[bartlomieju]

Summary

Fixes #33759.

CString::new() in uv_pipe_bind rejected paths containing NUL bytes, but abstract Unix sockets (Linux) require a \0 prefix in sockaddr_un.sun_path. This broke Nuxt 4 / Nitro, which uses \0socketname on Linux with Node >= 20.

Root cause

Nitro's getSocketAddress() on Linux:

if (process.platform === "linux") {
  const nodeMajor = Number.parseInt(process.versions.node.split(".")[0], 10);
  if (nodeMajor >= 20) {
    return `\0${socketName}`;  // Abstract Unix socket
  }
}

In uv_pipe_bind, CString::new(path) returns Err(NulError) for this path → mapped to UV_EINVAL → bind silently fails → uv_pipe_listen finds internal_fd = None → returns UV_EINVAL → surfaces as "listen EINVAL: invalid argument".

Changes

• libs/core/uv_compat/pipe.rs: Extract make_sockaddr_un() helper that builds sockaddr_un correctly for both abstract sockets (raw bytes, no NUL terminator) and filesystem sockets (NUL-terminated, interior NULs rejected). Applied to both uv_pipe_bind and uv_pipe_connect.
• libs/core/uv_compat/pipe.rs (close_pipe): Skip remove_file for abstract sockets (no filesystem entry).
• ext/node/ops/pipe_wrap.rs (fchmod): No-op for abstract sockets (chmod doesn't apply).
• ext/node/polyfills/net.ts: Add readableAll/writableAll validation for abstract socket paths (matching Node.js behavior).
• tests/node_compat/config.jsonc: Enable test-pipe-abstract-socket.js and test-pipe-abstract-socket-http.js.

Test plan

• Verified EINVAL no longer occurs with abstract socket paths (previously reproducible on all platforms)
• Verified filesystem socket paths still work correctly
• Verified readableAll/writableAll throws on abstract socket paths
• Verified Nuxt 4 dev server starts and serves HTTP 200 with the fix
• Enabled two Node.js compat tests (test-pipe-abstract-socket.js, test-pipe-abstract-socket-http.js) — both are Linux-only (self-skip on other platforms)

[fibibot]

LGTM. Real-world Nuxt 4 / Nitro fix — CString::new() was rejecting the leading-NUL paths that Linux uses for abstract Unix sockets. The walkthrough in the PR body (bind → CString::new fails → UV_EINVAL → listen finds internal_fd=None → "listen EINVAL") lines up exactly with what's in the diff.

What I verified

make_sockaddr_un helper (libs/core/uv_compat/pipe.rs:355-407): clean shape that distinguishes the two cases by leading-byte check:

• Abstract: copies bytes directly into sun_path, no NUL terminator. addr_len = sizeof(sa_family_t) + path.len(). ✓ matches Linux's expected layout.
• Filesystem: rejects interior NULs (correct — they'd truncate), NUL-terminates, addr_len = sizeof(sa_family_t) + path.len() + 1. ✓

Both branches check path.len() > sun_path.len() (108 on Linux) for overflow. Empty-path check up front returns UV_EINVAL. Edge cases (single \0, max-length abstract, max-length filesystem) all map correctly.

Applied consistently across the lifecycle:

• uv_pipe_bind (line 431): uses the helper. ✓
• uv_pipe_connect (line 560): uses the helper. ✓
• close_pipe (line 928): is_none_or(|&b| b != 0) correctly skips remove_file for abstract paths (no filesystem entry to clean up). ✓
• pipe_wrap.rs:fchmod (line 449-453): early-returns 0 for abstract paths (chmod not applicable). ✓
• net.ts readableAll/writableAll validation: throws ERR_INVALID_ARG_VALUE when used with abstract paths — matches Node's behavior. ✓

Test coverage: Two Node compat tests enabled (test-pipe-abstract-socket.js, test-pipe-abstract-socket-http.js) — both Linux-only, self-skip on macOS/Windows. The test-pipe-abstract-socket-http.js is the load-bearing one for Nuxt-style use cases (HTTP server over abstract socket).

Non-blocking nit

Minor typo in net.ts error message: "can not set readableAll or writableAllt to true..." — extra t after writableAll. Cosmetic, can land in a follow-up if you want to keep this PR's diff minimal.

CI

135 success, 1 skipping, 0 fail across all platforms × debug + release. The Linux-specific tests pass on Linux shards and skip cleanly on macOS/Windows.