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1.1 root 1: /*
2: * Copyright (c) 1990 The Regents of the University of California.
3: * All rights reserved.
4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: * 3. All advertising materials mentioning features or use of this software
14: * must display the following acknowledgement:
15: * This product includes software developed by the University of
16: * California, Berkeley and its contributors.
17: * 4. Neither the name of the University nor the names of its contributors
18: * may be used to endorse or promote products derived from this software
19: * without specific prior written permission.
20: *
21: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31: * SUCH DAMAGE.
32: *
1.1.1.2 ! root 33: * from: @(#)filedesc.h 7.4 (Berkeley) 5/4/91
! 34: * filedesc.h,v 1.3 1993/05/20 16:22:17 cgd Exp
1.1 root 35: */
36:
1.1.1.2 ! root 37: #ifndef _SYS_FILEDESC_H_
! 38: #define _SYS_FILEDESC_H_
! 39:
1.1 root 40: /*
41: * This structure is used for the management of descriptors. It may be
42: * shared by multiple processes.
43: *
44: * A process is initially started out with NDFILE descriptors stored within
45: * this structure, selected to be enough for typical applications based on
46: * the historical limit of 20 open files (and the usage of descriptors by
47: * shells). If these descriptors are exhausted, a larger descriptor table
48: * may be allocated, up to a process' resource limit; the internal arrays
49: * are then unused. The initial expansion is set to NDEXTENT; each time
50: * it runs out, it is doubled until the resource limit is reached. NDEXTENT
51: * should be selected to be the biggest multiple of OFILESIZE (see below)
52: * that will fit in a power-of-two sized piece of memory.
53: */
54: #define NDFILE 20
55: #define NDEXTENT 50 /* 250 bytes in 256-byte alloc. */
56:
57: struct filedesc {
58: struct file **fd_ofiles; /* file structures for open files */
59: char *fd_ofileflags; /* per-process open file flags */
60: struct vnode *fd_cdir; /* current directory */
61: struct vnode *fd_rdir; /* root directory */
62: int fd_nfiles; /* number of open files allocated */
63: u_short fd_lastfile; /* high-water mark of fd_ofiles */
64: u_short fd_freefile; /* approx. next free file */
65: u_short fd_cmask; /* mask for file creation */
66: u_short fd_refcnt; /* reference count */
67: };
68:
69: /*
70: * Basic allocation of descriptors:
71: * one of the above, plus arrays for NDFILE descriptors.
72: */
73: struct filedesc0 {
74: struct filedesc fd_fd;
75: /*
76: * These arrays are used when the number of open files is
77: * <= NDFILE, and are then pointed to by the pointers above.
78: */
79: struct file *fd_dfiles[NDFILE];
80: char fd_dfileflags[NDFILE];
81: };
82:
83: /*
84: * Per-process open flags.
85: */
86: #define UF_EXCLOSE 0x01 /* auto-close on exec */
87: #define UF_MAPPED 0x02 /* mapped from device */
88:
89: /*
90: * Storage required per open file descriptor.
91: */
92: #define OFILESIZE (sizeof(struct file *) + sizeof(char))
93:
94: #ifdef KERNEL
95: /*
96: * Kernel global variables and routines.
97: */
98: int fdalloc __P((struct proc *p, int want, int *result));
99: int fdavail __P((struct proc *p, int n));
100: int falloc __P((struct proc *p, struct file **resultfp, int *resultfd));
101: struct filedesc *fdcopy __P((struct proc *p));
102: void fdfree __P((struct proc *p));
103: #endif
1.1.1.2 ! root 104:
! 105: #endif /* !_SYS_FILEDESC_H_ */
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