add character device to the system

2 files changed, 37 insertions, 6 deletions

diff --git a/1/config.h b/1/config.h
new file mode 100644
index 0000000..1d15f75
--- /dev/null
+++ b/1/config.h
@@ -0,0 +1,5 @@
+#pragma once
+
+#define NODE_MAJOR 500
+#define NODE_MINOR 0
+
diff --git a/1/main.c b/1/main.c
index 88ae0d0..66ceac4 100644
--- a/1/main.c
+++ b/1/main.c
@@ -1,26 +1,52 @@
+#include <linux/cdev.h>
 #include <linux/init.h>
 #include <linux/module.h>
 
 #include "fopdrv.h"
+#include "config.h"
 
-MODULE_LICENSE("MIT");
-
+struct cdev *cdev;
 struct file_operations fops = {
-  .read = fop_read,
-  .write = fop_write,
-  .open = fop_open,
-  .release = fop_release,
+	.read = fop_read,
+	.write = fop_write,
+	.open = fop_open,
+	.release = fop_release,
 };
 
 static int mod_init(void) {
+	int err;
+	cdev = cdev_alloc();
+	dev_t node = MKDEV(NODE_MAJOR, NODE_MINOR);
+
+	if (!cdev) {
+		err = ENOMEM;
+		goto free_cdev;
+	}
+
+	cdev->ops = &fops;
+
+	err = cdev_add(cdev, node, 1);
+	if (err < 0) {
+		printk(KERN_ERR "cdev_add failed w/ error code %d\n", err);
+		goto free_cdev;
+	}
+
 	printk("%s\n", __PRETTY_FUNCTION__);
 	return 0;
+
+free_cdev:
+	cdev_del(cdev);
+
+	printk("%s: %d\n", __PRETTY_FUNCTION__, err);
+	return err;
 }
 
 static void mod_exit(void) {
+	cdev_del(cdev);
 	printk("%s\n", __PRETTY_FUNCTION__);
 }
 
 module_init(mod_init);
 module_exit(mod_exit);
+MODULE_LICENSE("MIT");