initial commit uwu

.gitignore

@@ -0,0 +1,7 @@
+*.cmd
+*.ko
+*.mod
+*.mod.c
+*.o
+Module.symvers
+modules.order

Makefile

@@ -0,0 +1,24 @@
+
+DEBUG ?= n
+ifeq ($(DEBUG),y)
+	EXTRA_CFLAGS += -Og -g -DDEBUG
+else
+	EXTRA_CFLAGS += -O2
+endif
+
+EXTRA_CFLAGS += -I$(PWD)/include
+
+obj-m += keymash.o
+
+keymash-sources = src/keymash.c
+
+keymash-objs = $(keymash-sources:.c=.o)
+
+keymash.ko:
+	make -C "/lib/modules/$(shell uname -r)/build" M="$(PWD)" modules
+
+clean:
+	make -C "/lib/modules/$(shell uname -r)/build" M="$(PWD)" clean
+
+all: keymash.ko
+

src/keymash.c

@@ -0,0 +1,135 @@
+#include <linux/cdev.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("fef <owo@fef.moe>");
+MODULE_DESCRIPTION("gay keymash character device driver");
+MODULE_VERSION("0.1.0");
+
+#define keymash_debug(msg, ...) printk(KERN_DEBUG "keymash: " msg, ##__VA_ARGS__)
+#define keymash_info(msg, ...) printk(KERN_INFO "keymash: " msg, ##__VA_ARGS__)
+#define keymash_warn(msg, ...) printk(KERN_WARN "keymash: " msg, ##__VA_ARGS__)
+#define keymash_err(msg, ...) printk(KERN_ERR "keymash: " msg, ##__VA_ARGS__)
+
+static dev_t keymash_dev = MKDEV(0, 0);
+static struct cdev keymash_cdev;
+static struct class *keymash_class;
+static struct device *keymash_device;
+
+#define KEYMASH_MINOR_COUNT 1
+#define KEYMASH_DEVICE_NAME "keymash"
+
+static const char keymash_chrs[] = "asdfghjkl;";
+#define KEYMASH_CHRS_LEN (ARRAY_SIZE(keymash_chrs) - 1) /* minus NUL */
+
+static void keymash_gay(void *buf, size_t len)
+{
+	unsigned char *cbuf = buf;
+
+	get_random_bytes(buf, len);
+
+	while (len--) {
+		unsigned char rnd = *cbuf;
+		*cbuf++ = keymash_chrs[rnd % KEYMASH_CHRS_LEN];
+	}
+}
+
+static ssize_t keymash_read(struct file *file, char __user *user_buffer,
+			    size_t size, loff_t *offset)
+{
+	ssize_t ret;
+	void *gay = kmalloc(size, GFP_KERNEL);
+
+	if (gay) {
+		keymash_gay(gay, size);
+		if (copy_to_user(user_buffer, gay, size))
+			ret = -EFAULT;
+		else
+			ret = size;
+		kfree(gay);
+	} else {
+		ret = -ENOMEM;
+	}
+
+	return ret;
+}
+
+static const struct file_operations keymash_fops = {
+	.owner = THIS_MODULE,
+	.read = keymash_read,
+};
+
+static char *keymash_devnode(struct device *dev, umode_t *mode)
+{
+	if (mode)
+		*mode = 0444;
+	return NULL;
+}
+
+__init
+static int keymash_init(void)
+{
+	int err = -1;
+
+	err = alloc_chrdev_region(&keymash_dev, 0, KEYMASH_MINOR_COUNT, KEYMASH_DEVICE_NAME);
+	if (err < 0) {
+		keymash_err("alloc_chrdev_region() returned %d\n", err);
+		goto err_alloc_chrdev_region;
+	}
+	keymash_debug("using device major number %d\n", MAJOR(keymash_dev));
+
+	cdev_init(&keymash_cdev, &keymash_fops);
+	err = cdev_add(&keymash_cdev, keymash_dev, 1);
+	if (err < 0) {
+		keymash_err("cdev_init() returned %d\n", err);
+		goto err_cdev_add;
+	}
+
+	keymash_class = class_create(THIS_MODULE, "kmsh");
+	if (IS_ERR(keymash_class)) {
+		err = PTR_ERR(keymash_class);
+		keymash_err("class_create() returned %d\n", err);
+		goto err_class_create;
+	}
+	keymash_class->devnode = keymash_devnode;
+
+	keymash_device = device_create(keymash_class, NULL, keymash_dev, NULL, KEYMASH_DEVICE_NAME);
+	if (IS_ERR(keymash_device)) {
+		err = PTR_ERR(keymash_device);
+		keymash_err("device_create() returned %d\n", err);
+		goto err_device_create;
+	}
+
+	return 0;
+
+err_device_create:
+	class_unregister(keymash_class);
+	class_destroy(keymash_class);
+err_class_create:
+	cdev_del(&keymash_cdev);
+err_cdev_add:
+	unregister_chrdev_region(keymash_dev, KEYMASH_MINOR_COUNT);
+err_alloc_chrdev_region:
+	return err;
+}
+module_init(keymash_init);
+
+__exit
+static void keymash_exit(void)
+{
+	device_destroy(keymash_class, keymash_dev);
+	class_unregister(keymash_class);
+	class_destroy(keymash_class);
+	cdev_del(&keymash_cdev);
+	unregister_chrdev_region(keymash_dev, KEYMASH_MINOR_COUNT);
+	keymash_info("sayounara sekai UwU\n");
+}
+module_exit(keymash_exit);