Golang程序
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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package syscall_test
import (
"bufio"
"fmt"
"io"
"io/ioutil"
"os"
"os/exec"
"os/signal"
"path/filepath"
"runtime"
"strconv"
"strings"
"syscall"
"testing"
"time"
"unsafe"
)
// chtmpdir changes the working directory to a new temporary directory and
// provides a cleanup function. Used when PWD is read-only.
func chtmpdir(t *testing.T) func() {
oldwd, err := os.Getwd()
if err != nil {
t.Fatalf("chtmpdir: %v", err)
}
d, err := ioutil.TempDir("", "test")
if err != nil {
t.Fatalf("chtmpdir: %v", err)
}
if err := os.Chdir(d); err != nil {
t.Fatalf("chtmpdir: %v", err)
}
return func() {
if err := os.Chdir(oldwd); err != nil {
t.Fatalf("chtmpdir: %v", err)
}
os.RemoveAll(d)
}
}
func touch(t *testing.T, name string) {
f, err := os.Create(name)
if err != nil {
t.Fatal(err)
}
if err := f.Close(); err != nil {
t.Fatal(err)
}
}
const (
_AT_SYMLINK_NOFOLLOW = 0x100
_AT_FDCWD = -0x64
_AT_EACCESS = 0x200
_F_OK = 0
_R_OK = 4
)
func TestFaccessat(t *testing.T) {
defer chtmpdir(t)()
touch(t, "file1")
err := syscall.Faccessat(_AT_FDCWD, "file1", _R_OK, 0)
if err != nil {
t.Errorf("Faccessat: unexpected error: %v", err)
}
err = syscall.Faccessat(_AT_FDCWD, "file1", _R_OK, 2)
if err != syscall.EINVAL {
t.Errorf("Faccessat: unexpected error: %v, want EINVAL", err)
}
err = syscall.Faccessat(_AT_FDCWD, "file1", _R_OK, _AT_EACCESS)
if err != nil {
t.Errorf("Faccessat: unexpected error: %v", err)
}
err = os.Symlink("file1", "symlink1")
if err != nil {
t.Fatal(err)
}
err = syscall.Faccessat(_AT_FDCWD, "symlink1", _R_OK, _AT_SYMLINK_NOFOLLOW)
if err != nil {
t.Errorf("Faccessat SYMLINK_NOFOLLOW: unexpected error %v", err)
}
// We can't really test _AT_SYMLINK_NOFOLLOW, because there
// doesn't seem to be any way to change the mode of a symlink.
// We don't test _AT_EACCESS because such tests are only
// meaningful if run as root.
err = syscall.Fchmodat(_AT_FDCWD, "file1", 0, 0)
if err != nil {
t.Errorf("Fchmodat: unexpected error %v", err)
}
err = syscall.Faccessat(_AT_FDCWD, "file1", _F_OK, _AT_SYMLINK_NOFOLLOW)
if err != nil {
t.Errorf("Faccessat: unexpected error: %v", err)
}
err = syscall.Faccessat(_AT_FDCWD, "file1", _R_OK, _AT_SYMLINK_NOFOLLOW)
if err != syscall.EACCES {
if syscall.Getuid() != 0 {
t.Errorf("Faccessat: unexpected error: %v, want EACCES", err)
}
}
}
func TestFchmodat(t *testing.T) {
defer chtmpdir(t)()
touch(t, "file1")
os.Symlink("file1", "symlink1")
err := syscall.Fchmodat(_AT_FDCWD, "symlink1", 0444, 0)
if err != nil {
t.Fatalf("Fchmodat: unexpected error: %v", err)
}
fi, err := os.Stat("file1")
if err != nil {
t.Fatal(err)
}
if fi.Mode() != 0444 {
t.Errorf("Fchmodat: failed to change mode: expected %v, got %v", 0444, fi.Mode())
}
err = syscall.Fchmodat(_AT_FDCWD, "symlink1", 0444, _AT_SYMLINK_NOFOLLOW)
if err != syscall.EOPNOTSUPP {
t.Fatalf("Fchmodat: unexpected error: %v, expected EOPNOTSUPP", err)
}
}
func TestMain(m *testing.M) {
if os.Getenv("GO_DEATHSIG_PARENT") == "1" {
deathSignalParent()
} else if os.Getenv("GO_DEATHSIG_CHILD") == "1" {
deathSignalChild()
} else if os.Getenv("GO_SYSCALL_NOERROR") == "1" {
syscallNoError()
}
os.Exit(m.Run())
}
func TestLinuxDeathSignal(t *testing.T) {
if os.Getuid() != 0 {
t.Skip("skipping root only test")
}
// Copy the test binary to a location that a non-root user can read/execute
// after we drop privileges
tempDir, err := ioutil.TempDir("", "TestDeathSignal")
if err != nil {
t.Fatalf("cannot create temporary directory: %v", err)
}
defer os.RemoveAll(tempDir)
os.Chmod(tempDir, 0755)
tmpBinary := filepath.Join(tempDir, filepath.Base(os.Args[0]))
src, err := os.Open(os.Args[0])
if err != nil {
t.Fatalf("cannot open binary %q, %v", os.Args[0], err)
}
defer src.Close()
dst, err := os.OpenFile(tmpBinary, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0755)
if err != nil {
t.Fatalf("cannot create temporary binary %q, %v", tmpBinary, err)
}
if _, err := io.Copy(dst, src); err != nil {
t.Fatalf("failed to copy test binary to %q, %v", tmpBinary, err)
}
err = dst.Close()
if err != nil {
t.Fatalf("failed to close test binary %q, %v", tmpBinary, err)
}
cmd := exec.Command(tmpBinary)
cmd.Env = []string{"GO_DEATHSIG_PARENT=1"}
chldStdin, err := cmd.StdinPipe()
if err != nil {
t.Fatalf("failed to create new stdin pipe: %v", err)
}
chldStdout, err := cmd.StdoutPipe()
if err != nil {
t.Fatalf("failed to create new stdout pipe: %v", err)
}
cmd.Stderr = os.Stderr
err = cmd.Start()
defer cmd.Wait()
if err != nil {
t.Fatalf("failed to start first child process: %v", err)
}
chldPipe := bufio.NewReader(chldStdout)
if got, err := chldPipe.ReadString('\n'); got == "start\n" {
syscall.Kill(cmd.Process.Pid, syscall.SIGTERM)
go func() {
time.Sleep(5 * time.Second)
chldStdin.Close()
}()
want := "ok\n"
if got, err = chldPipe.ReadString('\n'); got != want {
t.Fatalf("expected %q, received %q, %v", want, got, err)
}
} else {
t.Fatalf("did not receive start from child, received %q, %v", got, err)
}
}
func deathSignalParent() {
cmd := exec.Command(os.Args[0])
cmd.Env = []string{"GO_DEATHSIG_CHILD=1"}
cmd.Stdin = os.Stdin
cmd.Stdout = os.Stdout
attrs := syscall.SysProcAttr{
Pdeathsig: syscall.SIGUSR1,
// UID/GID 99 is the user/group "nobody" on RHEL/Fedora and is
// unused on Ubuntu
Credential: &syscall.Credential{Uid: 99, Gid: 99},
}
cmd.SysProcAttr = &attrs
err := cmd.Start()
if err != nil {
fmt.Fprintf(os.Stderr, "death signal parent error: %v\n", err)
os.Exit(1)
}
cmd.Wait()
os.Exit(0)
}
func deathSignalChild() {
c := make(chan os.Signal, 1)
signal.Notify(c, syscall.SIGUSR1)
go func() {
<-c
fmt.Println("ok")
os.Exit(0)
}()
fmt.Println("start")
buf := make([]byte, 32)
os.Stdin.Read(buf)
// We expected to be signaled before stdin closed
fmt.Println("not ok")
os.Exit(1)
}
func TestParseNetlinkMessage(t *testing.T) {
for i, b := range [][]byte{
{103, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 11, 0, 1, 0, 0, 0, 0, 5, 8, 0, 3,
0, 8, 0, 6, 0, 0, 0, 0, 1, 63, 0, 10, 0, 69, 16, 0, 59, 39, 82, 64, 0, 64, 6, 21, 89, 127, 0, 0,
1, 127, 0, 0, 1, 230, 228, 31, 144, 32, 186, 155, 211, 185, 151, 209, 179, 128, 24, 1, 86,
53, 119, 0, 0, 1, 1, 8, 10, 0, 17, 234, 12, 0, 17, 189, 126, 107, 106, 108, 107, 106, 13, 10,
},
{106, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 11, 0, 1, 0, 0, 0, 0, 3, 8, 0, 3,
0, 8, 0, 6, 0, 0, 0, 0, 1, 66, 0, 10, 0, 69, 0, 0, 62, 230, 255, 64, 0, 64, 6, 85, 184, 127, 0, 0,
1, 127, 0, 0, 1, 237, 206, 31, 144, 73, 197, 128, 65, 250, 60, 192, 97, 128, 24, 1, 86, 253, 21, 0,
0, 1, 1, 8, 10, 0, 51, 106, 89, 0, 51, 102, 198, 108, 104, 106, 108, 107, 104, 108, 107, 104, 10,
},
{102, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 11, 0, 1, 0, 0, 0, 0, 1, 8, 0, 3, 0,
8, 0, 6, 0, 0, 0, 0, 1, 62, 0, 10, 0, 69, 0, 0, 58, 231, 2, 64, 0, 64, 6, 85, 185, 127, 0, 0, 1, 127,
0, 0, 1, 237, 206, 31, 144, 73, 197, 128, 86, 250, 60, 192, 97, 128, 24, 1, 86, 104, 64, 0, 0, 1, 1, 8,
10, 0, 52, 198, 200, 0, 51, 135, 232, 101, 115, 97, 103, 103, 10,
},
} {
m, err := syscall.ParseNetlinkMessage(b)
if err != syscall.EINVAL {
t.Errorf("#%d: got %v; want EINVAL", i, err)
}
if m != nil {
t.Errorf("#%d: got %v; want nil", i, m)
}
}
}
func TestSyscallNoError(t *testing.T) {
// On Linux there are currently no syscalls which don't fail and return
// a value larger than 0xfffffffffffff001 so we could test RawSyscall
// vs. RawSyscallNoError on 64bit architectures.
if unsafe.Sizeof(uintptr(0)) != 4 {
t.Skip("skipping on non-32bit architecture")
}
if os.Getuid() != 0 {
t.Skip("skipping root only test")
}
if runtime.GOOS == "android" {
t.Skip("skipping on rooted android, see issue 27364")
}
// Copy the test binary to a location that a non-root user can read/execute
// after we drop privileges
tempDir, err := ioutil.TempDir("", "TestSyscallNoError")
if err != nil {
t.Fatalf("cannot create temporary directory: %v", err)
}
defer os.RemoveAll(tempDir)
os.Chmod(tempDir, 0755)
tmpBinary := filepath.Join(tempDir, filepath.Base(os.Args[0]))
src, err := os.Open(os.Args[0])
if err != nil {
t.Fatalf("cannot open binary %q, %v", os.Args[0], err)
}
defer src.Close()
dst, err := os.OpenFile(tmpBinary, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0755)
if err != nil {
t.Fatalf("cannot create temporary binary %q, %v", tmpBinary, err)
}
if _, err := io.Copy(dst, src); err != nil {
t.Fatalf("failed to copy test binary to %q, %v", tmpBinary, err)
}
err = dst.Close()
if err != nil {
t.Fatalf("failed to close test binary %q, %v", tmpBinary, err)
}
uid := uint32(0xfffffffe)
err = os.Chown(tmpBinary, int(uid), -1)
if err != nil {
t.Fatalf("failed to chown test binary %q, %v", tmpBinary, err)
}
err = os.Chmod(tmpBinary, 0755|os.ModeSetuid)
if err != nil {
t.Fatalf("failed to set setuid bit on test binary %q, %v", tmpBinary, err)
}
cmd := exec.Command(tmpBinary)
cmd.Env = []string{"GO_SYSCALL_NOERROR=1"}
out, err := cmd.CombinedOutput()
if err != nil {
t.Fatalf("failed to start first child process: %v", err)
}
got := strings.TrimSpace(string(out))
want := strconv.FormatUint(uint64(uid)+1, 10) + " / " +
strconv.FormatUint(uint64(-uid), 10) + " / " +
strconv.FormatUint(uint64(uid), 10)
if got != want {
if filesystemIsNoSUID(tmpBinary) {
t.Skip("skipping test when temp dir is mounted nosuid")
}
t.Errorf("expected %s, got %s", want, got)
}
}
// filesystemIsNoSUID reports whether the filesystem for the given
// path is mounted nosuid.
func filesystemIsNoSUID(path string) bool {
var st syscall.Statfs_t
if syscall.Statfs(path, &st) != nil {
return false
}
return st.Flags&syscall.MS_NOSUID != 0
}
func syscallNoError() {
// Test that the return value from SYS_GETEUID32 (which cannot fail)
// doesn't get treated as an error (see https://golang.org/issue/22924)
euid1, _, e := syscall.RawSyscall(syscall.Sys_GETEUID, 0, 0, 0)
euid2, _ := syscall.RawSyscallNoError(syscall.Sys_GETEUID, 0, 0, 0)
fmt.Println(uintptr(euid1), "/", int(e), "/", uintptr(euid2))
os.Exit(0)
}