bsd/sys/namei.h

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  26 /*
  27  * Copyright (c) 1985, 1989, 1991, 1993
  28  *      The Regents of the University of California.  All rights reserved.
  29  *
  30  * Redistribution and use in source and binary forms, with or without
  31  * modification, are permitted provided that the following conditions
  32  * are met:
  33  * 1. Redistributions of source code must retain the above copyright
  34  *    notice, this list of conditions and the following disclaimer.
  35  * 2. Redistributions in binary form must reproduce the above copyright
  36  *    notice, this list of conditions and the following disclaimer in the
  37  *    documentation and/or other materials provided with the distribution.
  38  * 3. All advertising materials mentioning features or use of this software
  39  *    must display the following acknowledgement:
  40  *      This product includes software developed by the University of
  41  *      California, Berkeley and its contributors.
  42  * 4. Neither the name of the University nor the names of its contributors
  43  *    may be used to endorse or promote products derived from this software
  44  *    without specific prior written permission.
  45  *
  46  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  56  * SUCH DAMAGE.
  57  *
  58  *      @(#)namei.h     8.4 (Berkeley) 8/20/94
  59  */
  60
  61 #ifndef _SYS_NAMEI_H_
  62 #define _SYS_NAMEI_H_
  63
  64 #include <sys/appleapiopts.h>
  65
  66 #ifdef __APPLE_API_UNSTABLE
  67
  68 #include <sys/queue.h>
  69 #include <sys/uio.h>
  70
  71 /*
  72  * Lookup parameters: this structure describes the subset of
  73  * information from the nameidata structure that is passed
  74  * through the VOP interface.
  75  */
  76 struct componentname {
  77         /*
  78          * Arguments to lookup.
  79          */
  80         u_long  cn_nameiop;     /* namei operation */
  81         u_long  cn_flags;       /* flags to namei */
  82         struct  proc *cn_proc;  /* process requesting lookup */
  83         struct  ucred *cn_cred; /* credentials */
  84         /*
  85          * Shared between lookup and commit routines.
  86          */
  87         char    *cn_pnbuf;      /* pathname buffer */
  88         long    cn_pnlen;       /* length of allocated buffer */
  89         char    *cn_nameptr;    /* pointer to looked up name */
  90         long    cn_namelen;     /* length of looked up component */
  91         u_long  cn_hash;        /* hash value of looked up name */
  92         long    cn_consume;     /* chars to consume in lookup() */
  93 };
  94
  95 /*
  96  * Encapsulation of namei parameters.
  97  */
  98 struct nameidata {
  99         /*
 100          * Arguments to namei/lookup.
 101          */
 102         caddr_t ni_dirp;                /* pathname pointer */
 103         enum    uio_seg ni_segflg;      /* location of pathname */
 104      /* u_long  ni_nameiop;                namei operation */
 105      /* u_long  ni_flags;                  flags to namei */
 106      /* struct  proc *ni_proc;             process requesting lookup */
 107         /*
 108          * Arguments to lookup.
 109          */
 110      /* struct  ucred *ni_cred;            credentials */
 111         struct  vnode *ni_startdir;     /* starting directory */
 112         struct  vnode *ni_rootdir;      /* logical root directory */
 113         /*
 114          * Results: returned from/manipulated by lookup
 115          */
 116         struct  vnode *ni_vp;           /* vnode of result */
 117         struct  vnode *ni_dvp;          /* vnode of intermediate directory */
 118         /*
 119          * Shared between namei and lookup/commit routines.
 120          */
 121         u_int   ni_pathlen;             /* remaining chars in path */
 122         char    *ni_next;               /* next location in pathname */
 123         u_long  ni_loopcnt;             /* count of symlinks encountered */
 124         struct componentname ni_cnd;
 125 };
 126
 127 #ifdef KERNEL
 128 /*
 129  * namei operations
 130  */
 131 #define LOOKUP          0       /* perform name lookup only */
 132 #define CREATE          1       /* setup for file creation */
 133 #define DELETE          2       /* setup for file deletion */
 134 #define RENAME          3       /* setup for file renaming */
 135 #define OPMASK          3       /* mask for operation */
 136 /*
 137  * namei operational modifier flags, stored in ni_cnd.flags
 138  */
 139 #define LOCKLEAF        0x0004  /* lock inode on return */
 140 #define LOCKPARENT      0x0008  /* want parent vnode returned locked */
 141 #define WANTPARENT      0x0010  /* want parent vnode returned unlocked */
 142 #define NOCACHE         0x0020  /* name must not be left in cache */
 143 #define FOLLOW          0x0040  /* follow symbolic links */
 144 #define NOFOLLOW        0x0000  /* do not follow symbolic links (pseudo) */
 145 #define MODMASK         0x00fc  /* mask of operational modifiers */
 146 /*
 147  * Namei parameter descriptors.
 148  *
 149  * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
 150  * If the caller of namei sets the flag (for example execve wants to
 151  * know the name of the program that is being executed), then it must
 152  * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
 153  * be freed by either the commit routine or the VOP_ABORT routine.
 154  * SAVESTART is set only by the callers of namei. It implies SAVENAME
 155  * plus the addition of saving the parent directory that contains the
 156  * name in ni_startdir. It allows repeated calls to lookup for the
 157  * name being sought. The caller is responsible for releasing the
 158  * buffer and for vrele'ing ni_startdir.
 159  */
 160 #define NOCROSSMOUNT    0x000100 /* do not cross mount points */
 161 #define RDONLY          0x000200 /* lookup with read-only semantics */
 162 #define HASBUF          0x000400 /* has allocated pathname buffer */
 163 #define SAVENAME        0x000800 /* save pathanme buffer */
 164 #define SAVESTART       0x001000 /* save starting directory */
 165 #define ISDOTDOT        0x002000 /* current component name is .. */
 166 #define MAKEENTRY       0x004000 /* entry is to be added to name cache */
 167 #define ISLASTCN        0x008000 /* this is last component of pathname */
 168 #define ISSYMLINK       0x010000 /* symlink needs interpretation */
 169 #define ISWHITEOUT      0x020000 /* found whiteout */
 170 #define DOWHITEOUT      0x040000 /* do whiteouts */
 171 #define WILLBEDIR       0x080000 /* new files will be dirs; allow trailing / */
 172 #define NODELETEBUSY    0x800000 /* donot delete busy files (Carbon semantic) */
 173 #define PARAMASK        0x0fff00 /* mask of parameter descriptors */
 174 /*
 175  * Initialization of an nameidata structure.
 176  */
 177 #define NDINIT(ndp, op, flags, segflg, namep, p) { \
 178         (ndp)->ni_cnd.cn_nameiop = op; \
 179         (ndp)->ni_cnd.cn_flags = flags; \
 180         (ndp)->ni_segflg = segflg; \
 181         (ndp)->ni_dirp = namep; \
 182         (ndp)->ni_cnd.cn_proc = p; \
 183 }
 184 #endif /* KERNEL */
 185
 186 /*
 187  * This structure describes the elements in the cache of recent
 188  * names looked up by namei. NCHNAMLEN is sized to make structure
 189  * size a power of two to optimize malloc's. Minimum reasonable
 190  * size is 15.
 191  */
 192
 193 #define NCHNAMLEN       31      /* maximum name segment length we bother with */
 194
 195 struct  namecache {
 196         LIST_ENTRY(namecache) nc_hash;  /* hash chain */
 197         TAILQ_ENTRY(namecache) nc_lru;  /* LRU chain */
 198         struct  vnode *nc_dvp;          /* vnode of parent of name */
 199         u_long  nc_dvpid;               /* capability number of nc_dvp */
 200         struct  vnode *nc_vp;           /* vnode the name refers to */
 201         u_long  nc_vpid;                /* capability number of nc_vp */
 202         char    nc_nlen;                /* length of name */
 203         char    nc_name[NCHNAMLEN];     /* segment name */
 204 };
 205
 206 #ifdef KERNEL
 207 struct mount;
 208 extern u_long   nextvnodeid;
 209 int     namei __P((struct nameidata *ndp));
 210 int     lookup __P((struct nameidata *ndp));
 211 int     relookup __P((struct vnode *dvp, struct vnode **vpp,
 212                 struct componentname *cnp));
 213
 214 /* namecache function prototypes */
 215 int     cache_lookup __P((struct vnode *dvp, struct vnode **vpp,
 216                 struct componentname *cnp));
 217 void    cache_enter __P((struct vnode *dvp, struct vnode *vpp,
 218                 struct componentname *cnp));
 219 void    cache_purge __P((struct vnode *vp));
 220 void    cache_purgevfs __P((struct mount *mp));
 221 #endif /* KERNEL */
 222
 223 /*
 224  * Stats on usefulness of namei caches.
 225  */
 226 struct  nchstats {
 227         long    ncs_goodhits;           /* hits that we can really use */
 228         long    ncs_neghits;            /* negative hits that we can use */
 229         long    ncs_badhits;            /* hits we must drop */
 230         long    ncs_falsehits;          /* hits with id mismatch */
 231         long    ncs_miss;               /* misses */
 232         long    ncs_long;               /* long names that ignore cache */
 233         long    ncs_pass2;              /* names found with passes == 2 */
 234         long    ncs_2passes;            /* number of times we attempt it */
 235 };
 236 #endif /* __APPLE_API_UNSTABLE */
 237
 238 #endif /* !_SYS_NAMEI_H_ */