add assignement 00 to 08

05/rw.c

@@ -0,0 +1,35 @@
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/uaccess.h>
+
+#define VALUE "tomoron"
+
+ssize_t dev_read(struct file *f, char __user *buf, size_t len, loff_t *off);
+ssize_t dev_write(struct file *f, const char __user *buf, size_t len, loff_t *off);
+
+ssize_t dev_read(struct file *f, char __user *buf, size_t len, loff_t *off) {
+    char msg[] = VALUE;
+	pr_info("someone read from the file\n");
+    return simple_read_from_buffer(buf, len, off, msg, sizeof(msg) - 1);
+}
+
+
+ssize_t dev_write(struct file *f, const char __user *buf, size_t len, loff_t *off) {
+    char kbuf[64];
+    if (len > sizeof(kbuf) - 1)
+        return -EINVAL;
+    if (copy_from_user(kbuf, buf, len))
+        return -EINVAL;
+
+    kbuf[len] = '\0';
+
+    if (strcmp(kbuf, VALUE) == 0)
+	{
+		pr_info("someone wrote the right string\n");
+        return len;
+	}
+	pr_info("someone wrote the wrong string\n");
+    return -EINVAL;
+}