Merge c and rust modules

03_character_device/Makefile

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+obj-m += test_module.o
+
+all:
+	make -C $(LINUX_MODULES_FOLDER)/build M=$(PWD) modules
+
+clean:
+	make -C $(LINUX_MODULES_FOLDER)/build M=$(PWD) clean

03_character_device/README.md

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+## Additionnal informations
+
+To test character device, your need create the device.
+
+Step 1: Get major number of your module device
+
+```bash
+cat /proc/devices | grep flodev
+```
+
+Step 2: Create device (as root)
+
+```bash
+mknod /dev/[wanted name] -c <major_number> 0
+```
+
+Exemple (as root):
+
+```bash
+cat /proc/devices | grep flodev # => 236 flodev
+mknod /dev/flodev0 c 236 0
+echo "Salut" >> /dev/flodev0
+dmesg | tail # =>
+#   flodev - Ouverture du périphérique
+#   flodev - Message reçu: Salut
+#   flodev - Fermeture du périphérique
+rm /dev/flodev0
+```
+
+
+

03_character_device/test_module.c

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+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+
+#define DEVICE_NAME "flodev"
+#define CLASS_NAME "chardrv"
+
+static int major_number;
+static char msg[256] = { 0 };
+static short size_of_msg;
+static int device_open(struct inode *, struct file *);
+static int device_release(struct inode *, struct file *);
+static ssize_t device_read(struct file *, char *, size_t, loff_t *);
+static ssize_t device_write(struct file *, const char *, size_t, loff_t *);
+
+static struct file_operations fops = {
+	.read = device_read,
+	.write = device_write,
+	.open = device_open,
+	.release = device_release,
+};
+
+static int __init basic_module_init(void)
+{
+	pr_info("Bonjour! Le module est chargé.\n");
+	major_number = register_chrdev(0, DEVICE_NAME, &fops);
+	if (major_number < 0) {
+		pr_info("Erreur lors de l'enregistrement du périphérique de caractère\n");
+		return major_number;
+	}
+	pr_info("Périphérique de caractère enregistré avec le numéro de majeur %d\n",
+		major_number);
+	return 0;
+}
+
+static void __exit basic_module_exit(void)
+{
+	unregister_chrdev(major_number, DEVICE_NAME);
+	pr_info("Au revoir! Le module est déchargé.\n");
+}
+
+static int device_open(struct inode *inode, struct file *file)
+{
+	pr_info("flodev - Ouverture du périphérique\n");
+	return 0;
+}
+
+static int device_release(struct inode *inode, struct file *file)
+{
+	pr_info("flodev - Fermeture du périphérique\n");
+	return 0;
+}
+
+static ssize_t device_read(struct file *filp, char *buffer, size_t length,
+			   loff_t *offset)
+{
+	int bytes_read = 0;
+	if (*offset >= size_of_msg) {
+		return 0;
+	}
+	if (*offset + length > size_of_msg) {
+		length = size_of_msg - *offset;
+	}
+	if (copy_to_user(buffer, msg + *offset, length)) {
+		return -EFAULT;
+	}
+	*offset += length;
+	bytes_read = length;
+	pr_info("flodev - Lecture de %d bytes\n", bytes_read);
+	return bytes_read;
+}
+
+static ssize_t device_write(struct file *filp, const char *buff, size_t len,
+			    loff_t *off)
+{
+	if (copy_from_user(msg, buff, len)) {
+		return -EFAULT;
+	}
+	size_of_msg = len;
+	pr_info("flodev - Message reçu: %s\n", msg);
+	return len;
+}
+
+module_init(basic_module_init);
+module_exit(basic_module_exit);
+
+MODULE_LICENSE("MIT License");
+MODULE_AUTHOR("Florian RICHER <florian.richer@protonmail.com>");
+MODULE_DESCRIPTION("Un module noyau avec un périphérique de caractère");
+MODULE_VERSION("1.0");