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