1 /* $OpenBSD: namei.h,v 1.20 2007/08/07 07:41:59 thib 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
40 /*
41 * Encapsulation of namei parameters.
42 */
43 struct nameidata {
44 /*
45 * Arguments to namei/lookup.
46 */
47 const char *ni_dirp; /* pathname pointer */
48 enum uio_seg ni_segflg; /* location of pathname */
49 /* u_long ni_nameiop; namei operation */
50 /* u_long ni_flags; flags to namei */
51 /* struct proc *ni_proc; process requesting lookup */
52 /*
53 * Arguments to lookup.
54 */
55 /* struct ucred *ni_cred; credentials */
56 struct vnode *ni_startdir; /* starting directory */
57 struct vnode *ni_rootdir; /* logical 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 char *ni_next; /* next location in pathname */
68 u_long 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 u_long cn_nameiop; /* namei operation */
79 u_long cn_flags; /* flags to namei */
80 struct proc *cn_proc; /* process requesting lookup */
81 struct ucred *cn_cred; /* credentials */
82 /*
83 * Shared between lookup and commit routines.
84 */
85 char *cn_pnbuf; /* pathname buffer */
86 char *cn_nameptr; /* pointer to looked up name */
87 long cn_namelen; /* length of looked up component */
88 u_int32_t cn_hash; /* hash value of looked up name */
89 long cn_consume; /* chars to consume in lookup() */
90 } ni_cnd;
91 };
92
93 #ifdef _KERNEL
94 /*
95 * namei operations
96 */
97 #define LOOKUP 0 /* perform name lookup only */
98 #define CREATE 1 /* setup for file creation */
99 #define DELETE 2 /* setup for file deletion */
100 #define RENAME 3 /* setup for file renaming */
101 #define OPMASK 3 /* mask for operation */
102 /*
103 * namei operational modifier flags, stored in ni_cnd.flags
104 */
105 #define LOCKLEAF 0x0004 /* lock inode on return */
106 #define LOCKPARENT 0x0008 /* want parent vnode returned locked */
107 #define WANTPARENT 0x0010 /* want parent vnode returned unlocked */
108 #define NOCACHE 0x0020 /* name must not be left in cache */
109 #define FOLLOW 0x0040 /* follow symbolic links */
110 #define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
111 #define 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 #define NOCROSSMOUNT 0x000100 /* do not cross mount points */
127 #define RDONLY 0x000200 /* lookup with read-only semantics */
128 #define HASBUF 0x000400 /* has allocated pathname buffer */
129 #define SAVENAME 0x000800 /* save pathanme buffer */
130 #define SAVESTART 0x001000 /* save starting directory */
131 #define ISDOTDOT 0x002000 /* current component name is .. */
132 #define MAKEENTRY 0x004000 /* entry is to be added to name cache */
133 #define ISLASTCN 0x008000 /* this is last component of pathname */
134 #define ISSYMLINK 0x010000 /* symlink needs interpretation */
135 #define REQUIREDIR 0x080000 /* must be a directory */
136 #define STRIPSLASHES 0x100000 /* strip trailing slashes */
137 #define PDIRUNLOCK 0x200000 /* vfs_lookup() unlocked parent dir */
138
139 /*
140 * Initialization of an nameidata structure.
141 */
142 #define NDINIT(ndp, op, flags, segflg, namep, p) { \
143 (ndp)->ni_cnd.cn_nameiop = op; \
144 (ndp)->ni_cnd.cn_flags = flags; \
145 (ndp)->ni_segflg = segflg; \
146 (ndp)->ni_dirp = namep; \
147 (ndp)->ni_cnd.cn_proc = p; \
148 }
149 #endif
150
151 /*
152 * This structure describes the elements in the cache of recent
153 * names looked up by namei. NCHNAMLEN is sized to make structure
154 * size a power of two to optimize malloc's. Minimum reasonable
155 * size is 15.
156 */
157
158 #define NCHNAMLEN 31 /* maximum name segment length we bother with */
159
160 struct namecache {
161 LIST_ENTRY(namecache) nc_hash; /* hash chain */
162 LIST_ENTRY(namecache) nc_vhash; /* (reverse) directory hash chain */
163 TAILQ_ENTRY(namecache) nc_lru; /* LRU chain */
164 struct vnode *nc_dvp; /* vnode of parent of name */
165 u_long nc_dvpid; /* capability number of nc_dvp */
166 struct vnode *nc_vp; /* vnode the name refers to */
167 u_long nc_vpid; /* capability number of nc_vp */
168 char nc_nlen; /* length of name */
169 char nc_name[NCHNAMLEN]; /* segment name */
170 };
171
172 #ifdef _KERNEL
173 int namei(struct nameidata *ndp);
174 int lookup(struct nameidata *ndp);
175 int relookup(struct vnode *dvp, struct vnode **vpp,
176 struct componentname *cnp);
177 void cache_purge(struct vnode *);
178 int cache_lookup(struct vnode *, struct vnode **, struct componentname *);
179 void cache_enter(struct vnode *, struct vnode *, struct componentname *);
180 int cache_revlookup(struct vnode *, struct vnode **, char **, char *);
181 void nchinit(void);
182 struct mount;
183 void cache_purgevfs(struct mount *);
184
185 extern struct pool namei_pool;
186
187 #endif
188
189 /*
190 * Stats on usefulness of namei caches.
191 */
192 struct nchstats {
193 long ncs_goodhits; /* hits that we can really use */
194 long ncs_neghits; /* negative hits that we can use */
195 long ncs_badhits; /* hits we must drop */
196 long ncs_falsehits; /* hits with id mismatch */
197 long ncs_miss; /* misses */
198 long ncs_long; /* long names that ignore cache */
199 long ncs_pass2; /* names found with passes == 2 */
200 long ncs_2passes; /* number of times we attempt it */
201 long ncs_revhits; /* reverse-cache hits */
202 long ncs_revmiss; /* reverse-cache misses */
203 };
204
205 /* These sysctl names are only really used by sysctl(8) */
206 #define KERN_NCHSTATS_GOODHITS 1
207 #define KERN_NCHSTATS_NEGHITS 2
208 #define KERN_NCHSTATS_BADHITS 3
209 #define KERN_NCHSTATS_FALSEHITS 4
210 #define KERN_NCHSTATS_MISS 5
211 #define KERN_NCHSTATS_LONG 6
212 #define KERN_NCHSTATS_PASS2 7
213 #define KERN_NCHSTATS_2PASSES 8
214 #define KERN_NCHSTATS_REVHITS 9
215 #define KERN_NCHSTATS_REVMISS 10
216 #define KERN_NCHSTATS_MAXID 11
217
218 #define CTL_KERN_NCHSTATS_NAMES { \
219 { 0, 0 }, \
220 { "good_hits", CTLTYPE_INT }, \
221 { "negative_hits", CTLTYPE_INT }, \
222 { "bad_hits", CTLTYPE_INT }, \
223 { "false_hits", CTLTYPE_INT }, \
224 { "misses", CTLTYPE_INT }, \
225 { "long_names", CTLTYPE_INT }, \
226 { "pass2", CTLTYPE_INT }, \
227 { "2passes", CTLTYPE_INT }, \
228 { "ncs_revhits", CTLTYPE_INT }, \
229 { "ncs_revmiss", CTLTYPE_INT }, \
230 }
231 #endif /* !_SYS_NAMEI_H_ */