github.com/dkerwin/nomad@v0.3.3-0.20160525181927-74554135514b/client/allocdir/alloc_dir_linux.go (about)

     1  package allocdir
     2  
     3  import (
     4  	"fmt"
     5  	"os"
     6  	"path/filepath"
     7  	"syscall"
     8  
     9  	"github.com/hashicorp/go-multierror"
    10  )
    11  
    12  // Bind mounts the shared directory into the task directory. Must be root to
    13  // run.
    14  func (d *AllocDir) mountSharedDir(taskDir string) error {
    15  	if err := os.MkdirAll(taskDir, 0777); err != nil {
    16  		return err
    17  	}
    18  
    19  	return syscall.Mount(d.SharedDir, taskDir, "", syscall.MS_BIND, "")
    20  }
    21  
    22  func (d *AllocDir) unmountSharedDir(dir string) error {
    23  	return syscall.Unmount(dir, 0)
    24  }
    25  
    26  // MountSpecialDirs mounts the dev and proc file system from the host to the
    27  // chroot
    28  func (d *AllocDir) MountSpecialDirs(taskDir string) error {
    29  	// Mount dev
    30  	dev := filepath.Join(taskDir, "dev")
    31  	if !d.pathExists(dev) {
    32  		if err := os.MkdirAll(dev, 0777); err != nil {
    33  			return fmt.Errorf("Mkdir(%v) failed: %v", dev, err)
    34  		}
    35  
    36  		if err := syscall.Mount("none", dev, "devtmpfs", syscall.MS_RDONLY, ""); err != nil {
    37  			return fmt.Errorf("Couldn't mount /dev to %v: %v", dev, err)
    38  		}
    39  	}
    40  
    41  	// Mount proc
    42  	proc := filepath.Join(taskDir, "proc")
    43  	if !d.pathExists(proc) {
    44  		if err := os.MkdirAll(proc, 0777); err != nil {
    45  			return fmt.Errorf("Mkdir(%v) failed: %v", proc, err)
    46  		}
    47  
    48  		if err := syscall.Mount("none", proc, "proc", syscall.MS_RDONLY, ""); err != nil {
    49  			return fmt.Errorf("Couldn't mount /proc to %v: %v", proc, err)
    50  		}
    51  	}
    52  
    53  	return nil
    54  }
    55  
    56  // unmountSpecialDirs unmounts the dev and proc file system from the chroot
    57  func (d *AllocDir) unmountSpecialDirs(taskDir string) error {
    58  	errs := new(multierror.Error)
    59  	dev := filepath.Join(taskDir, "dev")
    60  	if d.pathExists(dev) {
    61  		if err := syscall.Unmount(dev, 0); err != nil {
    62  			errs = multierror.Append(errs, fmt.Errorf("Failed to unmount dev (%v): %v", dev, err))
    63  		} else if err := os.RemoveAll(dev); err != nil {
    64  			errs = multierror.Append(errs, fmt.Errorf("Failed to delete dev directory (%v): %v", dev, err))
    65  		}
    66  	}
    67  
    68  	// Unmount proc.
    69  	proc := filepath.Join(taskDir, "proc")
    70  	if d.pathExists(proc) {
    71  		if err := syscall.Unmount(proc, 0); err != nil {
    72  			errs = multierror.Append(errs, fmt.Errorf("Failed to unmount proc (%v): %v", proc, err))
    73  		} else if err := os.RemoveAll(proc); err != nil {
    74  			errs = multierror.Append(errs, fmt.Errorf("Failed to delete proc directory (%v): %v", dev, err))
    75  		}
    76  	}
    77  
    78  	return errs.ErrorOrNil()
    79  }