open-nomad/client/allocdir/alloc_dir_linux.go

117 lines
3.1 KiB
Go

package allocdir
import (
"fmt"
"os"
"path/filepath"
"syscall"
"golang.org/x/sys/unix"
"github.com/hashicorp/go-multierror"
)
const (
// secretDirTmpfsSize is the size of the tmpfs per task in MBs
secretDirTmpfsSize = 1
)
// Bind mounts the shared directory into the task directory. Must be root to
// run.
func (d *AllocDir) mountSharedDir(taskDir string) error {
if err := os.MkdirAll(taskDir, 0777); err != nil {
return err
}
return syscall.Mount(d.SharedDir, taskDir, "", syscall.MS_BIND, "")
}
func (d *AllocDir) unmountSharedDir(dir string) error {
return syscall.Unmount(dir, 0)
}
// createSecretDir creates the secrets dir folder at the given path using a
// tmpfs
func (d *AllocDir) createSecretDir(dir string) error {
// Only mount the tmpfs if we are root
if unix.Geteuid() == 0 {
if err := os.MkdirAll(dir, 0777); err != nil {
return err
}
var flags uintptr
flags = syscall.MS_NOEXEC
options := fmt.Sprintf("size=%dm", secretDirTmpfsSize)
err := syscall.Mount("tmpfs", dir, "tmpfs", flags, options)
return os.NewSyscallError("mount", err)
}
return os.MkdirAll(dir, 0777)
}
// createSecretDir removes the secrets dir folder
func (d *AllocDir) removeSecretDir(dir string) error {
if unix.Geteuid() == 0 {
if err := syscall.Unmount(dir, 0); err != nil {
return os.NewSyscallError("unmount", err)
}
}
return os.RemoveAll(dir)
}
// MountSpecialDirs mounts the dev and proc file system from the host to the
// chroot
func (d *AllocDir) MountSpecialDirs(taskDir string) error {
// Mount dev
dev := filepath.Join(taskDir, "dev")
if !d.pathExists(dev) {
if err := os.MkdirAll(dev, 0777); err != nil {
return fmt.Errorf("Mkdir(%v) failed: %v", dev, err)
}
if err := syscall.Mount("none", dev, "devtmpfs", syscall.MS_RDONLY, ""); err != nil {
return fmt.Errorf("Couldn't mount /dev to %v: %v", dev, err)
}
}
// Mount proc
proc := filepath.Join(taskDir, "proc")
if !d.pathExists(proc) {
if err := os.MkdirAll(proc, 0777); err != nil {
return fmt.Errorf("Mkdir(%v) failed: %v", proc, err)
}
if err := syscall.Mount("none", proc, "proc", syscall.MS_RDONLY, ""); err != nil {
return fmt.Errorf("Couldn't mount /proc to %v: %v", proc, err)
}
}
return nil
}
// unmountSpecialDirs unmounts the dev and proc file system from the chroot
func (d *AllocDir) unmountSpecialDirs(taskDir string) error {
errs := new(multierror.Error)
dev := filepath.Join(taskDir, "dev")
if d.pathExists(dev) {
if err := syscall.Unmount(dev, 0); err != nil {
errs = multierror.Append(errs, fmt.Errorf("Failed to unmount dev (%v): %v", dev, err))
} else if err := os.RemoveAll(dev); err != nil {
errs = multierror.Append(errs, fmt.Errorf("Failed to delete dev directory (%v): %v", dev, err))
}
}
// Unmount proc.
proc := filepath.Join(taskDir, "proc")
if d.pathExists(proc) {
if err := syscall.Unmount(proc, 0); err != nil {
errs = multierror.Append(errs, fmt.Errorf("Failed to unmount proc (%v): %v", proc, err))
} else if err := os.RemoveAll(proc); err != nil {
errs = multierror.Append(errs, fmt.Errorf("Failed to delete proc directory (%v): %v", dev, err))
}
}
return errs.ErrorOrNil()
}