Annotation of kernel/bsd/sys/filedesc.h, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
                      3:  *
                      4:  * @APPLE_LICENSE_HEADER_START@
                      5:  * 
                      6:  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
                      7:  * Reserved.  This file contains Original Code and/or Modifications of
                      8:  * Original Code as defined in and that are subject to the Apple Public
                      9:  * Source License Version 1.1 (the "License").  You may not use this file
                     10:  * except in compliance with the License.  Please obtain a copy of the
                     11:  * License at http://www.apple.com/publicsource and read it before using
                     12:  * this file.
                     13:  * 
                     14:  * The Original Code and all software distributed under the License are
                     15:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
                     16:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
                     17:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
                     18:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
                     19:  * License for the specific language governing rights and limitations
                     20:  * under the License.
                     21:  * 
                     22:  * @APPLE_LICENSE_HEADER_END@
                     23:  */
                     24: 
                     25: /* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
                     26: /*
                     27:  * Copyright (c) 1990, 1993
                     28:  *     The Regents of the University of California.  All rights reserved.
                     29:  *
                     30:  * Redistribution and use in source and binary forms, with or without
                     31:  * modification, are permitted provided that the following conditions
                     32:  * are met:
                     33:  * 1. Redistributions of source code must retain the above copyright
                     34:  *    notice, this list of conditions and the following disclaimer.
                     35:  * 2. Redistributions in binary form must reproduce the above copyright
                     36:  *    notice, this list of conditions and the following disclaimer in the
                     37:  *    documentation and/or other materials provided with the distribution.
                     38:  * 3. All advertising materials mentioning features or use of this software
                     39:  *    must display the following acknowledgement:
                     40:  *     This product includes software developed by the University of
                     41:  *     California, Berkeley and its contributors.
                     42:  * 4. Neither the name of the University nor the names of its contributors
                     43:  *    may be used to endorse or promote products derived from this software
                     44:  *    without specific prior written permission.
                     45:  *
                     46:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     47:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     48:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     49:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     50:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     51:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     52:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     53:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     54:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     55:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     56:  * SUCH DAMAGE.
                     57:  *
                     58:  *     @(#)filedesc.h  8.1 (Berkeley) 6/2/93
                     59:  */
                     60: 
                     61: #ifndef _SYS_FILEDESC_H_
                     62: #define        _SYS_FILEDESC_H_
                     63: 
                     64: /*
                     65:  * This structure is used for the management of descriptors.  It may be
                     66:  * shared by multiple processes.
                     67:  *
                     68:  * A process is initially started out with NDFILE descriptors [XXXstored within
                     69:  * this structureXXX], selected to be enough for typical applications based on
                     70:  * the historical limit of 20 open files (and the usage of descriptors by
                     71:  * shells).  If these descriptors are exhausted, a larger descriptor table
                     72:  * may be allocated, up to a process' resource limit; [XXXthe internal arrays
                     73:  * are then unusedXXX].  The initial expansion is set to NDEXTENT; each time
                     74:  * it runs out, it is doubled until the resource limit is reached. NDEXTENT
                     75:  * should be selected to be the biggest multiple of OFILESIZE (see below)
                     76:  * that will fit in a power-of-two sized piece of memory.
                     77:  */
                     78: #define NDFILE         25              /* 125 bytes */
                     79: #define NDEXTENT       50              /* 250 bytes in 256-byte alloc. */ 
                     80: 
                     81: struct filedesc {
                     82:        struct  file **fd_ofiles;       /* file structures for open files */
                     83:        char    *fd_ofileflags;         /* per-process open file flags */
                     84:        struct  vnode *fd_cdir;         /* current directory */
                     85:        struct  vnode *fd_rdir;         /* root directory */
                     86:        int     fd_nfiles;              /* number of open files allocated */
                     87:        u_short fd_lastfile;            /* high-water mark of fd_ofiles */
                     88:        u_short fd_freefile;            /* approx. next free file */
                     89:        u_short fd_cmask;               /* mask for file creation */
                     90:        u_short fd_refcnt;              /* reference count */
                     91: };
                     92: 
                     93: /*
                     94:  * Per-process open flags.
                     95:  */
                     96: #define        UF_EXCLOSE      0x01            /* auto-close on exec */
                     97: #define        UF_MAPPED       0x02            /* mapped from device */
                     98: #define UF_RESERVED    0x04            /* open pending / in progress */
                     99: 
                    100: /*
                    101:  * Storage required per open file descriptor.
                    102:  */
                    103: #define OFILESIZE (sizeof(struct file *) + sizeof(char))
                    104: 
                    105: #ifdef _KERNEL
                    106: /*
                    107:  * Kernel global variables and routines.
                    108:  */
                    109: extern int     dupfdopen __P((struct filedesc *fdp,
                    110:                                int indx, int dfd, int mode, int error));
                    111: extern int     fdalloc __P((struct proc *p, int want, int *result));
                    112: extern void    fdrelse __P((struct proc *p, int fd));
                    113: extern int     fdavail __P((struct proc *p, int n));
                    114: extern int     fdgetf __P((struct proc *p, int fd, struct file **resultfp));
                    115: #define                fdfile(p, fd)                                   \
                    116:                        (&(p)->p_fd->fd_ofiles[(fd)])
                    117: #define                fdflags(p, fd)                                  \
                    118:                        (&(p)->p_fd->fd_ofileflags[(fd)])
                    119: extern int     falloc __P((struct proc *p,
                    120:                                struct file **resultfp, int *resultfd));
                    121: extern void    ffree __P((struct file *fp));
                    122: extern struct  filedesc *fdcopy __P((struct proc *p));
                    123: extern void    fdfree __P((struct proc *p));
                    124: extern void    fdexec __P((struct proc *p));
                    125: 
                    126: #endif /* _KERNEL */
                    127: 
                    128: #endif /* !_SYS_FILEDESC_H_ */

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