xref: /minix/sys/sys/namei.h (revision 0a6a1f1d)
1 /*	$NetBSD: namei.h,v 1.93 2015/04/21 03:19:03 riastradh Exp $	*/
2 
3 
4 /*
5  * WARNING: GENERATED FILE.  DO NOT EDIT
6  * (edit namei.src and run make namei in src/sys/sys)
7  *   by:   NetBSD: gennameih.awk,v 1.5 2009/12/23 14:17:19 pooka Exp
8  *   from: NetBSD: namei.src,v 1.37 2015/04/21 03:18:21 riastradh Exp
9  */
10 
11 /*
12  * Copyright (c) 1985, 1989, 1991, 1993
13  *	The Regents of the University of California.  All rights reserved.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  * 3. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  *
39  *	@(#)namei.h	8.5 (Berkeley) 8/20/94
40  */
41 
42 #ifndef _SYS_NAMEI_H_
43 #define	_SYS_NAMEI_H_
44 
45 #include <sys/queue.h>
46 #include <sys/mutex.h>
47 
48 #ifdef _KERNEL
49 #include <sys/kauth.h>
50 
51 /*
52  * Abstraction for a single pathname.
53  *
54  * This contains both the pathname string and (eventually) all
55  * metadata that determines how the path is to be interpreted.
56  * It is an opaque structure; the implementation is in vfs_lookup.c.
57  *
58  * To call namei, first set up a pathbuf with pathbuf_create or
59  * pathbuf_copyin, then do NDINIT(), then call namei, then AFTER THE
60  * STRUCT NAMEIDATA IS DEAD, call pathbuf_destroy. Don't destroy the
61  * pathbuf before you've finished using the nameidata, or mysterious
62  * bad things may happen.
63  *
64  * pathbuf_assimilate is like pathbuf_create but assumes ownership of
65  * the string buffer passed in, which MUST BE of size PATH_MAX and
66  * have been allocated with PNBUF_GET(). This should only be used when
67  * absolutely necessary; e.g. nfsd uses it for loading paths from
68  * mbufs.
69  */
70 struct pathbuf;
71 
72 struct pathbuf *pathbuf_create(const char *path);
73 struct pathbuf *pathbuf_assimilate(char *path);
74 int pathbuf_copyin(const char *userpath, struct pathbuf **ret);
75 void pathbuf_destroy(struct pathbuf *);
76 
77 /* get a copy of the (current) path string */
78 void pathbuf_copystring(const struct pathbuf *, char *buf, size_t maxlen);
79 
80 /* hold a reference copy of the original path string */
81 const char *pathbuf_stringcopy_get(struct pathbuf *);
82 void pathbuf_stringcopy_put(struct pathbuf *, const char *);
83 
84 // XXX remove this
85 int pathbuf_maybe_copyin(const char *userpath, enum uio_seg seg, struct pathbuf **ret);
86 
87 /*
88  * Lookup parameters: this structure describes the subset of
89  * information from the nameidata structure that is passed
90  * through the VOP interface.
91  */
92 struct componentname {
93 	/*
94 	 * Arguments to lookup.
95 	 */
96 	uint32_t	cn_nameiop;	/* namei operation */
97 	uint32_t	cn_flags;	/* flags to namei */
98 	kauth_cred_t 	cn_cred;	/* credentials */
99 	/*
100 	 * Shared between lookup and commit routines.
101 	 */
102 	const char 	*cn_nameptr;	/* pointer to looked up name */
103 	size_t		cn_namelen;	/* length of looked up comp */
104 	size_t		cn_consume;	/* chars to consume in lookup */
105 };
106 
107 /*
108  * Encapsulation of namei parameters.
109  */
110 struct nameidata {
111 	/*
112 	 * Arguments to namei/lookup.
113 	 */
114 	struct vnode *ni_atdir;		/* startup dir, cwd if null */
115 	struct pathbuf *ni_pathbuf;	/* pathname container */
116 	char *ni_pnbuf;			/* extra pathname buffer ref (XXX) */
117 	/*
118 	 * Arguments to lookup.
119 	 */
120 	struct	vnode *ni_rootdir;	/* logical root directory */
121 	struct	vnode *ni_erootdir;	/* emulation root directory */
122 	/*
123 	 * Results: returned from/manipulated by lookup
124 	 */
125 	struct	vnode *ni_vp;		/* vnode of result */
126 	struct	vnode *ni_dvp;		/* vnode of intermediate directory */
127 	/*
128 	 * Shared between namei and lookup/commit routines.
129 	 */
130 	size_t		ni_pathlen;	/* remaining chars in path */
131 	const char	*ni_next;	/* next location in pathname */
132 	unsigned int	ni_loopcnt;	/* count of symlinks encountered */
133 	/*
134 	 * Lookup parameters: this structure describes the subset of
135 	 * information from the nameidata structure that is passed
136 	 * through the VOP interface.
137 	 */
138 	struct componentname ni_cnd;
139 };
140 
141 /*
142  * namei operations
143  */
144 #define	LOOKUP		0	/* perform name lookup only */
145 #define	CREATE		1	/* setup for file creation */
146 #define	DELETE		2	/* setup for file deletion */
147 #define	RENAME		3	/* setup for file renaming */
148 #define	OPMASK		3	/* mask for operation */
149 /*
150  * namei operational modifier flags, stored in ni_cnd.cn_flags
151  */
152 #define	LOCKLEAF	0x00000004	/* lock inode on return */
153 #define	LOCKPARENT	0x00000008	/* want parent vnode returned locked */
154 #define	TRYEMULROOT	0x00000010	/* try relative to emulation root
155 					   first */
156 #define	NOCACHE		0x00000020	/* name must not be left in cache */
157 #define	FOLLOW		0x00000040	/* follow symbolic links */
158 #define	NOFOLLOW	0x00000000	/* do not follow symbolic links
159 					   (pseudo) */
160 #define	EMULROOTSET	0x00000080	/* emulation root already
161 					   in ni_erootdir */
162 #define	NOCHROOT	0x01000000	/* no chroot on abs path lookups */
163 #define	MODMASK		0x010000fc	/* mask of operational modifiers */
164 /*
165  * Namei parameter descriptors.
166  */
167 #define	NOCROSSMOUNT	0x0000100	/* do not cross mount points */
168 #define	RDONLY		0x0000200	/* lookup with read-only semantics */
169 #define	ISDOTDOT	0x0002000	/* current component name is .. */
170 #define	MAKEENTRY	0x0004000	/* entry is to be added to name cache */
171 #define	ISLASTCN	0x0008000	/* this is last component of pathname */
172 #define	ISWHITEOUT	0x0020000	/* found whiteout */
173 #define	DOWHITEOUT	0x0040000	/* do whiteouts */
174 #define	REQUIREDIR	0x0080000	/* must be a directory */
175 #define	CREATEDIR	0x0200000	/* trailing slashes are ok */
176 #define	PARAMASK	0x02ee300	/* mask of parameter descriptors */
177 
178 /*
179  * Initialization of a nameidata structure.
180  */
181 #define NDINIT(ndp, op, flags, pathbuf) { \
182 	(ndp)->ni_cnd.cn_nameiop = op; \
183 	(ndp)->ni_cnd.cn_flags = flags; \
184 	(ndp)->ni_atdir = NULL; \
185 	(ndp)->ni_pathbuf = pathbuf; \
186 	(ndp)->ni_cnd.cn_cred = kauth_cred_get(); \
187 }
188 
189 /*
190  * Use this to set the start directory for openat()-type operations.
191  */
192 #define NDAT(ndp, dir) {			\
193 	(ndp)->ni_atdir = (dir);		\
194 }
195 
196 #endif
197 
198 /*
199  * This structure describes the elements in the cache of recent
200  * names looked up by namei. NCHNAMLEN is sized to make structure
201  * size a power of two to optimize allocations.  Minimum reasonable
202  * size is 15.
203  */
204 
205 #define	NCHNAMLEN	31	/* maximum name segment length we bother with */
206 
207 /*
208  * Namecache entry.  This structure is arranged so that frequently
209  * accessed and mostly read-only data is toward the front, with
210  * infrequently accessed data and the lock towards the rear.  The
211  * lock is then more likely to be in a seperate cache line.
212  */
213 struct	namecache {
214 	LIST_ENTRY(namecache) nc_hash;	/* hash chain */
215 	LIST_ENTRY(namecache) nc_vhash;	/* directory hash chain */
216 	struct	vnode *nc_dvp;		/* vnode of parent of name */
217 	struct	vnode *nc_vp;		/* vnode the name refers to */
218 	int	nc_flags;		/* copy of componentname's ISWHITEOUT */
219 	char	nc_nlen;		/* length of name */
220 	char	nc_name[NCHNAMLEN];	/* segment name */
221 	void	*nc_gcqueue;		/* queue for garbage collection */
222 	TAILQ_ENTRY(namecache) nc_lru;	/* psuedo-lru chain */
223 	LIST_ENTRY(namecache) nc_dvlist;
224 	LIST_ENTRY(namecache) nc_vlist;
225 	kmutex_t nc_lock;		/* lock on this entry */
226 	int	nc_hittime;		/* last time scored a hit */
227 };
228 
229 #ifdef _KERNEL
230 #include <sys/pool.h>
231 
232 struct mount;
233 struct cpu_info;
234 
235 extern pool_cache_t pnbuf_cache;	/* pathname buffer cache */
236 
237 #define	PNBUF_GET()	((char *)pool_cache_get(pnbuf_cache, PR_WAITOK))
238 #define	PNBUF_PUT(pnb)	pool_cache_put(pnbuf_cache, (void *)(pnb))
239 
240 /*
241  * Typesafe flags for namei_simple/nameiat_simple.
242  *
243  * This encoding is not optimal but serves the important purpose of
244  * not being type-compatible with the regular namei flags.
245  */
246 struct namei_simple_flags_type; /* Opaque. */
247 typedef const struct namei_simple_flags_type *namei_simple_flags_t; /* Gross. */
248 extern const namei_simple_flags_t
249 	NSM_NOFOLLOW_NOEMULROOT,
250 	NSM_NOFOLLOW_TRYEMULROOT,
251 	NSM_FOLLOW_NOEMULROOT,
252 	NSM_FOLLOW_TRYEMULROOT;
253 
254 /*
255  * namei(at)?_simple_* - the simple cases of namei, with no struct
256  *                       nameidata involved.
257  *
258  * namei_simple_kernel takes a kernel-space path as the first argument.
259  * namei_simple_user takes a user-space path as the first argument.
260  * The nameiat_simple_* variants handle relative path using the given
261  * directory vnode instead of current directory.
262  *
263  * A namei call can be converted to namei_simple_* if:
264  *    - the second arg to NDINIT is LOOKUP;
265  *    - it does not need the parent vnode, nd.ni_dvp;
266  *    - the only flags it uses are (NO)FOLLOW and TRYEMULROOT;
267  *    - it does not do anything else gross with the contents of nd.
268  */
269 int namei_simple_kernel(const char *, namei_simple_flags_t, struct vnode **);
270 int namei_simple_user(const char *, namei_simple_flags_t, struct vnode **);
271 int nameiat_simple_kernel(struct vnode *, const char *, namei_simple_flags_t,
272     struct vnode **);
273 int nameiat_simple_user(struct vnode *, const char *, namei_simple_flags_t,
274     struct vnode **);
275 
276 int	namei(struct nameidata *);
277 uint32_t namei_hash(const char *, const char **);
278 int	lookup_for_nfsd(struct nameidata *, struct vnode *, int neverfollow);
279 int	lookup_for_nfsd_index(struct nameidata *, struct vnode *);
280 int	relookup(struct vnode *, struct vnode **, struct componentname *, int);
281 void	cache_purge1(struct vnode *, const char *, size_t, int);
282 #define	PURGE_PARENTS	1
283 #define	PURGE_CHILDREN	2
284 #define	cache_purge(vp)	cache_purge1((vp),NULL,0,PURGE_PARENTS|PURGE_CHILDREN)
285 int	cache_lookup(struct vnode *, const char *, size_t, uint32_t, uint32_t,
286 			int *, struct vnode **);
287 int	cache_lookup_raw(struct vnode *, const char *, size_t, uint32_t,
288 			int *, struct vnode **);
289 int	cache_revlookup(struct vnode *, struct vnode **, char **, char *);
290 void	cache_enter(struct vnode *, struct vnode *,
291 			const char *, size_t, uint32_t);
292 void	nchinit(void);
293 void	nchreinit(void);
294 void	namecache_count_pass2(void);
295 void	namecache_count_2passes(void);
296 void	cache_cpu_init(struct cpu_info *);
297 void	cache_purgevfs(struct mount *);
298 void	namecache_print(struct vnode *, void (*)(const char *, ...)
299     __printflike(1, 2));
300 
301 #endif
302 
303 /*
304  * Stats on usefulness of namei caches.  A couple of structures are
305  * used for counting, with members having the same names but different
306  * types.  Containerize member names with the preprocessor to avoid
307  * cut-'n'-paste.  A (U) in the comment documents values that are
308  * incremented unlocked; we may treat these specially.
309  */
310 #define	_NAMEI_CACHE_STATS(type) {					\
311 	type	ncs_goodhits;	/* hits that we can really use (U) */	\
312 	type	ncs_neghits;	/* negative hits that we can use */	\
313 	type	ncs_badhits;	/* hits we must drop */			\
314 	type	ncs_falsehits;	/* hits with id mismatch (U) */		\
315 	type	ncs_miss;	/* misses */				\
316 	type	ncs_long;	/* long names that ignore cache */	\
317 	type	ncs_pass2;	/* names found with passes == 2 (U) */	\
318 	type	ncs_2passes;	/* number of times we attempt it (U) */	\
319 	type	ncs_revhits;	/* reverse-cache hits */		\
320 	type	ncs_revmiss;	/* reverse-cache misses */		\
321 }
322 
323 /*
324  * Sysctl deals with a uint64_t version of the stats and summary
325  * totals are kept that way.
326  */
327 struct	nchstats _NAMEI_CACHE_STATS(uint64_t);
328 
329 /* #endif !_SYS_NAMEI_H_ (generated by gennameih.awk) */
330 
331 /* Definitions match above, but with NAMEI_ prefix */
332 #define NAMEI_LOOKUP	0
333 #define NAMEI_CREATE	1
334 #define NAMEI_DELETE	2
335 #define NAMEI_RENAME	3
336 #define NAMEI_OPMASK	3
337 #define NAMEI_LOCKLEAF	0x00000004
338 #define NAMEI_LOCKPARENT	0x00000008
339 #define NAMEI_TRYEMULROOT	0x00000010
340 #define NAMEI_NOCACHE	0x00000020
341 #define NAMEI_FOLLOW	0x00000040
342 #define NAMEI_NOFOLLOW	0x00000000
343 #define NAMEI_EMULROOTSET	0x00000080
344 #define NAMEI_NOCHROOT	0x01000000
345 #define NAMEI_MODMASK	0x010000fc
346 #define NAMEI_NOCROSSMOUNT	0x0000100
347 #define NAMEI_RDONLY	0x0000200
348 #define NAMEI_ISDOTDOT	0x0002000
349 #define NAMEI_MAKEENTRY	0x0004000
350 #define NAMEI_ISLASTCN	0x0008000
351 #define NAMEI_ISWHITEOUT	0x0020000
352 #define NAMEI_DOWHITEOUT	0x0040000
353 #define NAMEI_REQUIREDIR	0x0080000
354 #define NAMEI_CREATEDIR	0x0200000
355 #define NAMEI_PARAMASK	0x02ee300
356 
357 #endif /* !_SYS_NAMEI_H_ */
358