tables.h revision 8855
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 * $Id: tables.h,v 1.2 1994/09/24 02:56:35 davidg Exp $ 39 */ 40 41/* 42 * data structures and constants used by the different databases kept by pax 43 */ 44 45/* 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. 49 */ 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 */ 56 57/* 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) 60 */ 61typedef 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 */ 66 struct hrdlnk *fow; 67} HRDLNK; 68 69/* 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). 79 */ 80typedef struct ftm { 81 int namelen; /* file name length */ 82 time_t mtime; /* files last modification time */ 83 off_t seek; /* loacation in scratch file */ 84 struct ftm *fow; 85} FTM; 86 87/* 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. 92 */ 93 94typedef struct namt { 95 char *oname; /* old name */ 96 char *nname; /* new name typed in by the user */ 97 struct namt *fow; 98} NAMT; 99 100/* 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). 108 * 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...:) 124 */ 125 126typedef 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 */ 130} DEVT; 131 132typedef struct dlist { 133 ino_t trunc_bits; /* truncation pattern for a specific map */ 134 dev_t dev; /* the new device id we use */ 135 struct dlist *fow; 136} DLIST; 137 138/* 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. 144 */ 145 146typedef struct atdir { 147 char *name; /* name of directory to reset */ 148 dev_t dev; /* dev and inode for fast lookup */ 149 ino_t ino; 150 time_t mtime; /* access and mod time to reset to */ 151 time_t atime; 152 struct atdir *fow; 153} ATDIR; 154 155/* 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 163 * reading faster. 164 */ 165 166typedef 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? */ 173} DIRDATA; 174