From eb03ae91e0a79f13dcea5f7afcd3608d87b381fc Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Wed, 12 Oct 2022 10:44:30 +0200
Subject: [PATCH] Devices: Add a new Serial device

This device permits userspace to interface with the serial port.
---
 apps/src/init.c                    | 17 +++++++++++++++++
 kernel/include/fs/devices/Serial.h |  9 +++++++++
 kernel/src/fs/devices/DeviceFS.cpp |  2 ++
 kernel/src/fs/devices/Serial.cpp   | 25 +++++++++++++++++++++++++
 4 files changed, 53 insertions(+)
 create mode 100644 kernel/include/fs/devices/Serial.h
 create mode 100644 kernel/src/fs/devices/Serial.cpp

diff --git a/apps/src/init.c b/apps/src/init.c
index 007547da..732110a1 100644
--- a/apps/src/init.c
+++ b/apps/src/init.c
@@ -47,6 +47,23 @@ int main()
         return 1;
     }
 
+    FILE* serial = fopen("/dev/serial", "r");
+    if (!serial)
+    {
+        perror("fopen");
+        return 1;
+    }
+    if (fputs("Hello from init!\n", serial) < 0)
+    {
+        perror("fputs");
+        return 1;
+    }
+    if (fclose(serial) < 0)
+    {
+        perror("fclose");
+        return 1;
+    }
+
     printf("Welcome to Luna!\n");
 
     printf("Running as tid %ld\n\n", gettid());
diff --git a/kernel/include/fs/devices/Serial.h b/kernel/include/fs/devices/Serial.h
new file mode 100644
index 00000000..79963e61
--- /dev/null
+++ b/kernel/include/fs/devices/Serial.h
@@ -0,0 +1,9 @@
+#pragma once
+#include "fs/VFS.h"
+
+namespace SerialDevice
+{
+    VFS::Node* create_new();
+
+    ssize_t write(VFS::Node* node, size_t offset, size_t size, const char* buffer);
+}
\ No newline at end of file
diff --git a/kernel/src/fs/devices/DeviceFS.cpp b/kernel/src/fs/devices/DeviceFS.cpp
index 4bc698a4..e0fe053b 100644
--- a/kernel/src/fs/devices/DeviceFS.cpp
+++ b/kernel/src/fs/devices/DeviceFS.cpp
@@ -1,5 +1,6 @@
 #include "fs/devices/DeviceFS.h"
 #include "fs/devices/Console.h"
+#include "fs/devices/Serial.h"
 #include "fs/devices/Version.h"
 #include "std/stdlib.h"
 #include "std/string.h"
@@ -23,6 +24,7 @@ VFS::Node* DeviceFS::get()
 
     devfs_files[devfs_file_count++] = VersionDevice::create_new();
     devfs_files[devfs_file_count++] = ConsoleDevice::create_new();
+    devfs_files[devfs_file_count++] = SerialDevice::create_new();
     return devfs_root;
 }
 
diff --git a/kernel/src/fs/devices/Serial.cpp b/kernel/src/fs/devices/Serial.cpp
new file mode 100644
index 00000000..b3b5f729
--- /dev/null
+++ b/kernel/src/fs/devices/Serial.cpp
@@ -0,0 +1,25 @@
+#include "io/Serial.h"
+#include "config.h"
+#include "fs/devices/Serial.h"
+#include "std/stdio.h"
+#include "std/stdlib.h"
+#include "std/string.h"
+
+VFS::Node* SerialDevice::create_new()
+{
+    VFS::Node* dev = new VFS::Node;
+    dev->write_func = SerialDevice::write;
+    dev->inode = 0;
+    dev->length = 0;
+    dev->type = VFS_FILE;
+    dev->flags = 0;
+    strncpy(dev->name, "serial", sizeof(dev->name));
+    return dev;
+}
+
+ssize_t SerialDevice::write(VFS::Node* node, size_t, size_t size, const char* buffer)
+{
+    if (!node) return -1;
+    Serial::write(buffer, size);
+    return (ssize_t)size;
+}
\ No newline at end of file