Merge #73

73: Check mountpoints exist on the host early r=sjoerdsimons a=obbardc

If a mountpoint doesn't exist on the host, the backend
will fail to mount it and results in an ugly error
from the backend:

    $ fakemachine -v /null
    qemu-system-x86_64: -virtfs local,mount_tag=virtfs-5,path=/null,security_model=none: cannot initialize fsdev 'virtfs-5': failed to open '/null': No such file or directory
    fakemachine: error starting kvm backend: <nil>

Check if a mountpoint exists before attempting to start
the backend.

Signed-off-by: Christopher Obbard <[email protected]>

Co-authored-by: Christopher Obbard <[email protected]>

machine.go

@@ -13,12 +13,13 @@ import (
 	"os/exec"
 	"path"
 	"path/filepath"
+	"regexp"
 	"runtime"
 	"strconv"
 	"strings"
 	"text/template"
 
-	"github.com/go-debos/fakemachine/cpio"
+	writerhelper "github.com/go-debos/fakemachine/cpio"
 )
 
 func mergedUsrSystem() bool {
@@ -578,6 +579,25 @@ func (m *Machine) startup(command string, extracontent [][2]string) (int, error)
 
 	os.Setenv("PATH", os.Getenv("PATH")+":/sbin:/usr/sbin")
 
+	/* Sanity check mountpoints */
+	for _, v := range m.mounts {
+		/* Check the directory exists on the host */
+		stat, err := os.Stat(v.hostDirectory)
+		if err != nil || !stat.IsDir() {
+			return -1, fmt.Errorf("Couldn't mount %s inside machine: expected a directory", v.hostDirectory)
+		}
+
+		/* Check for whitespace in the machine directory */
+		if regexp.MustCompile(`\s`).MatchString(v.machineDirectory) {
+			return -1, fmt.Errorf("Couldn't mount %s inside machine: machine directory (%s) contains whitespace", v.hostDirectory, v.machineDirectory)
+		}
+
+		/* Check for whitespace in the label */
+		if regexp.MustCompile(`\s`).MatchString(v.label) {
+			return -1, fmt.Errorf("Couldn't mount %s inside machine: label (%s) contains whitespace", v.hostDirectory, v.label)
+		}
+	}
+
 	tmpdir, err := ioutil.TempDir("", "fakemachine-")
 	if err != nil {
 		return -1, err

machine_test.go

@@ -185,3 +185,35 @@ func TestImageLabel(t *testing.T) {
 		t.Fatalf("Test for images in the machine failed failed with %d", exitcode)
 	}
 }
+
+func TestVolumes(t *testing.T) {
+	t.Parallel()
+	if InMachine() {
+		t.Log("Running in the machine")
+		return
+	}
+
+	/* Try to mount a non-existent file into the machine */
+	m := CreateMachine(t)
+	m.AddVolume("random_directory_never_exists")
+
+	exitcode, err := m.RunInMachineWithArgs([]string{"-test.run TestVolumes"})
+	require.Equal(t, exitcode, -1)
+	require.Error(t, err)
+
+	/* Try to mount a device file into the machine */
+	m = CreateMachine(t)
+	m.AddVolume("/dev/zero")
+
+	exitcode, err = m.RunInMachineWithArgs([]string{"-test.run TestVolumes"})
+	require.Equal(t, exitcode, -1)
+	require.Error(t, err)
+
+	/* Try to mount a volume with whitespace into the machine */
+	m = CreateMachine(t)
+	m.AddVolumeAt("/dev", "/dev ices")
+
+	exitcode, err = m.RunInMachineWithArgs([]string{"-test.run TestVolumes"})
+	require.Equal(t, exitcode, -1)
+	require.Error(t, err)
+}