Annotation of sys/sys/namei.h, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: namei.h,v 1.20 2007/08/07 07:41:59 thib Exp $ */
2: /* $NetBSD: namei.h,v 1.11 1996/02/09 18:25:20 christos Exp $ */
3:
4: /*
5: * Copyright (c) 1985, 1989, 1991, 1993
6: * The Regents of the University of California. All rights reserved.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: * 3. Neither the name of the University nor the names of its contributors
17: * may be used to endorse or promote products derived from this software
18: * without specific prior written permission.
19: *
20: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30: * SUCH DAMAGE.
31: *
32: * @(#)namei.h 8.4 (Berkeley) 8/20/94
33: */
34:
35: #ifndef _SYS_NAMEI_H_
36: #define _SYS_NAMEI_H_
37:
38: #include <sys/queue.h>
39:
40: /*
41: * Encapsulation of namei parameters.
42: */
43: struct nameidata {
44: /*
45: * Arguments to namei/lookup.
46: */
47: const char *ni_dirp; /* pathname pointer */
48: enum uio_seg ni_segflg; /* location of pathname */
49: /* u_long ni_nameiop; namei operation */
50: /* u_long ni_flags; flags to namei */
51: /* struct proc *ni_proc; process requesting lookup */
52: /*
53: * Arguments to lookup.
54: */
55: /* struct ucred *ni_cred; credentials */
56: struct vnode *ni_startdir; /* starting directory */
57: struct vnode *ni_rootdir; /* logical root directory */
58: /*
59: * Results: returned from/manipulated by lookup
60: */
61: struct vnode *ni_vp; /* vnode of result */
62: struct vnode *ni_dvp; /* vnode of intermediate directory */
63: /*
64: * Shared between namei and lookup/commit routines.
65: */
66: size_t ni_pathlen; /* remaining chars in path */
67: char *ni_next; /* next location in pathname */
68: u_long ni_loopcnt; /* count of symlinks encountered */
69: /*
70: * Lookup parameters: this structure describes the subset of
71: * information from the nameidata structure that is passed
72: * through the VOP interface.
73: */
74: struct componentname {
75: /*
76: * Arguments to lookup.
77: */
78: u_long cn_nameiop; /* namei operation */
79: u_long cn_flags; /* flags to namei */
80: struct proc *cn_proc; /* process requesting lookup */
81: struct ucred *cn_cred; /* credentials */
82: /*
83: * Shared between lookup and commit routines.
84: */
85: char *cn_pnbuf; /* pathname buffer */
86: char *cn_nameptr; /* pointer to looked up name */
87: long cn_namelen; /* length of looked up component */
88: u_int32_t cn_hash; /* hash value of looked up name */
89: long cn_consume; /* chars to consume in lookup() */
90: } ni_cnd;
91: };
92:
93: #ifdef _KERNEL
94: /*
95: * namei operations
96: */
97: #define LOOKUP 0 /* perform name lookup only */
98: #define CREATE 1 /* setup for file creation */
99: #define DELETE 2 /* setup for file deletion */
100: #define RENAME 3 /* setup for file renaming */
101: #define OPMASK 3 /* mask for operation */
102: /*
103: * namei operational modifier flags, stored in ni_cnd.flags
104: */
105: #define LOCKLEAF 0x0004 /* lock inode on return */
106: #define LOCKPARENT 0x0008 /* want parent vnode returned locked */
107: #define WANTPARENT 0x0010 /* want parent vnode returned unlocked */
108: #define NOCACHE 0x0020 /* name must not be left in cache */
109: #define FOLLOW 0x0040 /* follow symbolic links */
110: #define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
111: #define MODMASK 0x00fc /* mask of operational modifiers */
112: /*
113: * Namei parameter descriptors.
114: *
115: * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
116: * If the caller of namei sets the flag (for example execve wants to
117: * know the name of the program that is being executed), then it must
118: * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
119: * be freed by either the commit routine or the VOP_ABORT routine.
120: * SAVESTART is set only by the callers of namei. It implies SAVENAME
121: * plus the addition of saving the parent directory that contains the
122: * name in ni_startdir. It allows repeated calls to lookup for the
123: * name being sought. The caller is responsible for releasing the
124: * buffer and for vrele'ing ni_startdir.
125: */
126: #define NOCROSSMOUNT 0x000100 /* do not cross mount points */
127: #define RDONLY 0x000200 /* lookup with read-only semantics */
128: #define HASBUF 0x000400 /* has allocated pathname buffer */
129: #define SAVENAME 0x000800 /* save pathanme buffer */
130: #define SAVESTART 0x001000 /* save starting directory */
131: #define ISDOTDOT 0x002000 /* current component name is .. */
132: #define MAKEENTRY 0x004000 /* entry is to be added to name cache */
133: #define ISLASTCN 0x008000 /* this is last component of pathname */
134: #define ISSYMLINK 0x010000 /* symlink needs interpretation */
135: #define REQUIREDIR 0x080000 /* must be a directory */
136: #define STRIPSLASHES 0x100000 /* strip trailing slashes */
137: #define PDIRUNLOCK 0x200000 /* vfs_lookup() unlocked parent dir */
138:
139: /*
140: * Initialization of an nameidata structure.
141: */
142: #define NDINIT(ndp, op, flags, segflg, namep, p) { \
143: (ndp)->ni_cnd.cn_nameiop = op; \
144: (ndp)->ni_cnd.cn_flags = flags; \
145: (ndp)->ni_segflg = segflg; \
146: (ndp)->ni_dirp = namep; \
147: (ndp)->ni_cnd.cn_proc = p; \
148: }
149: #endif
150:
151: /*
152: * This structure describes the elements in the cache of recent
153: * names looked up by namei. NCHNAMLEN is sized to make structure
154: * size a power of two to optimize malloc's. Minimum reasonable
155: * size is 15.
156: */
157:
158: #define NCHNAMLEN 31 /* maximum name segment length we bother with */
159:
160: struct namecache {
161: LIST_ENTRY(namecache) nc_hash; /* hash chain */
162: LIST_ENTRY(namecache) nc_vhash; /* (reverse) directory hash chain */
163: TAILQ_ENTRY(namecache) nc_lru; /* LRU chain */
164: struct vnode *nc_dvp; /* vnode of parent of name */
165: u_long nc_dvpid; /* capability number of nc_dvp */
166: struct vnode *nc_vp; /* vnode the name refers to */
167: u_long nc_vpid; /* capability number of nc_vp */
168: char nc_nlen; /* length of name */
169: char nc_name[NCHNAMLEN]; /* segment name */
170: };
171:
172: #ifdef _KERNEL
173: int namei(struct nameidata *ndp);
174: int lookup(struct nameidata *ndp);
175: int relookup(struct vnode *dvp, struct vnode **vpp,
176: struct componentname *cnp);
177: void cache_purge(struct vnode *);
178: int cache_lookup(struct vnode *, struct vnode **, struct componentname *);
179: void cache_enter(struct vnode *, struct vnode *, struct componentname *);
180: int cache_revlookup(struct vnode *, struct vnode **, char **, char *);
181: void nchinit(void);
182: struct mount;
183: void cache_purgevfs(struct mount *);
184:
185: extern struct pool namei_pool;
186:
187: #endif
188:
189: /*
190: * Stats on usefulness of namei caches.
191: */
192: struct nchstats {
193: long ncs_goodhits; /* hits that we can really use */
194: long ncs_neghits; /* negative hits that we can use */
195: long ncs_badhits; /* hits we must drop */
196: long ncs_falsehits; /* hits with id mismatch */
197: long ncs_miss; /* misses */
198: long ncs_long; /* long names that ignore cache */
199: long ncs_pass2; /* names found with passes == 2 */
200: long ncs_2passes; /* number of times we attempt it */
201: long ncs_revhits; /* reverse-cache hits */
202: long ncs_revmiss; /* reverse-cache misses */
203: };
204:
205: /* These sysctl names are only really used by sysctl(8) */
206: #define KERN_NCHSTATS_GOODHITS 1
207: #define KERN_NCHSTATS_NEGHITS 2
208: #define KERN_NCHSTATS_BADHITS 3
209: #define KERN_NCHSTATS_FALSEHITS 4
210: #define KERN_NCHSTATS_MISS 5
211: #define KERN_NCHSTATS_LONG 6
212: #define KERN_NCHSTATS_PASS2 7
213: #define KERN_NCHSTATS_2PASSES 8
214: #define KERN_NCHSTATS_REVHITS 9
215: #define KERN_NCHSTATS_REVMISS 10
216: #define KERN_NCHSTATS_MAXID 11
217:
218: #define CTL_KERN_NCHSTATS_NAMES { \
219: { 0, 0 }, \
220: { "good_hits", CTLTYPE_INT }, \
221: { "negative_hits", CTLTYPE_INT }, \
222: { "bad_hits", CTLTYPE_INT }, \
223: { "false_hits", CTLTYPE_INT }, \
224: { "misses", CTLTYPE_INT }, \
225: { "long_names", CTLTYPE_INT }, \
226: { "pass2", CTLTYPE_INT }, \
227: { "2passes", CTLTYPE_INT }, \
228: { "ncs_revhits", CTLTYPE_INT }, \
229: { "ncs_revmiss", CTLTYPE_INT }, \
230: }
231: #endif /* !_SYS_NAMEI_H_ */
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