bsd/sys/namei.h

   1 /*
   2  * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  31 /*
  32  * Copyright (c) 1985, 1989, 1991, 1993
  33  *      The Regents of the University of California.  All rights reserved.
  34  *
  35  * Redistribution and use in source and binary forms, with or without
  36  * modification, are permitted provided that the following conditions
  37  * are met:
  38  * 1. Redistributions of source code must retain the above copyright
  39  *    notice, this list of conditions and the following disclaimer.
  40  * 2. Redistributions in binary form must reproduce the above copyright
  41  *    notice, this list of conditions and the following disclaimer in the
  42  *    documentation and/or other materials provided with the distribution.
  43  * 3. All advertising materials mentioning features or use of this software
  44  *    must display the following acknowledgement:
  45  *      This product includes software developed by the University of
  46  *      California, Berkeley and its contributors.
  47  * 4. Neither the name of the University nor the names of its contributors
  48  *    may be used to endorse or promote products derived from this software
  49  *    without specific prior written permission.
  50  *
  51  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  52  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  53  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  54  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  55  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  56  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  57  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  58  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  59  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  60  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  61  * SUCH DAMAGE.
  62  *
  63  *      @(#)namei.h     8.4 (Berkeley) 8/20/94
  64  */
  65
  66 #ifndef _SYS_NAMEI_H_
  67 #define _SYS_NAMEI_H_
  68
  69 #include <sys/appleapiopts.h>
  70
  71 #ifdef KERNEL
  72 #define LOCKLEAF        0x0004  /* lock inode on return */
  73 #define LOCKPARENT      0x0008  /* want parent vnode returned */
  74 #define WANTPARENT      0x0010  /* want parent vnode returned */
  75 #endif
  76
  77
  78 #ifdef BSD_KERNEL_PRIVATE
  79
  80 #include <sys/queue.h>
  81 #include <sys/uio.h>
  82 #include <sys/vnode.h>
  83 #include <sys/mount.h>
  84 #include <sys/filedesc.h>
  85
  86 #define PATHBUFLEN      256
  87
  88 /*
  89  * Encapsulation of namei parameters.
  90  */
  91 struct nameidata {
  92         /*
  93          * Arguments to namei/lookup.
  94          */
  95         user_addr_t ni_dirp;            /* pathname pointer */
  96         enum    uio_seg ni_segflg;      /* location of pathname */
  97         /*
  98          * Arguments to lookup.
  99          */
 100         struct  vnode *ni_startdir;     /* starting directory */
 101         struct  vnode *ni_rootdir;      /* logical root directory */
 102         struct  vnode *ni_usedvp;       /* directory passed in via USEDVP */
 103         /*
 104          * Results: returned from/manipulated by lookup
 105          */
 106         struct  vnode *ni_vp;           /* vnode of result */
 107         struct  vnode *ni_dvp;          /* vnode of intermediate directory */
 108         /*
 109          * Shared between namei and lookup/commit routines.
 110          */
 111         u_int   ni_pathlen;             /* remaining chars in path */
 112         char    *ni_next;               /* next location in pathname */
 113         char    ni_pathbuf[PATHBUFLEN];
 114         u_long  ni_loopcnt;             /* count of symlinks encountered */
 115
 116         struct componentname ni_cnd;
 117 };
 118
 119 #ifdef KERNEL
 120 /*
 121  * namei operational modifier flags, stored in ni_cnd.flags
 122  */
 123 #define NOCACHE         0x0020  /* name must not be left in cache */
 124 #define NOFOLLOW        0x0000  /* do not follow symbolic links (pseudo) */
 125 #define SHAREDLEAF      0x0080  /* OK to have shared leaf lock */
 126 #define MODMASK         0x00fc  /* mask of operational modifiers */
 127 /*
 128  * Namei parameter descriptors.
 129  *
 130  * SAVESTART is set only by the callers of namei. It implies SAVENAME
 131  * plus the addition of saving the parent directory that contains the
 132  * name in ni_startdir. It allows repeated calls to lookup for the
 133  * name being sought. The caller is responsible for releasing the
 134  * buffer and for vrele'ing ni_startdir.
 135  */
 136 #define NOCROSSMOUNT    0x00000100 /* do not cross mount points */
 137 #define RDONLY          0x00000200 /* lookup with read-only semantics */
 138 #define HASBUF          0x00000400 /* has allocated pathname buffer */
 139 #define SAVENAME        0x00000800 /* save pathanme buffer */
 140 #define SAVESTART       0x00001000 /* save starting directory */
 141 #define ISSYMLINK       0x00010000 /* symlink needs interpretation */
 142 #define DONOTAUTH       0x00020000 /* do not authorize during lookup */
 143 #define WILLBEDIR       0x00080000 /* new files will be dirs; allow trailing / */
 144 #define AUDITVNPATH1    0x00100000 /* audit the path/vnode info */
 145 #define AUDITVNPATH2    0x00200000 /* audit the path/vnode info */
 146 #define USEDVP          0x00400000 /* start the lookup at ndp.ni_dvp */
 147 #define PARAMASK        0x003fff00 /* mask of parameter descriptors */
 148 #define FSNODELOCKHELD  0x01000000
 149
 150 /*
 151  * Initialization of an nameidata structure.
 152  */
 153 #define NDINIT(ndp, op, flags, segflg, namep, ctx) { \
 154         (ndp)->ni_cnd.cn_nameiop = op; \
 155         (ndp)->ni_cnd.cn_flags = flags; \
 156         if ((segflg) == UIO_USERSPACE) { \
 157                 (ndp)->ni_segflg = ((IS_64BIT_PROCESS(vfs_context_proc(ctx))) ? UIO_USERSPACE64 : UIO_USERSPACE32); \
 158         } \
 159         else if ((segflg) == UIO_SYSSPACE) { \
 160                 (ndp)->ni_segflg = UIO_SYSSPACE32; \
 161         } \
 162         else { \
 163                 (ndp)->ni_segflg = segflg; \
 164         } \
 165         (ndp)->ni_dirp = namep; \
 166         (ndp)->ni_cnd.cn_context = ctx; \
 167 }
 168 #endif /* KERNEL */
 169
 170 /*
 171  * This structure describes the elements in the cache of recent
 172  * names looked up by namei.
 173  */
 174
 175 #define NCHNAMLEN       31      /* maximum name segment length we bother with */
 176 #define NCHASHMASK      0x7fffffff
 177
 178 struct  namecache {
 179         TAILQ_ENTRY(namecache)  nc_entry;       /* chain of all entries */
 180         LIST_ENTRY(namecache)   nc_hash;        /* hash chain */
 181         LIST_ENTRY(namecache)   nc_child;       /* chain of ncp's that are children of a vp */
 182         union {
 183           LIST_ENTRY(namecache)  nc_link;       /* chain of ncp's that 'name' a vp */
 184           TAILQ_ENTRY(namecache) nc_negentry;   /* chain of ncp's that 'name' a vp */
 185         } nc_un;
 186         vnode_t                 nc_dvp;         /* vnode of parent of name */
 187         vnode_t                 nc_vp;          /* vnode the name refers to */
 188         unsigned int            nc_whiteout:1,  /* name has whiteout applied */
 189                                 nc_hashval:31;  /* hashval of stringname */
 190         char            *       nc_name;        /* pointer to segment name in string cache */
 191 };
 192
 193
 194 #ifdef KERNEL
 195
 196 int     namei(struct nameidata *ndp);
 197 void    nameidone(struct nameidata *);
 198 int     lookup(struct nameidata *ndp);
 199 int     relookup(struct vnode *dvp, struct vnode **vpp,
 200                 struct componentname *cnp);
 201
 202 /*
 203  * namecache function prototypes
 204  */
 205 void    cache_purgevfs(mount_t mp);
 206 int             cache_lookup_path(struct nameidata *ndp, struct componentname *cnp, vnode_t dp,
 207                           vfs_context_t context, int *trailing_slash, int *dp_authorized);
 208
 209 void    vnode_cache_credentials(vnode_t vp, vfs_context_t context);
 210 void    vnode_uncache_credentials(vnode_t vp);
 211 int             reverse_lookup(vnode_t start_vp, vnode_t *lookup_vpp,
 212                                 struct filedesc *fdp, vfs_context_t context, int *dp_authorized);
 213
 214 #endif /* KERNEL */
 215
 216 /*
 217  * Stats on usefulness of namei caches.
 218  */
 219 struct  nchstats {
 220         long    ncs_goodhits;           /* hits that we can really use */
 221         long    ncs_neghits;            /* negative hits that we can use */
 222         long    ncs_badhits;            /* hits we must drop */
 223         long    ncs_miss;               /* misses */
 224         long    ncs_pass2;              /* names found with passes == 2 */
 225         long    ncs_2passes;            /* number of times we attempt it */
 226         long    ncs_stolen;
 227         long    ncs_enters;
 228         long    ncs_deletes;
 229         long    ncs_badvid;
 230 };
 231 #endif /* BSD_KERNEL_PRIVATE */
 232
 233 #endif /* !_SYS_NAMEI_H_ */