4f157ed774
This is a partial backport of https://golang.org/cl/233318. It's only a partial backport because part of the change was already applied to libgo in CL 193497 as part of the update to the Go 1.13beta1 release. Fixes PR go/95061 Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/233359
405 lines
11 KiB
Go
405 lines
11 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package syscall_test
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import (
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"bufio"
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"fmt"
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"io"
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"io/ioutil"
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"os"
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"os/exec"
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"os/signal"
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"path/filepath"
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"runtime"
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"strconv"
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"strings"
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"syscall"
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"testing"
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"time"
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"unsafe"
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)
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// chtmpdir changes the working directory to a new temporary directory and
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// provides a cleanup function. Used when PWD is read-only.
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func chtmpdir(t *testing.T) func() {
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oldwd, err := os.Getwd()
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if err != nil {
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t.Fatalf("chtmpdir: %v", err)
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}
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d, err := ioutil.TempDir("", "test")
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if err != nil {
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t.Fatalf("chtmpdir: %v", err)
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}
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if err := os.Chdir(d); err != nil {
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t.Fatalf("chtmpdir: %v", err)
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}
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return func() {
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if err := os.Chdir(oldwd); err != nil {
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t.Fatalf("chtmpdir: %v", err)
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}
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os.RemoveAll(d)
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}
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}
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func touch(t *testing.T, name string) {
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f, err := os.Create(name)
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if err != nil {
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t.Fatal(err)
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}
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if err := f.Close(); err != nil {
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t.Fatal(err)
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}
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}
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const (
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_AT_SYMLINK_NOFOLLOW = 0x100
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_AT_FDCWD = -0x64
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_AT_EACCESS = 0x200
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_F_OK = 0
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_R_OK = 4
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)
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func TestFaccessat(t *testing.T) {
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defer chtmpdir(t)()
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touch(t, "file1")
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err := syscall.Faccessat(_AT_FDCWD, "file1", _R_OK, 0)
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if err != nil {
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t.Errorf("Faccessat: unexpected error: %v", err)
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}
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err = syscall.Faccessat(_AT_FDCWD, "file1", _R_OK, 2)
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if err != syscall.EINVAL {
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t.Errorf("Faccessat: unexpected error: %v, want EINVAL", err)
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}
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err = syscall.Faccessat(_AT_FDCWD, "file1", _R_OK, _AT_EACCESS)
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if err != nil {
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t.Errorf("Faccessat: unexpected error: %v", err)
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}
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err = os.Symlink("file1", "symlink1")
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if err != nil {
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t.Fatal(err)
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}
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err = syscall.Faccessat(_AT_FDCWD, "symlink1", _R_OK, _AT_SYMLINK_NOFOLLOW)
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if err != nil {
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t.Errorf("Faccessat SYMLINK_NOFOLLOW: unexpected error %v", err)
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}
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// We can't really test _AT_SYMLINK_NOFOLLOW, because there
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// doesn't seem to be any way to change the mode of a symlink.
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// We don't test _AT_EACCESS because such tests are only
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// meaningful if run as root.
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err = syscall.Fchmodat(_AT_FDCWD, "file1", 0, 0)
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if err != nil {
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t.Errorf("Fchmodat: unexpected error %v", err)
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}
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err = syscall.Faccessat(_AT_FDCWD, "file1", _F_OK, _AT_SYMLINK_NOFOLLOW)
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if err != nil {
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t.Errorf("Faccessat: unexpected error: %v", err)
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}
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err = syscall.Faccessat(_AT_FDCWD, "file1", _R_OK, _AT_SYMLINK_NOFOLLOW)
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if err != syscall.EACCES {
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if syscall.Getuid() != 0 {
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t.Errorf("Faccessat: unexpected error: %v, want EACCES", err)
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}
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}
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}
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func TestFchmodat(t *testing.T) {
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defer chtmpdir(t)()
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touch(t, "file1")
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os.Symlink("file1", "symlink1")
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err := syscall.Fchmodat(_AT_FDCWD, "symlink1", 0444, 0)
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if err != nil {
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t.Fatalf("Fchmodat: unexpected error: %v", err)
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}
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fi, err := os.Stat("file1")
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if err != nil {
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t.Fatal(err)
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}
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if fi.Mode() != 0444 {
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t.Errorf("Fchmodat: failed to change mode: expected %v, got %v", 0444, fi.Mode())
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}
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err = syscall.Fchmodat(_AT_FDCWD, "symlink1", 0444, _AT_SYMLINK_NOFOLLOW)
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if err != syscall.EOPNOTSUPP {
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t.Fatalf("Fchmodat: unexpected error: %v, expected EOPNOTSUPP", err)
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}
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}
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func TestMain(m *testing.M) {
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if os.Getenv("GO_DEATHSIG_PARENT") == "1" {
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deathSignalParent()
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} else if os.Getenv("GO_DEATHSIG_CHILD") == "1" {
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deathSignalChild()
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} else if os.Getenv("GO_SYSCALL_NOERROR") == "1" {
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syscallNoError()
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}
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os.Exit(m.Run())
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}
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func TestLinuxDeathSignal(t *testing.T) {
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if os.Getuid() != 0 {
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t.Skip("skipping root only test")
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}
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// Copy the test binary to a location that a non-root user can read/execute
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// after we drop privileges
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tempDir, err := ioutil.TempDir("", "TestDeathSignal")
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if err != nil {
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t.Fatalf("cannot create temporary directory: %v", err)
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}
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defer os.RemoveAll(tempDir)
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os.Chmod(tempDir, 0755)
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tmpBinary := filepath.Join(tempDir, filepath.Base(os.Args[0]))
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src, err := os.Open(os.Args[0])
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if err != nil {
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t.Fatalf("cannot open binary %q, %v", os.Args[0], err)
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}
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defer src.Close()
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dst, err := os.OpenFile(tmpBinary, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0755)
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if err != nil {
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t.Fatalf("cannot create temporary binary %q, %v", tmpBinary, err)
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}
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if _, err := io.Copy(dst, src); err != nil {
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t.Fatalf("failed to copy test binary to %q, %v", tmpBinary, err)
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}
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err = dst.Close()
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if err != nil {
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t.Fatalf("failed to close test binary %q, %v", tmpBinary, err)
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}
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cmd := exec.Command(tmpBinary)
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cmd.Env = append(os.Environ(), "GO_DEATHSIG_PARENT=1")
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chldStdin, err := cmd.StdinPipe()
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if err != nil {
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t.Fatalf("failed to create new stdin pipe: %v", err)
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}
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chldStdout, err := cmd.StdoutPipe()
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if err != nil {
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t.Fatalf("failed to create new stdout pipe: %v", err)
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}
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cmd.Stderr = os.Stderr
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err = cmd.Start()
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defer cmd.Wait()
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if err != nil {
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t.Fatalf("failed to start first child process: %v", err)
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}
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chldPipe := bufio.NewReader(chldStdout)
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if got, err := chldPipe.ReadString('\n'); got == "start\n" {
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syscall.Kill(cmd.Process.Pid, syscall.SIGTERM)
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go func() {
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time.Sleep(5 * time.Second)
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chldStdin.Close()
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}()
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want := "ok\n"
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if got, err = chldPipe.ReadString('\n'); got != want {
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t.Fatalf("expected %q, received %q, %v", want, got, err)
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}
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} else {
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t.Fatalf("did not receive start from child, received %q, %v", got, err)
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}
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}
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func deathSignalParent() {
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cmd := exec.Command(os.Args[0])
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cmd.Env = append(os.Environ(),
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"GO_DEATHSIG_PARENT=",
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"GO_DEATHSIG_CHILD=1",
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)
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cmd.Stdin = os.Stdin
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cmd.Stdout = os.Stdout
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attrs := syscall.SysProcAttr{
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Pdeathsig: syscall.SIGUSR1,
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// UID/GID 99 is the user/group "nobody" on RHEL/Fedora and is
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// unused on Ubuntu
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Credential: &syscall.Credential{Uid: 99, Gid: 99},
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}
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cmd.SysProcAttr = &attrs
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err := cmd.Start()
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if err != nil {
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fmt.Fprintf(os.Stderr, "death signal parent error: %v\n", err)
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os.Exit(1)
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}
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cmd.Wait()
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os.Exit(0)
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}
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func deathSignalChild() {
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c := make(chan os.Signal, 1)
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signal.Notify(c, syscall.SIGUSR1)
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go func() {
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<-c
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fmt.Println("ok")
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os.Exit(0)
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}()
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fmt.Println("start")
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buf := make([]byte, 32)
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os.Stdin.Read(buf)
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// We expected to be signaled before stdin closed
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fmt.Println("not ok")
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os.Exit(1)
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}
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func TestParseNetlinkMessage(t *testing.T) {
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for i, b := range [][]byte{
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{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,
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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,
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1, 127, 0, 0, 1, 230, 228, 31, 144, 32, 186, 155, 211, 185, 151, 209, 179, 128, 24, 1, 86,
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53, 119, 0, 0, 1, 1, 8, 10, 0, 17, 234, 12, 0, 17, 189, 126, 107, 106, 108, 107, 106, 13, 10,
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},
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{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,
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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,
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1, 127, 0, 0, 1, 237, 206, 31, 144, 73, 197, 128, 65, 250, 60, 192, 97, 128, 24, 1, 86, 253, 21, 0,
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0, 1, 1, 8, 10, 0, 51, 106, 89, 0, 51, 102, 198, 108, 104, 106, 108, 107, 104, 108, 107, 104, 10,
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},
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{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,
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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,
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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,
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10, 0, 52, 198, 200, 0, 51, 135, 232, 101, 115, 97, 103, 103, 10,
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},
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} {
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m, err := syscall.ParseNetlinkMessage(b)
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if err != syscall.EINVAL {
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t.Errorf("#%d: got %v; want EINVAL", i, err)
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}
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if m != nil {
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t.Errorf("#%d: got %v; want nil", i, m)
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}
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}
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}
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func TestSyscallNoError(t *testing.T) {
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// On Linux there are currently no syscalls which don't fail and return
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// a value larger than 0xfffffffffffff001 so we could test RawSyscall
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// vs. RawSyscallNoError on 64bit architectures.
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if unsafe.Sizeof(uintptr(0)) != 4 {
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t.Skip("skipping on non-32bit architecture")
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}
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// See https://golang.org/issue/35422
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// On MIPS, Linux returns whether the syscall had an error in a separate
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// register (R7), not using a negative return value as on other
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// architectures.
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if runtime.GOARCH == "mips" || runtime.GOARCH == "mipsle" {
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t.Skipf("skipping on %s", runtime.GOARCH)
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}
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if os.Getuid() != 0 {
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t.Skip("skipping root only test")
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}
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if syscall.Sys_GETEUID == 0 {
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t.Skip("skipping because there is no geteuid system call")
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}
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if runtime.GOOS == "android" {
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t.Skip("skipping on rooted android, see issue 27364")
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}
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// Copy the test binary to a location that a non-root user can read/execute
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// after we drop privileges
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tempDir, err := ioutil.TempDir("", "TestSyscallNoError")
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if err != nil {
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t.Fatalf("cannot create temporary directory: %v", err)
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}
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defer os.RemoveAll(tempDir)
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os.Chmod(tempDir, 0755)
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tmpBinary := filepath.Join(tempDir, filepath.Base(os.Args[0]))
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src, err := os.Open(os.Args[0])
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if err != nil {
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t.Fatalf("cannot open binary %q, %v", os.Args[0], err)
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}
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defer src.Close()
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dst, err := os.OpenFile(tmpBinary, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0755)
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if err != nil {
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t.Fatalf("cannot create temporary binary %q, %v", tmpBinary, err)
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}
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if _, err := io.Copy(dst, src); err != nil {
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t.Fatalf("failed to copy test binary to %q, %v", tmpBinary, err)
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}
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err = dst.Close()
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if err != nil {
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t.Fatalf("failed to close test binary %q, %v", tmpBinary, err)
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}
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uid := uint32(0xfffffffe)
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err = os.Chown(tmpBinary, int(uid), -1)
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if err != nil {
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t.Fatalf("failed to chown test binary %q, %v", tmpBinary, err)
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}
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err = os.Chmod(tmpBinary, 0755|os.ModeSetuid)
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if err != nil {
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t.Fatalf("failed to set setuid bit on test binary %q, %v", tmpBinary, err)
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}
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cmd := exec.Command(tmpBinary)
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cmd.Env = append(os.Environ(), "GO_SYSCALL_NOERROR=1")
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out, err := cmd.CombinedOutput()
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if err != nil {
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t.Fatalf("failed to start first child process: %v", err)
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}
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got := strings.TrimSpace(string(out))
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want := strconv.FormatUint(uint64(uid)+1, 10) + " / " +
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strconv.FormatUint(uint64(-uid), 10) + " / " +
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strconv.FormatUint(uint64(uid), 10)
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if got != want {
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if filesystemIsNoSUID(tmpBinary) {
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t.Skip("skipping test when temp dir is mounted nosuid")
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}
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// formatted so the values are aligned for easier comparison
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t.Errorf("expected %s,\ngot %s", want, got)
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}
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}
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// filesystemIsNoSUID reports whether the filesystem for the given
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// path is mounted nosuid.
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func filesystemIsNoSUID(path string) bool {
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var st syscall.Statfs_t
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if syscall.Statfs(path, &st) != nil {
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return false
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}
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return st.Flags&syscall.MS_NOSUID != 0
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}
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func syscallNoError() {
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// Test that the return value from SYS_GETEUID32 (which cannot fail)
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// doesn't get treated as an error (see https://golang.org/issue/22924)
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euid1, _, e := syscall.RawSyscall(syscall.Sys_GETEUID, 0, 0, 0)
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euid2, _ := syscall.RawSyscallNoError(syscall.Sys_GETEUID, 0, 0, 0)
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fmt.Println(uintptr(euid1), "/", int(e), "/", uintptr(euid2))
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os.Exit(0)
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}
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