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// 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 darwin || dragonfly || freebsd || (linux && !android) || netbsd || openbsd
package os_test
import (
"errors"
"internal/syscall/unix"
"internal/testenv"
"io/fs"
"os"
"path/filepath"
"strconv"
"sync"
"syscall"
"testing"
)
func TestFifoEOF(t *testing.T) {
t.Parallel()
dir := t.TempDir()
fifoName := filepath.Join(dir, "fifo")
if err := syscall.Mkfifo(fifoName, 0600); err != nil {
t.Fatal(err)
}
// Per https://pubs.opengroup.org/onlinepubs/9699919799/functions/open.html#tag_16_357_03:
//
// - “If O_NONBLOCK is clear, an open() for reading-only shall block the
// calling thread until a thread opens the file for writing. An open() for
// writing-only shall block the calling thread until a thread opens the file
// for reading.”
//
// In order to unblock both open calls, we open the two ends of the FIFO
// simultaneously in separate goroutines.
rc := make(chan *os.File, 1)
go func() {
r, err := os.Open(fifoName)
if err != nil {
t.Error(err)
}
rc <- r
}()
w, err := os.OpenFile(fifoName, os.O_WRONLY, 0)
if err != nil {
t.Error(err)
}
r := <-rc
if t.Failed() {
if r != nil {
r.Close()
}
if w != nil {
w.Close()
}
return
}
testPipeEOF(t, r, w)
}
// Issue #59545.
func TestNonPollable(t *testing.T) {
if testing.Short() {
t.Skip("skipping test with tight loops in short mode")
}
// We need to open a non-pollable file.
// This is almost certainly Linux-specific,
// but if other systems have non-pollable files,
// we can add them here.
const nonPollable = "/dev/net/tun"
f, err := os.OpenFile(nonPollable, os.O_RDWR, 0)
if err != nil {
if errors.Is(err, fs.ErrNotExist) || errors.Is(err, fs.ErrPermission) || testenv.SyscallIsNotSupported(err) {
t.Skipf("can't open %q: %v", nonPollable, err)
}
t.Fatal(err)
}
f.Close()
// On a Linux laptop, before the problem was fixed,
// this test failed about 50% of the time with this
// number of iterations.
// It takes about 1/2 second when it passes.
const attempts = 20000
start := make(chan bool)
var wg sync.WaitGroup
wg.Add(1)
defer wg.Wait()
go func() {
defer wg.Done()
close(start)
for i := 0; i < attempts; i++ {
f, err := os.OpenFile(nonPollable, os.O_RDWR, 0)
if err != nil {
t.Error(err)
return
}
if err := f.Close(); err != nil {
t.Error(err)
return
}
}
}()
dir := t.TempDir()
<-start
for i := 0; i < attempts; i++ {
name := filepath.Join(dir, strconv.Itoa(i))
if err := syscall.Mkfifo(name, 0o600); err != nil {
t.Fatal(err)
}
// The problem only occurs if we use O_NONBLOCK here.
rd, err := os.OpenFile(name, os.O_RDONLY|syscall.O_NONBLOCK, 0o600)
if err != nil {
t.Fatal(err)
}
wr, err := os.OpenFile(name, os.O_WRONLY|syscall.O_NONBLOCK, 0o600)
if err != nil {
t.Fatal(err)
}
const msg = "message"
if _, err := wr.Write([]byte(msg)); err != nil {
if errors.Is(err, syscall.EAGAIN) || errors.Is(err, syscall.ENOBUFS) {
t.Logf("ignoring write error %v", err)
rd.Close()
wr.Close()
continue
}
t.Fatalf("write to fifo %d failed: %v", i, err)
}
if _, err := rd.Read(make([]byte, len(msg))); err != nil {
if errors.Is(err, syscall.EAGAIN) || errors.Is(err, syscall.ENOBUFS) {
t.Logf("ignoring read error %v", err)
rd.Close()
wr.Close()
continue
}
t.Fatalf("read from fifo %d failed; %v", i, err)
}
if err := rd.Close(); err != nil {
t.Fatal(err)
}
if err := wr.Close(); err != nil {
t.Fatal(err)
}
}
}
// Issue 60211.
func TestOpenFileNonBlocking(t *testing.T) {
exe, err := os.Executable()
if err != nil {
t.Skipf("can't find executable: %v", err)
}
f, err := os.OpenFile(exe, os.O_RDONLY|syscall.O_NONBLOCK, 0666)
if err != nil {
t.Fatal(err)
}
defer f.Close()
nonblock, err := unix.IsNonblock(int(f.Fd()))
if err != nil {
t.Fatal(err)
}
if !nonblock {
t.Errorf("file opened with O_NONBLOCK but in blocking mode")
}
}
func TestNewFileNonBlocking(t *testing.T) {
var p [2]int
if err := syscall.Pipe(p[:]); err != nil {
t.Fatal(err)
}
if err := syscall.SetNonblock(p[0], true); err != nil {
t.Fatal(err)
}
f := os.NewFile(uintptr(p[0]), "pipe")
nonblock, err := unix.IsNonblock(p[0])
if err != nil {
t.Fatal(err)
}
if !nonblock {
t.Error("pipe blocking after NewFile")
}
fd := f.Fd()
if fd != uintptr(p[0]) {
t.Errorf("Fd returned %d, want %d", fd, p[0])
}
nonblock, err = unix.IsNonblock(p[0])
if err != nil {
t.Fatal(err)
}
if !nonblock {
t.Error("pipe blocking after Fd")
}
}
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