diff options
Diffstat (limited to 'libgo/go/os/exec')
| -rw-r--r-- | libgo/go/os/exec/exec_linux_test.go | 45 | ||||
| -rw-r--r-- | libgo/go/os/exec/exec_test.go | 106 | ||||
| -rw-r--r-- | libgo/go/os/exec/read3.go | 99 |
3 files changed, 170 insertions, 80 deletions
diff --git a/libgo/go/os/exec/exec_linux_test.go b/libgo/go/os/exec/exec_linux_test.go new file mode 100644 index 0000000..6f85020 --- /dev/null +++ b/libgo/go/os/exec/exec_linux_test.go @@ -0,0 +1,45 @@ +// 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. + +// +build linux,cgo + +// On systems that use glibc, calling malloc can create a new arena, +// and creating a new arena can read /sys/devices/system/cpu/online. +// If we are using cgo, we will call malloc when creating a new thread. +// That can break TestExtraFiles if we create a new thread that creates +// a new arena and opens the /sys file while we are checking for open +// file descriptors. Work around the problem by creating threads up front. +// See issue 25628. + +package exec_test + +import ( + "os" + "sync" + "syscall" + "time" +) + +func init() { + if os.Getenv("GO_WANT_HELPER_PROCESS") != "1" { + return + } + + // Start some threads. 10 is arbitrary but intended to be enough + // to ensure that the code won't have to create any threads itself. + // In particular this should be more than the number of threads + // the garbage collector might create. + const threads = 10 + + var wg sync.WaitGroup + wg.Add(threads) + ts := syscall.NsecToTimespec((100 * time.Microsecond).Nanoseconds()) + for i := 0; i < threads; i++ { + go func() { + defer wg.Done() + syscall.Nanosleep(&ts, nil) + }() + } + wg.Wait() +} diff --git a/libgo/go/os/exec/exec_test.go b/libgo/go/os/exec/exec_test.go index dce66c5..dafbc64 100644 --- a/libgo/go/os/exec/exec_test.go +++ b/libgo/go/os/exec/exec_test.go @@ -488,25 +488,6 @@ func numOpenFDsAndroid(t *testing.T) (n int, lsof []byte) { return bytes.Count(lsof, []byte("\n")), lsof } -// basefds returns the number of expected file descriptors -// to be present in a process at start. -// stdin, stdout, stderr, epoll/kqueue, epoll/kqueue pipe, maybe testlog -func basefds() uintptr { - n := os.Stderr.Fd() + 1 - // The poll (epoll/kqueue) descriptor can be numerically - // either between stderr and the testlog-fd, or after - // testlog-fd. - for poll.IsPollDescriptor(n) { - n++ - } - for _, arg := range os.Args { - if strings.HasPrefix(arg, "-test.testlogfile=") { - n++ - } - } - return n -} - func TestExtraFilesFDShuffle(t *testing.T) { t.Skip("flaky test; see https://golang.org/issue/5780") switch runtime.GOOS { @@ -622,6 +603,7 @@ func TestExtraFiles(t *testing.T) { } testenv.MustHaveExec(t) + testenv.MustHaveGoBuild(t) if runtime.GOOS == "windows" { t.Skipf("skipping test on %q", runtime.GOOS) @@ -676,7 +658,31 @@ func TestExtraFiles(t *testing.T) { t.Fatalf("Seek: %v", err) } - c := helperCommand(t, "read3") + tempdir := t.TempDir() + exe := filepath.Join(tempdir, "read3.exe") + + c := exec.Command(testenv.GoToolPath(t), "build", "-o", exe, "read3.go") + // Build the test without cgo, so that C library functions don't + // open descriptors unexpectedly. See issue 25628. + c.Env = append(os.Environ(), "CGO_ENABLED=0") + if output, err := c.CombinedOutput(); err != nil { + t.Logf("go build -o %s read3.go\n%s", exe, output) + t.Fatalf("go build failed: %v", err) + } + + // Use a deadline to try to get some output even if the program hangs. + ctx := context.Background() + if deadline, ok := t.Deadline(); ok { + // Leave a 20% grace period to flush output, which may be large on the + // linux/386 builders because we're running the subprocess under strace. + deadline = deadline.Add(-time.Until(deadline) / 5) + + var cancel context.CancelFunc + ctx, cancel = context.WithDeadline(ctx, deadline) + defer cancel() + } + + c = exec.CommandContext(ctx, exe) var stdout, stderr bytes.Buffer c.Stdout = &stdout c.Stderr = &stderr @@ -757,17 +763,6 @@ func TestHelperProcess(*testing.T) { } defer os.Exit(0) - // Determine which command to use to display open files. - ofcmd := "lsof" - switch runtime.GOOS { - case "dragonfly", "freebsd", "netbsd", "openbsd": - ofcmd = "fstat" - case "plan9": - ofcmd = "/bin/cat" - case "aix": - ofcmd = "procfiles" - } - args := os.Args for len(args) > 0 { if args[0] == "--" { @@ -841,55 +836,6 @@ func TestHelperProcess(*testing.T) { os.Exit(1) } os.Exit(0) - case "read3": // read fd 3 - fd3 := os.NewFile(3, "fd3") - bs, err := ioutil.ReadAll(fd3) - if err != nil { - fmt.Printf("ReadAll from fd 3: %v", err) - os.Exit(1) - } - // Now verify that there are no other open fds. - var files []*os.File - for wantfd := basefds() + 1; wantfd <= 100; wantfd++ { - if poll.IsPollDescriptor(wantfd) { - continue - } - 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\n", got, wantfd) - var args []string - switch runtime.GOOS { - case "plan9": - args = []string{fmt.Sprintf("/proc/%d/fd", os.Getpid())} - case "aix": - args = []string{fmt.Sprint(os.Getpid())} - default: - args = []string{"-p", fmt.Sprint(os.Getpid())} - } - cmd := exec.Command(ofcmd, args...) - out, err := cmd.CombinedOutput() - if err != nil { - fmt.Fprintf(os.Stderr, "%s failed: %v\n", strings.Join(cmd.Args, " "), err) - } - fmt.Printf("%s", out) - os.Exit(1) - } - files = append(files, f) - } - for _, f := range files { - f.Close() - } - // Referring to fd3 here ensures that it is not - // garbage collected, and therefore closed, while - // executing the wantfd loop above. It doesn't matter - // what we do with fd3 as long as we refer to it; - // closing it is the easy choice. - fd3.Close() - os.Stdout.Write(bs) case "exit": n, _ := strconv.Atoi(args[0]) os.Exit(n) diff --git a/libgo/go/os/exec/read3.go b/libgo/go/os/exec/read3.go new file mode 100644 index 0000000..25d732a --- /dev/null +++ b/libgo/go/os/exec/read3.go @@ -0,0 +1,99 @@ +// 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. + +// +build ignore + +// This is a test program that verifies that it can read from +// descriptor 3 and that no other descriptors are open. +// This is not done via TestHelperProcess and GO_WANT_HELPER_PROCESS +// because we want to ensure that this program does not use cgo, +// because C libraries can open file descriptors behind our backs +// and confuse the test. See issue 25628. +package main + +import ( + "fmt" + "internal/poll" + "io/ioutil" + "os" + "os/exec" + "runtime" + "strings" +) + +func main() { + fd3 := os.NewFile(3, "fd3") + bs, err := ioutil.ReadAll(fd3) + if err != nil { + fmt.Printf("ReadAll from fd 3: %v\n", err) + os.Exit(1) + } + + // Now verify that there are no other open fds. + // stdin == 0 + // stdout == 1 + // stderr == 2 + // descriptor from parent == 3 + // All descriptors 4 and up should be available, + // except for any used by the network poller. + var files []*os.File + for wantfd := uintptr(4); wantfd <= 100; wantfd++ { + if poll.IsPollDescriptor(wantfd) { + continue + } + 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\n", got, wantfd) + fdfile := fmt.Sprintf("/proc/self/fd/%d", wantfd) + link, err := os.Readlink(fdfile) + fmt.Printf("readlink(%q) = %q, %v\n", fdfile, link, err) + var args []string + switch runtime.GOOS { + case "plan9": + args = []string{fmt.Sprintf("/proc/%d/fd", os.Getpid())} + case "aix": + args = []string{fmt.Sprint(os.Getpid())} + default: + args = []string{"-p", fmt.Sprint(os.Getpid())} + } + + // Determine which command to use to display open files. + ofcmd := "lsof" + switch runtime.GOOS { + case "dragonfly", "freebsd", "netbsd", "openbsd": + ofcmd = "fstat" + case "plan9": + ofcmd = "/bin/cat" + case "aix": + ofcmd = "procfiles" + } + + cmd := exec.Command(ofcmd, args...) + out, err := cmd.CombinedOutput() + if err != nil { + fmt.Fprintf(os.Stderr, "%s failed: %v\n", strings.Join(cmd.Args, " "), err) + } + fmt.Printf("%s", out) + os.Exit(1) + } + files = append(files, f) + } + + for _, f := range files { + f.Close() + } + + // Referring to fd3 here ensures that it is not + // garbage collected, and therefore closed, while + // executing the wantfd loop above. It doesn't matter + // what we do with fd3 as long as we refer to it; + // closing it is the easy choice. + fd3.Close() + + os.Stdout.Write(bs) +} |