omaha: add helper method for computing package metadata

omaha/package.go

@@ -0,0 +1,112 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// 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 omaha
+
+import (
+	"crypto/sha1"
+	"crypto/sha256"
+	"encoding/base64"
+	"errors"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+var (
+	PackageHashMismatchError = errors.New("package hash is invalid")
+	PackageSizeMismatchError = errors.New("package size is invalid")
+)
+
+// Package represents a single downloadable file. The Sha256 attribute
+// is not a standard part of the Omaha protocol which only uses Sha1.
+type Package struct {
+	Name     string `xml:"name,attr"`
+	Sha1     string `xml:"hash,attr"`
+	Sha256   string `xml:"sha256,attr,omitempty"`
+	Size     uint64 `xml:"size,attr"`
+	Required bool   `xml:"required,attr"`
+}
+
+func (p *Package) FromPath(name string) error {
+	f, err := os.Open(name)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	err = p.FromReader(f)
+	if err != nil {
+		return err
+	}
+
+	p.Name = filepath.Base(name)
+	return nil
+}
+
+func (p *Package) FromReader(r io.Reader) error {
+	sha1b64, sha256b64, n, err := multihash(r)
+	if err != nil {
+		return err
+	}
+
+	p.Sha1 = sha1b64
+	p.Sha256 = sha256b64
+	p.Size = uint64(n)
+	return nil
+}
+
+func (p *Package) Verify(dir string) error {
+	f, err := os.Open(filepath.Join(dir, p.Name))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	return p.VerifyReader(f)
+}
+
+func (p *Package) VerifyReader(r io.Reader) error {
+	sha1b64, sha256b64, n, err := multihash(r)
+	if err != nil {
+		return err
+	}
+
+	if p.Size != uint64(n) {
+		return PackageSizeMismatchError
+	}
+
+	if p.Sha1 != sha1b64 {
+		return PackageHashMismatchError
+	}
+
+	// Allow Sha256 to be empty since it is a protocol extension.
+	if p.Sha256 != "" && p.Sha256 != sha256b64 {
+		return PackageHashMismatchError
+	}
+
+	return nil
+}
+
+func multihash(r io.Reader) (sha1b64, sha256b64 string, n int64, err error) {
+	h1 := sha1.New()
+	h256 := sha256.New()
+	if n, err = io.Copy(io.MultiWriter(h1, h256), r); err != nil {
+		return
+	}
+
+	sha1b64 = base64.StdEncoding.EncodeToString(h1.Sum(nil))
+	sha256b64 = base64.StdEncoding.EncodeToString(h256.Sum(nil))
+	return
+}

omaha/package_test.go

@@ -0,0 +1,144 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// 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 omaha
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/kylelemons/godebug/pretty"
+)
+
+func TestPackageFromPath(t *testing.T) {
+	expect := Package{
+		Name:     "null",
+		Sha1:     "2jmj7l5rSw0yVb/vlWAYkK/YBwk=",
+		Sha256:   "47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=",
+		Size:     0,
+		Required: false,
+	}
+
+	p := Package{}
+	if err := p.FromPath("/dev/null"); err != nil {
+		t.Fatal(err)
+	}
+
+	if diff := pretty.Compare(expect, p); diff != "" {
+		t.Errorf("Hashing /dev/null failed: %v", diff)
+	}
+}
+
+func TestProtocolFromReader(t *testing.T) {
+	data := strings.NewReader("testing\n")
+	expect := Package{
+		Name:     "",
+		Sha1:     "mAFznarkTsUpPU4fU9P00tQm2Rw=",
+		Sha256:   "EqYfThc/s6EcBdZHH3Ryj3YjG0pfzZZnzvOvh6OuTcI=",
+		Size:     8,
+		Required: false,
+	}
+
+	p := Package{}
+	if err := p.FromReader(data); err != nil {
+		t.Fatal(err)
+	}
+
+	if diff := pretty.Compare(expect, p); diff != "" {
+		t.Errorf("Hashing failed: %v", diff)
+	}
+}
+
+func TestPackageVerify(t *testing.T) {
+	p := Package{
+		Name:     "null",
+		Sha1:     "2jmj7l5rSw0yVb/vlWAYkK/YBwk=",
+		Sha256:   "47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=",
+		Size:     0,
+		Required: false,
+	}
+
+	if err := p.Verify("/dev"); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestPackageVerifyNoSha256(t *testing.T) {
+	p := Package{
+		Name:     "null",
+		Sha1:     "2jmj7l5rSw0yVb/vlWAYkK/YBwk=",
+		Sha256:   "",
+		Size:     0,
+		Required: false,
+	}
+
+	if err := p.Verify("/dev"); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestPackageVerifyBadSize(t *testing.T) {
+	p := Package{
+		Name:     "null",
+		Sha1:     "2jmj7l5rSw0yVb/vlWAYkK/YBwk=",
+		Sha256:   "47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=",
+		Size:     1,
+		Required: false,
+	}
+
+	err := p.Verify("/dev")
+	if err == nil {
+		t.Error("verify passed")
+	}
+	if err != PackageSizeMismatchError {
+		t.Error(err)
+	}
+
+}
+
+func TestPackageVerifyBadSha1(t *testing.T) {
+	p := Package{
+		Name:     "null",
+		Sha1:     "xxxxxxxxxxxxxxxxxxxxxxxxxxx=",
+		Sha256:   "47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=",
+		Size:     0,
+		Required: false,
+	}
+
+	err := p.Verify("/dev")
+	if err == nil {
+		t.Error("verify passed")
+	}
+	if err != PackageHashMismatchError {
+		t.Error(err)
+	}
+}
+
+func TestPackageVerifyBadSha256(t *testing.T) {
+	p := Package{
+		Name:     "null",
+		Sha1:     "2jmj7l5rSw0yVb/vlWAYkK/YBwk=",
+		Sha256:   "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx=",
+		Size:     0,
+		Required: false,
+	}
+
+	err := p.Verify("/dev")
+	if err == nil {
+		t.Error("verify passed")
+	}
+	if err != PackageHashMismatchError {
+		t.Error(err)
+	}
+}

omaha/protocol.go

@@ -224,19 +224,21 @@ type Manifest struct {
 	Version  string     `xml:"version,attr"`
 }
 
-type Package struct {
-	Hash     string `xml:"hash,attr"`
-	Name     string `xml:"name,attr"`
-	Size     uint64 `xml:"size,attr"`
-	Required bool   `xml:"required,attr"`
-}
-
 func (m *Manifest) AddPackage() *Package {
 	p := &Package{}
 	m.Packages = append(m.Packages, p)
 	return p
 }
 
+func (m *Manifest) AddPackageFromPath(path string) (*Package, error) {
+	p := &Package{}
+	if err := p.FromPath(path); err != nil {
+		return nil, err
+	}
+	m.Packages = append(m.Packages, p)
+	return p, nil
+}
+
 func (m *Manifest) AddAction(event string) *Action {
 	a := &Action{Event: event}
 	m.Actions = append(m.Actions, a)

omaha/protocol_test.go

@@ -88,7 +88,7 @@ func ExampleNewResponse() {
 	u.AddURL("http://localhost/updates")
 	m := u.AddManifest("9999.0.0")
 	k := m.AddPackage()
-	k.Hash = "+LXvjiaPkeYDLHoNKlf9qbJwvnk="
+	k.Sha1 = "+LXvjiaPkeYDLHoNKlf9qbJwvnk="
 	k.Name = "update.gz"
 	k.Size = 67546213
 	k.Required = true
@@ -118,7 +118,7 @@ func ExampleNewResponse() {
 	//    </urls>
 	//    <manifest version="9999.0.0">
 	//     <packages>
-	//      <package hash="+LXvjiaPkeYDLHoNKlf9qbJwvnk=" name="update.gz" size="67546213" required="true"></package>
+	//      <package name="update.gz" hash="+LXvjiaPkeYDLHoNKlf9qbJwvnk=" size="67546213" required="true"></package>
 	//     </packages>
 	//     <actions>
 	//      <action event="postinstall" DisplayVersion="9999.0.0" sha256="0VAlQW3RE99SGtSB5R4m08antAHO8XDoBMKDyxQT/Mg=" IsDeltaPayload="true" DisablePayloadBackoff="true"></action>