feat: add show CLI tool to parse and display quotes

tools/show/README.md

@@ -0,0 +1,46 @@
+# `show` CLI tool
+
+This binary is a CLI tool for parsing and displaying Intel TDX quotes.
+
+The tool's input is a quote.
+
+The tool's output is the quote in any specified format to either standard out
+or directly to a file.
+
+## Usage
+
+```
+./show [options...]
+```
+
+### `-in`
+
+This flag provides the path to the quote to show. Stdin is "-".
+
+### `-inform`
+
+The format that input takes. One of
+
+*   `bin`: for a raw binary quote.
+*   `proto`: A binary serialized `tdx.QuoteV4` message.
+*   `textproto`: The `tdx.QuoteV4` message in textproto format.
+
+Default value is `bin`.
+
+### `-out`
+
+Path to output file to write quote to.
+
+Default is empty, interpreted as stdout.
+
+### `-outform`
+
+The format that output takes. Currently only `textproto` is supported.
+
+Default value is `textproto`.
+
+### `-verbosity`
+
+Used to set the verbosity of logger, where higher number means more verbose output.
+
+Default value is `0`.

tools/show/show.go

@@ -0,0 +1,162 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package main implements a CLI tool for showing Intel TDX quotes.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/google/go-tdx-guest/abi"
+	pb "github.com/google/go-tdx-guest/proto/tdx"
+	"github.com/google/logger"
+	"google.golang.org/protobuf/encoding/prototext"
+	"google.golang.org/protobuf/proto"
+)
+
+var (
+	infile = flag.String("in", "-", "Path to the TDX quote to show. Stdin is \"-\".")
+	inform = flag.String("inform", "bin", "The input format for the TDX quote. One of \"bin\", \"proto\", \"textproto\".")
+	out    = flag.String("out", "", "Path to output file to write attestation report to. "+
+		"If unset, outputs to stdout.")
+	outform   = flag.String("outform", "textproto", "The format of the output attestation report. Currently only  \"textproto\" is supported.")
+	verbosity = flag.Int("verbosity", 0, "The output verbosity. Higher number means more verbose output.")
+)
+
+func parseQuoteBytes(b []byte) (any, error) {
+	quote, err := abi.QuoteToProto(b)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse the TDX Quote from %q: %v", *infile, err)
+	}
+
+	return quote, nil
+}
+
+func parseQuote(b []byte) (any, error) {
+	switch *inform {
+	case "bin":
+		return parseQuoteBytes(b)
+	case "proto":
+		result := &pb.QuoteV4{}
+		if err := proto.Unmarshal(b, result); err != nil {
+			return nil, fmt.Errorf("could not parse %q as proto: %v", *infile, err)
+		}
+		return result, nil
+	case "textproto":
+		result := &pb.QuoteV4{}
+		if err := prototext.Unmarshal(b, result); err != nil {
+			return nil, fmt.Errorf("could not parse %q as textproto: %v", *infile, err)
+		}
+		return result, nil
+	default:
+		return nil, fmt.Errorf("unknown value -inform=%s", *inform)
+	}
+}
+
+func readQuote() (any, error) {
+	var in io.Reader
+	var f *os.File
+	if *infile == "-" {
+		in = os.Stdin
+	} else {
+		file, err := os.Open(*infile)
+		if err != nil {
+			return nil, fmt.Errorf("could not open %q: %v", *infile, err)
+		}
+		f = file
+		in = file
+	}
+	defer func() {
+		if f != nil {
+			f.Close()
+		}
+	}()
+
+	contents, err := io.ReadAll(in)
+	if err != nil {
+		return nil, fmt.Errorf("could not read %q: %v", *infile, err)
+	}
+	return parseQuote(contents)
+}
+
+func marshalAndWriteBytes(quote any, out io.Writer) error {
+	switch q := quote.(type) {
+	case *pb.QuoteV4:
+		mo := prototext.MarshalOptions{
+			Multiline: true,
+			Indent:    "  ",
+			EmitASCII: true,
+		}
+		bytes, err := mo.Marshal(q)
+		if err != nil {
+			return err
+		}
+		if _, err := out.Write(bytes); err != nil {
+			return err
+		}
+		return nil
+	default:
+		return fmt.Errorf("unsupported quote type: %T", quote)
+	}
+}
+
+func outWriter() (io.Writer, *os.File, error) {
+	if *out == "" {
+		return os.Stdout, nil, nil
+	}
+	file, err := os.Create(*out)
+	if err != nil {
+		return nil, nil, err
+	}
+	return file, file, nil
+}
+
+func writeQuote(quote any, out io.Writer) error {
+	switch *outform {
+	case "textproto":
+		return marshalAndWriteBytes(quote, out)
+	default:
+		return fmt.Errorf("unknown value -outform=%s", *outform)
+	}
+}
+
+func main() {
+	logger.Init("", false, false, os.Stdout)
+	flag.Parse()
+	logger.SetLevel(logger.Level(*verbosity))
+
+	quote, err := readQuote()
+	if err != nil {
+		logger.Fatal(err)
+	}
+	logger.V(1).Info("TDX Quote parsed successfully")
+
+	outwriter, filetoclose, err := outWriter()
+	if err != nil {
+		logger.Fatalf("failed to open output file: %v", err)
+	}
+	defer func() {
+		if filetoclose != nil {
+			filetoclose.Close()
+		}
+	}()
+
+	err2 := writeQuote(quote, outwriter)
+	if err2 != nil {
+		logger.Fatal(err2)
+	}
+}