bootloader: restore color boot output (lost on 1.0.0 rebase)

Re-adds the TextColor enum + Os::set_text_color (no-op default, VGA fg
override for BIOS, EFI SetAttribute for UEFI) and colors the default-resolution
message green + the autoboot countdown yellow. The countdown + default
1280x720 were already present; only the color mechanism was lost when the
bootloader was rebased to upstream 1.0.0 (the color commits stayed on
bootloader-detached-pending).

src/main.rs

@@ -17,7 +17,7 @@ use core::{
 use redoxfs::{Disk, Node, TreeData};
 
 use self::arch::{paging_create, paging_framebuffer};
-use self::os::{Os, OsHwDesc, OsKey, OsMemoryEntry, OsMemoryKind, OsVideoMode};
+use self::os::{Os, OsHwDesc, OsKey, OsMemoryEntry, OsMemoryKind, OsVideoMode, TextColor};
 
 #[macro_use]
 mod os;
@@ -154,7 +154,9 @@ fn select_mode(
         if mode.width == DEFAULT_WIDTH && mode.height == DEFAULT_HEIGHT {
             selected = mode.id;
             selected_from_default = true;
+            os.set_text_color(TextColor::Green);
             print!(", default resolution: {}x{}", DEFAULT_WIDTH, DEFAULT_HEIGHT);
+            os.set_text_color(TextColor::Default);
             break;
         }
     }
@@ -212,10 +214,12 @@ fn select_mode(
         os.set_text_position(0, countdown_y);
         os.set_text_highlight(false);
         if countdown_active {
+            os.set_text_color(TextColor::Yellow);
             println!(
                 "Autobooting default mode in {} seconds (press any key to cancel countdown)",
                 countdown
             );
+            os.set_text_color(TextColor::Default);
         } else {
             println!("Manual mode selection active. Press Enter to boot selected mode.      ");
         }

src/os/bios/mod.rs

@@ -4,7 +4,7 @@ use linked_list_allocator::LockedHeap;
 use spin::Mutex;
 
 use crate::logger::LOGGER;
-use crate::os::{Os, OsHwDesc, OsKey, OsVideoMode};
+use crate::os::{Os, OsHwDesc, OsKey, OsVideoMode, TextColor};
 use crate::KernelArgs;
 
 use self::disk::DiskBios;
@@ -284,6 +284,18 @@ impl Os for OsBios {
         vga.y = y;
     }
 
+    fn set_text_color(&self, color: TextColor) {
+        let mut vga = VGA.lock();
+        vga.bg = VgaTextColor::Black;
+        vga.fg = match color {
+            TextColor::Default | TextColor::White => VgaTextColor::White,
+            TextColor::Red => VgaTextColor::LightRed,
+            TextColor::Green => VgaTextColor::LightGreen,
+            TextColor::Yellow => VgaTextColor::Yellow,
+            TextColor::Cyan => VgaTextColor::LightCyan,
+        };
+    }
+
     fn set_text_highlight(&self, highlight: bool) {
         let mut vga = VGA.lock();
         if highlight {

src/os/mod.rs

@@ -36,6 +36,17 @@ pub enum OsKey {
     Other,
 }
 
+/// Text colors for bootloader console output (restored Red Bear feature).
+#[derive(Clone, Copy, Debug)]
+pub enum TextColor {
+    Default,
+    Red,
+    Green,
+    Yellow,
+    Cyan,
+    White,
+}
+
 // Keep synced with BootloaderMemoryKind in kernel
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 #[repr(u64)]
@@ -96,4 +107,6 @@ pub trait Os {
     fn get_text_position(&self) -> (usize, usize);
     fn set_text_position(&self, x: usize, y: usize);
     fn set_text_highlight(&self, highlight: bool);
+    /// Set the console foreground color. Default is a no-op; backends override.
+    fn set_text_color(&self, _color: TextColor) {}
 }

src/os/uefi/mod.rs

@@ -11,7 +11,7 @@ use uefi::{
     Handle,
 };
 
-use crate::os::{Os, OsHwDesc, OsKey, OsVideoMode};
+use crate::os::{Os, OsHwDesc, OsKey, OsVideoMode, TextColor};
 
 use self::{
     device::{device_path_to_string, disk_device_priority},
@@ -393,6 +393,18 @@ impl Os for OsEfi {
         ));
     }
 
+    fn set_text_color(&self, color: TextColor) {
+        let attr = match color {
+            TextColor::Default => 0x07,
+            TextColor::White => 0x0F,
+            TextColor::Red => 0x0C,
+            TextColor::Green => 0x0A,
+            TextColor::Yellow => 0x0E,
+            TextColor::Cyan => 0x0B,
+        };
+        status_to_result((self.st.ConsoleOut.SetAttribute)(self.st.ConsoleOut, attr)).unwrap();
+    }
+
     fn set_text_highlight(&self, highlight: bool) {
         let attr = if highlight { 0x70 } else { 0x07 };
         status_to_result((self.st.ConsoleOut.SetAttribute)(self.st.ConsoleOut, attr)).unwrap();