1/* $OpenBSD: namei.h,v 1.51 2026/03/08 16:41:19 deraadt Exp $ */
2/* $NetBSD: namei.h,v 1.11 1996/02/09 18:25:20 christos Exp $ */
3
4/*
5 * Copyright (c) 1985, 1989, 1991, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * @(#)namei.h 8.4 (Berkeley) 8/20/94
33 */
34
35#ifndef _SYS_NAMEI_H_
36#define _SYS_NAMEI_H_
37
38#include <sys/queue.h>
39#include <sys/tree.h>
40#include <sys/uio.h>
41
42struct unveil;
43
44/*
45 * Encapsulation of namei parameters.
46 */
47struct nameidata {
48 /*
49 * Arguments to namei/lookup.
50 */
51 const char *ni_dirp; /* pathname pointer */
52 int ni_dirfd; /* dirfd from *at() functions */
53 enum uio_seg ni_segflg; /* location of pathname */
54 /* u_long ni_nameiop; namei operation */
55 /* u_long ni_flags; flags to namei */
56 /* struct proc *ni_proc; process requesting lookup */
57 /*
58 * Arguments to lookup.
59 */
60 /* struct ucred *ni_cred; credentials */
61 struct vnode *ni_startdir; /* starting directory */
62 struct vnode *ni_rootdir; /* logical root directory */
63 uint64_t ni_pledge; /* expected pledge for namei */
64 u_char ni_unveil; /* required unveil flags for namei */
65 /*
66 * Results: returned from/manipulated by lookup
67 */
68 struct vnode *ni_vp; /* vnode of result */
69 struct vnode *ni_dvp; /* vnode of intermediate directory */
70
71 /*
72 * Shared between namei and lookup/commit routines.
73 */
74 size_t ni_pathlen; /* remaining chars in path */
75 char *ni_next; /* next location in pathname */
76 u_long ni_loopcnt; /* count of symlinks encountered */
77 struct unveil *ni_unveil_match; /* last matching unveil component */
78
79 /*
80 * Lookup parameters: this structure describes the subset of
81 * information from the nameidata structure that is passed
82 * through the VOP interface.
83 */
84 struct componentname {
85 /*
86 * Arguments to lookup.
87 */
88 u_long cn_nameiop; /* namei operation */
89 u_long cn_flags; /* flags to namei */
90 struct proc *cn_proc; /* process requesting lookup */
91 struct ucred *cn_cred; /* credentials */
92 /*
93 * Shared between lookup and commit routines.
94 */
95 char *cn_pnbuf; /* pathname buffer */
96 char *cn_rpbuf; /* realpath buffer */
97 size_t cn_rpi; /* realpath index */
98 char *cn_nameptr; /* pointer to looked up name */
99 long cn_namelen; /* length of looked up component */
100 long cn_consume; /* chars to consume in lookup() */
101 } ni_cnd;
102};
103
104#ifdef _KERNEL
105/*
106 * namei operations
107 */
108#define LOOKUP 0 /* perform name lookup only */
109#define CREATE 1 /* setup for file creation */
110#define DELETE 2 /* setup for file deletion */
111#define RENAME 3 /* setup for file renaming */
112#define OPMASK 3 /* mask for operation */
113/*
114 * namei operational modifier flags, stored in ni_cnd.flags
115 */
116#define LOCKLEAF 0x0004 /* lock inode on return */
117#define LOCKPARENT 0x0008 /* want parent vnode returned locked */
118#define WANTPARENT 0x0010 /* want parent vnode returned unlocked */
119#define NOCACHE 0x0020 /* name must not be left in cache */
120#define FOLLOW 0x0040 /* follow symbolic links */
121#define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
122#define MODMASK 0x00fc /* mask of operational modifiers */
123/*
124 * Namei parameter descriptors.
125 *
126 * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
127 * If the caller of namei sets the flag (for example execve wants to
128 * know the name of the program that is being executed), then it must
129 * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
130 * be freed by either the commit routine or the VOP_ABORT routine.
131 * SAVESTART is set only by the callers of namei. It implies SAVENAME
132 * plus the addition of saving the parent directory that contains the
133 * name in ni_startdir. It allows repeated calls to lookup for the
134 * name being sought. The caller is responsible for releasing the
135 * buffer and for vrele'ing ni_startdir.
136 */
137#define NOCROSSMOUNT 0x000100 /* do not cross mount points */
138#define RDONLY 0x000200 /* lookup with read-only semantics */
139#define HASBUF 0x000400 /* has allocated pathname buffer */
140#define SAVENAME 0x000800 /* save pathname buffer */
141#define SAVESTART 0x001000 /* save starting directory */
142#define ISDOTDOT 0x002000 /* current component name is .. */
143#define MAKEENTRY 0x004000 /* entry is to be added to name cache */
144#define ISLASTCN 0x008000 /* this is last component of pathname */
145#define ISSYMLINK 0x010000 /* symlink needs interpretation */
146#define REALPATH 0x020000 /* save pathname buffer for realpath */
147#define REQUIREDIR 0x080000 /* must be a directory */
148#define STRIPSLASHES 0x100000 /* strip trailing slashes */
149#define PDIRUNLOCK 0x200000 /* vfs_lookup() unlocked parent dir */
150#define BYPASSUNVEIL 0x400000 /* bypass pledgepath check */
151#define KERNELPATH 0x800000 /* access file as kernel, not process */
152
153/*
154 * Initialization of an nameidata structure.
155 */
156void ndinitat(struct nameidata *ndp, u_long op, u_long flags,
157 enum uio_seg segflg, int dirfd, const char *namep, struct proc *p);
158
159#define NDINITAT(ndp, op, flags, segflg, dirfd, namep, p) \
160 ndinitat(ndp, op, flags, segflg, dirfd, namep, p)
161
162#define NDINIT(ndp, op, flags, segflp, namep, p) \
163 ndinitat(ndp, op, flags, segflp, AT_FDCWD, namep, p)
164
165/* Defined for users of NDINIT(). */
166#define AT_FDCWD -100
167#endif
168
169/*
170 * This structure describes the elements in the cache of recent
171 * names looked up by namei.
172 */
173
174#define NAMECACHE_MAXLEN 31 /* maximum name segment length we bother with */
175
176struct namecache {
177 TAILQ_ENTRY(namecache) nc_lru; /* Regular Entry LRU chain */
178 TAILQ_ENTRY(namecache) nc_neg; /* Negative Entry LRU chain */
179 RBT_ENTRY(namecache) n_rbcache; /* Namecache rb tree from vnode */
180 TAILQ_ENTRY(namecache) nc_me; /* ncp's referring to me */
181 struct vnode *nc_dvp; /* vnode of parent of name */
182 u_long nc_dvpid; /* capability number of nc_dvp */
183 struct vnode *nc_vp; /* vnode the name refers to */
184 u_long nc_vpid; /* capability number of nc_vp */
185 char nc_nlen; /* length of name */
186 char nc_name[NAMECACHE_MAXLEN]; /* segment name */
187};
188
189#ifdef _KERNEL
190struct namecache_rb_cache;
191
192int namei(struct nameidata *ndp);
193int vfs_lookup(struct nameidata *ndp);
194int vfs_relookup(struct vnode *dvp, struct vnode **vpp,
195 struct componentname *cnp);
196void cache_tree_init(struct namecache_rb_cache *);
197void cache_purge(struct vnode *);
198int cache_lookup(struct vnode *, struct vnode **, struct componentname *);
199void cache_enter(struct vnode *, struct vnode *, struct componentname *);
200int cache_revlookup(struct vnode *, struct vnode **, char **, char *);
201void nchinit(void);
202struct mount;
203void cache_purgevfs(struct mount *);
204
205int unveil_add(struct proc *, struct nameidata *, const char *);
206void unveil_removevnode(struct vnode *);
207ssize_t unveil_find_cover(struct vnode *, struct proc *);
208struct unveil *unveil_lookup(struct vnode *, struct process *, ssize_t *);
209void unveil_start_relative(struct proc *, struct nameidata *, struct vnode *);
210void unveil_check_component(struct proc *, struct nameidata *, struct vnode *);
211int unveil_check_final(struct proc *, struct nameidata *);
212
213extern struct pool namei_pool;
214
215#endif
216
217/*
218 * Stats on usefulness of namei caches.
219 */
220struct nchstats {
221 u_int64_t ncs_goodhits; /* hits that we can really use */
222 u_int64_t ncs_neghits; /* negative hits that we can use */
223 u_int64_t ncs_badhits; /* hits we must drop */
224 u_int64_t ncs_falsehits; /* hits with id mismatch */
225 u_int64_t ncs_miss; /* misses */
226 u_int64_t ncs_long; /* long names that ignore cache */
227 u_int64_t ncs_pass2; /* names found with passes == 2 */
228 u_int64_t ncs_2passes; /* number of times we attempt it */
229 u_int64_t ncs_revhits; /* reverse-cache hits */
230 u_int64_t ncs_revmiss; /* reverse-cache misses */
231 u_int64_t ncs_dothits; /* hits on '.' lookups */
232 u_int64_t ncs_dotdothits; /* hits on '..' lookups */
233};
234
235/* These sysctl names are only really used by sysctl(8) */
236#define KERN_NCHSTATS_GOODHITS 1
237#define KERN_NCHSTATS_NEGHITS 2
238#define KERN_NCHSTATS_BADHITS 3
239#define KERN_NCHSTATS_FALSEHITS 4
240#define KERN_NCHSTATS_MISS 5
241#define KERN_NCHSTATS_LONG 6
242#define KERN_NCHSTATS_PASS2 7
243#define KERN_NCHSTATS_2PASSES 8
244#define KERN_NCHSTATS_REVHITS 9
245#define KERN_NCHSTATS_REVMISS 10
246#define KERN_NCHSTATS_DOTHITS 11
247#define KERN_NCHSTATS_DOTDOTHITS 12
248#define KERN_NCHSTATS_MAXID 13
249
250#define CTL_KERN_NCHSTATS_NAMES { \
251 { 0, 0 }, \
252 { "good_hits", CTLTYPE_QUAD }, \
253 { "negative_hits", CTLTYPE_QUAD }, \
254 { "bad_hits", CTLTYPE_QUAD }, \
255 { "false_hits", CTLTYPE_QUAD }, \
256 { "misses", CTLTYPE_QUAD }, \
257 { "long_names", CTLTYPE_QUAD }, \
258 { "pass2", CTLTYPE_QUAD }, \
259 { "2passes", CTLTYPE_QUAD }, \
260 { "ncs_revhits", CTLTYPE_QUAD }, \
261 { "ncs_revmiss", CTLTYPE_QUAD }, \
262 { "ncs_dothits", CTLTYPE_QUAD }, \
263 { "nch_dotdothits", CTLTYPE_QUAD }, \
264}
265
266/* Unveil flags for namei */
267#define UNVEIL_READ 0x01
268#define UNVEIL_WRITE 0x02
269#define UNVEIL_CREATE 0x04
270#define UNVEIL_EXEC 0x08
271#define UNVEIL_USERSET 0x10
272#define UNVEIL_PLEDGEOPEN 0X20
273#define UNVEIL_MASK 0x0f
274
275#endif /* !_SYS_NAMEI_H_ */