feat(ci): check-clock-usage — enforce the wall-clock allowlist

.github/workflows/source-gates.yml

@@ -5,7 +5,7 @@ name: Source Gates
 # These ran as seven separate workflows. Each paid ~26s compiling the xtask
 # binary and ~13s compiling its test binary to do a few seconds of file walking,
 # and all seven shared one cache key — so they raced, and six of every seven
-# cache saves were discarded. One job compiles xtask once and runs all eight
+# cache saves were discarded. One job compiles xtask once and runs all nine
 # gates plus the whole fixture suite.
 #
 # `check-all-source-gates` runs every gate before reporting, so one job still

adapters/streamlib-adapter-cuda/Cargo.toml

@@ -62,6 +62,9 @@ serial_test = "3.2"
 # The OPAQUE_FD round-trip tests drive the surface-share daemon directly
 # so they exercise the same wire format helper processes consume.
 serde_json.workspace = true
+# Each test socket gets a directory of its own: the kernel answers uniqueness,
+# and the socket is unlinked on drop instead of littering /tmp.
+tempfile.workspace = true
 
 [[test]]
 name = "conformance"

adapters/streamlib-adapter-cuda/tests/opaque_fd_consumer_rhi_round_trip.rs

@@ -61,21 +61,21 @@ use streamlib_surface_adapter::{
 use streamlib_surface_client::{
     MAX_DMA_BUF_PLANES, connect_to_surface_share_socket, send_request_with_fds,
 };
+use tempfile::TempDir;
 
 const W: u32 = 32;
 const H: u32 = 32;
 const BPP: u32 = 4;
 const SURFACE_ID: &str = "stage6-opaque-fd-round-trip";
 const RUNTIME_ID: &str = "stage6-test-runtime";
 
-fn tmp_socket_path() -> PathBuf {
-    let mut p = std::env::temp_dir();
-    let nanos = std::time::SystemTime::now()
-        .duration_since(std::time::UNIX_EPOCH)
-        .map(|d| d.as_nanos())
-        .unwrap_or(0);
-    p.push(format!("streamlib-stage6-{nanos}.sock"));
-    p
+/// A socket path in a directory of its own, so uniqueness is the kernel's answer.
+/// The returned [`TempDir`] owns that lifetime — dropping it early removes the
+/// socket out from under the running daemon.
+fn tmp_socket_path() -> (TempDir, PathBuf) {
+    let dir = TempDir::new().expect("temp dir for surface-share socket");
+    let path = dir.path().join("stage6.sock");
+    (dir, path)
 }
 
 #[test]
@@ -148,7 +148,7 @@ fn opaque_fd_chain_host_export_to_consumer_import_to_adapter_acquire() {
 
     // ── Phase 2: stand up surface-share daemon ──────────────────────────
     let state = SurfaceShareState::new();
-    let socket_path = tmp_socket_path();
+    let (_socket_dir, socket_path) = tmp_socket_path();
     let mut service = UnixSocketSurfaceService::new(state, socket_path.clone());
     service.start().expect("surface-share service start");
     std::thread::sleep(Duration::from_millis(50));

docs/plan/changes/one-monotonic-clock.md

@@ -125,21 +125,42 @@ Bare patterns — the ship gate greps each line verbatim as a fixed string.
 
 ## ADDED
 
-- ADDED: `cargo xtask check-clock-usage` + its workflow — the mechanical guard that keeps
+- ADDED: `cargo xtask check-clock-usage` ~~+ its workflow~~ — the mechanical guard that keeps
   the wall-clock list from growing by accident. It bans wall-clock reads
-  (`SystemTime::now`, `chrono::Utc::now`, `time.time_ns`, `Date.now`) outside an explicit
+  (`SystemTime::now`, `chrono::Utc::now`, `time.time_ns`, ~~`Date.now`~~) outside an explicit
   file allowlist holding exactly the four surfaces above, in the shape of the existing
   `lint-logging` / `check-no-escalate-in-lifecycle` checks. Recon found a set of
   `SystemTime` uses that mint *unique names*, not timestamps (`vulkan_graphics_kernel.rs:3119`,
   `surface_share/unix_socket_service.rs:977`, several test helpers); those either move to
   a counter/uuid or join the allowlist with a stated reason — final at implementation.
+
+  > Landed 2026-08-12 (#1728). **No workflow** — #1857 consolidated the per-gate workflows,
+  > so the guard is an entry in `ALL_SOURCE_WALKING_GATES` run by the existing `source-gates`
+  > job. **No `Date.now` arm** — the Deno SDK is deleted and the engine tree holds no
+  > `.ts`/`.js` source, so that scan root does not exist; Rust and Python only.
+  >
+  > The unique-name uses are **all converted, none allowlisted** — 16 sites across 15 files.
+  > The allowlist is per-file, so an entry for `iceoryx2/output.rs` or `thread_runner.rs`
+  > would have licensed a wall-clock read in the exact data-plane files the guard exists to
+  > protect. `mint_machine_global_unique_name_suffix()` (`core/machine_global_unique_name.rs`)
+  > is the one primitive, built on the `uuid` the engine already links; the test sockets in
+  > `streamlib-surface-client` and in the cuda adapter's round-trip test take a `TempDir`, the
+  > api-server's name seed takes the OS CSPRNG, and the dead `apple/time.rs::system_time_to_ns`
+  > was deleted. The permitted list holds exactly the four surfaces, as five files
+  > (`host_ts` has two readers).
 - ADDED: an epoch-parity test asserting `MediaClock::now()` and the wheel's
   `monotonic_now_ns` land in the same domain as a directly-read
   `clock_gettime(CLOCK_MONOTONIC)`. The natural home is the existing cross-process gate
   `tests/polyglot_linux_monotonic_clock_parity.rs:112`, which today does **not** include
   `MediaClock` — but its Python/Deno subprocess arms are doomed with the ripout, so the
   surviving shape is host + wheel.
 
+  > Landed as the anticipated host + wheel pair, not one cross-process test: the Rust half is
+  > `core/media_clock.rs::now_lands_in_the_kernel_monotonic_domain` (#1725), which brackets
+  > `MediaClock::now()` between two direct `clock_gettime(CLOCK_MONOTONIC)` reads, and the
+  > Python half is `tests/test_clock_and_log.py::test_monotonic_now_ns_reads_the_kernel_monotonic_clock`.
+  > `polyglot_linux_monotonic_clock_parity.rs` went with the ripout.
+
 ## Notes (not tickets)
 
 - No test anywhere asserts a frame timestamp is small or near zero, so the epoch flip

runtime/streamlib-api-server/processors/api_server.rs

@@ -89,16 +89,21 @@ const NOUNS: &[&str] = &[
 fn generate_runtime_name() -> String {
     use std::collections::hash_map::DefaultHasher;
     use std::hash::{Hash, Hasher};
-    use std::time::{SystemTime, UNIX_EPOCH};
 
-    // Use time + pid for randomness without adding fastrand dependency
-    let seed = SystemTime::now()
-        .duration_since(UNIX_EPOCH)
-        .unwrap()
-        .as_nanos() as u64
-        ^ (std::process::id() as u64);
+    // The OS CSPRNG this crate already links for bearer tokens.
+    let mut seed_bytes = [0u8; 8];
+    if let Err(csprng_unavailable) = getrandom::getrandom(&mut seed_bytes) {
+        // A display name is not worth failing a runtime over, and the pid still
+        // separates concurrent runtimes on one host.
+        tracing::warn!("OS CSPRNG unavailable for runtime naming: {csprng_unavailable}");
+        seed_bytes = (std::process::id() as u64).to_ne_bytes();
+    }
+
+    // The two indices read disjoint halves, so the seed has to be diffused
+    // across all 64 bits first: a pid is well under 2^32, which would otherwise
+    // leave the high half zero and pin every degraded runtime to one noun.
     let mut hasher = DefaultHasher::new();
-    seed.hash(&mut hasher);
+    seed_bytes.hash(&mut hasher);
     let hash = hasher.finish();
 
     let adj = ADJECTIVES[(hash as usize) % ADJECTIVES.len()];

runtime/streamlib-engine/benches/output_writer_ffi_hop.rs

@@ -43,6 +43,7 @@ use std::sync::Arc;
 use criterion::{Criterion, black_box, criterion_group, criterion_main};
 use iceoryx2::prelude::*;
 
+use streamlib_engine::core::machine_global_unique_name::mint_machine_global_unique_name_suffix;
 use streamlib_engine::iceoryx2::{
     ChannelEgressConfig, ChannelTrustTier, OutputWriter, OutputWriterInner,
     TRUSTED_CHANNEL_PAYLOAD_CEILING_BYTES,
@@ -52,13 +53,8 @@ use streamlib_engine::iceoryx2::{
 /// don't collide on iceoryx2's machine-global `/dev/shm` namespace.
 fn unique_suffix(tag: &str) -> String {
     format!(
-        "bench/output_writer/{}/{}/{}",
-        tag,
-        std::process::id(),
-        std::time::SystemTime::now()
-            .duration_since(std::time::UNIX_EPOCH)
-            .unwrap()
-            .as_nanos()
+        "bench/output_writer/{tag}/{}",
+        mint_machine_global_unique_name_suffix()
     )
 }
 

runtime/streamlib-engine/src/apple/time.rs

@@ -5,8 +5,6 @@
 // Review if these high-precision timing functions are needed or can be removed
 #![allow(dead_code)]
 
-use std::time::{SystemTime, UNIX_EPOCH};
-
 #[link(name = "CoreServices", kind = "framework")]
 extern "C" {
     fn mach_absolute_time() -> u64;
@@ -34,10 +32,6 @@ pub fn mach_now_ns() -> i64 {
     }
 }
 
-pub fn system_time_to_ns(time: SystemTime) -> i64 {
-    time.duration_since(UNIX_EPOCH).unwrap().as_nanos() as i64
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -53,11 +47,4 @@ mod tests {
         let elapsed = ns2 - ns1;
         assert!((10_000_000..20_000_000).contains(&elapsed));
     }
-
-    #[test]
-    fn test_system_time_conversion() {
-        let now = SystemTime::now();
-        let ns = system_time_to_ns(now);
-        assert!(ns > 0);
-    }
 }

runtime/streamlib-engine/src/core/compiler/compiler_ops/open_iceoryx2_service_op.rs

@@ -750,6 +750,7 @@ mod tests {
     use super::*;
     use crate::core::execution::ExecutionConfig;
     use crate::core::graph::{InputLinkPortRef, OutputLinkPortRef};
+    use crate::core::machine_global_unique_name::mint_machine_global_unique_name_suffix;
     use crate::core::processors::{DynGeneratedProcessor, PROCESSOR_REGISTRY, ProcessorSpec};
     use crate::core::{ProcessorDescriptor, RuntimeContextFullAccess, RuntimeContextLimitedAccess};
 
@@ -984,13 +985,8 @@ mod tests {
     /// the stale service, not as a clean failure.
     fn unique_service_name(tag: &str) -> String {
         format!(
-            "test/wiring/{}/{}/{}",
-            tag,
-            std::process::id(),
-            std::time::SystemTime::now()
-                .duration_since(std::time::UNIX_EPOCH)
-                .unwrap()
-                .as_nanos()
+            "test/wiring/{tag}/{}",
+            mint_machine_global_unique_name_suffix()
         )
     }
 

runtime/streamlib-engine/src/core/execution/thread_runner.rs

@@ -576,18 +576,14 @@ fn dispatch_on_resume(
 #[cfg(all(test, target_os = "linux"))]
 mod tests {
     use super::*;
+    use crate::core::machine_global_unique_name::mint_machine_global_unique_name_suffix;
     use iceoryx2::prelude::*;
     use std::os::fd::{AsRawFd, FromRawFd};
 
     fn unique_suffix(tag: &str) -> String {
         format!(
-            "test/runner/{}/{}/{}",
-            tag,
-            std::process::id(),
-            std::time::SystemTime::now()
-                .duration_since(std::time::UNIX_EPOCH)
-                .unwrap()
-                .as_nanos()
+            "test/runner/{tag}/{}",
+            mint_machine_global_unique_name_suffix()
         )
     }
 

runtime/streamlib-engine/src/core/logging/event.rs

@@ -79,8 +79,13 @@ pub struct RuntimeLogEvent {
     /// Schema version of this record. Bumped on breaking changes.
     pub schema_version: u32,
 
-    /// Host monotonic receipt timestamp, nanoseconds since UNIX epoch.
+    /// Host receipt wall-clock timestamp, nanoseconds since the UNIX epoch.
     /// Authoritative sort key across the merged stream.
+    ///
+    /// Wall clock, not monotonic: a log record's job is correlating StreamLib
+    /// with the outside world and with other hosts' logs, which monotonic time
+    /// cannot do. Never compare or subtract this against a media timestamp —
+    /// they share a unit and are different quantities.
     pub host_ts: u64,
 
     /// Unique runtime identifier (from [`RuntimeUniqueId`]).

runtime/streamlib-engine/src/core/machine_global_unique_name.rs

@@ -0,0 +1,73 @@
+// Copyright (c) 2025 Jonathan Fontanez
+// SPDX-License-Identifier: BUSL-1.1
+
+//! Unique-name minting for machine-global namespaces.
+//!
+//! iceoryx2 service names live in `/dev/shm`, which is machine-global and
+//! outlives the process that created an entry. A name that collides with a
+//! concurrent process — or with a stale entry an earlier run left behind after
+//! the pid was recycled — surfaces as `DoesNotSupportRequestedMinBufferSize`
+//! against the wrong service, not as a clean failure.
+//!
+//! Nothing minted here is a timestamp. A v4 UUID's 122 random bits make every
+//! mint distinct across processes, across runs and across reboots, so no clock
+//! is read and no counter is kept. The pid prefix is diagnostic: it is what lets
+//! someone reading a stale `/dev/shm` entry or a leftover `/tmp` file name the
+//! process that left it.
+//!
+//! The suffix carries no separator a path or a file name would reject, so the
+//! caller composes it into whatever naming convention its namespace uses.
+
+use uuid::Uuid;
+
+/// A `<pid>-<uuid>` suffix no concurrent process, and no earlier run, can
+/// collide with.
+pub fn mint_machine_global_unique_name_suffix() -> String {
+    format!("{}-{}", std::process::id(), Uuid::new_v4())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::collections::HashSet;
+
+    #[test]
+    fn successive_mints_never_repeat() {
+        let minted: HashSet<String> = (0..10_000)
+            .map(|_| mint_machine_global_unique_name_suffix())
+            .collect();
+        assert_eq!(minted.len(), 10_000, "two mints collided");
+    }
+
+    /// The pid is a fixed prefix within one process, so distinctness can only
+    /// come from the UUID — this fails if that component is ever dropped or
+    /// made constant, which a whole-string equality test does not catch.
+    #[test]
+    fn the_uuid_component_is_what_differs_between_two_mints() {
+        let first = mint_machine_global_unique_name_suffix();
+        let second = mint_machine_global_unique_name_suffix();
+
+        let pid_prefix = format!("{}-", std::process::id());
+        let first_uuid = first.strip_prefix(&pid_prefix).expect(&first);
+        let second_uuid = second.strip_prefix(&pid_prefix).expect(&second);
+
+        assert_ne!(first_uuid, second_uuid);
+        assert!(
+            Uuid::parse_str(first_uuid).is_ok(),
+            "a stale entry stays traceable only while the suffix parses: {first}"
+        );
+    }
+
+    #[test]
+    fn carries_no_separator_a_path_or_file_name_would_reject() {
+        let minted = mint_machine_global_unique_name_suffix();
+        assert!(
+            !minted.contains(['/', '\\', '.', ' ']),
+            "callers compose this into iceoryx2 service paths and into file names: {minted}"
+        );
+        assert!(
+            minted.starts_with(&format!("{}-", std::process::id())),
+            "a stale entry names the process that left it: {minted}"
+        );
+    }
+}

runtime/streamlib-engine/src/core/mod.rs

@@ -33,6 +33,7 @@ pub mod execution;
 pub mod graph;
 pub mod graph_snapshot;
 pub mod json_schema;
+pub mod machine_global_unique_name;
 pub mod media_clock;
 pub mod prelude;
 pub mod processors;

runtime/streamlib-engine/src/core/pubsub/integration_tests.rs

@@ -30,6 +30,7 @@ use super::events::{
     Event, EventListener, KeyCode, KeyState, Modifiers, MouseButton, MouseState, ProcessorEvent,
     RuntimeEvent, topics,
 };
+use crate::core::machine_global_unique_name::mint_machine_global_unique_name_suffix;
 use crate::iceoryx2::{Iceoryx2Node, MAX_EVENT_PAYLOAD_SIZE};
 use parking_lot::Mutex;
 use std::sync::Arc;
@@ -181,7 +182,10 @@ fn test_iceoryx2_direct_delivery() {
     // Bypass PubSub layer entirely — verify iceoryx2 pub/sub works in-process
     let node = Iceoryx2Node::new().expect("Failed to create iceoryx2 node");
 
-    let service_name = format!("streamlib/diag-{}/events/test", uuid::Uuid::new_v4());
+    let service_name = format!(
+        "streamlib/diag-{}/events/test",
+        mint_machine_global_unique_name_suffix()
+    );
 
     // Create subscriber FIRST (must exist before publisher sends)
     let sub_service = node

runtime/streamlib-engine/src/core/runtime/tap.rs

@@ -321,19 +321,15 @@ mod tests {
     use iceoryx2::prelude::*;
     use streamlib_ipc_types::RESERVED_TAP_SUBSCRIBER_SLOTS_PER_CHANNEL;
 
+    use crate::core::machine_global_unique_name::mint_machine_global_unique_name_suffix;
     use crate::iceoryx2::{FRAME_HEADER_SIZE, Iceoryx2Node, Iceoryx2Service};
 
     const RING_DEPTH: usize = 16;
 
     fn unique_channel_name(tag: &str) -> String {
         format!(
-            "test/tap/{}/{}/{}",
-            tag,
-            std::process::id(),
-            std::time::SystemTime::now()
-                .duration_since(std::time::UNIX_EPOCH)
-                .unwrap()
-                .as_nanos()
+            "test/tap/{tag}/{}",
+            mint_machine_global_unique_name_suffix()
         )
     }