Big refactor of entire PID1

build.zig

@@ -14,12 +14,6 @@ pub fn build(b: *std.Build) !void {
     const with_loader = b.option(bool, "loader", "With boot loader") orelse true;
     const with_tools = b.option(bool, "tools", "With tools") orelse true;
 
-    const loglevel = b.option(
-        u8,
-        "loglevel",
-        "Log level",
-    ) orelse @intFromEnum(std.log.Level.debug);
-
     const clap = b.dependency("clap", .{});
 
     const linux_headers_translated = b.addTranslateC(.{
@@ -30,9 +24,6 @@ pub fn build(b: *std.Build) !void {
     });
     const linux_headers_module = linux_headers_translated.addModule("linux_headers");
 
-    const tboot_loader_options = b.addOptions();
-    tboot_loader_options.addOption(u8, "loglevel", loglevel);
-
     if (with_loader) {
         const tboot_loader = b.addExecutable(.{
             .name = "tboot-loader",
@@ -41,7 +32,6 @@ pub fn build(b: *std.Build) !void {
             .optimize = tboot_loader_optimize,
             .strip = optimize != std.builtin.OptimizeMode.Debug,
         });
-        tboot_loader.root_module.addOptions("build_options", tboot_loader_options);
         tboot_loader.root_module.addAnonymousImport("test_key", .{
             .root_source_file = b.path("test/keys/tboot/key.der"),
         });
@@ -148,7 +138,6 @@ pub fn build(b: *std.Build) !void {
         .optimize = optimize,
     });
 
-    unit_tests.root_module.addOptions("build_options", tboot_loader_options);
     unit_tests.root_module.addImport("linux_headers", linux_headers_module);
     const test_step = b.step("test", "Run unit tests");
     test_step.dependOn(&b.addRunArtifact(unit_tests).step);

kernel-configs/generic.nix

@@ -51,7 +51,6 @@ in
     IMA_DEFAULT_HASH_SHA256 = yes;
     IMA_KEXEC = yes;
     IMA_MEASURE_ASYMMETRIC_KEYS = yes;
-    INOTIFY_USER = yes;
     INPUT = yes;
     INPUT_KEYBOARD = yes;
     INPUT_MOUSE = unset;

options.nix

@@ -217,7 +217,10 @@ in
     linux.kconfig.CMDLINE = lib.kernel.freeform (
       toString (
         lib.optionals config.video [ "fbcon=logo-count:1" ]
-        ++ [ (if config.debug then "debug" else "quiet") ]
+        ++ [
+          "printk.devkmsg=on"
+          "loglevel=${if config.debug then "8" else "5"}"
+        ]
         ++ map (c: "console=${c}") config.linux.consoles
       )
     );

pkgs/tinyboot/default.nix

@@ -1,5 +1,4 @@
 {
-  debug ? false,
   withLoader ? true,
   withTools ? true,
 
@@ -51,7 +50,6 @@ stdenv.mkDerivation (
     zigBuildFlags = [
       "-Dtarget=${stdenv.hostPlatform.qemuArch}-${stdenv.hostPlatform.parsed.kernel.name}-${zigLibc}"
       "-Ddynamic-linker=${stdenv.cc.bintools.dynamicLinker}"
-      "-Dloglevel=${toString (if debug then 3 else 2)}" # https://github.com/ziglang/zig/blob/084c2cd90f79d5e7edf76b7ddd390adb95a27f0c/lib/std/log.zig#L78
       "-Dloader=${lib.boolToString withLoader}"
       "-Dtools=${lib.boolToString withTools}"
       "--system"

src/autoboot.zig

@@ -0,0 +1,74 @@
+const std = @import("std");
+const posix = std.posix;
+
+const BootLoader = @import("./boot/bootloader.zig");
+const Console = @import("./console.zig");
+
+const Autoboot = @This();
+
+boot_loader: ?*BootLoader = null,
+
+pub fn init() Autoboot {
+    return .{};
+}
+
+pub fn run(
+    self: *Autoboot,
+    boot_loaders: *std.ArrayList(*BootLoader),
+    timerfd: posix.fd_t,
+) !?Console.Event {
+    if (self.boot_loader) |boot_loader| {
+        defer {
+            self.boot_loader = null;
+        }
+
+        std.log.info("autobooting {s}", .{boot_loader.device});
+
+        const entries = try boot_loader.probe();
+
+        for (entries) |entry| {
+            boot_loader.load(entry) catch |err| {
+                std.log.err(
+                    "failed to load entry {s}: {}",
+                    .{ entry.linux, err },
+                );
+                continue;
+            };
+            return .kexec;
+        }
+    } else {
+        if (boot_loaders.items.len == 0) {
+            return error.NoBootloaders;
+        }
+
+        const head = boot_loaders.orderedRemove(0);
+        try boot_loaders.append(head);
+
+        // If we've already tried this boot loader, this means we've gone full
+        // circle back to the first bootloader, so we are done.
+        if (head.boot_attempted) {
+            return error.NoBootloaders;
+        }
+
+        self.boot_loader = head;
+
+        const timeout = try self.boot_loader.?.timeout();
+        if (timeout == 0) {
+            return self.run(boot_loaders, timerfd);
+        } else {
+            try posix.timerfd_settime(timerfd, .{}, &.{
+                // oneshot
+                .it_interval = .{ .tv_sec = 0, .tv_nsec = 0 },
+                // consider settled after N seconds without any new events
+                .it_value = .{ .tv_sec = timeout, .tv_nsec = 0 },
+            }, null);
+
+            std.log.info(
+                "will boot in {} seconds without any user input",
+                .{timeout},
+            );
+        }
+    }
+
+    return null;
+}