From 47bdfecedb09a7f2384820e94d2b443a20c3696e Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Wed, 19 Oct 2022 21:11:12 +0200
Subject: [PATCH] Devices: Add /dev/uptime

This file contains how many milliseconds have passed since boot at the time of reading it :)
---
 kernel/include/fs/devices/Uptime.h |  9 +++++++++
 kernel/src/fs/devices/DeviceFS.cpp |  2 ++
 kernel/src/fs/devices/Uptime.cpp   | 24 ++++++++++++++++++++++++
 3 files changed, 35 insertions(+)
 create mode 100644 kernel/include/fs/devices/Uptime.h
 create mode 100644 kernel/src/fs/devices/Uptime.cpp

diff --git a/kernel/include/fs/devices/Uptime.h b/kernel/include/fs/devices/Uptime.h
new file mode 100644
index 00000000..98e7baa9
--- /dev/null
+++ b/kernel/include/fs/devices/Uptime.h
@@ -0,0 +1,9 @@
+#pragma once
+#include "fs/VFS.h"
+
+namespace UptimeDevice
+{
+    VFS::Node* create_new(const char* devname);
+
+    ssize_t read(VFS::Node* node, size_t offset, size_t size, 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 edb9a72a..80eb45fa 100644
--- a/kernel/src/fs/devices/DeviceFS.cpp
+++ b/kernel/src/fs/devices/DeviceFS.cpp
@@ -3,6 +3,7 @@
 #include "fs/devices/Keyboard.h"
 #include "fs/devices/Random.h"
 #include "fs/devices/Serial.h"
+#include "fs/devices/Uptime.h"
 #include "fs/devices/Version.h"
 #include "std/stdlib.h"
 #include "std/string.h"
@@ -29,6 +30,7 @@ VFS::Node* DeviceFS::get()
     devfs_files[devfs_file_count++] = SerialDevice::create_new("serial");
     devfs_files[devfs_file_count++] = RandomDevice::create_new("random");
     devfs_files[devfs_file_count++] = KeyboardDevice::create_new("kbd");
+    devfs_files[devfs_file_count++] = UptimeDevice::create_new("uptime");
     return devfs_root;
 }
 
diff --git a/kernel/src/fs/devices/Uptime.cpp b/kernel/src/fs/devices/Uptime.cpp
new file mode 100644
index 00000000..a80cd09d
--- /dev/null
+++ b/kernel/src/fs/devices/Uptime.cpp
@@ -0,0 +1,24 @@
+#include "fs/devices/Uptime.h"
+#include "std/stdio.h"
+#include "std/stdlib.h"
+#include "std/string.h"
+#include "thread/PIT.h"
+
+VFS::Node* UptimeDevice::create_new(const char* devname)
+{
+    VFS::Node* dev = new VFS::Node;
+    dev->read_func = UptimeDevice::read;
+    dev->inode = 0;
+    dev->length = 0;
+    dev->type = VFS_DEVICE;
+    dev->flags = 0;
+    strncpy(dev->name, devname, sizeof(dev->name));
+    return dev;
+}
+
+ssize_t UptimeDevice::read(VFS::Node* node, size_t, size_t size, char* buffer)
+{
+    if (!node) return -1;
+    snprintf(buffer, size + 1, "%ld", PIT::ms_since_boot); // FIXME: Support offseting this read
+    return (ssize_t)size;
+}
\ No newline at end of file