FreeBSD/Linux Kernel Cross Reference
sys/sys/namei.h

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 1985, 1989, 1991, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)namei.h     8.5 (Berkeley) 1/9/95
     * $FreeBSD: releng/12.0/sys/sys/namei.h 331621 2018-03-27 15:20:03Z brooks $
     */
    
    #ifndef _SYS_NAMEI_H_
    #define _SYS_NAMEI_H_
    
    #include <sys/caprights.h>
    #include <sys/filedesc.h>
    #include <sys/queue.h>
    #include <sys/_uio.h>
    
    struct componentname {
            /*
             * Arguments to lookup.
             */
            u_long  cn_nameiop;     /* namei operation */
            u_int64_t cn_flags;     /* flags to namei */
            struct  thread *cn_thread;/* thread requesting lookup */
            struct  ucred *cn_cred; /* credentials */
            int     cn_lkflags;     /* Lock flags LK_EXCLUSIVE or LK_SHARED */
            /*
             * Shared between lookup and commit routines.
             */
            char    *cn_pnbuf;      /* pathname buffer */
            char    *cn_nameptr;    /* pointer to looked up name */
            long    cn_namelen;     /* length of looked up component */
    };
    
    struct nameicap_tracker;
    TAILQ_HEAD(nameicap_tracker_head, nameicap_tracker);
    
    /*
     * Encapsulation of namei parameters.
     */
    struct nameidata {
            /*
             * Arguments to namei/lookup.
             */
            const   char *ni_dirp;          /* pathname pointer */
            enum    uio_seg ni_segflg;      /* location of pathname */
            cap_rights_t ni_rightsneeded;   /* rights required to look up vnode */
            /*
             * Arguments to lookup.
             */
            struct  vnode *ni_startdir;     /* starting directory */
            struct  vnode *ni_rootdir;      /* logical root directory */
            struct  vnode *ni_topdir;       /* logical top directory */
            int     ni_dirfd;               /* starting directory for *at functions */
            int     ni_lcf;                 /* local call flags */
            /*
             * Results: returned from namei
             */
            struct filecaps ni_filecaps;    /* rights the *at base has */
            /*
             * Results: returned from/manipulated by lookup
             */
            struct  vnode *ni_vp;           /* vnode of result */
            struct  vnode *ni_dvp;          /* vnode of intermediate directory */
            /*
             * Shared between namei and lookup/commit routines.
             */
            size_t  ni_pathlen;             /* remaining chars in path */
            char    *ni_next;               /* next location in pathname */
            u_int   ni_loopcnt;             /* count of symlinks encountered */
            /*
             * Lookup parameters: this structure describes the subset of
             * information from the nameidata structure that is passed
             * through the VOP interface.
            */
           struct componentname ni_cnd;
           struct nameicap_tracker_head ni_cap_tracker;
   };
   
   #ifdef _KERNEL
   /*
    * namei operations
    */
   #define LOOKUP          0       /* perform name lookup only */
   #define CREATE          1       /* setup for file creation */
   #define DELETE          2       /* setup for file deletion */
   #define RENAME          3       /* setup for file renaming */
   #define OPMASK          3       /* mask for operation */
   /*
    * namei operational modifier flags, stored in ni_cnd.flags
    */
   #define LOCKLEAF        0x0004  /* lock vnode on return */
   #define LOCKPARENT      0x0008  /* want parent vnode returned locked */
   #define WANTPARENT      0x0010  /* want parent vnode returned unlocked */
   #define NOCACHE         0x0020  /* name must not be left in cache */
   #define FOLLOW          0x0040  /* follow symbolic links */
   #define LOCKSHARED      0x0100  /* Shared lock leaf */
   #define NOFOLLOW        0x0000  /* do not follow symbolic links (pseudo) */
   #define MODMASK         0x01fc  /* mask of operational modifiers */
   /*
    * Namei parameter descriptors.
    *
    * SAVENAME may be set by either the callers of namei or by VOP_LOOKUP.
    * If the caller of namei sets the flag (for example execve wants to
    * know the name of the program that is being executed), then it must
    * free the buffer. If VOP_LOOKUP sets the flag, then the buffer must
    * be freed by either the commit routine or the VOP_ABORT routine.
    * SAVESTART is set only by the callers of namei. It implies SAVENAME
    * plus the addition of saving the parent directory that contains the
    * name in ni_startdir. It allows repeated calls to lookup for the
    * name being sought. The caller is responsible for releasing the
    * buffer and for vrele'ing ni_startdir.
    */
   #define RDONLY          0x00000200 /* lookup with read-only semantics */
   #define HASBUF          0x00000400 /* has allocated pathname buffer */
   #define SAVENAME        0x00000800 /* save pathname buffer */
   #define SAVESTART       0x00001000 /* save starting directory */
   #define ISDOTDOT        0x00002000 /* current component name is .. */
   #define MAKEENTRY       0x00004000 /* entry is to be added to name cache */
   #define ISLASTCN        0x00008000 /* this is last component of pathname */
   #define ISSYMLINK       0x00010000 /* symlink needs interpretation */
   #define ISWHITEOUT      0x00020000 /* found whiteout */
   #define DOWHITEOUT      0x00040000 /* do whiteouts */
   #define WILLBEDIR       0x00080000 /* new files will be dirs; allow trailing / */
   #define ISUNICODE       0x00100000 /* current component name is unicode*/
   #define ISOPEN          0x00200000 /* caller is opening; return a real vnode. */
   #define NOCROSSMOUNT    0x00400000 /* do not cross mount points */
   #define NOMACCHECK      0x00800000 /* do not perform MAC checks */
   #define AUDITVNODE1     0x04000000 /* audit the looked up vnode information */
   #define AUDITVNODE2     0x08000000 /* audit the looked up vnode information */
   #define TRAILINGSLASH   0x10000000 /* path ended in a slash */
   #define NOCAPCHECK      0x20000000 /* do not perform capability checks */
   #define PARAMASK        0x3ffffe00 /* mask of parameter descriptors */
   
   /*
    * Flags in ni_lcf, valid for the duration of the namei call.
    */
   #define NI_LCF_STRICTRELATIVE   0x0001  /* relative lookup only */
   #define NI_LCF_CAP_DOTDOT       0x0002  /* ".." in strictrelative case */
   
   /*
    * Initialization of a nameidata structure.
    */
   #define NDINIT(ndp, op, flags, segflg, namep, td)                       \
           NDINIT_ALL(ndp, op, flags, segflg, namep, AT_FDCWD, NULL, 0, td)
   #define NDINIT_AT(ndp, op, flags, segflg, namep, dirfd, td)             \
           NDINIT_ALL(ndp, op, flags, segflg, namep, dirfd, NULL, 0, td)
   #define NDINIT_ATRIGHTS(ndp, op, flags, segflg, namep, dirfd, rightsp, td) \
           NDINIT_ALL(ndp, op, flags, segflg, namep, dirfd, NULL, rightsp, td)
   #define NDINIT_ATVP(ndp, op, flags, segflg, namep, vp, td)              \
           NDINIT_ALL(ndp, op, flags, segflg, namep, AT_FDCWD, vp, 0, td)
   
   void NDINIT_ALL(struct nameidata *ndp, u_long op, u_long flags,
       enum uio_seg segflg, const char *namep, int dirfd, struct vnode *startdir,
       cap_rights_t *rightsp, struct thread *td);
   
   #define NDF_NO_DVP_RELE         0x00000001
   #define NDF_NO_DVP_UNLOCK       0x00000002
   #define NDF_NO_DVP_PUT          0x00000003
   #define NDF_NO_VP_RELE          0x00000004
   #define NDF_NO_VP_UNLOCK        0x00000008
   #define NDF_NO_VP_PUT           0x0000000c
   #define NDF_NO_STARTDIR_RELE    0x00000010
   #define NDF_NO_FREE_PNBUF       0x00000020
   #define NDF_ONLY_PNBUF          (~NDF_NO_FREE_PNBUF)
   
   void NDFREE(struct nameidata *, const u_int);
   
   int     namei(struct nameidata *ndp);
   int     lookup(struct nameidata *ndp);
   int     relookup(struct vnode *dvp, struct vnode **vpp,
               struct componentname *cnp);
   #endif
   
   /*
    * Stats on usefulness of namei caches.
    */
   struct nchstats {
           long    ncs_goodhits;           /* hits that we can really use */
           long    ncs_neghits;            /* negative hits that we can use */
           long    ncs_badhits;            /* hits we must drop */
           long    ncs_falsehits;          /* hits with id mismatch */
           long    ncs_miss;               /* misses */
           long    ncs_long;               /* long names that ignore cache */
           long    ncs_pass2;              /* names found with passes == 2 */
           long    ncs_2passes;            /* number of times we attempt it */
   };
   
   extern struct nchstats nchstats;
   
   #endif /* !_SYS_NAMEI_H_ */

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