108 lines
4.2 KiB
C
108 lines
4.2 KiB
C
/*
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)filedesc.h 7.4 (Berkeley) 5/4/91
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* $Id: filedesc.h,v 1.6 1994/01/04 12:26:46 cgd Exp $
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*/
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#ifndef _SYS_FILEDESC_H_
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#define _SYS_FILEDESC_H_
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/*
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* This structure is used for the management of descriptors. It may be
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* shared by multiple processes.
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*
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* A process is initially started out with NDFILE descriptors stored within
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* this structure, selected to be enough for typical applications based on
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* the historical limit of 20 open files (and the usage of descriptors by
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* shells). If these descriptors are exhausted, a larger descriptor table
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* may be allocated, up to a process' resource limit; the internal arrays
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* are then unused. The initial expansion is set to NDEXTENT; each time
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* it runs out, it is doubled until the resource limit is reached. NDEXTENT
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* should be selected to be the biggest multiple of OFILESIZE (see below)
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* that will fit in a power-of-two sized piece of memory.
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*/
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#define NDFILE 20
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#define NDEXTENT 50 /* 250 bytes in 256-byte alloc. */
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struct filedesc {
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struct file **fd_ofiles; /* file structures for open files */
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char *fd_ofileflags; /* per-process open file flags */
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struct vnode *fd_cdir; /* current directory */
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struct vnode *fd_rdir; /* root directory */
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int fd_nfiles; /* number of open files allocated */
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u_short fd_lastfile; /* high-water mark of fd_ofiles */
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u_short fd_freefile; /* approx. next free file */
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u_short fd_cmask; /* mask for file creation */
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u_short fd_refcnt; /* reference count */
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};
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/*
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* Basic allocation of descriptors:
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* one of the above, plus arrays for NDFILE descriptors.
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*/
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struct filedesc0 {
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struct filedesc fd_fd;
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/*
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* These arrays are used when the number of open files is
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* <= NDFILE, and are then pointed to by the pointers above.
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*/
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struct file *fd_dfiles[NDFILE];
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char fd_dfileflags[NDFILE];
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};
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/*
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* Per-process open flags.
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*/
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#define UF_EXCLOSE 0x01 /* auto-close on exec */
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#define UF_MAPPED 0x02 /* mapped from device */
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/*
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* Storage required per open file descriptor.
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*/
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#define OFILESIZE (sizeof(struct file *) + sizeof(char))
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#ifdef KERNEL
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/*
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* Kernel global variables and routines.
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*/
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int fdalloc __P((struct proc *p, int want, int *result));
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int fdavail __P((struct proc *p, int n));
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int falloc __P((struct proc *p, struct file **resultfp, int *resultfd));
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struct filedesc *fdcopy __P((struct proc *p));
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void fdfree __P((struct proc *p));
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int dupfdopen __P((struct filedesc *fdp, int indx, int dfd, int mode,
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int error));
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#endif
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#endif /* !_SYS_FILEDESC_H_ */
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