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

     /*
      * Copyright (c) 1990, 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. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. 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.
     *
     *      @(#)filedesc.h  8.1 (Berkeley) 6/2/93
     * $FreeBSD: src/sys/sys/filedesc.h,v 1.19.2.5 2003/06/06 20:21:32 tegge Exp $
     * $DragonFly: src/sys/sys/filedesc.h,v 1.20 2006/10/27 04:56:33 dillon Exp $
     */
    
    #ifndef _SYS_FILEDESC_H_
    #define _SYS_FILEDESC_H_
    
    #ifndef _SYS_TYPES_H_
    #include <sys/types.h>
    #endif
    #ifndef _SYS_QUEUE_H_
    #include <sys/queue.h>
    #endif
    #ifndef _SYS_SPINLOCK_H_
    #include <sys/spinlock.h>
    #endif
    #ifndef _SYS_NAMECACHE_H_
    #include <sys/namecache.h>
    #endif
    
    /*
     * This structure is used for the management of descriptors.  It may be
     * shared by multiple processes.
     *
     * A process is initially started out with NDFILE descriptors stored within
     * this structure, selected to be enough for typical applications based on
     * the historical limit of 20 open files (and the usage of descriptors by
     * shells) and the constraint of being one less than a power of 2.
     * If these descriptors are exhausted, a larger descriptor table
     * may be allocated, up to a process' resource limit; the internal arrays
     * are then unused.  Each time the file table runs out, it is doubled until
     * the resource limit is reached.
     */
    #define NDFILE          15              /* must be of the form 2^n - 1 */
    
    struct file;
    struct klist;
    
    struct fdnode {
            struct file *fp;
            char    fileflags;
            char    unused01;
            char    unused02;
            char    reserved;               /* descriptor has been reserved */
            int     allocated;              /* subtree allocation count */
    };
    
    struct filedesc {
            struct fdnode *fd_files;        /* file structures for open files */
            struct  vnode *fd_cdir;         /* current directory (phaseout) */
            struct  vnode *fd_rdir;         /* root directory (phaseout) */
            struct  vnode *fd_jdir;         /* jail root directory (phaseout) */
            struct  nchandle fd_ncdir;      /* current directory */
            struct  nchandle fd_nrdir;      /* root directory */
            struct  nchandle fd_njdir;      /* jail directory */
            int     fd_nfiles;              /* number of open files allocated */
            int     fd_lastfile;            /* high-water mark of fd_files */
            int     fd_freefile;            /* approx. next free file */
            int     fd_cmask;               /* mask for file creation */
            int     fd_refcnt;              /* reference count */
            int     fd_softrefs;            /* softrefs to prevent destruction */
            int     fd_holdleaderscount;    /* block fdfree() for shared close() */
            int     fd_holdleaderswakeup;   /* fdfree() needs wakeup */
            struct spinlock fd_spin;
            struct  fdnode  fd_builtin_files[NDFILE];
    };
   
   /*
    * Structure to keep track of (process leader, struct fildedesc) tuples.
    * Each process has a pointer to such a structure when detailed tracking
    * is needed. e.g. when rfork(RFPROC | RFMEM) causes a file descriptor
    * table to be shared by processes having different "p_leader" pointers
    * and thus distinct POSIX style locks.
    */
   struct filedesc_to_leader {
           int             fdl_refcount;   /* references from struct proc */
           int             fdl_holdcount;  /* temporary hold during closef */
           int             fdl_wakeup;     /* fdfree() waits on closef() */
           struct proc     *fdl_leader;    /* owner of POSIX locks */
           /* Circular list */
           struct filedesc_to_leader *fdl_prev;
           struct filedesc_to_leader *fdl_next;
   };
   
   /*
    * Per-process open flags.
    */
   #define UF_EXCLOSE      0x01            /* auto-close on exec */
   
   /*
    * This structure that holds the information needed to send a SIGIO or
    * a SIGURG signal to a process or process group when new data arrives
    * on a device or socket.  The structure is placed on an SLIST belonging
    * to the proc or pgrp so that the entire list may be revoked when the
    * process exits or the process group disappears.
    */
   struct  sigio {
           union {
                   struct  proc *siu_proc; /* process to receive SIGIO/SIGURG */
                   struct  pgrp *siu_pgrp; /* process group to receive ... */
           } sio_u;
           SLIST_ENTRY(sigio) sio_pgsigio; /* sigio's for process or group */
           struct  sigio **sio_myref;      /* location of the pointer that holds */
           struct  ucred *sio_ucred;       /* current credentials */
           uid_t   sio_ruid;               /* real user id */
           pid_t   sio_pgid;               /* pgid for signals */
   };
   #define sio_proc        sio_u.siu_proc
   #define sio_pgrp        sio_u.siu_pgrp
   
   SLIST_HEAD(sigiolst, sigio);
   
   #ifdef _KERNEL
   
   struct thread;
   struct proc;
   struct lwp;
   
   /*
    * Kernel global variables and routines.
    */
   int     dupfdopen (struct filedesc *, int, int, int, int);
   int     fdalloc (struct proc *p, int want, int *result);
   int     fdavail (struct proc *p, int n);
   int     falloc (struct lwp *lp, struct file **resultfp, int *resultfd);
   void    fsetfd (struct filedesc *fdp, struct file *fp, int fd);
   int     fgetfdflags(struct filedesc *fdp, int fd, int *flagsp);
   int     fsetfdflags(struct filedesc *fdp, int fd, int add_flags);
   int     fclrfdflags(struct filedesc *fdp, int fd, int rem_flags);
   void    fsetcred (struct file *fp, struct ucred *cr);
   void    fdinit_bootstrap(struct proc *p0, struct filedesc *fdp0, int cmask);
   struct  filedesc *fdinit (struct proc *p);
   struct  filedesc *fdshare (struct proc *p);
   int     fdcopy (struct proc *p, struct filedesc **fpp);
   void    fdfree (struct proc *p, struct filedesc *repl);
   int     fdrevoke(void *f_data, short f_type, struct ucred *cred);
   int     closef (struct file *fp, struct proc *p);
   void    fdcloseexec (struct proc *p);
   int     fdcheckstd (struct lwp *lp);
   struct  file *holdfp (struct filedesc *fdp, int fd, int flag);
   int     holdsock (struct filedesc *fdp, int fdes, struct file **fpp);
   int     holdvnode (struct filedesc *fdp, int fd, struct file **fpp);
   int     fdissequential (struct file *);
   void    fdsequential (struct file *, int);
   pid_t   fgetown (struct sigio **);
   int     fsetown (pid_t, struct sigio **);
   void    funsetown (struct sigio **);
   void    funsetownlst (struct sigiolst *);
   void    setugidsafety (struct proc *p);
   void    allfiles_scan_exclusive(int (*callback)(struct file *, void *), void *data);
   
   struct filedesc_to_leader *
   filedesc_to_leader_alloc(struct filedesc_to_leader *old,
                            struct proc *leader);
   
   #endif
   
   #endif

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