Annotation of XNU/bsd/sys/namei.h, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 2000 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/queue.h>
                     62: #include <sys/uio.h>
                     63: 
                     64: /*
                     65:  * Encapsulation of namei parameters.
                     66:  */
                     67: struct nameidata {
                     68:        /*
                     69:         * Arguments to namei/lookup.
                     70:         */
                     71:        caddr_t ni_dirp;                /* pathname pointer */
                     72:        enum    uio_seg ni_segflg;      /* location of pathname */
                     73:      /* u_long ni_nameiop;                namei operation */
                     74:      /* u_long ni_flags;                  flags to namei */
                     75:      /* struct proc *ni_proc;             process requesting lookup */
                     76:        /*
                     77:         * Arguments to lookup.
                     78:         */
                     79:      /* struct ucred *ni_cred;            credentials */
                     80:        struct  vnode *ni_startdir;     /* starting directory */
                     81:        struct  vnode *ni_rootdir;      /* logical root directory */
                     82:        /*
                     83:         * Results: returned from/manipulated by lookup
                     84:         */
                     85:        struct  vnode *ni_vp;           /* vnode of result */
                     86:        struct  vnode *ni_dvp;          /* vnode of intermediate directory */
                     87:        /*
                     88:         * Shared between namei and lookup/commit routines.
                     89:         */
                     90:        u_int   ni_pathlen;             /* remaining chars in path */
                     91:        char    *ni_next;               /* next location in pathname */
                     92:        u_long  ni_loopcnt;             /* count of symlinks encountered */
                     93:        /*
                     94:         * Lookup parameters: this structure describes the subset of
                     95:         * information from the nameidata structure that is passed
                     96:         * through the VOP interface.
                     97:         */
                     98:        struct componentname {
                     99:                /*
                    100:                 * Arguments to lookup.
                    101:                 */
                    102:                u_long  cn_nameiop;     /* namei operation */
                    103:                u_long  cn_flags;       /* flags to namei */
                    104:                struct  proc *cn_proc;  /* process requesting lookup */
                    105:                struct  ucred *cn_cred; /* credentials */
                    106:                /*
                    107:                 * Shared between lookup and commit routines.
                    108:                 */
                    109:                char    *cn_pnbuf;      /* pathname buffer */
                    110:                long    cn_pnlen;       /* length of allocated buffer */
                    111:                char    *cn_nameptr;    /* pointer to looked up name */
                    112:                long    cn_namelen;     /* length of looked up component */
                    113:                u_long  cn_hash;        /* hash value of looked up name */
                    114:                long    cn_consume;     /* chars to consume in lookup() */
                    115:        } ni_cnd;
                    116: };
                    117: 
                    118: #ifdef KERNEL
                    119: /*
                    120:  * namei operations
                    121:  */
                    122: #define        LOOKUP          0       /* perform name lookup only */
                    123: #define        CREATE          1       /* setup for file creation */
                    124: #define        DELETE          2       /* setup for file deletion */
                    125: #define        RENAME          3       /* setup for file renaming */
                    126: #define        OPMASK          3       /* mask for operation */
                    127: /*
                    128:  * namei operational modifier flags, stored in ni_cnd.flags
                    129:  */
                    130: #define        LOCKLEAF        0x0004  /* lock inode on return */
                    131: #define        LOCKPARENT      0x0008  /* want parent vnode returned locked */
                    132: #define        WANTPARENT      0x0010  /* want parent vnode returned unlocked */
                    133: #define        NOCACHE         0x0020  /* name must not be left in cache */
                    134: #define        FOLLOW          0x0040  /* follow symbolic links */
                    135: #define        NOFOLLOW        0x0000  /* do not follow symbolic links (pseudo) */
                    136: #define        MODMASK         0x00fc  /* mask of operational modifiers */
                    137: /*
                    138:  * Namei parameter descriptors.
                    139:  *
                    140:  * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
                    141:  * If the caller of namei sets the flag (for example execve wants to
                    142:  * know the name of the program that is being executed), then it must
                    143:  * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
                    144:  * be freed by either the commit routine or the VOP_ABORT routine.
                    145:  * SAVESTART is set only by the callers of namei. It implies SAVENAME
                    146:  * plus the addition of saving the parent directory that contains the
                    147:  * name in ni_startdir. It allows repeated calls to lookup for the
                    148:  * name being sought. The caller is responsible for releasing the
                    149:  * buffer and for vrele'ing ni_startdir.
                    150:  */
                    151: #define        NOCROSSMOUNT    0x000100 /* do not cross mount points */
                    152: #define        RDONLY          0x000200 /* lookup with read-only semantics */
                    153: #define        HASBUF          0x000400 /* has allocated pathname buffer */
                    154: #define        SAVENAME        0x000800 /* save pathanme buffer */
                    155: #define        SAVESTART       0x001000 /* save starting directory */
                    156: #define        ISDOTDOT        0x002000 /* current component name is .. */
                    157: #define        MAKEENTRY       0x004000 /* entry is to be added to name cache */
                    158: #define        ISLASTCN        0x008000 /* this is last component of pathname */
                    159: #define        ISSYMLINK       0x010000 /* symlink needs interpretation */
                    160: #define        ISWHITEOUT      0x020000 /* found whiteout */
                    161: #define        DOWHITEOUT      0x040000 /* do whiteouts */
                    162: #define        NODELETEBUSY    0x800000 /* do not delete busy files (HFS semantic) */
                    163: #define        PARAMASK        0x0fff00 /* mask of parameter descriptors */
                    164: /*
                    165:  * Initialization of an nameidata structure.
                    166:  */
                    167: #define NDINIT(ndp, op, flags, segflg, namep, p) { \
                    168:        (ndp)->ni_cnd.cn_nameiop = op; \
                    169:        (ndp)->ni_cnd.cn_flags = flags; \
                    170:        (ndp)->ni_segflg = segflg; \
                    171:        (ndp)->ni_dirp = namep; \
                    172:        (ndp)->ni_cnd.cn_proc = p; \
                    173: }
                    174: #endif /* KERNEL */
                    175: 
                    176: /*
                    177:  * This structure describes the elements in the cache of recent
                    178:  * names looked up by namei. NCHNAMLEN is sized to make structure
                    179:  * size a power of two to optimize malloc's. Minimum reasonable
                    180:  * size is 15.
                    181:  */
                    182: 
                    183: #define        NCHNAMLEN       31      /* maximum name segment length we bother with */
                    184: 
                    185: struct namecache {
                    186:        LIST_ENTRY(namecache) nc_hash;  /* hash chain */
                    187:        TAILQ_ENTRY(namecache) nc_lru;  /* LRU chain */
                    188:        struct  vnode *nc_dvp;          /* vnode of parent of name */
                    189:        u_long  nc_dvpid;               /* capability number of nc_dvp */
                    190:        struct  vnode *nc_vp;           /* vnode the name refers to */
                    191:        u_long  nc_vpid;                /* capability number of nc_vp */
                    192:        char    nc_nlen;                /* length of name */
                    193:        char    nc_name[NCHNAMLEN];     /* segment name */
                    194: };
                    195: 
                    196: #ifdef KERNEL
                    197: extern u_long  nextvnodeid;
                    198: int    namei __P((struct nameidata *ndp));
                    199: int    lookup __P((struct nameidata *ndp));
                    200: int    relookup __P((struct vnode *dvp, struct vnode **vpp,
                    201:            struct componentname *cnp));
                    202: #endif /* KERNEL */
                    203: 
                    204: /*
                    205:  * Stats on usefulness of namei caches.
                    206:  */
                    207: struct nchstats {
                    208:        long    ncs_goodhits;           /* hits that we can really use */
                    209:        long    ncs_neghits;            /* negative hits that we can use */
                    210:        long    ncs_badhits;            /* hits we must drop */
                    211:        long    ncs_falsehits;          /* hits with id mismatch */
                    212:        long    ncs_miss;               /* misses */
                    213:        long    ncs_long;               /* long names that ignore cache */
                    214:        long    ncs_pass2;              /* names found with passes == 2 */
                    215:        long    ncs_2passes;            /* number of times we attempt it */
                    216: };
                    217: #endif /* !_SYS_NAMEI_H_ */

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