FreeBSD/Linux Kernel Cross Reference
sys/sys/namei.h
1 /*
2 * Copyright (c) 1985, 1989, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)namei.h 8.5 (Berkeley) 1/9/95
34 * $FreeBSD: src/sys/sys/namei.h,v 1.11.2.1 1999/09/05 08:22:42 peter Exp $
35 */
36
37 #ifndef _SYS_NAMEI_H_
38 #define _SYS_NAMEI_H_
39
40 #include <sys/queue.h>
41
42 /*
43 * Encapsulation of namei parameters.
44 */
45 struct nameidata {
46 /*
47 * Arguments to namei/lookup.
48 */
49 const char *ni_dirp; /* pathname pointer */
50 enum uio_seg ni_segflg; /* location of pathname */
51 /* u_long ni_nameiop; namei operation */
52 /* u_long ni_flags; flags to namei */
53 /* struct proc *ni_proc; process requesting lookup */
54 /*
55 * Arguments to lookup.
56 */
57 /* struct ucred *ni_cred; credentials */
58 struct vnode *ni_startdir; /* starting directory */
59 struct vnode *ni_rootdir; /* logical root directory */
60 /*
61 * Results: returned from/manipulated by lookup
62 */
63 struct vnode *ni_vp; /* vnode of result */
64 struct vnode *ni_dvp; /* vnode of intermediate directory */
65 /*
66 * Shared between namei and lookup/commit routines.
67 */
68 long ni_pathlen; /* remaining chars in path */
69 char *ni_next; /* next location in pathname */
70 u_long ni_loopcnt; /* count of symlinks encountered */
71 /*
72 * Lookup parameters: this structure describes the subset of
73 * information from the nameidata structure that is passed
74 * through the VOP interface.
75 */
76 struct componentname {
77 /*
78 * Arguments to lookup.
79 */
80 u_long cn_nameiop; /* namei operation */
81 u_long cn_flags; /* flags to namei */
82 struct proc *cn_proc; /* process requesting lookup */
83 struct ucred *cn_cred; /* credentials */
84 /*
85 * Shared between lookup and commit routines.
86 */
87 char *cn_pnbuf; /* pathname buffer */
88 char *cn_nameptr; /* pointer to looked up name */
89 long cn_namelen; /* length of looked up component */
90 u_long cn_hash; /* hash value of looked up name */
91 long cn_consume; /* chars to consume in lookup() */
92 } ni_cnd;
93 };
94
95 #ifdef KERNEL
96 /*
97 * namei operations
98 */
99 #define LOOKUP 0 /* perform name lookup only */
100 #define CREATE 1 /* setup for file creation */
101 #define DELETE 2 /* setup for file deletion */
102 #define RENAME 3 /* setup for file renaming */
103 #define OPMASK 3 /* mask for operation */
104 /*
105 * namei operational modifier flags, stored in ni_cnd.flags
106 */
107 #define LOCKLEAF 0x0004 /* lock inode on return */
108 #define LOCKPARENT 0x0008 /* want parent vnode returned locked */
109 #define WANTPARENT 0x0010 /* want parent vnode returned unlocked */
110 #define NOCACHE 0x0020 /* name must not be left in cache */
111 #define FOLLOW 0x0040 /* follow symbolic links */
112 #define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
113 #define MODMASK 0x00fc /* mask of operational modifiers */
114 /*
115 * Namei parameter descriptors.
116 *
117 * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
118 * If the caller of namei sets the flag (for example execve wants to
119 * know the name of the program that is being executed), then it must
120 * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
121 * be freed by either the commit routine or the VOP_ABORT routine.
122 * SAVESTART is set only by the callers of namei. It implies SAVENAME
123 * plus the addition of saving the parent directory that contains the
124 * name in ni_startdir. It allows repeated calls to lookup for the
125 * name being sought. The caller is responsible for releasing the
126 * buffer and for vrele'ing ni_startdir.
127 */
128 #define NOCROSSMOUNT 0x000100 /* do not cross mount points */
129 #define RDONLY 0x000200 /* lookup with read-only semantics */
130 #define HASBUF 0x000400 /* has allocated pathname buffer */
131 #define SAVENAME 0x000800 /* save pathname buffer */
132 #define SAVESTART 0x001000 /* save starting directory */
133 #define ISDOTDOT 0x002000 /* current component name is .. */
134 #define MAKEENTRY 0x004000 /* entry is to be added to name cache */
135 #define ISLASTCN 0x008000 /* this is last component of pathname */
136 #define ISSYMLINK 0x010000 /* symlink needs interpretation */
137 #define ISWHITEOUT 0x020000 /* found whiteout */
138 #define DOWHITEOUT 0x040000 /* do whiteouts */
139 #define WILLBEDIR 0x080000 /* new files will be dirs; allow trailing / */
140 #define ISUNICODE 0x100000 /* current component name is unicode*/
141 #define PARAMASK 0x1fff00 /* mask of parameter descriptors */
142 /*
143 * Initialization of an nameidata structure.
144 */
145 #define NDINIT(ndp, op, flags, segflg, namep, p) { \
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_proc = p; \
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 #ifdef NCH_STATISTICS
162 #define NCHNAMLEN 23 /* maximum name segment length we bother with */
163 #else
164 #define NCHNAMLEN 31 /* maximum name segment length we bother with */
165 #endif
166
167 struct namecache {
168 LIST_ENTRY(namecache) nc_hash; /* hash chain */
169 TAILQ_ENTRY(namecache) nc_lru; /* LRU chain */
170 struct vnode *nc_dvp; /* vnode of parent of name */
171 u_long nc_dvpid; /* capability number of nc_dvp */
172 struct vnode *nc_vp; /* vnode the name refers to */
173 u_long nc_vpid; /* capability number of nc_vp */
174 #ifdef NCH_STATISTICS
175 u_long nc_nbr; /* a serial number */
176 u_long nc_hits; /* how many times we got hit */
177 #endif
178 char nc_nlen; /* length of name */
179 char nc_name[NCHNAMLEN]; /* segment name */
180 };
181
182 #ifdef KERNEL
183 extern u_long nextvnodeid;
184 extern u_long numcache;
185 extern u_long numvnodes;
186
187 int namei __P((struct nameidata *ndp));
188 int lookup __P((struct nameidata *ndp));
189 int relookup __P((struct vnode *dvp, struct vnode **vpp,
190 struct componentname *cnp));
191 #endif
192
193 /*
194 * Stats on usefulness of namei caches.
195 */
196 struct nchstats {
197 long ncs_goodhits; /* hits that we can really use */
198 long ncs_neghits; /* negative hits that we can use */
199 long ncs_badhits; /* hits we must drop */
200 long ncs_falsehits; /* hits with id mismatch */
201 long ncs_miss; /* misses */
202 long ncs_long; /* long names that ignore cache */
203 long ncs_pass2; /* names found with passes == 2 */
204 long ncs_2passes; /* number of times we attempt it */
205 };
206
207 extern struct nchstats nchstats;
208
209 #endif /* !_SYS_NAMEI_H_ */
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