Annotation of sys/sys/filedesc.h, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: filedesc.h,v 1.19 2004/07/22 06:11:10 tedu Exp $ */
2: /* $NetBSD: filedesc.h,v 1.14 1996/04/09 20:55:28 cgd Exp $ */
3:
4: /*
5: * Copyright (c) 1990, 1993
6: * The Regents of the University of California. All rights reserved.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: * 3. Neither the name of the University nor the names of its contributors
17: * may be used to endorse or promote products derived from this software
18: * without specific prior written permission.
19: *
20: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30: * SUCH DAMAGE.
31: *
32: * @(#)filedesc.h 8.1 (Berkeley) 6/2/93
33: */
34:
35: #include <sys/rwlock.h>
36: /*
37: * This structure is used for the management of descriptors. It may be
38: * shared by multiple processes.
39: *
40: * A process is initially started out with NDFILE descriptors stored within
41: * this structure, selected to be enough for typical applications based on
42: * the historical limit of 20 open files (and the usage of descriptors by
43: * shells). If these descriptors are exhausted, a larger descriptor table
44: * may be allocated, up to a process' resource limit; the internal arrays
45: * are then unused. The initial expansion is set to NDEXTENT; each time
46: * it runs out, it is doubled until the resource limit is reached. NDEXTENT
47: * should be selected to be the biggest multiple of OFILESIZE (see below)
48: * that will fit in a power-of-two sized piece of memory.
49: */
50: #define NDFILE 20
51: #define NDEXTENT 50 /* 250 bytes in 256-byte alloc. */
52: #define NDENTRIES 32 /* 32 fds per entry */
53: #define NDENTRYMASK (NDENTRIES - 1)
54: #define NDENTRYSHIFT 5 /* bits per entry */
55: #define NDREDUCE(x) (((x) + NDENTRIES - 1) >> NDENTRYSHIFT)
56: #define NDHISLOTS(x) (NDREDUCE(NDREDUCE(x)))
57: #define NDLOSLOTS(x) (NDHISLOTS(x) << NDENTRYSHIFT)
58:
59: struct filedesc {
60: struct file **fd_ofiles; /* file structures for open files */
61: char *fd_ofileflags; /* per-process open file flags */
62: struct vnode *fd_cdir; /* current directory */
63: struct vnode *fd_rdir; /* root directory */
64: int fd_nfiles; /* number of open files allocated */
65: u_int *fd_himap; /* each bit points to 32 fds */
66: u_int *fd_lomap; /* bitmap of free fds */
67: int fd_lastfile; /* high-water mark of fd_ofiles */
68: int fd_freefile; /* approx. next free file */
69: u_short fd_cmask; /* mask for file creation */
70: u_short fd_refcnt; /* reference count */
71: struct rwlock fd_lock; /* lock for the file descs */
72:
73: int fd_knlistsize; /* size of knlist */
74: struct klist *fd_knlist; /* list of attached knotes */
75: u_long fd_knhashmask; /* size of knhash */
76: struct klist *fd_knhash; /* hash table for attached knotes */
77: };
78:
79: /*
80: * Basic allocation of descriptors:
81: * one of the above, plus arrays for NDFILE descriptors.
82: */
83: struct filedesc0 {
84: struct filedesc fd_fd;
85: /*
86: * These arrays are used when the number of open files is
87: * <= NDFILE, and are then pointed to by the pointers above.
88: */
89: struct file *fd_dfiles[NDFILE];
90: char fd_dfileflags[NDFILE];
91: /*
92: * There arrays are used when the number of open files is
93: * <= 1024, and are then pointed to by the pointers above.
94: */
95: u_int fd_dhimap[NDENTRIES >> NDENTRYSHIFT];
96: u_int fd_dlomap[NDENTRIES];
97: };
98:
99: /*
100: * Per-process open flags.
101: */
102: #define UF_EXCLOSE 0x01 /* auto-close on exec */
103:
104: /*
105: * Storage required per open file descriptor.
106: */
107: #define OFILESIZE (sizeof(struct file *) + sizeof(char))
108:
109: #ifdef _KERNEL
110: /*
111: * Kernel global variables and routines.
112: */
113: void filedesc_init(void);
114: int dupfdopen(struct filedesc *fdp, int indx, int dfd, int mode,
115: int error);
116: int fdalloc(struct proc *p, int want, int *result);
117: void fdexpand(struct proc *);
118: int falloc(struct proc *p, struct file **resultfp, int *resultfd);
119: struct filedesc *fdinit(struct proc *p);
120: struct filedesc *fdshare(struct proc *p);
121: struct filedesc *fdcopy(struct proc *p);
122: void fdfree(struct proc *p);
123: int fdrelease(struct proc *p, int);
124: void fdremove(struct filedesc *, int);
125: void fdcloseexec(struct proc *);
126: struct file *fd_getfile(struct filedesc *, int fd);
127:
128: int closef(struct file *, struct proc *);
129: int getsock(struct filedesc *, int, struct file **);
130:
131: #define fdplock(fdp) rw_enter_write(&(fdp)->fd_lock)
132: #define fdpunlock(fdp) rw_exit_write(&(fdp)->fd_lock)
133: #endif
CVSweb
![[BACK]](/icons/back.gif){kind=icon}
Return to filedesc.h CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / sys / sys