runtime: log all thread stack traces during GODEBUG=crash on Unix

This extends https://golang.org/cl/2811, which only applied to Darwin
and GNU/Linux, to all Unix systems.

Fixes #9591.

Change-Id: Iec3fb438564ba2924b15b447c0480f87c0bfd009
Reviewed-on: https://go-review.googlesource.com/12661
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>

src/runtime/crash_unix_test.go

@@ -0,0 +1,135 @@
+// 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/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"syscall"
+	"testing"
+)
+
+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)
+	}
+
+	// We don't use executeTest because we need to kill the
+	// program while it is running.
+
+	testenv.MustHaveGoBuild(t)
+
+	checkStaleRuntime(t)
+
+	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("go", "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")
+	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++ {
+		}
+	}
+}
+`