Remove parseProcessStatus and only report stop

Currently there is no need for the other items in the ProcessStatus
struct, we really only care if the process is not running, so we can
avoid sending signals to it.

proctl/proctl.go

@@ -39,21 +39,6 @@ func (mse ManualStopError) Error() string {
 	return "Manual stop requested"
 }
 
-// ProcessStatus is the result of parsing the data from
-// the /proc/<pid>/stats psuedo file.
-type ProcessStatus struct {
-	pid   int
-	comm  string
-	state rune
-	ppid  int
-}
-
-const (
-	STATUS_SLEEPING   = 'S'
-	STATUS_RUNNING    = 'R'
-	STATUS_TRACE_STOP = 't'
-)
-
 var (
 	breakpointIDCounter = 0
 )
@@ -215,8 +200,7 @@ func (dbp *DebuggedProcess) FindLocation(str string) (uint64, error) {
 func (dbp *DebuggedProcess) RequestManualStop() {
 	dbp.halt = true
 	for _, th := range dbp.Threads {
-		ps, _ := parseProcessStatus(th.Id)
-		if ps.state == STATUS_TRACE_STOP {
+		if stopped(th.Id) {
 			continue
 		}
 		syscall.Tgkill(dbp.Pid, th.Id, syscall.SIGSTOP)
@@ -493,21 +477,14 @@ func stopTheWorld(dbp *DebuggedProcess) error {
 	// are inactive. We send SIGSTOP and ensure all
 	// threads are in in signal-delivery-stop mode.
 	for _, th := range dbp.Threads {
-		ps, err := parseProcessStatus(th.Id)
-		if err != nil {
-			return err
-		}
-
-		if ps.state == STATUS_TRACE_STOP {
+		if stopped(th.Id) {
 			continue
 		}
-
-		err = syscall.Tgkill(dbp.Pid, th.Id, syscall.SIGSTOP)
+		err := syscall.Tgkill(dbp.Pid, th.Id, syscall.SIGSTOP)
 		if err != nil {
 			return err
 		}
-
-		pid, _, err := wait(th.Id, 0)
+		pid, _, err := wait(th.Id, syscall.WNOHANG)
 		if err != nil {
 			return fmt.Errorf("wait err %s %d", err, pid)
 		}

proctl/proctl_linux_amd64.go

@@ -11,6 +11,12 @@ import (
 	"github.com/derekparker/delve/dwarf/frame"
 )
 
+const (
+	STATUS_SLEEPING   = 'S'
+	STATUS_RUNNING    = 'R'
+	STATUS_TRACE_STOP = 't'
+)
+
 func (dbp *DebuggedProcess) addThread(tid int) (*ThreadContext, error) {
 	err := syscall.PtraceSetOptions(tid, syscall.PTRACE_O_TRACECLONE)
 	if err == syscall.ESRCH {
@@ -33,18 +39,23 @@ func (dbp *DebuggedProcess) addThread(tid int) (*ThreadContext, error) {
 	return dbp.Threads[tid], nil
 }
 
-func parseProcessStatus(pid int) (*ProcessStatus, error) {
-	var ps ProcessStatus
-
+func stopped(pid int) bool {
 	f, err := os.Open(fmt.Sprintf("/proc/%d/stat", pid))
 	if err != nil {
-		return nil, err
+		return false
 	}
 	defer f.Close()
 
-	fmt.Fscanf(f, "%d %s %c %d", &ps.pid, &ps.comm, &ps.state, &ps.ppid)
-
-	return &ps, nil
+	var (
+		p     int
+		comm  string
+		state rune
+	)
+	fmt.Fscanf(f, "%d %s %c", &p, &comm, &state)
+	if state == STATUS_TRACE_STOP {
+		return true
+	}
+	return false
 }
 
 // Finds the executable from /proc/<pid>/exe and then