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/_seqc.h>
42 #include <sys/_uio.h>
43
44 enum nameiop { LOOKUP, CREATE, DELETE, RENAME };
45
46 struct componentname {
47 /*
48 * Arguments to lookup.
49 */
50 u_int64_t cn_origflags; /* flags to namei */
51 u_int64_t cn_flags; /* flags to namei */
52 struct ucred *cn_cred; /* credentials */
53 enum nameiop cn_nameiop; /* namei operation */
54 int cn_lkflags; /* Lock flags LK_EXCLUSIVE or LK_SHARED */
55 /*
56 * Shared between lookup and commit routines.
57 */
58 char *cn_pnbuf; /* pathname buffer */
59 char *cn_nameptr; /* pointer to looked up name */
60 long cn_namelen; /* length of looked up component */
61 };
62
63 struct nameicap_tracker;
64 TAILQ_HEAD(nameicap_tracker_head, nameicap_tracker);
65
66 /*
67 * Encapsulation of namei parameters.
68 */
69 struct nameidata {
70 /*
71 * Arguments to namei/lookup.
72 */
73 const char *ni_dirp; /* pathname pointer */
74 enum uio_seg ni_segflg; /* location of pathname */
75 cap_rights_t *ni_rightsneeded; /* rights required to look up vnode */
76 /*
77 * Arguments to lookup.
78 */
79 struct vnode *ni_startdir; /* starting directory */
80 struct vnode *ni_rootdir; /* logical root directory */
81 struct vnode *ni_topdir; /* logical top directory */
82 int ni_dirfd; /* starting directory for *at functions */
83 int ni_lcf; /* local call flags */
84 /*
85 * Results: returned from namei
86 */
87 struct filecaps ni_filecaps; /* rights the *at base has */
88 /*
89 * Results: returned from/manipulated by lookup
90 */
91 struct vnode *ni_vp; /* vnode of result */
92 struct vnode *ni_dvp; /* vnode of intermediate directory */
93 /*
94 * Results: flags returned from namei
95 */
96 u_int ni_resflags;
97 /*
98 * Debug for validating API use by the callers.
99 */
100 u_short ni_debugflags;
101 /*
102 * Shared between namei and lookup/commit routines.
103 */
104 u_short ni_loopcnt; /* count of symlinks encountered */
105 size_t ni_pathlen; /* remaining chars in path */
106 char *ni_next; /* next location in pathname */
107 /*
108 * Lookup parameters: this structure describes the subset of
109 * information from the nameidata structure that is passed
110 * through the VOP interface.
111 */
112 struct componentname ni_cnd;
113 struct nameicap_tracker_head ni_cap_tracker;
114 /*
115 * Private helper data for UFS, must be at the end. See
116 * NDINIT_PREFILL().
117 */
118 seqc_t ni_dvp_seqc;
119 seqc_t ni_vp_seqc;
120 };
121
122 #ifdef _KERNEL
123
124 enum cache_fpl_status { CACHE_FPL_STATUS_DESTROYED, CACHE_FPL_STATUS_ABORTED,
125 CACHE_FPL_STATUS_PARTIAL, CACHE_FPL_STATUS_HANDLED, CACHE_FPL_STATUS_UNSET };
126 int cache_fplookup(struct nameidata *ndp, enum cache_fpl_status *status,
127 struct pwd **pwdp);
128
129 /*
130 * Flags for namei.
131 *
132 * If modifying the list make sure to check whether NDVALIDATE needs updating.
133 */
134
135 /*
136 * Debug.
137 */
138 #define NAMEI_DBG_INITED 0x0001
139 #define NAMEI_DBG_CALLED 0x0002
140 #define NAMEI_DBG_HADSTARTDIR 0x0004
141
142 /*
143 * namei operational modifier flags, stored in ni_cnd.flags
144 */
145 #define NC_NOMAKEENTRY 0x0001 /* name must not be added to cache */
146 #define NC_KEEPPOSENTRY 0x0002 /* don't evict a positive entry */
147 #define NOCACHE NC_NOMAKEENTRY /* for compatibility with older code */
148 #define LOCKLEAF 0x0004 /* lock vnode on return */
149 #define LOCKPARENT 0x0008 /* want parent vnode returned locked */
150 #define WANTPARENT 0x0010 /* want parent vnode returned unlocked */
151 #define FAILIFEXISTS 0x0020 /* return EEXIST if found */
152 #define FOLLOW 0x0040 /* follow symbolic links */
153 #define EMPTYPATH 0x0080 /* Allow empty path for *at */
154 #define LOCKSHARED 0x0100 /* Shared lock leaf */
155 #define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
156 #define RBENEATH 0x100000000ULL /* No escape, even tmp, from start dir */
157 #define MODMASK 0xf000001ffULL /* mask of operational modifiers */
158
159 /*
160 * Namei parameter descriptors.
161 */
162 #define RDONLY 0x00000200 /* lookup with read-only semantics */
163 /* UNUSED 0x00000400 */
164 /* UNUSED 0x00000800 */
165 #define ISWHITEOUT 0x00001000 /* found whiteout */
166 #define DOWHITEOUT 0x00002000 /* do whiteouts */
167 #define WILLBEDIR 0x00004000 /* new files will be dirs; allow trailing / */
168 #define ISOPEN 0x00008000 /* caller is opening; return a real vnode. */
169 #define NOCROSSMOUNT 0x00010000 /* do not cross mount points */
170 #define NOMACCHECK 0x00020000 /* do not perform MAC checks */
171 #define AUDITVNODE1 0x00040000 /* audit the looked up vnode information */
172 #define AUDITVNODE2 0x00080000 /* audit the looked up vnode information */
173 #define NOCAPCHECK 0x00100000 /* do not perform capability checks */
174 #define OPENREAD 0x00200000 /* open for reading */
175 #define OPENWRITE 0x00400000 /* open for writing */
176 #define WANTIOCTLCAPS 0x00800000 /* leave ioctl caps for the caller */
177 /* UNUSED 0x01000000 */
178 #define NOEXECCHECK 0x02000000 /* do not perform exec check on dir */
179 #define MAKEENTRY 0x04000000 /* entry is to be added to name cache */
180 #define ISSYMLINK 0x08000000 /* symlink needs interpretation */
181 #define ISLASTCN 0x10000000 /* this is last component of pathname */
182 #define ISDOTDOT 0x20000000 /* current component name is .. */
183 #define TRAILINGSLASH 0x40000000 /* path ended in a slash */
184 #define PARAMASK 0x7ffffe00 /* mask of parameter descriptors */
185
186 /*
187 * Flags which must not be passed in by callers.
188 */
189 #define NAMEI_INTERNAL_FLAGS \
190 (NOEXECCHECK | MAKEENTRY | ISSYMLINK | ISLASTCN | ISDOTDOT | \
191 TRAILINGSLASH)
192
193 /*
194 * Namei results flags
195 */
196 #define NIRES_ABS 0x00000001 /* Path was absolute */
197 #define NIRES_STRICTREL 0x00000002 /* Restricted lookup result */
198 #define NIRES_EMPTYPATH 0x00000004 /* EMPTYPATH used */
199
200 /*
201 * Flags in ni_lcf, valid for the duration of the namei call.
202 */
203 #define NI_LCF_STRICTRELATIVE 0x0001 /* relative lookup only */
204 #define NI_LCF_CAP_DOTDOT 0x0002 /* ".." in strictrelative case */
205
206 /*
207 * Initialization of a nameidata structure.
208 */
209 #define NDINIT(ndp, op, flags, segflg, namep) \
210 NDINIT_ALL(ndp, op, flags, segflg, namep, AT_FDCWD, NULL, &cap_no_rights)
211 #define NDINIT_AT(ndp, op, flags, segflg, namep, dirfd) \
212 NDINIT_ALL(ndp, op, flags, segflg, namep, dirfd, NULL, &cap_no_rights)
213 #define NDINIT_ATRIGHTS(ndp, op, flags, segflg, namep, dirfd, rightsp) \
214 NDINIT_ALL(ndp, op, flags, segflg, namep, dirfd, NULL, rightsp)
215 #define NDINIT_ATVP(ndp, op, flags, segflg, namep, vp) \
216 NDINIT_ALL(ndp, op, flags, segflg, namep, AT_FDCWD, vp, &cap_no_rights)
217
218 /*
219 * Note the constant pattern may *hide* bugs.
220 * Note also that we enable debug checks for non-TIED KLDs
221 * so that they can run on an INVARIANTS kernel without tripping over
222 * assertions on ni_debugflags state.
223 */
224 #if defined(INVARIANTS) || (defined(KLD_MODULE) && !defined(KLD_TIED))
225 #define NDINIT_PREFILL(arg) memset(arg, 0xff, offsetof(struct nameidata, \
226 ni_dvp_seqc))
227 #define NDINIT_DBG(arg) { (arg)->ni_debugflags = NAMEI_DBG_INITED; }
228 #define NDREINIT_DBG(arg) { \
229 if (((arg)->ni_debugflags & NAMEI_DBG_INITED) == 0) \
230 panic("namei data not inited"); \
231 if (((arg)->ni_debugflags & NAMEI_DBG_HADSTARTDIR) != 0) \
232 panic("NDREINIT on namei data with NAMEI_DBG_HADSTARTDIR"); \
233 (arg)->ni_debugflags = NAMEI_DBG_INITED; \
234 }
235 #else
236 #define NDINIT_PREFILL(arg) do { } while (0)
237 #define NDINIT_DBG(arg) do { } while (0)
238 #define NDREINIT_DBG(arg) do { } while (0)
239 #endif
240
241 #define NDINIT_ALL(ndp, op, flags, segflg, namep, dirfd, startdir, rightsp) \
242 do { \
243 struct nameidata *_ndp = (ndp); \
244 cap_rights_t *_rightsp = (rightsp); \
245 MPASS(_rightsp != NULL); \
246 NDINIT_PREFILL(_ndp); \
247 NDINIT_DBG(_ndp); \
248 _ndp->ni_cnd.cn_nameiop = op; \
249 _ndp->ni_cnd.cn_flags = flags; \
250 _ndp->ni_segflg = segflg; \
251 _ndp->ni_dirp = namep; \
252 _ndp->ni_dirfd = dirfd; \
253 _ndp->ni_startdir = startdir; \
254 _ndp->ni_resflags = 0; \
255 filecaps_init(&_ndp->ni_filecaps); \
256 _ndp->ni_rightsneeded = _rightsp; \
257 } while (0)
258
259 #define NDREINIT(ndp) do { \
260 struct nameidata *_ndp = (ndp); \
261 NDREINIT_DBG(_ndp); \
262 filecaps_free(&_ndp->ni_filecaps); \
263 _ndp->ni_resflags = 0; \
264 _ndp->ni_startdir = NULL; \
265 } while (0)
266
267 #define NDPREINIT(ndp) do { \
268 (ndp)->ni_dvp_seqc = SEQC_MOD; \
269 (ndp)->ni_vp_seqc = SEQC_MOD; \
270 } while (0)
271
272 #define NDF_NO_DVP_RELE 0x00000001
273 #define NDF_NO_DVP_UNLOCK 0x00000002
274 #define NDF_NO_DVP_PUT 0x00000003
275 #define NDF_NO_VP_RELE 0x00000004
276 #define NDF_NO_VP_UNLOCK 0x00000008
277 #define NDF_NO_VP_PUT 0x0000000c
278 #define NDF_NO_STARTDIR_RELE 0x00000010
279 #define NDF_NO_FREE_PNBUF 0x00000020
280
281 #define NDFREE_IOCTLCAPS(ndp) do { \
282 struct nameidata *_ndp = (ndp); \
283 filecaps_free(&_ndp->ni_filecaps); \
284 } while (0)
285
286 #define NDFREE_PNBUF(ndp) do { \
287 struct nameidata *_ndp = (ndp); \
288 MPASS(_ndp->ni_cnd.cn_pnbuf != NULL); \
289 uma_zfree(namei_zone, _ndp->ni_cnd.cn_pnbuf); \
290 _ndp->ni_cnd.cn_pnbuf = NULL; \
291 } while (0)
292
293 int namei(struct nameidata *ndp);
294 int vfs_lookup(struct nameidata *ndp);
295 int vfs_relookup(struct vnode *dvp, struct vnode **vpp,
296 struct componentname *cnp, bool refstart);
297 #endif
298
299 /*
300 * Stats on usefulness of namei caches.
301 */
302 struct nchstats {
303 long ncs_goodhits; /* hits that we can really use */
304 long ncs_neghits; /* negative hits that we can use */
305 long ncs_badhits; /* hits we must drop */
306 long ncs_falsehits; /* hits with id mismatch */
307 long ncs_miss; /* misses */
308 long ncs_long; /* long names that ignore cache */
309 long ncs_pass2; /* names found with passes == 2 */
310 long ncs_2passes; /* number of times we attempt it */
311 };
312
313 extern struct nchstats nchstats;
314
315 #endif /* !_SYS_NAMEI_H_ */
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