FreeBSD/Linux Kernel Cross Reference
sys/sys/namei.h
1 /* $NetBSD: namei.h,v 1.34.2.1 2004/07/10 14:23:00 tron 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
39 /*
40 * Encapsulation of namei parameters.
41 */
42 struct nameidata {
43 /*
44 * Arguments to namei/lookup.
45 */
46 const char *ni_dirp; /* pathname pointer */
47 enum uio_seg ni_segflg; /* location of pathname */
48 /* u_long ni_nameiop; namei operation */
49 /* u_long ni_flags; flags to namei */
50 /* struct proc *ni_proc; process requesting lookup */
51 /*
52 * Arguments to lookup.
53 */
54 /* struct ucred *ni_cred; credentials */
55 struct vnode *ni_startdir; /* starting directory */
56 struct vnode *ni_rootdir; /* logical root directory */
57 /*
58 * Results: returned from/manipulated by lookup
59 */
60 struct vnode *ni_vp; /* vnode of result */
61 struct vnode *ni_dvp; /* vnode of intermediate directory */
62 /*
63 * Shared between namei and lookup/commit routines.
64 */
65 size_t ni_pathlen; /* remaining chars in path */
66 const char *ni_next; /* next location in pathname */
67 u_long ni_loopcnt; /* count of symlinks encountered */
68 /*
69 * Lookup parameters: this structure describes the subset of
70 * information from the nameidata structure that is passed
71 * through the VOP interface.
72 */
73 struct componentname {
74 /*
75 * Arguments to lookup.
76 */
77 u_long cn_nameiop; /* namei operation */
78 u_long cn_flags; /* flags to namei */
79 struct proc *cn_proc; /* process requesting lookup */
80 struct ucred *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 long cn_namelen; /* length of looked up component */
87 u_long cn_hash; /* hash value of looked up name */
88 long cn_consume; /* chars to consume in lookup() */
89 } ni_cnd;
90 };
91
92 #ifdef _KERNEL
93 /*
94 * namei operations
95 */
96 #define LOOKUP 0 /* perform name lookup only */
97 #define CREATE 1 /* setup for file creation */
98 #define DELETE 2 /* setup for file deletion */
99 #define RENAME 3 /* setup for file renaming */
100 #define OPMASK 3 /* mask for operation */
101 /*
102 * namei operational modifier flags, stored in ni_cnd.cn_flags
103 */
104 #define LOCKLEAF 0x0004 /* lock inode on return */
105 #define LOCKPARENT 0x0008 /* want parent vnode returned locked */
106 #define WANTPARENT 0x0010 /* want parent vnode returned unlocked */
107 #define NOCACHE 0x0020 /* name must not be left in cache */
108 #define FOLLOW 0x0040 /* follow symbolic links */
109 #define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
110 #define MODMASK 0x00fc /* mask of operational modifiers */
111 /*
112 * Namei parameter descriptors.
113 *
114 * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
115 * If the caller of namei sets the flag (for example execve wants to
116 * know the name of the program that is being executed), then it must
117 * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
118 * be freed by either the commit routine or the VOP_ABORT routine.
119 * SAVESTART is set only by the callers of namei. It implies SAVENAME
120 * plus the addition of saving the parent directory that contains the
121 * name in ni_startdir. It allows repeated calls to lookup for the
122 * name being sought. The caller is responsible for releasing the
123 * buffer and for vrele'ing ni_startdir.
124 */
125 #define NOCROSSMOUNT 0x0000100 /* do not cross mount points */
126 #define RDONLY 0x0000200 /* lookup with read-only semantics */
127 #define HASBUF 0x0000400 /* has allocated pathname buffer */
128 #define SAVENAME 0x0000800 /* save pathname buffer */
129 #define SAVESTART 0x0001000 /* save starting directory */
130 #define ISDOTDOT 0x0002000 /* current component name is .. */
131 #define MAKEENTRY 0x0004000 /* entry is to be added to name cache */
132 #define ISLASTCN 0x0008000 /* this is last component of pathname */
133 #define ISSYMLINK 0x0010000 /* symlink needs interpretation */
134 #define ISWHITEOUT 0x0020000 /* found whiteout */
135 #define DOWHITEOUT 0x0040000 /* do whiteouts */
136 #define REQUIREDIR 0x0080000 /* must be a directory */
137 #define PDIRUNLOCK 0x0100000 /* vfs_lookup() unlocked parent dir */
138 #define CREATEDIR 0x0200000 /* creating entry is a directory */
139 #define PARAMASK 0x03fff00 /* mask of parameter descriptors */
140 /*
141 * Initialization of an nameidata structure.
142 */
143 #define NDINIT(ndp, op, flags, segflg, namep, p) { \
144 (ndp)->ni_cnd.cn_nameiop = op; \
145 (ndp)->ni_cnd.cn_flags = flags; \
146 (ndp)->ni_segflg = segflg; \
147 (ndp)->ni_dirp = namep; \
148 (ndp)->ni_cnd.cn_proc = p; \
149 (ndp)->ni_cnd.cn_cred = p->p_ucred; \
150 }
151 #endif
152
153 /*
154 * This structure describes the elements in the cache of recent
155 * names looked up by namei. NCHNAMLEN is sized to make structure
156 * size a power of two to optimize malloc's. Minimum reasonable
157 * size is 15.
158 */
159
160 #define NCHNAMLEN 31 /* maximum name segment length we bother with */
161
162 struct namecache {
163 LIST_ENTRY(namecache) nc_hash; /* hash chain */
164 TAILQ_ENTRY(namecache) nc_lru; /* LRU chain */
165 LIST_ENTRY(namecache) nc_vhash; /* directory hash chain */
166 LIST_ENTRY(namecache) nc_dvlist;
167 struct vnode *nc_dvp; /* vnode of parent of name */
168 LIST_ENTRY(namecache) nc_vlist;
169 struct vnode *nc_vp; /* vnode the name refers to */
170 int nc_flags; /* copy of componentname's ISWHITEOUT */
171 char nc_nlen; /* length of name */
172 char nc_name[NCHNAMLEN]; /* segment name */
173 };
174
175 #ifdef _KERNEL
176 #include <sys/mallocvar.h>
177 #include <sys/pool.h>
178
179 extern struct pool pnbuf_pool; /* pathname buffer pool */
180 extern struct pool_cache pnbuf_cache; /* pathname buffer cache */
181
182 MALLOC_DECLARE(M_NAMEI);
183
184 #define PNBUF_GET() pool_cache_get(&pnbuf_cache, PR_WAITOK)
185 #define PNBUF_PUT(pnb) pool_cache_put(&pnbuf_cache, (pnb))
186
187 int namei __P((struct nameidata *));
188 uint32_t namei_hash __P((const char *, const char **));
189 int lookup __P((struct nameidata *));
190 int relookup __P((struct vnode *, struct vnode **, struct componentname *));
191 void cache_purge __P((struct vnode *));
192 void cache_purge1 __P((struct vnode *, const struct componentname *, int));
193 #define PURGE_PARENTS 1
194 #define PURGE_CHILDREN 2
195 #define cache_purge(vp) cache_purge1((vp), NULL, PURGE_PARENTS|PURGE_CHILDREN)
196 int cache_lookup __P((struct vnode *, struct vnode **, struct componentname *));
197 int cache_revlookup __P((struct vnode *, struct vnode **, char **, char *));
198 void cache_enter __P((struct vnode *, struct vnode *, struct componentname *));
199 void nchinit __P((void));
200 void nchreinit __P((void));
201 struct mount;
202 void cache_purgevfs __P((struct mount *));
203 void namecache_print(struct vnode *, void (*)(const char *, ...));
204 #endif
205
206 /*
207 * Stats on usefulness of namei caches.
208 */
209 struct nchstats {
210 long ncs_goodhits; /* hits that we can really use */
211 long ncs_neghits; /* negative hits that we can use */
212 long ncs_badhits; /* hits we must drop */
213 long ncs_falsehits; /* hits with id mismatch */
214 long ncs_miss; /* misses */
215 long ncs_long; /* long names that ignore cache */
216 long ncs_pass2; /* names found with passes == 2 */
217 long ncs_2passes; /* number of times we attempt it */
218 long ncs_revhits; /* reverse-cache hits */
219 long ncs_revmiss; /* reverse-cache misses */
220 };
221
222 #ifdef _KERNEL
223 extern struct nchstats nchstats;
224 #endif
225 #endif /* !_SYS_NAMEI_H_ */
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