1/* $NetBSD: namei.src,v 1.22 2011/01/07 11:25:10 pooka Exp $ */ 2 3/* 4 * Copyright (c) 1985, 1989, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)namei.h 8.5 (Berkeley) 8/20/94 32 */ 33 34#ifndef _SYS_NAMEI_H_ 35#define _SYS_NAMEI_H_ 36 37#include <sys/queue.h> 38#include <sys/mutex.h> 39 40#ifdef _KERNEL 41#include <sys/kauth.h> 42 43/* 44 * Abstraction for a single pathname. 45 * 46 * This contains both the pathname string and (eventually) all 47 * metadata that determines how the path is to be interpreted. 48 * It is an opaque structure; the implementation is in vfs_lookup.c. 49 * 50 * To call namei, first set up a pathbuf with pathbuf_create or 51 * pathbuf_copyin, then do NDINIT(), then call namei, then AFTER THE 52 * STRUCT NAMEIDATA IS DEAD, call pathbuf_destroy. Don't destroy the 53 * pathbuf before you've finished using the nameidata, or mysterious 54 * bad things may happen. 55 * 56 * pathbuf_assimilate is like pathbuf_create but assumes ownership of 57 * the string buffer passed in, which MUST BE of size PATH_MAX and 58 * have been allocated with PNBUF_GET(). This should only be used when 59 * absolutely necessary; e.g. nfsd uses it for loading paths from 60 * mbufs. 61 */ 62struct pathbuf; 63 64struct pathbuf *pathbuf_create(const char *path); 65struct pathbuf *pathbuf_assimilate(char *path); 66int pathbuf_copyin(const char *userpath, struct pathbuf **ret); 67void pathbuf_destroy(struct pathbuf *); 68 69/* get a copy of the (current) path string */ 70void pathbuf_copystring(const struct pathbuf *, char *buf, size_t maxlen); 71 72/* hold a reference copy of the original path string */ 73const char *pathbuf_stringcopy_get(struct pathbuf *); 74void pathbuf_stringcopy_put(struct pathbuf *, const char *); 75 76// XXX remove this 77int pathbuf_maybe_copyin(const char *userpath, enum uio_seg seg, struct pathbuf **ret); 78 79/* 80 * Encapsulation of namei parameters. 81 */ 82struct nameidata { 83 /* 84 * Arguments to namei/lookup. 85 */ 86 struct pathbuf *ni_pathbuf; /* pathname container */ 87 char *ni_pnbuf; /* extra pathname buffer ref (XXX) */ 88 /* 89 * Arguments to lookup. 90 */ 91 struct vnode *ni_rootdir; /* logical root directory */ 92 struct vnode *ni_erootdir; /* emulation root directory */ 93 /* 94 * Results: returned from/manipulated by lookup 95 */ 96 struct vnode *ni_vp; /* vnode of result */ 97 struct vnode *ni_dvp; /* vnode of intermediate directory */ 98 /* 99 * Shared between namei and lookup/commit routines. 100 */ 101 size_t ni_pathlen; /* remaining chars in path */ 102 const char *ni_next; /* next location in pathname */ 103 unsigned int ni_loopcnt; /* count of symlinks encountered */ 104 /* 105 * Lookup parameters: this structure describes the subset of 106 * information from the nameidata structure that is passed 107 * through the VOP interface. 108 */ 109 struct componentname { 110 /* 111 * Arguments to lookup. 112 */ 113 uint32_t cn_nameiop; /* namei operation */ 114 uint32_t cn_flags; /* flags to namei */ 115 kauth_cred_t cn_cred; /* credentials */ 116 /* 117 * Shared between lookup and commit routines. 118 */ 119 const char *cn_nameptr; /* pointer to looked up name */ 120 size_t cn_namelen; /* length of looked up comp */ 121 u_long cn_hash; /* hash val of looked up name */ 122 size_t cn_consume; /* chars to consume in lookup */ 123 } ni_cnd; 124}; 125 126/* 127 * namei operations 128 */ 129NAMEIFL LOOKUP 0 /* perform name lookup only */ 130NAMEIFL CREATE 1 /* setup for file creation */ 131NAMEIFL DELETE 2 /* setup for file deletion */ 132NAMEIFL RENAME 3 /* setup for file renaming */ 133NAMEIFL OPMASK 3 /* mask for operation */ 134/* 135 * namei operational modifier flags, stored in ni_cnd.cn_flags 136 */ 137NAMEIFL LOCKLEAF 0x00000004 /* lock inode on return */ 138NAMEIFL LOCKPARENT 0x00000008 /* want parent vnode returned locked */ 139NAMEIFL TRYEMULROOT 0x00000010 /* try relative to emulation root 140 first */ 141NAMEIFL NOCACHE 0x00000020 /* name must not be left in cache */ 142NAMEIFL FOLLOW 0x00000040 /* follow symbolic links */ 143NAMEIFL NOFOLLOW 0x00000000 /* do not follow symbolic links 144 (pseudo) */ 145NAMEIFL EMULROOTSET 0x00000080 /* emulation root already 146 in ni_erootdir */ 147NAMEIFL NOCHROOT 0x01000000 /* no chroot on abs path lookups */ 148NAMEIFL MODMASK 0x010000fc /* mask of operational modifiers */ 149/* 150 * Namei parameter descriptors. 151 */ 152NAMEIFL NOCROSSMOUNT 0x0000100 /* do not cross mount points */ 153NAMEIFL RDONLY 0x0000200 /* lookup with read-only semantics */ 154NAMEIFL ISDOTDOT 0x0002000 /* current component name is .. */ 155NAMEIFL MAKEENTRY 0x0004000 /* entry is to be added to name cache */ 156NAMEIFL ISLASTCN 0x0008000 /* this is last component of pathname */ 157NAMEIFL ISSYMLINK 0x0010000 /* symlink needs interpretation */ 158NAMEIFL ISWHITEOUT 0x0020000 /* found whiteout */ 159NAMEIFL DOWHITEOUT 0x0040000 /* do whiteouts */ 160NAMEIFL REQUIREDIR 0x0080000 /* must be a directory */ 161NAMEIFL CREATEDIR 0x0200000 /* trailing slashes are ok */ 162NAMEIFL INRENAME 0x0400000 /* operation is a part of ``rename'' */ 163NAMEIFL INRELOOKUP 0x0800000 /* set while inside relookup() */ 164NAMEIFL PARAMASK 0x0efe300 /* mask of parameter descriptors */ 165 166/* 167 * Initialization of an nameidata structure. 168 */ 169#define NDINIT(ndp, op, flags, pathbuf) { \ 170 (ndp)->ni_cnd.cn_nameiop = op; \ 171 (ndp)->ni_cnd.cn_flags = flags; \ 172 (ndp)->ni_pathbuf = pathbuf; \ 173 (ndp)->ni_cnd.cn_cred = kauth_cred_get(); \ 174} 175#endif 176 177/* 178 * This structure describes the elements in the cache of recent 179 * names looked up by namei. NCHNAMLEN is sized to make structure 180 * size a power of two to optimize malloc's. Minimum reasonable 181 * size is 15. 182 */ 183 184#define NCHNAMLEN 31 /* maximum name segment length we bother with */ 185 186/* 187 * Namecache entry. This structure is arranged so that frequently 188 * accessed and mostly read-only data is toward the front, with 189 * infrequently accessed data and the lock towards the rear. The 190 * lock is then more likely to be in a seperate cache line. 191 */ 192struct namecache { 193 LIST_ENTRY(namecache) nc_hash; /* hash chain */ 194 LIST_ENTRY(namecache) nc_vhash; /* directory hash chain */ 195 struct vnode *nc_dvp; /* vnode of parent of name */ 196 struct vnode *nc_vp; /* vnode the name refers to */ 197 int nc_flags; /* copy of componentname's ISWHITEOUT */ 198 char nc_nlen; /* length of name */ 199 char nc_name[NCHNAMLEN]; /* segment name */ 200 void *nc_gcqueue; /* queue for garbage collection */ 201 TAILQ_ENTRY(namecache) nc_lru; /* psuedo-lru chain */ 202 LIST_ENTRY(namecache) nc_dvlist; 203 LIST_ENTRY(namecache) nc_vlist; 204 kmutex_t nc_lock; /* lock on this entry */ 205 int nc_hittime; /* last time scored a hit */ 206}; 207 208#ifdef _KERNEL 209#include <sys/mallocvar.h> 210#include <sys/pool.h> 211 212struct mount; 213struct cpu_info; 214 215extern pool_cache_t pnbuf_cache; /* pathname buffer cache */ 216 217#define PNBUF_GET() pool_cache_get(pnbuf_cache, PR_WAITOK) 218#define PNBUF_PUT(pnb) pool_cache_put(pnbuf_cache, (pnb)) 219 220/* 221 * Typesafe flags for namei_simple. 222 * 223 * This encoding is not optimal but serves the important purpose of 224 * not being type-compatible with the regular namei flags. 225 */ 226struct namei_simple_flags_type; /* Opaque. */ 227typedef const struct namei_simple_flags_type *namei_simple_flags_t; /* Gross. */ 228extern const namei_simple_flags_t 229 NSM_NOFOLLOW_NOEMULROOT, 230 NSM_NOFOLLOW_TRYEMULROOT, 231 NSM_FOLLOW_NOEMULROOT, 232 NSM_FOLLOW_TRYEMULROOT; 233 234/* 235 * namei_simple_* - the simple cases of namei, with no struct 236 * nameidata involved. 237 * 238 * namei_simple_kernel takes a kernel-space path as the first argument. 239 * namei_simple_user takes a user-space path as the first argument. 240 * 241 * A namei call can be converted to namei_simple_* if: 242 * - the second arg to NDINIT is LOOKUP; 243 * - it does not need the parent vnode, nd.ni_dvp; 244 * - the only flags it uses are (NO)FOLLOW and TRYEMULROOT; 245 * - it does not do anything else gross with the contents of nd. 246 */ 247int namei_simple_kernel(const char *, namei_simple_flags_t, struct vnode **); 248int namei_simple_user(const char *, namei_simple_flags_t, struct vnode **); 249 250int namei(struct nameidata *); 251uint32_t namei_hash(const char *, const char **); 252int lookup_for_nfsd(struct nameidata *, struct vnode *, int neverfollow); 253int lookup_for_nfsd_index(struct nameidata *, struct vnode *); 254int relookup(struct vnode *, struct vnode **, struct componentname *, int); 255void cache_purge1(struct vnode *, const struct componentname *, int); 256#define PURGE_PARENTS 1 257#define PURGE_CHILDREN 2 258#define cache_purge(vp) cache_purge1((vp), NULL, PURGE_PARENTS|PURGE_CHILDREN) 259int cache_lookup(struct vnode *, struct vnode **, struct componentname *); 260int cache_lookup_raw(struct vnode *, struct vnode **, 261 struct componentname *); 262int cache_revlookup(struct vnode *, struct vnode **, char **, char *); 263void cache_enter(struct vnode *, struct vnode *, struct componentname *); 264void nchinit(void); 265void nchreinit(void); 266void cache_cpu_init(struct cpu_info *); 267void cache_purgevfs(struct mount *); 268void namecache_print(struct vnode *, void (*)(const char *, ...)); 269 270#endif 271 272/* 273 * Stats on usefulness of namei caches. 274 * XXX: should be 64-bit counters. 275 */ 276struct nchstats { 277 long ncs_goodhits; /* hits that we can really use */ 278 long ncs_neghits; /* negative hits that we can use */ 279 long ncs_badhits; /* hits we must drop */ 280 long ncs_falsehits; /* hits with id mismatch */ 281 long ncs_miss; /* misses */ 282 long ncs_long; /* long names that ignore cache */ 283 long ncs_pass2; /* names found with passes == 2 */ 284 long ncs_2passes; /* number of times we attempt it */ 285 long ncs_revhits; /* reverse-cache hits */ 286 long ncs_revmiss; /* reverse-cache misses */ 287}; 288 289#ifdef _KERNEL 290extern struct nchstats nchstats; 291#endif 292/* #endif !_SYS_NAMEI_H_ (generated by gennameih.awk) */ 293