xref: /xnu-11417.121.6/bsd/sys/namei.h (revision a1e26a70f38d1d7daa7b49b258e2f8538ad81650)
1 /*
2  * Copyright (c) 2000-2014 Apple Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
7  * as defined in and that are subject to the Apple Public Source License
8  * Version 2.0 (the 'License'). You may not use this file except in
9  * compliance with the License. The rights granted to you under the License
10  * may not be used to create, or enable the creation or redistribution of,
11  * unlawful or unlicensed copies of an Apple operating system, or to
12  * circumvent, violate, or enable the circumvention or violation of, any
13  * terms of an Apple operating system software license agreement.
14  *
15  * Please obtain a copy of the License at
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
17  *
18  * The Original Code and all software distributed under the License are
19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23  * Please see the License for the specific language governing rights and
24  * limitations under the License.
25  *
26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27  */
28 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
29 /*
30  * Copyright (c) 1985, 1989, 1991, 1993
31  *	The Regents of the University of California.  All rights reserved.
32  *
33  * Redistribution and use in source and binary forms, with or without
34  * modification, are permitted provided that the following conditions
35  * are met:
36  * 1. Redistributions of source code must retain the above copyright
37  *    notice, this list of conditions and the following disclaimer.
38  * 2. Redistributions in binary form must reproduce the above copyright
39  *    notice, this list of conditions and the following disclaimer in the
40  *    documentation and/or other materials provided with the distribution.
41  * 3. All advertising materials mentioning features or use of this software
42  *    must display the following acknowledgement:
43  *	This product includes software developed by the University of
44  *	California, Berkeley and its contributors.
45  * 4. Neither the name of the University nor the names of its contributors
46  *    may be used to endorse or promote products derived from this software
47  *    without specific prior written permission.
48  *
49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59  * SUCH DAMAGE.
60  *
61  *	@(#)namei.h	8.4 (Berkeley) 8/20/94
62  */
63 
64 #ifndef _SYS_NAMEI_H_
65 #define _SYS_NAMEI_H_
66 
67 #include <sys/appleapiopts.h>
68 
69 #ifdef KERNEL
70 #define LOCKLEAF        0x0004  /* lock inode on return */
71 #define LOCKPARENT      0x0008  /* want parent vnode returned */
72 #define WANTPARENT      0x0010  /* want parent vnode returned */
73 
74 #ifdef KERNEL_PRIVATE
75 #define CN_SECLUDE_RENAME 0x10000000 /*rename iff ¬(hard-linked ∨ opened ∨ mmaped)*/
76 #define CN_RAW_ENCRYPTED 0x80000000 /* Look-up is for RO raw encrypted access. */
77 #endif
78 
79 #endif // KERNEL
80 
81 #ifdef BSD_KERNEL_PRIVATE
82 
83 /* VFS Supports "/..namedfork/rsrc" access. */
84 #define NAMEDRSRCFORK           NAMEDSTREAMS
85 
86 
87 #include <sys/queue.h>
88 #include <kern/smr.h>
89 #include <sys/uio.h>
90 #include <sys/vnode.h>
91 #include <sys/mount.h>
92 #include <sys/filedesc.h>
93 
94 #define PATHBUFLEN      256
95 
96 /*
97  * Encapsulation of namei parameters.
98  */
99 struct nameidata {
100 	/*
101 	 * Arguments to namei/lookup.
102 	 */
103 	user_addr_t ni_dirp;            /* pathname pointer */
104 	enum    uio_seg ni_segflg;      /* location of pathname */
105 	enum    path_operation ni_op;   /* intended operation, see enum path_operation in vnode.h */
106 	/*
107 	 * Arguments to lookup.
108 	 */
109 	struct  vnode *ni_startdir;     /* starting directory */
110 	struct  vnode *ni_rootdir;      /* logical root directory */
111 	struct  vnode *ni_usedvp;       /* directory passed in via USEDVP */
112 	/*
113 	 * Results: returned from/manipulated by lookup
114 	 */
115 	struct  vnode *ni_vp;           /* vnode of result */
116 	struct  vnode *ni_dvp;          /* vnode of intermediate directory */
117 	/*
118 	 * Shared between namei and lookup/commit routines.
119 	 */
120 	u_int   ni_pathlen;             /* remaining chars in path */
121 	char    *ni_next;               /* next location in pathname */
122 	char    ni_pathbuf[PATHBUFLEN];
123 	u_long  ni_loopcnt;             /* count of symlinks encountered */
124 
125 	struct componentname ni_cnd;
126 	int32_t ni_flag;
127 	int ni_ncgeneration;            /* For a batched vnop, grab generation beforehand */
128 };
129 
130 #define NAMEI_CONTLOOKUP        0x002    /* Continue processing a lookup which was partially processed in a compound VNOP */
131 #define NAMEI_TRAILINGSLASH     0x004    /* There was at least one trailing slash after last component */
132 #define NAMEI_UNFINISHED        0x008    /* We broke off a lookup to do a compound op */
133 
134 /*
135  * XXX Hack: we need to encode the intended VNOP in order to
136  * be able to include information about which operations a filesystem
137  * supports in the decision to break off a lookup early.
138  */
139 #define NAMEI_COMPOUNDOPEN      0x010
140 #define NAMEI_COMPOUNDREMOVE    0x020
141 #define NAMEI_COMPOUNDMKDIR     0x040
142 #define NAMEI_COMPOUNDRMDIR     0x080
143 #define NAMEI_COMPOUNDRENAME    0x100
144 #define NAMEI_COMPOUND_OP_MASK (NAMEI_COMPOUNDOPEN | NAMEI_COMPOUNDREMOVE | NAMEI_COMPOUNDMKDIR | NAMEI_COMPOUNDRMDIR | NAMEI_COMPOUNDRENAME)
145 
146 #define NAMEI_NOFOLLOW_ANY      0x1000  /* no symlinks allowed in the path */
147 #define NAMEI_ROOTDIR           0x2000  /* Limit lookup to ni_rootdir (similar to chroot) */
148 #define NAMEI_RESOLVE_BENEATH   0x4000  /* path must reside in the hierarchy beneath the starting directory */
149 
150 #ifdef KERNEL
151 /*
152  * namei operational modifier flags, stored in ni_cnd.flags
153  * Also includes LOCKLEAF, LOCKPARENT, and WANTPARENT flags, defined above.
154  */
155 #define NOCACHE         0x00000020 /* name must not be left in cache */
156 #define NOFOLLOW        0x00000000 /* do not follow symbolic links (pseudo) */
157 /* public FOLLOW	0x00000040    see vnode.h */
158 #define SHAREDLEAF      0x00000080 /* OK to have shared leaf lock */
159 #define MODMASK         0x100000fc /* mask of operational modifiers */
160 /*
161  * Namei parameter descriptors.
162  *
163  * SAVESTART is set only by the callers of namei. It implies SAVENAME
164  * plus the addition of saving the parent directory that contains the
165  * name in ni_startdir. It allows repeated calls to lookup for the
166  * name being sought. The caller is responsible for releasing the
167  * buffer and for vrele'ing ni_startdir.
168  */
169 #define SAVENAME        0          /* save pathanme buffer ***obsolete */
170 #define NOCROSSMOUNT    0x00000100 /* do not cross mount points */
171 #define RDONLY          0x00000200 /* lookup with read-only semantics */
172 #define HASBUF          0x00000400 /* has allocated pathname buffer */
173 #define DONOTAUTH       0x00000800 /* do not authorize during lookup */
174 #define SAVESTART       0x00001000 /* save starting directory */
175 /* public ISDOTDOT	0x00002000    see vnode.h */
176 /* public MAKEENTRY	0x00004000    see vnode.h */
177 /* public ISLASTCN	0x00008000    see vnode.h */
178 #define ISSYMLINK       0x00010000 /* symlink needs interpretation */
179 /* public ISWHITEOUT	0x00020000    see vnode.h */
180 /* public DOWHITEOUT	0x00040000    see vnode.h */
181 #define WILLBEDIR       0x00080000 /* new files will be dirs; allow trailing / */
182 #define AUDITVNPATH1    0x00100000 /* audit the path/vnode info */
183 #define AUDITVNPATH2    0x00200000 /* audit the path/vnode info */
184 #define USEDVP          0x00400000 /* start the lookup at ndp.ni_dvp */
185 #define CN_VOLFSPATH    0x00800000 /* user path was a volfs style path */
186 #define CN_FIRMLINK_NOFOLLOW    0x01000000 /* Do not follow firm links */
187 #define UNIONCREATED    0x02000000 /* union fs creation of vnode */
188 #if NAMEDRSRCFORK
189 #define CN_WANTSRSRCFORK 0x04000000
190 #define CN_ALLOWRSRCFORK 0x08000000
191 #endif // NAMEDRSRCFORK
192 // CN_SECLUDE_RENAME is defined above as 0x10000000 (SPI)
193 #define CN_NBMOUNTLOOK  0x20000000 /* do not block for cross mount lookups */
194 #ifdef BSD_KERNEL_PRIVATE
195 #define CN_SKIPNAMECACHE        0x40000000      /* skip cache during lookup(), allow FS to handle all components */
196 #endif
197 // CN_RAW_ENCRYPTED	is defined above as 0x80000000 (SPI)
198 
199 /*
200  * Initialization of an nameidata structure.
201  */
202 
203 #define NDINIT(ndp, op, pop, flags, segflg, namep, ctx) { \
204 	(ndp)->ni_cnd.cn_nameiop = op; \
205 	(ndp)->ni_op = pop; \
206 	(ndp)->ni_cnd.cn_flags = flags; \
207 	if ((segflg) == UIO_USERSPACE) { \
208 	        (ndp)->ni_segflg = (vfs_context_is64bit(ctx) ? UIO_USERSPACE64 : UIO_USERSPACE32); \
209 	} \
210 	else { \
211 	        (ndp)->ni_segflg = segflg; \
212 	} \
213 	(ndp)->ni_dirp = namep; \
214 	(ndp)->ni_cnd.cn_context = ctx; \
215 	(ndp)->ni_flag = 0; \
216 	(ndp)->ni_cnd.cn_ndp = (ndp); \
217 }
218 
219 #endif /* KERNEL */
220 
221 /*
222  * This structure describes the elements in the cache of recent
223  * names looked up by namei.
224  */
225 struct  namecache {
226 	TAILQ_ENTRY(namecache)  nc_entry;       /* chain of all entries */
227 	TAILQ_ENTRY(namecache)  nc_child;       /* chain of ncp's that are children of a vp */
228 	union {
229 		LIST_ENTRY(namecache)  nc_link; /* chain of ncp's that 'name' a vp */
230 		TAILQ_ENTRY(namecache) nc_negentry; /* chain of ncp's that 'name' a vp */
231 	} nc_un;
232 	struct smrq_link        nc_hash;        /* hash chain */
233 	uint32_t                nc_vid;         /* vid for nc_vp */
234 	uint32_t                nc_counter;     /* flags */
235 	vnode_t                 nc_dvp;         /* vnode of parent of name */
236 	vnode_t                 nc_vp;          /* vnode the name refers to */
237 	unsigned int            nc_hashval;     /* hashval of stringname */
238 	const char              *nc_name;       /* pointer to segment name in string cache */
239 };
240 
241 #define NC_VALID 0x01  /* counter value with this bit set (i.e. odd number) represents an valid/in-use namecache struct */
242 
243 #ifdef KERNEL
244 
245 int     namei(struct nameidata *ndp);
246 void    nameidone(struct nameidata *);
247 int     lookup(struct nameidata *ndp);
248 int     relookup(struct vnode *dvp, struct vnode **vpp,
249     struct componentname *cnp);
250 #if CONFIG_UNION_MOUNTS
251 int     lookup_traverse_union(vnode_t dvp, vnode_t *new_dvp, vfs_context_t ctx);
252 #endif /* CONFIG_UNION_MOUNTS */
253 int     lookup_check_for_resolve_prefix(char *path, size_t pathbuflen, size_t len, uint32_t *resolve_flags, size_t *prefix_len);
254 void    lookup_compound_vnop_post_hook(int error, vnode_t dvp, vnode_t vp, struct nameidata *ndp, int did_create);
255 void    kdebug_lookup(struct vnode *dp, struct componentname *cnp);
256 
257 /*
258  * namecache function prototypes
259  */
260 void    cache_purgevfs(mount_t mp);
261 int             cache_lookup_path(struct nameidata *ndp, struct componentname *cnp, vnode_t dp,
262     vfs_context_t context, int *dp_authorized, vnode_t last_dp);
263 
264 void            vnode_cache_authorized_action(vnode_t vp, vfs_context_t context, kauth_action_t action);
265 void            vnode_uncache_authorized_action(vnode_t vp, kauth_action_t action);
266 boolean_t       vnode_cache_is_stale(vnode_t vp);
267 boolean_t       vnode_cache_is_authorized(vnode_t vp, vfs_context_t context, kauth_action_t action);
268 int             lookup_validate_creation_path(struct nameidata *ndp);
269 int             namei_compound_available(vnode_t dp, struct nameidata *ndp);
270 
271 #endif /* KERNEL */
272 
273 /*
274  * Stats on usefulness of namei caches.
275  */
276 struct  nchstats {
277 	long    ncs_goodhits;           /* hits that we can really use */
278 	long    ncs_neghits;            /* negative hits that we can use */
279 	long    ncs_badhits;            /* hits we must drop */
280 	long    ncs_miss;               /* misses */
281 	long    ncs_pass2;              /* names found with passes == 2 */
282 	long    ncs_2passes;            /* number of times we attempt it */
283 	long    ncs_stolen;
284 	long    ncs_enters;
285 	long    ncs_deletes;
286 	long    ncs_badvid;
287 };
288 #endif /* BSD_KERNEL_PRIVATE */
289 
290 #endif /* !_SYS_NAMEI_H_ */
291