embed smartctl in the windows binary (#1362)

agent/tools/fetchsmartctl/main.go

@@ -0,0 +1,130 @@
+package main
+
+import (
+	"crypto/sha1"
+	"crypto/sha256"
+	"encoding/hex"
+	"flag"
+	"fmt"
+	"hash"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+// Download smartctl.exe from the given URL and save it to the given destination.
+// This is used to embed smartctl.exe in the Windows build.
+
+func main() {
+	url := flag.String("url", "", "URL to download smartctl.exe from (required)")
+	out := flag.String("out", "", "Destination path for smartctl.exe (required)")
+	sha := flag.String("sha", "", "Optional SHA1/SHA256 checksum for integrity validation")
+	force := flag.Bool("force", false, "Force re-download even if destination exists")
+	flag.Parse()
+
+	if *url == "" || *out == "" {
+		fatalf("-url and -out are required")
+	}
+
+	if !*force {
+		if info, err := os.Stat(*out); err == nil && info.Size() > 0 {
+			fmt.Println("smartctl.exe already present, skipping download")
+			return
+		}
+	}
+
+	if err := downloadFile(*url, *out, *sha); err != nil {
+		fatalf("download failed: %v", err)
+	}
+}
+
+func downloadFile(url, dest, shaHex string) error {
+	// Prepare destination
+	if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
+		return fmt.Errorf("create dir: %w", err)
+	}
+
+	// HTTP client
+	client := &http.Client{Timeout: 60 * time.Second}
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return fmt.Errorf("new request: %w", err)
+	}
+	req.Header.Set("User-Agent", "beszel-fetchsmartctl/1.0")
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return fmt.Errorf("http get: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return fmt.Errorf("unexpected HTTP status: %s", resp.Status)
+	}
+
+	tmp := dest + ".tmp"
+	f, err := os.OpenFile(tmp, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0o644)
+	if err != nil {
+		return fmt.Errorf("open tmp: %w", err)
+	}
+
+	// Determine hash algorithm based on length (SHA1=40, SHA256=64)
+	var hasher hash.Hash
+	if shaHex := strings.TrimSpace(shaHex); shaHex != "" {
+		cleanSha := strings.ToLower(strings.ReplaceAll(shaHex, " ", ""))
+		switch len(cleanSha) {
+		case 40:
+			hasher = sha1.New()
+		case 64:
+			hasher = sha256.New()
+		default:
+			f.Close()
+			os.Remove(tmp)
+			return fmt.Errorf("unsupported hash length: %d (expected 40 for SHA1 or 64 for SHA256)", len(cleanSha))
+		}
+	}
+
+	var mw io.Writer = f
+	if hasher != nil {
+		mw = io.MultiWriter(f, hasher)
+	}
+	if _, err := io.Copy(mw, resp.Body); err != nil {
+		f.Close()
+		os.Remove(tmp)
+		return fmt.Errorf("write tmp: %w", err)
+	}
+	if err := f.Close(); err != nil {
+		os.Remove(tmp)
+		return fmt.Errorf("close tmp: %w", err)
+	}
+
+	if hasher != nil && shaHex != "" {
+		cleanSha := strings.ToLower(strings.ReplaceAll(strings.TrimSpace(shaHex), " ", ""))
+		got := strings.ToLower(hex.EncodeToString(hasher.Sum(nil)))
+		if got != cleanSha {
+			os.Remove(tmp)
+			return fmt.Errorf("hash mismatch: got %s want %s", got, cleanSha)
+		}
+	}
+
+	// Make executable and move into place
+	if err := os.Chmod(tmp, 0o755); err != nil {
+		os.Remove(tmp)
+		return fmt.Errorf("chmod: %w", err)
+	}
+	if err := os.Rename(tmp, dest); err != nil {
+		os.Remove(tmp)
+		return fmt.Errorf("rename: %w", err)
+	}
+
+	fmt.Println("smartctl.exe downloaded to", dest)
+	return nil
+}
+
+func fatalf(format string, a ...any) {
+	fmt.Fprintf(os.Stderr, format+"\n", a...)
+	os.Exit(1)
+}