bsd/sys/namei.h

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