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namei.h
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namei.h
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/* $NetBSD: namei.h,v 1.45.8.2 2007/02/17 23:27:51 tron Exp $ */
/*
* Copyright (c) 1985, 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)namei.h 8.5 (Berkeley) 8/20/94
*/
#ifndef _SYS_NAMEI_H_
#define _SYS_NAMEI_H_
#include <sys/queue.h>
#ifdef _KERNEL
/*
* Encapsulation of namei parameters.
*/
struct nameidata {
/*
* Arguments to namei/lookup.
*/
const char *ni_dirp; /* pathname pointer */
enum uio_seg ni_segflg; /* location of pathname */
/* u_long ni_nameiop; namei operation */
/* u_long ni_flags; flags to namei */
/* struct proc *ni_proc; process requesting lookup */
/*
* Arguments to lookup.
*/
/* kauth_cred_t ni_cred; credentials */
struct vnode *ni_startdir; /* starting directory */
struct vnode *ni_rootdir; /* logical root directory */
/*
* Results: returned from/manipulated by lookup
*/
struct vnode *ni_vp; /* vnode of result */
struct vnode *ni_dvp; /* vnode of intermediate directory */
/*
* Shared between namei and lookup/commit routines.
*/
size_t ni_pathlen; /* remaining chars in path */
const char *ni_next; /* next location in pathname */
u_long ni_loopcnt; /* count of symlinks encountered */
/*
* Lookup parameters: this structure describes the subset of
* information from the nameidata structure that is passed
* through the VOP interface.
*/
struct componentname {
/*
* Arguments to lookup.
*/
u_long cn_nameiop; /* namei operation */
u_long cn_flags; /* flags to namei */
struct lwp *cn_lwp; /* lwp requesting lookup */
kauth_cred_t cn_cred; /* credentials */
/*
* Shared between lookup and commit routines.
*/
char *cn_pnbuf; /* pathname buffer */
const char *cn_nameptr; /* pointer to looked up name */
long cn_namelen; /* length of looked up component */
u_long cn_hash; /* hash value of looked up name */
long cn_consume; /* chars to consume in lookup() */
} ni_cnd;
};
/*
* namei operations
*/
#define LOOKUP 0 /* perform name lookup only */
#define CREATE 1 /* setup for file creation */
#define DELETE 2 /* setup for file deletion */
#define RENAME 3 /* setup for file renaming */
#define OPMASK 3 /* mask for operation */
/*
* namei operational modifier flags, stored in ni_cnd.cn_flags
*/
#define LOCKLEAF 0x0004 /* lock inode on return */
#define LOCKPARENT 0x0008 /* want parent vnode returned locked */
#define NOCACHE 0x0020 /* name must not be left in cache */
#define FOLLOW 0x0040 /* follow symbolic links */
#define NOFOLLOW 0x0000 /* do not follow symbolic links (pseudo) */
#define MODMASK 0x00fc /* mask of operational modifiers */
/*
* Namei parameter descriptors.
*
* SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
* If the caller of namei sets the flag (for example execve wants to
* know the name of the program that is being executed), then it must
* free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
* be freed by either the commit routine or the VOP_ABORT routine.
* SAVESTART is set only by the callers of namei. It implies SAVENAME
* plus the addition of saving the parent directory that contains the
* name in ni_startdir. It allows repeated calls to lookup for the
* name being sought. The caller is responsible for releasing the
* buffer and for vrele'ing ni_startdir.
*/
#define NOCROSSMOUNT 0x0000100 /* do not cross mount points */
#define RDONLY 0x0000200 /* lookup with read-only semantics */
#define HASBUF 0x0000400 /* has allocated pathname buffer */
#define SAVENAME 0x0000800 /* save pathname buffer */
#define SAVESTART 0x0001000 /* save starting directory */
#define ISDOTDOT 0x0002000 /* current component name is .. */
#define MAKEENTRY 0x0004000 /* entry is to be added to name cache */
#define ISLASTCN 0x0008000 /* this is last component of pathname */
#define ISSYMLINK 0x0010000 /* symlink needs interpretation */
#define ISWHITEOUT 0x0020000 /* found whiteout */
#define DOWHITEOUT 0x0040000 /* do whiteouts */
#define REQUIREDIR 0x0080000 /* must be a directory */
#define CREATEDIR 0x0200000 /* trailing slashes are ok */
#define PARAMASK 0x03fff00 /* mask of parameter descriptors */
/*
* Initialization of an nameidata structure.
*/
#define NDINIT(ndp, op, flags, segflg, namep, l) { \
(ndp)->ni_cnd.cn_nameiop = op; \
(ndp)->ni_cnd.cn_flags = flags; \
(ndp)->ni_segflg = segflg; \
(ndp)->ni_dirp = namep; \
(ndp)->ni_cnd.cn_lwp = l; \
(ndp)->ni_cnd.cn_cred = l->l_cred; \
}
#endif
/*
* This structure describes the elements in the cache of recent
* names looked up by namei. NCHNAMLEN is sized to make structure
* size a power of two to optimize malloc's. Minimum reasonable
* size is 15.
*/
#define NCHNAMLEN 31 /* maximum name segment length we bother with */
struct namecache {
LIST_ENTRY(namecache) nc_hash; /* hash chain */
TAILQ_ENTRY(namecache) nc_lru; /* LRU chain */
LIST_ENTRY(namecache) nc_vhash; /* directory hash chain */
LIST_ENTRY(namecache) nc_dvlist;
struct vnode *nc_dvp; /* vnode of parent of name */
LIST_ENTRY(namecache) nc_vlist;
struct vnode *nc_vp; /* vnode the name refers to */
int nc_flags; /* copy of componentname's ISWHITEOUT */
char nc_nlen; /* length of name */
char nc_name[NCHNAMLEN]; /* segment name */
};
#ifdef _KERNEL
#include <sys/mallocvar.h>
#include <sys/pool.h>
struct mount;
extern struct pool pnbuf_pool; /* pathname buffer pool */
extern struct pool_cache pnbuf_cache; /* pathname buffer cache */
#define PNBUF_GET() pool_cache_get(&pnbuf_cache, PR_WAITOK)
#define PNBUF_PUT(pnb) pool_cache_put(&pnbuf_cache, (pnb))
typedef struct pathname_internal *pathname_t;
int namei(struct nameidata *);
uint32_t namei_hash(const char *, const char **);
int lookup(struct nameidata *);
int relookup(struct vnode *, struct vnode **, struct componentname *);
void cache_purge1(struct vnode *, const struct componentname *, int);
#define PURGE_PARENTS 1
#define PURGE_CHILDREN 2
#define cache_purge(vp) cache_purge1((vp), NULL, PURGE_PARENTS|PURGE_CHILDREN)
int cache_lookup(struct vnode *, struct vnode **, struct componentname *);
int cache_lookup_raw(struct vnode *, struct vnode **,
struct componentname *);
int cache_revlookup(struct vnode *, struct vnode **, char **, char *);
void cache_enter(struct vnode *, struct vnode *, struct componentname *);
void nchinit(void);
void nchreinit(void);
void cache_purgevfs(struct mount *);
void namecache_print(struct vnode *, void (*)(const char *, ...));
int pathname_get(const char *, enum uio_seg, pathname_t *);
const char *pathname_path(pathname_t);
void pathname_put(pathname_t);
#endif
/*
* Stats on usefulness of namei caches.
* XXX: should be 64-bit counters.
*/
struct nchstats {
long ncs_goodhits; /* hits that we can really use */
long ncs_neghits; /* negative hits that we can use */
long ncs_badhits; /* hits we must drop */
long ncs_falsehits; /* hits with id mismatch */
long ncs_miss; /* misses */
long ncs_long; /* long names that ignore cache */
long ncs_pass2; /* names found with passes == 2 */
long ncs_2passes; /* number of times we attempt it */
long ncs_revhits; /* reverse-cache hits */
long ncs_revmiss; /* reverse-cache misses */
};
#ifdef _KERNEL
extern struct nchstats nchstats;
#endif
#endif /* !_SYS_NAMEI_H_ */