Annotation of kernel/bsd/sys/namei.h, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
        !             7:  * Reserved.  This file contains Original Code and/or Modifications of
        !             8:  * Original Code as defined in and that are subject to the Apple Public
        !             9:  * Source License Version 1.1 (the "License").  You may not use this file
        !            10:  * except in compliance with the License.  Please obtain a copy of the
        !            11:  * License at http://www.apple.com/publicsource and read it before using
        !            12:  * this file.
        !            13:  * 
        !            14:  * The Original Code and all software distributed under the License are
        !            15:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            16:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            17:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            18:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            19:  * License for the specific language governing rights and limitations
        !            20:  * under the License.
        !            21:  * 
        !            22:  * @APPLE_LICENSE_HEADER_END@
        !            23:  */
        !            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     8.5 (Berkeley) 1/9/95
        !            59:  */
        !            60: 
        !            61: #ifndef _SYS_NAMEI_H_
        !            62: #define        _SYS_NAMEI_H_
        !            63: 
        !            64: #include <sys/queue.h>
        !            65: #include <sys/uio.h>
        !            66: 
        !            67: /*
        !            68:  * Encapsulation of namei parameters.
        !            69:  */
        !            70: struct nameidata {
        !            71:        /*
        !            72:         * Arguments to namei/lookup.
        !            73:         */
        !            74:        caddr_t ni_dirp;                /* pathname pointer */
        !            75:        enum    uio_seg ni_segflg;      /* location of pathname */
        !            76:      /* u_long ni_nameiop;                namei operation */
        !            77:      /* u_long ni_flags;                  flags to namei */
        !            78:      /* struct proc *ni_proc;             process requesting lookup */
        !            79:        /*
        !            80:         * Arguments to lookup.
        !            81:         */
        !            82:      /* struct ucred *ni_cred;            credentials */
        !            83:        struct  vnode *ni_startdir;     /* starting directory */
        !            84:        struct  vnode *ni_rootdir;      /* logical root directory */
        !            85:        /*
        !            86:         * Results: returned from/manipulated by lookup
        !            87:         */
        !            88:        struct  vnode *ni_vp;           /* vnode of result */
        !            89:        struct  vnode *ni_dvp;          /* vnode of intermediate directory */
        !            90:        /*
        !            91:         * Shared between namei and lookup/commit routines.
        !            92:         */
        !            93:        u_int   ni_pathlen;             /* remaining chars in path */
        !            94:        char    *ni_next;               /* next location in pathname */
        !            95:        u_long  ni_loopcnt;             /* count of symlinks encountered */
        !            96:        /*
        !            97:         * Lookup parameters: this structure describes the subset of
        !            98:         * information from the nameidata structure that is passed
        !            99:         * through the VOP interface.
        !           100:         */
        !           101:        struct componentname {
        !           102:                /*
        !           103:                 * Arguments to lookup.
        !           104:                 */
        !           105:                u_long  cn_nameiop;     /* namei operation */
        !           106:                u_long  cn_flags;       /* flags to namei */
        !           107:                struct  proc *cn_proc;  /* process requesting lookup */
        !           108:                struct  ucred *cn_cred; /* credentials */
        !           109:                /*
        !           110:                 * Shared between lookup and commit routines.
        !           111:                 */
        !           112:                char    *cn_pnbuf;      /* pathname buffer */
        !           113:                long    cn_pnlen;       /* length of allocated buffer */
        !           114:                char    *cn_nameptr;    /* pointer to looked up name */
        !           115:                long    cn_namelen;     /* length of looked up component */
        !           116:                u_long  cn_hash;        /* hash value of looked up name */
        !           117:                long    cn_consume;     /* chars to consume in lookup() */
        !           118:        } ni_cnd;
        !           119: };
        !           120: 
        !           121: #ifdef _KERNEL
        !           122: /*
        !           123:  * namei operations
        !           124:  */
        !           125: #define        LOOKUP          0       /* perform name lookup only */
        !           126: #define        CREATE          1       /* setup for file creation */
        !           127: #define        DELETE          2       /* setup for file deletion */
        !           128: #define        RENAME          3       /* setup for file renaming */
        !           129: #define        OPMASK          3       /* mask for operation */
        !           130: /*
        !           131:  * namei operational modifier flags, stored in ni_cnd.flags
        !           132:  */
        !           133: #define        LOCKLEAF        0x0004  /* lock inode on return */
        !           134: #define        LOCKPARENT      0x0008  /* want parent vnode returned locked */
        !           135: #define        WANTPARENT      0x0010  /* want parent vnode returned unlocked */
        !           136: #define        NOCACHE         0x0020  /* name must not be left in cache */
        !           137: #define        FOLLOW          0x0040  /* follow symbolic links */
        !           138: #define        NOFOLLOW        0x0000  /* do not follow symbolic links (pseudo) */
        !           139: #define        MODMASK         0x00fc  /* mask of operational modifiers */
        !           140: /*
        !           141:  * Namei parameter descriptors.
        !           142:  *
        !           143:  * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
        !           144:  * If the caller of namei sets the flag (for example execve wants to
        !           145:  * know the name of the program that is being executed), then it must
        !           146:  * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
        !           147:  * be freed by either the commit routine or the VOP_ABORT routine.
        !           148:  * SAVESTART is set only by the callers of namei. It implies SAVENAME
        !           149:  * plus the addition of saving the parent directory that contains the
        !           150:  * name in ni_startdir. It allows repeated calls to lookup for the
        !           151:  * name being sought. The caller is responsible for releasing the
        !           152:  * buffer and for vrele'ing ni_startdir.
        !           153:  */
        !           154: #define        NOCROSSMOUNT    0x00100 /* do not cross mount points */
        !           155: #define        RDONLY          0x00200 /* lookup with read-only semantics */
        !           156: #define        HASBUF          0x00400 /* has allocated pathname buffer */
        !           157: #define        SAVENAME        0x00800 /* save pathanme buffer */
        !           158: #define        SAVESTART       0x01000 /* save starting directory */
        !           159: #define ISDOTDOT       0x02000 /* current component name is .. */
        !           160: #define MAKEENTRY      0x04000 /* entry is to be added to name cache */
        !           161: #define ISLASTCN       0x08000 /* this is last component of pathname */
        !           162: #define ISSYMLINK      0x10000 /* symlink needs interpretation */
        !           163: #define        ISWHITEOUT      0x20000 /* found whiteout */
        !           164: #define        DOWHITEOUT      0x40000 /* do whiteouts */
        !           165: #define PARAMASK       0xfff00 /* mask of parameter descriptors */
        !           166: /*
        !           167:  * Initialization of an nameidata structure.
        !           168:  */
        !           169: #define NDINIT(ndp, op, flags, segflg, namep, p) { \
        !           170:        (ndp)->ni_cnd.cn_nameiop = op; \
        !           171:        (ndp)->ni_cnd.cn_flags = flags; \
        !           172:        (ndp)->ni_segflg = segflg; \
        !           173:        (ndp)->ni_dirp = namep; \
        !           174:        (ndp)->ni_cnd.cn_proc = p; \
        !           175: }
        !           176: #endif /* _KERNEL */
        !           177: 
        !           178: /*
        !           179:  * This structure describes the elements in the cache of recent
        !           180:  * names looked up by namei. NCHNAMLEN is sized to make structure
        !           181:  * size a power of two to optimize malloc's. Minimum reasonable
        !           182:  * size is 15.
        !           183:  */
        !           184: 
        !           185: #define        NCHNAMLEN       31      /* maximum name segment length we bother with */
        !           186: 
        !           187: struct namecache {
        !           188:        LIST_ENTRY(namecache) nc_hash;  /* hash chain */
        !           189:        TAILQ_ENTRY(namecache) nc_lru;  /* LRU chain */
        !           190:        struct  vnode *nc_dvp;          /* vnode of parent of name */
        !           191:        u_long  nc_dvpid;               /* capability number of nc_dvp */
        !           192:        struct  vnode *nc_vp;           /* vnode the name refers to */
        !           193:        u_long  nc_vpid;                /* capability number of nc_vp */
        !           194:        char    nc_nlen;                /* length of name */
        !           195:        char    nc_name[NCHNAMLEN];     /* segment name */
        !           196: };
        !           197: 
        !           198: #ifdef _KERNEL
        !           199: extern u_long  nextvnodeid;
        !           200: int    namei __P((struct nameidata *ndp));
        !           201: int    lookup __P((struct nameidata *ndp));
        !           202: int    relookup __P((struct vnode *dvp, struct vnode **vpp,
        !           203:            struct componentname *cnp));
        !           204: #endif /* _KERNEL */
        !           205: 
        !           206: /*
        !           207:  * Stats on usefulness of namei caches.
        !           208:  */
        !           209: struct nchstats {
        !           210:        long    ncs_goodhits;           /* hits that we can really use */
        !           211:        long    ncs_neghits;            /* negative hits that we can use */
        !           212:        long    ncs_badhits;            /* hits we must drop */
        !           213:        long    ncs_falsehits;          /* hits with id mismatch */
        !           214:        long    ncs_miss;               /* misses */
        !           215:        long    ncs_long;               /* long names that ignore cache */
        !           216:        long    ncs_pass2;              /* names found with passes == 2 */
        !           217:        long    ncs_2passes;            /* number of times we attempt it */
        !           218: };
        !           219: #endif /* !_SYS_NAMEI_H_ */

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