Bind cold start to production authorities

crates/lazaret-host-coordinator/Cargo.toml

@@ -40,5 +40,9 @@ name = "escalation"
 path = "tests/escalation.rs"
 harness = false
 
+[[test]]
+name = "production"
+path = "tests/production.rs"
+
 [lints]
 workspace = true

crates/lazaret-host-coordinator/src/lib.rs

@@ -6,5 +6,6 @@ pub mod domain_store;
 pub mod escalation;
 pub mod lifecycle;
 pub mod network;
+pub mod production;
 pub mod runtime;
 pub mod state_anchor;

crates/lazaret-host-coordinator/src/lifecycle.rs

@@ -282,17 +282,53 @@ where
         generation: Generation,
         session: Session,
     ) -> Result<(), LifecycleError<A::Error>> {
+        self.bootstrap_new_domain_while_owner_live(generation, session, || true)
+            .map(|_| ())
+    }
+
+    /// Drives cold start while checking the bootstrap owner's exact lifetime authority.
+    ///
+    /// Returns `false` after applying the modeled bootstrap-owner disconnect transition.
+    ///
+    /// # Errors
+    /// Returns the first invalid transition, durable update, or production adapter failure.
+    pub fn bootstrap_new_domain_while_owner_live(
+        &mut self,
+        generation: Generation,
+        session: Session,
+        mut owner_live: impl FnMut() -> bool,
+    ) -> Result<bool, LifecycleError<A::Error>> {
+        let session_id = session.session_id;
         self.start_new_domain(generation, session)?;
+        macro_rules! checkpoint {
+            () => {
+                if !owner_live() {
+                    self.disconnect_session(session_id)?;
+                    return Ok(false);
+                }
+            };
+        }
+        checkpoint!();
         self.create_trust_anchor()?;
+        checkpoint!();
         self.start_runtime_supervisor()?;
+        checkpoint!();
         self.lease_prepared_lower()?;
+        checkpoint!();
         self.mount_state_anchor()?;
+        checkpoint!();
         self.start_sidecar()?;
+        checkpoint!();
         self.start_connectivity_helper()?;
+        checkpoint!();
         self.mark_network_ready()?;
+        checkpoint!();
         self.arm_runtime_causal_edge()?;
+        checkpoint!();
         self.start_sandbox()?;
-        self.publish_domain()
+        checkpoint!();
+        self.publish_domain()?;
+        Ok(true)
     }
 
     /// # Errors

crates/lazaret-host-coordinator/src/production.rs

@@ -0,0 +1,445 @@
+use std::ffi::OsString;
+use std::fmt;
+use std::fs::{self, File, OpenOptions};
+use std::io::Write;
+use std::os::fd::{AsFd, OwnedFd};
+use std::os::unix::ffi::OsStringExt;
+use std::os::unix::fs::{FileExt, PermissionsExt};
+use std::path::{Path, PathBuf};
+use std::sync::{Arc, Mutex};
+
+use lazaret_core::configuration::ResolvedDomainConfiguration;
+use lazaret_core::identity::{BundleDigest, ContainerId};
+use lazaret_core::network::{ReachabilityExpectation, derive_ipv4_policy};
+use lazaret_core::records::{
+    Generation, GenerationIdentity, HostProcessOwnershipSlot, IpAddress, PreparedArtifact, Session,
+};
+use lazaret_linux::filesystem::namespace_identity;
+use lazaret_linux::process::ProcessOwnershipContext;
+use lazaret_runtime_supervisor::network::NetworkProbeRequest;
+use lazaret_runtime_supervisor::sandbox::{
+    RootProcess, SandboxBuildRequest, SandboxBundle, build_sandbox_bundle,
+};
+use lazaret_runtime_supervisor::supervision::{RuntimeNetworkLaunch, RuntimeSupervisorLaunch};
+use lazaret_state_anchor::{StateAnchorLaunchAuthority, StateAnchorLayout};
+use lazaret_storage_catalog::Catalog;
+use rustix::event::{PollFd, PollFlags, Timespec, poll};
+use rustix::fs::{FileType, fstat};
+use rustix::io::{FdFlags, fcntl_setfd};
+use sha2::{Digest, Sha256};
+
+use crate::bootstrap::{
+    ProductionBootstrapPlan, ProductionHostCoordinatorLifecycle, production_lifecycle,
+};
+use crate::domain_store::HostCoordinatorDomainStore;
+
+const NETWORK_NAMESPACE_PATH: &str = "/proc/self/ns/net";
+
+#[derive(Debug)]
+pub struct ProductionColdStartError(String);
+
+impl fmt::Display for ProductionColdStartError {
+    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+        formatter.write_str(&self.0)
+    }
+}
+
+impl std::error::Error for ProductionColdStartError {}
+
+fn failure(error: impl fmt::Display) -> ProductionColdStartError {
+    ProductionColdStartError(error.to_string())
+}
+
+pub struct ProductionColdStartInputs<'a> {
+    pub store: Arc<HostCoordinatorDomainStore>,
+    pub catalog: &'a Catalog,
+    pub configuration: &'a ResolvedDomainConfiguration,
+    pub generation: Generation,
+    pub prepared_artifact: &'a PreparedArtifact,
+    pub root_process: RootProcess,
+    pub resolver_addresses: Vec<IpAddress>,
+    pub network_probe: NetworkProbeRequest,
+    pub reachability: ReachabilityExpectation,
+    pub container_id: ContainerId,
+    pub invoking_uid: u32,
+    pub escalation_client: &'a File,
+}
+
+pub struct BootstrapOwnerGuard {
+    descriptor: OwnedFd,
+}
+
+impl BootstrapOwnerGuard {
+    /// Adopts an inherited bootstrap-owner lifetime pipe without PID sampling.
+    ///
+    /// # Errors
+    /// Refuses a descriptor that is not a pipe or cannot be confined to this process.
+    pub fn from_inherited(descriptor: OwnedFd) -> Result<Self, ProductionColdStartError> {
+        let metadata = fstat(&descriptor).map_err(failure)?;
+        if !FileType::from_raw_mode(metadata.st_mode).is_fifo() {
+            return Err(ProductionColdStartError(
+                "bootstrap-owner lifetime descriptor is not a pipe".into(),
+            ));
+        }
+        fcntl_setfd(descriptor.as_fd(), FdFlags::CLOEXEC).map_err(failure)?;
+        Ok(Self { descriptor })
+    }
+
+    fn is_live(&self) -> std::io::Result<bool> {
+        let mut descriptors = [PollFd::new(&self.descriptor, PollFlags::IN)];
+        poll(&mut descriptors, Some(&Timespec::default()))?;
+        Ok(!descriptors[0]
+            .revents()
+            .intersects(PollFlags::IN | PollFlags::HUP | PollFlags::ERR))
+    }
+}
+
+pub struct ProductionColdStart<'a> {
+    store: Arc<HostCoordinatorDomainStore>,
+    catalog: &'a Catalog,
+    configuration: &'a ResolvedDomainConfiguration,
+    generation: Generation,
+    generation_identity: GenerationIdentity,
+    prepared_artifact: &'a PreparedArtifact,
+    state_anchor_layout: StateAnchorLayout<'a>,
+    runtime_launch: Option<RuntimeSupervisorLaunch>,
+    sandbox_bundle: SandboxBundle,
+    network_policy: lazaret_core::network::CanonicalDerivedNetworkPolicy,
+    network_probe: NetworkProbeRequest,
+    reachability: ReachabilityExpectation,
+    container_id: ContainerId,
+    runtime_root: PathBuf,
+    bundle_digest: BundleDigest,
+    invoking_uid: u32,
+    _staging: RuntimeStaging,
+}
+
+impl<'a> ProductionColdStart<'a> {
+    /// Stages one production generation from validated component authorities.
+    ///
+    /// # Errors
+    /// Refuses mismatched generation/configuration/probe inputs, changed host authority, unsafe
+    /// staging paths, or component construction failure.
+    pub fn stage(inputs: ProductionColdStartInputs<'a>) -> Result<Self, ProductionColdStartError> {
+        require_inputs(&inputs)?;
+        let runtime_domain = host_path(
+            inputs
+                .configuration
+                .runtime_domain_root()
+                .canonical_label()
+                .as_bytes(),
+        );
+        let state_anchor_layout = StateAnchorLayout::create(inputs.configuration)
+            .map_err(|error| failure(format!("State Anchor layout: {error}")))?;
+        let staging = RuntimeStaging::create(
+            &runtime_domain,
+            inputs.container_id,
+            inputs.escalation_client,
+        )
+        .map_err(|error| failure(format!("runtime staging: {error}")))?;
+        let expected_network_namespace = namespace_identity(Path::new(NETWORK_NAMESPACE_PATH))
+            .map_err(|error| failure(format!("network namespace: {error}")))?;
+        let sandbox_bundle = build_sandbox_bundle(SandboxBuildRequest {
+            configuration: inputs.configuration,
+            container_id: inputs.container_id,
+            expected_network_namespace,
+            root_process: inputs.root_process,
+            terminal: None,
+        })
+        .map_err(|error| failure(format!("sandbox bundle: {error}")))?;
+        staging
+            .write_bundle(sandbox_bundle.specification_json())
+            .map_err(|error| failure(format!("bundle staging: {error}")))?;
+        let network_policy = derive_ipv4_policy(inputs.configuration, inputs.resolver_addresses)
+            .map_err(|error| failure(format!("network policy: {error}")))?;
+        let ownership = ProcessOwnershipContext {
+            domain_id: inputs.generation.domain_id,
+            generation_id: inputs.generation.generation_id,
+            coordinator_id: inputs.generation.coordinator_id,
+            slot: HostProcessOwnershipSlot::SandboxRuntimeSupervisor,
+        };
+        let state_anchor =
+            StateAnchorLaunchAuthority::capture(&state_anchor_layout, inputs.prepared_artifact)
+                .map_err(|error| failure(format!("State Anchor authority: {error}")))?;
+        let runtime_launch = RuntimeSupervisorLaunch::from_networked_runsc_command(
+            ownership,
+            sandbox_bundle.command(),
+            RuntimeNetworkLaunch {
+                policy: &network_policy,
+                configuration_fingerprint: inputs.generation.configuration_fingerprint,
+                network_sidecar_id: inputs.generation.network_sidecar_id,
+            },
+        )
+        .map_err(|error| failure(format!("Runtime Supervisor launch: {error}")))?
+        .with_state_anchor(state_anchor);
+        let bundle_digest =
+            BundleDigest::new(Sha256::digest(sandbox_bundle.specification_json()).into());
+        let generation_identity = GenerationIdentity {
+            agent_profile: inputs.configuration.selected_profile().to_owned(),
+            domain_id: inputs.generation.domain_id,
+            generation_id: inputs.generation.generation_id,
+            configuration_fingerprint: inputs.generation.configuration_fingerprint,
+            coordinator_id: inputs.generation.coordinator_id,
+            sandbox_id: inputs.generation.sandbox_id,
+        };
+        Ok(Self {
+            store: inputs.store,
+            catalog: inputs.catalog,
+            configuration: inputs.configuration,
+            generation: inputs.generation,
+            generation_identity,
+            prepared_artifact: inputs.prepared_artifact,
+            state_anchor_layout,
+            runtime_launch: Some(runtime_launch),
+            sandbox_bundle,
+            network_policy,
+            network_probe: inputs.network_probe,
+            reachability: inputs.reachability,
+            container_id: inputs.container_id,
+            runtime_root: runtime_domain.join("runsc"),
+            bundle_digest,
+            invoking_uid: inputs.invoking_uid,
+            _staging: staging,
+        })
+    }
+
+    /// Runs cold start and exposes the exact retained lifecycle to one production service loop.
+    ///
+    /// # Errors
+    /// Returns staging, lifecycle, or service-loop failure. The service is single-use.
+    pub fn run<Service>(
+        mut self,
+        bootstrap_owner: Session,
+        owner_guard: &BootstrapOwnerGuard,
+        service: Service,
+    ) -> Result<(), ProductionColdStartError>
+    where
+        Service: FnOnce(
+            &Mutex<ProductionHostCoordinatorLifecycle<'_, '_>>,
+        ) -> Result<(), ProductionColdStartError>,
+    {
+        let store = Arc::clone(&self.store);
+        let generation = self.generation.clone();
+        let plan = self.take_plan()?;
+        let mut lifecycle = production_lifecycle(&store, plan).map_err(failure)?;
+        let published = lifecycle
+            .bootstrap_new_domain_while_owner_live(generation, bootstrap_owner, || {
+                owner_guard.is_live().unwrap_or(false)
+            })
+            .map_err(failure)?;
+        if !published {
+            return Err(ProductionColdStartError(
+                "bootstrap owner disconnected before publication".into(),
+            ));
+        }
+        service(&Mutex::new(lifecycle))
+    }
+
+    fn take_plan(&mut self) -> Result<ProductionBootstrapPlan<'_>, ProductionColdStartError> {
+        Ok(ProductionBootstrapPlan {
+            store: Arc::clone(&self.store),
+            catalog: self.catalog,
+            configuration: self.configuration,
+            generation_identity: self.generation_identity.clone(),
+            prepared_artifact: self.prepared_artifact,
+            state_anchor_layout: &self.state_anchor_layout,
+            runtime_launch: self.runtime_launch.take().ok_or_else(|| {
+                ProductionColdStartError("production cold start was already consumed".into())
+            })?,
+            sandbox_bundle: &self.sandbox_bundle,
+            network_policy: &self.network_policy,
+            network_probe: self.network_probe.clone(),
+            reachability: &self.reachability,
+            container_id: self.container_id,
+            runtime_root: self.runtime_root.clone(),
+            bundle_digest: self.bundle_digest,
+            invoking_uid: self.invoking_uid,
+        })
+    }
+}
+
+fn require_inputs(inputs: &ProductionColdStartInputs<'_>) -> Result<(), ProductionColdStartError> {
+    if inputs.generation.domain_id != inputs.configuration.domain_id()
+        || inputs.generation.configuration_fingerprint
+            != inputs.configuration.configuration_fingerprint()
+        || inputs.network_probe.domain_id != inputs.generation.domain_id
+        || inputs.network_probe.generation_id != inputs.generation.generation_id
+        || inputs.resolver_addresses.is_empty()
+    {
+        return Err(ProductionColdStartError(
+            "production cold-start inputs disagree".into(),
+        ));
+    }
+    Ok(())
+}
+
+struct RuntimeStaging {
+    bundle: PathBuf,
+    control: PathBuf,
+}
+
+impl RuntimeStaging {
+    fn create(
+        runtime_domain: &Path,
+        container_id: ContainerId,
+        escalation_client: &File,
+    ) -> Result<Self, ProductionColdStartError> {
+        let name = hex(container_id.as_bytes());
+        let bundles = runtime_domain.join("bundles");
+        let controls = runtime_domain.join("sandbox-control");
+        let runsc = runtime_domain.join("runsc");
+        for directory in [&bundles, &controls, &runsc] {
+            ensure_directory(directory)
+                .map_err(|error| failure(format!("creating {}: {error}", directory.display())))?;
+        }
+        let bundle = bundles.join(&name);
+        let control = controls.join(name);
+        fs::create_dir(&bundle)
+            .map_err(|error| failure(format!("creating bundle leaf: {error}")))?;
+        set_private_directory(&bundle)?;
+        if let Err(error) = fs::create_dir(&control) {
+            let _ = fs::remove_dir(&bundle);
+            return Err(failure(error));
+        }
+        if let Err(error) = set_private_directory(&control) {
+            let _ = fs::remove_dir(&control);
+            let _ = fs::remove_dir(&bundle);
+            return Err(error);
+        }
+        let staging = Self { bundle, control };
+        staging.populate_control(escalation_client)?;
+        Ok(staging)
+    }
+
+    fn populate_control(&self, escalation_client: &File) -> Result<(), ProductionColdStartError> {
+        for relative in [
+            "credentials",
+            "mailbox",
+            "mailbox/requests",
+            "mailbox/results",
+            "bin",
+        ] {
+            let directory = self.control.join(relative);
+            fs::create_dir(&directory)
+                .map_err(|error| failure(format!("creating control {relative}: {error}")))?;
+            set_private_directory(&directory)?;
+        }
+        let source = escalation_client
+            .metadata()
+            .map_err(|error| failure(format!("inspecting escalation client: {error}")))?;
+        if !source.file_type().is_file() || source.permissions().mode() & 0o111 == 0 {
+            return Err(ProductionColdStartError(
+                "escalation client is not an executable regular file".into(),
+            ));
+        }
+        copy_descriptor(
+            escalation_client,
+            &self.control.join("bin/lazaret-escalate"),
+        )?;
+        Ok(())
+    }
+
+    fn write_bundle(&self, bytes: &[u8]) -> Result<(), ProductionColdStartError> {
+        let path = self.bundle.join("config.json");
+        let mut file = OpenOptions::new()
+            .write(true)
+            .create_new(true)
+            .open(path)
+            .map_err(failure)?;
+        file.write_all(bytes).map_err(failure)?;
+        file.set_permissions(fs::Permissions::from_mode(0o600))
+            .map_err(failure)?;
+        file.sync_all().map_err(failure)?;
+        Ok(())
+    }
+}
+
+fn copy_descriptor(source: &File, destination: &Path) -> Result<(), ProductionColdStartError> {
+    let mut destination = OpenOptions::new()
+        .write(true)
+        .create_new(true)
+        .open(destination)
+        .map_err(failure)?;
+    destination
+        .set_permissions(fs::Permissions::from_mode(0o700))
+        .map_err(failure)?;
+    let mut offset = 0_u64;
+    let mut buffer = [0_u8; 16 * 1024];
+    loop {
+        let read = source.read_at(&mut buffer, offset).map_err(failure)?;
+        if read == 0 {
+            break;
+        }
+        destination.write_all(&buffer[..read]).map_err(failure)?;
+        offset = offset
+            .checked_add(read as u64)
+            .ok_or_else(|| ProductionColdStartError("escalation client is too large".into()))?;
+    }
+    destination.sync_all().map_err(failure)
+}
+
+fn set_private_directory(path: &Path) -> Result<(), ProductionColdStartError> {
+    fs::set_permissions(path, fs::Permissions::from_mode(0o700)).map_err(failure)
+}
+
+impl Drop for RuntimeStaging {
+    fn drop(&mut self) {
+        let _ = fs::remove_dir_all(&self.control);
+        let _ = fs::remove_dir_all(&self.bundle);
+    }
+}
+
+fn ensure_directory(path: &Path) -> Result<(), ProductionColdStartError> {
+    match fs::create_dir(path) {
+        Ok(()) => Ok(()),
+        Err(error) if error.kind() == std::io::ErrorKind::AlreadyExists => {
+            let metadata = fs::symlink_metadata(path).map_err(failure)?;
+            if metadata.file_type().is_dir() {
+                Ok(())
+            } else {
+                Err(ProductionColdStartError(
+                    "production staging path is not a directory".into(),
+                ))
+            }
+        }
+        Err(error) => Err(failure(error)),
+    }
+}
+
+fn host_path(bytes: &[u8]) -> PathBuf {
+    PathBuf::from(OsString::from_vec(bytes.to_vec()))
+}
+
+fn hex(bytes: &[u8]) -> String {
+    use std::fmt::Write as _;
+
+    bytes.iter().fold(String::new(), |mut output, byte| {
+        write!(output, "{byte:02x}").expect("writing to a String cannot fail");
+        output
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use std::fs::File;
+    use std::os::fd::OwnedFd;
+
+    use rustix::pipe::{PipeFlags, pipe_with};
+
+    use super::BootstrapOwnerGuard;
+
+    #[test]
+    fn bootstrap_owner_guard_tracks_the_exact_inherited_pipe() {
+        let (reader, writer) = pipe_with(PipeFlags::CLOEXEC).unwrap();
+        let guard = BootstrapOwnerGuard::from_inherited(reader).unwrap();
+        assert!(guard.is_live().unwrap());
+        drop(writer);
+        assert!(!guard.is_live().unwrap());
+    }
+
+    #[test]
+    fn bootstrap_owner_guard_refuses_non_pipe_authority() {
+        let descriptor: OwnedFd = File::open("/dev/null").unwrap().into();
+        assert!(BootstrapOwnerGuard::from_inherited(descriptor).is_err());
+    }
+}

crates/lazaret-host-coordinator/tests/lifecycle.rs

@@ -1,3 +1,4 @@
+use std::cell::Cell;
 use std::fs::OpenOptions;
 use std::sync::{Arc, Mutex};
 
@@ -225,6 +226,36 @@ fn complete_startup(
     lifecycle.publish_domain().unwrap();
 }
 
+#[test]
+fn bootstrap_owner_guard_failure_uses_exact_modeled_disconnect_transition() {
+    let directory = tempfile::tempdir().unwrap();
+    let store = open_store(&directory);
+    let (domain_adapter, session_adapter) = adapters();
+    let actions = Arc::clone(&domain_adapter.actions);
+    let mut lifecycle = HostCoordinatorLifecycle::new(&store, domain_adapter, session_adapter);
+    let checks = Cell::new(0_u8);
+    let owner = session(10, 1);
+    let published = lifecycle
+        .bootstrap_new_domain_while_owner_live(generation(1), owner.clone(), || {
+            checks.set(checks.get() + 1);
+            checks.get() < 3
+        })
+        .unwrap();
+    assert!(!published);
+    assert_eq!(lifecycle.phase(), DomainPhase::Failed);
+    assert!(!lifecycle.is_published());
+    assert_eq!(
+        lifecycle.session_phase(owner.session_id),
+        Some(SessionPhase::Closed)
+    );
+    assert!(
+        !actions
+            .lock()
+            .unwrap()
+            .contains(&LifecycleAction::PublishDomain)
+    );
+}
+
 #[test]
 fn exact_start_join_disconnect_and_teardown_actions_are_ordered() {
     let directory = tempfile::tempdir().unwrap();

crates/lazaret-host-coordinator/tests/production.rs

@@ -0,0 +1,185 @@
+use std::collections::BTreeMap;
+use std::fs::{self, File, OpenOptions};
+use std::os::unix::ffi::{OsStrExt, OsStringExt};
+use std::os::unix::fs::{MetadataExt, PermissionsExt};
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+use lazaret_core::configuration::{ConfigurationLoadRequest, load_trusted_configuration};
+use lazaret_core::identity::{
+    ContainerId, CoordinatorId, DeviceId, GenerationId, HostPath, IdMapDigest, InodeId, PolicyId,
+    PreparedArtifactId, SandboxId, SelectedManifestDigest, SourceIdentity,
+};
+use lazaret_core::records::{
+    ArtifactState, Domain, DurableDecision, Generation, IpAddress, PreparedArtifact,
+};
+use lazaret_host_coordinator::domain_store::HostCoordinatorDomainStore;
+use lazaret_host_coordinator::production::{ProductionColdStart, ProductionColdStartInputs};
+use lazaret_linux::filesystem::{namespace_identity, try_exclusive_flock};
+use lazaret_runtime_supervisor::network::NetworkProbeRequest;
+use lazaret_runtime_supervisor::sandbox::{RootProcess, production_sandbox_layout};
+use lazaret_storage_catalog::Catalog;
+use rustix::process::getuid;
+
+#[test]
+fn validated_inputs_stage_one_complete_plan_and_drop_exact_runtime_artifacts() {
+    let tree = tempfile::tempdir().unwrap();
+    let configuration = configuration(tree.path());
+    let persistent_domain = host_path(
+        configuration
+            .persistent_domain_root()
+            .canonical_label()
+            .as_bytes(),
+    );
+    let runtime_domain = host_path(
+        configuration
+            .runtime_domain_root()
+            .canonical_label()
+            .as_bytes(),
+    );
+    let catalog = Catalog::new(
+        tree.path().join("catalog.redb"),
+        tree.path().join("catalog.lock"),
+    );
+    catalog.initialize().unwrap();
+    let domain = Domain {
+        domain_id: configuration.domain_id(),
+        profile_name: configuration.selected_profile().to_owned(),
+        canonical_workspace: configuration.workspace().canonical_label().clone(),
+    };
+    let lock = OpenOptions::new()
+        .read(true)
+        .write(true)
+        .create_new(true)
+        .open(persistent_domain.join("domain.lock"))
+        .unwrap();
+    let store = Arc::new(
+        HostCoordinatorDomainStore::open(
+            try_exclusive_flock(lock).unwrap(),
+            &persistent_domain.join("domain.redb"),
+            &domain,
+        )
+        .unwrap(),
+    );
+    let lower = tree.path().join("prepared-lower");
+    fs::create_dir(&lower).unwrap();
+    let metadata = lower.metadata().unwrap();
+    let artifact = PreparedArtifact {
+        prepared_artifact_id: PreparedArtifactId::new([8; 32]),
+        source_identity: SourceIdentity::new(b"synthetic-spike".to_vec()),
+        selected_manifest_digest: SelectedManifestDigest::new([9; 32]),
+        policy_id: PolicyId::new([10; 32]),
+        id_map_digest: IdMapDigest::new([11; 32]),
+        path: HostPath::new(lower.as_os_str().as_bytes().to_vec()),
+        device: DeviceId::new(metadata.dev()),
+        inode: InodeId::new(metadata.ino()),
+        state: ArtifactState::Available,
+    };
+    let generation = Generation {
+        domain_id: configuration.domain_id(),
+        generation_id: GenerationId::new(1),
+        configuration_fingerprint: configuration.configuration_fingerprint(),
+        coordinator_id: CoordinatorId::new([2; 32]),
+        network_sidecar_id: lazaret_core::identity::NetworkSidecarId::new([3; 32]),
+        sandbox_id: SandboxId::new([4; 32]),
+        durable_decision: DurableDecision::None,
+    };
+    let container_id = ContainerId::new([5; 32]);
+    let escalation_client = File::open("/bin/true").unwrap();
+    let invalid_escalation_client = File::open("/dev/null").unwrap();
+    let inputs = |escalation_client| ProductionColdStartInputs {
+        store: Arc::clone(&store),
+        catalog: &catalog,
+        configuration: &configuration,
+        generation: generation.clone(),
+        prepared_artifact: &artifact,
+        root_process: RootProcess::new("/bin/sh", ["-c".into(), "sleep infinity".into()]).unwrap(),
+        resolver_addresses: vec![IpAddress::V4([10, 0, 2, 3])],
+        network_probe: NetworkProbeRequest {
+            domain_id: configuration.domain_id(),
+            generation_id: GenerationId::new(1),
+            enforcement_namespace: namespace_identity(Path::new("/proc/self/ns/net")).unwrap(),
+            denied: Vec::new(),
+            permitted: Vec::new(),
+            dns: Vec::new(),
+        },
+        reachability: lazaret_core::network::ReachabilityExpectation {
+            denied_destinations: Vec::new(),
+            permitted_destinations: Vec::new(),
+            dns_queries: Vec::new(),
+        },
+        container_id,
+        invoking_uid: getuid().as_raw(),
+        escalation_client,
+    };
+    let staged = ProductionColdStart::stage(inputs(&escalation_client)).unwrap();
+    let name = hex(container_id.as_bytes());
+    let bundle = runtime_domain.join("bundles").join(&name);
+    let control = runtime_domain.join("sandbox-control").join(&name);
+    assert_private_artifacts(&bundle, &control);
+    drop(staged);
+    assert!(!bundle.exists());
+    assert!(!control.exists());
+    assert!(ProductionColdStart::stage(inputs(&invalid_escalation_client)).is_err());
+    assert!(!bundle.exists());
+    assert!(!control.exists());
+}
+
+fn assert_private_artifacts(bundle: &Path, control: &Path) {
+    let config = bundle.join("config.json");
+    let escalation_client = control.join("bin/lazaret-escalate");
+    assert!(config.is_file());
+    assert!(escalation_client.is_file());
+    assert!(control.join("credentials").is_dir());
+    assert_eq!(mode(bundle), 0o700);
+    assert_eq!(mode(control), 0o700);
+    assert_eq!(mode(&config), 0o600);
+    assert_eq!(mode(&escalation_client), 0o700);
+}
+
+fn mode(path: &Path) -> u32 {
+    path.metadata().unwrap().permissions().mode() & 0o777
+}
+
+fn configuration(root: &Path) -> lazaret_core::configuration::ResolvedDomainConfiguration {
+    let configuration_directory = root.join("configuration");
+    let workspace = root.join("workspace");
+    let runtime = root.join("runtime");
+    fs::create_dir(&configuration_directory).unwrap();
+    fs::create_dir(&workspace).unwrap();
+    fs::create_dir(&runtime).unwrap();
+    let configuration_path = configuration_directory.join("lazaret.toml");
+    fs::write(
+        &configuration_path,
+        format!(
+            "schema = \"lazaret-trusted-host-config-v1\"\n\n[storage]\ndata_root = \"{}\"\n\n[profiles.default]\nimage = \"example.invalid/factory:v1\"\npersistent_dirs = []\n",
+            root.join("data").display()
+        ),
+    )
+    .unwrap();
+    load_trusted_configuration(ConfigurationLoadRequest {
+        explicit_configuration_path: Some(configuration_path),
+        selected_profile: "default".into(),
+        workspace,
+        home: root.join("home"),
+        xdg_config_home: None,
+        xdg_data_home: None,
+        xdg_runtime_dir: runtime,
+        environment: BTreeMap::new(),
+        sandbox_layout: production_sandbox_layout().unwrap(),
+    })
+    .unwrap()
+}
+
+fn host_path(bytes: &[u8]) -> PathBuf {
+    PathBuf::from(std::ffi::OsString::from_vec(bytes.to_vec()))
+}
+
+fn hex(bytes: &[u8]) -> String {
+    use std::fmt::Write as _;
+
+    bytes.iter().fold(String::new(), |mut output, byte| {
+        write!(output, "{byte:02x}").unwrap();
+        output
+    })
+}

crates/lazaret-linux/src/process.rs

@@ -328,6 +328,40 @@ impl ChildBroker {
         }
     }
 
+    /// Starts a non-durable direct child with split captured output and exact retained authority.
+    ///
+    /// # Errors
+    /// Refuses invalid parent-edge or SIGCHLD state and cleans up on spawn, pidfd, barrier, or
+    /// pipe-acquisition failure.
+    #[allow(clippy::disallowed_methods, clippy::disallowed_types)]
+    pub fn run_transient_captured(&self, target: &TargetCommand) -> io::Result<CapturedProcess> {
+        let _guard = self
+            .exclusion
+            .lock()
+            .map_err(|_| io::Error::other("child broker lock poisoned"))?;
+        require_captured_parent_edge(target.parent_edge())?;
+        require_default_sigchld()?;
+        require_reapable_sigchld()?;
+        let parent = current_process_identity()?;
+        let (release, wait) = launch_barrier()?;
+        let mut command = private_role_command(WRAPPER_ROLE);
+        append_parent_identity(&mut command, parent);
+        target.append_to(&mut command);
+        command
+            .stdin(wait.into_stdio())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::piped());
+        let mut child = command.spawn()?;
+        let process = match acquire_spawned_child(child.id()) {
+            Ok(process) => process,
+            Err(error) => return fail_before_pidfd(release, &mut child, error),
+        };
+        if let Err(error) = release.release() {
+            return fail_after_pidfd_closed(process, error);
+        }
+        captured_process(process, child)
+    }
+
     /// Spawns the repository wrapper, stages exact ownership, accepts its acknowledgment,
     /// and only then releases target execution.
     ///
@@ -530,6 +564,41 @@ impl ChildBroker {
         if let Err(error) = release.release() {
             return fail_after_pidfd_closed(process, error);
         }
+        captured_process(process, child)
+    }
+
+    /// # Errors
+    /// Returns an error when serialization or exact pidfd reaping fails.
+    #[allow(clippy::disallowed_methods)]
+    pub fn reap(&self, process: RetainedProcess) -> io::Result<()> {
+        self.reap_status(process).map(|_| ())
+    }
+
+    /// # Errors
+    /// Returns an error when serialization or exact pidfd reaping fails.
+    #[allow(clippy::disallowed_methods)]
+    pub fn reap_status(&self, process: RetainedProcess) -> io::Result<ProcessExit> {
+        let _guard = self
+            .exclusion
+            .lock()
+            .map_err(|_| io::Error::other("child broker lock poisoned"))?;
+        let status =
+            rustix::process::waitid(WaitId::PidFd(process.pidfd.as_fd()), WaitIdOptions::EXITED)?
+                .ok_or_else(|| io::Error::other("exact child exited without wait status"))?;
+        let exit = ProcessExit {
+            exit_code: status.exit_status(),
+            terminating_signal: status.terminating_signal(),
+        };
+        drop(process);
+        Ok(exit)
+    }
+}
+
+#[allow(clippy::disallowed_types)]
+fn captured_process(
+    process: RetainedProcess,
+    mut child: std::process::Child,
+) -> io::Result<CapturedProcess> {
     let Some(stdout) = child.stdout.take() else {
         return fail_running_captured(
             process,
@@ -560,33 +629,6 @@ impl ChildBroker {
     })
 }
 
-    /// # Errors
-    /// Returns an error when serialization or exact pidfd reaping fails.
-    #[allow(clippy::disallowed_methods)]
-    pub fn reap(&self, process: RetainedProcess) -> io::Result<()> {
-        self.reap_status(process).map(|_| ())
-    }
-
-    /// # Errors
-    /// Returns an error when serialization or exact pidfd reaping fails.
-    #[allow(clippy::disallowed_methods)]
-    pub fn reap_status(&self, process: RetainedProcess) -> io::Result<ProcessExit> {
-        let _guard = self
-            .exclusion
-            .lock()
-            .map_err(|_| io::Error::other("child broker lock poisoned"))?;
-        let status =
-            rustix::process::waitid(WaitId::PidFd(process.pidfd.as_fd()), WaitIdOptions::EXITED)?
-                .ok_or_else(|| io::Error::other("exact child exited without wait status"))?;
-        let exit = ProcessExit {
-            exit_code: status.exit_status(),
-            terminating_signal: status.terminating_signal(),
-        };
-        drop(process);
-        Ok(exit)
-    }
-}
-
 fn child_pipe_file(fd: OwnedFd) -> io::Result<File> {
     let flags = fcntl_getfl(fd.as_fd())?;
     fcntl_setfl(fd.as_fd(), flags | OFlags::NONBLOCK)?;

crates/lazaret-linux/tests/acquisition.rs

@@ -1,6 +1,6 @@
 use std::ffi::OsString;
 use std::fs::File;
-use std::io::{Seek, Write};
+use std::io::{Read, Seek, Write};
 use std::os::fd::AsFd;
 use std::process::{ExitCode, Stdio};
 use std::sync::atomic::{AtomicU64, AtomicUsize, Ordering};
@@ -45,6 +45,7 @@ fn exit(result: std::io::Result<()>) -> ExitCode {
 
 fn run_all() -> std::io::Result<()> {
     successful_acquisition()?;
+    transient_captured_child_preserves_streams_and_exit()?;
     acknowledged_transition_precedes_exact_wrapper_release()?;
     failed_acknowledged_transition_refuses_exact_wrapper_release()?;
     lifetime_pipe_descriptor_contract()?;
@@ -56,6 +57,47 @@ fn run_all() -> std::io::Result<()> {
     concurrent_acquisitions_serialize()
 }
 
+fn transient_captured_child_preserves_streams_and_exit() -> std::io::Result<()> {
+    let target = TargetCommand::new("/bin/sh")
+        .argument("-c")
+        .argument("printf transient-out; printf transient-err >&2; exit 7");
+    let mut child = child_broker().run_transient_captured(&target)?;
+    let mut stdout = Vec::new();
+    let mut stderr = Vec::new();
+    loop {
+        let (out, err) = child.streams();
+        let out_done = read_available(out, &mut stdout)?;
+        let err_done = read_available(err, &mut stderr)?;
+        if out_done && err_done && child.process().has_exited()? {
+            break;
+        }
+        std::thread::yield_now();
+    }
+    let exit = child_broker().reap_status(child.into_process())?;
+    if stdout != b"transient-out"
+        || stderr != b"transient-err"
+        || exit.exit_code != Some(7)
+        || exit.terminating_signal.is_some()
+    {
+        return Err(std::io::Error::other(
+            "transient captured child changed streams or exit",
+        ));
+    }
+    Ok(())
+}
+
+fn read_available(file: &mut File, output: &mut Vec<u8>) -> std::io::Result<bool> {
+    let mut buffer = [0; 4096];
+    loop {
+        match file.read(&mut buffer) {
+            Ok(0) => return Ok(true),
+            Ok(length) => output.extend_from_slice(&buffer[..length]),
+            Err(error) if error.kind() == std::io::ErrorKind::WouldBlock => return Ok(false),
+            Err(error) => return Err(error),
+        }
+    }
+}
+
 #[allow(clippy::disallowed_methods, clippy::disallowed_types)]
 fn failed_acknowledged_transition_refuses_exact_wrapper_release() -> std::io::Result<()> {
     let target_marker = marker("failed-transition-target");