localfilereader/local_file_reader_test.go

// Copyright 2021 Google LLC
//
// 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 localfilereader_test

import (
	"context"
	"io/ioutil"
	"os"
	"os/user"
	"path/filepath"
	"strconv"
	"testing"

	"github.com/google/go-cmp/cmp"
	"github.com/google/go-cmp/cmp/cmpopts"
	"google.golang.org/protobuf/testing/protocmp"
	"github.com/google/localtoast/localfilereader"
	"github.com/google/localtoast/scanapi"
	apb "github.com/google/localtoast/scannerlib/proto/api_go_proto"
)

const (
	fileName        = "file"
	fileContent     = "FILE_CONTENT"
	filePermission  = 0640
	dirName         = "dir"
	fileSymlinkName = "file_symlink"
	dirSymlinkName  = "dir_symlink"
)

// Create some temporary files before running the tests. Returns the test directory path.
func createTestFiles(t *testing.T) string {
	testDirPath := t.TempDir()
	if err := ioutil.WriteFile(filepath.Join(testDirPath, fileName), []byte(fileContent), filePermission); err != nil {
		t.Fatalf("error creating file %s: %v", filepath.Join(testDirPath, fileName), err)
	}
	if err := os.Mkdir(filepath.Join(testDirPath, dirName), filePermission); err != nil {
		t.Fatalf("error creating directory %s: %v", filepath.Join(testDirPath, dirName), err)
	}
	if err := os.Symlink(filepath.Join(testDirPath, fileName), filepath.Join(testDirPath, fileSymlinkName)); err != nil {
		t.Fatalf("error creating symlink %s: %v", filepath.Join(testDirPath, fileSymlinkName), err)
	}
	if err := os.Symlink(filepath.Join(testDirPath, dirName), filepath.Join(testDirPath, dirSymlinkName)); err != nil {
		t.Fatalf("error creating symlink %s: %v", filepath.Join(testDirPath, dirSymlinkName), err)
	}

	return testDirPath
}

func TestOpenFile(t *testing.T) {
	testDirPath := createTestFiles(t)
	testFilePath := filepath.Join(testDirPath, fileName)
	reader, err := localfilereader.OpenFile(context.Background(), testFilePath)
	if err != nil {
		t.Fatalf("localfilereader.OpenFile(%s) had unexpected error: %v", testFilePath, err)
	}
	content, err := ioutil.ReadAll(reader)
	if err != nil {
		t.Fatalf("Reading file %s had unexpected error: %v", testFilePath, err)
	}
	if string(content) != fileContent {
		t.Errorf("Got file content %q, expected %q", content, fileContent)
	}
}

func TestOpenPropagatesError(t *testing.T) {
	testDirPath := createTestFiles(t)
	nonExistentFilePath := filepath.Join(testDirPath, "non-existent-file")
	_, err := localfilereader.OpenFile(context.Background(), nonExistentFilePath)
	if err == nil {
		t.Errorf("localfilereader.OpenFile(%s) didn't return an error", nonExistentFilePath)
	}
}

func TestOpenDir(t *testing.T) {
	testDirPath := createTestFiles(t)
	d, err := localfilereader.OpenDir(context.Background(), testDirPath)
	if err != nil {
		t.Fatalf("localfilereader.OpenDir(%s) had unexpected error: %v", testDirPath, err)
	}
	files, err := scanapi.DirReaderToSlice(d)
	if err != nil {
		t.Fatalf("scanapi.DirReaderToSlice had unexpected error: %v", err)
	}
	expected := []*apb.DirContent{
		&apb.DirContent{Name: fileName, IsDir: false, IsSymlink: false},
		&apb.DirContent{Name: dirName, IsDir: true, IsSymlink: false},
		&apb.DirContent{Name: fileSymlinkName, IsDir: false, IsSymlink: true},
		&apb.DirContent{Name: dirSymlinkName, IsDir: false, IsSymlink: true},
	}
	sortProtosOpt := cmpopts.SortSlices(func(c1, c2 *apb.DirContent) bool {
		return c1.String() < c2.String()
	})
	if diff := cmp.Diff(expected, files, protocmp.Transform(), sortProtosOpt); diff != "" {
		t.Errorf("localfilereader.OpenDir(%s) returned unexpected diff (-want +got):\n%s", testDirPath, diff)
	}
}

func TestOpenDirPropagatesError(t *testing.T) {
	testDirPath := createTestFiles(t)
	nonExistentDirPath := filepath.Join(testDirPath, "non-existent-dir")
	d, err := localfilereader.OpenDir(context.Background(), nonExistentDirPath)
	if err == nil {
		d.Close()
		t.Errorf("localfilereader.OpenDir(%s) err got: %v, want: error", nonExistentDirPath, err)
	}
}

func TestOpenDirErrNextAfterRemove(t *testing.T) {
	testDirPath := createTestFiles(t)
	dirPath := filepath.Join(testDirPath, dirName)
	d, err := localfilereader.OpenDir(context.Background(), dirPath)
	if err != nil {
		t.Fatalf("localfilereader.OpenDir(%s) had unexpected error: %v", dirPath, err)
	}
	defer d.Close()
	if err = os.Remove(dirPath); err != nil {
		t.Fatalf("os.Remove(%s) had unexpected error: %v", dirPath, err)
	}

	if got := d.Next(); !got {
		t.Fatalf("DirReader.Next() got: %v, want: true", got)
	}
	if _, err := d.Entry(); err == nil {
		t.Errorf("DirReader.Entry() err got: %v, want: error", err)
	}
}

func TestOpenDirErrEntryBeforeNext(t *testing.T) {
	testDirPath := createTestFiles(t)
	dirPath := filepath.Join(testDirPath, dirName)
	d, err := localfilereader.OpenDir(context.Background(), dirPath)
	if err != nil {
		t.Fatalf("localfilereader.OpenDir(%s) had unexpected error: %v", dirPath, err)
	}
	defer d.Close()
	if _, err := d.Entry(); err == nil {
		t.Errorf("DirReader.Entry() err got: %v, want: error", err)
	}
}

func TestOpenDirErrAfterClose(t *testing.T) {
	testDirPath := createTestFiles(t)
	dirPath := filepath.Join(testDirPath, dirName)
	d, err := localfilereader.OpenDir(context.Background(), dirPath)
	if err != nil {
		t.Fatalf("localfilereader.OpenDir(%s) had unexpected error: %v", dirPath, err)
	}
	d.Close()
	if got := d.Next(); !got {
		t.Fatalf("DirReader.Next() got: %v, want: true", got)
	}
	if _, err := d.Entry(); err == nil {
		t.Errorf("DirReader.Entry() err got: %v, want: error", err)
	}
}

func TestFilePermissionsCorrectPermissionNumbers(t *testing.T) {
	testDirPath := createTestFiles(t)
	testFilePath := filepath.Join(testDirPath, fileName)
	permission, err := localfilereader.FilePermissions(context.Background(), testFilePath)
	if err != nil {
		t.Fatalf("localfilereader.FilePermissions(%s) had unexpected error: %v", testFilePath, err)
	}
	if permission.GetPermissionNum() != filePermission {
		t.Fatalf("localfilereader.FilePermissions(%s) returned %o, expected %o",
			testFilePath, permission.GetPermissionNum(), filePermission)
	}
}

func TestFilePermissionsCorrectSpecialFlags(t *testing.T) {
	testDirPath := createTestFiles(t)
	testFilePath := filepath.Join(testDirPath, fileName)
	testCases := []struct {
		desc            string
		flagToAdd       os.FileMode
		expectedSetFlag int32
	}{
		{desc: "setuid", flagToAdd: os.ModeSetuid, expectedSetFlag: localfilereader.SetuidFlag},
		{desc: "setgid", flagToAdd: os.ModeSetgid, expectedSetFlag: localfilereader.SetgidFlag},
		{desc: "sticky", flagToAdd: os.ModeSticky, expectedSetFlag: localfilereader.StickyFlag},
	}
	for _, tc := range testCases {
		t.Run(tc.desc, func(t *testing.T) {
			os.Chmod(testFilePath, os.FileMode(filePermission)|tc.flagToAdd)
			permission, err := localfilereader.FilePermissions(context.Background(), testFilePath)
			if err != nil {
				t.Fatalf("localfilereader.FilePermissions(%s) had unexpected error: %v", testFilePath, err)
			}
			if permission.GetPermissionNum()&tc.expectedSetFlag == 0 {
				t.Fatalf("localfilereader.FilePermissions(%s) returned %o, expected %o flag to be set",
					testFilePath, permission.GetPermissionNum(), tc.expectedSetFlag)
			}
		})
	}
}

func TestFilePermissionsPropagatesError(t *testing.T) {
	testDirPath := createTestFiles(t)
	nonExistentFilePath := filepath.Join(testDirPath, "non-existent-file")
	_, err := localfilereader.FilePermissions(context.Background(), nonExistentFilePath)
	if err == nil {
		t.Errorf("localfilereader.FilePermissions(%s) didn't return an error", nonExistentFilePath)
	}
}

func TestFileOwnerCurrentUser(t *testing.T) {
	testDirPath := createTestFiles(t)
	testFilePath := filepath.Join(testDirPath, fileName)
	perm, err := localfilereader.FilePermissions(context.Background(), testFilePath)
	if err != nil {
		t.Fatalf("localfilereader.FilePermissions(%s) had unexpected error: %v", testFilePath, err)
	}
	currUser, err := user.Current()
	if err != nil {
		t.Fatalf("user.Current() had unexpected error: %v", err)
	}
	if strconv.Itoa(int(perm.Uid)) != currUser.Uid {
		t.Fatalf("localfilereader.FilePermissions(%s) returned Uid %v, expected %v",
			testFilePath, perm.Uid, currUser.Uid)
	}
	if perm.User != currUser.Username {
		t.Fatalf("localfilereader.FilePermissions(%s) returned User %v, expected %v",
			testFilePath, perm.User, currUser.Username)
	}
}

func TestFilePermissionsDontChange(t *testing.T) {
	testDirPath := createTestFiles(t)
	testFilePath := filepath.Join(testDirPath, fileName)
	perm1, err := localfilereader.FilePermissions(context.Background(), testFilePath)
	if err != nil {
		t.Fatalf("localfilereader.FilePermissions(%s) had unexpected error: %v", testFilePath, err)
	}
	perm2, err := localfilereader.FilePermissions(context.Background(), testFilePath)
	if err != nil {
		t.Fatalf("localfilereader.FilePermissions(%s) had unexpected error: %v", testFilePath, err)
	}
	if diff := cmp.Diff(perm1, perm2, protocmp.Transform()); diff != "" {
		t.Fatalf("Second call to localfilereader.FilePermissions(%s) returned %v, expected %v",
			testFilePath, perm2, perm1)
	}
}