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#include <linux/module.h> #include <linux/fs.h> #include <linux/cdev.h> #include <linux/device.h> #define MODULE_NAME "my_driver" #define ENCRYPT_MINOR 0 #define DECRYPT_MINOR 1 static int major_number; static struct class *my_class = NULL; static struct cdev my_cdev; static int my_open(struct inode *inode, struct file *file) { // Implement open operation return 0; } static int my_release(struct inode *inode, struct file *file) { // Implement release operation return 0; } static ssize_t my_read(struct file *file, char __user *user_buffer, size_t count, loff_t *offset) { // Implement read operation return 0; } static ssize_t my_write(struct file *file, const char __user *user_buffer, size_t count, loff_t *offset) { // Implement write operation return 0; } static struct file_operations my_fops = { .owner = THIS_MODULE, .open = my_open, .release = my_release, .read = my_read, .write = my_write, }; static int __init my_init(void) { // Dynamically allocate a major number if ((major_number = register_chrdev(0, MODULE_NAME, &my_fops)) < 0) { printk(KERN_ALERT "Failed to register a major number\n"); return major_number; } // Create a class my_class = class_create(THIS_MODULE, MODULE_NAME); if (IS_ERR(my_class)) { unregister_chrdev(major_number, MODULE_NAME); printk(KERN_ALERT "Failed to register device class\n"); return PTR_ERR(my_class); } // Create /dev/encrypt node device_create(my_class, NULL, MKDEV(major_number, ENCRYPT_MINOR), NULL, "encrypt"); // Create /dev/decrypt node device_create(my_class, NULL, MKDEV(major_number, DECRYPT_MINOR), NULL, "decrypt"); // Initialize the character device cdev_init(&my_cdev, &my_fops); // Add the character device to the kernel for /dev/encrypt if (cdev_add(&my_cdev, MKDEV(major_number, ENCRYPT_MINOR), 1) < 0) { device_destroy(my_class, MKDEV(major_number, ENCRYPT_MINOR)); class_destroy(my_class); unregister_chrdev(major_number, MODULE_NAME); printk(KERN_ALERT "Failed to add the device to the kernel\n"); return -1; } // Add the character device to the kernel for /dev/decrypt if (cdev_add(&my_cdev, MKDEV(major_number, DECRYPT_MINOR), 1) < 0) { device_destroy(my_class, MKDEV(major_number, DECRYPT_MINOR)); class_destroy(my_class); unregister_chrdev(major_number, MODULE_NAME); printk(KERN_ALERT "Failed to add the device to the kernel\n"); return -1; } printk(KERN_INFO "Module loaded with major number %d\n", major_number); return 0; } static void __exit my_exit(void) { // Clean up the module device_destroy(my_class, MKDEV(major_number, ENCRYPT_MINOR)); device_destroy(my_class, MKDEV(major_number, DECRYPT_MINOR)); class_unregister(my_class); class_destroy(my_class); unregister_chrdev(major_number, MODULE_NAME); printk(KERN_INFO "Module unloaded\n"); } module_init(my_init); module_exit(my_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Your Name"); MODULE_DESCRIPTION("Simple character device driver with dynamic major number");
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