-
Notifications
You must be signed in to change notification settings - Fork 0
/
ballmer.c
69 lines (58 loc) · 1.95 KB
/
ballmer.c
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
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#define DEVICE_NAME "ballmer"
#define CLASS_NAME "ballmer"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rachel Snijders");
MODULE_DESCRIPTION("Get inspired by our lord and savior, Steve Ballmer.");
MODULE_VERSION("0.1");
static int majorNumber;
static struct class* ballmerClass = NULL;
static struct cdev ballmer_cdev;
static ssize_t dev_read(struct file *filep, char *buffer, size_t len, loff_t *offset) {
int errors = 0;
char *message = "Developers, Developers, Developers\n";
int message_len = strlen(message);
errors = copy_to_user(buffer, message, message_len);
return errors == 0 ? message_len : -EFAULT;
}
static struct file_operations dev_fops = {
.owner = THIS_MODULE,
.read = dev_read,
};
static int __init ballmer_init(void) {
majorNumber = register_chrdev(0, DEVICE_NAME, &dev_fops);
if (majorNumber<0){
return majorNumber;
}
ballmerClass = class_create(THIS_MODULE, CLASS_NAME);
if (IS_ERR(ballmerClass)){
unregister_chrdev(majorNumber, DEVICE_NAME);
return PTR_ERR(ballmerClass);
}
if (!device_create(ballmerClass, NULL, MKDEV(majorNumber, 0), NULL, DEVICE_NAME)){
class_destroy(ballmerClass);
unregister_chrdev(majorNumber, DEVICE_NAME);
return -1;
}
cdev_init(&ballmer_cdev, &dev_fops);
if (cdev_add(&ballmer_cdev, MKDEV(majorNumber, 0), 1) == -1) {
device_destroy(ballmerClass, MKDEV(majorNumber, 0));
class_destroy(ballmerClass);
unregister_chrdev(majorNumber, DEVICE_NAME);
return -1;
}
printk(KERN_INFO "Ballmer module loaded.\n");
return 0;
}
static void __exit ballmer_exit(void) {
device_destroy(ballmerClass, MKDEV(majorNumber, 0));
class_destroy(ballmerClass);
unregister_chrdev(majorNumber, DEVICE_NAME);
printk(KERN_INFO "Ballmer module removed.\n");
}
module_init(ballmer_init);
module_exit(ballmer_exit);