feat(userspace): terminal server + shell desktop; US keymap w/ shift; libkos allocator multi-page fix; panics print

crates/servers/terminal-server/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "terminal-server"
+version = "0.1.0"
+edition = "2024"
+
+[[bin]]
+name = "terminal-server"
+test = false
+bench = false
+
+[dependencies]
+types = { workspace = true }
+libkos = { workspace = true }
+server-framework = { workspace = true }

crates/servers/terminal-server/src/grid.rs

@@ -0,0 +1,89 @@
+//! The terminal's text: a grid of cells, a cursor, and which rows changed.
+
+use alloc::vec;
+use alloc::vec::Vec;
+
+pub const MAX_COLS: usize = 160;
+pub const MAX_ROWS: usize = 64;
+
+/// On the heap: a full screen is more than a program stack holds.
+pub struct Grid {
+    cells: Vec<u8>,
+    cols: usize,
+    rows: usize,
+    pub col: usize,
+    pub row: usize,
+    /// Rows to redraw.
+    dirty: Vec<bool>,
+}
+
+impl Grid {
+    pub fn new(cols: usize, rows: usize) -> Self {
+        let (cols, rows) = (cols.clamp(1, MAX_COLS), rows.clamp(1, MAX_ROWS));
+        Self { cells: vec![b' '; cols * rows], cols, rows, col: 0, row: 0, dirty: vec![true; rows] }
+    }
+
+    pub fn row(&self, r: usize) -> &[u8] {
+        &self.cells[r * self.cols..(r + 1) * self.cols]
+    }
+
+    pub fn rows(&self) -> usize {
+        self.rows
+    }
+
+    /// The rows changed since the last call, each once.
+    pub fn take_dirty(&mut self) -> impl Iterator<Item = usize> + '_ {
+        let rows = self.rows;
+        self.dirty[..rows].iter_mut().enumerate().filter_map(|(r, d)| core::mem::take(d).then_some(r))
+    }
+
+    fn mark(&mut self, r: usize) {
+        self.dirty[r] = true;
+    }
+
+    fn newline(&mut self) {
+        // The row the cursor leaves, so its cursor cell is redrawn.
+        self.mark(self.row);
+        self.col = 0;
+        if self.row + 1 < self.rows {
+            self.row += 1;
+            return;
+        }
+        // At the bottom: everything moves up a row.
+        self.cells.copy_within(self.cols.., 0);
+        let last = (self.rows - 1) * self.cols;
+        self.cells[last..].fill(b' ');
+        self.dirty.fill(true);
+    }
+
+    /// Writes one byte at the cursor: `\n` moves to the next line, other
+    /// bytes wrap at the right edge.
+    pub fn put(&mut self, b: u8) {
+        if b == b'\n' {
+            self.newline();
+            return;
+        }
+        if self.col == self.cols {
+            self.newline();
+        }
+        self.cells[self.row * self.cols + self.col] = b;
+        self.mark(self.row);
+        self.col += 1;
+    }
+
+    /// Erases the cell before the cursor, on this row only.
+    pub fn back(&mut self) {
+        if self.col > 0 {
+            self.col -= 1;
+            self.cells[self.row * self.cols + self.col] = b' ';
+            self.mark(self.row);
+        }
+    }
+
+    pub fn clear(&mut self) {
+        self.cells.fill(b' ');
+        self.col = 0;
+        self.row = 0;
+        self.dirty.fill(true);
+    }
+}

crates/servers/terminal-server/src/lib.rs

@@ -0,0 +1,90 @@
+#![no_std]
+
+extern crate alloc;
+
+pub mod grid;
+pub mod server;
+
+#[cfg(test)]
+#[path = "tests/mod.rs"]
+mod tests;
+
+use libkos::display::{self, CELL_HEIGHT, CELL_WIDTH};
+use libkos::input::{InputEvent, Key};
+use libkos::syscall;
+use types::bounded::CapSlot;
+use types::display::{Color, ScreenCoord};
+
+/// Where init put them (its manifest: own endpoint, then `uses`).
+const EP: CapSlot = CapSlot::const_new(0);
+const DISPLAY: CapSlot = CapSlot::const_new(1);
+
+const FG: Color = Color::rgb(220, 220, 220);
+const BG: Color = Color::rgb(16, 16, 24);
+/// Output is shown at most this long after it is written. The timebase is
+/// QEMU virt's 10 MHz.
+const FLUSH_DELAY: u64 = 20 * 10_000;
+
+struct Screen {
+    keys: CapSlot,
+    /// Bound to the serving thread; the flush timer signals it.
+    timer: CapSlot,
+}
+
+fn at(col: usize, row: usize) -> (ScreenCoord, ScreenCoord) {
+    (ScreenCoord::new((col * CELL_WIDTH) as u16), ScreenCoord::new((row * CELL_HEIGHT) as u16))
+}
+
+impl server::Console for Screen {
+    fn draw_row(&mut self, row: usize, text: &[u8]) {
+        let (x, y) = at(0, row);
+        display::draw_text(DISPLAY, x, y, FG, BG, text);
+    }
+
+    fn draw_cursor(&mut self, col: usize, row: usize, under: u8) {
+        let (x, y) = at(col, row);
+        display::draw_text(DISPLAY, x, y, BG, FG, &[under]);
+    }
+
+    fn flush(&mut self) {
+        display::flush(DISPLAY);
+    }
+
+    fn flush_later(&mut self) {
+        let at = syscall::get_time().raw() + FLUSH_DELAY;
+        let _ = syscall::set_timer(self.timer, types::time::Ticks::from_raw(at));
+    }
+
+    fn next_key(&mut self) -> u8 {
+        loop {
+            while let Some(event) = display::poll_input(DISPLAY) {
+                let InputEvent::KeyDown(key) = event else { continue };
+                match key {
+                    Key::Char(c) => return c,
+                    Key::Space | Key::Tab => return b' ',
+                    Key::Enter => return b'\n',
+                    Key::Backspace => return server::BACKSPACE,
+                    _ => {}
+                }
+            }
+            let _ = syscall::wait(self.keys);
+        }
+    }
+}
+
+pub fn run() -> ! {
+    let Some(keys) = display::subscribe_input(DISPLAY) else {
+        libkos::println!("terminal: no input focus, exiting");
+        syscall::exit();
+    };
+    let Some(timer) = syscall::create_notification().ok().filter(|t| syscall::bind_notification(*t).is_ok()) else {
+        libkos::println!("terminal: no timer notification, exiting");
+        syscall::exit();
+    };
+    let (w, h) = display::get_dimensions(DISPLAY);
+    display::clear(DISPLAY, BG);
+    let cols = w.raw() as usize / CELL_WIDTH;
+    let rows = h.raw() as usize / CELL_HEIGHT;
+    let mut srv = server::TerminalServer::new(Screen { keys, timer }, cols, rows);
+    server_framework::serve(&mut srv, EP)
+}

crates/servers/terminal-server/src/main.rs

@@ -0,0 +1,9 @@
+#![no_std]
+#![no_main]
+
+extern crate libkos;
+
+#[unsafe(no_mangle)]
+extern "C" fn main() {
+    terminal_server::run();
+}

crates/servers/terminal-server/src/server.rs

@@ -0,0 +1,184 @@
+//! Text out (the log protocol) and lines in, on a screen and keyboard
+//! behind `Console`.
+
+use server_framework::{Encode, MALFORMED, Server};
+use types::bounded::CapSlot;
+use types::log::{TEXT_BYTES, text_of, text_words};
+
+use crate::grid::Grid;
+
+/// What the terminal draws on and reads from.
+pub trait Console {
+    fn draw_row(&mut self, row: usize, text: &[u8]);
+    /// Shows the cursor at a cell, over what `draw_row` drew there.
+    fn draw_cursor(&mut self, col: usize, row: usize, under: u8);
+    fn flush(&mut self);
+    /// Soon calls `TerminalServer::signal`, to flush a burst of output once.
+    fn flush_later(&mut self);
+    /// Blocks until a key is typed: a byte, `\n` for Enter, 8 for Backspace.
+    fn next_key(&mut self) -> u8;
+}
+
+pub const BACKSPACE: u8 = 8;
+const MAX_LINE: usize = 256;
+
+pub struct TerminalServer<C: Console> {
+    console: C,
+    grid: Grid,
+    /// A typed line not yet handed out in full, and how much of it was.
+    line: [u8; MAX_LINE],
+    line_len: usize,
+    line_read: usize,
+    flush_pending: bool,
+}
+
+/// An empty reply, whose tag is not text.
+pub struct Done;
+
+impl Encode for Done {
+    fn encode(&self) -> [usize; 4] {
+        [0; 4]
+    }
+}
+
+impl<C: Console> TerminalServer<C> {
+    pub fn new(console: C, cols: usize, rows: usize) -> Self {
+        let mut s = Self {
+            console,
+            grid: Grid::new(cols, rows),
+            line: [0; MAX_LINE],
+            line_len: 0,
+            line_read: 0,
+            flush_pending: false,
+        };
+        s.redraw();
+        s.console.flush();
+        s
+    }
+
+    pub fn console(&self) -> &C {
+        &self.console
+    }
+
+    pub fn grid(&self) -> &Grid {
+        &self.grid
+    }
+
+    fn redraw(&mut self) {
+        let mut dirty = [false; crate::grid::MAX_ROWS];
+        for r in self.grid.take_dirty() {
+            dirty[r] = true;
+        }
+        for (r, _) in dirty.iter().enumerate().filter(|(_, d)| **d) {
+            self.console.draw_row(r, self.grid.row(r));
+        }
+        let (col, row) = (self.grid.col, self.grid.row);
+        let under = self.grid.row(row).get(col).copied().unwrap_or(b' ');
+        self.console.draw_cursor(col, row, under);
+    }
+
+    fn write(&mut self, bytes: &[u8]) {
+        for &b in bytes {
+            self.grid.put(b);
+        }
+        self.redraw();
+        if !self.flush_pending {
+            self.flush_pending = true;
+            self.console.flush_later();
+        }
+    }
+
+    /// Edits a line from the keyboard, echoing it, until Enter.
+    fn read_line(&mut self) {
+        self.console.flush();
+        self.line_len = 0;
+        self.line_read = 0;
+        loop {
+            match self.console.next_key() {
+                b'\n' => {
+                    self.line[self.line_len] = b'\n';
+                    self.line_len += 1;
+                    self.grid.put(b'\n');
+                    break;
+                }
+                BACKSPACE if self.line_len > 0 => {
+                    self.line_len -= 1;
+                    self.grid.back();
+                }
+                BACKSPACE => continue,
+                // Room is kept for the closing newline.
+                b if self.line_len + 1 < MAX_LINE && (b' '..=b'~').contains(&b) => {
+                    self.line[self.line_len] = b;
+                    self.line_len += 1;
+                    self.grid.put(b);
+                }
+                _ => continue,
+            }
+            self.redraw();
+            self.console.flush();
+        }
+        self.redraw();
+        self.console.flush();
+    }
+
+    /// The next chunk of the typed line, reading one first if none is left.
+    fn read(&mut self) -> [usize; 4] {
+        if self.line_read == self.line_len {
+            self.read_line();
+        }
+        let end = (self.line_read + TEXT_BYTES).min(self.line_len);
+        let chunk = &self.line[self.line_read..end];
+        self.line_read = end;
+        text_words(chunk)
+    }
+}
+
+impl<C: Console> Server for TerminalServer<C> {
+    type Request = Request;
+    type Response = Done;
+
+    fn handle(&mut self, request: Request) -> Done {
+        match request {
+            Request::Clear => {
+                self.grid.clear();
+                self.redraw();
+                self.console.flush();
+            }
+        }
+        Done
+    }
+
+    fn handle_call(&mut self, _badge: usize, words: [usize; 4], _cap: Option<CapSlot>) -> ([usize; 4], Option<CapSlot>) {
+        let reply = match words[0] {
+            types::terminal::READ => self.read(),
+            types::terminal::CLEAR => {
+                self.handle(Request::Clear);
+                [0; 4]
+            }
+            _ => match text_of(words) {
+                Some((bytes, len)) => {
+                    self.write(&bytes[..len]);
+                    [0; 4]
+                }
+                None => [MALFORMED, 0, 0, 0],
+            },
+        };
+        (reply, None)
+    }
+
+    /// The flush timer: show a burst of output in one frame.
+    fn signal(&mut self, _bits: usize) {
+        self.flush_pending = false;
+        self.console.flush();
+    }
+}
+
+pub enum Request {
+    Clear,
+}
+
+impl server_framework::Decode for Request {
+    fn decode(words: [usize; 4]) -> Option<Self> {
+        (words[0] == types::terminal::CLEAR).then_some(Request::Clear)
+    }
+}

crates/servers/terminal-server/src/tests/grid.rs

@@ -0,0 +1,38 @@
+use crate::grid::Grid;
+
+fn text(g: &Grid, r: usize) -> &str {
+    core::str::from_utf8(g.row(r)).unwrap().trim_end()
+}
+
+#[test]
+fn text_wraps_at_the_edge_and_newlines_move_down() {
+    let mut g = Grid::new(4, 3);
+    for b in b"abcdef\nx" {
+        g.put(*b);
+    }
+    assert_eq!((text(&g, 0), text(&g, 1), text(&g, 2)), ("abcd", "ef", "x"));
+    assert_eq!((g.col, g.row), (1, 2));
+}
+
+#[test]
+fn the_bottom_line_scrolls_everything_up() {
+    let mut g = Grid::new(4, 2);
+    for b in b"one\ntwo\nsix" {
+        g.put(*b);
+    }
+    assert_eq!((text(&g, 0), text(&g, 1)), ("two", "six"));
+    let _ = g.take_dirty().count();
+    g.put(b'\n');
+    assert_eq!(g.take_dirty().count(), 2, "a scroll redraws every row");
+}
+
+#[test]
+fn backspace_stops_at_the_row_start_and_dirty_rows_come_once() {
+    let mut g = Grid::new(4, 2);
+    g.put(b'a');
+    g.back();
+    g.back();
+    assert_eq!((text(&g, 0), g.col), ("", 0));
+    let _ = g.take_dirty().count();
+    assert_eq!(g.take_dirty().count(), 0);
+}

crates/servers/terminal-server/src/tests/mod.rs

@@ -0,0 +1,2 @@
+mod grid;
+mod server;

crates/servers/terminal-server/src/tests/server.rs

@@ -0,0 +1,70 @@
+extern crate std;
+
+use crate::server::{BACKSPACE, Console, TerminalServer};
+use server_framework::Server;
+use std::vec::Vec;
+use types::log::{text_of, text_words};
+
+#[derive(Default)]
+struct Fake {
+    keys: Vec<u8>,
+    flushes: usize,
+    timers: usize,
+}
+
+impl Console for Fake {
+    fn draw_row(&mut self, _row: usize, _text: &[u8]) {}
+    fn draw_cursor(&mut self, _col: usize, _row: usize, _under: u8) {}
+    fn flush(&mut self) {
+        self.flushes += 1;
+    }
+    fn flush_later(&mut self) {
+        self.timers += 1;
+    }
+    fn next_key(&mut self) -> u8 {
+        self.keys.remove(0)
+    }
+}
+
+fn term(keys: &[u8]) -> TerminalServer<Fake> {
+    TerminalServer::new(Fake { keys: keys.to_vec(), ..Fake::default() }, 40, 10)
+}
+
+fn read(t: &mut TerminalServer<Fake>) -> Vec<u8> {
+    let (words, _) = t.handle_call(1, [types::terminal::READ, 0, 0, 0], None);
+    let (bytes, len) = text_of(words).unwrap();
+    bytes[..len].to_vec()
+}
+
+#[test]
+fn writes_land_on_the_grid_and_flush_once_per_burst() {
+    let mut t = term(&[]);
+    let before = t.console().flushes;
+    for chunk in [&b"hello "[..], b"world"] {
+        t.handle_call(1, text_words(chunk), None);
+    }
+    assert_eq!(&t.grid().row(0)[..11], b"hello world");
+    assert_eq!((t.console().timers, t.console().flushes), (1, before));
+    t.signal(1);
+    assert_eq!(t.console().flushes, before + 1);
+}
+
+#[test]
+fn a_read_returns_the_edited_line_in_chunks() {
+    let mut keys = b"ls -lx".to_vec();
+    keys.push(BACKSPACE);
+    keys.extend_from_slice(b"a /home/someone/very/long\n");
+    let mut t = term(&keys);
+    let mut line = read(&mut t);
+    while line.last() != Some(&b'\n') {
+        line.extend(read(&mut t));
+    }
+    assert_eq!(line, b"ls -la /home/someone/very/long\n");
+    assert_eq!(&t.grid().row(0)[..6], b"ls -la");
+}
+
+#[test]
+fn backspace_on_an_empty_line_does_nothing() {
+    let mut t = term(&[BACKSPACE, b'x', b'\n']);
+    assert_eq!(read(&mut t), b"x\n");
+}