bsd/sys/filedesc.h

   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_ */