unistack-org/cloudinit
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fix(systemd): unmask runtime units when mask=False

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This commit is contained in:
Jonathan Boulle 2014-06-03 16:49:26 -07:00
parent 00ee047753
commit a6aa9f82b8
4 changed files with 155 additions and 22 deletions
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9
initialize/config.go
View File

@ -230,7 +230,7 @@ func Apply(cfg CloudConfig, env *Environment) error {
commands := make(map[string]string, 0)
reload := false
for _, unit := range cfg.Coreos.Units {
dst := system.UnitDestination(&unit, env.Root())
dst := unit.Destination(env.Root())
if unit.Content != "" {
log.Printf("Writing unit %s to filesystem at path %s", unit.Name, dst)
if err := system.PlaceUnit(&unit, dst); err != nil {
@ -242,7 +242,12 @@ func Apply(cfg CloudConfig, env *Environment) error {
if unit.Mask {
log.Printf("Masking unit file %s", unit.Name)
if err := system.MaskUnit(unit.Name, env.Root()); err != nil {
if err := system.MaskUnit(&unit, env.Root()); err != nil {
return err
}
} else if unit.Runtime {
log.Printf("Ensuring runtime unit file %s is unmasked", unit.Name)
if err := system.UnmaskUnit(&unit, env.Root()); err != nil {
return err
}
}

4
initialize/etcd_test.go
View File

@ -79,7 +79,7 @@ func TestEtcdEnvironmentWrittenToDisk(t *testing.T) {
}
u := uu[0]
dst := system.UnitDestination(&u, dir)
dst := u.Destination(dir)
os.Stderr.WriteString("writing to " + dir + "\n")
if err := system.PlaceUnit(&u, dst); err != nil {
t.Fatalf("Writing of EtcdEnvironment failed: %v", err)
@ -134,7 +134,7 @@ func TestEtcdEnvironmentWrittenToDiskDefaultToMachineID(t *testing.T) {
}
u := uu[0]
dst := system.UnitDestination(&u, dir)
dst := u.Destination(dir)
os.Stderr.WriteString("writing to " + dir + "\n")
if err := system.PlaceUnit(&u, dst); err != nil {
t.Fatalf("Writing of EtcdEnvironment failed: %v", err)

51
system/systemd.go
View File

@ -51,10 +51,10 @@ func (u *Unit) Group() (group string) {
type Script []byte
// UnitDestination builds the appropriate absolute file path for
// the given Unit. The root argument indicates the effective base
// Destination builds the appropriate absolute file path for
// the Unit. The root argument indicates the effective base
// directory of the system (similar to a chroot).
func UnitDestination(u *Unit, root string) string {
func (u *Unit) Destination(root string) string {
dir := "etc"
if u.Runtime {
dir = "run"
@ -179,12 +179,12 @@ func MachineID(root string) string {
return id
}
// MaskUnit masks a Unit by the given name by symlinking its unit file (in
// /etc/systemd/system) to /dev/null, analogous to `systemctl mask`
// MaskUnit masks the given Unit by symlinking its unit file to
// /dev/null, analogous to `systemctl mask`.
// N.B.: Unlike `systemctl mask`, this function will *remove any existing unit
// file* in /etc/systemd/system, to ensure that the mask will succeed.
func MaskUnit(unit string, root string) error {
masked := path.Join(root, "etc", "systemd", "system", unit)
// file at the location*, to ensure that the mask will succeed.
func MaskUnit(unit *Unit, root string) error {
masked := unit.Destination(root)
if _, err := os.Stat(masked); os.IsNotExist(err) {
if err := os.MkdirAll(path.Dir(masked), os.FileMode(0755)); err != nil {
return err
@ -194,3 +194,38 @@ func MaskUnit(unit string, root string) error {
}
return os.Symlink("/dev/null", masked)
}
// UnmaskUnit is analogous to systemd's unit_file_unmask. If the file
// associated with the given Unit is empty or appears to be a symlink to
// /dev/null, it is removed.
func UnmaskUnit(unit *Unit, root string) error {
masked := unit.Destination(root)
ne, err := nullOrEmpty(masked)
if os.IsNotExist(err) {
return nil
} else if err != nil {
return err
}
if !ne {
log.Printf("%s is not null or empty, refusing to unmask", masked)
return nil
}
return os.Remove(masked)
}
// nullOrEmpty checks whether a given path appears to be an empty regular file
// or a symlink to /dev/null
func nullOrEmpty(path string) (bool, error) {
fi, err := os.Stat(path)
if err != nil {
return false, err
}
m := fi.Mode()
if m.IsRegular() && fi.Size() <= 0 {
return true, nil
}
if m&os.ModeCharDevice > 0 {
return true, nil
}
return false, nil
}

113
system/systemd_test.go
View File

@ -25,10 +25,10 @@ Address=10.209.171.177/19
}
defer os.RemoveAll(dir)
dst := UnitDestination(&u, dir)
dst := u.Destination(dir)
expectDst := path.Join(dir, "run", "systemd", "network", "50-eth0.network")
if dst != expectDst {
t.Fatalf("UnitDestination returned %s, expected %s", dst, expectDst)
t.Fatalf("unit.Destination returned %s, expected %s", dst, expectDst)
}
if err := PlaceUnit(&u, dst); err != nil {
@ -69,18 +69,18 @@ func TestUnitDestination(t *testing.T) {
DropIn: false,
}
dst := UnitDestination(&u, dir)
dst := u.Destination(dir)
expectDst := path.Join(dir, "etc", "systemd", "system", "foobar.service")
if dst != expectDst {
t.Errorf("UnitDestination returned %s, expected %s", dst, expectDst)
t.Errorf("unit.Destination returned %s, expected %s", dst, expectDst)
}
u.DropIn = true
dst = UnitDestination(&u, dir)
dst = u.Destination(dir)
expectDst = path.Join(dir, "etc", "systemd", "system", "foobar.service.d", cloudConfigDropIn)
if dst != expectDst {
t.Errorf("UnitDestination returned %s, expected %s", dst, expectDst)
t.Errorf("unit.Destination returned %s, expected %s", dst, expectDst)
}
}
@ -100,10 +100,10 @@ Where=/media/state
}
defer os.RemoveAll(dir)
dst := UnitDestination(&u, dir)
dst := u.Destination(dir)
expectDst := path.Join(dir, "etc", "systemd", "system", "media-state.mount")
if dst != expectDst {
t.Fatalf("UnitDestination returned %s, expected %s", dst, expectDst)
t.Fatalf("unit.Destination returned %s, expected %s", dst, expectDst)
}
if err := PlaceUnit(&u, dst); err != nil {
@ -156,7 +156,8 @@ func TestMaskUnit(t *testing.T) {
defer os.RemoveAll(dir)
// Ensure mask works with units that do not currently exist
if err := MaskUnit("foo.service", dir); err != nil {
uf := &Unit{Name: "foo.service"}
if err := MaskUnit(uf, dir); err != nil {
t.Fatalf("Unable to mask new unit: %v", err)
}
fooPath := path.Join(dir, "etc", "systemd", "system", "foo.service")
@ -169,11 +170,12 @@ func TestMaskUnit(t *testing.T) {
}
// Ensure mask works with unit files that already exist
ub := &Unit{Name: "bar.service"}
barPath := path.Join(dir, "etc", "systemd", "system", "bar.service")
if _, err := os.Create(barPath); err != nil {
t.Fatalf("Error creating new unit file: %v", err)
}
if err := MaskUnit("bar.service", dir); err != nil {
if err := MaskUnit(ub, dir); err != nil {
t.Fatalf("Unable to mask existing unit: %v", err)
}
barTgt, err := os.Readlink(barPath)
@ -184,3 +186,94 @@ func TestMaskUnit(t *testing.T) {
t.Fatalf("unit not masked, got unit target", barTgt)
}
}
func TestUnmaskUnit(t *testing.T) {
dir, err := ioutil.TempDir(os.TempDir(), "coreos-cloudinit-")
if err != nil {
t.Fatalf("Unable to create tempdir: %v", err)
}
defer os.RemoveAll(dir)
nilUnit := &Unit{Name: "null.service"}
if err := UnmaskUnit(nilUnit, dir); err != nil {
t.Errorf("unexpected error from unmasking nonexistent unit: %v", err)
}
uf := &Unit{Name: "foo.service", Content: "[Service]\nExecStart=/bin/true"}
dst := uf.Destination(dir)
if err := os.MkdirAll(path.Dir(dst), os.FileMode(0755)); err != nil {
t.Fatalf("Unable to create unit directory: %v", err)
}
if _, err := os.Create(dst); err != nil {
t.Fatalf("Unable to write unit file: %v", err)
}
if err := ioutil.WriteFile(dst, []byte(uf.Content), 700); err != nil {
t.Fatalf("Unable to write unit file: %v", err)
}
if err := UnmaskUnit(uf, dir); err != nil {
t.Errorf("unmask of non-empty unit returned unexpected error: %v", err)
}
got, _ := ioutil.ReadFile(dst)
if string(got) != uf.Content {
t.Errorf("unmask of non-empty unit mutated unit contents unexpectedly")
}
ub := &Unit{Name: "bar.service"}
dst = ub.Destination(dir)
if err := os.Symlink("/dev/null", dst); err != nil {
t.Fatalf("Unable to create masked unit: %v", err)
}
if err := UnmaskUnit(ub, dir); err != nil {
t.Errorf("unmask of unit returned unexpected error: %v", err)
}
if _, err := os.Stat(dst); !os.IsNotExist(err) {
t.Errorf("expected %s to not exist after unmask, but got err: %s", err)
}
}
func TestNullOrEmpty(t *testing.T) {
dir, err := ioutil.TempDir(os.TempDir(), "coreos-cloudinit-")
if err != nil {
t.Fatalf("Unable to create tempdir: %v", err)
}
defer os.RemoveAll(dir)
non := path.Join(dir, "does_not_exist")
ne, err := nullOrEmpty(non)
if !os.IsNotExist(err) {
t.Errorf("nullOrEmpty on nonexistent file returned bad error: %v", err)
}
if ne {
t.Errorf("nullOrEmpty returned true unxpectedly")
}
regEmpty := path.Join(dir, "regular_empty_file")
_, err = os.Create(regEmpty)
if err != nil {
t.Fatalf("Unable to create tempfile: %v", err)
}
gotNe, gotErr := nullOrEmpty(regEmpty)
if !gotNe || gotErr != nil {
t.Errorf("nullOrEmpty of regular empty file returned %t, %v - want true, nil", gotNe, gotErr)
}
reg := path.Join(dir, "regular_file")
if err := ioutil.WriteFile(reg, []byte("asdf"), 700); err != nil {
t.Fatalf("Unable to create tempfile: %v", err)
}
gotNe, gotErr = nullOrEmpty(reg)
if gotNe || gotErr != nil {
t.Errorf("nullOrEmpty of regular file returned %t, %v - want false, nil", gotNe, gotErr)
}
null := path.Join(dir, "null")
if err := os.Symlink(os.DevNull, null); err != nil {
t.Fatalf("Unable to create /dev/null link: %s", err)
}
gotNe, gotErr = nullOrEmpty(null)
if !gotNe || gotErr != nil {
t.Errorf("nullOrEmpty of null symlink returned %t, %v - want true, nil", gotNe, gotErr)
}
}