1/*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1992 Keith Muller. 5 * Copyright (c) 1992, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * Keith Muller of the University of California, San Diego. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36/* 37 * data structures and constants used by the different databases kept by pax 38 */ 39 40/* 41 * Hash Table Sizes MUST BE PRIME, if set too small performance suffers. 42 * Probably safe to expect 500000 inodes per tape. Assuming good key 43 * distribution (inodes) chains of under 50 long (worse case) is ok. 44 */ 45#define L_TAB_SZ 2503 /* hard link hash table size */ 46#define F_TAB_SZ 50503 /* file time hash table size */ 47#define N_TAB_SZ 541 /* interactive rename hash table */ 48#define D_TAB_SZ 317 /* unique device mapping table */ 49#define A_TAB_SZ 317 /* ftree dir access time reset table */ 50#define MAXKEYLEN 64 /* max number of chars for hash */ 51 52/* 53 * file hard link structure (hashed by dev/ino and chained) used to find the 54 * hard links in a file system or with some archive formats (cpio) 55 */ 56typedef struct hrdlnk { 57 char *name; /* name of first file seen with this ino/dev */ 58 dev_t dev; /* files device number */ 59 ino_t ino; /* files inode number */ 60 u_long nlink; /* expected link count */ 61 struct hrdlnk *fow; 62} HRDLNK; 63 64/* 65 * Archive write update file time table (the -u, -C flag), hashed by filename. 66 * Filenames are stored in a scratch file at seek offset into the file. The 67 * file time (mod time) and the file name length (for a quick check) are 68 * stored in a hash table node. We were forced to use a scratch file because 69 * with -u, the mtime for every node in the archive must always be available 70 * to compare against (and this data can get REALLY large with big archives). 71 * By being careful to read only when we have a good chance of a match, the 72 * performance loss is not measurable (and the size of the archive we can 73 * handle is greatly increased). 74 */ 75typedef struct ftm { 76 int namelen; /* file name length */ 77 time_t mtime; /* files last modification time */ 78 off_t seek; /* location in scratch file */ 79 struct ftm *fow; 80} FTM; 81 82/* 83 * Interactive rename table (-i flag), hashed by orig filename. 84 * We assume this will not be a large table as this mapping data can only be 85 * obtained through interactive input by the user. Nobody is going to type in 86 * changes for 500000 files? We use chaining to resolve collisions. 87 */ 88 89typedef struct namt { 90 char *oname; /* old name */ 91 char *nname; /* new name typed in by the user */ 92 struct namt *fow; 93} NAMT; 94 95/* 96 * Unique device mapping tables. Some protocols (e.g. cpio) require that the 97 * <c_dev,c_ino> pair will uniquely identify a file in an archive unless they 98 * are links to the same file. Appending to archives can break this. For those 99 * protocols that have this requirement we map c_dev to a unique value not seen 100 * in the archive when we append. We also try to handle inode truncation with 101 * this table. (When the inode field in the archive header are too small, we 102 * remap the dev on writes to remove accidental collisions). 103 * 104 * The list is hashed by device number using chain collision resolution. Off of 105 * each DEVT are linked the various remaps for this device based on those bits 106 * in the inode which were truncated. For example if we are just remapping to 107 * avoid a device number during an update append, off the DEVT we would have 108 * only a single DLIST that has a truncation id of 0 (no inode bits were 109 * stripped for this device so far). When we spot inode truncation we create 110 * a new mapping based on the set of bits in the inode which were stripped off. 111 * so if the top four bits of the inode are stripped and they have a pattern of 112 * 0110...... (where . are those bits not truncated) we would have a mapping 113 * assigned for all inodes that has the same 0110.... pattern (with this dev 114 * number of course). This keeps the mapping sparse and should be able to store 115 * close to the limit of files which can be represented by the optimal 116 * combination of dev and inode bits, and without creating a fouled up archive. 117 * Note we also remap truncated devs in the same way (an exercise for the 118 * dedicated reader; always wanted to say that...:) 119 */ 120 121typedef struct devt { 122 dev_t dev; /* the orig device number we now have to map */ 123 struct devt *fow; /* new device map list */ 124 struct dlist *list; /* map list based on inode truncation bits */ 125} DEVT; 126 127typedef struct dlist { 128 ino_t trunc_bits; /* truncation pattern for a specific map */ 129 dev_t dev; /* the new device id we use */ 130 struct dlist *fow; 131} DLIST; 132 133/* 134 * ftree directory access time reset table. When we are done with with a 135 * subtree we reset the access and mod time of the directory when the tflag is 136 * set. Not really explicitly specified in the pax spec, but easy and fast to 137 * do (and this may have even been intended in the spec, it is not clear). 138 * table is hashed by inode with chaining. 139 */ 140 141typedef struct atdir { 142 char *name; /* name of directory to reset */ 143 dev_t dev; /* dev and inode for fast lookup */ 144 ino_t ino; 145 time_t mtime; /* access and mod time to reset to */ 146 time_t atime; 147 struct atdir *fow; 148} ATDIR; 149 150/* 151 * created directory time and mode storage entry. After pax is finished during 152 * extraction or copy, we must reset directory access modes and times that 153 * may have been modified after creation (they no longer have the specified 154 * times and/or modes). We must reset time in the reverse order of creation, 155 * because entries are added from the top of the file tree to the bottom. 156 * We MUST reset times from leaf to root (it will not work the other 157 * direction). Entries are recorded into a spool file to make reverse 158 * reading faster. 159 */ 160 161typedef struct dirdata { 162 int nlen; /* length of the directory name (includes \0) */ 163 off_t npos; /* position in file where this dir name starts */ 164 mode_t mode; /* file mode to restore */ 165 time_t mtime; /* mtime to set */ 166 time_t atime; /* atime to set */ 167 int frc_mode; /* do we force mode settings? */ 168} DIRDATA; 169