4.3BSD-Reno/src/sys/sys/namei.h

/*
 * Copyright (c) 1985, 1989 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution is only permitted until one year after the first shipment
 * of 4.4BSD by the Regents.  Otherwise, redistribution and use in source and
 * binary forms are permitted provided that: (1) source distributions retain
 * this entire copyright notice and comment, and (2) distributions including
 * binaries display the following acknowledgement:  This product includes
 * software developed by the University of California, Berkeley and its
 * contributors'' in the documentation or other materials provided with the
 * distribution and in all advertising materials mentioning features or use
 * of this software.  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 AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *	@(#)namei.h	7.10 (Berkeley) 6/28/90
 */

#ifndef _NAMEI_
#define	_NAMEI_

#ifdef KERNEL
#include "../ufs/dir.h"
#include "uio.h"
#else
#include <sys/uio.h>
#include <ufs/dir.h>
#endif

/*
 * Encapsulation of namei parameters.
 * One of these is located in the u. area to
 * minimize space allocated on the kernel stack.
 */
struct nameidata {
		/* arguments to namei and related context: */
	caddr_t	ni_dirp;		/* pathname pointer */
	enum	uio_seg ni_segflg;	/* location of pathname */
	short	ni_nameiop;		/* see below */
	struct	vnode *ni_cdir;		/* current directory */
	struct	vnode *ni_rdir;		/* root directory, if not normal root */
	struct	ucred *ni_cred;		/* credentials */

		/* shared between namei, lookup routines and commit routines: */
	caddr_t	ni_pnbuf;		/* pathname buffer */
	char	*ni_ptr;		/* current location in pathname */
	char	*ni_next;		/* next location in pathname */
	u_int	ni_pathlen;		/* remaining chars in path */
	u_long	ni_hash;		/* hash value of current component */
	short	ni_namelen;		/* length of current component */
	short	ni_loopcnt;		/* count of symlinks encountered */
	char	ni_makeentry;		/* 1 => add entry to name cache */
	char	ni_isdotdot;		/* 1 => current component name is .. */

		/* results: */
	struct	vnode *ni_vp;		/* vnode of result */
	struct	vnode *ni_dvp;		/* vnode of intermediate directory */
	struct	direct ni_dent;		/* final component name */

		/* side effects: */
	/* BEGIN UFS SPECIFIC */
	off_t	ni_endoff;		/* end of useful directory contents */
	struct ndirinfo {		/* saved info for new dir entry */
		struct	iovec nd_iovec;		/* pointed to by ni_iov */
		struct	uio nd_uio;		/* directory I/O parameters */
	} ni_nd;
	/* END UFS SPECIFIC */
};

#define	ni_base		ni_nd.nd_iovec.iov_base
#define	ni_count	ni_nd.nd_iovec.iov_len
#define	ni_uioseg	ni_nd.nd_uio.uio_segflg
#define	ni_iov		ni_nd.nd_uio.uio_iov
#define	ni_iovcnt	ni_nd.nd_uio.uio_iovcnt
#define	ni_offset	ni_nd.nd_uio.uio_offset
#define	ni_resid	ni_nd.nd_uio.uio_resid
#define	ni_rw		ni_nd.nd_uio.uio_rw
#define	ni_uio		ni_nd.nd_uio

#ifdef KERNEL
/*
 * namei operations and modifiers
 */
#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	OPFLAG		3	/* mask for operation */
#define	LOCKLEAF	0x004	/* lock inode on return */
#define	LOCKPARENT	0x008	/* want parent vnode returned locked */
#define	WANTPARENT	0x010	/* want parent vnode returned unlocked */
#define	NOCACHE		0x020	/* name must not be left in cache */
#define	FOLLOW		0x040	/* follow symbolic links */
#define	NOFOLLOW	0x000	/* do not follow symbolic links (pseudo) */
#define	NOCROSSMOUNT	0x080	/* do not cross mount points */
#define	REMOTE		0x100	/* lookup for remote filesystem servers */
#define	HASBUF		0x200	/* has preallocated pathname buffer */
#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 {
	struct	namecache *nc_forw;	/* hash chain, MUST BE FIRST */
	struct	namecache *nc_back;	/* hash chain, MUST BE FIRST */
	struct	namecache *nc_nxt;	/* LRU chain */
	struct	namecache **nc_prev;	/* LRU chain */
	struct	vnode *nc_dvp;		/* vnode of parent of name */
	u_long	nc_dvpid;		/* capability number of nc_dvp */
	struct	vnode *nc_vp;		/* vnode the name refers to */
	u_long	nc_vpid;		/* capability number of nc_vp */
	char	nc_nlen;		/* length of name */
	char	nc_name[NCHNAMLEN];	/* segment name */
};

#ifdef KERNEL
u_long	nextvnodeid;
#endif

/*
 * Stats on usefulness of namei caches.
 */
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 */
};
#endif /* _NAMEI_ */