text: /*-
   * Copyright (c) 1992 Keith Muller.
   * Copyright (c) 1992, 1993
   *	The Regents of the University of California.  All rights reserved.
   *
   * This code is derived from software contributed to Berkeley by
   * Keith Muller of the University of California, San Diego.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 4. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   *	@(#)tables.h	8.1 (Berkeley) 5/31/93
   * $FreeBSD: soc2013/dpl/head/bin/pax/tables.h 128001 2004-04-06 20:06:54Z markm $
   */
  
  /*
   * data structures and constants used by the different databases kept by pax
   */
  
  /*
   * Hash Table Sizes MUST BE PRIME, if set too small performance suffers.
   * Probably safe to expect 500000 inodes per tape. Assuming good key
   * distribution (inodes) chains of under 50 long (worse case) is ok.
   */
  #define L_TAB_SZ	2503		/* hard link hash table size */
  #define F_TAB_SZ	50503		/* file time hash table size */
  #define N_TAB_SZ	541		/* interactive rename hash table */
  #define D_TAB_SZ	317		/* unique device mapping table */
  #define A_TAB_SZ	317		/* ftree dir access time reset table */
  #define MAXKEYLEN	64		/* max number of chars for hash */
  
  /*
   * file hard link structure (hashed by dev/ino and chained) used to find the
   * hard links in a file system or with some archive formats (cpio)
   */
  typedef struct hrdlnk {
  	char		*name;	/* name of first file seen with this ino/dev */
  	dev_t		dev;	/* files device number */
  	ino_t		ino;	/* files inode number */
  	u_long		nlink;	/* expected link count */
  	struct hrdlnk	*fow;
  } HRDLNK;
  
  /*
   * Archive write update file time table (the -u, -C flag), hashed by filename.
   * Filenames are stored in a scratch file at seek offset into the file. The
   * file time (mod time) and the file name length (for a quick check) are
   * stored in a hash table node. We were forced to use a scratch file because
   * with -u, the mtime for every node in the archive must always be available
   * to compare against (and this data can get REALLY large with big archives).
   * By being careful to read only when we have a good chance of a match, the
   * performance loss is not measurable (and the size of the archive we can
   * handle is greatly increased).
   */
  typedef struct ftm {
  	int		namelen;	/* file name length */
  	time_t		mtime;		/* files last modification time */
  	off_t		seek;		/* location in scratch file */
  	struct ftm	*fow;
  } FTM;
  
  /*
   * Interactive rename table (-i flag), hashed by orig filename.
   * We assume this will not be a large table as this mapping data can only be
   * obtained through interactive input by the user. Nobody is going to type in
   * changes for 500000 files? We use chaining to resolve collisions.
   */
  
  typedef struct namt {
  	char		*oname;		/* old name */
  	char		*nname;		/* new name typed in by the user */
  	struct namt	*fow;
  } NAMT;
  
  /*
   * Unique device mapping tables. Some protocols (e.g. cpio) require that the
   * <c_dev,c_ino> pair will uniquely identify a file in an archive unless they
   * are links to the same file. Appending to archives can break this. For those
   * protocols that have this requirement we map c_dev to a unique value not seen
   * in the archive when we append. We also try to handle inode truncation with
   * this table. (When the inode field in the archive header are too small, we
   * remap the dev on writes to remove accidental collisions).
   *
   * The list is hashed by device number using chain collision resolution. Off of
   * each DEVT are linked the various remaps for this device based on those bits
   * in the inode which were truncated. For example if we are just remapping to
   * avoid a device number during an update append, off the DEVT we would have
   * only a single DLIST that has a truncation id of 0 (no inode bits were
   * stripped for this device so far). When we spot inode truncation we create
   * a new mapping based on the set of bits in the inode which were stripped off.
   * so if the top four bits of the inode are stripped and they have a pattern of
   * 0110...... (where . are those bits not truncated) we would have a mapping
   * assigned for all inodes that has the same 0110.... pattern (with this dev
   * number of course). This keeps the mapping sparse and should be able to store
   * close to the limit of files which can be represented by the optimal
   * combination of dev and inode bits, and without creating a fouled up archive.
   * Note we also remap truncated devs in the same way (an exercise for the
   * dedicated reader; always wanted to say that...:)
   */
  
  typedef struct devt {
  	dev_t		dev;	/* the orig device number we now have to map */
  	struct devt	*fow;	/* new device map list */
  	struct dlist	*list;	/* map list based on inode truncation bits */
  } DEVT;
  
  typedef struct dlist {
  	ino_t trunc_bits;	/* truncation pattern for a specific map */
  	dev_t dev;		/* the new device id we use */
  	struct dlist *fow;
  } DLIST;
  
  /*
   * ftree directory access time reset table. When we are done with with a
   * subtree we reset the access and mod time of the directory when the tflag is
   * set. Not really explicitly specified in the pax spec, but easy and fast to
   * do (and this may have even been intended in the spec, it is not clear).
   * table is hashed by inode with chaining.
   */
  
  typedef struct atdir {
  	char *name;	/* name of directory to reset */
  	dev_t dev;	/* dev and inode for fast lookup */
  	ino_t ino;
  	time_t mtime;	/* access and mod time to reset to */
  	time_t atime;
  	struct atdir *fow;
  } ATDIR;
  
  /*
   * created directory time and mode storage entry. After pax is finished during
   * extraction or copy, we must reset directory access modes and times that
   * may have been modified after creation (they no longer have the specified
   * times and/or modes). We must reset time in the reverse order of creation,
   * because entries are added  from the top of the file tree to the bottom.
   * We MUST reset times from leaf to root (it will not work the other
   * direction).  Entries are recorded into a spool file to make reverse
   * reading faster.
   */
  
  typedef struct dirdata {
  	int nlen;	/* length of the directory name (includes \0) */
  	off_t npos;	/* position in file where this dir name starts */
  	mode_t mode;	/* file mode to restore */
  	time_t mtime;	/* mtime to set */
  	time_t atime;	/* atime to set */
  	int frc_mode;	/* do we force mode settings? */
  } DIRDATA;
  