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/*
* 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
* $FreeBSD$
*/
#ifndef _SYS_FILEDESC_H_
#define _SYS_FILEDESC_H_
/*
* 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). If these descriptors are exhausted, a larger descriptor table
* may be allocated, up to a process' resource limit; the internal arrays
* are then unused. The initial expansion is set to NDEXTENT; each time
* it runs out, it is doubled until the resource limit is reached. NDEXTENT
* should be selected to be the biggest multiple of OFILESIZE (see below)
* that will fit in a power-of-two sized piece of memory.
*/
#define NDFILE 20
#define NDEXTENT 50 /* 250 bytes in 256-byte alloc. */
struct filedesc {
struct file **fd_ofiles; /* file structures for open files */
char *fd_ofileflags; /* per-process open file flags */
struct vnode *fd_cdir; /* current directory */
struct vnode *fd_rdir; /* root directory */
int fd_nfiles; /* number of open files allocated */
u_short fd_lastfile; /* high-water mark of fd_ofiles */
u_short fd_freefile; /* approx. next free file */
u_short fd_cmask; /* mask for file creation */
u_short fd_refcnt; /* reference count */
};
/*
* Basic allocation of descriptors:
* one of the above, plus arrays for NDFILE descriptors.
*/
struct filedesc0 {
struct filedesc fd_fd;
/*
* These arrays are used when the number of open files is
* <= NDFILE, and are then pointed to by the pointers above.
*/
struct file *fd_dfiles[NDFILE];
char fd_dfileflags[NDFILE];
};
/*
* Per-process open flags.
*/
#define UF_EXCLOSE 0x01 /* auto-close on exec */
#define UF_MAPPED 0x02 /* mapped from device */
/*
* Storage required per open file descriptor.
*/
#define OFILESIZE (sizeof(struct file *) + sizeof(char))
#ifdef KERNEL
/*
* Kernel global variables and routines.
*/
int dupfdopen __P((struct filedesc *, int, int, int, int));
int fdalloc __P((struct proc *p, int want, int *result));
int fdavail __P((struct proc *p, int n));
int falloc __P((struct proc *p, struct file **resultfp, int *resultfd));
void ffree __P((struct file *));
struct filedesc *fdinit __P((struct proc *p));
struct filedesc *fdshare __P((struct proc *p));
struct filedesc *fdcopy __P((struct proc *p));
void fdfree __P((struct proc *p));
int closef __P((struct file *fp,struct proc *p));
void fdcloseexec __P((struct proc *p));
int getvnode __P((struct filedesc *fdp, int fd, struct file **fpp));
int fdissequential __P((struct file *));
void fdsequential __P((struct file *, int));
#endif
#endif
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