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 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)namei.h 8.5 (Berkeley) 1/9/95
30 * $FreeBSD: releng/8.2/sys/sys/namei.h 199583 2009-11-20 15:27:52Z jhb $
31 */
32
33 #ifndef _SYS_NAMEI_H_
34 #define _SYS_NAMEI_H_
35
36 #include <sys/queue.h>
37 #include <sys/uio.h>
38
39 struct componentname {
40 /*
41 * Arguments to lookup.
42 */
43 u_long cn_nameiop; /* namei operation */
44 u_int64_t cn_flags; /* flags to namei */
45 struct thread *cn_thread;/* thread requesting lookup */
46 struct ucred *cn_cred; /* credentials */
47 int cn_lkflags; /* Lock flags LK_EXCLUSIVE or LK_SHARED */
48 /*
49 * Shared between lookup and commit routines.
50 */
51 char *cn_pnbuf; /* pathname buffer */
52 char *cn_nameptr; /* pointer to looked up name */
53 long cn_namelen; /* length of looked up component */
54 long cn_consume; /* chars to consume in lookup() */
55 };
56
57 /*
58 * Encapsulation of namei parameters.
59 */
60 struct nameidata {
61 /*
62 * Arguments to namei/lookup.
63 */
64 const char *ni_dirp; /* pathname pointer */
65 enum uio_seg ni_segflg; /* location of pathname */
66 /*
67 * Arguments to lookup.
68 */
69 struct vnode *ni_startdir; /* starting directory */
70 struct vnode *ni_rootdir; /* logical root directory */
71 struct vnode *ni_topdir; /* logical top directory */
72 int ni_dirfd; /* starting directory for *at functions */
73 /*
74 * Results: returned from/manipulated by lookup
75 */
76 struct vnode *ni_vp; /* vnode of result */
77 struct vnode *ni_dvp; /* vnode of intermediate directory */
78 /*
79 * Shared between namei and lookup/commit routines.
80 */
81 size_t ni_pathlen; /* remaining chars in path */
82 char *ni_next; /* next location in pathname */
83 u_int ni_loopcnt; /* count of symlinks encountered */
84 /*
85 * Lookup parameters: this structure describes the subset of
86 * information from the nameidata structure that is passed
87 * through the VOP interface.
88 */
89 struct componentname 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.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 LOCKSHARED 0x0100 /* Shared lock leaf */
110 #define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
111 #define MODMASK 0x01fc /* 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 RDONLY 0x00000200 /* lookup with read-only semantics */
127 #define HASBUF 0x00000400 /* has allocated pathname buffer */
128 #define SAVENAME 0x00000800 /* save pathname buffer */
129 #define SAVESTART 0x00001000 /* save starting directory */
130 #define ISDOTDOT 0x00002000 /* current component name is .. */
131 #define MAKEENTRY 0x00004000 /* entry is to be added to name cache */
132 #define ISLASTCN 0x00008000 /* this is last component of pathname */
133 #define ISSYMLINK 0x00010000 /* symlink needs interpretation */
134 #define ISWHITEOUT 0x00020000 /* found whiteout */
135 #define DOWHITEOUT 0x00040000 /* do whiteouts */
136 #define WILLBEDIR 0x00080000 /* new files will be dirs; allow trailing / */
137 #define ISUNICODE 0x00100000 /* current component name is unicode*/
138 #define ISOPEN 0x00200000 /* caller is opening; return a real vnode. */
139 #define NOCROSSMOUNT 0x00400000 /* do not cross mount points */
140 #define NOMACCHECK 0x00800000 /* do not perform MAC checks */
141 #define MPSAFE 0x01000000 /* namei() must acquire Giant if needed. */
142 #define GIANTHELD 0x02000000 /* namei() is holding giant. */
143 #define AUDITVNODE1 0x04000000 /* audit the looked up vnode information */
144 #define AUDITVNODE2 0x08000000 /* audit the looked up vnode information */
145 #define TRAILINGSLASH 0x10000000 /* path ended in a slash */
146 #define PARAMASK 0x1ffffe00 /* mask of parameter descriptors */
147
148 #define NDHASGIANT(NDP) (((NDP)->ni_cnd.cn_flags & GIANTHELD) != 0)
149
150 /*
151 * Initialization of a nameidata structure.
152 */
153 #define NDINIT(ndp, op, flags, segflg, namep, td) \
154 NDINIT_ALL(ndp, op, flags, segflg, namep, AT_FDCWD, NULL, td)
155 #define NDINIT_AT(ndp, op, flags, segflg, namep, dirfd, td) \
156 NDINIT_ALL(ndp, op, flags, segflg, namep, dirfd, NULL, td)
157 #define NDINIT_ATVP(ndp, op, flags, segflg, namep, vp, td) \
158 NDINIT_ALL(ndp, op, flags, segflg, namep, AT_FDCWD, vp, td)
159
160 static __inline void
161 NDINIT_ALL(struct nameidata *ndp,
162 u_long op, u_long flags,
163 enum uio_seg segflg,
164 const char *namep,
165 int dirfd,
166 struct vnode *startdir,
167 struct thread *td)
168 {
169 ndp->ni_cnd.cn_nameiop = op;
170 ndp->ni_cnd.cn_flags = flags;
171 ndp->ni_segflg = segflg;
172 ndp->ni_dirp = namep;
173 ndp->ni_dirfd = dirfd;
174 ndp->ni_startdir = startdir;
175 ndp->ni_cnd.cn_thread = td;
176 }
177
178 #define NDF_NO_DVP_RELE 0x00000001
179 #define NDF_NO_DVP_UNLOCK 0x00000002
180 #define NDF_NO_DVP_PUT 0x00000003
181 #define NDF_NO_VP_RELE 0x00000004
182 #define NDF_NO_VP_UNLOCK 0x00000008
183 #define NDF_NO_VP_PUT 0x0000000c
184 #define NDF_NO_STARTDIR_RELE 0x00000010
185 #define NDF_NO_FREE_PNBUF 0x00000020
186 #define NDF_ONLY_PNBUF (~NDF_NO_FREE_PNBUF)
187
188 void NDFREE(struct nameidata *, const u_int);
189
190 int namei(struct nameidata *ndp);
191 int lookup(struct nameidata *ndp);
192 int relookup(struct vnode *dvp, struct vnode **vpp,
193 struct componentname *cnp);
194 #endif
195
196 /*
197 * Stats on usefulness of namei caches.
198 */
199 struct nchstats {
200 long ncs_goodhits; /* hits that we can really use */
201 long ncs_neghits; /* negative hits that we can use */
202 long ncs_badhits; /* hits we must drop */
203 long ncs_falsehits; /* hits with id mismatch */
204 long ncs_miss; /* misses */
205 long ncs_long; /* long names that ignore cache */
206 long ncs_pass2; /* names found with passes == 2 */
207 long ncs_2passes; /* number of times we attempt it */
208 };
209
210 extern struct nchstats nchstats;
211
212 #endif /* !_SYS_NAMEI_H_ */
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