1/* $NetBSD: namei.src,v 1.65 2024/07/01 00:58:05 christos 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#if defined(_KERNEL) || defined(_MODULE) 41#include <sys/kauth.h> 42#include <sys/rwlock.h> 43 44/* 45 * Abstraction for a single pathname. 46 * 47 * This contains both the pathname string and (eventually) all 48 * metadata that determines how the path is to be interpreted. 49 * It is an opaque structure; the implementation is in vfs_lookup.c. 50 * 51 * To call namei, first set up a pathbuf with pathbuf_create or 52 * pathbuf_copyin, then do NDINIT(), then call namei, then AFTER THE 53 * STRUCT NAMEIDATA IS DEAD, call pathbuf_destroy. Don't destroy the 54 * pathbuf before you've finished using the nameidata, or mysterious 55 * bad things may happen. 56 * 57 * pathbuf_assimilate is like pathbuf_create but assumes ownership of 58 * the string buffer passed in, which MUST BE of size PATH_MAX and 59 * have been allocated with PNBUF_GET(). This should only be used when 60 * absolutely necessary; e.g. nfsd uses it for loading paths from 61 * mbufs. 62 */ 63struct pathbuf; 64 65struct pathbuf *pathbuf_create(const char *path); 66struct pathbuf *pathbuf_assimilate(char *path); 67int pathbuf_copyin(const char *userpath, struct pathbuf **ret); 68void pathbuf_destroy(struct pathbuf *); 69 70/* get a copy of the (current) path string */ 71void pathbuf_copystring(const struct pathbuf *, char *buf, size_t maxlen); 72 73/* hold a reference copy of the original path string */ 74const char *pathbuf_stringcopy_get(struct pathbuf *); 75void pathbuf_stringcopy_put(struct pathbuf *, const char *); 76 77// XXX remove this 78int pathbuf_maybe_copyin(const char *userpath, enum uio_seg seg, struct pathbuf **ret); 79 80/* 81 * Lookup parameters: this structure describes the subset of 82 * information from the nameidata structure that is passed 83 * through the VOP interface. 84 */ 85struct componentname { 86 /* 87 * Arguments to lookup. 88 */ 89 uint32_t cn_nameiop; /* namei operation */ 90 uint32_t cn_flags; /* flags to namei */ 91 kauth_cred_t cn_cred; /* credentials */ 92 /* 93 * Shared between lookup and commit routines. 94 */ 95 const char *cn_nameptr; /* pointer to looked up name */ 96 size_t cn_namelen; /* length of looked up comp */ 97}; 98 99/* 100 * Encapsulation of namei parameters. 101 */ 102struct nameidata { 103 /* 104 * Arguments to namei/lookup. 105 */ 106 struct vnode *ni_atdir; /* startup dir, cwd if null */ 107 struct pathbuf *ni_pathbuf; /* pathname container */ 108 char *ni_pnbuf; /* extra pathname buffer ref (XXX) */ 109 /* 110 * Arguments to lookup. 111 */ 112 struct vnode *ni_rootdir; /* logical root directory */ 113 struct vnode *ni_erootdir; /* emulation root directory */ 114 /* 115 * Results: returned from/manipulated by lookup 116 */ 117 struct vnode *ni_vp; /* vnode of result */ 118 struct vnode *ni_dvp; /* vnode of intermediate directory */ 119 /* 120 * Shared between namei and lookup/commit routines. 121 */ 122 size_t ni_pathlen; /* remaining chars in path */ 123 const char *ni_next; /* next location in pathname */ 124 unsigned int ni_loopcnt; /* count of symlinks encountered */ 125 /* 126 * Lookup parameters: this structure describes the subset of 127 * information from the nameidata structure that is passed 128 * through the VOP interface. 129 */ 130 struct componentname ni_cnd; 131}; 132 133/* 134 * namei operations 135 */ 136NAMEIFL LOOKUP 0 /* perform name lookup only */ 137NAMEIFL CREATE 1 /* setup for file creation */ 138NAMEIFL DELETE 2 /* setup for file deletion */ 139NAMEIFL RENAME 3 /* setup for file renaming */ 140NAMEIFL OPMASK 3 /* mask for operation */ 141/* 142 * namei operational modifier flags, stored in ni_cnd.cn_flags 143 */ 144NAMEIFL LOCKLEAF 0x00000004 /* lock inode on return */ 145NAMEIFL LOCKPARENT 0x00000008 /* want parent vnode returned locked */ 146NAMEIFL TRYEMULROOT 0x00000010 /* try relative to emulation root 147 first */ 148NAMEIFL NOCACHE 0x00000020 /* name must not be left in cache */ 149NAMEIFL FOLLOW 0x00000040 /* follow symbolic links */ 150NAMEIFL NOFOLLOW 0x00000000 /* do not follow symbolic links 151 (pseudo) */ 152NAMEIFL EMULROOTSET 0x00000080 /* emulation root already 153 in ni_erootdir */ 154NAMEIFL LOCKSHARED 0x00000100 /* want shared locks if possible */ 155NAMEIFL NOCHROOT 0x01000000 /* no chroot on abs path lookups */ 156NAMEIFL NONEXCLHACK 0x02000000 /* open wwith O_CREAT but not O_EXCL */ 157NAMEIFL MODMASK 0x030001fc /* mask of operational modifiers */ 158/* 159 * Namei parameter descriptors. 160 */ 161NAMEIFL NOCROSSMOUNT 0x0000800 /* do not cross mount points */ 162NAMEIFL RDONLY 0x0001000 /* lookup with read-only semantics */ 163NAMEIFL ISDOTDOT 0x0002000 /* current component name is .. */ 164NAMEIFL MAKEENTRY 0x0004000 /* entry is to be added to name cache */ 165NAMEIFL ISLASTCN 0x0008000 /* this is last component of pathname */ 166NAMEIFL WILLBEDIR 0x0010000 /* new files will be dirs */ 167NAMEIFL ISWHITEOUT 0x0020000 /* found whiteout */ 168NAMEIFL DOWHITEOUT 0x0040000 /* do whiteouts */ 169NAMEIFL REQUIREDIR 0x0080000 /* must be a directory */ 170NAMEIFL CREATEDIR 0x0200000 /* trailing slashes are ok */ 171NAMEIFL PARAMASK 0x02ff800 /* mask of parameter descriptors */ 172 173/* 174 * Initialization of a nameidata structure. 175 */ 176#define NDINIT(ndp, op, flags, pathbuf) { \ 177 (ndp)->ni_cnd.cn_nameiop = op; \ 178 (ndp)->ni_cnd.cn_flags = flags; \ 179 (ndp)->ni_atdir = NULL; \ 180 (ndp)->ni_pathbuf = pathbuf; \ 181 (ndp)->ni_cnd.cn_cred = kauth_cred_get(); \ 182} 183 184/* 185 * Use this to set the start directory for openat()-type operations. 186 */ 187#define NDAT(ndp, dir) { \ 188 (ndp)->ni_atdir = (dir); \ 189} 190 191#endif 192 193#ifdef __NAMECACHE_PRIVATE 194#include <sys/rbtree.h> 195 196/* 197 * For simplicity (and economy of storage), names longer than 198 * a maximum length of NCHNAMLEN are stored in non-pooled storage. 199 */ 200#define NCHNAMLEN sizeof(((struct namecache *)NULL)->nc_name) 201 202/* 203 * The uintptr_t-sized key value computed for each name consists of name 204 * length and a hash value. On 32-bit platforms the top NC_NLEN_BITS of 205 * the 32-bit hash value is lobbed off. 206 */ 207 208#define NC_NLEN_BITS 11 209#define NC_NLEN_MASK ((1 << NC_NLEN_BITS) - 1) 210#define NC_NLEN(ncp) ((ncp)->nc_key & NC_NLEN_MASK) 211 212/* 213 * Namecache entry. 214 * 215 * This structure describes the elements in the cache of recent names looked 216 * up by namei. It's carefully sized to take up 128 bytes on _LP64 and 64 217 * bytes on 32-bit machines, to make good use of space and the CPU caches. 218 * 219 * Items used during RB tree lookup (nc_tree, nc_key) are clustered at the 220 * start of the structure to minimise cache misses during lookup. 221 * 222 * Field markings and their corresponding locks: 223 * 224 * - stable throughout the lifetime of the namecache entry 225 * d protected by nc_dvp->vi_nc_lock 226 * v protected by nc_vp->vi_nc_listlock 227 * l protected by cache_lru_lock 228 */ 229struct namecache { 230 struct rb_node nc_tree; /* d red-black tree, must be first */ 231 uintptr_t nc_key; /* - hashed key value */ 232 TAILQ_ENTRY(namecache) nc_list; /* v nc_vp's list of cache entries */ 233 TAILQ_ENTRY(namecache) nc_lru; /* l pseudo-lru chain */ 234 struct vnode *nc_dvp; /* - vnode of parent of name */ 235 struct vnode *nc_vp; /* - vnode the name refers to */ 236 u_char nc_lrulist; /* l LRU list entry is on */ 237 u_char nc_whiteout; /* - whiteout indicator */ 238#ifdef _LP64 239 char nc_name[46]; /* - segment name */ 240#else 241 char nc_name[22]; /* - segment name */ 242#endif 243}; 244#endif /* __NAMECACHE_PRIVATE */ 245 246#ifdef _KERNEL 247#include <sys/kmem.h> 248 249struct mount; 250struct cpu_info; 251 252#define PNBUF_GET() ((char *)kmem_alloc(MAXPATHLEN, KM_SLEEP)) 253#define PNBUF_PUT(pnb) kmem_free((pnb), MAXPATHLEN) 254 255/* 256 * Typesafe flags for namei_simple/nameiat_simple. 257 * 258 * This encoding is not optimal but serves the important purpose of 259 * not being type-compatible with the regular namei flags. 260 */ 261struct namei_simple_flags_type; /* Opaque. */ 262typedef const struct namei_simple_flags_type *namei_simple_flags_t; /* Gross. */ 263extern const namei_simple_flags_t 264 NSM_NOFOLLOW_NOEMULROOT, 265 NSM_NOFOLLOW_TRYEMULROOT, 266 NSM_FOLLOW_NOEMULROOT, 267 NSM_FOLLOW_TRYEMULROOT; 268 269/* 270 * namei(at)?_simple_* - the simple cases of namei, with no struct 271 * nameidata involved. 272 * 273 * namei_simple_kernel takes a kernel-space path as the first argument. 274 * namei_simple_user takes a user-space path as the first argument. 275 * The nameiat_simple* variants handle relative path using the given 276 * directory vnode instead of current directory. 277 * 278 * A namei call can be converted to namei_simple_* if: 279 * - the second arg to NDINIT is LOOKUP; 280 * - it does not need the parent vnode, nd.ni_dvp; 281 * - the only flags it uses are (NO)FOLLOW and TRYEMULROOT; 282 * - it does not do anything else gross with the contents of nd. 283 */ 284int namei_simple_kernel(const char *, namei_simple_flags_t, struct vnode **); 285int namei_simple_user(const char *, namei_simple_flags_t, struct vnode **); 286int nameiat_simple(struct vnode *, struct pathbuf *, namei_simple_flags_t, 287 struct vnode **); 288int nameiat_simple_kernel(struct vnode *, const char *, namei_simple_flags_t, 289 struct vnode **); 290int nameiat_simple_user(struct vnode *, const char *, namei_simple_flags_t, 291 struct vnode **); 292 293int namei(struct nameidata *); 294uint32_t namei_hash(const char *, const char **); 295int lookup_for_nfsd(struct nameidata *, struct vnode *, int neverfollow); 296int lookup_for_nfsd_index(struct nameidata *, struct vnode *); 297int relookup(struct vnode *, struct vnode **, struct componentname *, int); 298void cache_purge1(struct vnode *, const char *, size_t, int); 299#define PURGE_PARENTS 1 300#define PURGE_CHILDREN 2 301#define cache_purge(vp) cache_purge1((vp),NULL,0,PURGE_PARENTS|PURGE_CHILDREN) 302bool cache_lookup(struct vnode *, const char *, size_t, uint32_t, uint32_t, 303 int *, struct vnode **); 304bool cache_lookup_raw(struct vnode *, const char *, size_t, uint32_t, 305 int *, struct vnode **); 306bool cache_lookup_linked(struct vnode *, const char *, size_t, 307 struct vnode **, krwlock_t **, kauth_cred_t); 308int cache_revlookup(struct vnode *, struct vnode **, char **, char *, 309 bool, accmode_t); 310int cache_diraccess(struct vnode *, int); 311void cache_enter(struct vnode *, struct vnode *, 312 const char *, size_t, uint32_t); 313void cache_enter_id(struct vnode *, mode_t, uid_t, gid_t, bool); 314bool cache_have_id(struct vnode *); 315void cache_vnode_init(struct vnode * ); 316void cache_vnode_fini(struct vnode * ); 317void cache_cpu_init(struct cpu_info *); 318void cache_enter_mount(struct vnode *, struct vnode *); 319bool cache_cross_mount(struct vnode **, krwlock_t **); 320bool cache_lookup_mount(struct vnode *, struct vnode **); 321 322void nchinit(void); 323void namecache_count_pass2(void); 324void namecache_count_2passes(void); 325void cache_purgevfs(struct mount *); 326void namecache_print(struct vnode *, void (*)(const char *, ...) 327 __printflike(1, 2)); 328 329#endif 330 331/* 332 * Stats on usefulness of namei caches. A couple of structures are 333 * used for counting, with members having the same names but different 334 * types. Containerize member names with the preprocessor to avoid 335 * cut-'n'-paste. 336 */ 337#define _NAMEI_CACHE_STATS(type) { \ 338 type ncs_goodhits; /* hits that we can really use */ \ 339 type ncs_neghits; /* negative hits that we can use */ \ 340 type ncs_badhits; /* hits we must drop */ \ 341 type ncs_falsehits; /* hits with id mismatch */ \ 342 type ncs_miss; /* misses */ \ 343 type ncs_long; /* long names that ignore cache */ \ 344 type ncs_pass2; /* names found with passes == 2 */ \ 345 type ncs_2passes; /* number of times we attempt it */ \ 346 type ncs_revhits; /* reverse-cache hits */ \ 347 type ncs_revmiss; /* reverse-cache misses */ \ 348 type ncs_denied; /* access denied */ \ 349} 350 351/* 352 * Sysctl deals with a uint64_t version of the stats and summary 353 * totals are kept that way. 354 */ 355struct nchstats _NAMEI_CACHE_STATS(uint64_t); 356 357/* #endif !_SYS_NAMEI_H_ (generated by gennameih.awk) */ 358