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namei.src
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namei.src
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/* $NetBSD: namei.src,v 1.50 2020/03/23 18:33:43 ad 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>
#include <sys/mutex.h>
#ifdef _KERNEL
#include <sys/kauth.h>
#include <sys/rwlock.h>
/*
* Abstraction for a single pathname.
*
* This contains both the pathname string and (eventually) all
* metadata that determines how the path is to be interpreted.
* It is an opaque structure; the implementation is in vfs_lookup.c.
*
* To call namei, first set up a pathbuf with pathbuf_create or
* pathbuf_copyin, then do NDINIT(), then call namei, then AFTER THE
* STRUCT NAMEIDATA IS DEAD, call pathbuf_destroy. Don't destroy the
* pathbuf before you've finished using the nameidata, or mysterious
* bad things may happen.
*
* pathbuf_assimilate is like pathbuf_create but assumes ownership of
* the string buffer passed in, which MUST BE of size PATH_MAX and
* have been allocated with PNBUF_GET(). This should only be used when
* absolutely necessary; e.g. nfsd uses it for loading paths from
* mbufs.
*/
struct pathbuf;
struct pathbuf *pathbuf_create(const char *path);
struct pathbuf *pathbuf_assimilate(char *path);
int pathbuf_copyin(const char *userpath, struct pathbuf **ret);
void pathbuf_destroy(struct pathbuf *);
/* get a copy of the (current) path string */
void pathbuf_copystring(const struct pathbuf *, char *buf, size_t maxlen);
/* hold a reference copy of the original path string */
const char *pathbuf_stringcopy_get(struct pathbuf *);
void pathbuf_stringcopy_put(struct pathbuf *, const char *);
// XXX remove this
int pathbuf_maybe_copyin(const char *userpath, enum uio_seg seg, struct pathbuf **ret);
/*
* 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.
*/
uint32_t cn_nameiop; /* namei operation */
uint32_t cn_flags; /* flags to namei */
kauth_cred_t cn_cred; /* credentials */
/*
* Shared between lookup and commit routines.
*/
const char *cn_nameptr; /* pointer to looked up name */
size_t cn_namelen; /* length of looked up comp */
size_t cn_consume; /* chars to consume in lookup */
};
/*
* Encapsulation of namei parameters.
*/
struct nameidata {
/*
* Arguments to namei/lookup.
*/
struct vnode *ni_atdir; /* startup dir, cwd if null */
struct pathbuf *ni_pathbuf; /* pathname container */
char *ni_pnbuf; /* extra pathname buffer ref (XXX) */
/*
* Arguments to lookup.
*/
struct vnode *ni_rootdir; /* logical root directory */
struct vnode *ni_erootdir; /* emulation 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 */
unsigned int 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 ni_cnd;
};
/*
* namei operations
*/
NAMEIFL LOOKUP 0 /* perform name lookup only */
NAMEIFL CREATE 1 /* setup for file creation */
NAMEIFL DELETE 2 /* setup for file deletion */
NAMEIFL RENAME 3 /* setup for file renaming */
NAMEIFL OPMASK 3 /* mask for operation */
/*
* namei operational modifier flags, stored in ni_cnd.cn_flags
*/
NAMEIFL LOCKLEAF 0x00000004 /* lock inode on return */
NAMEIFL LOCKPARENT 0x00000008 /* want parent vnode returned locked */
NAMEIFL TRYEMULROOT 0x00000010 /* try relative to emulation root
first */
NAMEIFL NOCACHE 0x00000020 /* name must not be left in cache */
NAMEIFL FOLLOW 0x00000040 /* follow symbolic links */
NAMEIFL NOFOLLOW 0x00000000 /* do not follow symbolic links
(pseudo) */
NAMEIFL EMULROOTSET 0x00000080 /* emulation root already
in ni_erootdir */
NAMEIFL NOCHROOT 0x01000000 /* no chroot on abs path lookups */
NAMEIFL MODMASK 0x010000fc /* mask of operational modifiers */
/*
* Namei parameter descriptors.
*/
NAMEIFL NOCROSSMOUNT 0x0000100 /* do not cross mount points */
NAMEIFL RDONLY 0x0000200 /* lookup with read-only semantics */
NAMEIFL ISDOTDOT 0x0002000 /* current component name is .. */
NAMEIFL MAKEENTRY 0x0004000 /* entry is to be added to name cache */
NAMEIFL ISLASTCN 0x0008000 /* this is last component of pathname */
NAMEIFL ISWHITEOUT 0x0020000 /* found whiteout */
NAMEIFL DOWHITEOUT 0x0040000 /* do whiteouts */
NAMEIFL REQUIREDIR 0x0080000 /* must be a directory */
NAMEIFL CREATEDIR 0x0200000 /* trailing slashes are ok */
NAMEIFL PARAMASK 0x02ee300 /* mask of parameter descriptors */
/*
* Initialization of a nameidata structure.
*/
#define NDINIT(ndp, op, flags, pathbuf) { \
(ndp)->ni_cnd.cn_nameiop = op; \
(ndp)->ni_cnd.cn_flags = flags; \
(ndp)->ni_atdir = NULL; \
(ndp)->ni_pathbuf = pathbuf; \
(ndp)->ni_cnd.cn_cred = kauth_cred_get(); \
}
/*
* Use this to set the start directory for openat()-type operations.
*/
#define NDAT(ndp, dir) { \
(ndp)->ni_atdir = (dir); \
}
#endif
#ifdef __NAMECACHE_PRIVATE
#include <sys/rbtree.h>
/*
* For simplicity (and economy of storage), names longer than
* a maximum length of NCHNAMLEN are stored in non-pooled storage.
*/
#define NCHNAMLEN sizeof(((struct namecache *)NULL)->nc_name)
/*
* Namecache entry.
*
* This structure describes the elements in the cache of recent names looked
* up by namei. It's carefully sized to take up 128 bytes on _LP64, to make
* good use of space and the CPU caches. Items used during RB tree lookup
* (nc_tree, nc_key) are clustered at the start of the structure.
*
* Field markings and their corresponding locks:
*
* - stable throught the lifetime of the namecache entry
* d protected by nc_dvp->vi_ncdlock
* v protected by nc_dvp->vi_ncvlock
* l protected by cache_lru_lock
* u accesses are unlocked, no serialization applied
*/
struct nchnode;
struct namecache {
struct rb_node nc_tree; /* d red-black tree, must be first */
uint64_t nc_key; /* - hash key */
TAILQ_ENTRY(namecache) nc_list; /* v vp's list of cache entries */
TAILQ_ENTRY(namecache) nc_lru; /* l pseudo-lru chain */
struct vnode *nc_dvp; /* - vnode of parent of name */
struct vnode *nc_vp; /* - vnode the name refers to */
int nc_lrulist; /* l which LRU list its on */
u_short nc_nlen; /* - length of the name */
char nc_whiteout; /* - true if a whiteout */
char nc_name[41]; /* - segment name */
};
#endif
#ifdef _KERNEL
#include <sys/pool.h>
struct mount;
struct cpu_info;
extern pool_cache_t pnbuf_cache; /* pathname buffer cache */
#define PNBUF_GET() ((char *)pool_cache_get(pnbuf_cache, PR_WAITOK))
#define PNBUF_PUT(pnb) pool_cache_put(pnbuf_cache, (void *)(pnb))
/*
* Typesafe flags for namei_simple/nameiat_simple.
*
* This encoding is not optimal but serves the important purpose of
* not being type-compatible with the regular namei flags.
*/
struct namei_simple_flags_type; /* Opaque. */
typedef const struct namei_simple_flags_type *namei_simple_flags_t; /* Gross. */
extern const namei_simple_flags_t
NSM_NOFOLLOW_NOEMULROOT,
NSM_NOFOLLOW_TRYEMULROOT,
NSM_FOLLOW_NOEMULROOT,
NSM_FOLLOW_TRYEMULROOT;
/*
* namei(at)?_simple_* - the simple cases of namei, with no struct
* nameidata involved.
*
* namei_simple_kernel takes a kernel-space path as the first argument.
* namei_simple_user takes a user-space path as the first argument.
* The nameiat_simple_* variants handle relative path using the given
* directory vnode instead of current directory.
*
* A namei call can be converted to namei_simple_* if:
* - the second arg to NDINIT is LOOKUP;
* - it does not need the parent vnode, nd.ni_dvp;
* - the only flags it uses are (NO)FOLLOW and TRYEMULROOT;
* - it does not do anything else gross with the contents of nd.
*/
int namei_simple_kernel(const char *, namei_simple_flags_t, struct vnode **);
int namei_simple_user(const char *, namei_simple_flags_t, struct vnode **);
int nameiat_simple_kernel(struct vnode *, const char *, namei_simple_flags_t,
struct vnode **);
int nameiat_simple_user(struct vnode *, const char *, namei_simple_flags_t,
struct vnode **);
int namei(struct nameidata *);
uint32_t namei_hash(const char *, const char **);
int lookup_for_nfsd(struct nameidata *, struct vnode *, int neverfollow);
int lookup_for_nfsd_index(struct nameidata *, struct vnode *);
int relookup(struct vnode *, struct vnode **, struct componentname *, int);
void cache_purge1(struct vnode *, const char *, size_t, int);
#define PURGE_PARENTS 1
#define PURGE_CHILDREN 2
#define cache_purge(vp) cache_purge1((vp),NULL,0,PURGE_PARENTS|PURGE_CHILDREN)
bool cache_lookup(struct vnode *, const char *, size_t, uint32_t, uint32_t,
int *, struct vnode **);
bool cache_lookup_raw(struct vnode *, const char *, size_t, uint32_t,
int *, struct vnode **);
bool cache_lookup_linked(struct vnode *, const char *, size_t,
struct vnode **, krwlock_t **, kauth_cred_t);
int cache_revlookup(struct vnode *, struct vnode **, char **, char *,
bool, int);
int cache_diraccess(struct vnode *, int);
void cache_enter(struct vnode *, struct vnode *,
const char *, size_t, uint32_t);
void cache_enter_id(struct vnode *, mode_t, uid_t, gid_t);
bool cache_have_id(struct vnode *);
void cache_vnode_init(struct vnode * );
void cache_vnode_fini(struct vnode * );
void cache_cpu_init(struct cpu_info *);
void nchinit(void);
void namecache_count_pass2(void);
void namecache_count_2passes(void);
void cache_purgevfs(struct mount *);
void namecache_print(struct vnode *, void (*)(const char *, ...)
__printflike(1, 2));
#endif
/*
* Stats on usefulness of namei caches. A couple of structures are
* used for counting, with members having the same names but different
* types. Containerize member names with the preprocessor to avoid
* cut-'n'-paste. A (U) in the comment documents values that are
* incremented unlocked; we may treat these specially.
*/
#define _NAMEI_CACHE_STATS(type) { \
type ncs_goodhits; /* hits that we can really use (U) */ \
type ncs_neghits; /* negative hits that we can use */ \
type ncs_badhits; /* hits we must drop */ \
type ncs_falsehits; /* hits with id mismatch (U) */ \
type ncs_miss; /* misses */ \
type ncs_long; /* long names that ignore cache */ \
type ncs_pass2; /* names found with passes == 2 (U) */ \
type ncs_2passes; /* number of times we attempt it (U) */ \
type ncs_revhits; /* reverse-cache hits */ \
type ncs_revmiss; /* reverse-cache misses */ \
type ncs_collisions; /* hash value collisions */ \
type ncs_denied; /* access denied */ \
}
/*
* Sysctl deals with a uint64_t version of the stats and summary
* totals are kept that way.
*/
struct nchstats _NAMEI_CACHE_STATS(uint64_t);
/* #endif !_SYS_NAMEI_H_ (generated by gennameih.awk) */