xtask: print environment command

README.md

@@ -67,6 +67,8 @@ x86-specific:
 Building the OS
 ---------------
 
+**NOTE** This project uses `xtask`-style build system. To see help, use `cargo xtask --help`.
+
 Prerequisites:
 
 * Decent CPU and a sizable amount of RAM

xtask/src/env.rs

@@ -1,14 +1,14 @@
-use std::path::PathBuf;
+use std::{io, path::PathBuf};
 
 use clap::ValueEnum;
 
-#[derive(Debug, serde::Deserialize)]
+#[derive(Debug, serde::Deserialize, serde::Serialize)]
 #[serde(default)]
 pub struct ToolchainConfig {
     pub branch: String,
 }
 
-#[derive(Debug, serde::Deserialize)]
+#[derive(Debug, serde::Deserialize, serde::Serialize)]
 #[serde(default)]
 pub struct BuildComponents {
     pub libc: bool,
@@ -16,25 +16,25 @@ pub struct BuildComponents {
     pub libcxx: bool,
 }
 
-#[derive(Debug, Default, serde::Deserialize)]
+#[derive(Debug, Default, serde::Deserialize, serde::Serialize)]
 #[serde(default)]
 pub struct AArch64TargetConfig {
     pub components: BuildComponents,
 }
 
-#[derive(Debug, Default, serde::Deserialize)]
+#[derive(Debug, Default, serde::Deserialize, serde::Serialize)]
 #[serde(default)]
 pub struct X86_64TargetConfig {
     pub components: BuildComponents,
 }
 
-#[derive(Debug, Default, serde::Deserialize)]
+#[derive(Debug, Default, serde::Deserialize, serde::Serialize)]
 #[serde(default)]
 pub struct I686TargetConfig {
     pub components: BuildComponents,
 }
 
-#[derive(Debug, Default, serde::Deserialize)]
+#[derive(Debug, Default, serde::Deserialize, serde::Serialize)]
 #[serde(default)]
 pub struct TargetConfig {
     pub aarch64: AArch64TargetConfig,
@@ -42,7 +42,7 @@ pub struct TargetConfig {
     pub i686: I686TargetConfig,
 }
 
-#[derive(Debug, Default, serde::Deserialize)]
+#[derive(Debug, Default, serde::Deserialize, serde::Serialize)]
 #[serde(default)]
 pub struct XTaskConfig {
     pub toolchain: ToolchainConfig,
@@ -174,6 +174,17 @@ impl BuildEnv {
             llvm_sysroot,
         }
     }
+
+    pub fn dump<W: io::Write>(&self, output: &mut W) {
+        match toml::to_string_pretty(&self.config) {
+            Ok(string) => {
+                writeln!(output, "{string}").ok();
+            }
+            Err(error) => {
+                log::error!("Config serialization error: {error}");
+            }
+        }
+    }
 }
 
 impl XTaskConfig {

xtask/src/main.rs

@@ -1,7 +1,7 @@
 #![deny(warnings)]
 #![feature(exit_status_error)]
 
-use std::{fs, path::PathBuf, process::ExitCode};
+use std::{fs, io::stdout, path::PathBuf, process::ExitCode};
 
 use build::CheckAction;
 use clap::{Parser, Subcommand};
@@ -88,6 +88,8 @@ enum SubArgs {
     Toolchain { branch: Option<String> },
     #[clap(about = "Print the host triple")]
     HostTriple,
+    #[clap(about = "Print information about the build environment and configuration")]
+    Env,
 }
 
 fn run(args: Args) -> Result<(), Error> {
@@ -148,6 +150,20 @@ fn run(args: Args) -> Result<(), Error> {
             println!("{}", env.host_triple);
             Ok(())
         }
+        SubArgs::Env => {
+            println!("---   Build information   ---");
+            println!();
+            match config_path {
+                Some(path) => println!(" * Using {}:", path.display()),
+                None => println!(" * Using default xtask config:"),
+            }
+            println!();
+            env.dump(&mut stdout());
+            qemu::dump_config(&env, &mut stdout());
+            println!("--- End build information ---");
+
+            Ok(())
+        }
     }
 }
 

xtask/src/qemu.rs

@@ -1,4 +1,5 @@
 use std::{
+    io,
     path::{Path, PathBuf},
     process::Command,
 };
@@ -18,7 +19,7 @@ use crate::{
 
 const X86_64_UEFI_PATH: &str = "/usr/share/edk2-ovmf/x64/OVMF_CODE.fd";
 
-#[derive(Debug, serde::Deserialize)]
+#[derive(Debug, serde::Deserialize, serde::Serialize)]
 #[serde(rename_all = "kebab-case", default)]
 struct QemuNetworkConfig {
     enable: bool,
@@ -26,7 +27,7 @@ struct QemuNetworkConfig {
     mac: String,
 }
 
-#[derive(Debug, Default, Clone, Copy, serde::Deserialize)]
+#[derive(Debug, Default, Clone, Copy, serde::Deserialize, serde::Serialize)]
 #[serde(rename_all = "kebab-case")]
 enum QemuDiskInterface {
     #[default]
@@ -34,33 +35,33 @@ enum QemuDiskInterface {
     Ahci,
 }
 
-#[derive(Debug, Default, serde::Deserialize)]
+#[derive(Debug, Default, serde::Deserialize, serde::Serialize)]
 #[serde(rename_all = "kebab-case", default)]
 struct QemuDiskConfig {
     interface: QemuDiskInterface,
 }
 
-#[derive(Debug, serde::Deserialize)]
+#[derive(Debug, serde::Deserialize, serde::Serialize)]
 #[serde(rename_all = "kebab-case", default)]
 struct QemuX86_64MachineConfig {
     enable_kvm: bool,
     memory: usize,
 }
 
-#[derive(Debug, serde::Deserialize)]
+#[derive(Debug, serde::Deserialize, serde::Serialize)]
 #[serde(rename_all = "kebab-case", default)]
 struct QemuAArch64MachineConfig {
     memory: usize,
 }
 
-#[derive(Debug, serde::Deserialize)]
+#[derive(Debug, serde::Deserialize, serde::Serialize)]
 #[serde(rename_all = "kebab-case", default)]
 struct QemuI686MachineConfig {
     enable_kvm: bool,
     memory: usize,
 }
 
-#[derive(Debug, serde::Deserialize)]
+#[derive(Debug, serde::Deserialize, serde::Serialize)]
 #[serde(default)]
 struct QemuMachineConfig {
     x86_64: QemuX86_64MachineConfig,
@@ -69,7 +70,7 @@ struct QemuMachineConfig {
     smp: usize,
 }
 
-#[derive(Debug, Default, serde::Deserialize)]
+#[derive(Debug, Default, serde::Deserialize, serde::Serialize)]
 #[serde(rename_all = "kebab-case", default)]
 struct QemuConfig {
     network: QemuNetworkConfig,
@@ -291,6 +292,23 @@ fn add_devices_from_config(
     Ok(())
 }
 
+pub fn dump_config<W: io::Write>(env: &BuildEnv, output: &mut W) {
+    let config_path = env.workspace_root.join("qemu.toml");
+    if config_path.exists() {
+        writeln!(output, " * Using qemu.toml:").ok();
+    } else {
+        writeln!(output, " * Using default qemu config:").ok();
+    }
+    let config = load_qemu_config(config_path);
+
+    writeln!(output).ok();
+    match config.as_ref().map(toml::to_string_pretty) {
+        Ok(Ok(string)) => writeln!(output, "{string}").ok(),
+        Ok(Err(error)) => writeln!(output, "<Serialization error: {error}>").ok(),
+        Err(error) => writeln!(output, "<Load error: {error}>").ok(),
+    };
+}
+
 pub fn run(
     env: BuildEnv,
     qemu: Option<PathBuf>,