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
|
#ifndef _LINUX_POLL_H
#define _LINUX_POLL_H
#include <asm/poll.h>
#ifdef __KERNEL__
#include <linux/wait.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <asm/uaccess.h>
struct poll_table_entry {
struct file * filp;
struct wait_queue wait;
struct wait_queue ** wait_address;
};
typedef struct poll_table_struct {
struct poll_table_struct * next;
unsigned int nr;
struct poll_table_entry * entry;
} poll_table;
#define __MAX_POLL_TABLE_ENTRIES ((PAGE_SIZE - sizeof (poll_table)) / sizeof (struct poll_table_entry))
extern void __pollwait(struct file * filp, struct wait_queue ** wait_address, poll_table *p);
extern inline void poll_wait(struct file * filp, struct wait_queue ** wait_address, poll_table *p)
{
if (p && wait_address)
__pollwait(filp, wait_address, p);
}
/*
* For the kernel fd_set we use a fixed set-size for allocation purposes.
* This set-size doesn't necessarily bear any relation to the size the user
* uses, but should preferably obviously be larger than any possible user
* size (NR_OPEN bits).
*
* We need 6 bitmaps (in/out/ex for both incoming and outgoing), and we
* allocate one page for all the bitmaps. Thus we have 8*PAGE_SIZE bits,
* to be divided by 6. And we'd better make sure we round to a full
* long-word (in fact, we'll round to 64 bytes).
*/
#define KFDS_64BLOCK ((PAGE_SIZE/(6*64))*64)
#define KFDS_NR (KFDS_64BLOCK*8 > NR_OPEN ? NR_OPEN : KFDS_64BLOCK*8)
typedef unsigned long kernel_fd_set[KFDS_NR/__NFDBITS];
/*
* Scalable version of the fd_set.
*/
typedef struct {
unsigned long *in, *out, *ex;
unsigned long *res_in, *res_out, *res_ex;
} fd_set_bits;
/*
* How many longwords for "nr" bits?
*/
#define FDS_BITPERLONG (8*sizeof(long))
#define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
#define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long))
/*
* We do a VERIFY_WRITE here even though we are only reading this time:
* we'll write to it eventually..
*
* Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
*/
static inline
int get_fd_set(unsigned long nr, void *ufdset, unsigned long *fdset)
{
nr = FDS_BYTES(nr);
if (ufdset) {
int error;
error = verify_area(VERIFY_WRITE, ufdset, nr);
if (!error && __copy_from_user(fdset, ufdset, nr))
error = -EFAULT;
return error;
}
memset(fdset, 0, nr);
return 0;
}
static inline
void set_fd_set(unsigned long nr, void *ufdset, unsigned long *fdset)
{
if (ufdset)
__copy_to_user(ufdset, fdset, FDS_BYTES(nr));
}
static inline
void zero_fd_set(unsigned long nr, unsigned long *fdset)
{
memset(fdset, 0, FDS_BYTES(nr));
}
extern int do_select(int n, fd_set_bits *fds, long *timeout);
#endif /* KERNEL */
#endif /* _LINUX_POLL_H */
|
