deb: cross-compilation, ephemeral contexts, local builds

Multiple changes:
- New contexts (schroot, unshare)
- Cross-building quirks, with ephemeral contexts and repositories management
- Contexts with parents, global context manager, better lifetime handling
- Local building of binary packages
- Pull: pulling dsc files by default
- Many small bugfixes and changes

Co-authored-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Co-committed-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>

src/deb/cross.rs

@@ -0,0 +1,338 @@
+use crate::context;
+use crate::context::{Context, ContextConfig};
+use directories::ProjectDirs;
+use std::collections::HashMap;
+use std::error::Error;
+use std::fs;
+use std::path::{Path, PathBuf};
+use tar::Archive;
+use xz2::read::XzDecoder;
+
+pub struct EphemeralContextGuard {
+    previous_context: String,
+    chroot_path: PathBuf,
+}
+
+impl EphemeralContextGuard {
+    pub fn new(series: &str) -> Result<Self, Box<dyn Error>> {
+        let current_context_name = context::manager().current_name();
+
+        // Create a temporary directory for the chroot
+        let chroot_path_str = context::current().create_temp_dir()?;
+        let chroot_path = PathBuf::from(chroot_path_str);
+
+        log::debug!(
+            "Creating new chroot for {} at {}...",
+            series,
+            chroot_path.display()
+        );
+
+        // Download and extract the chroot tarball
+        Self::download_and_extract_chroot(series, &chroot_path)?;
+
+        // Switch to an ephemeral context to build the package in the chroot
+        context::manager().set_current_ephemeral(Context::new(ContextConfig::Unshare {
+            path: chroot_path.to_string_lossy().to_string(),
+            parent: Some(current_context_name.clone()),
+        }));
+
+        Ok(Self {
+            previous_context: current_context_name,
+            chroot_path,
+        })
+    }
+
+    fn download_and_extract_chroot(
+        series: &str,
+        chroot_path: &PathBuf,
+    ) -> Result<(), Box<dyn Error>> {
+        // Get project directories for caching
+        let proj_dirs = ProjectDirs::from("com", "pkh", "pkh")
+            .ok_or("Could not determine project directories")?;
+        let cache_dir = proj_dirs.cache_dir();
+        fs::create_dir_all(cache_dir)?;
+
+        // Create tarball filename based on series
+        let tarball_filename = format!("{}-buildd.tar.xz", series);
+        let tarball_path = cache_dir.join(&tarball_filename);
+
+        // Download tarball if it doesn't exist
+        if !tarball_path.exists() {
+            log::debug!("Downloading chroot tarball for {}...", series);
+            Self::download_chroot_tarball(series, &tarball_path)?;
+        } else {
+            log::debug!("Using cached chroot tarball for {}", series);
+        }
+
+        // Extract tarball to chroot directory
+        log::debug!("Extracting chroot tarball to {}...", chroot_path.display());
+        Self::extract_tarball(&tarball_path, chroot_path)?;
+
+        Ok(())
+    }
+
+    fn download_chroot_tarball(series: &str, tarball_path: &Path) -> Result<(), Box<dyn Error>> {
+        // Use mmdebstrap to download the tarball to the cache directory
+        let status = context::current()
+            .command("mmdebstrap")
+            .arg("--variant=buildd")
+            .arg("--mode=unshare")
+            .arg("--format=tar")
+            .arg(series)
+            .arg(tarball_path.to_string_lossy().to_string())
+            .status()?;
+
+        if !status.success() {
+            return Err(format!("Failed to download chroot tarball for series {}", series).into());
+        }
+
+        Ok(())
+    }
+
+    fn extract_tarball(
+        tarball_path: &PathBuf,
+        chroot_path: &PathBuf,
+    ) -> Result<(), Box<dyn Error>> {
+        // Create the chroot directory
+        fs::create_dir_all(chroot_path)?;
+
+        // Open the tarball file
+        let tarball_file = std::fs::File::open(tarball_path)?;
+        let xz_decoder = XzDecoder::new(tarball_file);
+        let mut archive = Archive::new(xz_decoder);
+
+        // Extract all files to the chroot directory
+        archive.unpack(chroot_path)?;
+
+        Ok(())
+    }
+}
+
+impl Drop for EphemeralContextGuard {
+    fn drop(&mut self) {
+        log::debug!("Cleaning up ephemeral context...");
+        // Reset to normal context
+        if let Err(e) = context::manager().set_current(&self.previous_context) {
+            log::error!("Failed to restore context {}: {}", self.previous_context, e);
+        }
+
+        // Remove chroot directory
+        // We use the restored context to execute the cleanup command
+        let result = context::current()
+            .command("sudo")
+            .arg("rm")
+            .arg("-rf")
+            .arg(&self.chroot_path)
+            .status();
+
+        match result {
+            Ok(status) => {
+                if !status.success() {
+                    log::error!(
+                        "Failed to remove chroot directory {}",
+                        self.chroot_path.display()
+                    );
+                }
+            }
+            Err(e) => {
+                log::error!(
+                    "Failed to execute cleanup command for {}: {}",
+                    self.chroot_path.display(),
+                    e
+                );
+            }
+        }
+    }
+}
+
+/// Set environment variables for cross-compilation
+pub fn setup_environment(
+    env: &mut HashMap<String, String>,
+    arch: &str,
+) -> Result<(), Box<dyn Error>> {
+    let dpkg_architecture = String::from_utf8(
+        context::current()
+            .command("dpkg-architecture")
+            .arg("-a")
+            .arg(arch)
+            .output()?
+            .stdout,
+    )?;
+    let env_var_regex = regex::Regex::new(r"(?<key>.*)=(?<value>.*)").unwrap();
+    for l in dpkg_architecture.lines() {
+        let capture = env_var_regex.captures(l).unwrap();
+        let key = capture.name("key").unwrap().as_str().to_string();
+        let value = capture.name("value").unwrap().as_str().to_string();
+
+        env.insert(key.clone(), value.clone());
+
+        if key == "DEB_HOST_GNU_TYPE" {
+            env.insert("CROSS_COMPILE".to_string(), format!("{value}-"));
+        }
+    }
+    env.insert("DEB_BUILD_PROFILES".to_string(), "cross".to_string());
+    env.insert("DEB_BUILD_OPTIONS".to_string(), "nocheck".to_string());
+
+    Ok(())
+}
+
+/// Ensure that repositories for target architecture are available
+/// This also handles the 'ports.ubuntu.com' vs 'archive.ubuntu.com' on Ubuntu
+pub fn ensure_repositories(arch: &str, series: &str) -> Result<(), Box<dyn Error>> {
+    let ctx = context::current();
+    let local_arch = crate::get_current_arch();
+
+    // Add target ('host') architecture
+    ctx.command("dpkg")
+        .arg("--add-architecture")
+        .arg(arch)
+        .status()?;
+
+    // Check if we are on Ubuntu
+    let os_release = String::from_utf8(ctx.command("cat").arg("/etc/os-release").output()?.stdout)?;
+    if !os_release.contains("ID=ubuntu") {
+        return Ok(());
+    }
+
+    // Handle DEB822 format (Ubuntu 24.04+)
+    let deb822_path = "/etc/apt/sources.list.d/ubuntu.sources";
+    let has_deb822 = ctx
+        .command("test")
+        .arg("-f")
+        .arg(deb822_path)
+        .status()?
+        .success();
+
+    if has_deb822 {
+        ensure_repositories_deb822(&ctx, arch, &local_arch, series, deb822_path)?;
+    } else {
+        ensure_repositories_legacy(&ctx, arch, &local_arch, series, "/etc/apt/sources.list")?;
+    }
+
+    Ok(())
+}
+
+fn ensure_repositories_deb822(
+    ctx: &context::Context,
+    arch: &str,
+    local_arch: &str,
+    series: &str,
+    deb822_path: &str,
+) -> Result<(), Box<dyn Error>> {
+    // Scope existing to local_arch if not already scoped
+    ctx.command("sed")
+        .arg("-i")
+        .arg(format!("/URIs:.*\\(archive\\|security\\)\\.ubuntu\\.com/ {{ n; /^Architectures:/ ! i Architectures: {} }}", local_arch))
+        .arg(deb822_path)
+        .status()?;
+
+    // Ensure all components are enabled for the primary architecture
+    ctx.command("sed")
+        .arg("-i")
+        .arg("/URIs:.*\\(archive\\|security\\)\\.ubuntu\\.com/,/Components:/ s/^Components:.*/Components: main restricted universe multiverse/")
+        .arg(deb822_path)
+        .status()?;
+
+    // Ensure all suites (pockets) are enabled for the primary architecture
+    // Excluding 'proposed' as it contains unstable software
+    let suites = format!("{series} {series}-updates {series}-backports {series}-security");
+    ctx.command("sed")
+        .arg("-i")
+        .arg(format!(
+            "/URIs:.*\\(archive\\|security\\)\\.ubuntu\\.com/,/Suites:/ s/^Suites:.*/Suites: {}/",
+            suites
+        ))
+        .arg(deb822_path)
+        .status()?;
+
+    // Add ports if not already present
+    let has_ports = ctx
+        .command("grep")
+        .arg("-q")
+        .arg("ports.ubuntu.com")
+        .arg(deb822_path)
+        .status()?
+        .success();
+
+    if !has_ports {
+        let ports_block = format!(
+            "\nTypes: deb\nURIs: http://ports.ubuntu.com/ubuntu-ports\nSuites: {series} {series}-updates {series}-backports {series}-security\nComponents: main restricted universe multiverse\nSigned-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg\nArchitectures: {arch}\n"
+        );
+        ctx.command("sh")
+            .arg("-c")
+            .arg(format!("echo '{}' >> {}", ports_block, deb822_path))
+            .status()?;
+    }
+    Ok(())
+}
+
+fn ensure_repositories_legacy(
+    ctx: &context::Context,
+    arch: &str,
+    local_arch: &str,
+    series: &str,
+    sources_path: &str,
+) -> Result<(), Box<dyn Error>> {
+    // Scope archive.ubuntu.com and security.ubuntu.com to local_arch if not already scoped
+    ctx.command("sed")
+        .arg("-i")
+        .arg(format!(
+            r"/archive.ubuntu.com\|security.ubuntu.com/ {{ /arch=/ ! {{ /^deb \[/ ! s/^deb /deb [arch={}] /; /^deb \[/ s/^deb \[\([^]]*\)\]/deb [arch={} \1]/ }} }}",
+            local_arch, local_arch
+        ))
+        .arg(sources_path)
+        .status()?;
+
+    // Ensure all components (main restricted universe multiverse) are present for all archive/security lines
+    ctx.command("sed")
+        .arg("-i")
+        .arg(r"/archive.ubuntu.com\|security.ubuntu.com/ s/\( main\)\?\([ ]\+restricted\)\?\([ ]\+universe\)\?\([ ]\+multiverse\)\?$/ main restricted universe multiverse/")
+        .arg(sources_path)
+        .status()?;
+
+    // Ensure all pockets exist. If not, we append them.
+    for pocket in ["", "-updates", "-backports", "-security"] {
+        let suite = format!("{}{}", series, pocket);
+        let has_suite = ctx
+            .command("grep")
+            .arg("-q")
+            .arg(format!(" {}", suite))
+            .arg(sources_path)
+            .status()?
+            .success();
+
+        if !has_suite {
+            let line = format!(
+                "deb [arch={}] http://archive.ubuntu.com/ubuntu/ {} main restricted universe multiverse",
+                local_arch, suite
+            );
+            ctx.command("sh")
+                .arg("-c")
+                .arg(format!("echo '{}' >> {}", line, sources_path))
+                .status()?;
+        }
+    }
+
+    // Add ports repository to sources.list if not already present
+    let has_ports = ctx
+        .command("grep")
+        .arg("-q")
+        .arg("ports.ubuntu.com")
+        .arg(sources_path)
+        .status()?
+        .success();
+
+    if !has_ports {
+        let ports_lines = format!(
+            "deb [arch={arch}] http://ports.ubuntu.com/ubuntu-ports {series} main restricted universe multiverse\n\
+             deb [arch={arch}] http://ports.ubuntu.com/ubuntu-ports {series}-updates main restricted universe multiverse\n\
+             deb [arch={arch}] http://ports.ubuntu.com/ubuntu-ports {series}-backports main restricted universe multiverse\n\
+             deb [arch={arch}] http://ports.ubuntu.com/ubuntu-ports {series}-security main restricted universe multiverse"
+        );
+        ctx.command("sh")
+            .arg("-c")
+            .arg(format!("echo '{}' >> {}", ports_lines, sources_path))
+            .status()?;
+    }
+    Ok(())
+}