bsd/sys/namei.h

   1 /*
   2  * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  23 /*
  24  * Copyright (c) 1985, 1989, 1991, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  *
  27  * Redistribution and use in source and binary forms, with or without
  28  * modification, are permitted provided that the following conditions
  29  * are met:
  30  * 1. Redistributions of source code must retain the above copyright
  31  *    notice, this list of conditions and the following disclaimer.
  32  * 2. Redistributions in binary form must reproduce the above copyright
  33  *    notice, this list of conditions and the following disclaimer in the
  34  *    documentation and/or other materials provided with the distribution.
  35  * 3. All advertising materials mentioning features or use of this software
  36  *    must display the following acknowledgement:
  37  *      This product includes software developed by the University of
  38  *      California, Berkeley and its contributors.
  39  * 4. Neither the name of the University nor the names of its contributors
  40  *    may be used to endorse or promote products derived from this software
  41  *    without specific prior written permission.
  42  *
  43  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  44  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  45  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  46  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  47  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  48  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  49  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  50  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  51  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  52  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  53  * SUCH DAMAGE.
  54  *
  55  *      @(#)namei.h     8.4 (Berkeley) 8/20/94
  56  */
  57
  58 #ifndef _SYS_NAMEI_H_
  59 #define _SYS_NAMEI_H_
  60
  61 #include <sys/appleapiopts.h>
  62
  63 #ifdef KERNEL
  64 #define LOCKLEAF        0x0004  /* lock inode on return */
  65 #define LOCKPARENT      0x0008  /* want parent vnode returned */
  66 #define WANTPARENT      0x0010  /* want parent vnode returned */
  67 #endif
  68
  69
  70 #ifdef BSD_KERNEL_PRIVATE
  71
  72 #include <sys/queue.h>
  73 #include <sys/uio.h>
  74 #include <sys/vnode.h>
  75 #include <sys/mount.h>
  76 #include <sys/filedesc.h>
  77
  78 #define PATHBUFLEN      256
  79
  80 /*
  81  * Encapsulation of namei parameters.
  82  */
  83 struct nameidata {
  84         /*
  85          * Arguments to namei/lookup.
  86          */
  87         user_addr_t ni_dirp;            /* pathname pointer */
  88         enum    uio_seg ni_segflg;      /* location of pathname */
  89         /*
  90          * Arguments to lookup.
  91          */
  92         struct  vnode *ni_startdir;     /* starting directory */
  93         struct  vnode *ni_rootdir;      /* logical root directory */
  94         struct  vnode *ni_usedvp;       /* directory passed in via USEDVP */
  95         /*
  96          * Results: returned from/manipulated by lookup
  97          */
  98         struct  vnode *ni_vp;           /* vnode of result */
  99         struct  vnode *ni_dvp;          /* vnode of intermediate directory */
 100         /*
 101          * Shared between namei and lookup/commit routines.
 102          */
 103         u_int   ni_pathlen;             /* remaining chars in path */
 104         char    *ni_next;               /* next location in pathname */
 105         char    ni_pathbuf[PATHBUFLEN];
 106         u_long  ni_loopcnt;             /* count of symlinks encountered */
 107
 108         struct componentname ni_cnd;
 109 };
 110
 111 #ifdef KERNEL
 112 /*
 113  * namei operational modifier flags, stored in ni_cnd.flags
 114  */
 115 #define NOCACHE         0x0020  /* name must not be left in cache */
 116 #define NOFOLLOW        0x0000  /* do not follow symbolic links (pseudo) */
 117 #define SHAREDLEAF      0x0080  /* OK to have shared leaf lock */
 118 #define MODMASK         0x00fc  /* mask of operational modifiers */
 119 /*
 120  * Namei parameter descriptors.
 121  *
 122  * SAVESTART is set only by the callers of namei. It implies SAVENAME
 123  * plus the addition of saving the parent directory that contains the
 124  * name in ni_startdir. It allows repeated calls to lookup for the
 125  * name being sought. The caller is responsible for releasing the
 126  * buffer and for vrele'ing ni_startdir.
 127  */
 128 #define NOCROSSMOUNT    0x00000100 /* do not cross mount points */
 129 #define RDONLY          0x00000200 /* lookup with read-only semantics */
 130 #define HASBUF          0x00000400 /* has allocated pathname buffer */
 131 #define SAVENAME        0x00000800 /* save pathanme buffer */
 132 #define SAVESTART       0x00001000 /* save starting directory */
 133 #define ISSYMLINK       0x00010000 /* symlink needs interpretation */
 134 #define DONOTAUTH       0x00020000 /* do not authorize during lookup */
 135 #define WILLBEDIR       0x00080000 /* new files will be dirs; allow trailing / */
 136 #define AUDITVNPATH1    0x00100000 /* audit the path/vnode info */
 137 #define AUDITVNPATH2    0x00200000 /* audit the path/vnode info */
 138 #define USEDVP          0x00400000 /* start the lookup at ndp.ni_dvp */
 139 #define PARAMASK        0x003fff00 /* mask of parameter descriptors */
 140 #define FSNODELOCKHELD  0x01000000
 141
 142 /*
 143  * Initialization of an nameidata structure.
 144  */
 145 #define NDINIT(ndp, op, flags, segflg, namep, ctx) { \
 146         (ndp)->ni_cnd.cn_nameiop = op; \
 147         (ndp)->ni_cnd.cn_flags = flags; \
 148         if ((segflg) == UIO_USERSPACE) { \
 149                 (ndp)->ni_segflg = ((IS_64BIT_PROCESS(vfs_context_proc(ctx))) ? UIO_USERSPACE64 : UIO_USERSPACE32); \
 150         } \
 151         else if ((segflg) == UIO_SYSSPACE) { \
 152                 (ndp)->ni_segflg = UIO_SYSSPACE32; \
 153         } \
 154         else { \
 155                 (ndp)->ni_segflg = segflg; \
 156         } \
 157         (ndp)->ni_dirp = namep; \
 158         (ndp)->ni_cnd.cn_context = ctx; \
 159 }
 160 #endif /* KERNEL */
 161
 162 /*
 163  * This structure describes the elements in the cache of recent
 164  * names looked up by namei.
 165  */
 166
 167 #define NCHNAMLEN       31      /* maximum name segment length we bother with */
 168 #define NCHASHMASK      0x7fffffff
 169
 170 struct  namecache {
 171         TAILQ_ENTRY(namecache)  nc_entry;       /* chain of all entries */
 172         LIST_ENTRY(namecache)   nc_hash;        /* hash chain */
 173         LIST_ENTRY(namecache)   nc_child;       /* chain of ncp's that are children of a vp */
 174         union {
 175           LIST_ENTRY(namecache)  nc_link;       /* chain of ncp's that 'name' a vp */
 176           TAILQ_ENTRY(namecache) nc_negentry;   /* chain of ncp's that 'name' a vp */
 177         } nc_un;
 178         vnode_t                 nc_dvp;         /* vnode of parent of name */
 179         vnode_t                 nc_vp;          /* vnode the name refers to */
 180         unsigned int            nc_whiteout:1,  /* name has whiteout applied */
 181                                 nc_hashval:31;  /* hashval of stringname */
 182         char            *       nc_name;        /* pointer to segment name in string cache */
 183 };
 184
 185
 186 #ifdef KERNEL
 187
 188 int     namei(struct nameidata *ndp);
 189 void    nameidone(struct nameidata *);
 190 int     lookup(struct nameidata *ndp);
 191 int     relookup(struct vnode *dvp, struct vnode **vpp,
 192                 struct componentname *cnp);
 193
 194 /*
 195  * namecache function prototypes
 196  */
 197 void    cache_purgevfs(mount_t mp);
 198 int             cache_lookup_path(struct nameidata *ndp, struct componentname *cnp, vnode_t dp,
 199                           vfs_context_t context, int *trailing_slash, int *dp_authorized);
 200
 201 void    vnode_cache_credentials(vnode_t vp, vfs_context_t context);
 202 void    vnode_uncache_credentials(vnode_t vp);
 203 int             reverse_lookup(vnode_t start_vp, vnode_t *lookup_vpp,
 204                                 struct filedesc *fdp, vfs_context_t context, int *dp_authorized);
 205
 206 #endif /* KERNEL */
 207
 208 /*
 209  * Stats on usefulness of namei caches.
 210  */
 211 struct  nchstats {
 212         long    ncs_negtotal;
 213         long    ncs_goodhits;           /* hits that we can really use */
 214         long    ncs_neghits;            /* negative hits that we can use */
 215         long    ncs_badhits;            /* hits we must drop */
 216         long    ncs_miss;               /* misses */
 217         long    ncs_pass2;              /* names found with passes == 2 */
 218         long    ncs_2passes;            /* number of times we attempt it */
 219         long    ncs_stolen;
 220         long    ncs_enters;
 221         long    ncs_deletes;
 222         long    ncs_badvid;
 223 };
 224 #endif /* BSD_KERNEL_PRIVATE */
 225
 226 #endif /* !_SYS_NAMEI_H_ */