!7 syscontainer: internal change

Merge pull request !7 from zhangsong234/master

hooks/syscontainer-hooks/prestart.go

@@ -96,6 +96,7 @@ func AddDevices(state *configs.HookState, hookConfig *hconfig.ContainerHookConfi
 		// re-calc the dest path of device.
 		resolvDev := calcPathForDevice(state.Root, dev)
 		device, err := libdevice.ParseDevice(resolvDev)
+		device.Root = state.Root
 		if err != nil {
 			logrus.Errorf("[device-hook] Add device (%s), parse device failed: %v", resolvDev, err)
 			return err

libdevice/container_work.go

@@ -237,6 +237,12 @@ func doAddDevice(pipe *os.File) error {
 	if err := MknodDevice(device.Path, device); err != nil {
 		return fmt.Errorf("Current OS kernel do not support mknod in container user namespace for root, err: %s", err)
 	}
+	if device.Type == "b" {
+		// fdisk: add device soft link to /sys/block
+		if err := AddDeviceToSysBlock(device); err != nil {
+			return fmt.Errorf("Add device to /sys/block failed: %s", device, err)
+		}
+	}
 	return nil
 }
 
@@ -255,7 +261,12 @@ func doRemoveDevice(pipe *os.File) error {
 	if _, err := DeviceFromPath(device.Path, ""); err != nil {
 		return err
 	}
-
+	if device.Type == "b" {
+		// fdisk: remove device symlink in /sys/block
+		if err := RemoveDeviceFromSysBlock(device.Path); err != nil {
+			return err
+		}
+	}
 	// need strict check here?
 	return os.Remove(device.Path)
 }

libdevice/devices_unix.go

@@ -18,20 +18,26 @@ package libdevice
 import (
 	"errors"
 	"fmt"
+	"github.com/mrunalp/fileutils"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/sys/unix"
+	"isula.org/syscontainer-tools/types"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strings"
 	"syscall"
-
-	"isula.org/syscontainer-tools/types"
-
-	"github.com/sirupsen/logrus"
 )
 
 var (
 	// ErrNotADevice not a device error
 	ErrNotADevice = errors.New("not a device")
+	// MountSourcePath mount source path
+	MountSourcePath = "/mnt/sys/block"
+	// DevBlockPath device block path
+	DevBlockPath = "/sys/dev/block"
+	// MountDestPath mount dest path
+	MountDestPath = "/sys/block"
 )
 
 // Testing dependencies
@@ -243,6 +249,92 @@ func MknodDevice(dest string, node *types.Device) error {
 	return syscall.Chown(dest, int(node.UID), int(node.GID))
 }
 
+// prepareSysBlockMount bind mount /mnt/sys/block to /sys/block
+func prepareSysBlockMount(root string) error {
+	if unix.Access(filepath.Join(root, MountDestPath), unix.W_OK) == nil {
+		return nil
+	}
+	if err := os.RemoveAll(filepath.Join(root, MountSourcePath)); err != nil {
+		return err
+	}
+	if err := fileutils.CopyDirectory(
+		filepath.Join(root, MountDestPath),
+		filepath.Join(root, MountSourcePath)); err != nil {
+		return err
+	}
+	if err := syscall.Mount(
+		filepath.Join(root, MountSourcePath),
+		filepath.Join(root, MountDestPath),
+		"",
+		syscall.MS_BIND|syscall.MS_REC, ""); err != nil {
+		return err
+	}
+	return nil
+}
+
+// AddDeviceToSysBlock add device to /sys/block in container
+func AddDeviceToSysBlock(node *types.Device) error {
+	if err := prepareSysBlockMount(node.Root); err != nil {
+		return err
+	}
+	devStr := fmt.Sprintf("%d:%d", node.Major, node.Minor)
+	linkPath := filepath.Join(DevBlockPath, devStr)
+	if _, err := os.Lstat(linkPath); os.IsNotExist(err) {
+		return err
+	}
+	realPath, err := os.Readlink(linkPath)
+	if err != nil {
+		return err
+	}
+	hostDeviceName := filepath.Base(realPath)
+	containerDeviceName := filepath.Base(node.Path)
+	if err := os.Chdir(filepath.Join(node.Root, MountSourcePath)); err != nil {
+		return err
+	}
+	if _, err := os.Lstat(containerDeviceName); err == nil {
+		if err := os.Remove(containerDeviceName); err != nil {
+			return err
+		}
+	}
+	destPath := strings.Replace(realPath, "../", "", 1)
+	if destPath == "" {
+		return nil
+	}
+	if err := os.Symlink(destPath, containerDeviceName); err != nil {
+		return err
+	}
+	if err := os.Chdir(filepath.Join(node.Root, "/dev")); err != nil {
+		return err
+	}
+	if hostDeviceName != containerDeviceName {
+		if _, err := os.Stat(hostDeviceName); os.IsNotExist(err) {
+			return os.Symlink(containerDeviceName, hostDeviceName)
+		}
+	}
+	return nil
+}
+
+// RemoveDeviceFromSysBlock remove device from /sys/block in container
+func RemoveDeviceFromSysBlock(path string) error {
+	containerDeviceName := filepath.Base(path)
+	linkPath := filepath.Join(MountDestPath, containerDeviceName)
+	realPath, err := os.Readlink(linkPath)
+	if err != nil {
+		return err
+	}
+	hostDeviceName := filepath.Base(realPath)
+	devPath := filepath.Join("/dev", hostDeviceName)
+	if _, err := os.Lstat(linkPath); err == nil {
+		if err := os.Remove(linkPath); err != nil {
+			return err
+		}
+	}
+	if hostDeviceName != containerDeviceName {
+		return os.Remove(devPath)
+	}
+	return nil
+}
+
 // SetDefaultPath set default path for device
 func SetDefaultPath(dev *types.Device) {
 	if dev.Path == "" {

types/device.go

@@ -72,6 +72,7 @@ type Device struct {
 	GID         uint32      // Group ID
 	Allow       bool        // Used to differ add or remove
 	Parent      string      // Parent device name(pathonhost)
+	Root        string      // Rootfs path, prestart hook needed.
 }
 
 // Qos is the device Qos structure