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Source file src/runtime/crash_unix_test.go

Documentation: runtime

  // Copyright 2012 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.
  
  // +build darwin dragonfly freebsd linux netbsd openbsd solaris
  
  package runtime_test
  
  import (
  	"bytes"
  	"internal/testenv"
  	"io"
  	"io/ioutil"
  	"os"
  	"os/exec"
  	"path/filepath"
  	"runtime"
  	"strings"
  	"syscall"
  	"testing"
  )
  
  // sigquit is the signal to send to kill a hanging testdata program.
  // Send SIGQUIT to get a stack trace.
  var sigquit = syscall.SIGQUIT
  
  func init() {
  	if runtime.Sigisblocked(int(syscall.SIGQUIT)) {
  		// We can't use SIGQUIT to kill subprocesses because
  		// it's blocked. Use SIGKILL instead. See issue
  		// #19196 for an example of when this happens.
  		sigquit = syscall.SIGKILL
  	}
  }
  
  func TestCrashDumpsAllThreads(t *testing.T) {
  	switch runtime.GOOS {
  	case "darwin", "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "solaris":
  	default:
  		t.Skipf("skipping; not supported on %v", runtime.GOOS)
  	}
  
  	if runtime.Sigisblocked(int(syscall.SIGQUIT)) {
  		t.Skip("skipping; SIGQUIT is blocked, see golang.org/issue/19196")
  	}
  
  	// We don't use executeTest because we need to kill the
  	// program while it is running.
  
  	testenv.MustHaveGoBuild(t)
  
  	checkStaleRuntime(t)
  
  	t.Parallel()
  
  	dir, err := ioutil.TempDir("", "go-build")
  	if err != nil {
  		t.Fatalf("failed to create temp directory: %v", err)
  	}
  	defer os.RemoveAll(dir)
  
  	if err := ioutil.WriteFile(filepath.Join(dir, "main.go"), []byte(crashDumpsAllThreadsSource), 0666); err != nil {
  		t.Fatalf("failed to create Go file: %v", err)
  	}
  
  	cmd := exec.Command(testenv.GoToolPath(t), "build", "-o", "a.exe")
  	cmd.Dir = dir
  	out, err := testEnv(cmd).CombinedOutput()
  	if err != nil {
  		t.Fatalf("building source: %v\n%s", err, out)
  	}
  
  	cmd = exec.Command(filepath.Join(dir, "a.exe"))
  	cmd = testEnv(cmd)
  	cmd.Env = append(cmd.Env, "GOTRACEBACK=crash")
  
  	// Set GOGC=off. Because of golang.org/issue/10958, the tight
  	// loops in the test program are not preemptible. If GC kicks
  	// in, it may lock up and prevent main from saying it's ready.
  	newEnv := []string{}
  	for _, s := range cmd.Env {
  		if !strings.HasPrefix(s, "GOGC=") {
  			newEnv = append(newEnv, s)
  		}
  	}
  	cmd.Env = append(newEnv, "GOGC=off")
  
  	var outbuf bytes.Buffer
  	cmd.Stdout = &outbuf
  	cmd.Stderr = &outbuf
  
  	rp, wp, err := os.Pipe()
  	if err != nil {
  		t.Fatal(err)
  	}
  	cmd.ExtraFiles = []*os.File{wp}
  
  	if err := cmd.Start(); err != nil {
  		t.Fatalf("starting program: %v", err)
  	}
  
  	if err := wp.Close(); err != nil {
  		t.Logf("closing write pipe: %v", err)
  	}
  	if _, err := rp.Read(make([]byte, 1)); err != nil {
  		t.Fatalf("reading from pipe: %v", err)
  	}
  
  	if err := cmd.Process.Signal(syscall.SIGQUIT); err != nil {
  		t.Fatalf("signal: %v", err)
  	}
  
  	// No point in checking the error return from Wait--we expect
  	// it to fail.
  	cmd.Wait()
  
  	// We want to see a stack trace for each thread.
  	// Before https://golang.org/cl/2811 running threads would say
  	// "goroutine running on other thread; stack unavailable".
  	out = outbuf.Bytes()
  	n := bytes.Count(out, []byte("main.loop("))
  	if n != 4 {
  		t.Errorf("found %d instances of main.loop; expected 4", n)
  		t.Logf("%s", out)
  	}
  }
  
  const crashDumpsAllThreadsSource = `
  package main
  
  import (
  	"fmt"
  	"os"
  	"runtime"
  )
  
  func main() {
  	const count = 4
  	runtime.GOMAXPROCS(count + 1)
  
  	chans := make([]chan bool, count)
  	for i := range chans {
  		chans[i] = make(chan bool)
  		go loop(i, chans[i])
  	}
  
  	// Wait for all the goroutines to start executing.
  	for _, c := range chans {
  		<-c
  	}
  
  	// Tell our parent that all the goroutines are executing.
  	if _, err := os.NewFile(3, "pipe").WriteString("x"); err != nil {
  		fmt.Fprintf(os.Stderr, "write to pipe failed: %v\n", err)
  		os.Exit(2)
  	}
  
  	select {}
  }
  
  func loop(i int, c chan bool) {
  	close(c)
  	for {
  		for j := 0; j < 0x7fffffff; j++ {
  		}
  	}
  }
  `
  
  func TestPanicSystemstack(t *testing.T) {
  	// Test that GOTRACEBACK=crash prints both the system and user
  	// stack of other threads.
  
  	// The GOTRACEBACK=crash handler takes 0.1 seconds even if
  	// it's not writing a core file and potentially much longer if
  	// it is. Skip in short mode.
  	if testing.Short() {
  		t.Skip("Skipping in short mode (GOTRACEBACK=crash is slow)")
  	}
  
  	if runtime.Sigisblocked(int(syscall.SIGQUIT)) {
  		t.Skip("skipping; SIGQUIT is blocked, see golang.org/issue/19196")
  	}
  
  	t.Parallel()
  	cmd := exec.Command(os.Args[0], "testPanicSystemstackInternal")
  	cmd = testEnv(cmd)
  	cmd.Env = append(cmd.Env, "GOTRACEBACK=crash")
  	pr, pw, err := os.Pipe()
  	if err != nil {
  		t.Fatal("creating pipe: ", err)
  	}
  	cmd.Stderr = pw
  	if err := cmd.Start(); err != nil {
  		t.Fatal("starting command: ", err)
  	}
  	defer cmd.Process.Wait()
  	defer cmd.Process.Kill()
  	if err := pw.Close(); err != nil {
  		t.Log("closing write pipe: ", err)
  	}
  	defer pr.Close()
  
  	// Wait for "x\nx\n" to indicate readiness.
  	buf := make([]byte, 4)
  	_, err = io.ReadFull(pr, buf)
  	if err != nil || string(buf) != "x\nx\n" {
  		t.Fatal("subprocess failed; output:\n", string(buf))
  	}
  
  	// Send SIGQUIT.
  	if err := cmd.Process.Signal(syscall.SIGQUIT); err != nil {
  		t.Fatal("signaling subprocess: ", err)
  	}
  
  	// Get traceback.
  	tb, err := ioutil.ReadAll(pr)
  	if err != nil {
  		t.Fatal("reading traceback from pipe: ", err)
  	}
  
  	// Traceback should have two testPanicSystemstackInternal's
  	// and two blockOnSystemStackInternal's.
  	if bytes.Count(tb, []byte("testPanicSystemstackInternal")) != 2 {
  		t.Fatal("traceback missing user stack:\n", string(tb))
  	} else if bytes.Count(tb, []byte("blockOnSystemStackInternal")) != 2 {
  		t.Fatal("traceback missing system stack:\n", string(tb))
  	}
  }
  
  func init() {
  	if len(os.Args) >= 2 && os.Args[1] == "testPanicSystemstackInternal" {
  		// Get two threads running on the system stack with
  		// something recognizable in the stack trace.
  		runtime.GOMAXPROCS(2)
  		go testPanicSystemstackInternal()
  		testPanicSystemstackInternal()
  	}
  }
  
  func testPanicSystemstackInternal() {
  	runtime.BlockOnSystemStack()
  	os.Exit(1) // Should be unreachable.
  }
  
  func TestSignalExitStatus(t *testing.T) {
  	testenv.MustHaveGoBuild(t)
  	exe, err := buildTestProg(t, "testprog")
  	if err != nil {
  		t.Fatal(err)
  	}
  	err = testEnv(exec.Command(exe, "SignalExitStatus")).Run()
  	if err == nil {
  		t.Error("test program succeeded unexpectedly")
  	} else if ee, ok := err.(*exec.ExitError); !ok {
  		t.Errorf("error (%v) has type %T; expected exec.ExitError", err, err)
  	} else if ws, ok := ee.Sys().(syscall.WaitStatus); !ok {
  		t.Errorf("error.Sys (%v) has type %T; expected syscall.WaitStatus", ee.Sys(), ee.Sys())
  	} else if !ws.Signaled() || ws.Signal() != syscall.SIGTERM {
  		t.Errorf("got %v; expected SIGTERM", ee)
  	}
  }
  
  func TestSignalIgnoreSIGTRAP(t *testing.T) {
  	output := runTestProg(t, "testprognet", "SignalIgnoreSIGTRAP")
  	want := "OK\n"
  	if output != want {
  		t.Fatalf("want %s, got %s\n", want, output)
  	}
  }
  
  func TestSignalDuringExec(t *testing.T) {
  	switch runtime.GOOS {
  	case "darwin", "dragonfly", "freebsd", "linux", "netbsd", "openbsd":
  	default:
  		t.Skipf("skipping test on %s", runtime.GOOS)
  	}
  	output := runTestProg(t, "testprognet", "SignalDuringExec")
  	want := "OK\n"
  	if output != want {
  		t.Fatalf("want %s, got %s\n", want, output)
  	}
  }
  

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