[process] Fix #729 check process existence in NewProcess()

process/process.go

@@ -16,6 +16,7 @@ import (
 var (
 	invoke          common.Invoker = common.Invoke{}
 	ErrorNoChildren                = errors.New("process does not have children")
+	ErrorProcessNotRunning         = errors.New("process does not exist")
 )
 
 type Process struct {
@@ -136,6 +137,23 @@ func (p NumCtxSwitchesStat) String() string {
 	return string(s)
 }
 
+// NewProcess creates a new Process instance, it only stores the pid and
+// checks that the process exists. Other method on Process can be used
+// to get more information about the process. An error will be returned
+// if the process does not exist.
+func NewProcess(pid int32) (*Process, error) {
+	p := &Process{Pid: pid}
+
+	exists, err := PidExists(pid)
+	if err != nil {
+		return p, err
+	}
+	if !exists {
+		return p, ErrorProcessNotRunning
+	}
+	return p, nil
+}
+
 func PidExists(pid int32) (bool, error) {
 	return PidExistsWithContext(context.Background(), pid)
 }

process/process_darwin.go

@@ -634,12 +634,6 @@ func (p *Process) getKProcWithContext(ctx context.Context) (*KinfoProc, error) {
 	return &k, nil
 }
 
-func NewProcess(pid int32) (*Process, error) {
-	p := &Process{Pid: pid}
-
-	return p, nil
-}
-
 // call ps command.
 // Return value deletes Header line(you must not input wrong arg).
 // And splited by Space. Caller have responsibility to manage.

process/process_fallback.go

@@ -44,10 +44,6 @@ func ProcessesWithContext(ctx context.Context) ([]*Process, error) {
 	return nil, common.ErrNotImplementedError
 }
 
-func NewProcess(pid int32) (*Process, error) {
-	return nil, common.ErrNotImplementedError
-}
-
 func PidExistsWithContext(ctx context.Context, pid int32) (bool, error) {
 	pids, err := PidsWithContext(ctx)
 	if err != nil {

process/process_freebsd.go

@@ -510,9 +510,3 @@ func (p *Process) getKProcWithContext(ctx context.Context) (*KinfoProc, error) {
 	}
 	return &k, nil
 }
-
-func NewProcess(pid int32) (*Process, error) {
-	p := &Process{Pid: pid}
-
-	return p, nil
-}

process/process_linux.go

@@ -64,15 +64,6 @@ func (m MemoryMapsStat) String() string {
 	return string(s)
 }
 
-// NewProcess creates a new Process instance, it only stores the pid and
-// checks that the process exists. Other method on Process can be used
-// to get more information about the process. An error will be returned
-// if the process does not exist.
-func NewProcess(pid int32) (*Process, error) {
-	_, err := os.Stat(common.HostProc(strconv.Itoa(int(pid))))
-	return &Process{Pid: pid}, err
-}
-
 // Ppid returns Parent Process ID of the process.
 func (p *Process) Ppid() (int32, error) {
 	return p.PpidWithContext(context.Background())

process/process_openbsd.go

@@ -496,12 +496,6 @@ func (p *Process) getKProcWithContext(ctx context.Context) (*KinfoProc, error) {
 	return &k, nil
 }
 
-func NewProcess(pid int32) (*Process, error) {
-	p := &Process{Pid: pid}
-
-	return p, nil
-}
-
 func CallKernProcSyscall(op int32, arg int32) ([]byte, uint64, error) {
 	return CallKernProcSyscallWithContext(context.Background(), op, arg)
 }

process/process_windows.go

@@ -680,12 +680,6 @@ func (p *Process) MemoryMapsWithContext(ctx context.Context, grouped bool) (*[]M
 	return &ret, common.ErrNotImplementedError
 }
 
-func NewProcess(pid int32) (*Process, error) {
-	p := &Process{Pid: pid}
-
-	return p, nil
-}
-
 func (p *Process) SendSignal(sig windows.Signal) error {
 	return p.SendSignalWithContext(context.Background(), sig)
 }