Kernel: Make pseudo terminals not overwrite old data

If pseudo terminal buffer was filled, old implementation would overwrite
old data. This is bad if producer is capable of producing more data than
consumer can handle.

BAN/include/BAN/Array.h

@@ -18,78 +18,78 @@ namespace BAN
 		using const_iterator = ConstIteratorSimple<T, Array>;
 
 	public:
-		Array() = default;
-		Array(const T&);
+		constexpr Array() = default;
+		constexpr Array(const T&);
 
 		iterator begin() { return iterator(m_data); }
 		iterator end() { return iterator(m_data + size()); }
 		const_iterator begin() const { return const_iterator(m_data); }
 		const_iterator end() const { return const_iterator(m_data + size()); }
 
-		const T& operator[](size_type) const;
-		T& operator[](size_type);
+		constexpr const T& operator[](size_type) const;
+		constexpr T& operator[](size_type);
 
-		const T& back() const;
-		T& back();
-		const T& front() const;
-		T& front();
+		constexpr const T& back() const;
+		constexpr T& back();
+		constexpr const T& front() const;
+		constexpr T& front();
 
 		Span<T> span() { return Span(m_data, size()); }
 		const Span<T> span() const { return Span(m_data, size()); }
 
 		constexpr size_type size() const;
 
-		const T* data() const { return m_data; }
-		T* data() { return m_data; }
+		constexpr const T* data() const { return m_data; }
+		constexpr T* data() { return m_data; }
 
 	private:
 		T m_data[S] {};
 	};
 
 	template<typename T, size_t S>
-	Array<T, S>::Array(const T& value)
+	constexpr Array<T, S>::Array(const T& value)
 	{
 		for (size_type i = 0; i < S; i++)
 			m_data[i] = value;
 	}
 
 	template<typename T, size_t S>
-	const T& Array<T, S>::operator[](size_type index) const
+	constexpr const T& Array<T, S>::operator[](size_type index) const
 	{
 		ASSERT(index < S);
 		return m_data[index];
 	}
 
 	template<typename T, size_t S>
-	T& Array<T, S>::operator[](size_type index)
+	constexpr T& Array<T, S>::operator[](size_type index)
 	{
 		ASSERT(index < S);
 		return m_data[index];
 	}
 
 	template<typename T, size_t S>
-	const T& Array<T, S>::back() const
+	constexpr const T& Array<T, S>::back() const
 	{
 		ASSERT(S != 0);
 		return m_data[S - 1];
 	}
 
 	template<typename T, size_t S>
-	T& Array<T, S>::back()
+	constexpr T& Array<T, S>::back()
 	{
 		ASSERT(S != 0);
 		return m_data[S - 1];
 	}
 
 	template<typename T, size_t S>
-	const T& Array<T, S>::front() const
+	constexpr const T& Array<T, S>::front() const
 	{
 		ASSERT(S != 0);
 		return m_data[0];
 	}
 
 	template<typename T, size_t S>
-	T& Array<T, S>::front()
+	constexpr T& Array<T, S>::front()
 	{
 		ASSERT(S != 0);
 		return m_data[0];

kernel/include/kernel/Terminal/FramebufferTerminal.h

@@ -27,9 +27,10 @@ namespace Kernel
 		const LibFont::Font& font() const override { return m_font; };
 
 	private:
-		FramebufferTerminalDriver(BAN::RefPtr<FramebufferDevice> framebuffer_device)
-			: m_framebuffer_device(framebuffer_device)
-		{ }
+		FramebufferTerminalDriver(BAN::RefPtr<FramebufferDevice> framebuffer_device, const Palette& palette)
+			: TerminalDriver(palette)
+			, m_framebuffer_device(framebuffer_device)
+		{}
 
 		void read_cursor();
 		void show_cursor(bool use_data);
@@ -42,7 +43,7 @@ namespace Kernel
 		uint32_t m_cursor_y { 0 };
 		bool m_cursor_shown { true };
 		BAN::Vector<uint32_t> m_cursor_data;
-		static constexpr Color m_cursor_color = TerminalColor::BRIGHT_WHITE;
+		static constexpr Color m_cursor_color = TerminalColor::WHITE;
 	};
 
 }

kernel/include/kernel/Terminal/PseudoTerminal.h

@@ -20,7 +20,7 @@ namespace Kernel
 
 		BAN::ErrorOr<BAN::String> ptsname();
 
-		void putchar(uint8_t ch);
+		bool putchar(uint8_t ch);
 
 	protected:
 		BAN::ErrorOr<size_t> read_impl(off_t, BAN::ByteSpan) override;
@@ -61,7 +61,7 @@ namespace Kernel
 		void clear() override;
 
 	protected:
-		void putchar_impl(uint8_t ch) override;
+		bool putchar_impl(uint8_t ch) override;
 
 		BAN::ErrorOr<long> ioctl_impl(int, void*) override;
 

kernel/include/kernel/Terminal/Serial.h

@@ -53,7 +53,7 @@ namespace Kernel
 
 	protected:
 		virtual BAN::StringView name() const override { return m_name; }
-		virtual void putchar_impl(uint8_t) override;
+		virtual bool putchar_impl(uint8_t) override;
 
 	private:
 		SerialTTY(Serial);

kernel/include/kernel/Terminal/TTY.h

@@ -58,14 +58,14 @@ namespace Kernel
 	protected:
 		TTY(mode_t mode, uid_t uid, gid_t gid);
 
-		virtual void putchar_impl(uint8_t ch) = 0;
+		virtual bool putchar_impl(uint8_t ch) = 0;
 		virtual void update_cursor() {}
 
 		virtual BAN::ErrorOr<size_t> read_impl(off_t, BAN::ByteSpan) override;
 		virtual BAN::ErrorOr<size_t> write_impl(off_t, BAN::ConstByteSpan) override;
 
 	private:
-		void putchar(uint8_t ch);
+		bool putchar(uint8_t ch);
 		void do_backspace();
 
 	protected:

kernel/include/kernel/Terminal/TerminalDriver.h

@@ -12,20 +12,28 @@ namespace Kernel
 	public:
 		struct Color
 		{
+			constexpr Color()
+				: rgb(0)
+			{ }
 			constexpr Color(uint32_t rgb)
 				: rgb(rgb)
 			{ }
 			constexpr Color(uint8_t r, uint8_t g, uint8_t b)
 				: rgb(((uint32_t)r << 16) | ((uint32_t)g << 8) | b)
 			{ }
-			uint8_t red()	const { return (rgb >> 0x10) & 0xFF; }
-			uint8_t green() const { return (rgb >> 0x08) & 0xFF; }
-			uint8_t blue()	const { return (rgb >> 0x00) & 0xFF; }
+			constexpr uint8_t red() const { return (rgb >> 0x10) & 0xFF; }
+			constexpr uint8_t green() const { return (rgb >> 0x08) & 0xFF; }
+			constexpr uint8_t blue() const { return (rgb >> 0x00) & 0xFF; }
 			uint32_t rgb;
 		};
 
+		using Palette = BAN::Array<Color, 16>;
+
 	public:
 		static BAN::ErrorOr<void> initialize_from_boot_info();
+		TerminalDriver(const Palette& palette)
+			: m_palette(palette)
+		{}
 		virtual ~TerminalDriver() {}
 		virtual uint32_t width() const = 0;
 		virtual uint32_t height() const = 0;
@@ -40,29 +48,19 @@ namespace Kernel
 		virtual bool has_font() const { return false; }
 		virtual BAN::ErrorOr<void> set_font(LibFont::Font&&) { return BAN::Error::from_errno(EINVAL); }
 		virtual const LibFont::Font& font() const { ASSERT_NOT_REACHED(); }
+
+		const Palette& palette() const { return m_palette; }
+
+	protected:
+		Palette m_palette;
 	};
 
 	extern BAN::RefPtr<TerminalDriver> g_terminal_driver;
 
 	namespace TerminalColor
 	{
-		static constexpr TerminalDriver::Color BLACK			= 0x000000;
-		static constexpr TerminalDriver::Color RED				= 0xFF0000;
-		static constexpr TerminalDriver::Color GREEN			= 0x00FF00;
-		static constexpr TerminalDriver::Color YELLOW			= 0xFFFF00;
-		static constexpr TerminalDriver::Color BLUE				= 0x0000FF;
-		static constexpr TerminalDriver::Color MAGENTA			= 0xFF00FF;
-		static constexpr TerminalDriver::Color CYAN				= 0x00FFFF;
-		static constexpr TerminalDriver::Color WHITE			= 0xBFBFBF;
-
-		static constexpr TerminalDriver::Color BRIGHT_BLACK		= 0x3F3F3F;
-		static constexpr TerminalDriver::Color BRIGHT_RED		= 0xFF7F7F;
-		static constexpr TerminalDriver::Color BRIGHT_GREEN		= 0x7FFF7F;
-		static constexpr TerminalDriver::Color BRIGHT_YELLOW	= 0xFFFF7F;
-		static constexpr TerminalDriver::Color BRIGHT_BLUE		= 0x7F7FFF;
-		static constexpr TerminalDriver::Color BRIGHT_MAGENTA	= 0xFF7FFF;
-		static constexpr TerminalDriver::Color BRIGHT_CYAN		= 0x7FFFFF;
-		static constexpr TerminalDriver::Color BRIGHT_WHITE		= 0xFFFFFF;
+		constexpr TerminalDriver::Color BLACK = 0x000000;
+		constexpr TerminalDriver::Color WHITE = 0xFFFFFF;
 	}
 
 }

kernel/include/kernel/Terminal/TextModeTerminal.h

@@ -21,8 +21,9 @@ namespace Kernel
 		void set_cursor_position(uint32_t, uint32_t) override;
 
 	private:
-		TextModeTerminalDriver(paddr_t paddr, uint32_t width, uint32_t height, uint32_t pitch)
-			: m_paddr(paddr)
+		TextModeTerminalDriver(paddr_t paddr, uint32_t width, uint32_t height, uint32_t pitch, const Palette& palette)
+			: TerminalDriver(palette)
+			, m_paddr(paddr)
 			, m_width(width)
 			, m_height(height)
 			, m_pitch(pitch)
@@ -36,7 +37,7 @@ namespace Kernel
 		const uint32_t m_height;
 		const uint32_t m_pitch;
 		vaddr_t m_vaddr { 0 };
-		static constexpr Color s_cursor_color = TerminalColor::BRIGHT_WHITE;
+		static constexpr Color s_cursor_color = TerminalColor::WHITE;
 	};
 
 }

kernel/include/kernel/Terminal/VirtualTTY.h

@@ -11,6 +11,9 @@ namespace Kernel
 
 	class VirtualTTY : public TTY
 	{
+	public:
+		using Palette = TerminalDriver::Palette;
+
 	public:
 		static BAN::ErrorOr<BAN::RefPtr<VirtualTTY>> create(BAN::RefPtr<TerminalDriver>);
 
@@ -23,7 +26,7 @@ namespace Kernel
 
 	protected:
 		virtual BAN::StringView name() const override { return m_name; }
-		virtual void putchar_impl(uint8_t ch) override;
+		virtual bool putchar_impl(uint8_t ch) override;
 		void update_cursor() override;
 
 	private:
@@ -35,6 +38,7 @@ namespace Kernel
 		void putcodepoint(uint32_t codepoint);
 		void putchar_at(uint32_t codepoint, uint32_t x, uint32_t y);
 		void render_from_buffer(uint32_t x, uint32_t y);
+		void scroll_if_needed();
 
 	private:
 		enum class State
@@ -47,11 +51,15 @@ namespace Kernel
 
 		struct AnsiState
 		{
-			int32_t nums[2]	{ -1, -1 };
-			int32_t index { 0 };
+			static constexpr size_t max_nums = 5;
+			int32_t nums[max_nums]	{ -1, -1, -1, -1, -1 };
+			size_t index { 0 };
 			bool question { false };
 		};
 
+		BAN::Optional<TerminalDriver::Color> get_8bit_color();
+		BAN::Optional<TerminalDriver::Color> get_24bit_color();
+
 		struct UTF8State
 		{
 			uint32_t codepoint { 0 };
@@ -60,14 +68,16 @@ namespace Kernel
 
 		struct Cell
 		{
-			TerminalDriver::Color foreground { TerminalColor::BRIGHT_WHITE };
-			TerminalDriver::Color background { TerminalColor::BLACK };
+			TerminalDriver::Color foreground;
+			TerminalDriver::Color background;
 			uint32_t codepoint { ' ' };
 		};
 
 	private:
 		BAN::String m_name;
 
+		BAN::RefPtr<TerminalDriver> m_terminal_driver;
+
 		State m_state { State::Normal };
 		AnsiState m_ansi_state { };
 		UTF8State m_utf8_state { };
@@ -84,11 +94,11 @@ namespace Kernel
 		uint32_t m_column { 0 };
 		Cell* m_buffer { nullptr };
 
-		TerminalDriver::Color m_foreground { TerminalColor::BRIGHT_WHITE };
-		TerminalDriver::Color m_background { TerminalColor::BLACK };
-		bool m_colors_inverted { false };
+		const Palette& m_palette;
 
-		BAN::RefPtr<TerminalDriver> m_terminal_driver;
+		TerminalDriver::Color m_foreground;
+		TerminalDriver::Color m_background;
+		bool m_colors_inverted { false };
 	};
 
 }

kernel/kernel/Debug.cpp

@@ -104,7 +104,7 @@ namespace Debug
 			{
 				if (!isprint(ch))
 					ch = '?';
-				g_terminal_driver->putchar_at(ch, col, row, TerminalColor::BRIGHT_WHITE, TerminalColor::BLACK);
+				g_terminal_driver->putchar_at(ch, col, row, TerminalColor::WHITE, TerminalColor::BLACK);
 
 				col++;
 				if (col >= g_terminal_driver->width())
@@ -121,9 +121,9 @@ namespace Debug
 			{
 				for (uint32_t i = col; i < g_terminal_driver->width(); i++)
 				{
-					g_terminal_driver->putchar_at(' ', i, row, TerminalColor::BRIGHT_WHITE, TerminalColor::BLACK);
+					g_terminal_driver->putchar_at(' ', i, row, TerminalColor::WHITE, TerminalColor::BLACK);
 					if (row + 1 < g_terminal_driver->height())
-						g_terminal_driver->putchar_at(' ', i, row + 1, TerminalColor::BRIGHT_WHITE, TerminalColor::BLACK);
+						g_terminal_driver->putchar_at(' ', i, row + 1, TerminalColor::WHITE, TerminalColor::BLACK);
 				}
 			}
 		}

kernel/kernel/Processor.cpp

@@ -360,7 +360,7 @@ namespace Kernel
 						[&x, y](char ch)
 						{
 							if (x < g_terminal_driver->width() && y < g_terminal_driver->height())
-								g_terminal_driver->putchar_at(ch, x++, y, TerminalColor::BRIGHT_WHITE, TerminalColor::BLACK);
+								g_terminal_driver->putchar_at(ch, x++, y, TerminalColor::WHITE, TerminalColor::BLACK);
 						};
 
 					BAN::Formatter::print(proc_putc, "CPU { 2}: { 3}.{3}%", current_id(), load_x1000 / 1000, load_x1000 % 1000);

kernel/kernel/Terminal/FramebufferTerminal.cpp

@@ -3,15 +3,38 @@
 namespace Kernel
 {
 
+
+	static consteval TerminalDriver::Palette default_palette()
+	{
+		TerminalDriver::Palette palette;
+		palette[ 0] = 0x000000;
+		palette[ 1] = 0xFF0000;
+		palette[ 2] = 0x00FF00;
+		palette[ 3] = 0xFFFF00;
+		palette[ 4] = 0x0000FF;
+		palette[ 5] = 0xFF00FF;
+		palette[ 6] = 0x00FFFF;
+		palette[ 7] = 0xBFBFBF;
+		palette[ 8] = 0x3F3F3F;
+		palette[ 9] = 0xFF7F7F;
+		palette[10] = 0x7FFF7F;
+		palette[11] = 0xFFFF7F;
+		palette[12] = 0x7F7FFF;
+		palette[13] = 0xFF7FFF;
+		palette[14] = 0x7FFFFF;
+		palette[15] = 0xFFFFFF;
+		return palette;
+	}
+
 	BAN::ErrorOr<BAN::RefPtr<FramebufferTerminalDriver>> FramebufferTerminalDriver::create(BAN::RefPtr<FramebufferDevice> framebuffer_device)
 	{
-		auto* driver_ptr = new FramebufferTerminalDriver(framebuffer_device);
+		auto* driver_ptr = new FramebufferTerminalDriver(framebuffer_device, default_palette());
 		if (driver_ptr == nullptr)
 			return BAN::Error::from_errno(ENOMEM);
 		auto driver = BAN::RefPtr<FramebufferTerminalDriver>::adopt(driver_ptr);
 		TRY(driver->set_font(BAN::move(TRY(LibFont::Font::prefs()))));
 		driver->set_cursor_position(0, 0);
-		driver->clear(TerminalColor::BLACK);
+		driver->clear(driver->m_palette[0]);
 		return driver;
 	}
 
@@ -60,6 +83,9 @@ namespace Kernel
 			for (uint32_t x = 0; x < m_framebuffer_device->width(); x++)
 				m_framebuffer_device->set_pixel(x, y, color.rgb);
 		m_framebuffer_device->sync_pixels_full();
+
+		if (m_cursor_shown)
+			show_cursor(false);
 	}
 
 	void FramebufferTerminalDriver::read_cursor()
@@ -78,6 +104,11 @@ namespace Kernel
 
 	void FramebufferTerminalDriver::show_cursor(bool use_data)
 	{
+		// NOTE: cursor is allowed to be on width as scrolling only
+		//       happens after character gets printed to next line
+		if (m_cursor_x == width())
+			return;
+
 		if (!use_data)
 			read_cursor();
 

kernel/kernel/Terminal/PseudoTerminal.cpp

@@ -85,16 +85,19 @@ namespace Kernel
 		return BAN::Error::from_errno(ENODEV);
 	}
 
-	void PseudoTerminalMaster::putchar(uint8_t ch)
+	bool PseudoTerminalMaster::putchar(uint8_t ch)
 	{
 		SpinLockGuard _(m_buffer_lock);
 
-		reinterpret_cast<uint8_t*>(m_buffer->vaddr())[(m_buffer_tail + m_buffer_size) % m_buffer->size()] = ch;
+		if (m_buffer_size >= m_buffer->size())
+			return false;
 
-		if (m_buffer_size < m_buffer->size())
+		reinterpret_cast<uint8_t*>(m_buffer->vaddr())[(m_buffer_tail + m_buffer_size) % m_buffer->size()] = ch;
 		m_buffer_size++;
-		else
-			m_buffer_tail = (m_buffer_tail + 1) % m_buffer->size();
+
+		m_buffer_blocker.unblock();
+
+		return true;
 	}
 
 	BAN::ErrorOr<size_t> PseudoTerminalMaster::read_impl(off_t, BAN::ByteSpan buffer)
@@ -166,10 +169,11 @@ namespace Kernel
 		(void)write_impl(0, BAN::ConstByteSpan::from(message));
 	}
 
-	void PseudoTerminalSlave::putchar_impl(uint8_t ch)
+	bool PseudoTerminalSlave::putchar_impl(uint8_t ch)
 	{
 		if (auto master = m_master.lock())
-			master->putchar(ch);
+			return master->putchar(ch);
+		return false;
 	}
 
 	BAN::ErrorOr<long> PseudoTerminalSlave::ioctl_impl(int request, void* argument)

kernel/kernel/Terminal/Serial.cpp

@@ -258,9 +258,10 @@ namespace Kernel
 		return m_serial.height();
 	}
 
-	void SerialTTY::putchar_impl(uint8_t ch)
+	bool SerialTTY::putchar_impl(uint8_t ch)
 	{
 		m_serial.putchar(ch);
+		return true;
 	}
 
 }

kernel/kernel/Terminal/TTY.cpp

@@ -327,11 +327,12 @@ namespace Kernel
 		}
 	}
 
-	void TTY::putchar(uint8_t ch)
+	bool TTY::putchar(uint8_t ch)
 	{
 		SpinLockGuard _(m_write_lock);
 		if (m_tty_ctrl.draw_graphics)
-			putchar_impl(ch);
+			return putchar_impl(ch);
+		return true;
 	}
 
 	BAN::ErrorOr<size_t> TTY::read_impl(off_t, BAN::ByteSpan buffer)
@@ -365,10 +366,12 @@ namespace Kernel
 	BAN::ErrorOr<size_t> TTY::write_impl(off_t, BAN::ConstByteSpan buffer)
 	{
 		SpinLockGuard _(m_write_lock);
-		for (size_t i = 0; i < buffer.size(); i++)
-			putchar(buffer[i]);
+		size_t written = 0;
+		for (; written < buffer.size(); written++)
+			if (!putchar(buffer[written]))
+				break;
 		update_cursor();
-		return buffer.size();
+		return written;
 	}
 
 	void TTY::putchar_current(uint8_t ch)

kernel/kernel/Terminal/TextModeTerminal.cpp

@@ -7,36 +7,39 @@
 namespace Kernel
 {
 
-	static constexpr TerminalDriver::Color s_palette[] {
-		TerminalColor::BLACK,
-		TerminalColor::BLUE,
-		TerminalColor::GREEN,
-		TerminalColor::CYAN,
-		TerminalColor::RED,
-		TerminalColor::MAGENTA,
-		TerminalColor::YELLOW,
-		TerminalColor::WHITE,
-		TerminalColor::BRIGHT_BLACK,
-		TerminalColor::BRIGHT_BLUE,
-		TerminalColor::BRIGHT_GREEN,
-		TerminalColor::BRIGHT_CYAN,
-		TerminalColor::BRIGHT_RED,
-		TerminalColor::BRIGHT_MAGENTA,
-		TerminalColor::BRIGHT_YELLOW,
-		TerminalColor::BRIGHT_WHITE,
-	};
+	static consteval TerminalDriver::Palette default_palette()
+	{
+		TerminalDriver::Palette palette;
+		palette[ 0] = 0x000000;
+		palette[ 1] = 0x0000AA;
+		palette[ 2] = 0x00AA00;
+		palette[ 3] = 0x00AAAA;
+		palette[ 4] = 0xAA0000;
+		palette[ 5] = 0xAA00AA;
+		palette[ 6] = 0xAA5500;
+		palette[ 7] = 0xAAAAAA;
+		palette[ 8] = 0x555555;
+		palette[ 9] = 0x5555FF;
+		palette[10] = 0x55FF55;
+		palette[11] = 0x55FFFF;
+		palette[12] = 0xFF5555;
+		palette[13] = 0xFF55FF;
+		palette[14] = 0xFFFF55;
+		palette[15] = 0xFFFFFF;
+		return palette;
+	}
 
 	static constexpr uint8_t color_to_text_mode_color(TerminalDriver::Color color)
 	{
 		uint32_t min_diff = BAN::numeric_limits<uint32_t>::max();
 		uint8_t closest = 0;
 
-		static_assert(sizeof(s_palette) / sizeof(*s_palette) == 16);
+		static_assert(default_palette().size() == 16);
 		for (size_t i = 0; i < 16; i++)
 		{
-			const auto rdiff = color.red()   - s_palette[i].red();
-			const auto gdiff = color.green() - s_palette[i].green();
-			const auto bdiff = color.blue()  - s_palette[i].blue();
+			const auto rdiff = color.red()   - default_palette()[i].red();
+			const auto gdiff = color.green() - default_palette()[i].green();
+			const auto bdiff = color.blue()  - default_palette()[i].blue();
 			const uint32_t diff = rdiff*rdiff + gdiff*gdiff + bdiff*bdiff;
 			if (diff >= min_diff)
 				continue;
@@ -56,7 +59,8 @@ namespace Kernel
 			g_boot_info.framebuffer.address,
 			g_boot_info.framebuffer.width,
 			g_boot_info.framebuffer.height,
-			g_boot_info.framebuffer.pitch
+			g_boot_info.framebuffer.pitch,
+			default_palette()
 		);
 		if (driver_ptr == nullptr)
 			return BAN::Error::from_errno(ENOMEM);
@@ -83,7 +87,7 @@ namespace Kernel
 		m_vaddr = vaddr + (m_paddr % PAGE_SIZE);
 
 		set_cursor_position(0, 0);
-		clear(TerminalColor::BLACK);
+		clear(m_palette[0]);
 
 		return {};
 	}
@@ -114,7 +118,7 @@ namespace Kernel
 	{
 		for (uint32_t y = 0; y < m_height; y++)
 			for (uint32_t x = 0; x < m_width; x++)
-				putchar_at(' ', x, y, TerminalColor::BRIGHT_WHITE, color);
+				putchar_at(' ', x, y, color, color);
 	}
 
 	void TextModeTerminalDriver::set_cursor_shown(bool shown)
@@ -136,6 +140,10 @@ namespace Kernel
 
 	void TextModeTerminalDriver::set_cursor_position(uint32_t x, uint32_t y)
 	{
+		// NOTE: cursor is allowed to be on width as scrolling only
+		//       happens after character gets printed to next line
+		if (x == m_width)
+			return;
 		const uint16_t pos = y * m_width + x;
 		IO::outb(0x3D4, 0x0F);
 		IO::outb(0x3D5, pos & 0xFF);

kernel/kernel/Terminal/VirtualTTY.cpp

@@ -39,6 +39,9 @@ namespace Kernel
 		: TTY(0600, 0, 0)
 		, m_name(MUST(BAN::String::formatted("tty{}", s_next_tty_number++)))
 		, m_terminal_driver(driver)
+		, m_palette(driver->palette())
+		, m_foreground(m_palette[15])
+		, m_background(m_palette[0])
 	{
 		m_width = m_terminal_driver->width();
 		m_height = m_terminal_driver->height();
@@ -95,10 +98,11 @@ namespace Kernel
 	void VirtualTTY::reset_ansi()
 	{
 		ASSERT(m_write_lock.current_processor_has_lock());
-		m_ansi_state.index = 0;
-		m_ansi_state.nums[0] = -1;
-		m_ansi_state.nums[1] = -1;
-		m_ansi_state.question = false;
+		m_ansi_state = {
+			.nums = { -1, -1, -1, -1, -1 },
+			.index = 0,
+			.question = false,
+		};
 		m_state = State::Normal;
 	}
 
@@ -108,64 +112,76 @@ namespace Kernel
 		switch (ch)
 		{
 			case 0:
-				m_foreground = TerminalColor::BRIGHT_WHITE;
-				m_background = TerminalColor::BLACK;
+				m_foreground = m_palette[15];
+				m_background = m_palette[0];
 				m_colors_inverted = false;
 				break;
 
 			case 7:  m_colors_inverted = true;  break;
 			case 27: m_colors_inverted = false; break;
 
-			case 30: m_foreground = TerminalColor::BLACK;	break;
-			case 31: m_foreground = TerminalColor::RED;		break;
-			case 32: m_foreground = TerminalColor::GREEN;	break;
-			case 33: m_foreground = TerminalColor::YELLOW;	break;
-			case 34: m_foreground = TerminalColor::BLUE;	break;
-			case 35: m_foreground = TerminalColor::MAGENTA;	break;
-			case 36: m_foreground = TerminalColor::CYAN;	break;
-			case 37: m_foreground = TerminalColor::WHITE;	break;
+			case 30: case 31: case 32: case 33: case 34: case 35: case 36: case 37:
+				m_foreground = m_palette[ch - 30];
+				break;
 
-			case 40: m_background = TerminalColor::BLACK;	break;
-			case 41: m_background = TerminalColor::RED;		break;
-			case 42: m_background = TerminalColor::GREEN;	break;
-			case 43: m_background = TerminalColor::YELLOW;	break;
-			case 44: m_background = TerminalColor::BLUE;	break;
-			case 45: m_background = TerminalColor::MAGENTA;	break;
-			case 46: m_background = TerminalColor::CYAN;	break;
-			case 47: m_background = TerminalColor::WHITE;	break;
+			case 40: case 41: case 42: case 43: case 44: case 45: case 46: case 47:
+				m_background = m_palette[ch - 40];
+				break;
 
-			case 90: m_foreground = TerminalColor::BRIGHT_BLACK;	break;
-			case 91: m_foreground = TerminalColor::BRIGHT_RED;		break;
-			case 92: m_foreground = TerminalColor::BRIGHT_GREEN;	break;
-			case 93: m_foreground = TerminalColor::BRIGHT_YELLOW;	break;
-			case 94: m_foreground = TerminalColor::BRIGHT_BLUE;		break;
-			case 95: m_foreground = TerminalColor::BRIGHT_MAGENTA;	break;
-			case 96: m_foreground = TerminalColor::BRIGHT_CYAN;		break;
-			case 97: m_foreground = TerminalColor::BRIGHT_WHITE;	break;
+			case 90: case 91: case 92: case 93: case 94: case 95: case 96: case 97:
+				m_foreground = m_palette[ch - 90 + 8];
+				break;
 
-			case 100: m_background = TerminalColor::BRIGHT_BLACK;	break;
-			case 101: m_background = TerminalColor::BRIGHT_RED;		break;
-			case 102: m_background = TerminalColor::BRIGHT_GREEN;	break;
-			case 103: m_background = TerminalColor::BRIGHT_YELLOW;	break;
-			case 104: m_background = TerminalColor::BRIGHT_BLUE;	break;
-			case 105: m_background = TerminalColor::BRIGHT_MAGENTA;	break;
-			case 106: m_background = TerminalColor::BRIGHT_CYAN;	break;
-			case 107: m_background = TerminalColor::BRIGHT_WHITE;	break;
+			case 100: case 101: case 102: case 103: case 104: case 105: case 106: case 107:
+				m_background = m_palette[ch - 100 + 8];
+				break;
 		}
 	}
 
+	BAN::Optional<TerminalDriver::Color> VirtualTTY::get_8bit_color()
+	{
+		ASSERT(m_ansi_state.nums[1] == 5);
+		if (m_ansi_state.nums[2] < 1)
+			return {};
+
+		const uint8_t code = BAN::Math::min(m_ansi_state.nums[2], 256) - 1;
+		if (code < 16)
+			return m_palette[code];
+
+		if (code < 232)
+		{
+			const uint8_t r = (code - 16) / 36 % 6 * 40 + 55;
+			const uint8_t g = (code - 16) /  6 % 6 * 40 + 55;
+			const uint8_t b = (code - 16) /  1 % 6 * 40 + 55;
+			return TerminalDriver::Color(r, g, b);
+		}
+
+		const uint8_t gray = (code - 232) * 10 + 8;
+		return TerminalDriver::Color(gray, gray, gray);
+	}
+
+	BAN::Optional<TerminalDriver::Color> VirtualTTY::get_24bit_color()
+	{
+		ASSERT(m_ansi_state.nums[1] == 2);
+		if (m_ansi_state.nums[2] < 1) return {};
+		if (m_ansi_state.nums[3] < 1) return {};
+		if (m_ansi_state.nums[4] < 1) return {};
+		const uint8_t r = BAN::Math::min(m_ansi_state.nums[2], 256) - 1;
+		const uint8_t g = BAN::Math::min(m_ansi_state.nums[3], 256) - 1;
+		const uint8_t b = BAN::Math::min(m_ansi_state.nums[4], 256) - 1;
+		return TerminalDriver::Color(r, g, b);
+	}
+
 	void VirtualTTY::handle_ansi_csi(uint8_t ch)
 	{
-		constexpr size_t max_ansi_args = sizeof(m_ansi_state.nums) / sizeof(*m_ansi_state.nums);
-
 		ASSERT(m_write_lock.current_processor_has_lock());
 		switch (ch)
 		{
 			case '0': case '1': case '2': case '3': case '4':
 			case '5': case '6': case '7': case '8': case '9':
 			{
-				if ((size_t)m_ansi_state.index >= max_ansi_args)
-					dwarnln("Only {} arguments supported with ANSI codes", max_ansi_args);
+				if (m_ansi_state.index >= m_ansi_state.max_nums)
+					dwarnln("Only {} arguments supported with ANSI codes", m_ansi_state.max_nums);
 				else
 				{
 					int32_t& val = m_ansi_state.nums[m_ansi_state.index];
@@ -174,7 +190,7 @@ namespace Kernel
 				return;
 			}
 			case ';':
-				m_ansi_state.index = BAN::Math::min<size_t>(m_ansi_state.index + 1, max_ansi_args);
+				m_ansi_state.index = BAN::Math::min<size_t>(m_ansi_state.index + 1, m_ansi_state.max_nums);
 				return;
 			case 'A': // Cursor Up
 				if (m_ansi_state.nums[0] == -1)
@@ -306,7 +322,22 @@ namespace Kernel
 				dprintln_if(DEBUG_VTTY, "Unsupported ANSI CSI character f");
 				return;
 			case 'm':
-				for (int i = 0; i <= m_ansi_state.index && i < static_cast<int>(max_ansi_args); i++)
+				if (m_ansi_state.nums[0] == 38 || m_ansi_state.nums[0] == 48)
+				{
+					if (m_ansi_state.nums[1] != 5 && m_ansi_state.nums[1] != 2)
+					{
+						reset_ansi();
+						dprintln_if(DEBUG_VTTY, "Unsupported ANSI SGR {}", m_ansi_state.nums[1]);
+						return;
+					}
+					const auto color = (m_ansi_state.nums[1] == 5)
+						? get_8bit_color()
+						: get_24bit_color();
+					if (color.has_value())
+						(m_ansi_state.nums[0] == 38 ? m_foreground : m_background) = *color;
+					return reset_ansi();
+				}
+				for (size_t i = 0; i <= m_ansi_state.index && i < m_ansi_state.max_nums; i++)
 					handle_ansi_csi_color(BAN::Math::max(m_ansi_state.nums[i], 0));
 				return reset_ansi();
 			case 's':
@@ -401,6 +432,29 @@ namespace Kernel
 		m_terminal_driver->putchar_at(codepoint, x, y, cell.foreground, cell.background);
 	}
 
+	void VirtualTTY::scroll_if_needed()
+	{
+		while (m_row >= m_height)
+		{
+			memmove(m_buffer, m_buffer + m_width, m_width * (m_height - 1) * sizeof(Cell));
+
+			// Clear last line in buffer
+			for (uint32_t x = 0; x < m_width; x++)
+				m_buffer[(m_height - 1) * m_width + x] = { .foreground = m_foreground, .background = m_background, .codepoint = ' ' };
+
+			if (!m_terminal_driver->scroll(m_background))
+			{
+				// No fast scrolling, render the whole buffer to the screen
+				for (uint32_t y = 0; y < m_height; y++)
+					for (uint32_t x = 0; x < m_width; x++)
+						render_from_buffer(x, y);
+			}
+
+			m_column = 0;
+			m_row--;
+		}
+	}
+
 	void VirtualTTY::putcodepoint(uint32_t codepoint)
 	{
 		ASSERT(m_write_lock.current_processor_has_lock());
@@ -432,40 +486,22 @@ namespace Kernel
 				m_state = State::WaitingAnsiEscape;
 				break;
 			default:
+				if (m_column >= m_width)
+				{
+					m_column = 0;
+					m_row++;
+				}
+				scroll_if_needed();
 				putchar_at(codepoint, m_column, m_row);
 				m_last_graphic_char = codepoint;
 				m_column++;
 				break;
 		}
 
-		if (m_column >= m_width)
-		{
-			m_column = 0;
-			m_row++;
+		scroll_if_needed();
 	}
 
-		while (m_row >= m_height)
-		{
-			memmove(m_buffer, m_buffer + m_width, m_width * (m_height - 1) * sizeof(Cell));
-
-			// Clear last line in buffer
-			for (uint32_t x = 0; x < m_width; x++)
-				m_buffer[(m_height - 1) * m_width + x] = { .foreground = m_foreground, .background = m_background, .codepoint = ' ' };
-
-			if (!m_terminal_driver->scroll(m_background))
-			{
-				// No fast scrolling, render the whole buffer to the screen
-				for (uint32_t y = 0; y < m_height; y++)
-					for (uint32_t x = 0; x < m_width; x++)
-						render_from_buffer(x, y);
-			}
-
-			m_column = 0;
-			m_row--;
-		}
-	}
-
-	void VirtualTTY::putchar_impl(uint8_t ch)
+	bool VirtualTTY::putchar_impl(uint8_t ch)
 	{
 		ASSERT(m_write_lock.current_processor_has_lock());
 
@@ -495,10 +531,10 @@ namespace Kernel
 				{
 					reset_ansi();
 					dprintln_if(DEBUG_VTTY, "invalid utf8");
-					return;
+					return true;
 				}
 				m_state = State::WaitingUTF8;
-				return;
+				return true;
 			case State::WaitingAnsiEscape:
 				if (ch == CSI)
 					m_state = State::WaitingAnsiCSI;
@@ -507,21 +543,21 @@ namespace Kernel
 					reset_ansi();
 					dprintln_if(DEBUG_VTTY, "unsupported byte after ansi escape {2H}", (uint8_t)ch);
 				}
-				return;
+				return true;
 			case State::WaitingAnsiCSI:
 				handle_ansi_csi(ch);
-				return;
+				return true;
 			case State::WaitingUTF8:
 				if ((ch & 0xC0) != 0x80)
 				{
 					m_state = State::Normal;
 					dprintln_if(DEBUG_VTTY, "invalid utf8");
-					return;
+					return true;
 				}
 				m_utf8_state.codepoint = (m_utf8_state.codepoint << 6) | (ch & 0x3F);
 				m_utf8_state.bytes_missing--;
 				if (m_utf8_state.bytes_missing)
-					return;
+					return true;
 				m_state = State::Normal;
 				codepoint = m_utf8_state.codepoint;
 				break;
@@ -530,6 +566,7 @@ namespace Kernel
 		}
 
 		putcodepoint(codepoint);
+		return true;
 	}
 
 	void VirtualTTY::update_cursor()

userspace/programs/Terminal/Terminal.cpp

@@ -185,6 +185,8 @@ void Terminal::run()
 
 void Terminal::hide_cursor()
 {
+	if (m_cursor.x == cols())
+		return;
 	const uint32_t cursor_base_x = m_cursor.x * m_font.width();
 	const uint32_t cursor_base_y = m_cursor.y * m_font.height();
 	for (uint32_t y = 0; y < m_font.height(); y++)
@@ -195,6 +197,8 @@ void Terminal::hide_cursor()
 
 void Terminal::show_cursor()
 {
+	if (m_cursor.x == cols())
+		return;
 	const uint32_t cursor_base_x = m_cursor.x * m_font.width();
 	const uint32_t cursor_base_y = m_cursor.y * m_font.height();
 	for (uint32_t y = 0; y < m_font.height(); y++)
@@ -321,6 +325,42 @@ void Terminal::handle_sgr(int32_t value)
 	}
 }
 
+BAN::Optional<uint32_t> Terminal::get_8bit_color()
+{
+	ASSERT(m_csi_info.fields[1] == 5);
+	if (m_csi_info.fields[2] < 1)
+		return {};
+
+	const uint8_t code = BAN::Math::min(m_csi_info.fields[2], 256) - 1;
+	if (code < 8)
+		return s_colors_dark[code];
+	if (code < 16)
+		return s_colors_bright[code - 8];
+
+	if (code < 232)
+	{
+		const uint8_t r = (code - 16) / 36 % 6 * 40 + 55;
+		const uint8_t g = (code - 16) /  6 % 6 * 40 + 55;
+		const uint8_t b = (code - 16) /  1 % 6 * 40 + 55;
+		return b | (g << 8) | (r << 16) | (0xCC << 24);
+	}
+
+	const uint8_t gray = (code - 232) * 10 + 8;
+	return gray | (gray << 8) | (gray << 16) | (0xCC << 24);
+}
+
+BAN::Optional<uint32_t> Terminal::get_24bit_color()
+{
+	ASSERT(m_csi_info.fields[1] == 2);
+	if (m_csi_info.fields[2] < 1) return {};
+	if (m_csi_info.fields[3] < 1) return {};
+	if (m_csi_info.fields[4] < 1) return {};
+	const uint8_t r = BAN::Math::min(m_csi_info.fields[2], 256) - 1;
+	const uint8_t g = BAN::Math::min(m_csi_info.fields[3], 256) - 1;
+	const uint8_t b = BAN::Math::min(m_csi_info.fields[4], 256) - 1;
+	return b | (g << 8) | (r << 16) | (0xCC << 24);
+}
+
 Rectangle Terminal::handle_csi(char ch)
 {
 	if (ch == ';')
@@ -504,6 +544,20 @@ Rectangle Terminal::handle_csi(char ch)
 			m_cursor.y = BAN::Math::clamp<int32_t>(m_csi_info.fields[0], 1, rows()) - 1;
 			break;
 		case 'm':
+			if (m_csi_info.fields[0] == 38 || m_csi_info.fields[0] == 48)
+			{
+				if (m_csi_info.fields[1] != 5 && m_csi_info.fields[1] != 2)
+				{
+					dprintln("unsupported ANSI SGR {}", m_csi_info.fields[1]);
+					break;
+				}
+				const auto color = (m_csi_info.fields[1] == 5)
+					? get_8bit_color()
+					: get_24bit_color();
+				if (color.has_value())
+					(m_csi_info.fields[0] == 38 ? m_fg_color : m_bg_color) = *color;
+				break;
+			}
 			for (size_t i = 0; i <= m_csi_info.index && i < m_csi_info.max_fields; i++)
 				handle_sgr(m_csi_info.fields[i]);
 			break;
@@ -563,6 +617,20 @@ Rectangle Terminal::putcodepoint(uint32_t codepoint)
 			break;
 		default:
 		{
+			if (m_cursor.x >= cols())
+			{
+				m_cursor.x = 0;
+				m_cursor.y++;
+			}
+
+			if (m_cursor.y >= rows())
+			{
+				const uint32_t scroll = m_cursor.y - rows() + 1;
+				m_cursor.y -= scroll;
+				m_window->shift_vertical(-scroll * (int32_t)m_font.height(), m_bg_color);
+				should_invalidate = { 0, 0, m_window->width(), m_window->height() };
+			}
+
 			const uint32_t cell_w = m_font.width();
 			const uint32_t cell_h = m_font.height();
 			const uint32_t cell_x = m_cursor.x * cell_w;
@@ -580,12 +648,6 @@ Rectangle Terminal::putcodepoint(uint32_t codepoint)
 		}
 	}
 
-	if (m_cursor.x >= cols())
-	{
-		m_cursor.x = 0;
-		m_cursor.y++;
-	}
-
 	if (m_cursor.y >= rows())
 	{
 		const uint32_t scroll = m_cursor.y - rows() + 1;
@@ -608,10 +670,11 @@ Rectangle Terminal::putchar(uint8_t ch)
 			return {};
 		}
 		m_state = State::CSI;
-		m_csi_info.index = 0;
-		m_csi_info.fields[0] = -1;
-		m_csi_info.fields[1] = -1;
-		m_csi_info.question = false;
+		m_csi_info = {
+			.fields = { -1, -1, -1, -1, -1 },
+			.index = 0,
+			.question = false,
+		};
 		return {};
 	}
 

userspace/programs/Terminal/Terminal.h

@@ -41,6 +41,9 @@ private:
 	Rectangle putchar(uint8_t ch);
 	bool read_shell();
 
+	BAN::Optional<uint32_t> get_8bit_color();
+	BAN::Optional<uint32_t> get_24bit_color();
+
 	void hide_cursor();
 	void show_cursor();
 
@@ -70,7 +73,7 @@ private:
 
 	struct CSIInfo
 	{
-		static constexpr size_t max_fields = 2;
+		static constexpr size_t max_fields = 5;
 		int32_t fields[max_fields];
 		size_t index;
 		bool question;