bsd/sys/filedesc.h

   1 /*
   2  * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  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 #include <sys/appleapiopts.h>
  65
  66 #ifdef __APPLE_API_UNSTABLE
  67 /*
  68  * This structure is used for the management of descriptors.  It may be
  69  * shared by multiple processes.
  70  *
  71  * A process is initially started out with NDFILE descriptors [XXXstored within
  72  * this structureXXX], selected to be enough for typical applications based on
  73  * the historical limit of 20 open files (and the usage of descriptors by
  74  * shells).  If these descriptors are exhausted, a larger descriptor table
  75  * may be allocated, up to a process' resource limit; [XXXthe internal arrays
  76  * are then unusedXXX].  The initial expansion is set to NDEXTENT; each time
  77  * it runs out, it is doubled until the resource limit is reached. NDEXTENT
  78  * should be selected to be the biggest multiple of OFILESIZE (see below)
  79  * that will fit in a power-of-two sized piece of memory.
  80  */
  81 #define NDFILE          25              /* 125 bytes */
  82 #define NDEXTENT        50              /* 250 bytes in 256-byte alloc. */
  83
  84 struct klist;
  85
  86 struct filedesc {
  87         struct  file **fd_ofiles;       /* file structures for open files */
  88         char    *fd_ofileflags;         /* per-process open file flags */
  89         struct  vnode *fd_cdir;         /* current directory */
  90         struct  vnode *fd_rdir;         /* root directory */
  91         int     fd_nfiles;              /* number of open files allocated */
  92         u_short fd_lastfile;            /* high-water mark of fd_ofiles */
  93         u_short fd_freefile;            /* approx. next free file */
  94         u_short fd_cmask;               /* mask for file creation */
  95         u_short fd_refcnt;              /* reference count */
  96
  97         int     fd_knlistsize;          /* size of knlist */
  98         struct  klist *fd_knlist;       /* list of attached knotes */
  99         u_long  fd_knhashmask;          /* size of knhash */
 100         struct  klist *fd_knhash;       /* hash table for attached knotes */
 101 };
 102
 103 /*
 104  * Per-process open flags.
 105  */
 106 #define UF_EXCLOSE      0x01            /* auto-close on exec */
 107 #define UF_MAPPED       0x02            /* mapped from device */
 108 #define UF_RESERVED     0x04            /* open pending / in progress */
 109
 110 /*
 111  * Storage required per open file descriptor.
 112  */
 113 #define OFILESIZE (sizeof(struct file *) + sizeof(char))
 114
 115 #ifdef KERNEL
 116 /*
 117  * Kernel global variables and routines.
 118  */
 119 extern int      dupfdopen __P((struct filedesc *fdp,
 120                                 int indx, int dfd, int mode, int error));
 121 extern int      fdalloc __P((struct proc *p, int want, int *result));
 122 extern void     fdrelse __P((struct proc *p, int fd));
 123 extern int      fdavail __P((struct proc *p, int n));
 124 extern int      fdgetf __P((struct proc *p, int fd, struct file **resultfp));
 125 #define         fdfile(p, fd)                                   \
 126                         (&(p)->p_fd->fd_ofiles[(fd)])
 127 #define         fdflags(p, fd)                                  \
 128                         (&(p)->p_fd->fd_ofileflags[(fd)])
 129 extern int      falloc __P((struct proc *p,
 130                                 struct file **resultfp, int *resultfd));
 131 extern void     ffree __P((struct file *fp));
 132
 133 #ifdef __APPLE_API_PRIVATE
 134 extern struct   filedesc *fdcopy __P((struct proc *p));
 135 extern void     fdfree __P((struct proc *p));
 136 extern void     fdexec __P((struct proc *p));
 137 #endif /* __APPLE_API_PRIVATE */
 138
 139 #endif /* KERNEL */
 140
 141 #endif /* __APPLE_API_UNSTABLE */
 142
 143 #endif /* !_SYS_FILEDESC_H_ */