internal/poll: inject a hook into the runtime finalizer to count the closed pipes

Fixes #48066

Change-Id: Icd6974dfcc496c054bb096e5d70de6e135984517
Reviewed-on: https://go-review.googlesource.com/c/go/+/349774
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>

diff --git a/src/internal/poll/splice_linux_test.go b/src/internal/poll/splice_linux_test.go
index deac5c37596b463eb398f503a506d4aa7689b3fe..8c4363886e7e3f015d2e323041f3e2557448a538 100644 (file)
--- a/src/internal/poll/splice_linux_test.go
+++ b/src/internal/poll/splice_linux_test.go
@@ -6,40 +6,48 @@ package poll_test
 
 import (
        "internal/poll"
-       "internal/syscall/unix"
        "runtime"
-       "syscall"
+       "sync"
+       "sync/atomic"
        "testing"
        "time"
 )
 
-// checkPipes returns true if all pipes are closed properly, false otherwise.
-func checkPipes(fds []int) bool {
-       for _, fd := range fds {
-               // Check if each pipe fd has been closed.
-               _, _, errno := syscall.Syscall(unix.FcntlSyscall, uintptr(fd), syscall.F_GETPIPE_SZ, 0)
-               if errno == 0 {
-                       return false
+var closeHook atomic.Value // func(fd int)
+
+func init() {
+       closeFunc := poll.CloseFunc
+       poll.CloseFunc = func(fd int) (err error) {
+               if v := closeHook.Load(); v != nil {
+                       if hook := v.(func(int)); hook != nil {
+                               hook(fd)
+                       }
                }
+               return closeFunc(fd)
        }
-       return true
 }
 
 func TestSplicePipePool(t *testing.T) {
        const N = 64
        var (
-               p   *poll.SplicePipe
-               ps  []*poll.SplicePipe
-               fds []int
-               err error
+               p          *poll.SplicePipe
+               ps         []*poll.SplicePipe
+               allFDs     []int
+               pendingFDs sync.Map // fd → struct{}{}
+               err        error
        )
+
+       closeHook.Store(func(fd int) { pendingFDs.Delete(fd) })
+       t.Cleanup(func() { closeHook.Store((func(int))(nil)) })
+
        for i := 0; i < N; i++ {
                p, _, err = poll.GetPipe()
                if err != nil {
-                       t.Skip("failed to create pipe, skip this test")
+                       t.Skipf("failed to create pipe due to error(%v), skip this test", err)
                }
                _, pwfd := poll.GetPipeFds(p)
-               fds = append(fds, pwfd)
+               allFDs = append(allFDs, pwfd)
+               pendingFDs.Store(pwfd, struct{}{})
                ps = append(ps, p)
        }
        for _, p = range ps {
@@ -62,19 +70,21 @@ func TestSplicePipePool(t *testing.T) {
        for {
                runtime.GC()
                time.Sleep(10 * time.Millisecond)
-               if checkPipes(fds) {
+
+               // Detect whether all pipes are closed properly.
+               var leakedFDs []int
+               pendingFDs.Range(func(k, v interface{}) bool {
+                       leakedFDs = append(leakedFDs, k.(int))
+                       return true
+               })
+               if len(leakedFDs) == 0 {
                        break
                }
+
                select {
                case <-expiredTime.C:
-                       t.Logf("descriptors to check: %v", fds)
-                       for _, fd := range fds {
-                               _, _, errno := syscall.Syscall(unix.FcntlSyscall, uintptr(fd), syscall.F_GETPIPE_SZ, 0)
-                               if errno == 0 {
-                                       t.Errorf("descriptor %d still open", fd)
-                               }
-                       }
-                       t.Fatal("at least one pipe is still open")
+                       t.Logf("all descriptors: %v", allFDs)
+                       t.Fatalf("leaked descriptors: %v", leakedFDs)
                default:
                }
        }