Annotation of XNU/bsd/sys/filedesc.h, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * The contents of this file constitute Original Code as defined in and
        !             7:  * are subject to the Apple Public Source License Version 1.1 (the
        !             8:  * "License").  You may not use this file except in compliance with the
        !             9:  * License.  Please obtain a copy of the License at
        !            10:  * http://www.apple.com/publicsource and read it before using this file.
        !            11:  * 
        !            12:  * This Original Code and all software distributed under the License are
        !            13:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            14:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            15:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            16:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            17:  * License for the specific language governing rights and limitations
        !            18:  * under the License.
        !            19:  * 
        !            20:  * @APPLE_LICENSE_HEADER_END@
        !            21:  */
        !            22: /* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
        !            23: /*
        !            24:  * Copyright (c) 1990, 1993
        !            25:  *     The Regents of the University of California.  All rights reserved.
        !            26:  *
        !            27:  * Redistribution and use in source and binary forms, with or without
        !            28:  * modification, are permitted provided that the following conditions
        !            29:  * are met:
        !            30:  * 1. Redistributions of source code must retain the above copyright
        !            31:  *    notice, this list of conditions and the following disclaimer.
        !            32:  * 2. Redistributions in binary form must reproduce the above copyright
        !            33:  *    notice, this list of conditions and the following disclaimer in the
        !            34:  *    documentation and/or other materials provided with the distribution.
        !            35:  * 3. All advertising materials mentioning features or use of this software
        !            36:  *    must display the following acknowledgement:
        !            37:  *     This product includes software developed by the University of
        !            38:  *     California, Berkeley and its contributors.
        !            39:  * 4. Neither the name of the University nor the names of its contributors
        !            40:  *    may be used to endorse or promote products derived from this software
        !            41:  *    without specific prior written permission.
        !            42:  *
        !            43:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            44:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            45:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            46:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            47:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            48:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            49:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            50:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            51:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            52:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            53:  * SUCH DAMAGE.
        !            54:  *
        !            55:  *     @(#)filedesc.h  8.1 (Berkeley) 6/2/93
        !            56:  */
        !            57: 
        !            58: #ifndef _SYS_FILEDESC_H_
        !            59: #define        _SYS_FILEDESC_H_
        !            60: 
        !            61: /*
        !            62:  * This structure is used for the management of descriptors.  It may be
        !            63:  * shared by multiple processes.
        !            64:  *
        !            65:  * A process is initially started out with NDFILE descriptors [XXXstored within
        !            66:  * this structureXXX], selected to be enough for typical applications based on
        !            67:  * the historical limit of 20 open files (and the usage of descriptors by
        !            68:  * shells).  If these descriptors are exhausted, a larger descriptor table
        !            69:  * may be allocated, up to a process' resource limit; [XXXthe internal arrays
        !            70:  * are then unusedXXX].  The initial expansion is set to NDEXTENT; each time
        !            71:  * it runs out, it is doubled until the resource limit is reached. NDEXTENT
        !            72:  * should be selected to be the biggest multiple of OFILESIZE (see below)
        !            73:  * that will fit in a power-of-two sized piece of memory.
        !            74:  */
        !            75: #define NDFILE         25              /* 125 bytes */
        !            76: #define NDEXTENT       50              /* 250 bytes in 256-byte alloc. */ 
        !            77: 
        !            78: struct filedesc {
        !            79:        struct  file **fd_ofiles;       /* file structures for open files */
        !            80:        char    *fd_ofileflags;         /* per-process open file flags */
        !            81:        struct  vnode *fd_cdir;         /* current directory */
        !            82:        struct  vnode *fd_rdir;         /* root directory */
        !            83:        int     fd_nfiles;              /* number of open files allocated */
        !            84:        u_short fd_lastfile;            /* high-water mark of fd_ofiles */
        !            85:        u_short fd_freefile;            /* approx. next free file */
        !            86:        u_short fd_cmask;               /* mask for file creation */
        !            87:        u_short fd_refcnt;              /* reference count */
        !            88: };
        !            89: 
        !            90: /*
        !            91:  * Per-process open flags.
        !            92:  */
        !            93: #define        UF_EXCLOSE      0x01            /* auto-close on exec */
        !            94: #define        UF_MAPPED       0x02            /* mapped from device */
        !            95: #define UF_RESERVED    0x04            /* open pending / in progress */
        !            96: 
        !            97: /*
        !            98:  * Storage required per open file descriptor.
        !            99:  */
        !           100: #define OFILESIZE (sizeof(struct file *) + sizeof(char))
        !           101: 
        !           102: #ifdef KERNEL
        !           103: /*
        !           104:  * Kernel global variables and routines.
        !           105:  */
        !           106: extern int     dupfdopen __P((struct filedesc *fdp,
        !           107:                                int indx, int dfd, int mode, int error));
        !           108: extern int     fdalloc __P((struct proc *p, int want, int *result));
        !           109: extern void    fdrelse __P((struct proc *p, int fd));
        !           110: extern int     fdavail __P((struct proc *p, int n));
        !           111: extern int     fdgetf __P((struct proc *p, int fd, struct file **resultfp));
        !           112: #define                fdfile(p, fd)                                   \
        !           113:                        (&(p)->p_fd->fd_ofiles[(fd)])
        !           114: #define                fdflags(p, fd)                                  \
        !           115:                        (&(p)->p_fd->fd_ofileflags[(fd)])
        !           116: extern int     falloc __P((struct proc *p,
        !           117:                                struct file **resultfp, int *resultfd));
        !           118: extern void    ffree __P((struct file *fp));
        !           119: extern struct  filedesc *fdcopy __P((struct proc *p));
        !           120: extern void    fdfree __P((struct proc *p));
        !           121: extern void    fdexec __P((struct proc *p));
        !           122: 
        !           123: #endif /* KERNEL */
        !           124: 
        !           125: #endif /* !_SYS_FILEDESC_H_ */

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