allow absolute paths to isos in checksum files

common/iso_config.go

@@ -95,7 +95,6 @@ func (c *ISOConfig) Prepare(ctx *interpolate.Context) (warnings []string, errs [
 							errs = append(errs, err)
 							return warnings, errs
 						}
-
 					case "":
 						break
 					default:
@@ -153,7 +152,8 @@ func (c *ISOConfig) parseCheckSumFile(rd *bufio.Reader) error {
 
 	filename := filepath.Base(u.Path)
 
-	errNotFound := fmt.Errorf("No checksum for %q or %q found at: %s", filename, relpath, c.ISOChecksumURL)
+	errNotFound := fmt.Errorf("No checksum for %q, %q or %q found at: %s",
+		filename, relpath, u.Path, c.ISOChecksumURL)
 	for {
 		line, err := rd.ReadString('\n')
 		if err != nil && line == "" {
@@ -163,24 +163,28 @@ func (c *ISOConfig) parseCheckSumFile(rd *bufio.Reader) error {
 		if len(parts) < 2 {
 			continue
 		}
+		options := []string{filename, relpath, "./" + relpath, u.Path}
 		if strings.ToLower(parts[0]) == c.ISOChecksumType {
 			// BSD-style checksum
-			if parts[1] == fmt.Sprintf("(%s)", filename) || parts[1] == fmt.Sprintf("(%s)", relpath) ||
+			for _, match := range options {
-				parts[1] == fmt.Sprintf("(./%s)", relpath) {
+				if parts[1] == fmt.Sprintf("(%s)", match) {
 					c.ISOChecksum = parts[3]
 					return nil
 				}
+			}
 		} else {
 			// Standard checksum
 			if parts[1][0] == '*' {
 				// Binary mode
 				parts[1] = parts[1][1:]
 			}
-			if parts[1] == filename || parts[1] == relpath || parts[1] == "./"+relpath {
+			for _, match := range options {
+				if parts[1] == match {
 					c.ISOChecksum = parts[0]
 					return nil
 				}
 			}
 		}
+	}
 	return errNotFound
 }