golang.org/x/sys v0.0.0-20181122145206-62eef0e2fa9b: unix.Setrlimit

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.Setrlimit in pkg:golang/golang.org/x/sys@v0.0.0-20181122145206-62eef0e2fa9b
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/sys@v0.0.0-20181122145206-62eef0e2fa9b
Demonstrate these symbols/APIs:
  - golang.org/x/sys/unix.Setrlimit

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:sha256:3c08f36229ac5653a04e7b0bf0f60eb7cf89b47c7a1a7eae91c7c2efd530fc57","contract":["unix.Setrlimit sets resource soft limits within allowable bounds for the calling process, verifiable via unix.Getrlimit","unix.Setrlimit returns unix.EINVAL when invoked with an invalid resource identifier","unix.Setrlimit returns unix.EFAULT when invoked with a nil pointer for the limit struct"],"goal":"verify golang.org/x/sys/unix.Setrlimit in pkg:golang/golang.org/x/sys@v0.0.0-20181122145206-62eef0e2fa9b","kind":"HOW","packages":["pkg:golang/golang.org/x/sys@v0.0.0-20181122145206-62eef0e2fa9b"],"schemaVersion":1,"symbols":["golang.org/x/sys/unix.Setrlimit"]},"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@v0.0.0-20181122145206-62eef0e2fa9b"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/sys@v0.0.0-20181122145206-62eef0e2fa9b","symbols":["golang.org/x/sys/unix.Setrlimit"],"verifierAdapter":"golang@1"}

module example.com/rlimitsample

go 1.26.6

require golang.org/x/sys v0.0.0-20181122145206-62eef0e2fa9b

golang.org/x/sys v0.0.0-20181122145206-62eef0e2fa9b h1:MQE+LT/ABUuuvEZ+YQAMSXindAdUh7slEmAkup74op4=
golang.org/x/sys v0.0.0-20181122145206-62eef0e2fa9b/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=

package rlimitsample

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

// SetLimit adjusts the soft and hard resource limits for the specified resource.
func SetLimit(resource int, soft, hard uint64) error {
	lim := unix.Rlimit{
		Cur: soft,
		Max: hard,
	}
	return unix.Setrlimit(resource, &lim)
}

// GetLimit retrieves the current soft and hard resource limits for the specified resource.
func GetLimit(resource int) (uint64, uint64, error) {
	var lim unix.Rlimit
	if err := unix.Getrlimit(resource, &lim); err != nil {
		return 0, 0, err
	}
	return lim.Cur, lim.Max, nil
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/sys/unix.Setrlimit in pkg:golang/golang.org/x/sys@v0.0.0-20181122145206-62eef0e2fa9b",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/sys@v0.0.0-20181122145206-62eef0e2fa9b"
  ],
  "symbols": [
    "golang.org/x/sys/unix.Setrlimit"
  ]
}

package main

import (
	"errors"
	"fmt"
	"os"

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

func main() {
	// Assertion 1: unix.Setrlimit updates resource soft limit within allowable bounds, verified via unix.Getrlimit
	var origLim unix.Rlimit
	if err := unix.Getrlimit(unix.RLIMIT_NOFILE, &origLim); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: initial Getrlimit failed: %v\n", err)
		os.Exit(1)
	}

	targetCur := origLim.Cur
	if origLim.Cur > 64 {
		targetCur = origLim.Cur - 1
	}

	tempLim := unix.Rlimit{
		Cur: targetCur,
		Max: origLim.Max,
	}

	if err := unix.Setrlimit(unix.RLIMIT_NOFILE, &tempLim); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: Setrlimit failed: %v\n", err)
		os.Exit(1)
	}

	var verifiedLim unix.Rlimit
	if err := unix.Getrlimit(unix.RLIMIT_NOFILE, &verifiedLim); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: Getrlimit after set failed: %v\n", err)
		os.Exit(1)
	}

	if verifiedLim.Cur != targetCur {
		fmt.Fprintf(os.Stderr, "FAIL: Getrlimit returned Cur=%d, expected %d\n", verifiedLim.Cur, targetCur)
		os.Exit(1)
	}

	// Verify via package helper functions
	if err := rlimitsample.SetLimit(unix.RLIMIT_NOFILE, origLim.Cur, origLim.Max); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: rlimitsample.SetLimit restore failed: %v\n", err)
		os.Exit(1)
	}

	restoredCur, restoredMax, err := rlimitsample.GetLimit(unix.RLIMIT_NOFILE)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: rlimitsample.GetLimit failed: %v\n", err)
		os.Exit(1)
	}
	if restoredCur != origLim.Cur || restoredMax != origLim.Max {
		fmt.Fprintf(os.Stderr, "FAIL: restored limit mismatch: got (%d, %d), expected (%d, %d)\n", restoredCur, restoredMax, origLim.Cur, origLim.Max)
		os.Exit(1)
	}

	// Assertion 2: unix.Setrlimit returns unix.EINVAL for invalid resource identifier
	if err := unix.Setrlimit(-1, &origLim); err == nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected error for invalid resource -1, got nil\n")
		os.Exit(1)
	} else if !errors.Is(err, unix.EINVAL) {
		fmt.Fprintf(os.Stderr, "FAIL: expected EINVAL for resource -1, got: %v\n", err)
		os.Exit(1)
	}

	// Assertion 3: unix.Setrlimit returns unix.EFAULT when passed nil pointer
	if err := unix.Setrlimit(unix.RLIMIT_NOFILE, nil); err == nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected error for nil pointer, got nil\n")
		os.Exit(1)
	} else if !errors.Is(err, unix.EFAULT) {
		fmt.Fprintf(os.Stderr, "FAIL: expected EFAULT for nil pointer, got: %v\n", err)
		os.Exit(1)
	}

	fmt.Println("PASS: golang.org/x/sys/unix.Setrlimit contract verified")
}