to the previous number.  This
              keyword is used in(1,8) dump mode.  This keyword is not yet used.

       SCHILY.dev
              The device id from st_dev of the file(1,n) as decimal  number.   This
              keyword is used in(1,8) dump mode.

       SCHILY.devmajor
              The  device  major  number  of  the file(1,n) if(3,n) it is a character or
              block special file.  The argument is  a  decimal  number.   This
              field  is  used  if(3,n) the device major of the file(1,n) is greater than
              2097151 (octal 7777777).

       SCHILY.devminor
              The device minor number of the file(1,n) if(3,n)  it  is  a  character  or
              block  special  file.   The  argument is a decimal number.  This
              field is used if(3,n) the device minor of the file(1,n)  is  greater  than
              2097151 (octal 7777777).

       SCHILY.dino
              The  inode  numbers for names used is the SCHILY.dir dump direc-
              tory list from st_ino  of  the  file(1,n)  as  decimal  number.   The
              SCHILY.dino  keyword  is  followed  by a space separated list of
              inode numbers. Each corresponds exactly to a name  in(1,8)  the  list
              found in(1,8) SCHILY.dir.  This keyword is used in(1,8) dump mode.

       SCHILY.dir
              A  list  of  filenames  (the content) for the current directory.
              The names are coded in(1,8) UTF-8.  Each file(1,n) name is prefixed  by  a
              single character that is used as a flag.  Each file(1,n) name is lim-
              ited by a null character.  The null character is  directly  fol-
              lowed  by  he  flag character for the next file(1,n) name in(1,8) case the
              list is not terminated by the current file(1,n) name.  The flag char-
              acter  must  not  be  a null character.  By default, a ^A (octal
              001) is used.  The following flags are defined:

              \000   This is the list terminator character - the  second  null
                     byte, see below.

              ^A     The  default  flag that is used in(1,8) case the dump dir fea-
                     tures have not been active.

              Y      A non directory file(1,n) that is in(1,8) the current (incremental)
                     dump.

              N      A  non  directory file(1,n) that is not in(1,8) the current (incre-
                     mental) dump.

              D      A directory that is in(1,8) the current (incremental) dump.

              d      A directory that is  not  in(1,8)  the  current  (incremental)
                     dump.

              The  list is terminated by two successive null bytes.  The first
              is the null byte for the last file(1,n) name.  The second  null  byte
              is  at the position where a flag character would be expected, it
              acts ad a list terminator. The length  tag  for  the  SCHILY.dir
              data includes both null bytes.

              If  a  dump  mode has been selected that writes compact complete
              directory information to the beginning of the archive, the  flag
              character  may contain values different from ^A.  Star implemen-
              tations up to star-1.5 do not include this feature.  Tar  imple-
              mentations  that  like  to read(2,n,1 builtins) archives that use the SCHILY.dir
              keyword, shall not rely on values other than \000 (^@)  or  \001
              (^A).

              This keyword is used in(1,8) dump mode.

       SCHILY.fflags
              A  textual  version(1,3,5) of the BSD or Linux extended file(1,n) flags.  As
              this tag has not yet been documented, please look(1,8,3 Search::Dict) into the  star(1,4)
              source, file(1,n) fflags.c for more information.

       SCHILY.filetype
              A  textual  version(1,3,5) of the real file(1,n) type of the file.  The fol-
              lowing names are used:

              unallocated             An unknown  file(1,n)  type  that  may  be  a
                                      result  of  a unlink(1,2)(2) operation.  This
                                      should never happen.

              regular                 A regular file.

              contiguous              A contiguous file. On operating  systems
                                      or  file(1,n) systems that don't support this
                                      file(1,n) type, it is handled like a  regular
                                      file.

              symlink                 A symbolic link(1,2) to any file(1,n) type.

              directory               A directory.

              character special       A character special file.

              block special           A block special file.

              fifo                    A named(5,8) pipe.

              socket(2,7,n)                  A UNIX domain socket.

              mpx character special   A multiplexed character special file.

              mpx block special       A multiplexed block special file.

              XENIX nsem              A XENIX named(5,8) semaphore.

              XENIX nshd              XENIX shared data.

              door                    A Solaris door.

              eventcount              A UNOS event count.

              whiteout                A BSD whiteout directory entry.

              sparse                  A sparse regular file.

              volheader               A volume header.

              unknown/bad             Any   other  unknown  file(1,n)  type.   This
                                      should never happen.


       SCHILY.ino
              The inode number from st_ino of  the  file(1,n)  as  decimal  number.
              This keyword is used in(1,8) dump mode.

       SCHILY.nlink
              The  link(1,2)  count of the file(1,n) as decimal number.  This keyword is
              used in(1,8) dump mode.

       SCHILY.offset
              The offset value for a multi volume continuation  header.   This
              keyword  is  used with multi volume continuation headers.  Multi
              volume continuation headers are used to allow to start reading a
              multi volume archive past the first volume.

       SCHILY.realsize
              The  real  size  of the file(1,n) as decimal number.  This keyword is
              used if(3,n) the real size of the file(1,n) differs from the visible  size
              of the file(1,n) in(1,8) the archive.  The real file(1,n) size differs from the
              size in(1,8) the archive if(3,n) the file(1,n) type is sparse or if(3,n) the file(1,n) is
              a  continuation  file(1,n)  on  a  multi volume archive.  In case the
              SCHILY.realsize keyword is needed, it must be past any size key-
              word in(1,8) case a size keyword is also present.

       SCHILY.tarfiletype
              The  following additional file(1,n) types are used in(1,8) SCHILY.tarfile-
              type:

              hardlink
                     A hard link(1,2) to any file(1,n) type.

              dumpdir
                     A directory with dump entries

              multivol continuation
                     A multi volume continuation for any file(1,n) type.

              meta   A meta entry (inode meta data only) for any file(1,n) type.

       SCHILY.xattr.attr(1,5)
              A  POSIX.1-2001  coded  version(1,3,5)  of  the  Linux  extended   file(1,n)
              attributes.   Linux  extended  file(1,n)  attributes  are  name/value
              pairs. Every attribute name results in(1,8) a  SCHILY.xattr.name  tag
              and  the value of the extended attribute is used as the value of
              the POSIX.1-2001 header tag.  Note that this way  of  coding  is
              not portable across platforms.  A version(1,3,5) for BSD may be created
              but Solaris includes far more features with  extended  attribute
              files than Linux does.

              A  future version(1,3,5) of star(1,4) will implement a similar method as the
              tar program on Solaris currently uses. When this  implementation
              is  ready, the SCHILY.xattr.name feature may be removed in(1,8) favor
              of a truly portable implementation that supports Solaris also.


SCHILY 'G'LOBAL PAX EXTENSION KEYWORDS
       The following star(1,4) vendor unique extensions may only appear in(1,8) 'g'lobal
       extended pax headers:

       SCHILY.archtype
              The  textual version(1,3,5) of the archive type used.  The textual val-
              ues used for SCHILY.archtype are the sam of the content  of  the
              first  'g'lobal  pax  header.  Then  the first tape block may be
              scanned to recognize the archive type.

       SCHILY.release
              The textual version(1,3,5) of the star(1,4) version(1,3,5) string(3,n) and the  platform
              name  where  this star(1,4) has been compiled.  The same text appears
              when calling star(1,4) -version.

       SCHILY.volhdr.blockoff
              This keyword is used for multi volume archives.   It  represents
              the offset within the whole archive expressed in(1,8) 512 byte units.

       SCHILY.volhdr.blocksize
              The tape blocksize expressed in(1,8) 512 byte  units(1,7)  that  was  used
              when writing the archive.

       SCHILY.volhdr.cwd
              This  keyword  is used in(1,8) dump mode.  It is only used to contain
              the real backup working directory if(3,n) the fs-name= option of star(1,4)
              is used to overwrite the SCHILY.volhdr.filesys value.  Overwrit-
              ing SCHILY.volhdr.filesys is needed when backups are run on file(1,n)
              system snapshots rather than on the real file(1,n) system.

       SCHILY.volhdr.device
              This  keyword  is  used in(1,8) dump mode.  It represents the name of
              the device that holds the file(1,n) system data. For disk based  file(1,n)
              systems, this is the device name of the mounted device.

              This  keyword  is  optional.  It helps to correctly identify the
              file(1,n) system from which this dump has been made.

       SCHILY.volhdr.dumpdate
              This keyword is used in(1,8) dump mode.  It represents the  time(1,2,n)  the
              current dump did start.

       SCHILY.volhdr.dumplevel
              This  keyword  is used in(1,8) dump mode.  It represents the level of
              the current dump.  Dump levels are  small  numbers,  the  lowest
              possible  number  is  0.  Dump level 0 represents a full backup.
              Dump level 1 represents a backup that contains all changes  that
              did  occur since the last level 0 dump.  Dump level 2 represents
              a backup that contains all changes that did occur since the last
              level  1  dump.   Star  does  not specify a maximum allowed dump
              level but you should try to keep the numbers less(1,3) than 100.

       SCHILY.volhdr.dumptype
              This keyword is used in(1,8) dump mode.  If the dump  is  a  complete
              dump  of a file(1,n) system, then the argument is the text full, else
              the argument is the text partial.

       SCHILY.volhdr.filesys
              This keyword is used in(1,8) dump mode.  It represents the top  level
              directory  for  the  file(1,n)  system  from which this dump has been
              made.  If the dump represents a  dump  that  has  an  associated
              level, then the this directory needs to be identical to the root
              directory of this file(1,n) system which is the mount(2,8) point.

       SCHILY.volhdr.hostname
              This keyword is used in(1,8) dump mode.  The value is retrieved  from
              gethostname(3) or uname(1,2)(2).

       SCHILY.volhdr.label
              The  textual  volume  label.  The volume label must be identical
              within a set(7,n,1 builtins) of multi volume archives.

       SCHILY.volhdr.refdate
              This keyword is used in(1,8) dump mode if(3,n)  the  current  dump  is  an
              incremental  dump  with a level > 0.  It represents the time(1,2,n) the
              related dump did start.

       SCHILY.volhdr.reflevel
              This keyword is used in(1,8) dump mode if(3,n)  the  current  dump  is  an
              incremental  dump  with a level > 0.  It represents the level of
              the related dump.  The related dump is  the  last  dump  with  a
              level that is lower that the level of this dump.  If a dump with
              the level of the current  dump  -1  exists,  then  this  is  the
              related  dump  level.  Otherwise,  the dump level is decremented
              until a valid dump level could be found in(1,8) the dump database.

       SCHILY.volhdr.volume
              This keyword is used for multi volume archives.   It  represents
              the  volume number within a volume set.  The number used for the
              first volume is 1.

MULTI VOLUME ARCHIVE HANDLING
       To be documented in(1,8) the future.

SEE ALSO
NOTES
BUGS
AUTHOR
Joerg Schilling                    05/05/22                           STAR(4L)

References for this manual (incoming links)