FreeBSD/Linux Kernel Cross Reference
sys/sys/namei.src
1 /* $NetBSD: namei.src,v 1.8.14.2 2010/02/14 13:27:45 bouyer 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 * Encapsulation of namei parameters.
45 */
46 struct nameidata {
47 /*
48 * Arguments to namei/lookup.
49 */
50 const char *ni_dirp; /* pathname pointer */
51 enum uio_seg ni_segflg; /* location of pathname */
52 /*
53 * Arguments to lookup.
54 */
55 struct vnode *ni_startdir; /* starting directory */
56 struct vnode *ni_rootdir; /* logical root directory */
57 struct vnode *ni_erootdir; /* emulation root directory */
58 /*
59 * Results: returned from/manipulated by lookup
60 */
61 struct vnode *ni_vp; /* vnode of result */
62 struct vnode *ni_dvp; /* vnode of intermediate directory */
63 /*
64 * Shared between namei and lookup/commit routines.
65 */
66 size_t ni_pathlen; /* remaining chars in path */
67 const char *ni_next; /* next location in pathname */
68 unsigned int ni_loopcnt; /* count of symlinks encountered */
69 /*
70 * Lookup parameters: this structure describes the subset of
71 * information from the nameidata structure that is passed
72 * through the VOP interface.
73 */
74 struct componentname {
75 /*
76 * Arguments to lookup.
77 */
78 uint32_t cn_nameiop; /* namei operation */
79 uint32_t cn_flags; /* flags to namei */
80 kauth_cred_t cn_cred; /* credentials */
81 /*
82 * Shared between lookup and commit routines.
83 */
84 char *cn_pnbuf; /* pathname buffer */
85 const char *cn_nameptr; /* pointer to looked up name */
86 size_t cn_namelen; /* length of looked up comp */
87 u_long cn_hash; /* hash val of looked up name */
88 size_t cn_consume; /* chars to consume in lookup */
89 } ni_cnd;
90 };
91
92 /*
93 * namei operations
94 */
95 NAMEIFL LOOKUP 0 /* perform name lookup only */
96 NAMEIFL CREATE 1 /* setup for file creation */
97 NAMEIFL DELETE 2 /* setup for file deletion */
98 NAMEIFL RENAME 3 /* setup for file renaming */
99 NAMEIFL OPMASK 3 /* mask for operation */
100 /*
101 * namei operational modifier flags, stored in ni_cnd.cn_flags
102 */
103 NAMEIFL LOCKLEAF 0x0004 /* lock inode on return */
104 NAMEIFL LOCKPARENT 0x0008 /* want parent vnode returned locked */
105 NAMEIFL NOCHROOT 0x0010 /* no chroot on abs path lookups */
106 NAMEIFL NOCACHE 0x0020 /* name must not be left in cache */
107 NAMEIFL FOLLOW 0x0040 /* follow symbolic links */
108 NAMEIFL NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
109 NAMEIFL TRYEMULROOT 0x0010 /* try relative to emulation root first */
110 NAMEIFL EMULROOTSET 0x0080 /* emulation root already in ni_erootdir */
111 NAMEIFL MODMASK 0x00fc /* mask of operational modifiers */
112 /*
113 * Namei parameter descriptors.
114 *
115 * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
116 * If the caller of namei sets the flag (for example execve wants to
117 * know the name of the program that is being executed), then it must
118 * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
119 * be freed by either the commit routine or the VOP_ABORT routine.
120 * SAVESTART is set only by the callers of namei. It implies SAVENAME
121 * plus the addition of saving the parent directory that contains the
122 * name in ni_startdir. It allows repeated calls to lookup for the
123 * name being sought. The caller is responsible for releasing the
124 * buffer and for vrele'ing ni_startdir.
125 */
126 NAMEIFL NOCROSSMOUNT 0x0000100 /* do not cross mount points */
127 NAMEIFL RDONLY 0x0000200 /* lookup with read-only semantics */
128 NAMEIFL HASBUF 0x0000400 /* has allocated pathname buffer */
129 NAMEIFL SAVENAME 0x0000800 /* save pathname buffer */
130 NAMEIFL SAVESTART 0x0001000 /* save starting directory */
131 NAMEIFL ISDOTDOT 0x0002000 /* current component name is .. */
132 NAMEIFL MAKEENTRY 0x0004000 /* entry is to be added to name cache */
133 NAMEIFL ISLASTCN 0x0008000 /* this is last component of pathname */
134 NAMEIFL ISSYMLINK 0x0010000 /* symlink needs interpretation */
135 NAMEIFL ISWHITEOUT 0x0020000 /* found whiteout */
136 NAMEIFL DOWHITEOUT 0x0040000 /* do whiteouts */
137 NAMEIFL REQUIREDIR 0x0080000 /* must be a directory */
138 NAMEIFL CREATEDIR 0x0200000 /* trailing slashes are ok */
139 NAMEIFL INRENAME 0x0400000 /* operation is a part of ``rename'' */
140 NAMEIFL PARAMASK 0x06fff00 /* mask of parameter descriptors */
141
142 /*
143 * Initialization of an nameidata structure.
144 */
145 #define NDINIT(ndp, op, flags, segflg, namep) { \
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_cred = kauth_cred_get(); \
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 #define NCHNAMLEN 31 /* maximum name segment length we bother with */
162
163 /*
164 * Namecache entry. This structure is arranged so that frequently
165 * accessed and mostly read-only data is toward the front, with
166 * infrequently accessed data and the lock towards the rear. The
167 * lock is then more likely to be in a seperate cache line.
168 */
169 struct namecache {
170 LIST_ENTRY(namecache) nc_hash; /* hash chain */
171 LIST_ENTRY(namecache) nc_vhash; /* directory hash chain */
172 struct vnode *nc_dvp; /* vnode of parent of name */
173 struct vnode *nc_vp; /* vnode the name refers to */
174 int nc_flags; /* copy of componentname's ISWHITEOUT */
175 char nc_nlen; /* length of name */
176 char nc_name[NCHNAMLEN]; /* segment name */
177 void *nc_gcqueue; /* queue for garbage collection */
178 TAILQ_ENTRY(namecache) nc_lru; /* psuedo-lru chain */
179 LIST_ENTRY(namecache) nc_dvlist;
180 LIST_ENTRY(namecache) nc_vlist;
181 kmutex_t nc_lock; /* lock on this entry */
182 int nc_hittime; /* last time scored a hit */
183 };
184
185 #ifdef _KERNEL
186 #include <sys/mallocvar.h>
187 #include <sys/pool.h>
188
189 struct mount;
190 struct cpu_info;
191
192 extern pool_cache_t pnbuf_cache; /* pathname buffer cache */
193
194 #define PNBUF_GET() pool_cache_get(pnbuf_cache, PR_WAITOK)
195 #define PNBUF_PUT(pnb) pool_cache_put(pnbuf_cache, (pnb))
196
197 int namei(struct nameidata *);
198 uint32_t namei_hash(const char *, const char **);
199 int lookup(struct nameidata *);
200 int relookup(struct vnode *, struct vnode **, struct componentname *);
201 void cache_purge1(struct vnode *, const struct componentname *, int);
202 #define PURGE_PARENTS 1
203 #define PURGE_CHILDREN 2
204 #define cache_purge(vp) cache_purge1((vp), NULL, PURGE_PARENTS|PURGE_CHILDREN)
205 int cache_lookup(struct vnode *, struct vnode **, struct componentname *);
206 int cache_lookup_raw(struct vnode *, struct vnode **,
207 struct componentname *);
208 int cache_revlookup(struct vnode *, struct vnode **, char **, char *);
209 void cache_enter(struct vnode *, struct vnode *, struct componentname *);
210 void nchinit(void);
211 void nchreinit(void);
212 void cache_cpu_init(struct cpu_info *);
213 void cache_purgevfs(struct mount *);
214 void namecache_print(struct vnode *, void (*)(const char *, ...));
215
216 #endif
217
218 /*
219 * Stats on usefulness of namei caches.
220 * XXX: should be 64-bit counters.
221 */
222 struct nchstats {
223 long ncs_goodhits; /* hits that we can really use */
224 long ncs_neghits; /* negative hits that we can use */
225 long ncs_badhits; /* hits we must drop */
226 long ncs_falsehits; /* hits with id mismatch */
227 long ncs_miss; /* misses */
228 long ncs_long; /* long names that ignore cache */
229 long ncs_pass2; /* names found with passes == 2 */
230 long ncs_2passes; /* number of times we attempt it */
231 long ncs_revhits; /* reverse-cache hits */
232 long ncs_revmiss; /* reverse-cache misses */
233 };
234
235 #ifdef _KERNEL
236 extern struct nchstats nchstats;
237 #endif
238 /* #endif !_SYS_NAMEI_H_ (generated by gennameih.awk) */
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