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Diffstat (limited to 'src/tar.h')
| -rw-r--r-- | src/tar.h | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/src/tar.h b/src/tar.h new file mode 100644 index 0000000..439273e --- /dev/null +++ b/src/tar.h @@ -0,0 +1,331 @@ +/* GNU tar Archive Format description. + + Copyright (C) 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997, + 2000, 2001, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by the + Free Software Foundation; either version 2, or (at your option) any later + version. + + This program is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General + Public License for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* tar Header Block, from POSIX 1003.1-1990. */ + +/* POSIX header. */ + +struct posix_header +{ /* byte offset */ + char name[100]; /* 0 */ + char mode[8]; /* 100 */ + char uid[8]; /* 108 */ + char gid[8]; /* 116 */ + char size[12]; /* 124 */ + char mtime[12]; /* 136 */ + char chksum[8]; /* 148 */ + char typeflag; /* 156 */ + char linkname[100]; /* 157 */ + char magic[6]; /* 257 */ + char version[2]; /* 263 */ + char uname[32]; /* 265 */ + char gname[32]; /* 297 */ + char devmajor[8]; /* 329 */ + char devminor[8]; /* 337 */ + char prefix[155]; /* 345 */ + /* 500 */ +}; + +#define TMAGIC "ustar" /* ustar and a null */ +#define TMAGLEN 6 +#define TVERSION "00" /* 00 and no null */ +#define TVERSLEN 2 + +/* Values used in typeflag field. */ +#define REGTYPE '0' /* regular file */ +#define AREGTYPE '\0' /* regular file */ +#define LNKTYPE '1' /* link */ +#define SYMTYPE '2' /* reserved */ +#define CHRTYPE '3' /* character special */ +#define BLKTYPE '4' /* block special */ +#define DIRTYPE '5' /* directory */ +#define FIFOTYPE '6' /* FIFO special */ +#define CONTTYPE '7' /* reserved */ + +#define XHDTYPE 'x' /* Extended header referring to the + next file in the archive */ +#define XGLTYPE 'g' /* Global extended header */ + +/* Bits used in the mode field, values in octal. */ +#define TSUID 04000 /* set UID on execution */ +#define TSGID 02000 /* set GID on execution */ +#define TSVTX 01000 /* reserved */ + /* file permissions */ +#define TUREAD 00400 /* read by owner */ +#define TUWRITE 00200 /* write by owner */ +#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 */ + +/* tar Header Block, GNU extensions. */ + +/* In GNU tar, SYMTYPE is for to symbolic links, and CONTTYPE is for + contiguous files, so maybe disobeying the `reserved' comment in POSIX + header description. I suspect these were meant to be used this way, and + should not have really been `reserved' in the published standards. */ + +/* *BEWARE* *BEWARE* *BEWARE* that the following information is still + boiling, and may change. Even if the OLDGNU format description should be + accurate, the so-called GNU format is not yet fully decided. It is + surely meant to use only extensions allowed by POSIX, but the sketch + below repeats some ugliness from the OLDGNU format, which should rather + go away. Sparse files should be saved in such a way that they do *not* + require two passes at archive creation time. Huge files get some POSIX + fields to overflow, alternate solutions have to be sought for this. */ + +/* Descriptor for a single file hole. */ + +struct sparse +{ /* byte offset */ + char offset[12]; /* 0 */ + char numbytes[12]; /* 12 */ + /* 24 */ +}; + +/* Sparse files are not supported in POSIX ustar format. For sparse files + with a POSIX header, a GNU extra header is provided which holds overall + sparse information and a few sparse descriptors. When an old GNU header + replaces both the POSIX header and the GNU extra header, it holds some + sparse descriptors too. Whether POSIX or not, if more sparse descriptors + are still needed, they are put into as many successive sparse headers as + necessary. The following constants tell how many sparse descriptors fit + in each kind of header able to hold them. */ + +#define SPARSES_IN_EXTRA_HEADER 16 +#define SPARSES_IN_OLDGNU_HEADER 4 +#define SPARSES_IN_SPARSE_HEADER 21 + +/* Extension header for sparse files, used immediately after the GNU extra + header, and used only if all sparse information cannot fit into that + extra header. There might even be many such extension headers, one after + the other, until all sparse information has been recorded. */ + +struct sparse_header +{ /* byte offset */ + struct sparse sp[SPARSES_IN_SPARSE_HEADER]; + /* 0 */ + char isextended; /* 504 */ + /* 505 */ +}; + +/* The old GNU format header conflicts with POSIX format in such a way that + POSIX archives may fool old GNU tar's, and POSIX tar's might well be + fooled by old GNU tar archives. An old GNU format header uses the space + used by the prefix field in a POSIX header, and cumulates information + normally found in a GNU extra header. With an old GNU tar header, we + never see any POSIX header nor GNU extra header. Supplementary sparse + headers are allowed, however. */ + +struct oldgnu_header +{ /* byte offset */ + char unused_pad1[345]; /* 0 */ + char atime[12]; /* 345 Incr. archive: atime of the file */ + char ctime[12]; /* 357 Incr. archive: ctime of the file */ + char offset[12]; /* 369 Multivolume archive: the offset of + the start of this volume */ + char longnames[4]; /* 381 Not used */ + char unused_pad2; /* 385 */ + struct sparse sp[SPARSES_IN_OLDGNU_HEADER]; + /* 386 */ + char isextended; /* 482 Sparse file: Extension sparse header + follows */ + char realsize[12]; /* 483 Sparse file: Real size*/ + /* 495 */ +}; + +/* OLDGNU_MAGIC uses both magic and version fields, which are contiguous. + Found in an archive, it indicates an old GNU header format, which will be + hopefully become obsolescent. With OLDGNU_MAGIC, uname and gname are + valid, though the header is not truly POSIX conforming. */ +#define OLDGNU_MAGIC "ustar " /* 7 chars and a null */ + +/* The standards committee allows only capital A through capital Z for + user-defined expansion. Other letters in use include: + + 'A' Solaris Access Control List + 'E' Solaris Extended Attribute File + 'I' Inode only, as in 'star' + 'N' Obsolete GNU tar, for file names that do not fit into the main header. + 'X' POSIX 1003.1-2001 eXtended (VU version) */ + +/* This is a dir entry that contains the names of files that were in the + dir at the time the dump was made. */ +#define GNUTYPE_DUMPDIR 'D' + +/* Identifies the *next* file on the tape as having a long linkname. */ +#define GNUTYPE_LONGLINK 'K' + +/* Identifies the *next* file on the tape as having a long name. */ +#define GNUTYPE_LONGNAME 'L' + +/* This is the continuation of a file that began on another volume. */ +#define GNUTYPE_MULTIVOL 'M' + +/* This is for sparse files. */ +#define GNUTYPE_SPARSE 'S' + +/* This file is a tape/volume header. Ignore it on extraction. */ +#define GNUTYPE_VOLHDR 'V' + +/* Solaris extended header */ +#define SOLARIS_XHDTYPE 'X' + +/* J@"org Schilling star header */ + +struct star_header +{ /* byte offset */ + char name[100]; /* 0 */ + char mode[8]; /* 100 */ + char uid[8]; /* 108 */ + char gid[8]; /* 116 */ + char size[12]; /* 124 */ + char mtime[12]; /* 136 */ + char chksum[8]; /* 148 */ + char typeflag; /* 156 */ + char linkname[100]; /* 157 */ + char magic[6]; /* 257 */ + char version[2]; /* 263 */ + char uname[32]; /* 265 */ + char gname[32]; /* 297 */ + char devmajor[8]; /* 329 */ + char devminor[8]; /* 337 */ + char prefix[131]; /* 345 */ + char atime[12]; /* 476 */ + char ctime[12]; /* 488 */ + /* 500 */ +}; + +#define SPARSES_IN_STAR_HEADER 4 +#define SPARSES_IN_STAR_EXT_HEADER 21 + +struct star_in_header +{ + char fill[345]; /* 0 Everything that is before t_prefix */ + char prefix[1]; /* 345 t_name prefix */ + char fill2; /* 346 */ + char fill3[8]; /* 347 */ + char isextended; /* 355 */ + struct sparse sp[SPARSES_IN_STAR_HEADER]; /* 356 */ + char realsize[12]; /* 452 Actual size of the file */ + char offset[12]; /* 464 Offset of multivolume contents */ + char atime[12]; /* 476 */ + char ctime[12]; /* 488 */ + char mfill[8]; /* 500 */ + char xmagic[4]; /* 508 "tar" */ +}; + +struct star_ext_header +{ + struct sparse sp[SPARSES_IN_STAR_EXT_HEADER]; + char isextended; +}; + +/* END */ + + +/* tar Header Block, overall structure. */ + +/* tar files are made in basic blocks of this size. */ +#define BLOCKSIZE 512 + +enum archive_format +{ + DEFAULT_FORMAT, /* format to be decided later */ + V7_FORMAT, /* old V7 tar format */ + OLDGNU_FORMAT, /* GNU format as per before tar 1.12 */ + USTAR_FORMAT, /* POSIX.1-1988 (ustar) format */ + POSIX_FORMAT, /* POSIX.1-2001 format */ + STAR_FORMAT, /* Star format defined in 1994 */ + GNU_FORMAT /* Same as OLDGNU_FORMAT with one exception: + see FIXME note for to_chars() function + (create.c:189) */ +}; + +/* Information about a sparse file. */ +struct sp_array +{ + off_t offset; + size_t numbytes; +}; + +struct xheader +{ + struct obstack *stk; + size_t size; + char *buffer; + uintmax_t string_length; +}; + +struct tar_stat_info +{ + char *orig_file_name; /* name of file read from the archive header */ + char *file_name; /* name of file for the current archive entry + after being normalized. */ + bool had_trailing_slash; /* true if the current archive entry had a + trailing slash before it was normalized. */ + char *link_name; /* name of link for the current archive entry. */ + + char *uname; /* user name of owner */ + char *gname; /* group name of owner */ + struct stat stat; /* regular filesystem stat */ + + /* STAT doesn't always have access, data modification, and status + change times in a convenient form, so store them separately. */ + struct timespec atime; + struct timespec mtime; + struct timespec ctime; + + off_t archive_file_size; /* Size of file as stored in the archive. + Equals stat.st_size for non-sparse files */ + + bool is_sparse; /* Is the file sparse */ + + /* For sparse files: */ + unsigned sparse_major; + unsigned sparse_minor; + size_t sparse_map_avail; /* Index to the first unused element in + sparse_map array. Zero if the file is + not sparse */ + size_t sparse_map_size; /* Size of the sparse map */ + struct sp_array *sparse_map; + + /* Extended headers */ + struct xheader xhdr; + + /* For dumpdirs */ + bool is_dumpdir; /* Is the member a dumpdir? */ + bool skipped; /* The member contents is already read + (for GNUTYPE_DUMPDIR) */ + char *dumpdir; /* Contents of the dump directory */ +}; + +union block +{ + char buffer[BLOCKSIZE]; + struct posix_header header; + struct star_header star_header; + struct oldgnu_header oldgnu_header; + struct sparse_header sparse_header; + struct star_in_header star_in_header; + struct star_ext_header star_ext_header; +}; |