Move mount to core/mount

Signed-off-by: Derek McGowan <derek@mcg.dev>

core/mount/mount_linux_test.go

@@ -0,0 +1,245 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package mount
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"reflect"
+	"testing"
+
+	"github.com/containerd/continuity/testutil"
+	"golang.org/x/sys/unix"
+)
+
+func TestLongestCommonPrefix(t *testing.T) {
+	tcases := []struct {
+		in       []string
+		expected string
+	}{
+		{[]string{}, ""},
+		{[]string{"foo"}, "foo"},
+		{[]string{"foo", "bar"}, ""},
+		{[]string{"foo", "foo"}, "foo"},
+		{[]string{"foo", "foobar"}, "foo"},
+		{[]string{"foo", "", "foobar"}, ""},
+	}
+
+	for i, tc := range tcases {
+		if got := longestCommonPrefix(tc.in); got != tc.expected {
+			t.Fatalf("[%d case] expected (%s), but got (%s)", i+1, tc.expected, got)
+		}
+	}
+}
+
+func TestCompactLowerdirOption(t *testing.T) {
+	tcases := []struct {
+		opts      []string
+		commondir string
+		newopts   []string
+	}{
+		// no lowerdir or only one
+		{
+			[]string{"workdir=a"},
+			"",
+			[]string{"workdir=a"},
+		},
+		{
+			[]string{"workdir=a", "lowerdir=b"},
+			"",
+			[]string{"workdir=a", "lowerdir=b"},
+		},
+
+		// >= 2 lowerdir
+		{
+			[]string{"lowerdir=/snapshots/1/fs:/snapshots/10/fs"},
+			"/snapshots/",
+			[]string{"lowerdir=1/fs:10/fs"},
+		},
+		{
+			[]string{"lowerdir=/snapshots/1/fs:/snapshots/10/fs:/snapshots/2/fs"},
+			"/snapshots/",
+			[]string{"lowerdir=1/fs:10/fs:2/fs"},
+		},
+
+		// if common dir is /
+		{
+			[]string{"lowerdir=/snapshots/1/fs:/other_snapshots/1/fs"},
+			"",
+			[]string{"lowerdir=/snapshots/1/fs:/other_snapshots/1/fs"},
+		},
+
+		// if common dir is .
+		{
+			[]string{"lowerdir=a:aaa"},
+			"",
+			[]string{"lowerdir=a:aaa"},
+		},
+	}
+
+	for i, tc := range tcases {
+		dir, opts := compactLowerdirOption(tc.opts)
+		if dir != tc.commondir {
+			t.Fatalf("[%d case] expected common dir (%s), but got (%s)", i+1, tc.commondir, dir)
+		}
+
+		if !reflect.DeepEqual(opts, tc.newopts) {
+			t.Fatalf("[%d case] expected options (%v), but got (%v)", i+1, tc.newopts, opts)
+		}
+	}
+}
+
+func TestFUSEHelper(t *testing.T) {
+	testutil.RequiresRoot(t)
+	const fuseoverlayfsBinary = "fuse-overlayfs"
+	_, err := exec.LookPath(fuseoverlayfsBinary)
+	if err != nil {
+		t.Skip("fuse-overlayfs not installed")
+	}
+	td := t.TempDir()
+
+	for _, dir := range []string{"lower1", "lower2", "upper", "work", "merged"} {
+		if err := os.Mkdir(filepath.Join(td, dir), 0755); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	opts := fmt.Sprintf("lowerdir=%s:%s,upperdir=%s,workdir=%s", filepath.Join(td, "lower2"), filepath.Join(td, "lower1"), filepath.Join(td, "upper"), filepath.Join(td, "work"))
+	m := Mount{
+		Type:    "fuse3." + fuseoverlayfsBinary,
+		Source:  "overlay",
+		Options: []string{opts},
+	}
+	dest := filepath.Join(td, "merged")
+	if err := m.Mount(dest); err != nil {
+		t.Fatal(err)
+	}
+	if err := UnmountAll(dest, 0); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestMountAt(t *testing.T) {
+	testutil.RequiresRoot(t)
+
+	dir1 := t.TempDir()
+	dir2 := t.TempDir()
+
+	defer unix.Unmount(filepath.Join(dir2, "bar"), unix.MNT_DETACH)
+
+	if err := os.WriteFile(filepath.Join(dir1, "foo"), []byte("foo"), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := os.WriteFile(filepath.Join(dir2, "bar"), []byte{}, 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	wd, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// mount ${dir1}/foo at ${dir2}/bar
+	// But since we are using `mountAt` we only need to specify the relative path to dir2 as the target mountAt will chdir to there.
+	if err := mountAt(dir2, filepath.Join(dir1, "foo"), "bar", "none", unix.MS_BIND, ""); err != nil {
+		t.Fatal(err)
+	}
+
+	b, err := os.ReadFile(filepath.Join(dir2, "bar"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if string(b) != "foo" {
+		t.Fatalf("unexpected file content: %s", b)
+	}
+
+	newWD, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if wd != newWD {
+		t.Fatalf("unexpected working directory: %s", newWD)
+	}
+}
+
+func TestUnmountMounts(t *testing.T) {
+	testutil.RequiresRoot(t)
+
+	target, mounts := setupMounts(t)
+	if err := UnmountMounts(mounts, target, 0); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestUnmountRecursive(t *testing.T) {
+	testutil.RequiresRoot(t)
+
+	target, _ := setupMounts(t)
+	if err := UnmountRecursive(target, 0); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func setupMounts(t *testing.T) (target string, mounts []Mount) {
+	dir1 := t.TempDir()
+	dir2 := t.TempDir()
+
+	if err := os.Mkdir(filepath.Join(dir1, "foo"), 0755); err != nil {
+		t.Fatal(err)
+	}
+	mounts = append(mounts, Mount{
+		Type:   "bind",
+		Source: dir1,
+		Options: []string{
+			"ro",
+			"rbind",
+		},
+	})
+
+	if err := os.WriteFile(filepath.Join(dir2, "bar"), []byte("bar"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	mounts = append(mounts, Mount{
+		Type:   "bind",
+		Source: dir2,
+		Target: "foo",
+		Options: []string{
+			"ro",
+			"rbind",
+		},
+	})
+
+	target = t.TempDir()
+	if err := All(mounts, target); err != nil {
+		t.Fatal(err)
+	}
+
+	b, err := os.ReadFile(filepath.Join(target, "foo/bar"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if string(b) != "bar" {
+		t.Fatalf("unexpected file content: %s", b)
+	}
+
+	return target, mounts
+}