1 files changed, 474 insertions, 0 deletions
diff --git a/src/os/pipe_test.go b/src/os/pipe_test.go
new file mode 100644
index 0000000..b98e538
--- /dev/null
+++ b/src/os/pipe_test.go
@@ -0,0 +1,474 @@
+// 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.
+
+// Test broken pipes on Unix systems.
+// +build !plan9,!js
+
+package os_test
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"internal/testenv"
+	"io"
+	"io/fs"
+	"os"
+	osexec "os/exec"
+	"os/signal"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+	"testing"
+	"time"
+)
+
+func TestEPIPE(t *testing.T) {
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := r.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	expect := syscall.EPIPE
+	if runtime.GOOS == "windows" {
+		// 232 is Windows error code ERROR_NO_DATA, "The pipe is being closed".
+		expect = syscall.Errno(232)
+	}
+	// Every time we write to the pipe we should get an EPIPE.
+	for i := 0; i < 20; i++ {
+		_, err = w.Write([]byte("hi"))
+		if err == nil {
+			t.Fatal("unexpected success of Write to broken pipe")
+		}
+		if pe, ok := err.(*fs.PathError); ok {
+			err = pe.Err
+		}
+		if se, ok := err.(*os.SyscallError); ok {
+			err = se.Err
+		}
+		if err != expect {
+			t.Errorf("iteration %d: got %v, expected %v", i, err, expect)
+		}
+	}
+}
+
+func TestStdPipe(t *testing.T) {
+	switch runtime.GOOS {
+	case "windows":
+		t.Skip("Windows doesn't support SIGPIPE")
+	}
+	testenv.MustHaveExec(t)
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := r.Close(); err != nil {
+		t.Fatal(err)
+	}
+	// Invoke the test program to run the test and write to a closed pipe.
+	// If sig is false:
+	// writing to stdout or stderr should cause an immediate SIGPIPE;
+	// writing to descriptor 3 should fail with EPIPE and then exit 0.
+	// If sig is true:
+	// all writes should fail with EPIPE and then exit 0.
+	for _, sig := range []bool{false, true} {
+		for dest := 1; dest < 4; dest++ {
+			cmd := osexec.Command(os.Args[0], "-test.run", "TestStdPipeHelper")
+			cmd.Stdout = w
+			cmd.Stderr = w
+			cmd.ExtraFiles = []*os.File{w}
+			cmd.Env = append(os.Environ(), fmt.Sprintf("GO_TEST_STD_PIPE_HELPER=%d", dest))
+			if sig {
+				cmd.Env = append(cmd.Env, "GO_TEST_STD_PIPE_HELPER_SIGNAL=1")
+			}
+			if err := cmd.Run(); err == nil {
+				if !sig && dest < 3 {
+					t.Errorf("unexpected success of write to closed pipe %d sig %t in child", dest, sig)
+				}
+			} else if ee, ok := err.(*osexec.ExitError); !ok {
+				t.Errorf("unexpected exec error type %T: %v", err, err)
+			} else if ws, ok := ee.Sys().(syscall.WaitStatus); !ok {
+				t.Errorf("unexpected wait status type %T: %v", ee.Sys(), ee.Sys())
+			} else if ws.Signaled() && ws.Signal() == syscall.SIGPIPE {
+				if sig || dest > 2 {
+					t.Errorf("unexpected SIGPIPE signal for descriptor %d sig %t", dest, sig)
+				}
+			} else {
+				t.Errorf("unexpected exit status %v for descriptor %d sig %t", err, dest, sig)
+			}
+		}
+	}
+
+	// Test redirecting stdout but not stderr.  Issue 40076.
+	cmd := osexec.Command(os.Args[0], "-test.run", "TestStdPipeHelper")
+	cmd.Stdout = w
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	cmd.Env = append(os.Environ(), "GO_TEST_STD_PIPE_HELPER=1")
+	if err := cmd.Run(); err == nil {
+		t.Errorf("unexpected success of write to closed stdout")
+	} else if ee, ok := err.(*osexec.ExitError); !ok {
+		t.Errorf("unexpected exec error type %T: %v", err, err)
+	} else if ws, ok := ee.Sys().(syscall.WaitStatus); !ok {
+		t.Errorf("unexpected wait status type %T: %v", ee.Sys(), ee.Sys())
+	} else if !ws.Signaled() || ws.Signal() != syscall.SIGPIPE {
+		t.Errorf("unexpected exit status %v for write to closed stdout", err)
+	}
+	if output := stderr.Bytes(); len(output) > 0 {
+		t.Errorf("unexpected output on stderr: %s", output)
+	}
+}
+
+// This is a helper for TestStdPipe. It's not a test in itself.
+func TestStdPipeHelper(t *testing.T) {
+	if os.Getenv("GO_TEST_STD_PIPE_HELPER_SIGNAL") != "" {
+		signal.Notify(make(chan os.Signal, 1), syscall.SIGPIPE)
+	}
+	switch os.Getenv("GO_TEST_STD_PIPE_HELPER") {
+	case "1":
+		os.Stdout.Write([]byte("stdout"))
+	case "2":
+		os.Stderr.Write([]byte("stderr"))
+	case "3":
+		if _, err := os.NewFile(3, "3").Write([]byte("3")); err == nil {
+			os.Exit(3)
+		}
+	default:
+		t.Skip("skipping test helper")
+	}
+	// For stdout/stderr, we should have crashed with a broken pipe error.
+	// The caller will be looking for that exit status,
+	// so just exit normally here to cause a failure in the caller.
+	// For descriptor 3, a normal exit is expected.
+	os.Exit(0)
+}
+
+func testClosedPipeRace(t *testing.T, read bool) {
+	switch runtime.GOOS {
+	case "freebsd":
+		t.Skip("FreeBSD does not use the poller; issue 19093")
+	}
+
+	limit := 1
+	if !read {
+		// Get the amount we have to write to overload a pipe
+		// with no reader.
+		limit = 131073
+		if b, err := os.ReadFile("/proc/sys/fs/pipe-max-size"); err == nil {
+			if i, err := strconv.Atoi(strings.TrimSpace(string(b))); err == nil {
+				limit = i + 1
+			}
+		}
+		t.Logf("using pipe write limit of %d", limit)
+	}
+
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer r.Close()
+	defer w.Close()
+
+	// Close the read end of the pipe in a goroutine while we are
+	// writing to the write end, or vice-versa.
+	go func() {
+		// Give the main goroutine a chance to enter the Read or
+		// Write call. This is sloppy but the test will pass even
+		// if we close before the read/write.
+		time.Sleep(20 * time.Millisecond)
+
+		var err error
+		if read {
+			err = r.Close()
+		} else {
+			err = w.Close()
+		}
+		if err != nil {
+			t.Error(err)
+		}
+	}()
+
+	b := make([]byte, limit)
+	if read {
+		_, err = r.Read(b[:])
+	} else {
+		_, err = w.Write(b[:])
+	}
+	if err == nil {
+		t.Error("I/O on closed pipe unexpectedly succeeded")
+	} else if pe, ok := err.(*fs.PathError); !ok {
+		t.Errorf("I/O on closed pipe returned unexpected error type %T; expected fs.PathError", pe)
+	} else if pe.Err != fs.ErrClosed {
+		t.Errorf("got error %q but expected %q", pe.Err, fs.ErrClosed)
+	} else {
+		t.Logf("I/O returned expected error %q", err)
+	}
+}
+
+func TestClosedPipeRaceRead(t *testing.T) {
+	testClosedPipeRace(t, true)
+}
+
+func TestClosedPipeRaceWrite(t *testing.T) {
+	testClosedPipeRace(t, false)
+}
+
+// Issue 20915: Reading on nonblocking fd should not return "waiting
+// for unsupported file type." Currently it returns EAGAIN; it is
+// possible that in the future it will simply wait for data.
+func TestReadNonblockingFd(t *testing.T) {
+	switch runtime.GOOS {
+	case "windows":
+		t.Skip("Windows doesn't support SetNonblock")
+	}
+	if os.Getenv("GO_WANT_READ_NONBLOCKING_FD") == "1" {
+		fd := syscallDescriptor(os.Stdin.Fd())
+		syscall.SetNonblock(fd, true)
+		defer syscall.SetNonblock(fd, false)
+		_, err := os.Stdin.Read(make([]byte, 1))
+		if err != nil {
+			if perr, ok := err.(*fs.PathError); !ok || perr.Err != syscall.EAGAIN {
+				t.Fatalf("read on nonblocking stdin got %q, should have gotten EAGAIN", err)
+			}
+		}
+		os.Exit(0)
+	}
+
+	testenv.MustHaveExec(t)
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer r.Close()
+	defer w.Close()
+	cmd := osexec.Command(os.Args[0], "-test.run="+t.Name())
+	cmd.Env = append(os.Environ(), "GO_WANT_READ_NONBLOCKING_FD=1")
+	cmd.Stdin = r
+	output, err := cmd.CombinedOutput()
+	t.Logf("%s", output)
+	if err != nil {
+		t.Errorf("child process failed: %v", err)
+	}
+}
+
+func TestCloseWithBlockingReadByNewFile(t *testing.T) {
+	var p [2]syscallDescriptor
+	err := syscall.Pipe(p[:])
+	if err != nil {
+		t.Fatal(err)
+	}
+	// os.NewFile returns a blocking mode file.
+	testCloseWithBlockingRead(t, os.NewFile(uintptr(p[0]), "reader"), os.NewFile(uintptr(p[1]), "writer"))
+}
+
+func TestCloseWithBlockingReadByFd(t *testing.T) {
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Calling Fd will put the file into blocking mode.
+	_ = r.Fd()
+	testCloseWithBlockingRead(t, r, w)
+}
+
+// Test that we don't let a blocking read prevent a close.
+func testCloseWithBlockingRead(t *testing.T, r, w *os.File) {
+	defer r.Close()
+	defer w.Close()
+
+	c1, c2 := make(chan bool), make(chan bool)
+	var wg sync.WaitGroup
+
+	wg.Add(1)
+	go func(c chan bool) {
+		defer wg.Done()
+		// Give the other goroutine a chance to enter the Read
+		// or Write call. This is sloppy but the test will
+		// pass even if we close before the read/write.
+		time.Sleep(20 * time.Millisecond)
+
+		if err := r.Close(); err != nil {
+			t.Error(err)
+		}
+		close(c)
+	}(c1)
+
+	wg.Add(1)
+	go func(c chan bool) {
+		defer wg.Done()
+		var b [1]byte
+		_, err := r.Read(b[:])
+		close(c)
+		if err == nil {
+			t.Error("I/O on closed pipe unexpectedly succeeded")
+		}
+		if pe, ok := err.(*fs.PathError); ok {
+			err = pe.Err
+		}
+		if err != io.EOF && err != fs.ErrClosed {
+			t.Errorf("got %v, expected EOF or closed", err)
+		}
+	}(c2)
+
+	for c1 != nil || c2 != nil {
+		select {
+		case <-c1:
+			c1 = nil
+			// r.Close has completed, but the blocking Read
+			// is hanging. Close the writer to unblock it.
+			w.Close()
+		case <-c2:
+			c2 = nil
+		case <-time.After(1 * time.Second):
+			switch {
+			case c1 != nil && c2 != nil:
+				t.Error("timed out waiting for Read and Close")
+				w.Close()
+			case c1 != nil:
+				t.Error("timed out waiting for Close")
+			case c2 != nil:
+				t.Error("timed out waiting for Read")
+			default:
+				t.Error("impossible case")
+			}
+		}
+	}
+
+	wg.Wait()
+}
+
+// Issue 24164, for pipes.
+func TestPipeEOF(t *testing.T) {
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+
+		defer func() {
+			if err := w.Close(); err != nil {
+				t.Errorf("error closing writer: %v", err)
+			}
+		}()
+
+		for i := 0; i < 3; i++ {
+			time.Sleep(10 * time.Millisecond)
+			_, err := fmt.Fprintf(w, "line %d\n", i)
+			if err != nil {
+				t.Errorf("error writing to fifo: %v", err)
+				return
+			}
+		}
+		time.Sleep(10 * time.Millisecond)
+	}()
+
+	defer wg.Wait()
+
+	done := make(chan bool)
+	go func() {
+		defer close(done)
+
+		defer func() {
+			if err := r.Close(); err != nil {
+				t.Errorf("error closing reader: %v", err)
+			}
+		}()
+
+		rbuf := bufio.NewReader(r)
+		for {
+			b, err := rbuf.ReadBytes('\n')
+			if err == io.EOF {
+				break
+			}
+			if err != nil {
+				t.Error(err)
+				return
+			}
+			t.Logf("%s\n", bytes.TrimSpace(b))
+		}
+	}()
+
+	select {
+	case <-done:
+		// Test succeeded.
+	case <-time.After(time.Second):
+		t.Error("timed out waiting for read")
+		// Close the reader to force the read to complete.
+		r.Close()
+	}
+}
+
+// Issue 24481.
+func TestFdRace(t *testing.T) {
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer r.Close()
+	defer w.Close()
+
+	var wg sync.WaitGroup
+	call := func() {
+		defer wg.Done()
+		w.Fd()
+	}
+
+	const tries = 100
+	for i := 0; i < tries; i++ {
+		wg.Add(1)
+		go call()
+	}
+	wg.Wait()
+}
+
+func TestFdReadRace(t *testing.T) {
+	t.Parallel()
+
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer r.Close()
+	defer w.Close()
+
+	c := make(chan bool)
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		var buf [10]byte
+		r.SetReadDeadline(time.Now().Add(time.Minute))
+		c <- true
+		if _, err := r.Read(buf[:]); os.IsTimeout(err) {
+			t.Error("read timed out")
+		}
+	}()
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		<-c
+		// Give the other goroutine a chance to enter the Read.
+		// It doesn't matter if this occasionally fails, the test
+		// will still pass, it just won't test anything.
+		time.Sleep(10 * time.Millisecond)
+		r.Fd()
+
+		// The bug was that Fd would hang until Read timed out.
+		// If the bug is fixed, then closing r here will cause
+		// the Read to exit before the timeout expires.
+		r.Close()
+	}()
+
+	wg.Wait()
+}