Annotation of sys/sys/namei.h, Revision 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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