470 lines
12 KiB
Go
470 lines
12 KiB
Go
// Copyright 2018 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package fs_test
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import (
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"testing"
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"gvisor.googlesource.com/gvisor/pkg/sentry/context"
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"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
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"gvisor.googlesource.com/gvisor/pkg/sentry/fs/fsutil"
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"gvisor.googlesource.com/gvisor/pkg/sentry/fs/ramfs"
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"gvisor.googlesource.com/gvisor/pkg/sentry/kernel/contexttest"
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"gvisor.googlesource.com/gvisor/pkg/syserror"
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)
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func TestLookup(t *testing.T) {
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ctx := contexttest.Context(t)
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for _, test := range []struct {
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// Test description.
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desc string
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// Lookup parameters.
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dir *fs.Inode
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name string
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// Want from lookup.
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found bool
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hasUpper bool
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hasLower bool
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}{
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{
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desc: "no upper, lower has name",
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dir: fs.NewTestOverlayDir(ctx,
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nil, /* upper */
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "a",
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dir: false,
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},
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}, nil), /* lower */
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false /* revalidate */),
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name: "a",
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found: true,
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hasUpper: false,
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hasLower: true,
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},
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{
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desc: "no lower, upper has name",
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dir: fs.NewTestOverlayDir(ctx,
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "a",
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dir: false,
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},
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}, nil), /* upper */
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nil, /* lower */
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false /* revalidate */),
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name: "a",
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found: true,
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hasUpper: true,
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hasLower: false,
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},
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{
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desc: "upper and lower, only lower has name",
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dir: fs.NewTestOverlayDir(ctx,
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "b",
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dir: false,
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},
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}, nil), /* upper */
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "a",
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dir: false,
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},
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}, nil), /* lower */
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false /* revalidate */),
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name: "a",
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found: true,
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hasUpper: false,
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hasLower: true,
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},
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{
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desc: "upper and lower, only upper has name",
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dir: fs.NewTestOverlayDir(ctx,
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "a",
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dir: false,
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},
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}, nil), /* upper */
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "b",
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dir: false,
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},
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}, nil), /* lower */
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false /* revalidate */),
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name: "a",
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found: true,
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hasUpper: true,
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hasLower: false,
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},
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{
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desc: "upper and lower, both have file",
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dir: fs.NewTestOverlayDir(ctx,
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "a",
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dir: false,
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},
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}, nil), /* upper */
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "a",
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dir: false,
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},
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}, nil), /* lower */
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false /* revalidate */),
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name: "a",
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found: true,
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hasUpper: true,
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hasLower: false,
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},
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{
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desc: "upper and lower, both have directory",
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dir: fs.NewTestOverlayDir(ctx,
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "a",
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dir: true,
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},
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}, nil), /* upper */
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "a",
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dir: true,
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},
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}, nil), /* lower */
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false /* revalidate */),
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name: "a",
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found: true,
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hasUpper: true,
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hasLower: true,
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},
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{
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desc: "upper and lower, upper negative masks lower file",
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dir: fs.NewTestOverlayDir(ctx,
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newTestRamfsDir(ctx, nil, []string{"a"}), /* upper */
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "a",
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dir: false,
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},
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}, nil), /* lower */
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false /* revalidate */),
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name: "a",
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found: false,
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hasUpper: false,
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hasLower: false,
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},
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{
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desc: "upper and lower, upper negative does not mask lower file",
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dir: fs.NewTestOverlayDir(ctx,
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newTestRamfsDir(ctx, nil, []string{"b"}), /* upper */
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newTestRamfsDir(ctx, []dirContent{
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{
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name: "a",
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dir: false,
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},
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}, nil), /* lower */
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false /* revalidate */),
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name: "a",
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found: true,
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hasUpper: false,
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hasLower: true,
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},
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} {
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t.Run(test.desc, func(t *testing.T) {
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dirent, err := test.dir.Lookup(ctx, test.name)
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if test.found && (err == syserror.ENOENT || dirent.IsNegative()) {
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t.Fatalf("lookup %q expected to find positive dirent, got dirent %v err %v", test.name, dirent, err)
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}
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if !test.found {
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if err != syserror.ENOENT && !dirent.IsNegative() {
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t.Errorf("lookup %q expected to return ENOENT or negative dirent, got dirent %v err %v", test.name, dirent, err)
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}
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// Nothing more to check.
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return
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}
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if hasUpper := dirent.Inode.TestHasUpperFS(); hasUpper != test.hasUpper {
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t.Fatalf("lookup got upper filesystem %v, want %v", hasUpper, test.hasUpper)
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}
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if hasLower := dirent.Inode.TestHasLowerFS(); hasLower != test.hasLower {
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t.Errorf("lookup got lower filesystem %v, want %v", hasLower, test.hasLower)
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}
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})
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}
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}
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func TestLookupRevalidation(t *testing.T) {
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// File name used in the tests.
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fileName := "foofile"
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ctx := contexttest.Context(t)
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for _, tc := range []struct {
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// Test description.
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desc string
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// Upper and lower fs for the overlay.
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upper *fs.Inode
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lower *fs.Inode
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// Whether the upper requires revalidation.
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revalidate bool
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// Whether we should get the same dirent on second lookup.
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wantSame bool
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}{
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{
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desc: "file from upper with no revalidation",
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upper: newTestRamfsDir(ctx, []dirContent{{name: fileName}}, nil),
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lower: newTestRamfsDir(ctx, nil, nil),
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revalidate: false,
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wantSame: true,
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},
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{
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desc: "file from upper with revalidation",
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upper: newTestRamfsDir(ctx, []dirContent{{name: fileName}}, nil),
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lower: newTestRamfsDir(ctx, nil, nil),
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revalidate: true,
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wantSame: false,
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},
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{
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desc: "file from lower with no revalidation",
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upper: newTestRamfsDir(ctx, nil, nil),
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lower: newTestRamfsDir(ctx, []dirContent{{name: fileName}}, nil),
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revalidate: false,
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wantSame: true,
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},
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{
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desc: "file from lower with revalidation",
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upper: newTestRamfsDir(ctx, nil, nil),
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lower: newTestRamfsDir(ctx, []dirContent{{name: fileName}}, nil),
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revalidate: true,
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// The file does not exist in the upper, so we do not
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// need to revalidate it.
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wantSame: true,
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},
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{
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desc: "file from upper and lower with no revalidation",
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upper: newTestRamfsDir(ctx, []dirContent{{name: fileName}}, nil),
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lower: newTestRamfsDir(ctx, []dirContent{{name: fileName}}, nil),
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revalidate: false,
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wantSame: true,
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},
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{
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desc: "file from upper and lower with revalidation",
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upper: newTestRamfsDir(ctx, []dirContent{{name: fileName}}, nil),
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lower: newTestRamfsDir(ctx, []dirContent{{name: fileName}}, nil),
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revalidate: true,
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wantSame: false,
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},
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} {
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t.Run(tc.desc, func(t *testing.T) {
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root := fs.NewDirent(newTestRamfsDir(ctx, nil, nil), "root")
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ctx = &rootContext{
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Context: ctx,
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root: root,
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}
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overlay := fs.NewDirent(fs.NewTestOverlayDir(ctx, tc.upper, tc.lower, tc.revalidate), "overlay")
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// Lookup the file twice through the overlay.
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first, err := overlay.Walk(ctx, root, fileName)
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if err != nil {
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t.Fatalf("overlay.Walk(%q) failed: %v", fileName, err)
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}
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second, err := overlay.Walk(ctx, root, fileName)
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if err != nil {
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t.Fatalf("overlay.Walk(%q) failed: %v", fileName, err)
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}
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if tc.wantSame && first != second {
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t.Errorf("dirent lookup got different dirents, wanted same\nfirst=%+v\nsecond=%+v", first, second)
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} else if !tc.wantSame && first == second {
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t.Errorf("dirent lookup got the same dirent, wanted different: %+v", first)
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}
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})
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}
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}
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func TestCacheFlush(t *testing.T) {
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ctx := contexttest.Context(t)
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// Upper and lower each have a file.
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upperFileName := "file-from-upper"
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lowerFileName := "file-from-lower"
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upper := newTestRamfsDir(ctx, []dirContent{{name: upperFileName}}, nil)
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lower := newTestRamfsDir(ctx, []dirContent{{name: lowerFileName}}, nil)
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overlay := fs.NewTestOverlayDir(ctx, upper, lower, true /* revalidate */)
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mns, err := fs.NewMountNamespace(ctx, overlay)
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if err != nil {
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t.Fatalf("NewMountNamespace failed: %v", err)
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}
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root := mns.Root()
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defer root.DecRef()
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ctx = &rootContext{
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Context: ctx,
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root: root,
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}
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for _, fileName := range []string{upperFileName, lowerFileName} {
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// Walk to the file.
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maxTraversals := uint(0)
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dirent, err := mns.FindInode(ctx, root, nil, fileName, &maxTraversals)
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if err != nil {
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t.Fatalf("FindInode(%q) failed: %v", fileName, err)
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}
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// Get a file from the dirent.
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file, err := dirent.Inode.GetFile(ctx, dirent, fs.FileFlags{Read: true})
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if err != nil {
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t.Fatalf("GetFile() failed: %v", err)
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}
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// The dirent should have 3 refs, one from us, one from the
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// file, and one from the dirent cache.
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// dirent cache.
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if got, want := dirent.ReadRefs(), 3; int(got) != want {
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t.Errorf("dirent.ReadRefs() got %d want %d", got, want)
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}
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// Drop the file reference.
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file.DecRef()
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// Dirent should have 2 refs left.
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if got, want := dirent.ReadRefs(), 2; int(got) != want {
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t.Errorf("dirent.ReadRefs() got %d want %d", got, want)
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}
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// Flush the dirent cache.
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mns.FlushMountSourceRefs()
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// Dirent should have 1 ref left from the dirent cache.
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if got, want := dirent.ReadRefs(), 1; int(got) != want {
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t.Errorf("dirent.ReadRefs() got %d want %d", got, want)
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}
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// Drop our ref.
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dirent.DecRef()
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// We should be back to zero refs.
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if got, want := dirent.ReadRefs(), 0; int(got) != want {
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t.Errorf("dirent.ReadRefs() got %d want %d", got, want)
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}
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}
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}
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type dir struct {
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fs.InodeOperations
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// List of negative child names.
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negative []string
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// ReaddirCalled records whether Readdir was called on a file
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// corresponding to this inode.
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ReaddirCalled bool
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}
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// Getxattr implements InodeOperations.Getxattr.
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func (d *dir) Getxattr(inode *fs.Inode, name string) (string, error) {
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for _, n := range d.negative {
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if name == fs.XattrOverlayWhiteout(n) {
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return "y", nil
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}
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}
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return "", syserror.ENOATTR
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}
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// GetFile implements InodeOperations.GetFile.
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func (d *dir) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
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file, err := d.InodeOperations.GetFile(ctx, dirent, flags)
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if err != nil {
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return nil, err
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}
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defer file.DecRef()
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// Wrap the file's FileOperations in a dirFile.
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fops := &dirFile{
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FileOperations: file.FileOperations,
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inode: d,
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}
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return fs.NewFile(ctx, dirent, flags, fops), nil
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}
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type dirContent struct {
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name string
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dir bool
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}
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type dirFile struct {
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fs.FileOperations
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inode *dir
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}
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type inode struct {
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fsutil.InodeGenericChecker `state:"nosave"`
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fsutil.InodeNoExtendedAttributes `state:"nosave"`
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fsutil.InodeNoopRelease `state:"nosave"`
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fsutil.InodeNoopWriteOut `state:"nosave"`
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fsutil.InodeNotDirectory `state:"nosave"`
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fsutil.InodeNotMappable `state:"nosave"`
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fsutil.InodeNotSocket `state:"nosave"`
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fsutil.InodeNotSymlink `state:"nosave"`
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fsutil.InodeNotTruncatable `state:"nosave"`
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fsutil.InodeNotVirtual `state:"nosave"`
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fsutil.InodeSimpleAttributes
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fsutil.InodeStaticFileGetter
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}
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// Readdir implements fs.FileOperations.Readdir. It sets the ReaddirCalled
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// field on the inode.
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func (f *dirFile) Readdir(ctx context.Context, file *fs.File, ser fs.DentrySerializer) (int64, error) {
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f.inode.ReaddirCalled = true
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return f.FileOperations.Readdir(ctx, file, ser)
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}
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func newTestRamfsInode(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
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inode := fs.NewInode(&inode{
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InodeStaticFileGetter: fsutil.InodeStaticFileGetter{
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Contents: []byte("foobar"),
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},
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}, msrc, fs.StableAttr{Type: fs.RegularFile})
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return inode
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}
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func newTestRamfsDir(ctx context.Context, contains []dirContent, negative []string) *fs.Inode {
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msrc := fs.NewPseudoMountSource()
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contents := make(map[string]*fs.Inode)
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for _, c := range contains {
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if c.dir {
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contents[c.name] = newTestRamfsDir(ctx, nil, nil)
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} else {
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contents[c.name] = newTestRamfsInode(ctx, msrc)
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}
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}
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dops := ramfs.NewDir(ctx, contents, fs.RootOwner, fs.FilePermissions{
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User: fs.PermMask{Read: true, Execute: true},
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})
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return fs.NewInode(&dir{
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InodeOperations: dops,
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negative: negative,
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}, msrc, fs.StableAttr{Type: fs.Directory})
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}
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