unix: make solaris syscall tests less flaky

Fixes golang/go#58259

Change-Id: I1e8a83ed6ee3be8165c771b81a3cbdd474216c02
Reviewed-on: https://go-review.googlesource.com/c/sys/+/465055
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>

Author: nshalman

unix/syscall_internal_solaris_test.go

@@ -28,6 +28,40 @@ func (e *EventPort) checkInternals(t *testing.T, fds, paths, cookies, pending in
 	}
 }
 
+// getOneRetry wraps EventPort.GetOne which in turn wraps a syscall that can be
+// interrupted causing us to receive EINTR.
+// To prevent our tests from flaking, we retry the syscall until it works
+// rather than get unexpected results in our tests.
+func getOneRetry(t *testing.T, p *EventPort, timeout *Timespec) (e *PortEvent, err error) {
+	t.Helper()
+	for {
+		e, err = p.GetOne(timeout)
+		if err != EINTR {
+			break
+		}
+	}
+	return e, err
+}
+
+// getRetry wraps EventPort.Get which in turn wraps a syscall that can be
+// interrupted causing us to receive EINTR.
+// To prevent our tests from flaking, we retry the syscall until it works
+// rather than get unexpected results in our tests.
+func getRetry(t *testing.T, p *EventPort, s []PortEvent, min int, timeout *Timespec) (n int, err error) {
+	t.Helper()
+	for {
+		n, err = p.Get(s, min, timeout)
+		if err != EINTR {
+			break
+		}
+		// If we did get EINTR, make sure we got 0 events
+		if n != 0 {
+			t.Fatalf("EventPort.Get returned events on EINTR.\ngot: %d\nexpected: 0", n)
+		}
+	}
+	return n, err
+}
+
 // Regression test for DissociatePath returning ENOENT
 // This test is intended to create a linear worst
 // case scenario of events being associated and
@@ -143,7 +177,7 @@ func TestEventPortDissociateAlreadyGone(t *testing.T) {
 	runtime.GC()
 
 	// Before the fix, this would cause a nil pointer exception
-	e, err := port.GetOne(nil)
+	e, err := getOneRetry(t, port, nil)
 	if err != nil {
 		t.Errorf("failed to get an event: %v", err)
 	}
@@ -152,7 +186,7 @@ func TestEventPortDissociateAlreadyGone(t *testing.T) {
 		t.Errorf(`expected "cookie1", got "%v"`, e.Cookie)
 	}
 	// Make sure that a cookie of the same value doesn't cause removal from the paths map incorrectly
-	e, err = port.GetOne(nil)
+	e, err = getOneRetry(t, port, nil)
 	if err != nil {
 		t.Errorf("failed to get an event: %v", err)
 	}
@@ -167,7 +201,7 @@ func TestEventPortDissociateAlreadyGone(t *testing.T) {
 	}
 	// Event has fired, but until processed it should still be in the map
 	port.checkInternals(t, 0, 1, 1, 1)
-	e, err = port.GetOne(nil)
+	e, err = getOneRetry(t, port, nil)
 	if err != nil {
 		t.Errorf("failed to get an event: %v", err)
 	}
@@ -221,12 +255,12 @@ func TestEventPortGetAfterClose(t *testing.T) {
 	port.paths = nil
 	port.cookies = nil
 	// Ensure that we get back reasonable errors rather than panic
-	_, err = port.GetOne(nil)
+	_, err = getOneRetry(t, port, nil)
 	if err == nil || err.Error() != "this EventPort is already closed" {
 		t.Errorf("didn't receive expected error of 'this EventPort is already closed'; got: %v", err)
 	}
 	events := make([]PortEvent, 2)
-	n, err = port.Get(events, 1, nil)
+	n, err = getRetry(t, port, events, 1, nil)
 	if n != 0 {
 		t.Errorf("expected to get back 0 events, got %d", n)
 	}

unix/syscall_solaris_test.go

@@ -18,6 +18,40 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+// getOneRetry wraps EventPort.GetOne which in turn wraps a syscall that can be
+// interrupted causing us to receive EINTR.
+// To prevent our tests from flaking, we retry the syscall until it works
+// rather than get unexpected results in our tests.
+func getOneRetry(t *testing.T, p *unix.EventPort, timeout *unix.Timespec) (e *unix.PortEvent, err error) {
+	t.Helper()
+	for {
+		e, err = p.GetOne(timeout)
+		if err != unix.EINTR {
+			break
+		}
+	}
+	return e, err
+}
+
+// getRetry wraps EventPort.Get which in turn wraps a syscall that can be
+// interrupted causing us to receive EINTR.
+// To prevent our tests from flaking, we retry the syscall until it works
+// rather than get unexpected results in our tests.
+func getRetry(t *testing.T, p *unix.EventPort, s []unix.PortEvent, min int, timeout *unix.Timespec) (n int, err error) {
+	t.Helper()
+	for {
+		n, err = p.Get(s, min, timeout)
+		if err != unix.EINTR {
+			break
+		}
+		// If we did get EINTR, make sure we got 0 events
+		if n != 0 {
+			t.Fatalf("EventPort.Get returned events on EINTR.\ngot: %d\nexpected: 0", n)
+		}
+	}
+	return n, err
+}
+
 func TestStatvfs(t *testing.T) {
 	if err := unix.Statvfs("", nil); err == nil {
 		t.Fatal(`Statvfs("") expected failure`)
@@ -84,13 +118,13 @@ func TestBasicEventPort(t *testing.T) {
 	bs := []byte{42}
 	tmpfile.Write(bs)
 	timeout := new(unix.Timespec)
-	timeout.Sec = 1
-	pevent, err := port.GetOne(timeout)
+	timeout.Nsec = 100
+	pevent, err := getOneRetry(t, port, timeout)
 	if err == unix.ETIME {
 		t.Errorf("GetOne timed out: %v", err)
 	}
 	if err != nil {
-		t.Errorf("GetOne failed: %v", err)
+		t.Fatalf("GetOne failed: %v", err)
 	}
 	if pevent.Path != path {
 		t.Errorf("Path mismatch: %v != %v", pevent.Path, path)
@@ -135,13 +169,13 @@ func TestEventPortFds(t *testing.T) {
 		t.Errorf("Pending() failed: %v, %v", n, err)
 	}
 	timeout := new(unix.Timespec)
-	timeout.Sec = 1
-	pevent, err := port.GetOne(timeout)
+	timeout.Nsec = 100
+	pevent, err := getOneRetry(t, port, timeout)
 	if err == unix.ETIME {
 		t.Errorf("GetOne timed out: %v", err)
 	}
 	if err != nil {
-		t.Errorf("GetOne failed: %v", err)
+		t.Fatalf("GetOne failed: %v", err)
 	}
 	if pevent.Fd != fd {
 		t.Errorf("Fd mismatch: %v != %v", pevent.Fd, fd)
@@ -181,26 +215,24 @@ func TestEventPortErrors(t *testing.T) {
 	}
 	timeout := new(unix.Timespec)
 	timeout.Nsec = 1
-	_, err = port.GetOne(timeout)
+	_, err = getOneRetry(t, port, timeout)
 	if err != unix.ETIME {
-		// See https://go.dev/issue/58259
-		// Perhaps we sometimes get EINTR ???
 		t.Errorf("port.GetOne(%v) returned error %v, want %v", timeout, err, unix.ETIME)
 	}
 	err = port.DissociateFd(uintptr(0))
 	if err == nil {
 		t.Errorf("unexpected success dissociating unassociated fd")
 	}
 	events := make([]unix.PortEvent, 4)
-	_, err = port.Get(events, 5, nil)
+	_, err = getRetry(t, port, events, 5, nil)
 	if err == nil {
 		t.Errorf("unexpected success calling Get with min greater than len of slice")
 	}
-	_, err = port.Get(nil, 1, nil)
+	_, err = getRetry(t, port, nil, 1, nil)
 	if err == nil {
 		t.Errorf("unexpected success calling Get with nil slice")
 	}
-	_, err = port.Get(nil, 0, nil)
+	_, err = getRetry(t, port, nil, 0, nil)
 	if err == nil {
 		t.Errorf("unexpected success calling Get with nil slice")
 	}
@@ -232,7 +264,13 @@ func ExamplePortEvent() {
 	w.Write(bs)
 	timeout := new(unix.Timespec)
 	timeout.Sec = 1
-	pevent, err := port.GetOne(timeout)
+	var pevent *unix.PortEvent
+	for {
+		pevent, err = port.GetOne(timeout)
+		if err != unix.EINTR {
+			break
+		}
+	}
 	if err != nil {
 		fmt.Printf("didn't get the expected event: %v\n", err)
 	}
@@ -278,7 +316,7 @@ func TestPortEventSlices(t *testing.T) {
 	timeout := new(unix.Timespec)
 	timeout.Nsec = 1
 	events := make([]unix.PortEvent, 4)
-	n, err = port.Get(events, 3, timeout)
+	n, err = getRetry(t, port, events, 3, timeout)
 	if err != nil {
 		t.Errorf("Get failed: %v", err)
 	}
@@ -291,7 +329,7 @@ func TestPortEventSlices(t *testing.T) {
 			t.Errorf("unexpected event. got %v, expected %v", p.Events, unix.FILE_DELETE)
 		}
 	}
-	n, err = port.Get(events, 3, timeout)
+	n, err = getRetry(t, port, events, 3, timeout)
 	if err != unix.ETIME {
 		t.Errorf("unexpected error. got %v, expected %v", err, unix.ETIME)
 	}
@@ -314,7 +352,7 @@ func TestPortEventSlices(t *testing.T) {
 	bs := []byte{41}
 	w.Write(bs)
 
-	n, err = port.Get(events, 1, timeout)
+	n, err = getRetry(t, port, events, 1, timeout)
 	if err != nil {
 		t.Errorf("Get failed: %v", err)
 	}