2 * Copyright (c) 1992 Keith Muller.
3 * Copyright (c) 1992, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * Keith Muller of the University of California, San Diego.
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10 * modification, are permitted provided that the following conditions
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19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
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37 * @(#)tables.h 8.1 (Berkeley) 5/31/93
38 * $FreeBSD: src/bin/pax/tables.h,v 1.7 1999/08/27 23:14:47 peter Exp $
42 * data structures and constants used by the different databases kept by pax
46 * Hash Table Sizes MUST BE PRIME, if set too small performance suffers.
47 * Probably safe to expect 500000 inodes per tape. Assuming good key
48 * distribution (inodes) chains of under 50 long (worse case) is ok.
50 #define L_TAB_SZ 2503 /* hard link hash table size */
51 #define F_TAB_SZ 50503 /* file time hash table size */
52 #define N_TAB_SZ 541 /* interactive rename hash table */
53 #define D_TAB_SZ 317 /* unique device mapping table */
54 #define A_TAB_SZ 317 /* ftree dir access time reset table */
55 #define MAXKEYLEN 64 /* max number of chars for hash */
58 * file hard link structure (hashed by dev/ino and chained) used to find the
59 * hard links in a file system or with some archive formats (cpio)
61 typedef struct hrdlnk {
62 char *name; /* name of first file seen with this ino/dev */
63 dev_t dev; /* files device number */
64 ino_t ino; /* files inode number */
65 u_long nlink; /* expected link count */
70 * Archive write update file time table (the -u, -C flag), hashed by filename.
71 * Filenames are stored in a scratch file at seek offset into the file. The
72 * file time (mod time) and the file name length (for a quick check) are
73 * stored in a hash table node. We were forced to use a scratch file because
74 * with -u, the mtime for every node in the archive must always be available
75 * to compare against (and this data can get REALLY large with big archives).
76 * By being careful to read only when we have a good chance of a match, the
77 * performance loss is not measurable (and the size of the archive we can
78 * handle is greatly increased).
81 int namelen; /* file name length */
82 time_t mtime; /* files last modification time */
83 off_t seek; /* location in scratch file */
88 * Interactive rename table (-i flag), hashed by orig filename.
89 * We assume this will not be a large table as this mapping data can only be
90 * obtained through interactive input by the user. Nobody is going to type in
91 * changes for 500000 files? We use chaining to resolve collisions.
95 char *oname; /* old name */
96 char *nname; /* new name typed in by the user */
101 * Unique device mapping tables. Some protocols (e.g. cpio) require that the
102 * <c_dev,c_ino> pair will uniquely identify a file in an archive unless they
103 * are links to the same file. Appending to archives can break this. For those
104 * protocols that have this requirement we map c_dev to a unique value not seen
105 * in the archive when we append. We also try to handle inode truncation with
106 * this table. (When the inode field in the archive header are too small, we
107 * remap the dev on writes to remove accidental collisions).
109 * The list is hashed by device number using chain collision resolution. Off of
110 * each DEVT are linked the various remaps for this device based on those bits
111 * in the inode which were truncated. For example if we are just remapping to
112 * avoid a device number during an update append, off the DEVT we would have
113 * only a single DLIST that has a truncation id of 0 (no inode bits were
114 * stripped for this device so far). When we spot inode truncation we create
115 * a new mapping based on the set of bits in the inode which were stripped off.
116 * so if the top four bits of the inode are stripped and they have a pattern of
117 * 0110...... (where . are those bits not truncated) we would have a mapping
118 * assigned for all inodes that has the same 0110.... pattern (with this dev
119 * number of course). This keeps the mapping sparse and should be able to store
120 * close to the limit of files which can be represented by the optimal
121 * combination of dev and inode bits, and without creating a fouled up archive.
122 * Note we also remap truncated devs in the same way (an exercise for the
123 * dedicated reader; always wanted to say that...:)
126 typedef struct devt {
127 dev_t dev; /* the orig device number we now have to map */
128 struct devt *fow; /* new device map list */
129 struct dlist *list; /* map list based on inode truncation bits */
132 typedef struct dlist {
133 ino_t trunc_bits; /* truncation pattern for a specific map */
134 dev_t dev; /* the new device id we use */
139 * ftree directory access time reset table. When we are done with with a
140 * subtree we reset the access and mod time of the directory when the tflag is
141 * set. Not really explicitly specified in the pax spec, but easy and fast to
142 * do (and this may have even been intended in the spec, it is not clear).
143 * table is hashed by inode with chaining.
146 typedef struct atdir {
147 char *name; /* name of directory to reset */
148 dev_t dev; /* dev and inode for fast lookup */
150 time_t mtime; /* access and mod time to reset to */
156 * created directory time and mode storage entry. After pax is finished during
157 * extraction or copy, we must reset directory access modes and times that
158 * may have been modified after creation (they no longer have the specified
159 * times and/or modes). We must reset time in the reverse order of creation,
160 * because entries are added from the top of the file tree to the bottom.
161 * We MUST reset times from leaf to root (it will not work the other
162 * direction). Entries are recorded into a spool file to make reverse
166 typedef struct dirdata {
167 int nlen; /* length of the directory name (includes \0) */
168 off_t npos; /* position in file where this dir name starts */
169 mode_t mode; /* file mode to restore */
170 time_t mtime; /* mtime to set */
171 time_t atime; /* atime to set */
172 int frc_mode; /* do we force mode settings? */