updater: add initial skeleton

1 files changed, 85 insertions, 0 deletions

diff --git a/updater/versions.go b/updater/versions.go
new file mode 100644
index 00000000..a5b6c258
--- /dev/null
+++ b/updater/versions.go
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package updater
+
+import (
+	"errors"
+	"fmt"
+	"golang.zx2c4.com/wireguard/windows/version"
+	"runtime"
+	"strconv"
+	"strings"
+)
+
+func versionNewerThanUs(candidate string) (bool, error) {
+	candidateParts := strings.Split(candidate, ".")
+	ourParts := strings.Split(version.WireGuardWindowsVersion, ".")
+	if len(candidateParts) == 0 || len(ourParts) == 0 {
+		return false, errors.New("Empty version")
+	}
+	l := len(candidateParts)
+	if len(ourParts) > l {
+		l = len(ourParts)
+	}
+	for i := 0; i < l; i++ {
+		var err error
+		cP, oP := uint64(0), uint64(0)
+		if i < len(candidateParts) {
+			if len(candidateParts[i]) == 0 {
+				return false, errors.New("Empty version part")
+			}
+			cP, err = strconv.ParseUint(candidateParts[i], 10, 16)
+			if err != nil {
+				return false, errors.New("Invalid version integer part")
+			}
+		}
+		if i < len(ourParts) {
+			if len(ourParts[i]) == 0 {
+				return false, errors.New("Empty version part")
+			}
+			oP, err = strconv.ParseUint(ourParts[i], 10, 16)
+			if err != nil {
+				return false, errors.New("Invalid version integer part")
+			}
+		}
+		if cP == oP {
+			continue
+		}
+		return cP > oP, nil
+	}
+	return false, nil
+}
+
+func findCandidate(candidates fileList) (*UpdateFound, error) {
+	var arch string
+	if runtime.GOARCH == "amd64" {
+		arch = "amd64"
+	} else if runtime.GOARCH == "386" {
+		arch = "x86"
+	} else if runtime.GOARCH == "arm64" {
+		arch = "arm64"
+	} else {
+		return nil, errors.New("Invalid GOARCH")
+	}
+	prefix := fmt.Sprintf(msiArchPrefix, arch)
+	suffix := msiSuffix
+	for name, hash := range candidates {
+		if strings.HasPrefix(name, prefix) && strings.HasSuffix(name, suffix) {
+			version := strings.TrimSuffix(strings.TrimPrefix(name, prefix), suffix)
+			if len(version) > 128 {
+				return nil, errors.New("Version length is too long")
+			}
+			newer, err := versionNewerThanUs(version)
+			if err != nil {
+				return nil, err
+			}
+			if newer {
+				return &UpdateFound{name, hash}, nil
+			}
+		}
+	}
+	return nil, nil
+}