H4CK3R 4/hacker04/04_HACK04.ISO/darwin/darwinx86.iso/usr/include/sys/filedesc.h

C/C++ Source or Header | 2001-09-30 | 5.3 KB | 126 lines

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 *
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 *
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 *
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
/*
 * 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
 */

#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 [XXXstored within
 * this structureXXX], 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; [XXXthe internal arrays
 * are then unusedXXX].  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        25        /* 125 bytes */
#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 */
};

/*
 * Per-process open flags.
 */
#define    UF_EXCLOSE     0x01        /* auto-close on exec */
#define    UF_MAPPED     0x02        /* mapped from device */
#define UF_RESERVED    0x04        /* open pending / in progress */

/*
 * Storage required per open file descriptor.
 */
#define OFILESIZE (sizeof(struct file *) + sizeof(char))

#ifdef KERNEL
/*
 * Kernel global variables and routines.
 */
extern int    dupfdopen __P((struct filedesc *fdp,
                int indx, int dfd, int mode, int error));
extern int    fdalloc __P((struct proc *p, int want, int *result));
extern void    fdrelse __P((struct proc *p, int fd));
extern int    fdavail __P((struct proc *p, int n));
extern int    fdgetf __P((struct proc *p, int fd, struct file **resultfp));
#define        fdfile(p, fd)                    \
            (&(p)->p_fd->fd_ofiles[(fd)])
#define        fdflags(p, fd)                    \
            (&(p)->p_fd->fd_ofileflags[(fd)])
extern int    falloc __P((struct proc *p,
                struct file **resultfp, int *resultfd));
extern void    ffree __P((struct file *fp));
extern struct    filedesc *fdcopy __P((struct proc *p));
extern void    fdfree __P((struct proc *p));
extern void    fdexec __P((struct proc *p));

#endif /* KERNEL */

#endif /* !_SYS_FILEDESC_H_ */