// Copyright 2018 The gVisor 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.

// Binary syscall_test_runner runs the syscall test suites in gVisor
// containers and on the host platform.
package main

import (
	"flag"
	"fmt"
	"io/ioutil"
	"math"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"
	"syscall"
	"testing"

	specs "github.com/opencontainers/runtime-spec/specs-go"
	"golang.org/x/sys/unix"
	"gvisor.googlesource.com/gvisor/pkg/log"
	"gvisor.googlesource.com/gvisor/runsc/specutils"
	"gvisor.googlesource.com/gvisor/runsc/test/testutil"
	"gvisor.googlesource.com/gvisor/test/syscalls/gtest"
)

// Location of syscall tests, relative to the repo root.
const testDir = "test/syscalls/linux"

var (
	testName   = flag.String("test-name", "", "name of test binary to run")
	debug      = flag.Bool("debug", false, "enable debug logs")
	strace     = flag.Bool("strace", false, "enable strace logs")
	platform   = flag.String("platform", "ptrace", "platform to run on")
	useTmpfs   = flag.Bool("use-tmpfs", false, "mounts tmpfs for /tmp")
	fileAccess = flag.String("file-access", "exclusive", "mounts root in exclusive or shared mode")
	overlay    = flag.Bool("overlay", false, "wrap filesystem mounts with writable tmpfs overlay")
	parallel   = flag.Bool("parallel", false, "run tests in parallel")
	runscPath  = flag.String("runsc", "", "path to runsc binary")
)

// runTestCaseNative runs the test case directly on the host machine.
func runTestCaseNative(testBin string, tc gtest.TestCase, t *testing.T) {
	// These tests might be running in parallel, so make sure they have a
	// unique test temp dir.
	tmpDir, err := ioutil.TempDir(testutil.TmpDir(), "")
	if err != nil {
		t.Fatalf("could not create temp dir: %v", err)
	}
	defer os.RemoveAll(tmpDir)

	// Replace TEST_TMPDIR in the current environment with something
	// unique.
	env := os.Environ()
	newEnvVar := "TEST_TMPDIR=" + tmpDir
	var found bool
	for i, kv := range env {
		if strings.HasPrefix(kv, "TEST_TMPDIR=") {
			env[i] = newEnvVar
			found = true
			break
		}
	}
	if !found {
		env = append(env, newEnvVar)
	}
	// Remove env variables that cause the gunit binary to write output
	// files, since they will stomp on eachother, and on the output files
	// from this go test.
	env = filterEnv(env, []string{"GUNIT_OUTPUT", "TEST_PREMATURE_EXIT_FILE", "XML_OUTPUT_FILE"})

	// Remove shard env variables so that the gunit binary does not try to
	// intepret them.
	env = filterEnv(env, []string{"TEST_SHARD_INDEX", "TEST_TOTAL_SHARDS", "GTEST_SHARD_INDEX", "GTEST_TOTAL_SHARDS"})

	cmd := exec.Command(testBin, gtest.FilterTestFlag+"="+tc.FullName())
	cmd.Env = env
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	if err := cmd.Run(); err != nil {
		ws := err.(*exec.ExitError).Sys().(syscall.WaitStatus)
		t.Errorf("test %q exited with status %d, want 0", tc.FullName(), ws.ExitStatus())
	}
}

// runsTestCaseRunsc runs the test case in runsc.
func runTestCaseRunsc(testBin string, tc gtest.TestCase, t *testing.T) {
	rootDir, err := testutil.SetupRootDir()
	if err != nil {
		t.Fatalf("SetupRootDir failed: %v", err)
	}
	defer os.RemoveAll(rootDir)

	// Run a new container with the test executable and filter for the
	// given test suite and name.
	spec := testutil.NewSpecWithArgs(testBin, gtest.FilterTestFlag+"="+tc.FullName())

	// Mark the root as writeable, as some tests attempt to
	// write to the rootfs, and expect EACCES, not EROFS.
	spec.Root.Readonly = false

	// Test spec comes with pre-defined mounts that we don't want. Reset it.
	spec.Mounts = nil
	if *useTmpfs {
		// Forces '/tmp' to be mounted as tmpfs, otherwise test that rely on
		// features only available in gVisor's internal tmpfs may fail.
		spec.Mounts = append(spec.Mounts, specs.Mount{
			Destination: "/tmp",
			Type:        "tmpfs",
		})
	} else {
		// Use a gofer-backed directory as '/tmp'.
		//
		// Tests might be running in parallel, so make sure each has a
		// unique test temp dir.
		//
		// Some tests (e.g., sticky) access this mount from other
		// users, so make sure it is world-accessible.
		tmpDir, err := ioutil.TempDir(testutil.TmpDir(), "")
		if err != nil {
			t.Fatalf("could not create temp dir: %v", err)
		}
		defer os.RemoveAll(tmpDir)

		if err := os.Chmod(tmpDir, 0777); err != nil {
			t.Fatalf("could not chmod temp dir: %v", err)
		}

		spec.Mounts = append(spec.Mounts, specs.Mount{
			Type:        "bind",
			Destination: "/tmp",
			Source:      tmpDir,
		})
	}

	// Set environment variable that indicates we are
	// running in gVisor and with the given platform.
	platformVar := "TEST_ON_GVISOR"
	env := append(os.Environ(), platformVar+"="+*platform)

	// Remove env variables that cause the gunit binary to write output
	// files, since they will stomp on eachother, and on the output files
	// from this go test.
	env = filterEnv(env, []string{"GUNIT_OUTPUT", "TEST_PREMATURE_EXIT_FILE", "XML_OUTPUT_FILE"})

	// Remove shard env variables so that the gunit binary does not try to
	// intepret them.
	env = filterEnv(env, []string{"TEST_SHARD_INDEX", "TEST_TOTAL_SHARDS", "GTEST_SHARD_INDEX", "GTEST_TOTAL_SHARDS"})

	// Set TEST_TMPDIR to /tmp, as some of the syscall tests require it to
	// be backed by tmpfs.
	for i, kv := range env {
		if strings.HasPrefix(kv, "TEST_TMPDIR=") {
			env[i] = "TEST_TMPDIR=/tmp"
			break
		}
	}

	spec.Process.Env = env

	bundleDir, err := testutil.SetupBundleDir(spec)
	if err != nil {
		t.Fatalf("SetupBundleDir failed: %v", err)
	}
	defer os.RemoveAll(bundleDir)

	id := testutil.UniqueContainerID()
	log.Infof("Running test %q in container %q", tc.FullName(), id)
	specutils.LogSpec(spec)

	args := []string{
		"-platform", *platform,
		"-root", rootDir,
		"-file-access", *fileAccess,
		"-network=none",
		"-log-format=text",
		"-TESTONLY-unsafe-nonroot=true",
		"-net-raw=true",
	}
	if *overlay {
		args = append(args, "-overlay")
	}
	if *debug {
		args = append(args, "-debug", "-log-packets=true")
	}
	if *strace {
		args = append(args, "-strace")
	}
	if outDir, ok := syscall.Getenv("TEST_UNDECLARED_OUTPUTS_DIR"); ok {
		tdir := filepath.Join(outDir, strings.Replace(tc.FullName(), "/", "_", -1))
		if err := os.MkdirAll(tdir, 0755); err != nil {
			t.Fatalf("could not create test dir: %v", err)
		}
		debugLogDir, err := ioutil.TempDir(tdir, "runsc")
		if err != nil {
			t.Fatalf("could not create temp dir: %v", err)
		}
		debugLogDir += "/"
		log.Infof("runsc logs: %s", debugLogDir)
		args = append(args, "-debug-log", debugLogDir)

		// Default -log sends messages to stderr which makes reading the test log
		// difficult. Instead, drop them when debug log is enabled given it's a
		// better place for these messages.
		args = append(args, "-log=/dev/null")
	}

	// Current process doesn't have CAP_SYS_ADMIN, create user namespace and run
	// as root inside that namespace to get it.
	args = append(args, "run", "--bundle", bundleDir, id)
	cmd := exec.Command(*runscPath, args...)
	cmd.SysProcAttr = &syscall.SysProcAttr{
		Cloneflags: syscall.CLONE_NEWUSER | syscall.CLONE_NEWNS,
		// Set current user/group as root inside the namespace.
		UidMappings: []syscall.SysProcIDMap{
			{ContainerID: 0, HostID: os.Getuid(), Size: 1},
		},
		GidMappings: []syscall.SysProcIDMap{
			{ContainerID: 0, HostID: os.Getgid(), Size: 1},
		},
		GidMappingsEnableSetgroups: false,
		Credential: &syscall.Credential{
			Uid: 0,
			Gid: 0,
		},
	}
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	if err = cmd.Run(); err != nil {
		t.Errorf("test %q exited with status %v, want 0", tc.FullName(), err)
	}
}

// filterEnv returns an environment with the blacklisted variables removed.
func filterEnv(env, blacklist []string) []string {
	var out []string
	for _, kv := range env {
		ok := true
		for _, k := range blacklist {
			if strings.HasPrefix(kv, k+"=") {
				ok = false
				break
			}
		}
		if ok {
			out = append(out, kv)
		}
	}
	return out
}

func fatalf(s string, args ...interface{}) {
	fmt.Fprintf(os.Stderr, s+"\n", args...)
	os.Exit(1)
}

func matchString(a, b string) (bool, error) {
	return a == b, nil
}

func main() {
	flag.Parse()
	if *testName == "" {
		fatalf("test-name flag must be provided")
	}

	log.SetLevel(log.Warning)
	if *debug {
		log.SetLevel(log.Debug)
	}

	if *platform != "native" && *runscPath == "" {
		if err := testutil.ConfigureExePath(); err != nil {
			panic(err.Error())
		}
		*runscPath = specutils.ExePath
	}

	// Make sure stdout and stderr are opened with O_APPEND, otherwise logs
	// from outside the sandbox can (and will) stomp on logs from inside
	// the sandbox.
	for _, f := range []*os.File{os.Stdout, os.Stderr} {
		flags, err := unix.FcntlInt(f.Fd(), unix.F_GETFL, 0)
		if err != nil {
			fatalf("error getting file flags for %v: %v", f, err)
		}
		if flags&unix.O_APPEND == 0 {
			flags |= unix.O_APPEND
			if _, err := unix.FcntlInt(f.Fd(), unix.F_SETFL, flags); err != nil {
				fatalf("error setting file flags for %v: %v", f, err)
			}
		}
	}

	// Get path to test binary.
	fullTestName := filepath.Join(testDir, *testName)
	testBin, err := testutil.FindFile(fullTestName)
	if err != nil {
		fatalf("FindFile(%q) failed: %v", fullTestName, err)
	}

	// Get all test cases in each binary.
	testCases, err := gtest.ParseTestCases(testBin)
	if err != nil {
		fatalf("ParseTestCases(%q) failed: %v", testBin, err)
	}

	// If sharding, then get the subset of tests to run based on the shard index.
	if indexStr, totalStr := os.Getenv("TEST_SHARD_INDEX"), os.Getenv("TEST_TOTAL_SHARDS"); indexStr != "" && totalStr != "" {
		// Parse index and total to ints.
		index, err := strconv.Atoi(indexStr)
		if err != nil {
			fatalf("invalid TEST_SHARD_INDEX %q: %v", indexStr, err)
		}
		total, err := strconv.Atoi(totalStr)
		if err != nil {
			fatalf("invalid TEST_TOTAL_SHARDS %q: %v", totalStr, err)
		}
		// Calculate subslice of tests to run.
		shardSize := int(math.Ceil(float64(len(testCases)) / float64(total)))
		begin := index * shardSize
		// Set end as begin of next subslice.
		end := ((index + 1) * shardSize)
		if begin > len(testCases) {
			// Nothing to run.
			return
		}
		if end > len(testCases) {
			end = len(testCases)
		}
		testCases = testCases[begin:end]
	}

	var tests []testing.InternalTest
	for _, tc := range testCases {
		// Capture tc.
		tc := tc
		testName := fmt.Sprintf("%s_%s", tc.Suite, tc.Name)
		tests = append(tests, testing.InternalTest{
			Name: testName,
			F: func(t *testing.T) {
				if *parallel {
					t.Parallel()
				}
				if *platform == "native" {
					// Run the test case on host.
					runTestCaseNative(testBin, tc, t)
				} else {
					// Run the test case in runsc.
					runTestCaseRunsc(testBin, tc, t)
				}
			},
		})
	}

	testing.Main(matchString, tests, nil, nil)
}