exec: add test to verify net package's epoll fd doesn't go to child

R=rsc
CC=golang-dev
https://golang.org/cl/5490075

diff --git a/src/pkg/os/exec/exec_test.go b/src/pkg/os/exec/exec_test.go
index d26127c7af2584e1356e75263eda68ada3880c36..4cd346a68b09902ede60e933e3f0b755dfe9e31e 100644 (file)
--- a/src/pkg/os/exec/exec_test.go
+++ b/src/pkg/os/exec/exec_test.go
@@ -10,6 +10,7 @@ import (
        "fmt"
        "io"
        "io/ioutil"
+       "net"
        "os"
        "runtime"
        "strconv"
@@ -146,6 +147,15 @@ func TestExtraFiles(t *testing.T) {
                t.Logf("no operating system support; skipping")
                return
        }
+
+       // Force network usage, to verify the epoll (or whatever) fd
+       // doesn't leak to the child,
+       ln, err := net.Listen("tcp", "127.0.0.1:0")
+       if err != nil {
+               t.Fatal(err)
+       }
+       defer ln.Close()
+
        tf, err := ioutil.TempFile("", "")
        if err != nil {
                t.Fatalf("TempFile: %v", err)
@@ -167,7 +177,7 @@ func TestExtraFiles(t *testing.T) {
        c.ExtraFiles = []*os.File{tf}
        bs, err := c.CombinedOutput()
        if err != nil {
-               t.Fatalf("CombinedOutput: %v", err)
+               t.Fatalf("CombinedOutput: %v; output %q", err, bs)
        }
        if string(bs) != text {
                t.Errorf("got %q; want %q", string(bs), text)
@@ -246,6 +256,29 @@ func TestHelperProcess(*testing.T) {
                        fmt.Printf("ReadAll from fd 3: %v", err)
                        os.Exit(1)
                }
+               // TODO(bradfitz,iant): the rest of this test is disabled
+               // for now. remove this block once 5494061 is in.
+               {
+                       os.Stderr.Write(bs)
+                       os.Exit(0)
+               }
+               // Now verify that there are no other open fds.
+               var files []*os.File
+               for wantfd := os.Stderr.Fd() + 2; wantfd <= 100; wantfd++ {
+                       f, err := os.Open(os.Args[0])
+                       if err != nil {
+                               fmt.Printf("error opening file with expected fd %d: %v", wantfd, err)
+                               os.Exit(1)
+                       }
+                       if got := f.Fd(); got != wantfd {
+                               fmt.Printf("leaked parent file. fd = %d; want %d", got, wantfd)
+                               os.Exit(1)
+                       }
+                       files = append(files, f)
+               }
+               for _, f := range files {
+                       f.Close()
+               }
                os.Stderr.Write(bs)
        case "exit":
                n, _ := strconv.Atoi(args[0])