Make sure vmlinux and initrd file path are not hard coded

Author: praveenkumar

Makefile

@@ -20,3 +20,5 @@ build: $(BUILD_DIR) vendor
 	go build \
 			-installsuffix "static" \
 			-o $(BUILD_DIR)/docker-machine-driver-hyperkit
+	chmod +x $(BUILD_DIR)/docker-machine-driver-hyperkit
+	sudo mv $(BUILD_DIR)/docker-machine-driver-hyperkit /usr/local/bin/ && sudo chown root:wheel /usr/local/bin/docker-machine-driver-hyperkit && sudo chmod u+s /usr/local/bin/docker-machine-driver-hyperkit

pkg/hyperkit/driver.go

@@ -36,17 +36,25 @@ import (
 	hyperkit "github.com/moby/hyperkit/go"
 	"github.com/pkg/errors"
 	pkgdrivers "github.com/praveenkumar/docker-machine-driver-hyperkit/pkg/drivers"
+	"regexp"
+	"github.com/docker/machine/libmachine/mcnutils"
 )
 
 const (
 	isoFilename     = "boot2docker.iso"
+	isoMountPath    = "b2d-image"
 	pidFileName     = "hyperkit.pid"
 	machineFileName = "hyperkit.json"
 	permErr         = "%s needs to run with elevated permissions. " +
 		"Please run the following command, then try again: " +
 		"sudo chown root:wheel %s && sudo chmod u+s %s"
 )
 
+var (
+	kernelRegexp       = regexp.MustCompile(`(vmlinu[xz]|bzImage)[\d]*`)
+	kernelOptionRegexp = regexp.MustCompile(`(?:\t|\s{2})append\s+([[:print:]]+)`)
+)
+
 type Driver struct {
 	*drivers.BaseDriver
 	*pkgdrivers.CommonDriver
@@ -58,6 +66,10 @@ type Driver struct {
 	NFSShares      []string
 	NFSSharesRoot  string
 	UUID           string
+	BootKernel string
+	BootInitrd string
+	Initrd     string
+	Vmlinuz    string
 }
 
 func NewDriver(hostName, storePath string) *Driver {
@@ -169,8 +181,8 @@ func (d *Driver) Start() error {
 	}
 
 	// TODO: handle the rest of our settings.
-	h.Kernel = d.ResolveStorePath("bzimage")
-	h.Initrd = d.ResolveStorePath("initrd")
+	h.Kernel = d.ResolveStorePath(d.Vmlinuz)
+	h.Initrd =d.ResolveStorePath(d.Initrd)
 	h.VMNet = true
 	h.ISOImages = []string{d.ResolveStorePath(isoFilename)}
 	h.Console = hyperkit.ConsoleFile
@@ -233,19 +245,54 @@ func (d *Driver) Stop() error {
 }
 
 func (d *Driver) extractKernel(isoPath string) error {
-	for _, f := range []struct {
-		pathInIso string
-		destPath  string
-	}{
-		{"/boot/bzimage", "bzimage"},
-		{"/boot/initrd", "initrd"},
-		{"/isolinux/isolinux.cfg", "isolinux.cfg"},
-	} {
-		fullDestPath := d.ResolveStorePath(f.destPath)
-		if err := ExtractFile(isoPath, f.pathInIso, fullDestPath); err != nil {
-			return err
+	log.Debugf("Mounting %s", isoFilename)
+
+	volumeRootDir := d.ResolveStorePath(isoMountPath)
+	err := hdiutil("attach", d.ResolveStorePath(isoFilename), "-mountpoint", volumeRootDir)
+	if err != nil {
+		return err
+	}
+	defer func() error {
+		log.Debugf("Unmounting %s", isoFilename)
+		return hdiutil("detach", volumeRootDir)
+	}()
+
+	log.Debugf("Extracting Kernel Options...")
+	if err := d.extractKernelOptions(); err != nil {
+		return err
+	}
+
+	if d.BootKernel == "" && d.BootInitrd == "" {
+		filepath.Walk(volumeRootDir, func(path string, f os.FileInfo, err error) error {
+			if kernelRegexp.MatchString(path) {
+				d.BootKernel = path
+				_, d.Vmlinuz = filepath.Split(path)
+			}
+			if strings.Contains(path, "initrd") {
+				d.BootInitrd = path
+				_, d.Initrd = filepath.Split(path)
+			}
+			return nil
+		})
+	}
+	
+	if  d.BootKernel == "" || d.BootInitrd == "" {
+		err := fmt.Errorf("==== Can't extract Kernel and Ramdisk file ====")
+		return err
 		}
+
+	dest := d.ResolveStorePath(d.Vmlinuz)
+	log.Debugf("Extracting %s into %s", d.BootKernel, dest)
+	if err := mcnutils.CopyFile(d.BootKernel, dest); err != nil {
+		return err
+	}
+
+	dest = d.ResolveStorePath(d.Initrd)
+	log.Debugf("Extracting %s into %s", d.BootInitrd, dest)
+	if err := mcnutils.CopyFile(d.BootInitrd, dest); err != nil {
+		return err
 	}
+
 	return nil
 }
 
@@ -341,3 +388,28 @@ func (d *Driver) cleanupNfsExports() {
 		}
 	}
 }
+
+func (d *Driver) extractKernelOptions() error {
+	volumeRootDir := d.ResolveStorePath(isoMountPath)
+	if d.Cmdline == "" {
+		err := filepath.Walk(volumeRootDir, func(path string, f os.FileInfo, err error) error {
+			if strings.Contains(path, "isolinux.cfg") {
+				d.Cmdline, err = readLine(path)
+				if err != nil {
+					return err
+				}
+			}
+			return nil
+		})
+		if err != nil {
+			return err
+		}
+
+		if d.Cmdline == "" {
+			return errors.New("Not able to parse isolinux.cfg")
+		}
+	}
+
+	log.Debugf("Extracted Options %q", d.Cmdline)
+	return nil
+}

pkg/hyperkit/iso.go

@@ -20,6 +20,11 @@ import (
 	"time"
 	"errors"
 	"strings"
+	"os/exec"
+	"os"
+	"github.com/docker/machine/libmachine/log"
+	"bufio"
+	"fmt"
 )
 
 type RetriableError struct {
@@ -66,4 +71,36 @@ func RetryAfter(attempts int, callback func() error, d time.Duration) (err error
 		time.Sleep(d)
 	}
 	return m.ToError()
+}
+
+func hdiutil(args ...string) error {
+	cmd := exec.Command("hdiutil", args...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	log.Debugf("executing: %v %v", cmd, strings.Join(args, " "))
+
+	err := cmd.Run()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func readLine(path string) (string, error) {
+	inFile, err := os.Open(path)
+	if err != nil {
+		return "", err
+	}
+	defer inFile.Close()
+
+	scanner := bufio.NewScanner(inFile)
+	for scanner.Scan() {
+		if kernelOptionRegexp.Match(scanner.Bytes()) {
+			m := kernelOptionRegexp.FindSubmatch(scanner.Bytes())
+			return string(m[1]), nil
+		}
+	}
+	return "", fmt.Errorf("couldn't find kernel option from %s image", path)
 }