1 files changed, 134 insertions, 0 deletions
diff --git a/src/syscall/exec_pdeathsig_test.go b/src/syscall/exec_pdeathsig_test.go
new file mode 100644
index 0000000..96ae27b
--- /dev/null
+++ b/src/syscall/exec_pdeathsig_test.go
@@ -0,0 +1,134 @@
+// 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.
+
+//go:build freebsd || linux
+
+package syscall_test
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"os/signal"
+	"path/filepath"
+	"syscall"
+	"testing"
+	"time"
+)
+
+func TestDeathSignal(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 := os.MkdirTemp("", "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 = append(os.Environ(), "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 = append(os.Environ(),
+		"GO_DEATHSIG_PARENT=",
+		"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)
+}