parsesnp: add slog

tools/parsesnp.go

@@ -5,7 +5,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"io"
-	"log"
+	"log/slog"
 	"os"
 
 	"github.com/google/go-sev-guest/abi"
@@ -45,13 +45,26 @@ type Report struct {
 }
 
 func main() {
+	if err := run(); err != nil {
+		os.Exit(1)
+	}
+}
+
+func run() (retErr error) {
+	logger := slog.Default()
+	defer func() {
+		if retErr != nil {
+			logger.Error(retErr.Error())
+		}
+	}()
+
 	data, err := io.ReadAll(os.Stdin)
 	if err != nil {
-		log.Fatalf("failed to read input: %v", err)
+		return fmt.Errorf("failed to read input: %w", err)
 	}
 	data, err = hex.DecodeString(string(data))
 	if err != nil {
-		log.Fatalf("failed to decode input: %v", err)
+		return fmt.Errorf("failed to decode input: %w", err)
 	}
 
 	var r Report
@@ -79,11 +92,11 @@ func main() {
 
 	signerInfo, err := abi.ParseSignerInfo(binary.LittleEndian.Uint32(data[0x48:0x4C]))
 	if err != nil {
-		log.Printf("failed to parse signer info: %v", err)
+		return fmt.Errorf("failed to parse signer info: %w", err)
 	}
 	r.SignerInfo = abi.ComposeSignerInfo(signerInfo)
 	if err := mbz(data, 0x4C, 0x50); err != nil {
-		log.Printf("%v", err)
+		return err
 	}
 	fmt.Printf("SignerInfo: %v\n", r.SignerInfo)
 	r.ReportData = clone(data[0x50:0x90])
@@ -102,7 +115,7 @@ func main() {
 	fmt.Printf("ReportIdMa: %x\n", r.ReportIdMa)
 	r.ReportedTcb = binary.LittleEndian.Uint64(data[0x180:0x188])
 	if err := mbz(data, 0x188, 0x1A0); err != nil {
-		fmt.Printf("%v", err)
+		return err
 	}
 
 	r.ChipId = clone(data[0x1A0:0x1E0])
@@ -116,7 +129,7 @@ func main() {
 	r.CurrentMajor = uint32(data[0x1EA])
 	fmt.Printf("CurrentMajor: %d\n", r.CurrentMajor)
 	if err := mbz(data, 0x1EB, 0x1EC); err != nil {
-		fmt.Printf("%v", err)
+		return err
 	}
 	r.CommittedBuild = uint32(data[0x1EC])
 	fmt.Printf("CommittedBuild: %d\n", r.CommittedBuild)
@@ -125,20 +138,21 @@ func main() {
 	r.CommittedMajor = uint32(data[0x1EE])
 	fmt.Printf("CommittedMajor: %d\n", r.CommittedMajor)
 	if err := mbz(data, 0x1EF, 0x1F0); err != nil {
-		fmt.Printf("%v", err)
+		return err
 	}
 	r.LaunchTcb = binary.LittleEndian.Uint64(data[0x1F0:0x1F8])
 	if err := mbz(data, 0x1F8, signatureOffset); err != nil {
-		fmt.Printf("%v", err)
+		return err
 	}
 
 	if r.SignatureAlgo == abi.SignEcdsaP384Sha384 {
 		if err := mbz(data, signatureOffset+abi.EcdsaP384Sha384SignatureSize, abi.ReportSize); err != nil {
-			fmt.Printf("%v", err)
+			return err
 		}
 	}
 	r.Signature = clone(data[signatureOffset:abi.ReportSize])
 	fmt.Printf("Signature: %x\n", r.Signature)
+	return nil
 }
 
 func clone(b []byte) []byte {