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
32#ifndef _SYS_NAMEI_H_
33#define _SYS_NAMEI_H_
34
35#include <sys/caprights.h>
36#include <sys/filedesc.h>
37#include <sys/queue.h>
38#include <sys/_seqc.h>
39#include <sys/_uio.h>
40
41#include <vm/uma.h>
42
43enum nameiop { LOOKUP, CREATE, DELETE, RENAME };
44
45struct componentname {
46 /*
47 * Arguments to lookup.
48 */
49 u_int64_t cn_flags; /* flags to namei */
50 struct ucred *cn_cred; /* credentials */
51 enum nameiop cn_nameiop; /* namei operation */
52 int cn_lkflags; /* Lock flags LK_EXCLUSIVE or LK_SHARED */
53 /*
54 * Shared between lookup and commit routines.
55 */
56 char *cn_pnbuf; /* pathname buffer */
57 char *cn_nameptr; /* pointer to looked up name */
58 long cn_namelen; /* length of looked up component */
59};
60
61struct nameicap_tracker;
62TAILQ_HEAD(nameicap_tracker_head, nameicap_tracker);
63
64/*
65 * Encapsulation of namei parameters.
66 */
67struct nameidata {
68 /*
69 * Arguments to namei/lookup.
70 */
71 const char *ni_dirp; /* pathname pointer */
72 enum uio_seg ni_segflg; /* location of pathname */
73 const cap_rights_t *ni_rightsneeded; /* rights needed to look up vnode */
74 /*
75 * Arguments to lookup.
76 */
77 struct vnode *ni_startdir; /* starting directory */
78 struct vnode *ni_rootdir; /* logical root directory */
79 struct vnode *ni_topdir; /* logical top directory */
80 int ni_dirfd; /* starting directory for *at functions */
81 int ni_lcf; /* local call flags */
82 /*
83 * Results: returned from namei
84 */
85 struct filecaps ni_filecaps; /* rights the *at base has */
86 /*
87 * Results: returned from/manipulated by lookup
88 */
89 struct vnode *ni_vp; /* vnode of result */
90 struct vnode *ni_dvp; /* vnode of intermediate directory */
91 /*
92 * Results: flags returned from namei
93 */
94 u_int ni_resflags;
95 /*
96 * Debug for validating API use by the callers.
97 */
98 u_short ni_debugflags;
99 /*
100 * Shared between namei and lookup/commit routines.
101 */
102 u_short ni_loopcnt; /* count of symlinks encountered */
103 size_t ni_pathlen; /* remaining chars in path */
104 char *ni_next; /* next location in pathname */
105 /*
106 * Lookup parameters: this structure describes the subset of
107 * information from the nameidata structure that is passed
108 * through the VOP interface.
109 */
110 struct componentname ni_cnd;
111
112 /* Serving RBENEATH. */
113 struct nameicap_tracker_head ni_cap_tracker;
114 struct vnode *ni_rbeneath_dpp;
115 struct mount *ni_nctrack_mnt;
116
117 /*
118 * Private helper data for UFS, must be at the end. See
119 * NDINIT_PREFILL().
120 */
121 seqc_t ni_dvp_seqc;
122 seqc_t ni_vp_seqc;
123};
124
125#ifdef _KERNEL
126
127enum cache_fpl_status { CACHE_FPL_STATUS_DESTROYED, CACHE_FPL_STATUS_ABORTED,
128 CACHE_FPL_STATUS_PARTIAL, CACHE_FPL_STATUS_HANDLED, CACHE_FPL_STATUS_UNSET };
129int cache_fplookup(struct nameidata *ndp, enum cache_fpl_status *status,
130 struct pwd **pwdp);
131
132/*
133 * Flags for namei.
134 *
135 * If modifying the list make sure to check whether NDVALIDATE needs updating.
136 */
137
138/*
139 * Debug.
140 */
141#define NAMEI_DBG_INITED 0x0001
142#define NAMEI_DBG_CALLED 0x0002
143#define NAMEI_DBG_HADSTARTDIR 0x0004
144
145/*
146 * namei operational modifier flags, stored in ni_cnd.flags
147 */
148#define NC_NOMAKEENTRY 0x0001 /* name must not be added to cache */
149#define NC_KEEPPOSENTRY 0x0002 /* don't evict a positive entry */
150#define NOCACHE NC_NOMAKEENTRY /* for compatibility with older code */
151#define LOCKLEAF 0x0004 /* lock vnode on return */
152#define LOCKPARENT 0x0008 /* want parent vnode returned locked */
153#define WANTPARENT 0x0010 /* want parent vnode returned unlocked */
154#define FAILIFEXISTS 0x0020 /* return EEXIST if found */
155#define FOLLOW 0x0040 /* follow symbolic links */
156#define EMPTYPATH 0x0080 /* Allow empty path for *at */
157#define LOCKSHARED 0x0100 /* Shared lock leaf */
158#define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
159#define RBENEATH 0x100000000ULL /* No escape, even tmp, from start dir */
160#define NAMEILOOKUP 0x200000000ULL /* cnp is embedded in nameidata */
161#define MODMASK 0xf000001ffULL /* mask of operational modifiers */
162
163/*
164 * Namei parameter descriptors.
165 */
166#define RDONLY 0x00000200 /* lookup with read-only semantics */
167#define ISRESTARTED 0x00000400 /* restarted namei */
168#define IGNOREWHITEOUT 0x00000800 /* ignore whiteouts, e.g. when checking if a dir is empty */
169#define ISWHITEOUT 0x00001000 /* found whiteout */
170#define DOWHITEOUT 0x00002000 /* do whiteouts */
171#define WILLBEDIR 0x00004000 /* new files will be dirs; allow trailing / */
172#define ISOPEN 0x00008000 /* caller is opening; return a real vnode. */
173#define NOCROSSMOUNT 0x00010000 /* do not cross mount points */
174#define NOMACCHECK 0x00020000 /* do not perform MAC checks */
175#define AUDITVNODE1 0x00040000 /* audit the looked up vnode information */
176#define AUDITVNODE2 0x00080000 /* audit the looked up vnode information */
177#define NOCAPCHECK 0x00100000 /* do not perform capability checks */
178#define OPENREAD 0x00200000 /* open for reading */
179#define OPENWRITE 0x00400000 /* open for writing */
180#define WANTIOCTLCAPS 0x00800000 /* leave ioctl caps for the caller */
181#define OPENNAMED 0x01000000 /* opening a named attribute (dir) */
182#define NOEXECCHECK 0x02000000 /* do not perform exec check on dir */
183#define MAKEENTRY 0x04000000 /* entry is to be added to name cache */
184#define ISSYMLINK 0x08000000 /* symlink needs interpretation */
185#define ISLASTCN 0x10000000 /* this is last component of pathname */
186#define ISDOTDOT 0x20000000 /* current component name is .. */
187#define TRAILINGSLASH 0x40000000 /* path ended in a slash */
188#define CREATENAMED 0x80000000 /* create a named attribute dir */
189#define PARAMASK 0xfffffe00 /* mask of parameter descriptors */
190
191/*
192 * Flags which must not be passed in by callers.
193 */
194#define NAMEI_INTERNAL_FLAGS \
195 (NOEXECCHECK | MAKEENTRY | ISSYMLINK | ISLASTCN | ISDOTDOT | \
196 TRAILINGSLASH | ISRESTARTED)
197
198/*
199 * Namei results flags
200 */
201#define NIRES_ABS 0x00000001 /* Path was absolute */
202#define NIRES_STRICTREL 0x00000002 /* Restricted lookup result */
203#define NIRES_EMPTYPATH 0x00000004 /* EMPTYPATH used */
204#define NIRES_BENEATH 0x00000008 /* O_RESOLVE_BENEATH is to be inherited */
205
206/*
207 * Flags in ni_lcf, valid for the duration of the namei call.
208 */
209#define NI_LCF_STRICTREL 0x0001 /* relative lookup only */
210#define NI_LCF_CAP_DOTDOT 0x0002 /* ".." in strictrelative case */
211/* Track capability restrictions seperately for violation ktracing. */
212#define NI_LCF_STRICTREL_KTR 0x0004 /* trace relative lookups */
213#define NI_LCF_CAP_DOTDOT_KTR 0x0008 /* ".." in strictrelative case */
214#define NI_LCF_KTR_FLAGS (NI_LCF_STRICTREL_KTR | NI_LCF_CAP_DOTDOT_KTR)
215
216/*
217 * Initialization of a nameidata structure.
218 */
219#define NDINIT(ndp, op, flags, segflg, namep) \
220 NDINIT_ALL(ndp, op, flags, segflg, namep, AT_FDCWD, NULL, &cap_no_rights)
221#define NDINIT_AT(ndp, op, flags, segflg, namep, dirfd) \
222 NDINIT_ALL(ndp, op, flags, segflg, namep, dirfd, NULL, &cap_no_rights)
223#define NDINIT_ATRIGHTS(ndp, op, flags, segflg, namep, dirfd, rightsp) \
224 NDINIT_ALL(ndp, op, flags, segflg, namep, dirfd, NULL, rightsp)
225#define NDINIT_ATVP(ndp, op, flags, segflg, namep, vp) \
226 NDINIT_ALL(ndp, op, flags, segflg, namep, AT_FDCWD, vp, &cap_no_rights)
227
228/*
229 * Note the constant pattern may *hide* bugs.
230 * Note also that we enable debug checks for non-TIED KLDs
231 * so that they can run on an INVARIANTS kernel without tripping over
232 * assertions on ni_debugflags state.
233 */
234#if defined(INVARIANTS) || (defined(KLD_MODULE) && !defined(KLD_TIED))
235#define NDINIT_PREFILL(arg) memset(arg, 0xff, offsetof(struct nameidata, \
236 ni_dvp_seqc))
237#define NDINIT_DBG(arg) { (arg)->ni_debugflags = NAMEI_DBG_INITED; }
238#define NDREINIT_DBG(arg) { \
239 if (((arg)->ni_debugflags & NAMEI_DBG_INITED) == 0) \
240 panic("namei data not inited"); \
241 if (((arg)->ni_debugflags & NAMEI_DBG_HADSTARTDIR) != 0) \
242 panic("NDREINIT on namei data with NAMEI_DBG_HADSTARTDIR"); \
243 if ((arg)->ni_nctrack_mnt != NULL) \
244 panic("NDREINIT on namei data with leaked ni_nctrack_mnt"); \
245 if (!TAILQ_EMPTY(&(arg)->ni_cap_tracker)) \
246 panic("NDREINIT on namei data with leaked ni_cap_tracker"); \
247 (arg)->ni_debugflags = NAMEI_DBG_INITED; \
248}
249#else
250#define NDINIT_PREFILL(arg) do { } while (0)
251#define NDINIT_DBG(arg) do { } while (0)
252#define NDREINIT_DBG(arg) do { } while (0)
253#endif
254
255#define NDINIT_ALL(ndp, op, flags, segflg, namep, dirfd, startdir, rightsp) \
256do { \
257 struct nameidata *_ndp = (ndp); \
258 const cap_rights_t *_rightsp = (rightsp); \
259 MPASS(_rightsp != NULL); \
260 NDINIT_PREFILL(_ndp); \
261 NDINIT_DBG(_ndp); \
262 _ndp->ni_cnd.cn_nameiop = op; \
263 _ndp->ni_cnd.cn_flags = (flags) | NAMEILOOKUP; \
264 _ndp->ni_segflg = segflg; \
265 _ndp->ni_dirp = namep; \
266 _ndp->ni_dirfd = dirfd; \
267 _ndp->ni_startdir = startdir; \
268 _ndp->ni_resflags = 0; \
269 filecaps_init(&_ndp->ni_filecaps); \
270 _ndp->ni_rightsneeded = _rightsp; \
271 _ndp->ni_rbeneath_dpp = NULL; \
272 _ndp->ni_nctrack_mnt = NULL; \
273 TAILQ_INIT(&_ndp->ni_cap_tracker); \
274} while (0)
275
276#define NDREINIT(ndp) do { \
277 struct nameidata *_ndp = (ndp); \
278 NDREINIT_DBG(_ndp); \
279 filecaps_free(&_ndp->ni_filecaps); \
280 _ndp->ni_resflags = 0; \
281 _ndp->ni_startdir = NULL; \
282 _ndp->ni_cnd.cn_flags &= ~NAMEI_INTERNAL_FLAGS; \
283} while (0)
284
285#define NDPREINIT(ndp) do { \
286 (ndp)->ni_dvp_seqc = SEQC_MOD; \
287 (ndp)->ni_vp_seqc = SEQC_MOD; \
288} while (0)
289
290#define NDFREE_IOCTLCAPS(ndp) do { \
291 struct nameidata *_ndp = (ndp); \
292 filecaps_free(&_ndp->ni_filecaps); \
293} while (0)
294
295#define NDFREE_PNBUF(ndp) do { \
296 struct nameidata *_ndp = (ndp); \
297 MPASS(_ndp->ni_cnd.cn_pnbuf != NULL); \
298 uma_zfree(namei_zone, _ndp->ni_cnd.cn_pnbuf); \
299 _ndp->ni_cnd.cn_pnbuf = NULL; \
300} while (0)
301
302int namei(struct nameidata *ndp);
303int vfs_lookup(struct nameidata *ndp);
304bool vfs_lookup_isroot(struct nameidata *ndp, struct vnode *dvp);
305struct nameidata *vfs_lookup_nameidata(struct componentname *cnp);
306int vfs_relookup(struct vnode *dvp, struct vnode **vpp,
307 struct componentname *cnp, bool refstart);
308
309#define namei_setup_rootdir(ndp, cnp, pwd) do { \
310 if (__predict_true((cnp->cn_flags & ISRESTARTED) == 0)) \
311 ndp->ni_rootdir = pwd->pwd_adir; \
312 else \
313 ndp->ni_rootdir = pwd->pwd_rdir; \
314} while (0)
315#endif
316
317/*
318 * Stats on usefulness of namei caches.
319 */
320struct nchstats {
321 long ncs_goodhits; /* hits that we can really use */
322 long ncs_neghits; /* negative hits that we can use */
323 long ncs_badhits; /* hits we must drop */
324 long ncs_falsehits; /* hits with id mismatch */
325 long ncs_miss; /* misses */
326 long ncs_long; /* long names that ignore cache */
327 long ncs_pass2; /* names found with passes == 2 */
328 long ncs_2passes; /* number of times we attempt it */
329};
330
331extern struct nchstats nchstats;
332
333#endif /* !_SYS_NAMEI_H_ */