Hw

test.c

@@ -1,67 +1,192 @@
 #include <linux/cdev.h>
 #include <linux/fs.h>
-#include <linux/init.h>
 #include <linux/kdev_t.h>
-#include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/printk.h>
+#include <asm/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/mutex.h>
 
 MODULE_DESCRIPTION("My kernel module");
-MODULE_AUTHOR("Me");
+MODULE_AUTHOR("maxsos");
 MODULE_LICENSE("GPL");
 
 #define DUMMY_MINOR 0
 #define DUMMY_NUM_MINORS 1
 #define DUMMY_MODULE_NAME "dummy"
 
+DEFINE_MUTEX(my_mutex);
+
+struct node {
+	struct node* next;
+    size_t len;
+    char* line;
+};
+
 struct dummy_device_data {
 	struct cdev cdev;
+	bool is_read;
 	dev_t dev;
+	struct node* node;
 };
 
 static struct dummy_device_data dummy_device_data[DUMMY_NUM_MINORS];
+static int dummy_check_if_opened_before[100];
 
-static int dummy_open(struct inode *inode, struct file *file)
-{
+static int dummy_open(struct inode *inode, struct file *file) {
 	printk("%s: opened.\n", DUMMY_MODULE_NAME);
-
 	return 0;
 }
 
-static int dummy_release (struct inode *inode, struct file *file)
-{
+static int dummy_release(struct inode *inode, struct file *file) {
 	printk("%s: closed.\n", DUMMY_MODULE_NAME);
-
 	return 0;
 }
 
+static ssize_t dummy_read(struct file *file, char __user *user_buffer,
+			  size_t size, loff_t * offset) {
+	mutex_lock(&my_mutex);
+	ssize_t error = 0;
+	int i;
+	for(i = 0; i < 100; ++i) 
+		if (dummy_check_if_opened_before[i] == current->pid) {
+			dummy_check_if_opened_before[i] = 0;
+			goto read_out_err;
+		}
+
+    struct dummy_device_data *ddd = &dummy_device_data[0];
+	struct node *n = ddd->node;	
+
+	if(dummy_device_data[0].is_read) {
+		dummy_device_data[0].is_read = false;
+		goto read_out_err;
+	}
+
+	if(n == NULL) {
+		printk("NODE IS NULL:((\n");
+		goto read_out_err;
+	}
+    struct node *next = n->next;
+
+	if(!n->line || !n->len) {
+		printk("LINE IS NULL:((\n");
+		goto read_out_err;
+	}
+
+	printk("READ %zu//%zu \n", size, dummy_device_data[0].node->len);
+	size_t len = n->len;
+
+    if (copy_to_user(user_buffer, n->line, len)) {
+		error = -EFAULT;
+		goto read_out_err;
+	}
+
+    vfree(n->line);
+	vfree(n);
+    dummy_device_data[0].node = next;
+	dummy_device_data[0].is_read = true;
+	mutex_unlock(&my_mutex);
+
+	for(i = 0; i < 100; ++i)
+		if (dummy_check_if_opened_before[i] != 0) {
+			dummy_check_if_opened_before[i] = current->pid;
+			break;
+		}
+
+	return len;
+
+read_out_err:
+	mutex_unlock(&my_mutex);
+	return error;
+}
+
+static ssize_t dummy_write(struct file *file, const char __user *user_buffer,
+			   size_t size, loff_t * offset) {
+	mutex_lock(&my_mutex);
+	ssize_t error = 0;
+	// printk("Write\n");
+ 	struct dummy_device_data *ddd = &dummy_device_data[0];
+	struct node *n = ddd->node;
+
+    if (size <= 0)
+        return 0;
+
+	if (!n) {
+		ddd->node = vmalloc(sizeof(struct node));
+		n = ddd->node;
+	} else {
+		while (n->next) 
+			n = n->next;
+		n->next = vmalloc(sizeof(struct node));
+		n = n->next;
+	}
+
+	if (!n) {
+		pr_err("%s: vmalloc failed: can't alloc memory for node. \n",
+				__FUNCTION__, size); 
+        error = -ENOMEM;
+		goto write_out_err;
+	}
+
+	n->line = vmalloc(size * sizeof(char));
+
+    if (!n->line) {
+		pr_err("%s: vmalloc failed: can't alloc memory for line %zu size. \n",
+				__FUNCTION__, size); 
+		error = -ENOMEM;
+		goto write_out_err;
+    }
+
+    if (copy_from_user(n->line, user_buffer, size)) {
+		error = -EFAULT;
+		goto write_out_err;
+	}
+
+    n->len = size;
+	n->next = NULL;
+	// printk("Address: %p\t%p\n", dummy_device_data[0].node, n);
+	printk("WRITEN: line=%s, len=%zu, size=%zu\n", 
+				n->line, n->len, size);
+
+	mutex_unlock(&my_mutex);
+	return size;
+
+write_out_err:
+	mutex_unlock(&my_mutex);
+	return error;
+}
+
 static struct file_operations dummy_fops = {
 	.owner = THIS_MODULE,
-	.open = dummy_open,
-	.release = dummy_release
+	.open = dummy_open, 
+	.release = dummy_release,
+	.read = dummy_read,
+	.write = dummy_write,
 };
 
 static int dummy_chrdev_init(void)
 {
 	int error;
 	dev_t first_dev;
-	unsigned int major, first_minor;
 	int i;
 
-	error = alloc_chrdev_region(&first_dev, DUMMY_MINOR, DUMMY_NUM_MINORS,
-				    DUMMY_MODULE_NAME);
+	error = alloc_chrdev_region(&first_dev, DUMMY_MINOR,
+			DUMMY_NUM_MINORS, DUMMY_MODULE_NAME);
+
 	if (error) {
-		pr_err("%s: alloc_chrdev_region failed: %d\n",
-		       __FUNCTION__, error);
+		pr_err("%s: alloc_chrdev_region failed: %d. \n",
+				__FUNCTION__, error);
 		return error;
 	}
-
-	major = MAJOR(first_dev);
-	first_minor = MINOR(first_dev);
-	BUG_ON(first_minor + DUMMY_NUM_MINORS > MINORMASK);
-
-	for (i = 0; i < DUMMY_NUM_MINORS; i++) {
-		dummy_device_data[i].dev = MKDEV(major, first_minor + i);
+	BUG_ON(MINOR(first_dev) + DUMMY_NUM_MINORS > MINORMASK);
+
+	for(i = 0; i < DUMMY_NUM_MINORS; ++i) {
+		dummy_device_data[i].dev = MKDEV(MAJOR(first_dev), 
+						 MINOR(first_dev) + i);	
+		dummy_device_data[i].node = NULL;
+        // dummy_device_data[i].node = vmalloc(sizeof(struct node));
+		// dummy_device_data[i].node->line = NULL;
+		// dummy_device_data[i].node->next = NULL;
+		// dummy_device_data[i].node->len = 0;
 	}
 
 	return 0;
@@ -70,19 +195,16 @@ static int dummy_chrdev_init(void)
 static int dummy_cdev_init(struct dummy_device_data *device_data)
 {
 	int error;
-	struct cdev *cdev = &device_data->cdev;
 
-	cdev_init(cdev, &dummy_fops);
-	error = cdev_add(cdev, device_data->dev, 1);
+	cdev_init(&device_data->cdev, &dummy_fops);
+	error = cdev_add(&device_data->cdev, device_data->dev, 1);
+
 	if (error) {
-		pr_err("%s: cdev_add failed: %d\n",
-		       __FUNCTION__, error);
+		pr_err("%s: alloc_cdev_add failed: %d. \n",
+				__FUNCTION__, error);
+		return error;
 	}
-
-	printk("%s: created character device %x:%x (ma:mi).\n", DUMMY_MODULE_NAME,
-	       MAJOR(device_data->dev), MINOR(device_data->dev));
-
-	return error;
+	return 0;
 }
 
 static int dummy_init(void)
@@ -106,14 +228,38 @@ static int dummy_init(void)
 	if (error) {
 		pr_err("%s: dummy_cdev_init failed: %d\n",
 			 __FUNCTION__, error);
+		return error;
 	}
+	mutex_init(&my_mutex);
+	for(i = 0; i < 100; ++i)
+		dummy_check_if_opened_before[i] = 0;
 
-        return 0;
+    return 0;
 }
 
 static void dummy_exit(void)
 {
-        printk("%s: Bye\n", __FUNCTION__);
+	int i;
+	for(i = 0; i < DUMMY_NUM_MINORS; ++i) {
+		struct dummy_device_data *ddd = &dummy_device_data[0];
+		struct node *n = ddd->node;
+		struct node *temp;
+
+		while (n) {
+			vfree(n->line);
+			temp = n->next;
+			vfree(n);
+			n = temp;
+		} 
+		cdev_del(&dummy_device_data[i].cdev);
+	}
+
+	unregister_chrdev_region(dummy_device_data[0].dev,
+				 DUMMY_NUM_MINORS);
+
+	mutex_destroy(&my_mutex);
+
+	printk("%s: Bye\n", __FUNCTION__);
 }
 
 module_init(dummy_init);