Kernel: Add /dev/null

kernel/include/fs/devices/NullDevice.h

@@ -0,0 +1,10 @@
+#pragma once
+#include "fs/VFS.h"
+
+namespace NullDevice
+{
+    VFS::Node* create_new(const char* devname);
+
+    ssize_t write(VFS::Node* node, size_t offset, size_t size, const char* buffer);
+    ssize_t read(VFS::Node* node, size_t offset, size_t size, char* buffer);
+}

kernel/src/fs/devices/DeviceFS.cpp

@@ -1,6 +1,7 @@
 #include "fs/devices/DeviceFS.h"
 #include "fs/devices/Console.h"
 #include "fs/devices/Keyboard.h"
+#include "fs/devices/NullDevice.h"
 #include "fs/devices/Random.h"
 #include "fs/devices/Serial.h"
 #include "fs/devices/Uptime.h"
@@ -32,6 +33,7 @@ VFS::Node* DeviceFS::get()
     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");
+    devfs_files[devfs_file_count++] = NullDevice::create_new("null");
     devfs_root->length = devfs_file_count;
     return devfs_root;
 }

kernel/src/fs/devices/NullDevice.cpp

@@ -0,0 +1,29 @@
+#include "fs/devices/NullDevice.h"
+#include "std/stdio.h"
+#include "std/stdlib.h"
+#include "std/string.h"
+
+VFS::Node* NullDevice::create_new(const char* devname)
+{
+    VFS::Node* dev = new VFS::Node;
+    dev->write_func = NullDevice::write;
+    dev->read_func = NullDevice::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 NullDevice::write(VFS::Node* node, size_t, size_t size, const char*)
+{
+    if (!node) return -1;
+    return (ssize_t)size;
+}
+
+ssize_t NullDevice::read(VFS::Node* node, size_t, size_t, char*)
+{
+    if (!node) return -1;
+    return 0;
+}