{"record":{"id":"228e2851152ad89e","repo":"astrid-runtime/astrid","slug":"detached-fuse-service-returned-an-invalid-process","errorCode":null,"errorMessage":"detached FUSE service returned an invalid process identity","messagePattern":"detached FUSE service returned an invalid process identity","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"crates/astrid-storage-provider-fuse/src/main.rs","lineNumber":716,"sourceCode":"    .await\n    .context(\"timed out waiting for the FUSE service\")??;\n    if read == 0 {\n        bail!(\"detached FUSE service exited before readiness\");\n    }\n    if line.len() > 64 * 1024 {\n        bail!(\"detached FUSE service exceeded the startup response size\");\n    }\n    match serde_json::from_str(&line)? {\n        ServiceStartup::Ready {\n            mount_id,\n            pid,\n            access,\n        } => {\n            if !control_path.exists() {\n                bail!(\"detached FUSE service did not retain its control endpoint\");\n            }\n            if pid == 0 {\n                bail!(\"detached FUSE service returned an invalid process identity\");\n            }\n            Ok(ControlReady {\n                mount_id,\n                pid,\n                access,\n            })\n        },\n        ServiceStartup::Error { message } => bail!(\"detached FUSE service failed: {message}\"),\n    }\n}\n\n#[derive(Debug)]\nstruct ControlReady {\n    mount_id: StorageMountId,\n    pid: u32,\n    access: StorageProviderAccessV1,\n}\n","sourceCodeStart":698,"sourceCodeEnd":734,"githubUrl":"https://github.com/astrid-runtime/astrid/blob/affd8760f44190dbdfbec23403f4c4b642c33112/crates/astrid-storage-provider-fuse/src/main.rs#L698-L734","documentation":"The parent validates the pid returned in ServiceStartup::Ready; pid == 0 is not a valid OS process identity (pid 0 is the idle/scheduler). If the service reports a zero pid, the handoff contract is broken and the parent cannot supervise or signal the daemon, so it rejects the startup.","triggerScenarios":"The service serializes ServiceStartup::Ready with an uninitialized or placeholder pid — e.g. it reports the pid of a parent it intends to exit, fails std::process::id(), or the struct field defaulted to 0 during construction.","commonSituations":"Custom daemonization code (double-fork) losing track of the real child pid; a service build where pid was never assigned before replying; running under a sandbox/runtime where process introspection returns 0.","solutions":["Fix the service to populate pid with std::process::id() (after any daemonize/fork step) before sending Ready","Log the pid at the service just before sending Ready and compare with the parent's log","If the service double-forks, report the pid of the process that will keep running, not the intermediate one","Check the ServiceStartup serialization: ensure the pid field isn't skipped/defaulted to 0"],"exampleFix":"// before\nlet startup = ServiceStartup::Ready { mount_id, pid: 0, access };\n// after\nlet startup = ServiceStartup::Ready { mount_id, pid: std::process::id(), access };","handlingStrategy":"validation","validationCode":"// Caller-side sanity check on the returned ControlReady\nif ready.pid == 0 {\n    return Err(anyhow!(\"service reported invalid pid\"));\n}\nif !pid_exists(ready.pid) {\n    return Err(anyhow!(\"service pid {} is not a live process\", ready.pid));\n}","typeGuard":"fn valid_pid(ready: &ControlReady) -> bool { ready.pid != 0 }","tryCatchPattern":"let ready = read_service_startup(&mut child, &launch, &control_path).await?;\nif !valid_pid(&ready) {\n    let _ = child.kill().await;\n    return Err(anyhow!(\"detached FUSE service returned pid 0; service build is broken\"));\n}","preventionTips":["Populate pid with std::process::id() after any daemonize/fork step, immediately before sending Ready","Never default or Option::unwrap_or(0) the pid field in ServiceStartup::Ready","If double-forking, report the pid of the final long-lived process","Add a round-trip test asserting the serialized Ready carries a non-zero pid"],"tags":["fuse","process","protocol","validation"],"backgroundTag":"invalid-argument-value","analyzedSha":"affd8760f44190dbdfbec23403f4c4b642c33112","analyzedAt":"2026-09-09T21:28:12.402Z","contentChangedAt":"2026-09-09T21:28:12.402Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}