blob: ca21a02bf10a1d3830944bb2ff460f4d4ced9c80 (
plain)
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
|
// SPDX-License-Identifier: Apache-2.0
/*
* Copyright (C) 2013 Intel Corporation
*
*/
#include <stdio.h>
#include <errno.h>
#include <poll.h>
#include "pollhandler.h"
/*
* Code that allows to poll multiply file descriptors for events
* File descriptors can be added and removed at runtime
*
* Call poll_register_fd function first to add file descriptors to monitor
* Then call poll_dispatch_loop that will poll all registered file descriptors
* as long as they are not unregistered.
*
* When event happen on given fd appropriate user supplied handler is called
*/
/* Maximum number of files to monitor */
#define MAX_OPEN_FD 10
/* Storage for pollfd structures for monitored file descriptors */
static struct pollfd fds[MAX_OPEN_FD];
static poll_handler fds_handler[MAX_OPEN_FD];
/* Number of registered file descriptors */
static int fds_count = 0;
/*
* Function polls file descriptor in loop and calls appropriate handler
* on event. Function returns when there is no more file descriptor to
* monitor
*/
void poll_dispatch_loop(void)
{
while (fds_count > 0) {
int i;
int cur_fds_count = fds_count;
int ready = poll(fds, fds_count, 1000);
for (i = 0; i < fds_count && ready > 0; ++i) {
if (fds[i].revents == 0)
continue;
fds_handler[i](fds + i);
ready--;
/*
* If handler was remove from table
* just skip the rest and poll again
* This is due to reordering of tables in
* register/unregister functions
*/
if (cur_fds_count != fds_count)
break;
}
}
}
/*
* Registers file descriptor to be monitored for events (see man poll(2))
* for events.
*
* return non negative value on success
* -EMFILE when there are to much descriptors
*/
int poll_register_fd(int fd, short events, poll_handler ph)
{
if (fds_count >= MAX_OPEN_FD)
return -EMFILE;
fds_handler[fds_count] = ph;
fds[fds_count].fd = fd;
fds[fds_count].events = events;
fds_count++;
return fds_count;
}
/*
* Unregisters file descriptor
* Both fd and ph must match previously registered data
*
* return 0 if unregister succeeded
* -EBADF if arguments do not match any register handler
*/
int poll_unregister_fd(int fd, poll_handler ph)
{
int i;
for (i = 0; i < fds_count; ++i) {
if (fds_handler[i] == ph && fds[i].fd == fd) {
fds_count--;
if (i < fds_count) {
fds[i].fd = fds[fds_count].fd;
fds[i].events = fds[fds_count].events;
fds_handler[i] = fds_handler[fds_count];
}
return 0;
}
}
return -EBADF;
}
|
