feat(boot): implement basic boot menu

hack/dev/boot.sh

@@ -35,6 +35,7 @@ set -- "${@}" -smp 2 -m 4096
 if [ "${NO_GRAPHICAL_BOOT}" = "1" ]; then
 	set -- "${@}" -nographic
 else
+	if [ "${GRAPHICAL_ONLY}" != "1" ]; then
 		if [ "${QEMU_LEGACY_SERIAL}" = "1" ]; then
 			set -- "${@}" -serial stdio
 		else
@@ -43,6 +44,7 @@ else
 				-chardev stdio,id=stdio0 \
 				-device virtconsole,chardev=stdio0,id=console0
 		fi
+	fi
 
 	if [ "${QEMU_LEGACY_VGA}" = "1" ]; then
 		set -- "${@}" -vga std

hack/dev/build.sh

@@ -11,7 +11,7 @@ if [ "${TARGET_ARCH}" = "aarch64" ]; then
 fi
 
 if [ -z "${SPROUT_CONFIG_NAME}" ]; then
-	SPROUT_CONFIG_NAME="kernel"
+	SPROUT_CONFIG_NAME="all"
 fi
 
 echo "[build] ${TARGET_ARCH} ${RUST_PROFILE}"

hack/dev/configs/all.sprout.toml

@@ -0,0 +1,30 @@
+version = 1
+
+[defaults]
+entry = "kernel"
+
+[extractors.boot.filesystem-device-match]
+has-item = "\\EFI\\BOOT\\kernel.efi"
+
+[actions.chainload-kernel]
+chainload.path = "$boot\\EFI\\BOOT\\kernel.efi"
+chainload.options = ["console=hvc0"]
+chainload.linux-initrd = "$boot\\initramfs"
+
+[entries.kernel]
+title = "Boot Linux"
+actions = ["chainload-kernel"]
+
+[actions.chainload-shell]
+chainload.path = "$boot\\EFI\\BOOT\\shell.efi"
+
+[entries.shell]
+title = "Boot Shell"
+actions = ["chainload-shell"]
+
+[actions.chainload-xen]
+chainload.path = "$boot\\EFI\\BOOT\\xen.efi"
+
+[entries.xen]
+title = "Boot Xen"
+actions = ["chainload-xen"]

hack/dev/configs/edera.sprout.toml

@@ -2,6 +2,7 @@ version = 1
 
 [defaults]
 entry = "edera"
+menu-timeout = 0
 
 [extractors.boot.filesystem-device-match]
 has-item = "\\EFI\\BOOT\\xen.efi"

hack/dev/configs/kernel.sprout.toml

@@ -2,6 +2,7 @@ version = 1
 
 [defaults]
 entry = "kernel"
+menu-timeout = 0
 
 [extractors.boot.filesystem-device-match]
 has-item = "\\EFI\\BOOT\\kernel.efi"

hack/dev/configs/shell.sprout.toml

@@ -2,6 +2,7 @@ version = 1
 
 [defaults]
 entry = "shell"
+menu-timeout = 0
 
 [extractors.boot.filesystem-device-match]
 has-item = "\\EFI\\BOOT\\shell.efi"

hack/dev/configs/xen.sprout.toml

@@ -2,6 +2,7 @@ version = 1
 
 [defaults]
 entry = "xen"
+menu-timeout = 0
 
 [extractors.boot.filesystem-device-match]
 has-item = "\\EFI\\BOOT\\xen.efi"

src/config.rs

@@ -14,6 +14,9 @@ pub mod loader;
 /// This must be incremented when the configuration breaks compatibility.
 pub const LATEST_VERSION: u32 = 1;
 
+/// The default timeout for the boot menu in seconds.
+pub const DEFAULT_MENU_TIMEOUT_SECONDS: u64 = 10;
+
 /// The Sprout configuration format.
 #[derive(Serialize, Deserialize, Default, Clone)]
 pub struct RootConfiguration {
@@ -68,8 +71,15 @@ pub struct DefaultsConfiguration {
     /// The entry to boot without showing the boot menu.
     /// If not specified, a boot menu is shown.
     pub entry: Option<String>,
+    /// The timeout of the boot menu.
+    #[serde(rename = "menu-timeout", default = "default_menu_timeout")]
+    pub menu_timeout: u64,
 }
 
 fn latest_version() -> u32 {
     LATEST_VERSION
 }
+
+fn default_menu_timeout() -> u64 {
+    DEFAULT_MENU_TIMEOUT_SECONDS
+}

src/entries.rs

@@ -27,6 +27,7 @@ pub struct BootableEntry {
     title: String,
     context: Rc<SproutContext>,
     declaration: EntryDeclaration,
+    default: bool,
 }
 
 impl BootableEntry {
@@ -42,6 +43,7 @@ impl BootableEntry {
             title,
             context,
             declaration,
+            default: false,
         }
     }
 
@@ -65,6 +67,11 @@ impl BootableEntry {
         &self.declaration
     }
 
+    /// Fetch whether the entry is the default entry.
+    pub fn is_default(&self) -> bool {
+        self.default
+    }
+
     /// Swap out the context of the entry.
     pub fn swap_context(&mut self, context: Rc<SproutContext>) {
         self.context = context;
@@ -75,8 +82,30 @@ impl BootableEntry {
         self.title = self.context.stamp(&self.title);
     }
 
+    /// Mark this entry as the default entry.
+    pub fn mark_default(&mut self) {
+        self.default = true;
+    }
+
     /// Prepend the name of the entry with `prefix`.
     pub fn prepend_name_prefix(&mut self, prefix: &str) {
         self.name.insert_str(0, prefix);
     }
+
+    /// Determine if this entry matches `needle` by comparing to the name or title of the entry.
+    pub fn is_match(&self, needle: &str) -> bool {
+        self.name == needle || self.title == needle
+    }
+
+    /// Find an entry by `needle` inside the entry iterator `haystack`.
+    /// This will search for an entry by name, title, or index.
+    pub fn find<'a>(
+        needle: &str,
+        haystack: impl Iterator<Item = &'a BootableEntry>,
+    ) -> Option<&'a BootableEntry> {
+        haystack
+            .enumerate()
+            .find(|(index, entry)| entry.is_match(needle) || index.to_string() == needle)
+            .map(|(_index, entry)| entry)
+    }
 }

src/main.rs

@@ -10,6 +10,7 @@ use anyhow::{Context, Result};
 use log::info;
 use std::collections::BTreeMap;
 use std::ops::Deref;
+use std::time::Duration;
 use uefi::proto::device_path::LoadedImageDevicePath;
 use uefi::proto::device_path::text::{AllowShortcuts, DisplayOnly};
 
@@ -34,6 +35,9 @@ pub mod extractors;
 /// generators: Runtime code that can generate entries with specific values.
 pub mod generators;
 
+/// menu: Display a boot menu to select an entry to boot.
+pub mod menu;
+
 /// phases: Hooks into specific parts of the boot process.
 pub mod phases;
 
@@ -151,41 +155,47 @@ fn main() -> Result<()> {
         entry.swap_context(context);
         // Restamp the title with any values.
         entry.restamp_title();
+
+        // Mark this entry as the default entry if it is declared as such.
+        if let Some(ref default_entry) = config.defaults.entry {
+            // If the entry matches the default entry, mark it as the default entry.
+            if entry.is_match(default_entry) {
+                entry.mark_default();
+            }
+        }
     }
 
-    // TODO(azenla): Implement boot menu here.
-    // For now, we just print all of the entries.
-    info!("entries:");
-    for (index, entry) in entries.iter().enumerate() {
-        let title = entry.context().stamp(&entry.declaration().title);
-        info!("  entry {} [{}]: {}", index, entry.name(), title);
+    // If no entries were the default, pick the first entry as the default entry.
+    if entries.iter().all(|entry| !entry.is_default())
+        && let Some(entry) = entries.first_mut()
+    {
+        entry.mark_default();
     }
 
     // Execute the late phase.
     phase(context.clone(), &config.phases.late).context("unable to execute late phase")?;
 
-    // If --boot is specified, or defaults.entry is specified, use that to find the entry to boot.
-    let boot = context
+    // If --boot is specified, boot that entry immediately.
+    let force_boot_entry = context.root().options().boot.as_ref();
+    // If --force-menu is specified, show the boot menu regardless of the value of --boot.
+    let force_boot_menu = context.root().options().force_menu;
+
+    // Determine the menu timeout in seconds based on the options or configuration.
+    // We prefer the options over the configuration to allow for overriding.
+    let menu_timeout = context
         .root()
         .options()
-        .boot
-        .as_ref()
-        .or(config.defaults.entry.as_ref());
+        .menu_timeout
+        .unwrap_or(config.defaults.menu_timeout);
+    let menu_timeout = Duration::from_secs(menu_timeout);
 
-    // Use the boot option if possible, otherwise pick the first entry.
-    let entry = if let Some(ref boot) = boot {
-        entries
-            .iter()
-            .enumerate()
-            .find(|(index, entry)| {
-                entry.name() == boot.as_str()
-                    || entry.title() == boot.as_str()
-                    || index.to_string() == boot.as_str()
-            })
-            .context(format!("unable to find entry: {boot}"))?
-            .1 // select the bootable entry.
+    // Use the forced boot entry if possible, otherwise pick the first entry using a boot menu.
+    let entry = if !force_boot_menu && let Some(ref force_boot_entry) = force_boot_entry {
+        BootableEntry::find(force_boot_entry, entries.iter())
+            .context(format!("unable to find entry: {force_boot_entry}"))?
     } else {
-        entries.first().context("no entries found")?
+        // Delegate to the menu to select an entry to boot.
+        menu::select(menu_timeout, &entries).context("unable to select entry via boot menu")?
     };
 
     // Execute all the actions for the selected entry.

src/menu.rs

@@ -0,0 +1,153 @@
+use crate::entries::BootableEntry;
+use anyhow::{Context, Result, bail};
+use std::time::Duration;
+use uefi::ResultExt;
+use uefi::boot::TimerTrigger;
+use uefi::proto::console::text::{Input, Key, ScanCode};
+use uefi_raw::table::boot::{EventType, Tpl};
+
+/// The characters that can be used to select an entry from keys.
+const ENTRY_NUMBER_TABLE: &[char] = &['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];
+
+/// Represents the operation that can be performed by the boot menu.
+#[derive(PartialEq, Eq)]
+enum MenuOperation {
+    /// The user selected a numbered entry.
+    Number(usize),
+    /// The user selected the escape key to exit the boot menu.
+    Exit,
+    /// The user selected the enter key to display the entries again.
+    Continue,
+    /// Timeout occurred.
+    Timeout,
+    /// No operation should be performed.
+    Nop,
+}
+
+/// Read a key from the input device with a duration, returning the [MenuOperation] that was
+/// performed.
+fn read(input: &mut Input, timeout: &Duration) -> Result<MenuOperation> {
+    // The event to wait for a key press.
+    let key_event = input
+        .wait_for_key_event()
+        .context("unable to acquire key event")?;
+
+    // Timer event for timeout.
+    // SAFETY: The timer event creation allocated a timer pointer on the UEFI heap.
+    // This is validated safe as long as we are in boot services.
+    let timer_event = unsafe {
+        uefi::boot::create_event_ex(EventType::TIMER, Tpl::CALLBACK, None, None, None)
+            .context("unable to create timer event")?
+    };
+    // The timeout is in increments of 100 nanoseconds.
+    let trigger = TimerTrigger::Relative(timeout.as_nanos() as u64 / 100);
+    uefi::boot::set_timer(&timer_event, trigger).context("unable to set timeout timer")?;
+
+    let mut events = [timer_event, key_event];
+    let event = uefi::boot::wait_for_event(&mut events)
+        .discard_errdata()
+        .context("unable to wait for event")?;
+
+    // The first event is the timer event.
+    // If it has triggered, the user did not select a numbered entry.
+    if event == 0 {
+        return Ok(MenuOperation::Timeout);
+    }
+
+    // If we reach here, there is a key event.
+    let Some(key) = input.read_key().context("unable to read key")? else {
+        bail!("no key was pressed");
+    };
+
+    match key {
+        Key::Printable(c) => {
+            // If the key is not ascii, we can't process it.
+            if !c.is_ascii() {
+                return Ok(MenuOperation::Continue);
+            }
+            // Convert the key to a char.
+            let c: char = c.into();
+            // Find the key pressed in the entry number table or continue.
+            Ok(ENTRY_NUMBER_TABLE
+                .iter()
+                .position(|&x| x == c)
+                .map(MenuOperation::Number)
+                .unwrap_or(MenuOperation::Continue))
+        }
+
+        // The escape key is used to exit the boot menu.
+        Key::Special(ScanCode::ESCAPE) => Ok(MenuOperation::Exit),
+
+        // If the special key is unknown, do nothing.
+        Key::Special(_) => Ok(MenuOperation::Nop),
+    }
+}
+
+/// Selects an entry from the list of entries using the boot menu.
+fn select_with_input<'a>(
+    input: &mut Input,
+    timeout: Duration,
+    entries: &'a [BootableEntry],
+) -> Result<&'a BootableEntry> {
+    loop {
+        // If the timeout is not zero, let's display the boot menu.
+        if !timeout.is_zero() {
+            // Until a pretty menu is available, we just print all the entries.
+            println!("Boot Menu:");
+            for (index, entry) in entries.iter().enumerate() {
+                let title = entry.context().stamp(&entry.declaration().title);
+                println!("  [{}] {} ({})", index, title, entry.name());
+            }
+        }
+
+        // Read from input until a valid operation is selected.
+        let operation = loop {
+            // If the timeout is zero, we can exit immediately because there is nothing to do.
+            if timeout.is_zero() {
+                break MenuOperation::Exit;
+            }
+
+            println!();
+            println!("Select a boot entry using the number keys.");
+            println!("Press Escape to exit and enter to display the entries again.");
+
+            let operation = read(input, &timeout)?;
+            if operation != MenuOperation::Nop {
+                break operation;
+            }
+        };
+
+        match operation {
+            // Entry was selected by number. If the number is invalid, we continue.
+            MenuOperation::Number(index) => {
+                let Some(entry) = entries.get(index) else {
+                    println!("invalid entry number");
+                    continue;
+                };
+                return Ok(entry);
+            }
+
+            // When the user exits the boot menu or a timeout occurs, we should
+            // boot the default entry, if any.
+            MenuOperation::Exit | MenuOperation::Timeout => {
+                return entries
+                    .iter()
+                    .find(|item| item.is_default())
+                    .context("no default entry available");
+            }
+
+            // If the operation is to continue or nop, we can just run the loop again.
+            MenuOperation::Continue | MenuOperation::Nop => {
+                continue;
+            }
+        }
+    }
+}
+
+/// Shows a boot menu to select a bootable entry to boot.
+/// The actual work is done internally in [select_with_input] which is called
+/// within the context of the standard input device.
+pub fn select(timeout: Duration, entries: &[BootableEntry]) -> Result<&BootableEntry> {
+    // Acquire the standard input device and run the boot menu.
+    uefi::system::with_stdin(move |input| select_with_input(input, timeout, entries))
+}

src/options.rs

@@ -15,6 +15,10 @@ pub struct SproutOptions {
     pub config: String,
     /// Entry to boot without showing the boot menu.
     pub boot: Option<String>,
+    /// Force display of the boot menu.
+    pub force_menu: bool,
+    /// The timeout for the boot menu in seconds.
+    pub menu_timeout: Option<u64>,
 }
 
 /// The default Sprout options.
@@ -23,6 +27,8 @@ impl Default for SproutOptions {
         Self {
             config: DEFAULT_CONFIG_PATH.to_string(),
             boot: None,
+            force_menu: false,
+            menu_timeout: None,
         }
     }
 }
@@ -49,6 +55,20 @@ impl OptionsRepresentable for SproutOptions {
                     form: OptionForm::Value,
                 },
             ),
+            (
+                "force-menu",
+                OptionDescription {
+                    description: "Force showing of the boot menu",
+                    form: OptionForm::Flag,
+                },
+            ),
+            (
+                "menu-timeout",
+                OptionDescription {
+                    description: "Boot menu timeout, in seconds",
+                    form: OptionForm::Value,
+                },
+            ),
             (
                 "help",
                 OptionDescription {
@@ -76,6 +96,20 @@ impl OptionsRepresentable for SproutOptions {
                     result.boot = Some(value.context("--boot option requires a value")?);
                 }
 
+                "force-menu" => {
+                    // Force showing of the boot menu.
+                    result.force_menu = true;
+                }
+
+                "menu-timeout" => {
+                    // The timeout for the boot menu in seconds.
+                    let value = value.context("--menu-timeout option requires a value")?;
+                    let value = value
+                        .parse::<u64>()
+                        .context("menu-timeout must be a number")?;
+                    result.menu_timeout = Some(value);
+                }
+
                 _ => bail!("unknown option: --{key}"),
             }
         }