wind: Add a simple display server skeleton using libui

No client functionality yet, but it's a start.

CMakeLists.txt

@@ -51,3 +51,4 @@ add_subdirectory(kernel)
 add_subdirectory(apps)
 add_subdirectory(tests)
 add_subdirectory(shell)
+add_subdirectory(wind)

wind/CMakeLists.txt

@@ -0,0 +1,14 @@
+set(SOURCES
+    main.cpp
+    Screen.h
+    Screen.cpp
+    Mouse.h
+    Mouse.cpp
+)
+
+add_executable(wind ${SOURCES})
+target_compile_options(wind PRIVATE -Os ${COMMON_FLAGS} -Wno-write-strings)
+add_dependencies(wind libc)
+target_include_directories(wind PRIVATE ${LUNA_BASE}/usr/include ${CMAKE_CURRENT_LIST_DIR})
+target_link_libraries(wind PRIVATE os ui)
+install(TARGETS wind DESTINATION ${LUNA_BASE}/usr/bin)

wind/Mouse.cpp

@@ -0,0 +1,21 @@
+#include "Mouse.h"
+
+Mouse::Mouse(ui::Canvas& screen)
+{
+    m_position.x = screen.width / 2;
+    m_position.y = screen.height / 2;
+    m_screen_rect = screen.rect();
+}
+
+void Mouse::draw(ui::Canvas& screen)
+{
+    auto canvas = screen.subcanvas(m_position, 10, 10, true).release_value();
+    canvas.fill(ui::WHITE);
+}
+
+void Mouse::move(const moon::MousePacket& packet)
+{
+    m_position.x += packet.xdelta;
+    m_position.y -= packet.ydelta;
+    m_position = m_screen_rect.normalize(m_position);
+}

wind/Mouse.h

@@ -0,0 +1,18 @@
+#pragma once
+#include "Screen.h"
+#include <moon/Mouse.h>
+#include <ui/Canvas.h>
+
+class Mouse
+{
+  public:
+    Mouse(ui::Canvas& screen);
+
+    void move(const moon::MousePacket& packet);
+
+    void draw(ui::Canvas& screen);
+
+  private:
+    ui::Point m_position;
+    ui::Rect m_screen_rect;
+};

wind/Screen.cpp

@@ -0,0 +1,34 @@
+#include "Screen.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+Result<Screen> Screen::open()
+{
+    int fd = ::open("/dev/fb0", O_RDWR | O_CLOEXEC);
+    if (fd < 0) return err(errno);
+
+    int width = ioctl(fd, FB_GET_WIDTH);
+    int height = ioctl(fd, FB_GET_HEIGHT);
+
+    void* p = mmap(nullptr, width * height * BYTES_PER_PIXEL, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+    if (p == MAP_FAILED)
+    {
+        close(fd);
+        return err(errno);
+    }
+
+    Screen screen;
+
+    screen.m_canvas = ui::Canvas::create((u8*)p, width, height);
+    screen.m_size = width * height * BYTES_PER_PIXEL;
+
+    return screen;
+}
+
+void Screen::sync()
+{
+    msync(m_canvas.ptr, size(), MS_SYNC);
+}

wind/Screen.h

@@ -0,0 +1,27 @@
+#pragma once
+#include <luna/OwnedPtr.h>
+#include <ui/Canvas.h>
+
+constexpr int BYTES_PER_PIXEL = 4;
+
+class Screen
+{
+  public:
+    static Result<Screen> open();
+
+    ui::Canvas& canvas()
+    {
+        return m_canvas;
+    }
+
+    int size() const
+    {
+        return m_size;
+    }
+
+    void sync();
+
+  private:
+    ui::Canvas m_canvas;
+    int m_size;
+};

wind/main.cpp

@@ -0,0 +1,98 @@
+#include "Mouse.h"
+#include "Screen.h"
+#include <errno.h>
+#include <moon/Keyboard.h>
+#include <os/ArgumentParser.h>
+#include <os/File.h>
+#include <pwd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/poll.h>
+#include <unistd.h>
+
+Result<int> luna_main(int argc, char** argv)
+{
+    StringView socket_path = "/tmp/wind.sock";
+    StringView user;
+
+    os::ArgumentParser parser;
+    parser.add_description("The display server for Luna's graphical user interface."_sv);
+    parser.add_system_program_info("wind"_sv);
+    parser.add_value_argument(socket_path, 's', "socket"_sv, "the path for the local IPC socket"_sv);
+    parser.add_value_argument(user, 'u', "user"_sv, "the user to run as"_sv);
+    parser.parse(argc, argv);
+
+    if (geteuid() != 0)
+    {
+        os::eprintln("error: wind must be run as root to initialize resources, run with --user=<USERNAME> to drop "
+                     "privileges afterwards");
+        return 1;
+    }
+
+    auto mouse = TRY(os::File::open("/dev/mouse", os::File::ReadOnly));
+    mouse->set_buffer(os::File::NotBuffered);
+    mouse->set_close_on_exec();
+
+    auto keyboard = TRY(os::File::open("/dev/kbd", os::File::ReadOnly));
+    keyboard->set_buffer(os::File::NotBuffered);
+    keyboard->set_close_on_exec();
+
+    auto screen = TRY(Screen::open());
+
+    Mouse mouse_pointer { screen.canvas() };
+
+    ioctl(STDIN_FILENO, TTYSETGFX, 1);
+
+    setpgid(0, 0);
+
+    int fd = open("/dev/null", O_RDONLY);
+    if (fd >= 0)
+    {
+        dup2(fd, STDIN_FILENO);
+        close(fd);
+    }
+
+    clearenv();
+
+    if (!user.is_empty())
+    {
+        auto* pwd = getpwnam(user.chars());
+        if (pwd)
+        {
+            setgid(pwd->pw_gid);
+            setuid(pwd->pw_uid);
+        }
+    }
+
+    ui::Color background = ui::BLACK;
+
+    while (1)
+    {
+        struct pollfd fds[] = {
+            { .fd = mouse->fd(), .events = POLLIN, .revents = 0 },
+            { .fd = keyboard->fd(), .events = POLLIN, .revents = 0 },
+        };
+
+        int rc = poll(fds, 2, 1000);
+        if (!rc) continue;
+        if (rc < 0) { os::println("poll: error: %s", strerror(errno)); }
+
+        if (fds[0].revents & POLLIN)
+        {
+            moon::MousePacket packet;
+            TRY(mouse->read_typed(packet));
+            mouse_pointer.move(packet);
+        }
+        if (fds[1].revents & POLLIN)
+        {
+            moon::KeyboardPacket packet;
+            TRY(keyboard->read_typed(packet));
+            background = ui::Color::from_rgb(0x00, 0x00, packet.key * 2);
+        }
+
+        screen.canvas().fill(background);
+        mouse_pointer.draw(screen.canvas());
+        screen.sync();
+    }
+}