builder/common: step to create floppy disks

builder/common/step_create_floppy.go

+package common
+
+import (
+	"fmt"
+	"github.com/mitchellh/go-fs"
+	"github.com/mitchellh/go-fs/fat"
+	"github.com/mitchellh/multistep"
+	"github.com/mitchellh/packer/packer"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+)
+
+// StepCreateFloppy will create a floppy disk with the given files.
+// The floppy disk doesn't support sub-directories. Only files at the
+// root level are supported.
+type StepCreateFloppy struct {
+	Files []string
+}
+
+func (s *StepCreateFloppy) Run(state map[string]interface{}) multistep.StepAction {
+	if len(s.Files) == 0 {
+		log.Println("No floppy files specified. Floppy disk will not be made.")
+		return multistep.ActionContinue
+	}
+
+	ui := state["ui"].(packer.Ui)
+	ui.Say("Creating floppy disk...")
+
+	// Create a temporary file to be our floppy drive
+	floppyF, err := ioutil.TempFile("", "packer")
+	if err != nil {
+		state["error"] = fmt.Errorf("Error creating temporary file for floppy: %s", err)
+		return multistep.ActionHalt
+	}
+	defer floppyF.Close()
+
+	log.Printf("Floppy path: %s", floppyF.Name())
+
+	// Set the size of the file to be a floppy sized
+	if err := floppyF.Truncate(1440 * 1024); err != nil {
+		state["error"] = fmt.Errorf("Error creating floppy: %s", err)
+		return multistep.ActionHalt
+	}
+
+	// BlockDevice backed by the file for our filesystem
+	log.Println("Initializing block device backed by temporary file")
+	device, err := fs.NewFileDisk(floppyF)
+	if err != nil {
+		state["error"] = fmt.Errorf("Error creating floppy: %s", err)
+		return multistep.ActionHalt
+	}
+
+	// Format the block device so it contains a valid FAT filesystem
+	log.Println("Formatting the block device with a FAT filesystem...")
+	formatConfig := &fat.SuperFloppyConfig{
+		FATType: fat.FAT12,
+		Label:   "packer",
+		OEMName: "packer",
+	}
+	if fat.FormatSuperFloppy(device, formatConfig); err != nil {
+		state["error"] = fmt.Errorf("Error creating floppy: %s", err)
+		return multistep.ActionHalt
+	}
+
+	// The actual FAT filesystem
+	log.Println("Initializing FAT filesystem on block device")
+	fatFs, err := fat.New(device)
+	if err != nil {
+		state["error"] = fmt.Errorf("Error creating floppy: %s", err)
+		return multistep.ActionHalt
+	}
+
+	// Get the root directory to the filesystem
+	log.Println("Reading the root directory from the filesystem")
+	rootDir, err := fatFs.RootDir()
+	if err != nil {
+		state["error"] = fmt.Errorf("Error creating floppy: %s", err)
+		return multistep.ActionHalt
+	}
+
+	// Go over each file and copy it.
+	for _, filename := range s.Files {
+		ui.Message(fmt.Sprintf("Copying: %s", filepath.Base(filename)))
+		if s.addSingleFile(rootDir, filename); err != nil {
+			state["error"] = fmt.Errorf("Error adding file to floppy: %s", err)
+			return multistep.ActionHalt
+		}
+	}
+
+	// Set the path to the floppy so it can be used later
+	state["floppy_path"] = floppyF.Name()
+
+	return multistep.ActionHalt
+}
+
+func (s *StepCreateFloppy) Cleanup(map[string]interface{}) {
+}
+
+func (s *StepCreateFloppy) addSingleFile(dir fs.Directory, src string) error {
+	log.Printf("Adding file to floppy: %s", src)
+
+	inputF, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer inputF.Close()
+
+	entry, err := dir.AddFile(filepath.Base(src))
+	if err != nil {
+		return err
+	}
+
+	fatFile, err := entry.File()
+	if err != nil {
+		return err
+	}
+
+	if _, err := io.Copy(fatFile, inputF); err != nil {
+		return err
+	}
+
+	return nil
+}