mirror of
https://github.com/yaakov-h/scream-driver.git
synced 2024-10-16 07:40:02 +00:00
100 lines
No EOL
2.3 KiB
C
100 lines
No EOL
2.3 KiB
C
#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/cdev.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/uaccess.h>
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MODULE_AUTHOR("Yaakov");
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MODULE_DESCRIPTION("Scream Device");
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MODULE_LICENSE("GPL");
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#define DEVICE_NAME "scream_device"
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#define CLASS_NAME "scream_class"
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static int major_number;
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static struct class* scream_class = NULL;
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static struct device* scream_device = NULL;
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static struct cdev scream_cdev;
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static int scream_device_open(struct inode*, struct file*);
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static int scream_device_release(struct inode*, struct file*);
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static ssize_t scream_device_read(struct file*, char*, size_t, loff_t*);
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static const struct file_operations scream_fops = {
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.owner = THIS_MODULE,
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.open = scream_device_open,
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.read = scream_device_read,
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.release = scream_device_release,
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};
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static int __init scream_module_init(void)
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{
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int err;
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dev_t dev;
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err = alloc_chrdev_region(&dev, 0, 1, DEVICE_NAME);
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major_number = MAJOR(dev);
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scream_class = class_create(CLASS_NAME);
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cdev_init(&scream_cdev, &scream_fops);
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scream_cdev.owner = THIS_MODULE;
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cdev_add(&scream_cdev, MKDEV(major_number, 0), 1);
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device_create(scream_class, NULL, MKDEV(major_number, 0), NULL, DEVICE_NAME);
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return 0;
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}
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static void __exit scream_module_exit(void)
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{
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device_destroy(scream_class, MKDEV(major_number, 0));
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class_unregister(scream_class);
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class_destroy(scream_class);
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unregister_chrdev_region(MKDEV(major_number, 0), MINORMASK);
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}
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static int scream_device_open(struct inode *inode, struct file *file)
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{
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printk(KERN_INFO "[scream] Device open\n");
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return 0;
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}
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static int scream_device_release(struct inode *inode, struct file *file)
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{
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printk(KERN_INFO "[scream] Device close\n");
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return 0;
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}
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static ssize_t scream_device_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
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{
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uint8_t rand;
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for (size_t i = 0; i < count; i++)
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{
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get_random_bytes(&rand, sizeof(rand));
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char value;
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if (rand > 200) {
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value = 'A';
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} else {
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value = 'a';
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}
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if (copy_to_user(buf + i, &value, 1)) {
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return -EFAULT;
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}
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}
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return count;
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}
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module_init(scream_module_init);
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module_exit(scream_module_exit); |