Add command to restart process

Fixes #95

Makefile

@@ -2,10 +2,6 @@
 UNAME = $(shell uname)
 PREFIX=github.com/derekparker/delve
 
-ifndef $(RUN)
-	RUN = ".*"
-endif
-
 build:
 	go build github.com/derekparker/delve/cmd/dlv
 ifeq "$(UNAME)" "Darwin"

service/client.go

@@ -7,9 +7,15 @@ import (
 // Client represents a debugger service client. All client methods are
 // synchronous.
 type Client interface {
+	// Returns the pid of the process we are debugging.
+	ProcessPid() int
+
 	// Detach detaches the debugger, optionally killing the process.
 	Detach(killProcess bool) error
 
+	// Restarts program.
+	Restart() error
+
 	// GetState returns the current debugger state.
 	GetState() (*api.DebuggerState, error)
 

service/debugger/debugger.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/derekparker/delve/proc"
 	"github.com/derekparker/delve/service/api"
+	sys "golang.org/x/sys/unix"
 )
 
 // Debugger service.
@@ -61,10 +62,35 @@ func New(config *Config) (*Debugger, error) {
 	return d, nil
 }
 
+func (d *Debugger) ProcessPid() int {
+	return d.process.Pid
+}
+
 func (d *Debugger) Detach(kill bool) error {
 	return d.process.Detach(kill)
 }
 
+func (d *Debugger) Restart() error {
+	if !d.process.Exited() {
+		if d.process.Running() {
+			d.process.Halt()
+		}
+		// Ensure the process is in a PTRACE_STOP.
+		if err := sys.Kill(d.ProcessPid(), sys.SIGSTOP); err != nil {
+			return err
+		}
+		if err := d.Detach(true); err != nil {
+			return err
+		}
+	}
+	p, err := proc.Launch(d.config.ProcessArgs)
+	if err != nil {
+		return fmt.Errorf("could not launch process: %s", err)
+	}
+	d.process = p
+	return nil
+}
+
 func (d *Debugger) State() (*api.DebuggerState, error) {
 	var (
 		state  *api.DebuggerState

service/rpc/client.go

@@ -12,8 +12,9 @@ import (
 
 // Client is a RPC service.Client.
 type RPCClient struct {
-	addr   string
+	addr       string
-	client *rpc.Client
+	processPid int
+	client     *rpc.Client
 }
 
 // Ensure the implementation satisfies the interface.
@@ -31,10 +32,20 @@ func NewClient(addr string) *RPCClient {
 	}
 }
 
+func (c *RPCClient) ProcessPid() int {
+	var pid int
+	c.call("ProcessPid", nil, &pid)
+	return pid
+}
+
 func (c *RPCClient) Detach(kill bool) error {
 	return c.call("Detach", kill, nil)
 }
 
+func (c *RPCClient) Restart() error {
+	return c.call("Restart", nil, nil)
+}
+
 func (c *RPCClient) GetState() (*api.DebuggerState, error) {
 	state := new(api.DebuggerState)
 	err := c.call("State", nil, state)

service/rpc/server.go

@@ -67,10 +67,22 @@ func (s *RPCServer) Run() error {
 	return nil
 }
 
+func (s *RPCServer) ProcessPid(arg1 interface{}, pid *int) error {
+	*pid = s.debugger.ProcessPid()
+	return nil
+}
+
 func (s *RPCServer) Detach(kill bool, ret *int) error {
 	return s.debugger.Detach(kill)
 }
 
+func (s *RPCServer) Restart(arg1 interface{}, arg2 *int) error {
+	if s.config.AttachPid != 0 {
+		return errors.New("cannot restart process Delve did not create")
+	}
+	return s.debugger.Restart()
+}
+
 func (s *RPCServer) State(arg interface{}, state *api.DebuggerState) error {
 	st, err := s.debugger.State()
 	if err != nil {

service/test/integration_test.go

@@ -60,6 +60,69 @@ func TestRunWithInvalidPath(t *testing.T) {
 	}
 }
 
+func TestRestart_afterExit(t *testing.T) {
+	withTestClient("continuetestprog", t, func(c service.Client) {
+		origPid := c.ProcessPid()
+		state := <-c.Continue()
+		if !state.Exited {
+			t.Fatal("expected initial process to have exited")
+		}
+		if err := c.Restart(); err != nil {
+			t.Fatal(err)
+		}
+		if c.ProcessPid() == origPid {
+			t.Fatal("did not spawn new process, has same PID")
+		}
+		state = <-c.Continue()
+		if !state.Exited {
+			t.Fatal("expected restarted process to have exited")
+		}
+	})
+}
+
+func TestRestart_duringStop(t *testing.T) {
+	withTestClient("continuetestprog", t, func(c service.Client) {
+		origPid := c.ProcessPid()
+		_, err := c.CreateBreakpoint(&api.Breakpoint{FunctionName: "main.main"})
+		if err != nil {
+			t.Fatal(err)
+		}
+		state := <-c.Continue()
+		if state.Breakpoint == nil {
+			t.Fatal("did not hit breakpoint")
+		}
+		if err := c.Restart(); err != nil {
+			t.Fatal(err)
+		}
+		if c.ProcessPid() == origPid {
+			t.Fatal("did not spawn new process, has same PID")
+		}
+		bps, err := c.ListBreakpoints()
+		if err != nil {
+			t.Fatal(err)
+		}
+		if len(bps) != 0 {
+			t.Fatal("breakpoint tabe not cleared")
+		}
+		state = <-c.Continue()
+		if !state.Exited {
+			t.Fatal("expected process to have exited")
+		}
+	})
+}
+
+func TestRestart_attachPid(t *testing.T) {
+	// Assert it does not work and returns error.
+	// We cannot restart a process we did not spawn.
+	server := rpc.NewServer(&service.Config{
+		Listener:  nil,
+		AttachPid: 999,
+	}, false)
+	if err := server.Restart(nil, nil); err == nil {
+		t.Fatal("expected error on restart after attaching to pid but got none")
+	}
+}
+
 func TestClientServer_exit(t *testing.T) {
 	withTestClient("continuetestprog", t, func(c service.Client) {
 		state, err := c.GetState()

terminal/command.go

@@ -48,6 +48,7 @@ func DebugCommands(client service.Client) *Commands {
 		{aliases: []string{"help"}, cmdFn: c.help, helpMsg: "Prints the help message."},
 		{aliases: []string{"break", "b"}, cmdFn: breakpoint, helpMsg: "break <address> [-stack <n>|-goroutine|<variable name>]*\nSet break point at the entry point of a function, or at a specific file/line.\nWhen the breakpoint is reached the value of the specified variables will be printed, if -stack is specified the stack trace of the current goroutine will be printed, if -goroutine is specified informations about the current goroutine will be printed. Example: break foo.go:13"},
 		{aliases: []string{"trace", "t"}, cmdFn: tracepoint, helpMsg: "Set tracepoint, takes the same arguments as break"},
+		{aliases: []string{"restart", "r"}, cmdFn: restart, helpMsg: "Restart process."},
 		{aliases: []string{"continue", "c"}, cmdFn: cont, helpMsg: "Run until breakpoint or program termination."},
 		{aliases: []string{"step", "si"}, cmdFn: step, helpMsg: "Single step through program."},
 		{aliases: []string{"next", "n"}, cmdFn: next, helpMsg: "Step over to next source line."},
@@ -200,6 +201,14 @@ func formatGoroutine(g *api.Goroutine) string {
 	return fmt.Sprintf("%d - %s:%d %s (%#v)\n", g.ID, g.File, g.Line, fname, g.PC)
 }
 
+func restart(client service.Client, args ...string) error {
+	if err := client.Restart(); err != nil {
+		return err
+	}
+	fmt.Println("Process restarted with PID", client.ProcessPid())
+	return nil
+}
+
 func cont(client service.Client, args ...string) error {
 	stateChan := client.Continue()
 	for state := range stateChan {

terminal/terminal.go

@@ -76,7 +76,7 @@ func (t *Term) Run() (error, int) {
 		cmdstr, err := t.promptForInput()
 		if err != nil {
 			if err == io.EOF {
-				err, status = handleExit(t.client, t)
+				return handleExit(t.client, t)
 			}
 			err, status = fmt.Errorf("Prompt for input failed.\n"), 1
 			break