golang.org/x/sys v0.40.0: unix.Timeval

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify golang.org/x/sys/unix.Timeval in pkg:golang/golang.org/x/sys@v0.40.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/sys@v0.40.0
Demonstrate these symbols/APIs:
  - golang.org/x/sys/unix.Timeval

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:7bde5f4d6be52aac347983ed7aa66f2bb1c12dabfc9ab5e68302e8d945880d99","contract":["unix.Timeval stores seconds (Sec) and microseconds (Usec)","unix.NsecToTimeval converts nanoseconds to unix.Timeval","unix.TimevalToNsec converts unix.Timeval to nanoseconds","Timeval.Nano returns nanoseconds as int64","Timeval.Unix returns seconds and nanoseconds","unix.Gettimeofday populates unix.Timeval with current timestamp","SetsockoptTimeval and GetsockoptTimeval configure socket timeouts with unix.Timeval"],"goal":"verify golang.org/x/sys/unix.Timeval in pkg:golang/golang.org/x/sys@v0.40.0","kind":"HOW","packages":["pkg:golang/golang.org/x/sys@v0.40.0"],"schemaVersion":1,"symbols":["golang.org/x/sys/unix.Timeval"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/sys@v0.40.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/sys@v0.40.0","symbols":["golang.org/x/sys/unix.Timeval"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require golang.org/x/sys v0.40.0

golang.org/x/sys v0.40.0 h1:DBZZqJ2Rkml6QMQsZywtnjnnGvHza6BTfYFWY9kjEWQ=
golang.org/x/sys v0.40.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/sys/unix.Timeval in pkg:golang/golang.org/x/sys@v0.40.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/sys@v0.40.0"
  ],
  "symbols": [
    "golang.org/x/sys/unix.Timeval"
  ]
}

package main

import (
	"fmt"
	"os"
	"time"

	"example.com/sample"
	"golang.org/x/sys/unix"
)

func main() {
	// 1. Verify Timeval struct fields
	tv := unix.Timeval{
		Sec:  12345,
		Usec: 67890,
	}
	if tv.Sec != 12345 || tv.Usec != 67890 {
		fmt.Fprintf(os.Stderr, "Assertion failed: Timeval field values mismatch: got Sec=%d, Usec=%d\n", tv.Sec, tv.Usec)
		os.Exit(1)
	}

	// 2. Verify NsecToTimeval conversion
	nsecInput := int64(5*1_000_000_000 + 250_000_000) // 5.25 seconds
	tvConverted := unix.NsecToTimeval(nsecInput)
	if tvConverted.Sec != 5 || tvConverted.Usec != 250_000 {
		fmt.Fprintf(os.Stderr, "Assertion failed: NsecToTimeval mismatch: got Sec=%d, Usec=%d\n", tvConverted.Sec, tvConverted.Usec)
		os.Exit(1)
	}

	// 3. Verify TimevalToNsec conversion
	nsecOutput := unix.TimevalToNsec(tvConverted)
	if nsecOutput != nsecInput {
		fmt.Fprintf(os.Stderr, "Assertion failed: TimevalToNsec mismatch: got %d, expected %d\n", nsecOutput, nsecInput)
		os.Exit(1)
	}

	// 4. Verify Timeval.Nano method
	if tvConverted.Nano() != nsecInput {
		fmt.Fprintf(os.Stderr, "Assertion failed: Timeval.Nano mismatch: got %d, expected %d\n", tvConverted.Nano(), nsecInput)
		os.Exit(1)
	}

	// 5. Verify Timeval.Unix method
	sec, nsec := tvConverted.Unix()
	if sec != 5 || nsec != 250_000_000 {
		fmt.Fprintf(os.Stderr, "Assertion failed: Timeval.Unix mismatch: got sec=%d, nsec=%d\n", sec, nsec)
		os.Exit(1)
	}

	// 6. Verify Gettimeofday with Timeval
	currentTv, err := sample.GetCurrentTimeval()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Assertion failed: Gettimeofday failed: %v\n", err)
		os.Exit(1)
	}
	if currentTv.Sec <= 0 || currentTv.Usec < 0 || currentTv.Usec >= 1_000_000 {
		fmt.Fprintf(os.Stderr, "Assertion failed: Gettimeofday returned invalid Timeval: Sec=%d, Usec=%d\n", currentTv.Sec, currentTv.Usec)
		os.Exit(1)
	}

	// 7. Verify SetsockoptTimeval and GetsockoptTimeval
	socketFd, err := unix.Socket(unix.AF_UNIX, unix.SOCK_STREAM, 0)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Assertion failed: unix.Socket creation failed: %v\n", err)
		os.Exit(1)
	}
	defer unix.Close(socketFd)

	desiredTimeout := 2*time.Second + 500*time.Millisecond
	if err := sample.SetSocketTimeout(socketFd, desiredTimeout); err != nil {
		fmt.Fprintf(os.Stderr, "Assertion failed: SetSocketTimeout failed: %v\n", err)
		os.Exit(1)
	}

	optTv, err := sample.GetSocketReceiveTimeout(socketFd)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Assertion failed: GetSocketReceiveTimeout failed: %v\n", err)
		os.Exit(1)
	}
	if optTv == nil || optTv.Sec != 2 || optTv.Usec != 500_000 {
		fmt.Fprintf(os.Stderr, "Assertion failed: GetsockoptTimeval unexpected value: got %+v\n", optTv)
		os.Exit(1)
	}

	// Helper duration conversion checks
	dur := sample.TimevalToDuration(*optTv)
	if dur != desiredTimeout {
		fmt.Fprintf(os.Stderr, "Assertion failed: TimevalToDuration mismatch: got %v, expected %v\n", dur, desiredTimeout)
		os.Exit(1)
	}

	fmt.Println("All Timeval contract assertions passed.")
}

package sample

import (
	"time"

	"golang.org/x/sys/unix"
)

// DurationToTimeval converts a standard time.Duration to unix.Timeval.
func DurationToTimeval(d time.Duration) unix.Timeval {
	return unix.NsecToTimeval(d.Nanoseconds())
}

// TimevalToDuration converts unix.Timeval to a standard time.Duration.
func TimevalToDuration(tv unix.Timeval) time.Duration {
	return time.Duration(tv.Nano())
}

// GetCurrentTimeval gets current system time as unix.Timeval.
func GetCurrentTimeval() (unix.Timeval, error) {
	var tv unix.Timeval
	err := unix.Gettimeofday(&tv)
	return tv, err
}

// SetSocketTimeout sets send and receive timeouts on a socket fd using unix.Timeval.
func SetSocketTimeout(fd int, timeout time.Duration) error {
	tv := DurationToTimeval(timeout)
	if err := unix.SetsockoptTimeval(fd, unix.SOL_SOCKET, unix.SO_RCVTIMEO, &tv); err != nil {
		return err
	}
	return unix.SetsockoptTimeval(fd, unix.SOL_SOCKET, unix.SO_SNDTIMEO, &tv)
}

// GetSocketReceiveTimeout retrieves the receive timeout as unix.Timeval from a socket fd.
func GetSocketReceiveTimeout(fd int) (*unix.Timeval, error) {
	return unix.GetsockoptTimeval(fd, unix.SOL_SOCKET, unix.SO_RCVTIMEO)
}