FreeBSD/Linux Kernel Cross Reference
sys/sys/namei.h
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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) 1/9/95
32 * $FreeBSD$
33 */
34
35 #ifndef _SYS_NAMEI_H_
36 #define _SYS_NAMEI_H_
37
38 #include <sys/caprights.h>
39 #include <sys/filedesc.h>
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_int64_t cn_flags; /* flags to namei */
49 struct thread *cn_thread;/* thread requesting lookup */
50 struct ucred *cn_cred; /* credentials */
51 int cn_lkflags; /* Lock flags LK_EXCLUSIVE or LK_SHARED */
52 /*
53 * Shared between lookup and commit routines.
54 */
55 char *cn_pnbuf; /* pathname buffer */
56 char *cn_nameptr; /* pointer to looked up name */
57 long cn_namelen; /* length of looked up component */
58 };
59
60 struct nameicap_tracker;
61 TAILQ_HEAD(nameicap_tracker_head, nameicap_tracker);
62
63 /*
64 * Encapsulation of namei parameters.
65 */
66 struct nameidata {
67 /*
68 * Arguments to namei/lookup.
69 */
70 const char *ni_dirp; /* pathname pointer */
71 enum uio_seg ni_segflg; /* location of pathname */
72 cap_rights_t ni_rightsneeded; /* rights required to look up vnode */
73 /*
74 * Arguments to lookup.
75 */
76 struct vnode *ni_startdir; /* starting directory */
77 struct vnode *ni_rootdir; /* logical root directory */
78 struct vnode *ni_topdir; /* logical top directory */
79 int ni_dirfd; /* starting directory for *at functions */
80 int ni_lcf; /* local call flags */
81 /*
82 * Results: returned from namei
83 */
84 struct filecaps ni_filecaps; /* rights the *at base has */
85 /*
86 * Results: returned from/manipulated by lookup
87 */
88 struct vnode *ni_vp; /* vnode of result */
89 struct vnode *ni_dvp; /* vnode of intermediate directory */
90 /*
91 * Results: flags returned from namei
92 */
93 u_int ni_resflags;
94 /*
95 * Shared between namei and lookup/commit routines.
96 */
97 size_t ni_pathlen; /* remaining chars in path */
98 char *ni_next; /* next location in pathname */
99 u_int ni_loopcnt; /* count of symlinks encountered */
100 /*
101 * Lookup parameters: this structure describes the subset of
102 * information from the nameidata structure that is passed
103 * through the VOP interface.
104 */
105 struct componentname ni_cnd;
106 struct nameicap_tracker_head ni_cap_tracker;
107 };
108
109 #ifdef _KERNEL
110 /*
111 * namei operations
112 */
113 #define LOOKUP 0 /* perform name lookup only */
114 #define CREATE 1 /* setup for file creation */
115 #define DELETE 2 /* setup for file deletion */
116 #define RENAME 3 /* setup for file renaming */
117 #define OPMASK 3 /* mask for operation */
118 /*
119 * namei operational modifier flags, stored in ni_cnd.flags
120 */
121 #define LOCKLEAF 0x0004 /* lock vnode on return */
122 #define LOCKPARENT 0x0008 /* want parent vnode returned locked */
123 #define WANTPARENT 0x0010 /* want parent vnode returned unlocked */
124 #define NOCACHE 0x0020 /* name must not be left in cache */
125 #define FOLLOW 0x0040 /* follow symbolic links */
126 #define LOCKSHARED 0x0100 /* Shared lock leaf */
127 #define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
128 #define RBENEATH 0x100000000ULL /* No escape, even tmp, from start dir */
129 #define MODMASK 0xf000001fcULL /* mask of operational modifiers */
130 /*
131 * Namei parameter descriptors.
132 *
133 * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
134 * If the caller of namei sets the flag (for example execve wants to
135 * know the name of the program that is being executed), then it must
136 * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
137 * be freed by either the commit routine or the VOP_ABORT routine.
138 * SAVESTART is set only by the callers of namei. It implies SAVENAME
139 * plus the addition of saving the parent directory that contains the
140 * name in ni_startdir. It allows repeated calls to lookup for the
141 * name being sought. The caller is responsible for releasing the
142 * buffer and for vrele'ing ni_startdir.
143 */
144 #define RDONLY 0x00000200 /* lookup with read-only semantics */
145 #define HASBUF 0x00000400 /* has allocated pathname buffer */
146 #define SAVENAME 0x00000800 /* save pathname buffer */
147 #define SAVESTART 0x00001000 /* save starting directory */
148 #define ISDOTDOT 0x00002000 /* current component name is .. */
149 #define MAKEENTRY 0x00004000 /* entry is to be added to name cache */
150 #define ISLASTCN 0x00008000 /* this is last component of pathname */
151 #define ISSYMLINK 0x00010000 /* symlink needs interpretation */
152 #define ISWHITEOUT 0x00020000 /* found whiteout */
153 #define DOWHITEOUT 0x00040000 /* do whiteouts */
154 #define WILLBEDIR 0x00080000 /* new files will be dirs; allow trailing / */
155 #define ISUNICODE 0x00100000 /* current component name is unicode*/
156 #define ISOPEN 0x00200000 /* caller is opening; return a real vnode. */
157 #define NOCROSSMOUNT 0x00400000 /* do not cross mount points */
158 #define NOMACCHECK 0x00800000 /* do not perform MAC checks */
159 #define AUDITVNODE1 0x04000000 /* audit the looked up vnode information */
160 #define AUDITVNODE2 0x08000000 /* audit the looked up vnode information */
161 #define TRAILINGSLASH 0x10000000 /* path ended in a slash */
162 #define NOCAPCHECK 0x20000000 /* do not perform capability checks */
163 #define NOEXECCHECK 0x40000000 /* do not perform exec check on dir */
164 #define PARAMASK 0x7ffffe00 /* mask of parameter descriptors */
165
166 /*
167 * Namei results flags
168 */
169 #define NIRES_ABS 0x00000001 /* Path was absolute */
170 #define NIRES_STRICTREL 0x00000002 /* Restricted lookup result */
171
172 /*
173 * Flags in ni_lcf, valid for the duration of the namei call.
174 */
175 #define NI_LCF_STRICTRELATIVE 0x0001 /* relative lookup only */
176 #define NI_LCF_CAP_DOTDOT 0x0002 /* ".." in strictrelative case */
177
178 /*
179 * Initialization of a nameidata structure.
180 */
181 #define NDINIT(ndp, op, flags, segflg, namep, td) \
182 NDINIT_ALL(ndp, op, flags, segflg, namep, AT_FDCWD, NULL, 0, td)
183 #define NDINIT_AT(ndp, op, flags, segflg, namep, dirfd, td) \
184 NDINIT_ALL(ndp, op, flags, segflg, namep, dirfd, NULL, 0, td)
185 #define NDINIT_ATRIGHTS(ndp, op, flags, segflg, namep, dirfd, rightsp, td) \
186 NDINIT_ALL(ndp, op, flags, segflg, namep, dirfd, NULL, rightsp, td)
187 #define NDINIT_ATVP(ndp, op, flags, segflg, namep, vp, td) \
188 NDINIT_ALL(ndp, op, flags, segflg, namep, AT_FDCWD, vp, 0, td)
189
190 void NDINIT_ALL(struct nameidata *ndp, u_long op, u_long flags,
191 enum uio_seg segflg, const char *namep, int dirfd, struct vnode *startdir,
192 cap_rights_t *rightsp, struct thread *td);
193
194 #define NDF_NO_DVP_RELE 0x00000001
195 #define NDF_NO_DVP_UNLOCK 0x00000002
196 #define NDF_NO_DVP_PUT 0x00000003
197 #define NDF_NO_VP_RELE 0x00000004
198 #define NDF_NO_VP_UNLOCK 0x00000008
199 #define NDF_NO_VP_PUT 0x0000000c
200 #define NDF_NO_STARTDIR_RELE 0x00000010
201 #define NDF_NO_FREE_PNBUF 0x00000020
202 #define NDF_ONLY_PNBUF (~NDF_NO_FREE_PNBUF)
203
204 void NDFREE(struct nameidata *, const u_int);
205
206 int namei(struct nameidata *ndp);
207 int lookup(struct nameidata *ndp);
208 int relookup(struct vnode *dvp, struct vnode **vpp,
209 struct componentname *cnp);
210 #endif
211
212 /*
213 * Stats on usefulness of namei caches.
214 */
215 struct nchstats {
216 long ncs_goodhits; /* hits that we can really use */
217 long ncs_neghits; /* negative hits that we can use */
218 long ncs_badhits; /* hits we must drop */
219 long ncs_falsehits; /* hits with id mismatch */
220 long ncs_miss; /* misses */
221 long ncs_long; /* long names that ignore cache */
222 long ncs_pass2; /* names found with passes == 2 */
223 long ncs_2passes; /* number of times we attempt it */
224 };
225
226 extern struct nchstats nchstats;
227
228 #endif /* !_SYS_NAMEI_H_ */
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