os: don't permit Process.Signal after a successful Wait
R=dsymonds, rsc
CC=golang-dev
https://golang.org/cl/4689043
diff --git a/src/pkg/os/exec.go b/src/pkg/os/exec.go
index e2234f1..40e6c17 100644
--- a/src/pkg/os/exec.go
+++ b/src/pkg/os/exec.go
@@ -13,10 +13,11 @@
type Process struct {
Pid int
handle int
+ done bool // process has been successfuly waited on
}
func newProcess(pid, handle int) *Process {
- p := &Process{pid, handle}
+ p := &Process{Pid: pid, handle: handle}
runtime.SetFinalizer(p, (*Process).Release)
return p
}
diff --git a/src/pkg/os/exec_unix.go b/src/pkg/os/exec_unix.go
index cf5ea9b..8a4b2e1 100644
--- a/src/pkg/os/exec_unix.go
+++ b/src/pkg/os/exec_unix.go
@@ -38,6 +38,9 @@
if e != 0 {
return nil, NewSyscallError("wait", e)
}
+ if options&WSTOPPED == 0 {
+ p.done = true
+ }
w = new(Waitmsg)
w.Pid = pid1
w.WaitStatus = status
@@ -47,6 +50,9 @@
// Signal sends a signal to the Process.
func (p *Process) Signal(sig Signal) Error {
+ if p.done {
+ return NewError("os: process already finished")
+ }
if e := syscall.Kill(p.Pid, int(sig.(UnixSignal))); e != 0 {
return Errno(e)
}
diff --git a/src/pkg/os/exec_windows.go b/src/pkg/os/exec_windows.go
index 5b432d3..65e94ac4 100644
--- a/src/pkg/os/exec_windows.go
+++ b/src/pkg/os/exec_windows.go
@@ -24,11 +24,15 @@
if e != 0 {
return nil, NewSyscallError("GetExitCodeProcess", e)
}
+ p.done = true
return &Waitmsg{p.Pid, syscall.WaitStatus{s, ec}, new(syscall.Rusage)}, nil
}
// Signal sends a signal to the Process.
func (p *Process) Signal(sig Signal) Error {
+ if p.done {
+ return NewError("os: process already finished")
+ }
switch sig.(UnixSignal) {
case SIGKILL:
e := syscall.TerminateProcess(syscall.Handle(p.handle), 1)
diff --git a/src/pkg/os/os_test.go b/src/pkg/os/os_test.go
index c22b536..dadae03 100644
--- a/src/pkg/os/os_test.go
+++ b/src/pkg/os/os_test.go
@@ -895,7 +895,14 @@
var b bytes.Buffer
io.Copy(&b, r)
- p.Wait(0)
+ _, err = p.Wait(0)
+ if err != nil {
+ t.Fatalf("run hostname Wait: %v", err)
+ }
+ err = p.Kill()
+ if err == nil {
+ t.Errorf("expected an error from Kill running 'hostname'")
+ }
output := b.String()
if n := len(output); n > 0 && output[n-1] == '\n' {
output = output[0 : n-1]
