namei.h revision 22975
1/* 2 * Copyright (c) 1985, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)namei.h 8.5 (Berkeley) 1/9/95 34 * $Id$ 35 */ 36 37#ifndef _SYS_NAMEI_H_ 38#define _SYS_NAMEI_H_ 39 40#include <sys/queue.h> 41 42/* 43 * Encapsulation of namei parameters. 44 */ 45struct nameidata { 46 /* 47 * Arguments to namei/lookup. 48 */ 49 const char *ni_dirp; /* pathname pointer */ 50 enum uio_seg ni_segflg; /* location of pathname */ 51 /* u_long ni_nameiop; namei operation */ 52 /* u_long ni_flags; flags to namei */ 53 /* struct proc *ni_proc; process requesting lookup */ 54 /* 55 * Arguments to lookup. 56 */ 57 /* struct ucred *ni_cred; credentials */ 58 struct vnode *ni_startdir; /* starting directory */ 59 struct vnode *ni_rootdir; /* logical root directory */ 60 /* 61 * Results: returned from/manipulated by lookup 62 */ 63 struct vnode *ni_vp; /* vnode of result */ 64 struct vnode *ni_dvp; /* vnode of intermediate directory */ 65 /* 66 * Shared between namei and lookup/commit routines. 67 */ 68 long ni_pathlen; /* remaining chars in path */ 69 char *ni_next; /* next location in pathname */ 70 u_long ni_loopcnt; /* count of symlinks encountered */ 71 /* 72 * Lookup parameters: this structure describes the subset of 73 * information from the nameidata structure that is passed 74 * through the VOP interface. 75 */ 76 struct componentname { 77 /* 78 * Arguments to lookup. 79 */ 80 u_long cn_nameiop; /* namei operation */ 81 u_long cn_flags; /* flags to namei */ 82 struct proc *cn_proc; /* process requesting lookup */ 83 struct ucred *cn_cred; /* credentials */ 84 /* 85 * Shared between lookup and commit routines. 86 */ 87 char *cn_pnbuf; /* pathname buffer */ 88 char *cn_nameptr; /* pointer to looked up name */ 89 long cn_namelen; /* length of looked up component */ 90 u_long cn_hash; /* hash value of looked up name */ 91 long cn_consume; /* chars to consume in lookup() */ 92 } ni_cnd; 93}; 94 95#ifdef KERNEL 96/* 97 * namei operations 98 */ 99#define LOOKUP 0 /* perform name lookup only */ 100#define CREATE 1 /* setup for file creation */ 101#define DELETE 2 /* setup for file deletion */ 102#define RENAME 3 /* setup for file renaming */ 103#define OPMASK 3 /* mask for operation */ 104/* 105 * namei operational modifier flags, stored in ni_cnd.flags 106 */ 107#define LOCKLEAF 0x0004 /* lock inode on return */ 108#define LOCKPARENT 0x0008 /* want parent vnode returned locked */ 109#define WANTPARENT 0x0010 /* want parent vnode returned unlocked */ 110#define NOCACHE 0x0020 /* name must not be left in cache */ 111#define FOLLOW 0x0040 /* follow symbolic links */ 112#define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */ 113#define MODMASK 0x00fc /* mask of operational modifiers */ 114/* 115 * Namei parameter descriptors. 116 * 117 * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP. 118 * If the caller of namei sets the flag (for example execve wants to 119 * know the name of the program that is being executed), then it must 120 * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must 121 * be freed by either the commit routine or the VOP_ABORT routine. 122 * SAVESTART is set only by the callers of namei. It implies SAVENAME 123 * plus the addition of saving the parent directory that contains the 124 * name in ni_startdir. It allows repeated calls to lookup for the 125 * name being sought. The caller is responsible for releasing the 126 * buffer and for vrele'ing ni_startdir. 127 */ 128#define NOCROSSMOUNT 0x000100 /* do not cross mount points */ 129#define RDONLY 0x000200 /* lookup with read-only semantics */ 130#define HASBUF 0x000400 /* has allocated pathname buffer */ 131#define SAVENAME 0x000800 /* save pathname buffer */ 132#define SAVESTART 0x001000 /* save starting directory */ 133#define ISDOTDOT 0x002000 /* current component name is .. */ 134#define MAKEENTRY 0x004000 /* entry is to be added to name cache */ 135#define ISLASTCN 0x008000 /* this is last component of pathname */ 136#define ISSYMLINK 0x010000 /* symlink needs interpretation */ 137#define ISWHITEOUT 0x020000 /* found whiteout */ 138#define DOWHITEOUT 0x040000 /* do whiteouts */ 139#define WILLBEDIR 0x080000 /* new files will be dirs; allow trailing / */ 140#define ISUNICODE 0x100000 /* current component name is unicode*/ 141#define PARAMASK 0x1fff00 /* mask of parameter descriptors */ 142/* 143 * Initialization of an nameidata structure. 144 */ 145#define NDINIT(ndp, op, flags, segflg, namep, p) { \ 146 (ndp)->ni_cnd.cn_nameiop = op; \ 147 (ndp)->ni_cnd.cn_flags = flags; \ 148 (ndp)->ni_segflg = segflg; \ 149 (ndp)->ni_dirp = namep; \ 150 (ndp)->ni_cnd.cn_proc = p; \ 151} 152#endif 153 154/* 155 * This structure describes the elements in the cache of recent 156 * names looked up by namei. NCHNAMLEN is sized to make structure 157 * size a power of two to optimize malloc's. Minimum reasonable 158 * size is 15. 159 */ 160 161#ifdef NCH_STATISTICS 162#define NCHNAMLEN 23 /* maximum name segment length we bother with */ 163#else 164#define NCHNAMLEN 31 /* maximum name segment length we bother with */ 165#endif 166 167struct namecache { 168 LIST_ENTRY(namecache) nc_hash; /* hash chain */ 169 TAILQ_ENTRY(namecache) nc_lru; /* LRU chain */ 170 struct vnode *nc_dvp; /* vnode of parent of name */ 171 u_long nc_dvpid; /* capability number of nc_dvp */ 172 struct vnode *nc_vp; /* vnode the name refers to */ 173 u_long nc_vpid; /* capability number of nc_vp */ 174#ifdef NCH_STATISTICS 175 u_long nc_nbr; /* a serial number */ 176 u_long nc_hits; /* how many times we got hit */ 177#endif 178 char nc_nlen; /* length of name */ 179 char nc_name[NCHNAMLEN]; /* segment name */ 180}; 181 182#ifdef KERNEL 183extern u_long nextvnodeid; 184extern u_long numcache; 185extern u_long numvnodes; 186 187int namei __P((struct nameidata *ndp)); 188int lookup __P((struct nameidata *ndp)); 189int relookup __P((struct vnode *dvp, struct vnode **vpp, 190 struct componentname *cnp)); 191#endif 192 193/* 194 * Stats on usefulness of namei caches. 195 */ 196struct nchstats { 197 long ncs_goodhits; /* hits that we can really use */ 198 long ncs_neghits; /* negative hits that we can use */ 199 long ncs_badhits; /* hits we must drop */ 200 long ncs_falsehits; /* hits with id mismatch */ 201 long ncs_miss; /* misses */ 202 long ncs_long; /* long names that ignore cache */ 203 long ncs_pass2; /* names found with passes == 2 */ 204 long ncs_2passes; /* number of times we attempt it */ 205}; 206 207extern struct nchstats nchstats; 208 209#endif /* !_SYS_NAMEI_H_ */ 210