golang.org/x/sys v0.41.0: unix.Statfs_t

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.Statfs_t in pkg:golang/golang.org/x/sys@v0.41.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/sys@v0.41.0
Demonstrate these symbols/APIs:
  - golang.org/x/sys/unix.Statfs_t

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:sha256:9d07d47851f40fceb578c5175b153070f70741a1f6fc724d7e1b2347cce2db9d","contract":["unix.Statfs populates unix.Statfs_t with positive block size, total blocks, and maximum filename length","unix.Fstatfs on an open file descriptor populates unix.Statfs_t with matching filesystem type and block size","unix.Statfs on a non-existent path returns an error matching ENOENT"],"goal":"verify golang.org/x/sys/unix.Statfs_t in pkg:golang/golang.org/x/sys@v0.41.0","kind":"HOW","packages":["pkg:golang/golang.org/x/sys@v0.41.0"],"schemaVersion":1,"symbols":["golang.org/x/sys/unix.Statfs_t"]},"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@v0.41.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/sys@v0.41.0","symbols":["golang.org/x/sys/unix.Statfs_t"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require golang.org/x/sys v0.41.0

golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=

package main

import (
	"fmt"
	"os"

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

func main() {
	var stat unix.Statfs_t
	if err := unix.Statfs(".", &stat); err != nil {
		fmt.Fprintf(os.Stderr, "unix.Statfs failed: %v\n", err)
		os.Exit(1)
	}

	totalBytes := uint64(stat.Bsize) * stat.Blocks
	freeBytes := uint64(stat.Bsize) * stat.Bavail

	fmt.Printf("Filesystem Type: 0x%X\n", stat.Type)
	fmt.Printf("Block Size: %d bytes\n", stat.Bsize)
	fmt.Printf("Total Space: %d bytes\n", totalBytes)
	fmt.Printf("Available Space: %d bytes\n", freeBytes)
	fmt.Printf("Max Filename Length: %d\n", stat.Namelen)
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/sys/unix.Statfs_t in pkg:golang/golang.org/x/sys@v0.41.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/sys@v0.41.0"
  ],
  "symbols": [
    "golang.org/x/sys/unix.Statfs_t"
  ]
}

package main

import (
	"errors"
	"fmt"
	"os"

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

func main() {
	if err := runContractTests(); err != nil {
		fmt.Fprintf(os.Stderr, "Contract test failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("All contract assertions passed.")
}

func runContractTests() error {
	// 1. unix.Statfs populates unix.Statfs_t with positive block size, total blocks, and maximum filename length
	tmpDir, err := os.MkdirTemp("", "statfs_contract_*")
	if err != nil {
		return fmt.Errorf("failed to create temporary dir: %w", err)
	}
	defer os.RemoveAll(tmpDir)

	var stat unix.Statfs_t
	if err := unix.Statfs(tmpDir, &stat); err != nil {
		return fmt.Errorf("unix.Statfs failed on tmpDir: %w", err)
	}

	if stat.Bsize <= 0 {
		return fmt.Errorf("expected positive Bsize in unix.Statfs_t, got %d", stat.Bsize)
	}
	if stat.Blocks == 0 {
		return fmt.Errorf("expected non-zero Blocks in unix.Statfs_t, got %d", stat.Blocks)
	}
	if stat.Namelen <= 0 {
		return fmt.Errorf("expected positive Namelen in unix.Statfs_t, got %d", stat.Namelen)
	}

	// 2. unix.Fstatfs on an open file descriptor populates unix.Statfs_t with matching filesystem type and block size
	tmpFile, err := os.CreateTemp(tmpDir, "statfs_file_*")
	if err != nil {
		return fmt.Errorf("failed to create temporary file: %w", err)
	}
	defer tmpFile.Close()

	var fstat unix.Statfs_t
	if err := unix.Fstatfs(int(tmpFile.Fd()), &fstat); err != nil {
		return fmt.Errorf("unix.Fstatfs failed: %w", err)
	}

	if fstat.Type != stat.Type {
		return fmt.Errorf("expected Fstatfs Type %d to match Statfs Type %d", fstat.Type, stat.Type)
	}
	if fstat.Bsize != stat.Bsize {
		return fmt.Errorf("expected Fstatfs Bsize %d to match Statfs Bsize %d", fstat.Bsize, stat.Bsize)
	}
	if fstat.Blocks != stat.Blocks {
		return fmt.Errorf("expected Fstatfs Blocks %d to match Statfs Blocks %d", fstat.Blocks, stat.Blocks)
	}

	// 3. unix.Statfs on a non-existent path returns an error matching ENOENT
	nonExistentPath := tmpDir + "/non_existent_subpath_for_statfs"
	var missingStat unix.Statfs_t
	err = unix.Statfs(nonExistentPath, &missingStat)
	if err == nil {
		return fmt.Errorf("expected error for non-existent path, got nil")
	}
	if !errors.Is(err, unix.ENOENT) {
		return fmt.Errorf("expected ENOENT error for non-existent path, got: %w", err)
	}

	return nil
}