tables.h revision 1556
1/*- 2 * Copyright (c) 1992 Keith Muller. 3 * Copyright (c) 1992, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Keith Muller of the University of California, San Diego. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)tables.h 8.1 (Berkeley) 5/31/93 38 */ 39 40/* 41 * data structures and constants used by the different databases kept by pax 42 */ 43 44/* 45 * Hash Table Sizes MUST BE PRIME, if set too small performance suffers. 46 * Probably safe to expect 500000 inodes per tape. Assuming good key 47 * distribution (inodes) chains of under 50 long (worse case) is ok. 48 */ 49#define L_TAB_SZ 2503 /* hard link hash table size */ 50#define F_TAB_SZ 50503 /* file time hash table size */ 51#define N_TAB_SZ 541 /* interactive rename hash table */ 52#define D_TAB_SZ 317 /* unique device mapping table */ 53#define A_TAB_SZ 317 /* ftree dir access time reset table */ 54#define MAXKEYLEN 64 /* max number of chars for hash */ 55 56/* 57 * file hard link structure (hashed by dev/ino and chained) used to find the 58 * hard links in a file system or with some archive formats (cpio) 59 */ 60typedef struct hrdlnk { 61 char *name; /* name of first file seen with this ino/dev */ 62 dev_t dev; /* files device number */ 63 ino_t ino; /* files inode number */ 64 u_long nlink; /* expected link count */ 65 struct hrdlnk *fow; 66} HRDLNK; 67 68/* 69 * Archive write update file time table (the -u, -C flag), hashed by filename. 70 * Filenames are stored in a scratch file at seek offset into the file. The 71 * file time (mod time) and the file name length (for a quick check) are 72 * stored in a hash table node. We were forced to use a scratch file because 73 * with -u, the mtime for every node in the archive must always be available 74 * to compare against (and this data can get REALLY large with big archives). 75 * By being careful to read only when we have a good chance of a match, the 76 * performance loss is not measurable (and the size of the archive we can 77 * handle is greatly increased). 78 */ 79typedef struct ftm { 80 int namelen; /* file name length */ 81 time_t mtime; /* files last modification time */ 82 off_t seek; /* loacation in scratch file */ 83 struct ftm *fow; 84} FTM; 85 86/* 87 * Interactive rename table (-i flag), hashed by orig filename. 88 * We assume this will not be a large table as this mapping data can only be 89 * obtained through interactive input by the user. Nobody is going to type in 90 * changes for 500000 files? We use chaining to resolve collisions. 91 */ 92 93typedef struct namt { 94 char *oname; /* old name */ 95 char *nname; /* new name typed in by the user */ 96 struct namt *fow; 97} NAMT; 98 99/* 100 * Unique device mapping tables. Some protocols (e.g. cpio) require that the 101 * <c_dev,c_ino> pair will uniquely identify a file in an archive unless they 102 * are links to the same file. Appending to archives can break this. For those 103 * protocols that have this requirement we map c_dev to a unique value not seen 104 * in the archive when we append. We also try to handle inode truncation with 105 * this table. (When the inode field in the archive header are too small, we 106 * remap the dev on writes to remove accidental collisions). 107 * 108 * The list is hashed by device number using chain collision resolution. Off of 109 * each DEVT are linked the various remaps for this device based on those bits 110 * in the inode which were truncated. For example if we are just remapping to 111 * avoid a device number during an update append, off the DEVT we would have 112 * only a single DLIST that has a truncation id of 0 (no inode bits were 113 * stripped for this device so far). When we spot inode truncation we create 114 * a new mapping based on the set of bits in the inode which were stripped off. 115 * so if the top four bits of the inode are stripped and they have a pattern of 116 * 0110...... (where . are those bits not truncated) we would have a mapping 117 * assigned for all inodes that has the same 0110.... pattern (with this dev 118 * number of course). This keeps the mapping sparse and should be able to store 119 * close to the limit of files which can be represented by the optimal 120 * combination of dev and inode bits, and without creating a fouled up archive. 121 * Note we also remap truncated devs in the same way (an exercise for the 122 * dedicated reader; always wanted to say that...:) 123 */ 124 125typedef struct devt { 126 dev_t dev; /* the orig device number we now have to map */ 127 struct devt *fow; /* new device map list */ 128 struct dlist *list; /* map list based on inode truncation bits */ 129} DEVT; 130 131typedef struct dlist { 132 ino_t trunc_bits; /* truncation pattern for a specific map */ 133 dev_t dev; /* the new device id we use */ 134 struct dlist *fow; 135} DLIST; 136 137/* 138 * ftree directory access time reset table. When we are done with with a 139 * subtree we reset the access and mod time of the directory when the tflag is 140 * set. Not really explicitly specified in the pax spec, but easy and fast to 141 * do (and this may have even been intended in the spec, it is not clear). 142 * table is hashed by inode with chaining. 143 */ 144 145typedef struct atdir { 146 char *name; /* name of directory to reset */ 147 dev_t dev; /* dev and inode for fast lookup */ 148 ino_t ino; 149 time_t mtime; /* access and mod time to reset to */ 150 time_t atime; 151 struct atdir *fow; 152} ATDIR; 153 154/* 155 * created directory time and mode storage entry. After pax is finished during 156 * extraction or copy, we must reset directory access modes and times that 157 * may have been modified after creation (they no longer have the specified 158 * times and/or modes). We must reset time in the reverse order of creation, 159 * because entries are added from the top of the file tree to the bottom. 160 * We MUST reset times from leaf to root (it will not work the other 161 * direction). Entries are recorded into a spool file to make reverse 162 * reading faster. 163 */ 164 165typedef struct dirdata { 166 int nlen; /* length of the directory name (includes \0) */ 167 off_t npos; /* position in file where this dir name starts */ 168 mode_t mode; /* file mode to restore */ 169 time_t mtime; /* mtime to set */ 170 time_t atime; /* atime to set */ 171 int frc_mode; /* do we force mode settings? */ 172} DIRDATA; 173