1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
/*
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)filedesc.h 8.1 (Berkeley) 6/2/93
* $FreeBSD$
*/
#ifndef _SYS_FILEDESC_H_
#define _SYS_FILEDESC_H_
#include <sys/queue.h>
#include <sys/_lock.h>
#include <sys/_mutex.h>
#include <machine/_limits.h>
/*
* This structure is used for the management of descriptors. It may be
* shared by multiple processes.
*
* A process is initially started out with NDFILE descriptors stored within
* this structure, selected to be enough for typical applications based on
* the historical limit of 20 open files (and the usage of descriptors by
* shells). If these descriptors are exhausted, a larger descriptor table
* may be allocated, up to a process' resource limit; the internal arrays
* are then unused.
*/
#define NDFILE 20
#define NDSLOTTYPE u_long
#define NDSLOTSIZE sizeof(NDSLOTTYPE)
#define NDENTRIES (NDSLOTSIZE * __CHAR_BIT)
#define NDSLOT(x) ((x) / NDENTRIES)
#define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES))
#define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES)
struct filedesc {
struct file **fd_ofiles; /* file structures for open files */
char *fd_ofileflags; /* per-process open file flags */
struct vnode *fd_cdir; /* current directory */
struct vnode *fd_rdir; /* root directory */
struct vnode *fd_jdir; /* jail root directory */
int fd_nfiles; /* number of open files allocated */
NDSLOTTYPE *fd_map; /* bitmap of free fds */
int fd_lastfile; /* high-water mark of fd_ofiles */
int fd_freefile; /* approx. next free file */
u_short fd_cmask; /* mask for file creation */
u_short fd_refcnt; /* reference count */
int fd_knlistsize; /* size of knlist */
struct klist *fd_knlist; /* list of attached knotes */
u_long fd_knhashmask; /* size of knhash */
struct klist *fd_knhash; /* hash table for attached knotes */
struct mtx fd_mtx; /* protects members of this struct */
int fd_holdleaderscount; /* block fdfree() for shared close() */
int fd_holdleaderswakeup; /* fdfree() needs wakeup */
};
/*
* Basic allocation of descriptors:
* one of the above, plus arrays for NDFILE descriptors.
*/
struct filedesc0 {
struct filedesc fd_fd;
/*
* These arrays are used when the number of open files is
* <= NDFILE, and are then pointed to by the pointers above.
*/
struct file *fd_dfiles[NDFILE];
char fd_dfileflags[NDFILE];
NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)];
};
/*
* Structure to keep track of (process leader, struct fildedesc) tuples.
* Each process has a pointer to such a structure when detailed tracking
* is needed, e.g., when rfork(RFPROC | RFMEM) causes a file descriptor
* table to be shared by processes having different "p_leader" pointers
* and thus distinct POSIX style locks.
*
* fdl_refcount and fdl_holdcount are protected by struct filedesc mtx.
*/
struct filedesc_to_leader {
int fdl_refcount; /* references from struct proc */
int fdl_holdcount; /* temporary hold during closef */
int fdl_wakeup; /* fdfree() waits on closef() */
struct proc *fdl_leader; /* owner of POSIX locks */
/* Circular list: */
struct filedesc_to_leader *fdl_prev;
struct filedesc_to_leader *fdl_next;
};
/*
* Per-process open flags.
*/
#define UF_EXCLOSE 0x01 /* auto-close on exec */
/*
* Storage required per open file descriptor.
*/
#define OFILESIZE (sizeof(struct file *) + sizeof(char))
#ifdef _KERNEL
/* Lock a file descriptor table. */
#define FILEDESC_LOCK(fd) mtx_lock(&(fd)->fd_mtx)
#define FILEDESC_UNLOCK(fd) mtx_unlock(&(fd)->fd_mtx)
#define FILEDESC_LOCKED(fd) mtx_owned(&(fd)->fd_mtx)
#define FILEDESC_LOCK_ASSERT(fd, type) mtx_assert(&(fd)->fd_mtx, (type))
#define FILEDESC_LOCK_DESC "filedesc structure"
struct thread;
int closef(struct file *fp, struct thread *td);
int dupfdopen(struct thread *td, struct filedesc *fdp, int indx, int dfd,
int mode, int error);
int falloc(struct thread *td, struct file **resultfp, int *resultfd);
int fdalloc(struct thread *td, int minfd, int *result);
int fdavail(struct thread *td, int n);
int fdcheckstd(struct thread *td);
void fdcloseexec(struct thread *td);
struct filedesc *fdcopy(struct filedesc *fdp);
void fdfree(struct thread *td);
struct filedesc *fdinit(struct filedesc *fdp);
struct filedesc *fdshare(struct filedesc *fdp);
void fdunused(struct filedesc *fdp, int fd);
void fdused(struct filedesc *fdp, int fd);
void ffree(struct file *fp);
struct filedesc_to_leader *
filedesc_to_leader_alloc(struct filedesc_to_leader *old,
struct filedesc *fdp, struct proc *leader);
int getvnode(struct filedesc *fdp, int fd, struct file **fpp);
void setugidsafety(struct thread *td);
static __inline struct file *
fget_locked(struct filedesc *fdp, int fd)
{
return (fd < 0 || fd >= fdp->fd_nfiles ? NULL : fdp->fd_ofiles[fd]);
}
extern struct mtx fdesc_mtx;
#endif /* _KERNEL */
#endif /* !_SYS_FILEDESC_H_ */
|