interfaces,overlord: support unversioned data

interfaces/apparmor/template.go

@@ -233,13 +233,15 @@ var defaultTemplate = []byte(`
 
   # Writable home area for this version.
   owner @{HOME}/snap/@{SNAP_NAME}/@{SNAP_REVISION}/** wl,
+  owner @{HOME}/snap/@{SNAP_NAME}/common/** wl,
 
   # Read-only system area for other versions
   /var/snap/@{SNAP_NAME}/   r,
   /var/snap/@{SNAP_NAME}/** mrkix,
 
   # Writable system area only for this version
   /var/snap/@{SNAP_NAME}/@{SNAP_REVISION}/** wl,
+  /var/snap/@{SNAP_NAME}/common/** wl,
 
   # The ubuntu-core-launcher creates an app-specific private restricted /tmp
   # and will fail to launch the app if something goes wrong. As such, we can

overlord/snapstate/backend.go

@@ -42,6 +42,7 @@ type managerBackend interface {
 	UnlinkSnap(info *snap.Info, meter progress.Meter) error
 	RemoveSnapFiles(s snap.PlaceInfo, meter progress.Meter) error
 	RemoveSnapData(info *snap.Info) error
+	RemoveSnapCommonData(info *snap.Info) error
 
 	// testing helpers
 	Candidate(sideInfo *snap.SideInfo)
@@ -119,3 +120,7 @@ func (b *defaultBackend) RemoveSnapFiles(s snap.PlaceInfo, meter progress.Meter)
 func (b *defaultBackend) RemoveSnapData(info *snap.Info) error {
 	return snappy.RemoveSnapData(info)
 }
+
+func (b *defaultBackend) RemoveSnapCommonData(info *snap.Info) error {
+	return snappy.RemoveSnapCommonData(info)
+}

overlord/snapstate/backend_test.go

@@ -206,6 +206,14 @@ func (f *fakeSnappyBackend) RemoveSnapData(info *snap.Info) error {
 	return nil
 }
 
+func (f *fakeSnappyBackend) RemoveSnapCommonData(info *snap.Info) error {
+	f.ops = append(f.ops, fakeOp{
+		op:   "remove-snap-common-data",
+		name: info.MountDir(),
+	})
+	return nil
+}
+
 func (f *fakeSnappyBackend) Candidate(sideInfo *snap.SideInfo) {
 	var sinfo snap.SideInfo
 	if sideInfo != nil {

overlord/snapstate/snapmgr.go

@@ -276,7 +276,7 @@ func (m *SnapManager) doUnlinkSnap(t *state.Task, _ *tomb.Tomb) error {
 
 func (m *SnapManager) doClearSnapData(t *state.Task, _ *tomb.Tomb) error {
 	t.State().Lock()
-	ss, err := TaskSnapSetup(t)
+	ss, snapst, err := snapSetupAndState(t)
 	t.State().Unlock()
 	if err != nil {
 		return err
@@ -289,7 +289,18 @@ func (m *SnapManager) doClearSnapData(t *state.Task, _ *tomb.Tomb) error {
 		return err
 	}
 
-	return m.backend.RemoveSnapData(info)
+	if err = m.backend.RemoveSnapData(info); err != nil {
+		return err
+	}
+
+	// Only remove data common between versions if this is the last version
+	if len(snapst.Sequence) == 1 {
+		if err = m.backend.RemoveSnapCommonData(info); err != nil {
+			return err
+		}
+	}
+
+	return nil
 }
 
 func (m *SnapManager) doDiscardSnap(t *state.Task, _ *tomb.Tomb) error {

overlord/snapstate/snapmgr_test.go

@@ -927,7 +927,7 @@ func (s *snapmgrTestSuite) TestRemoveIntegration(c *C) {
 	s.settle()
 	s.state.Lock()
 
-	c.Assert(s.fakeBackend.ops, HasLen, 6)
+	c.Assert(s.fakeBackend.ops, HasLen, 7)
 	expected := []fakeOp{
 		fakeOp{
 			op:     "can-remove",
@@ -947,6 +947,10 @@ func (s *snapmgrTestSuite) TestRemoveIntegration(c *C) {
 			op:   "remove-snap-data",
 			name: "/snap/some-snap/7",
 		},
+		fakeOp{
+			op:   "remove-snap-common-data",
+			name: "/snap/some-snap/7",
+		},
 		fakeOp{
 			op:   "remove-snap-files",
 			name: "/snap/some-snap/7",
@@ -1018,7 +1022,7 @@ func (s *snapmgrTestSuite) TestRemoveWithManyRevisionsIntegration(c *C) {
 	s.settle()
 	s.state.Lock()
 
-	c.Assert(s.fakeBackend.ops, HasLen, 10)
+	c.Assert(s.fakeBackend.ops, HasLen, 11)
 	expected := []fakeOp{
 		{
 			op:     "can-remove",
@@ -1054,6 +1058,10 @@ func (s *snapmgrTestSuite) TestRemoveWithManyRevisionsIntegration(c *C) {
 			op:   "remove-snap-data",
 			name: "/snap/some-snap/5",
 		},
+		{
+			op:   "remove-snap-common-data",
+			name: "/snap/some-snap/5",
+		},
 		{
 			op:   "remove-snap-files",
 			name: "/snap/some-snap/5",

snap/info.go

@@ -45,8 +45,14 @@ type PlaceInfo interface {
 	// DataDir returns the data directory of the snap.
 	DataDir() string
 
+	// CommonDataDir returns the data directory common across revisions of the snap.
+	CommonDataDir() string
+
 	// DataHomeDir returns the per user data directory of the snap.
 	DataHomeDir() string
+
+	// CommonDataHomeDir returns the per user data directory common across revisions of the snap.
+	CommonDataHomeDir() string
 }
 
 // MinimalPlaceInfo returns a PlaceInfo with just the location information for a snap of the given name and revision.
@@ -157,11 +163,21 @@ func (s *Info) DataDir() string {
 	return filepath.Join(dirs.SnapDataDir, s.Name(), s.strRevno())
 }
 
+// CommonDataDir returns the data directory common across revisions of the snap.
+func (s *Info) CommonDataDir() string {
+	return filepath.Join(dirs.SnapDataDir, s.Name(), "common")
+}
+
 // DataHomeDir returns the per user data directory of the snap.
 func (s *Info) DataHomeDir() string {
 	return filepath.Join(dirs.SnapDataHomeGlob, s.Name(), s.strRevno())
 }
 
+// CommonDataHomeDir returns the per user data directory common across revisions of the snap.
+func (s *Info) CommonDataHomeDir() string {
+	return filepath.Join(dirs.SnapDataHomeGlob, s.Name(), "common")
+}
+
 // sanity check that Info is a PlacInfo
 var _ PlaceInfo = (*Info)(nil)
 

snappy/binaries_test.go

@@ -36,14 +36,14 @@ const expectedWrapper = `#!/bin/sh
 set -e
 
 # snap info
-export SNAP="/snap/pastebinit/44/"
-export SNAP_DATA="/var/snap/pastebinit/44/"
+export SNAP="/snap/pastebinit/44"
+export SNAP_DATA="/var/snap/pastebinit/44"
 export SNAP_NAME="pastebinit"
 export SNAP_VERSION="1.4.0.0.1"
 export SNAP_REVISION="44"
 export SNAP_ARCH="%[1]s"
 export SNAP_LIBRARY_PATH="/var/lib/snapd/lib/gl:"
-export SNAP_USER_DATA="$HOME/snap/pastebinit/44/"
+export SNAP_USER_DATA="$HOME/snap/pastebinit/44"
 
 if [ ! -d "$SNAP_USER_DATA" ]; then
    mkdir -p "$SNAP_USER_DATA"
@@ -57,7 +57,7 @@ ubuntu-core-launcher snap.pastebinit.pastebinit snap.pastebinit.pastebinit /snap
 `
 
 func (s *SnapTestSuite) TestSnappyGenerateSnapBinaryWrapper(c *C) {
-	pkgPath := "/snap/pastebinit/44/"
+	pkgPath := "/snap/pastebinit/44"
 	info := &snap.Info{}
 	info.SuggestedName = "pastebinit"
 	info.Version = "1.4.0.0.1"
@@ -76,7 +76,7 @@ func (s *SnapTestSuite) TestSnappyGenerateSnapBinaryWrapper(c *C) {
 }
 
 func (s *SnapTestSuite) TestSnappyGenerateSnapBinaryWrapperIllegalChars(c *C) {
-	pkgPath := "/snap/pastebinit/44/"
+	pkgPath := "/snap/pastebinit/44"
 	info := &snap.Info{}
 	info.SuggestedName = "pastebinit"
 	info.Version = "1.4.0.0.1"
@@ -91,12 +91,12 @@ func (s *SnapTestSuite) TestSnappyGenerateSnapBinaryWrapperIllegalChars(c *C) {
 
 func (s *SnapTestSuite) TestSnappyBinPathForBinaryNoExec(c *C) {
 	binary := &snap.AppInfo{Name: "pastebinit", Command: "bin/pastebinit"}
-	pkgPath := "/snap/pastebinit/44/"
+	pkgPath := "/snap/pastebinit/44"
 	c.Assert(binPathForBinary(pkgPath, binary), Equals, "/snap/pastebinit/44/bin/pastebinit")
 }
 
 func (s *SnapTestSuite) TestSnappyBinPathForBinaryWithExec(c *C) {
 	binary := &snap.AppInfo{Name: "pastebinit", Command: "bin/random-pastebin"}
-	pkgPath := "/snap/pastebinit/44/"
+	pkgPath := "/snap/pastebinit/44"
 	c.Assert(binPathForBinary(pkgPath, binary), Equals, "/snap/pastebinit/44/bin/random-pastebin")
 }

snappy/install_test.go

@@ -124,7 +124,16 @@ func (s *SnapTestSuite) TestClickInstallGCSimple(c *C) {
 	// gc should no longer leave one more data than app
 	globs, err = filepath.Glob(filepath.Join(dirs.SnapDataDir, "foo", "*"))
 	c.Check(err, IsNil)
-	c.Check(globs, HasLen, 2+1) // +1 for "current"
+	c.Check(globs, HasLen, 2+1+1) // +1 for "current", +1 for common
+
+	// ensure common data is actually present, and it isn't the old version
+	commonFound := false
+	for _, glob := range globs {
+		if filepath.Base(glob) == "common" {
+			commonFound = true
+		}
+	}
+	c.Check(commonFound, Equals, true)
 }
 
 // check that if flags does not include DoInstallGC, no gc is done
@@ -137,7 +146,16 @@ func (s *SnapTestSuite) TestClickInstallGCSuppressed(c *C) {
 
 	globs, err = filepath.Glob(filepath.Join(dirs.SnapDataDir, "foo", "*"))
 	c.Check(err, IsNil)
-	c.Check(globs, HasLen, 3+1) // +1 for "current"
+	c.Check(globs, HasLen, 3+1+1) // +1 for "current", +1 for common
+
+	// ensure common data is actually present
+	commonFound := false
+	for _, glob := range globs {
+		if filepath.Base(glob) == "common" {
+			commonFound = true
+		}
+	}
+	c.Check(commonFound, Equals, true)
 }
 
 func (s *SnapTestSuite) TestInstallAppTwiceFails(c *C) {

snappy/overlord.go

@@ -178,13 +178,17 @@ func UndoSetupSnap(s snap.PlaceInfo, meter progress.Meter) {
 }
 
 func CopyData(newSnap, oldSnap *snap.Info, flags InstallFlags, meter progress.Meter) error {
-	dataDir := newSnap.DataDir()
-
 	// deal with the old data or
 	// otherwise just create a empty data dir
 
+	// Make sure the common data directory exists, even if this isn't a new
+	// install.
+	if err := os.MkdirAll(newSnap.CommonDataDir(), 0755); err != nil {
+		return err
+	}
+
 	if oldSnap == nil {
-		return os.MkdirAll(dataDir, 0755)
+		return os.MkdirAll(newSnap.DataDir(), 0755)
 	}
 
 	return copySnapData(oldSnap, newSnap)

snappy/overlord_test.go

@@ -73,7 +73,7 @@ func (s *SnapTestSuite) TestLocalSnapInstall(c *C) string {
 	c.Check(snapEntries, DeepEquals, []string{"0", "current"})
 
 	snapDataEntries := listDir(c, filepath.Join(dirs.SnapDataDir, fooComposedName))
-	c.Check(snapDataEntries, DeepEquals, []string{"0", "current"})
+	c.Check(snapDataEntries, DeepEquals, []string{"0", "common", "current"})
 
 	return snapPath
 }
@@ -98,7 +98,7 @@ func (s *SnapTestSuite) TestLocalSnapInstallWithBlessedMetadata(c *C) {
 	c.Check(snapEntries, DeepEquals, []string{"40", "current"})
 
 	snapDataEntries := listDir(c, filepath.Join(dirs.SnapDataDir, fooComposedName))
-	c.Check(snapDataEntries, DeepEquals, []string{"40", "current"})
+	c.Check(snapDataEntries, DeepEquals, []string{"40", "common", "current"})
 }
 
 func (s *SnapTestSuite) TestLocalSnapInstallWithBlessedMetadataOverridingName(c *C) {
@@ -401,6 +401,9 @@ func (s *SnapTestSuite) TestCopyData(c *C) {
 	homeData := filepath.Join(homeDir, appDir, "10")
 	err := os.MkdirAll(homeData, 0755)
 	c.Assert(err, IsNil)
+	homeCommonData := filepath.Join(homeDir, appDir, "common")
+	err = os.MkdirAll(homeCommonData, 0755)
+	c.Assert(err, IsNil)
 
 	snapYamlContent := `name: foo
 `
@@ -412,8 +415,13 @@ func (s *SnapTestSuite) TestCopyData(c *C) {
 	canaryDataFile := filepath.Join(dirs.SnapDataDir, appDir, "10", "canary.txt")
 	err = ioutil.WriteFile(canaryDataFile, canaryData, 0644)
 	c.Assert(err, IsNil)
+	canaryDataFile = filepath.Join(dirs.SnapDataDir, appDir, "common", "canary.common")
+	err = ioutil.WriteFile(canaryDataFile, canaryData, 0644)
+	c.Assert(err, IsNil)
 	err = ioutil.WriteFile(filepath.Join(homeData, "canary.home"), canaryData, 0644)
 	c.Assert(err, IsNil)
+	err = ioutil.WriteFile(filepath.Join(homeCommonData, "canary.common_home"), canaryData, 0644)
+	c.Assert(err, IsNil)
 
 	snapPath = makeTestSnapPackage(c, snapYamlContent+"version: 2.0")
 	_, err = (&Overlord{}).InstallWithSideInfo(snapPath, fooSI20, AllowUnauthenticated, nil)
@@ -423,8 +431,20 @@ func (s *SnapTestSuite) TestCopyData(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(content, DeepEquals, canaryData)
 
-	newHomeDataCanaryFile := filepath.Join(homeDir, appDir, "20", "canary.home")
-	content, err = ioutil.ReadFile(newHomeDataCanaryFile)
+	// ensure common data file is still there (even though it didn't get copied)
+	newCanaryDataFile = filepath.Join(dirs.SnapDataDir, appDir, "common", "canary.common")
+	content, err = ioutil.ReadFile(newCanaryDataFile)
+	c.Assert(err, IsNil)
+	c.Assert(content, DeepEquals, canaryData)
+
+	newCanaryDataFile = filepath.Join(homeDir, appDir, "20", "canary.home")
+	content, err = ioutil.ReadFile(newCanaryDataFile)
+	c.Assert(err, IsNil)
+	c.Assert(content, DeepEquals, canaryData)
+
+	// ensure home common data file is still there (even though it didn't get copied)
+	newCanaryDataFile = filepath.Join(homeDir, appDir, "common", "canary.common_home")
+	content, err = ioutil.ReadFile(newCanaryDataFile)
 	c.Assert(err, IsNil)
 	c.Assert(content, DeepEquals, canaryData)
 }
@@ -445,15 +465,21 @@ func (s *SnapTestSuite) TestCopyDataNoUserHomes(c *C) {
 	canaryDataFile := filepath.Join(snap.DataDir(), "canary.txt")
 	err = ioutil.WriteFile(canaryDataFile, []byte(""), 0644)
 	c.Assert(err, IsNil)
+	canaryDataFile = filepath.Join(snap.CommonDataDir(), "canary.common")
+	err = ioutil.WriteFile(canaryDataFile, []byte(""), 0644)
+	c.Assert(err, IsNil)
 
 	snapPath = makeTestSnapPackage(c, snapYamlContent+"version: 2.0")
 	snap2, err := (&Overlord{}).InstallWithSideInfo(snapPath, fooSI20, AllowUnauthenticated, nil)
 	c.Assert(err, IsNil)
 	_, err = os.Stat(filepath.Join(snap2.DataDir(), "canary.txt"))
 	c.Assert(err, IsNil)
+	_, err = os.Stat(filepath.Join(snap2.CommonDataDir(), "canary.common"))
+	c.Assert(err, IsNil)
 
 	// sanity atm
 	c.Check(snap.DataDir(), Not(Equals), snap2.DataDir())
+	c.Check(snap.CommonDataDir(), Equals, snap2.CommonDataDir())
 }
 
 func (s *SnapTestSuite) TestSnappyHandleBinariesOnUpgrade(c *C) {
@@ -466,7 +492,7 @@ apps:
 	_, err := (&Overlord{}).InstallWithSideInfo(snapPath, fooSI10, AllowUnauthenticated, nil)
 	c.Assert(err, IsNil)
 
-	// ensure that the binary wrapper file go generated with the right
+	// ensure that the binary wrapper file got generated with the right
 	// path
 	oldSnapBin := filepath.Join(dirs.SnapSnapsDir[len(dirs.GlobalRootDir):], "foo", "10", "bin", "bar")
 	binaryWrapper := filepath.Join(dirs.SnapBinariesDir, "foo.bar")