refactor: Tidy up signals, last syscall completion and type handlers

printer/printer.go

@@ -16,6 +16,7 @@ type Printer struct {
 	argProgress         int
 	extraNewLine        bool
 	multiline           bool
+	inSyscall           bool
 }
 
 func New(w io.Writer) *Printer {
@@ -82,8 +83,11 @@ func (p *Printer) PrintProcessExit(i int) {
 	if i != 0 {
 		colour = ColourRed
 	}
+	if p.inSyscall {
+		p.PrintDim(" = ?\n")
+	}
 	if p.multiline {
 		p.Print("\n")
 	}
-	p.PrintColour(colour, "\nProcess exited with status %d\n", i)
+	p.PrintColour(colour, "Process exited with status %d\n", i)
 }

printer/signal.go

@@ -5,16 +5,47 @@ import (
 	"syscall"
 )
 
+var signals = map[syscall.Signal]string{
+	syscall.SIGABRT:   "SIGABRT",
+	syscall.SIGALRM:   "SIGALRM",
+	syscall.SIGBUS:    "SIGBUS",
+	syscall.SIGCHLD:   "SIGCHLD",
+	syscall.SIGCONT:   "SIGCONT",
+	syscall.SIGFPE:    "SIGFPE",
+	syscall.SIGHUP:    "SIGHUP",
+	syscall.SIGILL:    "SIGILL",
+	syscall.SIGINT:    "SIGINT",
+	syscall.SIGIO:     "SIGIO",
+	syscall.SIGKILL:   "SIGKILL",
+	syscall.SIGPIPE:   "SIGPIPE",
+	syscall.SIGPROF:   "SIGPROF",
+	syscall.SIGPWR:    "SIGPWR",
+	syscall.SIGQUIT:   "SIGQUIT",
+	syscall.SIGSEGV:   "SIGSEGV",
+	syscall.SIGSTKFLT: "SIGSTKFLT",
+	syscall.SIGSTOP:   "SIGSTOP",
+	syscall.SIGSYS:    "SIGSYS",
+	syscall.SIGTERM:   "SIGTERM",
+	syscall.SIGTRAP:   "SIGTRAP",
+	syscall.SIGTSTP:   "SIGTSTP",
+	syscall.SIGTTIN:   "SIGTTIN",
+	syscall.SIGTTOU:   "SIGTTOU",
+	syscall.SIGURG:    "SIGURG",
+	syscall.SIGUSR1:   "SIGUSR1",
+	syscall.SIGUSR2:   "SIGUSR2",
+	syscall.SIGVTALRM: "SIGVTALRM",
+	syscall.SIGWINCH:  "SIGWINCH",
+	syscall.SIGXCPU:   "SIGXCPU",
+	syscall.SIGXFSZ:   "SIGXFSZ",
+}
+
 func (p *Printer) PrintSignal(signal syscall.Signal) {
 	p.PrintColour(ColourYellow, "--> SIGNAL: %s <--\n", signalToString(signal))
 }
 
 func signalToString(signal syscall.Signal) string {
-	switch signal {
-	// TODO: more signals
-	case syscall.SIGURG:
-		return "SIGURG"
-	default:
-		return fmt.Sprintf("signal %d", signal)
+	if str, ok := signals[signal]; ok {
+		return str
 	}
+	return fmt.Sprintf("%d", signal)
 }

printer/syscall.go

@@ -11,6 +11,7 @@ func (p *Printer) PrintSyscallEnter(syscall *tracer.Syscall) {
 		p.PrintColour(ColourDefault, syscall.Name())
 	}
 	p.printRemainingArgs(syscall, false)
+	p.inSyscall = true
 }
 
 func (p *Printer) PrintSyscallExit(syscall *tracer.Syscall) {
@@ -22,6 +23,7 @@ func (p *Printer) PrintSyscallExit(syscall *tracer.Syscall) {
 	if p.extraNewLine {
 		p.Print("\n")
 	}
+	p.inSyscall = false
 }
 
 func (p *Printer) printRemainingArgs(syscall *tracer.Syscall, exit bool) {

tracer/args.go

@@ -22,25 +22,6 @@ const (
 
 type ReturnMetadata ArgMetadata
 
-type ArgType int
-
-const (
-	ArgTypeUnknown ArgType = iota
-	ArgTypeData
-	ArgTypeInt
-	ArgTypeStat
-	ArgTypeLong
-	ArgTypeAddress
-	ArgTypeUnsignedInt
-	ArgTypeUnsignedLong
-	ArgTypePollFdArray
-	ArgTypeObject
-	ArgTypeErrorCode
-	ArgTypeSigAction
-	ArgTypeIovecArray
-	ArgTypeIntArray
-)
-
 type Arg struct {
 	name       string
 	t          ArgType

tracer/sys_amd64.go

@@ -566,6 +566,9 @@ var (
 		},
 		unix.SYS_OPENAT: {
 			Name: "openat",
+			ReturnValue: ReturnMetadata{
+				Type: ArgTypeInt,
+			},
 			Args: []ArgMetadata{
 				{
 					Name:      "dfd",
@@ -592,6 +595,9 @@ var (
 		},
 		unix.SYS_NEWFSTATAT: {
 			Name: "newfstatat",
+			ReturnValue: ReturnMetadata{
+				Type: ArgTypeErrorCode,
+			},
 			Args: []ArgMetadata{
 				{
 					Name:      "dfd",
@@ -616,6 +622,9 @@ var (
 		},
 		unix.SYS_EXIT: {
 			Name: "exit",
+			ReturnValue: ReturnMetadata{
+				Type: ArgTypeErrorCode,
+			},
 			Args: []ArgMetadata{
 				{
 					Name: "status",
@@ -625,6 +634,9 @@ var (
 		},
 		unix.SYS_EXIT_GROUP: {
 			Name: "exit_group",
+			ReturnValue: ReturnMetadata{
+				Type: ArgTypeErrorCode,
+			},
 			Args: []ArgMetadata{
 				{
 					Name: "status",

tracer/types.go

@@ -5,6 +5,25 @@ import (
 	"sync"
 )
 
+type ArgType int
+
+const (
+	ArgTypeUnknown ArgType = iota
+	ArgTypeData
+	ArgTypeInt
+	ArgTypeStat
+	ArgTypeLong
+	ArgTypeAddress
+	ArgTypeUnsignedInt
+	ArgTypeUnsignedLong
+	ArgTypePollFdArray
+	ArgTypeObject
+	ArgTypeErrorCode
+	ArgTypeSigAction
+	ArgTypeIovecArray
+	ArgTypeIntArray
+)
+
 type typeHandler func(arg *Arg, metadata ArgMetadata, raw uintptr, next uintptr, ret uintptr, pid int) error
 
 var typesRegistry = map[ArgType]typeHandler{}
@@ -25,5 +44,5 @@ func handleType(arg *Arg, metadata ArgMetadata, raw uintptr, next uintptr, ret u
 	if h, ok := typesRegistry[metadata.Type]; ok {
 		return h(arg, metadata, raw, next, ret, pid)
 	}
-	return fmt.Errorf("no handler registered for type %d", metadata.Type)
+	return nil
 }