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