blob: 42ae5ba89ca1ba9509f609364b2cd807b041cd98 [file] [log] [blame]
// Copyright 2020 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 zos && s390x
// +build zos,s390x
package unix_test
import (
"flag"
"fmt"
"io/ioutil"
"net"
"os"
"os/exec"
"path/filepath"
"runtime"
"strconv"
"syscall"
"testing"
"time"
"unsafe"
"golang.org/x/sys/unix"
)
// Tests that below functions, structures and constants are consistent
// on all Unix-like systems.
func _() {
// program scheduling priority functions and constants
var (
_ func(int, int, int) error = unix.Setpriority
_ func(int, int) (int, error) = unix.Getpriority
)
const (
_ int = unix.PRIO_USER
_ int = unix.PRIO_PROCESS
_ int = unix.PRIO_PGRP
)
// termios constants
const (
_ int = unix.TCIFLUSH
_ int = unix.TCIOFLUSH
_ int = unix.TCOFLUSH
)
// fcntl file locking structure and constants
var (
_ = unix.Flock_t{
Type: int16(0),
Whence: int16(0),
Start: int64(0),
Len: int64(0),
Pid: int32(0),
}
)
const (
_ = unix.F_GETLK
_ = unix.F_SETLK
_ = unix.F_SETLKW
)
}
func TestErrnoSignalName(t *testing.T) {
testErrors := []struct {
num syscall.Errno
name string
}{
{syscall.EPERM, "EDC5139I"},
{syscall.EINVAL, "EDC5121I"},
{syscall.ENOENT, "EDC5129I"},
}
for _, te := range testErrors {
t.Run(fmt.Sprintf("%d/%s", te.num, te.name), func(t *testing.T) {
e := unix.ErrnoName(te.num)
if e != te.name {
t.Errorf("ErrnoName(%d) returned %s, want %s", te.num, e, te.name)
}
})
}
testSignals := []struct {
num syscall.Signal
name string
}{
{syscall.SIGHUP, "SIGHUP"},
{syscall.SIGPIPE, "SIGPIPE"},
{syscall.SIGSEGV, "SIGSEGV"},
}
for _, ts := range testSignals {
t.Run(fmt.Sprintf("%d/%s", ts.num, ts.name), func(t *testing.T) {
s := unix.SignalName(ts.num)
if s != ts.name {
t.Errorf("SignalName(%d) returned %s, want %s", ts.num, s, ts.name)
}
})
}
}
func TestSignalNum(t *testing.T) {
testSignals := []struct {
name string
want syscall.Signal
}{
{"SIGHUP", syscall.SIGHUP},
{"SIGPIPE", syscall.SIGPIPE},
{"SIGSEGV", syscall.SIGSEGV},
{"NONEXISTS", 0},
}
for _, ts := range testSignals {
t.Run(fmt.Sprintf("%s/%d", ts.name, ts.want), func(t *testing.T) {
got := unix.SignalNum(ts.name)
if got != ts.want {
t.Errorf("SignalNum(%s) returned %d, want %d", ts.name, got, ts.want)
}
})
}
}
func TestFcntlInt(t *testing.T) {
t.Parallel()
file, err := ioutil.TempFile("", "TestFnctlInt")
if err != nil {
t.Fatal(err)
}
defer os.Remove(file.Name())
defer file.Close()
f := file.Fd()
flags, err := unix.FcntlInt(f, unix.F_GETFD, 0)
if err != nil {
t.Fatal(err)
}
if flags&unix.FD_CLOEXEC == 0 {
t.Errorf("flags %#x do not include FD_CLOEXEC", flags)
}
}
// TestFcntlFlock tests whether the file locking structure matches
// the calling convention of each kernel.
func TestFcntlFlock(t *testing.T) {
name := filepath.Join(os.TempDir(), "TestFcntlFlock")
fd, err := unix.Open(name, unix.O_CREAT|unix.O_RDWR|unix.O_CLOEXEC, 0)
if err != nil {
t.Fatalf("Open failed: %v", err)
}
defer unix.Unlink(name)
defer unix.Close(fd)
flock := unix.Flock_t{
Type: unix.F_RDLCK,
Start: 0, Len: 0, Whence: 1,
}
if err := unix.FcntlFlock(uintptr(fd), unix.F_GETLK, &flock); err != nil {
t.Fatalf("FcntlFlock failed: %v", err)
}
}
// TestPassFD tests passing a file descriptor over a Unix socket.
//
// This test involved both a parent and child process. The parent
// process is invoked as a normal test, with "go test", which then
// runs the child process by running the current test binary with args
// "-test.run=^TestPassFD$" and an environment variable used to signal
// that the test should become the child process instead.
func TestPassFD(t *testing.T) {
if runtime.GOOS == "darwin" && runtime.GOARCH == "arm64" {
t.Skip("cannot exec subprocess on iOS, skipping test")
}
if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
passFDChild()
return
}
if runtime.GOOS == "aix" {
// Unix network isn't properly working on AIX
// 7.2 with Technical Level < 2
out, err := exec.Command("oslevel", "-s").Output()
if err != nil {
t.Skipf("skipping on AIX because oslevel -s failed: %v", err)
}
if len(out) < len("7200-XX-ZZ-YYMM") { // AIX 7.2, Tech Level XX, Service Pack ZZ, date YYMM
t.Skip("skipping on AIX because oslevel -s hasn't the right length")
}
aixVer := string(out[:4])
tl, err := strconv.Atoi(string(out[5:7]))
if err != nil {
t.Skipf("skipping on AIX because oslevel -s output cannot be parsed: %v", err)
}
if aixVer < "7200" || (aixVer == "7200" && tl < 2) {
t.Skip("skipped on AIX versions previous to 7.2 TL 2")
}
}
tempDir, err := ioutil.TempDir("", "TestPassFD")
if err != nil {
t.Fatal(err)
}
defer os.RemoveAll(tempDir)
fds, err := unix.Socketpair(unix.AF_LOCAL, unix.SOCK_STREAM, 0)
if err != nil {
t.Fatalf("Socketpair: %v", err)
}
writeFile := os.NewFile(uintptr(fds[0]), "child-writes")
readFile := os.NewFile(uintptr(fds[1]), "parent-reads")
defer writeFile.Close()
defer readFile.Close()
cmd := exec.Command(os.Args[0], "-test.run=^TestPassFD$", "--", tempDir)
cmd.Env = []string{"GO_WANT_HELPER_PROCESS=1"}
if lp := os.Getenv("LD_LIBRARY_PATH"); lp != "" {
cmd.Env = append(cmd.Env, "LD_LIBRARY_PATH="+lp)
}
cmd.ExtraFiles = []*os.File{writeFile}
out, err := cmd.CombinedOutput()
if len(out) > 0 || err != nil {
t.Fatalf("child process: %q, %v", out, err)
}
c, err := net.FileConn(readFile)
if err != nil {
t.Fatalf("FileConn: %v", err)
}
defer c.Close()
uc, ok := c.(*net.UnixConn)
if !ok {
t.Fatalf("unexpected FileConn type; expected UnixConn, got %T", c)
}
buf := make([]byte, 32) // expect 1 byte
oob := make([]byte, 32) // expect 24 bytes
closeUnix := time.AfterFunc(5*time.Second, func() {
t.Logf("timeout reading from unix socket")
uc.Close()
})
_, oobn, _, _, err := uc.ReadMsgUnix(buf, oob)
if err != nil {
t.Fatalf("ReadMsgUnix: %v", err)
}
closeUnix.Stop()
scms, err := unix.ParseSocketControlMessage(oob[:oobn])
if err != nil {
t.Fatalf("ParseSocketControlMessage: %v", err)
}
if len(scms) != 1 {
t.Fatalf("expected 1 SocketControlMessage; got scms = %#v", scms)
}
scm := scms[0]
gotFds, err := unix.ParseUnixRights(&scm)
if err != nil {
t.Fatalf("unix.ParseUnixRights: %v", err)
}
if len(gotFds) != 1 {
t.Fatalf("wanted 1 fd; got %#v", gotFds)
}
f := os.NewFile(uintptr(gotFds[0]), "fd-from-child")
defer f.Close()
got, err := ioutil.ReadAll(f)
want := "Hello from child process!\n"
if string(got) != want {
t.Errorf("child process ReadAll: %q, %v; want %q", got, err, want)
}
}
// passFDChild is the child process used by TestPassFD.
func passFDChild() {
defer os.Exit(0)
// Look for our fd. It should be fd 3, but we work around an fd leak
// bug here (http://golang.org/issue/2603) to let it be elsewhere.
var uc *net.UnixConn
for fd := uintptr(3); fd <= 10; fd++ {
f := os.NewFile(fd, "unix-conn")
var ok bool
netc, _ := net.FileConn(f)
uc, ok = netc.(*net.UnixConn)
if ok {
break
}
}
if uc == nil {
fmt.Println("failed to find unix fd")
return
}
// Make a file f to send to our parent process on uc.
// We make it in tempDir, which our parent will clean up.
flag.Parse()
tempDir := flag.Arg(0)
f, err := ioutil.TempFile(tempDir, "")
if err != nil {
fmt.Printf("TempFile: %v", err)
return
}
f.Write([]byte("Hello from child process!\n"))
f.Seek(0, 0)
rights := unix.UnixRights(int(f.Fd()))
dummyByte := []byte("x")
n, oobn, err := uc.WriteMsgUnix(dummyByte, rights, nil)
if err != nil {
fmt.Printf("WriteMsgUnix: %v", err)
return
}
if n != 1 || oobn != len(rights) {
fmt.Printf("WriteMsgUnix = %d, %d; want 1, %d", n, oobn, len(rights))
return
}
}
// TestUnixRightsRoundtrip tests that UnixRights, ParseSocketControlMessage,
// and ParseUnixRights are able to successfully round-trip lists of file descriptors.
func TestUnixRightsRoundtrip(t *testing.T) {
testCases := [...][][]int{
{{42}},
{{1, 2}},
{{3, 4, 5}},
{{}},
{{1, 2}, {3, 4, 5}, {}, {7}},
}
for _, testCase := range testCases {
b := []byte{}
var n int
for _, fds := range testCase {
// Last assignment to n wins
n = len(b) + unix.CmsgLen(4*len(fds))
b = append(b, unix.UnixRights(fds...)...)
}
// Truncate b
b = b[:n]
scms, err := unix.ParseSocketControlMessage(b)
if err != nil {
t.Fatalf("ParseSocketControlMessage: %v", err)
}
if len(scms) != len(testCase) {
t.Fatalf("expected %v SocketControlMessage; got scms = %#v", len(testCase), scms)
}
for i, scm := range scms {
gotFds, err := unix.ParseUnixRights(&scm)
if err != nil {
t.Fatalf("ParseUnixRights: %v", err)
}
wantFds := testCase[i]
if len(gotFds) != len(wantFds) {
t.Fatalf("expected %v fds, got %#v", len(wantFds), gotFds)
}
for j, fd := range gotFds {
if fd != wantFds[j] {
t.Fatalf("expected fd %v, got %v", wantFds[j], fd)
}
}
}
}
}
func TestRlimit(t *testing.T) {
var rlimit, zero unix.Rlimit
err := unix.Getrlimit(unix.RLIMIT_NOFILE, &rlimit)
if err != nil {
t.Fatalf("Getrlimit: save failed: %v", err)
}
if zero == rlimit {
t.Fatalf("Getrlimit: save failed: got zero value %#v", rlimit)
}
set := rlimit
set.Cur = set.Max - 1
if runtime.GOOS == "darwin" && set.Cur > 10240 {
// The max file limit is 10240, even though
// the max returned by Getrlimit is 1<<63-1.
// This is OPEN_MAX in sys/syslimits.h.
set.Cur = 10240
}
err = unix.Setrlimit(unix.RLIMIT_NOFILE, &set)
if err != nil {
t.Fatalf("Setrlimit: set failed: %#v %v", set, err)
}
var get unix.Rlimit
err = unix.Getrlimit(unix.RLIMIT_NOFILE, &get)
if err != nil {
t.Fatalf("Getrlimit: get failed: %v", err)
}
set = rlimit
set.Cur = set.Max - 1
if set != get {
// Seems like Darwin requires some privilege to
// increase the soft limit of rlimit sandbox, though
// Setrlimit never reports an error.
switch runtime.GOOS {
case "darwin":
default:
t.Fatalf("Rlimit: change failed: wanted %#v got %#v", set, get)
}
}
err = unix.Setrlimit(unix.RLIMIT_NOFILE, &rlimit)
if err != nil {
t.Fatalf("Setrlimit: restore failed: %#v %v", rlimit, err)
}
}
func TestSeekFailure(t *testing.T) {
_, err := unix.Seek(-1, 0, 0)
if err == nil {
t.Fatalf("Seek(-1, 0, 0) did not fail")
}
str := err.Error() // used to crash on Linux
t.Logf("Seek: %v", str)
if str == "" {
t.Fatalf("Seek(-1, 0, 0) return error with empty message")
}
}
func TestSetsockoptString(t *testing.T) {
// should not panic on empty string, see issue #31277
err := unix.SetsockoptString(-1, 0, 0, "")
if err == nil {
t.Fatalf("SetsockoptString: did not fail")
}
}
func TestDup(t *testing.T) {
file, err := ioutil.TempFile("", "TestDup")
if err != nil {
t.Fatalf("Tempfile failed: %v", err)
}
defer os.Remove(file.Name())
defer file.Close()
f := int(file.Fd())
newFd, err := unix.Dup(f)
if err != nil {
t.Fatalf("Dup: %v", err)
}
// Create and reserve a file descriptor.
// Dup2 automatically closes it before reusing it.
nullFile, err := os.Open("/dev/null")
if err != nil {
t.Fatal(err)
}
dupFd := int(file.Fd())
err = unix.Dup2(newFd, dupFd)
if err != nil {
t.Fatalf("Dup2: %v", err)
}
// Keep the dummy file open long enough to not be closed in
// its finalizer.
runtime.KeepAlive(nullFile)
b1 := []byte("Test123")
b2 := make([]byte, 7)
_, err = unix.Write(dupFd, b1)
if err != nil {
t.Fatalf("Write to dup2 fd failed: %v", err)
}
_, err = unix.Seek(f, 0, 0)
if err != nil {
t.Fatalf("Seek failed: %v", err)
}
_, err = unix.Read(f, b2)
if err != nil {
t.Fatalf("Read back failed: %v", err)
}
if string(b1) != string(b2) {
t.Errorf("Dup: stdout write not in file, expected %v, got %v", string(b1), string(b2))
}
}
func TestGetwd(t *testing.T) {
fd, err := os.Open(".")
if err != nil {
t.Fatalf("Open .: %s", err)
}
defer fd.Close()
// Directory list for test. Do not worry if any are symlinks or do not
// exist on some common unix desktop environments. That will be checked.
dirs := []string{"/", "/usr/bin", "/etc", "/var", "/opt"}
switch runtime.GOOS {
case "android":
dirs = []string{"/", "/system/bin"}
case "darwin":
switch runtime.GOARCH {
case "arm64":
d1, err := ioutil.TempDir("", "d1")
if err != nil {
t.Fatalf("TempDir: %v", err)
}
d2, err := ioutil.TempDir("", "d2")
if err != nil {
t.Fatalf("TempDir: %v", err)
}
dirs = []string{d1, d2}
}
}
oldwd := os.Getenv("PWD")
for _, d := range dirs {
// Check whether d exists, is a dir and that d's path does not contain a symlink
fi, err := os.Stat(d)
if err != nil || !fi.IsDir() {
t.Logf("Test dir %s stat error (%v) or not a directory, skipping", d, err)
continue
}
check, err := filepath.EvalSymlinks(d)
if err != nil || check != d {
t.Logf("Test dir %s (%s) is symlink or other error (%v), skipping", d, check, err)
continue
}
err = os.Chdir(d)
if err != nil {
t.Fatalf("Chdir: %v", err)
}
pwd, err := unix.Getwd()
if err != nil {
t.Fatalf("Getwd in %s: %s", d, err)
}
os.Setenv("PWD", oldwd)
err = fd.Chdir()
if err != nil {
// We changed the current directory and cannot go back.
// Don't let the tests continue; they'll scribble
// all over some other directory.
fmt.Fprintf(os.Stderr, "fchdir back to dot failed: %s\n", err)
os.Exit(1)
}
if pwd != d {
t.Fatalf("Getwd returned %q want %q", pwd, d)
}
}
}
func TestMkdev(t *testing.T) {
major := uint32(42)
minor := uint32(7)
dev := unix.Mkdev(major, minor)
if unix.Major(dev) != major {
t.Errorf("Major(%#x) == %d, want %d", dev, unix.Major(dev), major)
}
if unix.Minor(dev) != minor {
t.Errorf("Minor(%#x) == %d, want %d", dev, unix.Minor(dev), minor)
}
}
// mktmpfifo creates a temporary FIFO and provides a cleanup function.
func mktmpfifo(t *testing.T) (*os.File, func()) {
err := unix.Mkfifo("fifo", 0666)
if err != nil {
t.Fatalf("mktmpfifo: failed to create FIFO: %v", err)
}
f, err := os.OpenFile("fifo", os.O_RDWR, 0666)
if err != nil {
os.Remove("fifo")
t.Fatalf("mktmpfifo: failed to open FIFO: %v", err)
}
return f, func() {
f.Close()
os.Remove("fifo")
}
}
// utilities taken from os/os_test.go
func touch(t *testing.T, name string) {
f, err := os.Create(name)
if err != nil {
t.Fatal(err)
}
if err := f.Close(); err != nil {
t.Fatal(err)
}
}
// chtmpdir changes the working directory to a new temporary directory and
// provides a cleanup function. Used when PWD is read-only.
func chtmpdir(t *testing.T) func() {
oldwd, err := os.Getwd()
if err != nil {
t.Fatalf("chtmpdir: %v", err)
}
d, err := ioutil.TempDir("", "test")
if err != nil {
t.Fatalf("chtmpdir: %v", err)
}
if err := os.Chdir(d); err != nil {
t.Fatalf("chtmpdir: %v", err)
}
return func() {
if err := os.Chdir(oldwd); err != nil {
t.Fatalf("chtmpdir: %v", err)
}
os.RemoveAll(d)
}
}
func TestMountUnmount(t *testing.T) {
// use an available fs
var buffer struct {
header unix.W_Mnth
fsinfo [64]unix.W_Mntent
}
fsCount, err := unix.W_Getmntent_A((*byte)(unsafe.Pointer(&buffer)), int(unsafe.Sizeof(buffer)))
if err != nil {
t.Fatalf("W_Getmntent_A returns with error: %s", err.Error())
} else if fsCount == 0 {
t.Fatalf("W_Getmntent_A returns no entries")
}
var fs string
var fstype string
var mountpoint string
var available bool = false
for i := 0; i < fsCount; i++ {
err = unix.Unmount(unix.ByteSliceToString(buffer.fsinfo[i].Mountpoint[:]), unix.MTM_RDWR)
if err != nil {
// Unmount and Mount require elevated privilege
// If test is run without such permission, skip test
if err == unix.EPERM {
t.Logf("Permission denied for Unmount. Skipping test (Errno2: %X)", unix.Errno2())
return
} else if err == unix.EBUSY {
continue
} else {
t.Fatalf("Unmount returns with error: %s", err.Error())
}
} else {
available = true
fs = unix.ByteSliceToString(buffer.fsinfo[i].Fsname[:])
fstype = unix.ByteSliceToString(buffer.fsinfo[i].Fstname[:])
mountpoint = unix.ByteSliceToString(buffer.fsinfo[i].Mountpoint[:])
t.Logf("using file system = %s; fstype = %s and mountpoint = %s\n", fs, fstype, mountpoint)
break
}
}
if !available {
t.Fatalf("No filesystem available")
}
// test unmount
buffer.header = unix.W_Mnth{}
fsCount, err = unix.W_Getmntent_A((*byte)(unsafe.Pointer(&buffer)), int(unsafe.Sizeof(buffer)))
if err != nil {
t.Fatalf("W_Getmntent_A returns with error: %s", err.Error())
}
for i := 0; i < fsCount; i++ {
if unix.ByteSliceToString(buffer.fsinfo[i].Fsname[:]) == fs {
t.Fatalf("File system found after unmount")
}
}
// test mount
err = unix.Mount(fs, mountpoint, fstype, unix.MTM_RDWR, "")
if err != nil {
t.Fatalf("Mount returns with error: %s", err.Error())
}
buffer.header = unix.W_Mnth{}
fsCount, err = unix.W_Getmntent_A((*byte)(unsafe.Pointer(&buffer)), int(unsafe.Sizeof(buffer)))
if err != nil {
t.Fatalf("W_Getmntent_A returns with error: %s", err.Error())
}
fsMounted := false
for i := 0; i < fsCount; i++ {
if unix.ByteSliceToString(buffer.fsinfo[i].Fsname[:]) == fs &&
unix.ByteSliceToString(buffer.fsinfo[i].Mountpoint[:]) == mountpoint {
fsMounted = true
}
}
if !fsMounted {
t.Fatalf("%s not mounted after Mount()", fs)
}
}
func TestChroot(t *testing.T) {
// create temp dir and tempfile 1
tempDir, err := ioutil.TempDir("", "TestChroot")
if err != nil {
t.Fatalf("TempDir: %s", err.Error())
}
defer os.RemoveAll(tempDir)
f, err := ioutil.TempFile(tempDir, "chroot_test_file")
if err != nil {
t.Fatalf("TempFile: %s", err.Error())
}
// chroot temp dir
err = unix.Chroot(tempDir)
// Chroot requires elevated privilege
// If test is run without such permission, skip test
if err == unix.EPERM {
t.Logf("Denied permission for Chroot. Skipping test (Errno2: %X)", unix.Errno2())
return
} else if err != nil {
t.Fatalf("Chroot: %s", err.Error())
}
// check if tempDir contains test file
files, err := ioutil.ReadDir("/")
if err != nil {
t.Fatalf("ReadDir: %s", err.Error())
}
found := false
for _, file := range files {
if file.Name() == filepath.Base(f.Name()) {
found = true
break
}
}
if !found {
t.Fatalf("Temp file not found in temp dir")
}
}
func TestFlock(t *testing.T) {
if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
defer os.Exit(0)
if len(os.Args) != 3 {
fmt.Printf("bad argument")
return
}
fn := os.Args[2]
f, err := os.OpenFile(fn, os.O_RDWR, 0755)
if err != nil {
fmt.Printf("%s", err.Error())
return
}
err = unix.Flock(int(f.Fd()), unix.LOCK_EX|unix.LOCK_NB)
// if the lock we are trying should be locked, ignore EAGAIN error
// otherwise, report all errors
if err != nil && err != unix.EAGAIN {
fmt.Printf("%s", err.Error())
}
} else {
// create temp dir and tempfile 1
tempDir, err := ioutil.TempDir("", "TestFlock")
if err != nil {
t.Fatalf("TempDir: %s", err.Error())
}
defer os.RemoveAll(tempDir)
f, err := ioutil.TempFile(tempDir, "flock_test_file")
if err != nil {
t.Fatalf("TempFile: %s", err.Error())
}
fd := int(f.Fd())
/* Test Case 1
* Try acquiring an occupied lock from another process
*/
err = unix.Flock(fd, unix.LOCK_EX)
if err != nil {
t.Fatalf("Flock: %s", err.Error())
}
cmd := exec.Command(os.Args[0], "-test.run=TestFlock", f.Name())
cmd.Env = append(os.Environ(), "GO_WANT_HELPER_PROCESS=1")
out, err := cmd.CombinedOutput()
if len(out) > 0 || err != nil {
t.Fatalf("child process: %q, %v", out, err)
}
err = unix.Flock(fd, unix.LOCK_UN)
if err != nil {
t.Fatalf("Flock: %s", err.Error())
}
/* Test Case 2
* Try locking with Flock and FcntlFlock for same file
*/
err = unix.Flock(fd, unix.LOCK_EX)
if err != nil {
t.Fatalf("Flock: %s", err.Error())
}
flock := unix.Flock_t{
Type: int16(unix.F_WRLCK),
Whence: int16(0),
Start: int64(0),
Len: int64(0),
Pid: int32(unix.Getppid()),
}
err = unix.FcntlFlock(f.Fd(), unix.F_SETLK, &flock)
if err != nil {
t.Fatalf("FcntlFlock: %s", err.Error())
}
}
}
func TestSelect(t *testing.T) {
for {
n, err := unix.Select(0, nil, nil, nil, &unix.Timeval{Sec: 0, Usec: 0})
if err == unix.EINTR {
t.Logf("Select interrupted")
continue
} else if err != nil {
t.Fatalf("Select: %v", err)
}
if n != 0 {
t.Fatalf("Select: got %v ready file descriptors, expected 0", n)
}
break
}
dur := 250 * time.Millisecond
var took time.Duration
for {
// On some platforms (e.g. Linux), the passed-in timeval is
// updated by select(2). Make sure to reset to the full duration
// in case of an EINTR.
tv := unix.NsecToTimeval(int64(dur))
start := time.Now()
n, err := unix.Select(0, nil, nil, nil, &tv)
took = time.Since(start)
if err == unix.EINTR {
t.Logf("Select interrupted after %v", took)
continue
} else if err != nil {
t.Fatalf("Select: %v", err)
}
if n != 0 {
t.Fatalf("Select: got %v ready file descriptors, expected 0", n)
}
break
}
// On some BSDs the actual timeout might also be slightly less than the requested.
// Add an acceptable margin to avoid flaky tests.
if took < dur*2/3 {
t.Errorf("Select: got %v timeout, expected at least %v", took, dur)
}
rr, ww, err := os.Pipe()
if err != nil {
t.Fatal(err)
}
defer rr.Close()
defer ww.Close()
if _, err := ww.Write([]byte("HELLO GOPHER")); err != nil {
t.Fatal(err)
}
rFdSet := &unix.FdSet{}
fd := int(rr.Fd())
rFdSet.Set(fd)
for {
n, err := unix.Select(fd+1, rFdSet, nil, nil, nil)
if err == unix.EINTR {
t.Log("Select interrupted")
continue
} else if err != nil {
t.Fatalf("Select: %v", err)
}
if n != 1 {
t.Fatalf("Select: got %v ready file descriptors, expected 1", n)
}
break
}
}