service/debugger,terminal: API and user interface for follow exec mode

Updates #2551

Documentation/cli/README.md

@@ -91,6 +91,7 @@ Command | Description
 [list](#list) | Show source code.
 [source](#source) | Executes a file containing a list of delve commands
 [sources](#sources) | Print list of source files.
+[target](#target) | Manages child process debugging.
 [transcript](#transcript) | Appends command output to a file.
 [types](#types) | Print list of types
 
@@ -623,6 +624,22 @@ Step out of the current function.
 
 Aliases: so
 
+## target
+Manages child process debugging.
+
+	target follow-exec [-on [regex]] [-off]
+
+Enables or disables follow exec mode. When follow exec mode Delve will automatically attach to new child processes executed by the target process. An optional regular expression can be passed to 'target follow-exec', only child processes with a command line matching the regular expression will be followed.
+
+	target list
+
+List currently attached processes.
+
+	target switch [pid]
+
+Switches to the specified process.
+
+
 ## thread
 Switch to the specified thread.
 

Documentation/cli/starlark.md

@@ -37,6 +37,8 @@ dump_wait(Wait) | Equivalent to API call [DumpWait](https://godoc.org/github.com
 eval(Scope, Expr, Cfg) | Equivalent to API call [Eval](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.Eval)
 examine_memory(Address, Length) | Equivalent to API call [ExamineMemory](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.ExamineMemory)
 find_location(Scope, Loc, IncludeNonExecutableLines, SubstitutePathRules) | Equivalent to API call [FindLocation](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.FindLocation)
+follow_exec(Enable, Regex) | Equivalent to API call [FollowExec](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.FollowExec)
+follow_exec_enabled() | Equivalent to API call [FollowExecEnabled](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.FollowExecEnabled)
 function_return_locations(FnName) | Equivalent to API call [FunctionReturnLocations](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.FunctionReturnLocations)
 get_breakpoint(Id, Name) | Equivalent to API call [GetBreakpoint](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.GetBreakpoint)
 get_buffered_tracepoints() | Equivalent to API call [GetBufferedTracepoints](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.GetBufferedTracepoints)
@@ -54,6 +56,7 @@ package_vars(Filter, Cfg) | Equivalent to API call [ListPackageVars](https://god
 packages_build_info(IncludeFiles) | Equivalent to API call [ListPackagesBuildInfo](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.ListPackagesBuildInfo)
 registers(ThreadID, IncludeFp, Scope) | Equivalent to API call [ListRegisters](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.ListRegisters)
 sources(Filter) | Equivalent to API call [ListSources](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.ListSources)
+targets() | Equivalent to API call [ListTargets](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.ListTargets)
 threads() | Equivalent to API call [ListThreads](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.ListThreads)
 types(Filter) | Equivalent to API call [ListTypes](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.ListTypes)
 process_pid() | Equivalent to API call [ProcessPid](https://godoc.org/github.com/go-delve/delve/service/rpc2#RPCServer.ProcessPid)

pkg/proc/target_group.go

@@ -354,6 +354,11 @@ func (grp *TargetGroup) FollowExec(v bool, regex string) error {
 	return nil
 }
 
+// FollowExecEnabled returns true if follow exec is enabled
+func (grp *TargetGroup) FollowExecEnabled() bool {
+	return grp.followExecEnabled
+}
+
 // ValidTargets iterates through all valid targets in Group.
 type ValidTargets struct {
 	*Target

pkg/terminal/command.go

@@ -559,6 +559,20 @@ The core dump is always written in ELF, even on systems (windows, macOS) where t
 Output of Delve's command is appended to the specified output file. If '-t' is specified and the output file exists it is truncated. If '-x' is specified output to stdout is suppressed instead.
 
 Using the -off option disables the transcript.`},
+
+		{aliases: []string{"target"}, cmdFn: target, helpMsg: `Manages child process debugging.
+
+	target follow-exec [-on [regex]] [-off]
+
+Enables or disables follow exec mode. When follow exec mode Delve will automatically attach to new child processes executed by the target process. An optional regular expression can be passed to 'target follow-exec', only child processes with a command line matching the regular expression will be followed.
+
+	target list
+
+List currently attached processes.
+
+	target switch [pid]
+
+Switches to the specified process.`},
 	}
 
 	addrecorded := client == nil
@@ -1212,6 +1226,7 @@ func parseOptionalCount(arg string) (int64, error) {
 }
 
 func restartLive(t *Term, ctx callContext, args string) error {
+	t.oldPid = 0
 	resetArgs, newArgv, newRedirects, err := parseNewArgv(args)
 	if err != nil {
 		return err
@@ -2522,6 +2537,12 @@ func printcontext(t *Term, state *api.DebuggerState) {
 		return
 	}
 
+	if state.Pid != t.oldPid {
+		if t.oldPid != 0 {
+			fmt.Fprintf(t.stdout, "Switch target process from %d to %d\n", t.oldPid, state.Pid)
+		}
+		t.oldPid = state.Pid
+	}
 	for i := range state.Threads {
 		if (state.CurrentThread != nil) && (state.Threads[i].ID == state.CurrentThread.ID) {
 			continue
@@ -3177,6 +3198,71 @@ func transcript(t *Term, ctx callContext, args string) error {
 	return nil
 }
 
+func target(t *Term, ctx callContext, args string) error {
+	argv := config.Split2PartsBySpace(args)
+	switch argv[0] {
+	case "list":
+		tgts, err := t.client.ListTargets()
+		if err != nil {
+			return err
+		}
+		w := new(tabwriter.Writer)
+		w.Init(t.stdout, 4, 4, 2, ' ', 0)
+		for _, tgt := range tgts {
+			selected := ""
+			if tgt.Pid == t.oldPid {
+				selected = "*"
+			}
+			fmt.Fprintf(w, "%s\t%d\t%s\n", selected, tgt.Pid, tgt.CmdLine)
+		}
+		w.Flush()
+		return nil
+	case "follow-exec":
+		if len(argv) == 1 {
+			return errors.New("not enough arguments")
+		}
+		argv = config.Split2PartsBySpace(argv[1])
+		switch argv[0] {
+		case "-on":
+			var regex string
+			if len(argv) == 2 {
+				regex = argv[1]
+			}
+			t.client.FollowExec(true, regex)
+		case "-off":
+			if len(argv) > 1 {
+				return errors.New("too many arguments")
+			}
+			t.client.FollowExec(false, "")
+		default:
+			return fmt.Errorf("unknown argument %q to 'target follow-exec'", argv[0])
+		}
+		return nil
+	case "switch":
+		tgts, err := t.client.ListTargets()
+		if err != nil {
+			return err
+		}
+		pid, err := strconv.Atoi(argv[1])
+		if err != nil {
+			return err
+		}
+		found := false
+		for _, tgt := range tgts {
+			if tgt.Pid == pid {
+				found = true
+				t.client.SwitchThread(tgt.CurrentThread.ID)
+			}
+		}
+		if !found {
+			return fmt.Errorf("could not find target %d", pid)
+		}
+		return nil
+	default:
+		return fmt.Errorf("unknown command 'target %s'", argv[0])
+	}
+}
+
 func formatBreakpointName(bp *api.Breakpoint, upcase bool) string {
 	thing := "breakpoint"
 	if bp.Tracepoint {
@@ -3226,5 +3312,5 @@ func (t *Term) formatBreakpointLocation(bp *api.Breakpoint) string {
 func shouldAskToSuspendBreakpoint(t *Term) bool {
 	fns, _ := t.client.ListFunctions(`^plugin\.Open$`)
 	_, err := t.client.GetState()
-	return len(fns) > 0 || isErrProcessExited(err)
+	return len(fns) > 0 || isErrProcessExited(err) || t.client.FollowExecEnabled()
 }

pkg/terminal/starbind/starlark_mapping.go

@@ -730,6 +730,56 @@ func (env *Env) starlarkPredeclare() starlark.StringDict {
 		}
 		return env.interfaceToStarlarkValue(rpcRet), nil
 	})
+	r["follow_exec"] = starlark.NewBuiltin("follow_exec", func(thread *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
+		if err := isCancelled(thread); err != nil {
+			return starlark.None, decorateError(thread, err)
+		}
+		var rpcArgs rpc2.FollowExecIn
+		var rpcRet rpc2.FollowExecOut
+		if len(args) > 0 && args[0] != starlark.None {
+			err := unmarshalStarlarkValue(args[0], &rpcArgs.Enable, "Enable")
+			if err != nil {
+				return starlark.None, decorateError(thread, err)
+			}
+		}
+		if len(args) > 1 && args[1] != starlark.None {
+			err := unmarshalStarlarkValue(args[1], &rpcArgs.Regex, "Regex")
+			if err != nil {
+				return starlark.None, decorateError(thread, err)
+			}
+		}
+		for _, kv := range kwargs {
+			var err error
+			switch kv[0].(starlark.String) {
+			case "Enable":
+				err = unmarshalStarlarkValue(kv[1], &rpcArgs.Enable, "Enable")
+			case "Regex":
+				err = unmarshalStarlarkValue(kv[1], &rpcArgs.Regex, "Regex")
+			default:
+				err = fmt.Errorf("unknown argument %q", kv[0])
+			}
+			if err != nil {
+				return starlark.None, decorateError(thread, err)
+			}
+		}
+		err := env.ctx.Client().CallAPI("FollowExec", &rpcArgs, &rpcRet)
+		if err != nil {
+			return starlark.None, err
+		}
+		return env.interfaceToStarlarkValue(rpcRet), nil
+	})
+	r["follow_exec_enabled"] = starlark.NewBuiltin("follow_exec_enabled", func(thread *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
+		if err := isCancelled(thread); err != nil {
+			return starlark.None, decorateError(thread, err)
+		}
+		var rpcArgs rpc2.FollowExecEnabledIn
+		var rpcRet rpc2.FollowExecEnabledOut
+		err := env.ctx.Client().CallAPI("FollowExecEnabled", &rpcArgs, &rpcRet)
+		if err != nil {
+			return starlark.None, err
+		}
+		return env.interfaceToStarlarkValue(rpcRet), nil
+	})
 	r["function_return_locations"] = starlark.NewBuiltin("function_return_locations", func(thread *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
 		if err := isCancelled(thread); err != nil {
 			return starlark.None, decorateError(thread, err)
@@ -1235,6 +1285,18 @@ func (env *Env) starlarkPredeclare() starlark.StringDict {
 		}
 		return env.interfaceToStarlarkValue(rpcRet), nil
 	})
+	r["targets"] = starlark.NewBuiltin("targets", func(thread *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
+		if err := isCancelled(thread); err != nil {
+			return starlark.None, decorateError(thread, err)
+		}
+		var rpcArgs rpc2.ListTargetsIn
+		var rpcRet rpc2.ListTargetsOut
+		err := env.ctx.Client().CallAPI("ListTargets", &rpcArgs, &rpcRet)
+		if err != nil {
+			return starlark.None, err
+		}
+		return env.interfaceToStarlarkValue(rpcRet), nil
+	})
 	r["threads"] = starlark.NewBuiltin("threads", func(thread *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
 		if err := isCancelled(thread); err != nil {
 			return starlark.None, decorateError(thread, err)

pkg/terminal/terminal.go

@@ -58,6 +58,7 @@ type Term struct {
 	stdout   *transcriptWriter
 	InitFile string
 	displays []displayEntry
+	oldPid   int
 
 	historyFile *os.File
 
@@ -115,6 +116,9 @@ func New(client service.Client, conf *config.Config) *Term {
 	if client != nil {
 		lcfg := t.loadConfig()
 		client.SetReturnValuesLoadConfig(&lcfg)
+		if state, err := client.GetState(); err == nil {
+			t.oldPid = state.Pid
+		}
 	}
 
 	t.starlarkEnv = starbind.New(starlarkContext{t}, t.stdout)

service/api/conversions.go

@@ -429,10 +429,12 @@ func ConvertRegisters(in *op.DwarfRegisters, dwarfRegisterToString func(int, *op
 	return
 }
 
+// ConvertImage convers proc.Image to api.Image.
 func ConvertImage(image *proc.Image) Image {
 	return Image{Path: image.Path, Address: image.StaticBase}
 }
 
+// ConvertDumpState converts proc.DumpState to api.DumpState.
 func ConvertDumpState(dumpState *proc.DumpState) *DumpState {
 	dumpState.Mutex.Lock()
 	defer dumpState.Mutex.Unlock()
@@ -449,3 +451,12 @@ func ConvertDumpState(dumpState *proc.DumpState) *DumpState {
 	}
 	return r
 }
+
+// ConvertTarget converts a proc.Target into a api.Target.
+func ConvertTarget(tgt *proc.Target, convertThreadBreakpoint func(proc.Thread) *Breakpoint) *Target {
+	//TODO(aarzilli): copy command line here
+	return &Target{
+		Pid:           tgt.Pid(),
+		CurrentThread: ConvertThread(tgt.CurrentThread(), convertThreadBreakpoint(tgt.CurrentThread())),
+	}
+}

service/api/types.go

@@ -655,3 +655,10 @@ type GoroutineGroupingOptions struct {
 	MaxGroupMembers int
 	MaxGroups       int
 }
+
+// Target represents a debugging target.
+type Target struct {
+	Pid           int
+	CmdLine       string
+	CurrentThread *Thread
+}

service/client.go

@@ -185,6 +185,14 @@ type Client interface {
 	// CoreDumpCancel cancels a core dump in progress
 	CoreDumpCancel() error
 
+	// ListTargets returns the list of connected targets
+	ListTargets() ([]api.Target, error)
+	// FollowExec enables or disables the follow exec mode. In follow exec mode
+	// Delve will automatically debug child processes launched by the target
+	// process
+	FollowExec(bool, string) error
+	FollowExecEnabled() bool
+
 	// Disconnect closes the connection to the server without sending a Detach request first.
 	// If cont is true a continue command will be sent instead.
 	Disconnect(cont bool) error

service/debugger/debugger.go

@@ -1264,6 +1264,13 @@ func (d *Debugger) Command(command *api.DebuggerCommand, resumeNotify chan struc
 		err = d.target.StepOut()
 	case api.SwitchThread:
 		d.log.Debugf("switching to thread %d", command.ThreadID)
+		t := proc.ValidTargets{Group: d.target}
+		for t.Next() {
+			if _, ok := t.FindThread(command.ThreadID); ok {
+				d.target.Selected = t.Target
+				break
+			}
+		}
 		err = d.target.Selected.SwitchThread(command.ThreadID)
 		withBreakpointInfo = false
 	case api.SwitchGoroutine:
@@ -2247,6 +2254,20 @@ func (d *Debugger) GetBufferedTracepoints() []api.TracepointResult {
 	return results
 }
 
+// FollowExec enabled or disables follow exec mode.
+func (d *Debugger) FollowExec(enabled bool, regex string) error {
+	d.targetMutex.Lock()
+	defer d.targetMutex.Unlock()
+	return d.target.FollowExec(enabled, regex)
+}
+
+// FollowExecEnabled returns true if follow exec mode is enabled.
+func (d *Debugger) FollowExecEnabled() bool {
+	d.targetMutex.Lock()
+	defer d.targetMutex.Unlock()
+	return d.target.FollowExecEnabled()
+}
+
 func go11DecodeErrorCheck(err error) error {
 	if _, isdecodeerr := err.(dwarf.DecodeError); !isdecodeerr {
 		return err

service/rpc2/client.go

@@ -530,6 +530,30 @@ func (c *RPCClient) CoreDumpCancel() error {
 	return c.call("DumpCancel", DumpCancelIn{}, out)
 }
 
+// ListTargets returns the current list of debug targets.
+func (c *RPCClient) ListTargets() ([]api.Target, error) {
+	out := &ListTargetsOut{}
+	err := c.call("ListTargets", ListTargetsIn{}, out)
+	return out.Targets, err
+}
+
+// FollowExec enabled or disabled follow exec mode. When follow exec is
+// enabled Delve will automatically attach to new subprocesses with a
+// command line matched by regex, if regex is nil all new subprocesses are
+// automatically debugged.
+func (c *RPCClient) FollowExec(v bool, regex string) error {
+	out := &FollowExecOut{}
+	err := c.call("FollowExec", FollowExecIn{Enable: v, Regex: regex}, out)
+	return err
+}
+
+// FollowExecEnabled returns true if follow exex mode is enabled.
+func (c *RPCClient) FollowExecEnabled() bool {
+	out := &FollowExecEnabledOut{}
+	_ = c.call("FollowExecEnabled", FollowExecEnabledIn{}, out)
+	return out.Enabled
+}
+
 func (c *RPCClient) call(method string, args, reply interface{}) error {
 	return c.client.Call("RPCServer."+method, args, reply)
 }