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: releng/5.2/sys/sys/namei.h 118607 2003-08-07 15:04:27Z jhb $
35 */
36
37 #ifndef _SYS_NAMEI_H_
38 #define _SYS_NAMEI_H_
39
40 #include <sys/queue.h>
41 #include <sys/uio.h>
42
43 struct componentname {
44 /*
45 * Arguments to lookup.
46 */
47 u_long cn_nameiop; /* namei operation */
48 u_long cn_flags; /* flags to namei */
49 struct thread *cn_thread;/* thread requesting lookup */
50 struct ucred *cn_cred; /* credentials */
51 /*
52 * Shared between lookup and commit routines.
53 */
54 char *cn_pnbuf; /* pathname buffer */
55 char *cn_nameptr; /* pointer to looked up name */
56 long cn_namelen; /* length of looked up component */
57 long cn_consume; /* chars to consume in lookup() */
58 };
59
60 /*
61 * Encapsulation of namei parameters.
62 */
63 struct nameidata {
64 /*
65 * Arguments to namei/lookup.
66 */
67 const char *ni_dirp; /* pathname pointer */
68 enum uio_seg ni_segflg; /* location of pathname */
69 /*
70 * Arguments to lookup.
71 */
72 struct vnode *ni_startdir; /* starting directory */
73 struct vnode *ni_rootdir; /* logical root directory */
74 struct vnode *ni_topdir; /* logical top directory */
75 /*
76 * Results: returned from/manipulated by lookup
77 */
78 struct vnode *ni_vp; /* vnode of result */
79 struct vnode *ni_dvp; /* vnode of intermediate directory */
80 /*
81 * Shared between namei and lookup/commit routines.
82 */
83 size_t ni_pathlen; /* remaining chars in path */
84 char *ni_next; /* next location in pathname */
85 u_long ni_loopcnt; /* count of symlinks encountered */
86 /*
87 * Lookup parameters: this structure describes the subset of
88 * information from the nameidata structure that is passed
89 * through the VOP interface.
90 */
91 struct componentname ni_cnd;
92 };
93
94 #ifdef _KERNEL
95 /*
96 * namei operations
97 */
98 #define LOOKUP 0 /* perform name lookup only */
99 #define CREATE 1 /* setup for file creation */
100 #define DELETE 2 /* setup for file deletion */
101 #define RENAME 3 /* setup for file renaming */
102 #define OPMASK 3 /* mask for operation */
103 /*
104 * namei operational modifier flags, stored in ni_cnd.flags
105 */
106 #define LOCKLEAF 0x0004 /* lock inode on return */
107 #define LOCKPARENT 0x0008 /* want parent vnode returned locked */
108 #define WANTPARENT 0x0010 /* want parent vnode returned unlocked */
109 #define NOCACHE 0x0020 /* name must not be left in cache */
110 #define FOLLOW 0x0040 /* follow symbolic links */
111 #define NOOBJ 0x0080 /* don't create object */
112 #define LOCKSHARED 0x0100 /* Shared lock leaf */
113 #define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
114 #define MODMASK 0x01fc /* mask of operational modifiers */
115 /*
116 * Namei parameter descriptors.
117 *
118 * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
119 * If the caller of namei sets the flag (for example execve wants to
120 * know the name of the program that is being executed), then it must
121 * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
122 * be freed by either the commit routine or the VOP_ABORT routine.
123 * SAVESTART is set only by the callers of namei. It implies SAVENAME
124 * plus the addition of saving the parent directory that contains the
125 * name in ni_startdir. It allows repeated calls to lookup for the
126 * name being sought. The caller is responsible for releasing the
127 * buffer and for vrele'ing ni_startdir.
128 */
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 PDIRUNLOCK 0x200000 /* filesystem lookup() unlocked parent dir */
142 #define NOCROSSMOUNT 0x400000 /* do not cross mount points */
143 #define NOMACCHECK 0x800000 /* do not perform MAC checks */
144 #define PARAMASK 0xfffe00 /* mask of parameter descriptors */
145
146 /*
147 * Initialization of a nameidata structure.
148 */
149 static void NDINIT(struct nameidata *, u_long, u_long, enum uio_seg,
150 const char *, struct thread *);
151 static __inline void
152 NDINIT(struct nameidata *ndp,
153 u_long op, u_long flags,
154 enum uio_seg segflg,
155 const char *namep,
156 struct thread *td)
157 {
158 ndp->ni_cnd.cn_nameiop = op;
159 ndp->ni_cnd.cn_flags = flags;
160 ndp->ni_segflg = segflg;
161 ndp->ni_dirp = namep;
162 ndp->ni_cnd.cn_thread = td;
163 }
164
165 #define NDF_NO_DVP_RELE 0x00000001
166 #define NDF_NO_DVP_UNLOCK 0x00000002
167 #define NDF_NO_DVP_PUT 0x00000003
168 #define NDF_NO_VP_RELE 0x00000004
169 #define NDF_NO_VP_UNLOCK 0x00000008
170 #define NDF_NO_VP_PUT 0x0000000c
171 #define NDF_NO_STARTDIR_RELE 0x00000010
172 #define NDF_NO_FREE_PNBUF 0x00000020
173 #define NDF_ONLY_PNBUF (~NDF_NO_FREE_PNBUF)
174
175 void NDFREE(struct nameidata *, const u_int);
176
177 int namei(struct nameidata *ndp);
178 int lookup(struct nameidata *ndp);
179 int relookup(struct vnode *dvp, struct vnode **vpp,
180 struct componentname *cnp);
181 #endif
182
183 /*
184 * Stats on usefulness of namei caches.
185 */
186 struct nchstats {
187 long ncs_goodhits; /* hits that we can really use */
188 long ncs_neghits; /* negative hits that we can use */
189 long ncs_badhits; /* hits we must drop */
190 long ncs_falsehits; /* hits with id mismatch */
191 long ncs_miss; /* misses */
192 long ncs_long; /* long names that ignore cache */
193 long ncs_pass2; /* names found with passes == 2 */
194 long ncs_2passes; /* number of times we attempt it */
195 };
196
197 extern struct nchstats nchstats;
198
199 #endif /* !_SYS_NAMEI_H_ */
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