bsd/sys/namei.h

   1 /*
   2  * Copyright (c) 2000-2011 Apple 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 /* VFS Supports "/..namedfork/rsrc" access. */
  79 #define NAMEDRSRCFORK           NAMEDSTREAMS
  80
  81
  82 #include <sys/queue.h>
  83 #include <sys/uio.h>
  84 #include <sys/vnode.h>
  85 #include <sys/mount.h>
  86 #include <sys/filedesc.h>
  87
  88 #define PATHBUFLEN      256
  89
  90 /*
  91  * Encapsulation of namei parameters.
  92  */
  93 struct nameidata {
  94         /*
  95          * Arguments to namei/lookup.
  96          */
  97         user_addr_t ni_dirp;            /* pathname pointer */
  98         enum    uio_seg ni_segflg;      /* location of pathname */
  99 #if CONFIG_TRIGGERS
 100         enum    path_operation ni_op;   /* intended operation, see enum path_operation in vnode.h */
 101 #endif /* CONFIG_TRIGGERS */
 102         /*
 103          * Arguments to lookup.
 104          */
 105         struct  vnode *ni_startdir;     /* starting directory */
 106         struct  vnode *ni_rootdir;      /* logical root directory */
 107         struct  vnode *ni_usedvp;       /* directory passed in via USEDVP */
 108         /*
 109          * Results: returned from/manipulated by lookup
 110          */
 111         struct  vnode *ni_vp;           /* vnode of result */
 112         struct  vnode *ni_dvp;          /* vnode of intermediate directory */
 113         /*
 114          * Shared between namei and lookup/commit routines.
 115          */
 116         u_int   ni_pathlen;             /* remaining chars in path */
 117         char    *ni_next;               /* next location in pathname */
 118         char    ni_pathbuf[PATHBUFLEN];
 119         u_long  ni_loopcnt;             /* count of symlinks encountered */
 120
 121         struct componentname ni_cnd;
 122         int32_t ni_flag;
 123         int ni_ncgeneration;            /* For a batched vnop, grab generation beforehand */
 124 };
 125
 126 #define NAMEI_CONTLOOKUP        0x002    /* Continue processing a lookup which was partially processed in a compound VNOP */
 127 #define NAMEI_TRAILINGSLASH     0x004    /* There was at least one trailing slash after last component */
 128 #define NAMEI_UNFINISHED        0x008    /* We broke off a lookup to do a compound op */
 129 /*
 130  * XXX Hack: we need to encode the intended VNOP in order to
 131  * be able to include information about which operations a filesystem
 132  * supports in the decision to break off a lookup early.
 133  */
 134 #define NAMEI_COMPOUNDOPEN      0x010
 135 #define NAMEI_COMPOUNDREMOVE    0x020
 136 #define NAMEI_COMPOUNDMKDIR     0x040
 137 #define NAMEI_COMPOUNDRMDIR     0x080
 138 #define NAMEI_COMPOUNDRENAME    0x100
 139 #define NAMEI_COMPOUND_OP_MASK (NAMEI_COMPOUNDOPEN | NAMEI_COMPOUNDREMOVE | NAMEI_COMPOUNDMKDIR | NAMEI_COMPOUNDRMDIR | NAMEI_COMPOUNDRENAME)
 140
 141 #ifdef KERNEL
 142 /*
 143  * namei operational modifier flags, stored in ni_cnd.flags
 144  * Also includes LOCKLEAF, LOCKPARENT, and WANTPARENT flags, defined above.
 145  */
 146 #define NOCACHE         0x00000020 /* name must not be left in cache */
 147 #define NOFOLLOW        0x00000000 /* do not follow symbolic links (pseudo) */
 148 /* public FOLLOW        0x00000040    see vnode.h */
 149 #define SHAREDLEAF      0x00000080 /* OK to have shared leaf lock */
 150 /* public NOTRIGGER     0x10000000    see vnode.h */
 151 #define MODMASK         0x100000fc /* mask of operational modifiers */
 152 /*
 153  * Namei parameter descriptors.
 154  *
 155  * SAVESTART is set only by the callers of namei. It implies SAVENAME
 156  * plus the addition of saving the parent directory that contains the
 157  * name in ni_startdir. It allows repeated calls to lookup for the
 158  * name being sought. The caller is responsible for releasing the
 159  * buffer and for vrele'ing ni_startdir.
 160  */
 161 #define SAVENAME        0          /* save pathanme buffer ***obsolete */
 162 #define NOCROSSMOUNT    0x00000100 /* do not cross mount points */
 163 #define RDONLY          0x00000200 /* lookup with read-only semantics */
 164 #define HASBUF          0x00000400 /* has allocated pathname buffer */
 165 #define DONOTAUTH       0x00000800 /* do not authorize during lookup */
 166 #define SAVESTART       0x00001000 /* save starting directory */
 167 /* public ISDOTDOT      0x00002000    see vnode.h */
 168 /* public MAKEENTRY     0x00004000    see vnode.h */
 169 /* public ISLASTCN      0x00008000    see vnode.h */
 170 #define ISSYMLINK       0x00010000 /* symlink needs interpretation */
 171 /* public ISWHITEOUT    0x00020000    see vnode.h */
 172 /* public DOWHITEOUT    0x00040000    see vnode.h */
 173 #define WILLBEDIR       0x00080000 /* new files will be dirs; allow trailing / */
 174 #define AUDITVNPATH1    0x00100000 /* audit the path/vnode info */
 175 #define AUDITVNPATH2    0x00200000 /* audit the path/vnode info */
 176 #define USEDVP          0x00400000 /* start the lookup at ndp.ni_dvp */
 177 #define CN_VOLFSPATH    0x00800000 /* user path was a volfs style path */
 178 #define UNIONCREATED    0x02000000 /* union fs creation of vnode */
 179 #if NAMEDRSRCFORK
 180 #define CN_WANTSRSRCFORK 0x04000000
 181 #define CN_ALLOWRSRCFORK 0x08000000
 182 #endif
 183 /* public NOTRIGGER             0x10000000    see vnode.h */
 184 #define CN_NBMOUNTLOOK  0x20000000 /* do not block for cross mount lookups */
 185 #ifdef BSD_KERNEL_PRIVATE
 186 #define CN_SKIPNAMECACHE        0x40000000      /* skip cache during lookup(), allow FS to handle all components */
 187 #endif
 188
 189 /*
 190  * Initialization of an nameidata structure.
 191  */
 192
 193 #if CONFIG_TRIGGERS
 194 /* Note: vnode triggers require more precise path operation (ni_op) */
 195
 196 #define NDINIT(ndp, op, pop, flags, segflg, namep, ctx) { \
 197         (ndp)->ni_cnd.cn_nameiop = op; \
 198         (ndp)->ni_op = pop; \
 199         (ndp)->ni_cnd.cn_flags = flags; \
 200         if ((segflg) == UIO_USERSPACE) { \
 201                 (ndp)->ni_segflg = ((IS_64BIT_PROCESS(vfs_context_proc(ctx))) ? UIO_USERSPACE64 : UIO_USERSPACE32); \
 202         } \
 203         else { \
 204                 (ndp)->ni_segflg = segflg; \
 205         } \
 206         (ndp)->ni_dirp = namep; \
 207         (ndp)->ni_cnd.cn_context = ctx; \
 208         (ndp)->ni_flag = 0; \
 209         (ndp)->ni_cnd.cn_ndp = (ndp); \
 210 }
 211 #else
 212 #define NDINIT(ndp, op, _unused_, flags, segflg, namep, ctx) { \
 213         (ndp)->ni_cnd.cn_nameiop = op; \
 214         (ndp)->ni_cnd.cn_flags = flags; \
 215         if ((segflg) == UIO_USERSPACE) { \
 216                 (ndp)->ni_segflg = ((IS_64BIT_PROCESS(vfs_context_proc(ctx))) ? UIO_USERSPACE64 : UIO_USERSPACE32); \
 217         } \
 218         else { \
 219                 (ndp)->ni_segflg = segflg; \
 220         } \
 221         (ndp)->ni_dirp = namep; \
 222         (ndp)->ni_cnd.cn_context = ctx; \
 223         (ndp)->ni_flag = 0; \
 224         (ndp)->ni_cnd.cn_ndp = (ndp); \
 225 }
 226 #endif /* CONFIG_TRIGGERS */
 227
 228 #endif /* KERNEL */
 229
 230 /*
 231  * This structure describes the elements in the cache of recent
 232  * names looked up by namei.
 233  */
 234
 235 #define NCHASHMASK      0x7fffffff
 236
 237 struct  namecache {
 238         TAILQ_ENTRY(namecache)  nc_entry;       /* chain of all entries */
 239         LIST_ENTRY(namecache)   nc_hash;        /* hash chain */
 240         LIST_ENTRY(namecache)   nc_child;       /* chain of ncp's that are children of a vp */
 241         union {
 242           LIST_ENTRY(namecache)  nc_link;       /* chain of ncp's that 'name' a vp */
 243           TAILQ_ENTRY(namecache) nc_negentry;   /* chain of ncp's that 'name' a vp */
 244         } nc_un;
 245         vnode_t                 nc_dvp;         /* vnode of parent of name */
 246         vnode_t                 nc_vp;          /* vnode the name refers to */
 247         unsigned int            nc_whiteout:1,  /* name has whiteout applied */
 248                                 nc_hashval:31;  /* hashval of stringname */
 249         const char              *nc_name;       /* pointer to segment name in string cache */
 250 };
 251
 252
 253 #ifdef KERNEL
 254
 255 int     namei(struct nameidata *ndp);
 256 void    nameidone(struct nameidata *);
 257 int     lookup(struct nameidata *ndp);
 258 int     relookup(struct vnode *dvp, struct vnode **vpp,
 259                 struct componentname *cnp);
 260 int     lookup_traverse_union(vnode_t dvp, vnode_t *new_dvp, vfs_context_t ctx);
 261 void    lookup_compound_vnop_post_hook(int error, vnode_t dvp, vnode_t vp, struct nameidata *ndp, int did_create);
 262
 263 /*
 264  * namecache function prototypes
 265  */
 266 void    cache_purgevfs(mount_t mp);
 267 int             cache_lookup_path(struct nameidata *ndp, struct componentname *cnp, vnode_t dp,
 268                           vfs_context_t context, int *dp_authorized, vnode_t last_dp);
 269
 270 void            vnode_cache_authorized_action(vnode_t vp, vfs_context_t context, kauth_action_t action);
 271 void            vnode_uncache_authorized_action(vnode_t vp, kauth_action_t action);
 272 boolean_t       vnode_cache_is_stale(vnode_t vp);
 273 boolean_t       vnode_cache_is_authorized(vnode_t vp, vfs_context_t context, kauth_action_t action);
 274 int             lookup_validate_creation_path(struct nameidata *ndp);
 275 int             namei_compound_available(vnode_t dp, struct nameidata *ndp);
 276
 277 #endif /* KERNEL */
 278
 279 /*
 280  * Stats on usefulness of namei caches.
 281  */
 282 struct  nchstats {
 283         long    ncs_goodhits;           /* hits that we can really use */
 284         long    ncs_neghits;            /* negative hits that we can use */
 285         long    ncs_badhits;            /* hits we must drop */
 286         long    ncs_miss;               /* misses */
 287         long    ncs_pass2;              /* names found with passes == 2 */
 288         long    ncs_2passes;            /* number of times we attempt it */
 289         long    ncs_stolen;
 290         long    ncs_enters;
 291         long    ncs_deletes;
 292         long    ncs_badvid;
 293 };
 294 #endif /* BSD_KERNEL_PRIVATE */
 295
 296 #endif /* !_SYS_NAMEI_H_ */