Implement linux amd64 step

fixtures/testprog.go

@@ -0,0 +1,11 @@
+package main
+
+import (
+	"fmt"
+	"time"
+)
+
+func main() {
+	time.Sleep(time.Second)
+	fmt.Println("Hello, World!")
+}

proctl/proctl_linux_amd64.go

@@ -0,0 +1,61 @@
+package proctl
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+)
+
+type DebuggedProcess struct {
+	Pid     int
+	Regs    *syscall.PtraceRegs
+	Process *os.Process
+}
+
+func NewDebugProcess(pid int) (*DebuggedProcess, error) {
+	err := syscall.PtraceAttach(pid)
+	if err != nil {
+		return nil, err
+	}
+
+	proc, err := os.FindProcess(pid)
+	if err != nil {
+		return nil, err
+	}
+
+	debuggedProc := DebuggedProcess{
+		Pid:     pid,
+		Regs:    &syscall.PtraceRegs{},
+		Process: proc,
+	}
+
+	_, err = proc.Wait()
+	if err != nil {
+		return nil, err
+	}
+
+	return &debuggedProc, nil
+}
+
+func (dbp *DebuggedProcess) Registers() (*syscall.PtraceRegs, error) {
+	err := syscall.PtraceGetRegs(dbp.Pid, dbp.Regs)
+	if err != nil {
+		return nil, fmt.Errorf("Registers():", err)
+	}
+
+	return dbp.Regs, nil
+}
+
+func (dbp *DebuggedProcess) Step() error {
+	err := syscall.PtraceSingleStep(dbp.Pid)
+	if err != nil {
+		return err
+	}
+
+	_, err = dbp.Process.Wait()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

proctl/proctl_test.go

@@ -0,0 +1,50 @@
+package proctl
+
+import (
+	"os/exec"
+	"testing"
+)
+
+func StartTestProcess() (int, error) {
+	cmd := exec.Command("../fixtures/testprog")
+
+	err := cmd.Start()
+	if err != nil {
+		return 0, err
+	}
+
+	return cmd.Process.Pid, nil
+}
+
+func TestStep(t *testing.T) {
+	pid, err := StartTestProcess()
+	if err != nil {
+		t.Fatal("Starting test process:", err)
+	}
+
+	p, err := NewDebugProcess(pid)
+	if err != nil {
+		t.Fatal("NewDebugProcess():", err)
+	}
+
+	regs, err := p.Registers()
+	if err != nil {
+		t.Fatal("Registers():", err)
+	}
+
+	rip := regs.PC()
+
+	err = p.Step()
+	if err != nil {
+		t.Fatal("Step():", err)
+	}
+
+	regs, err = p.Registers()
+	if err != nil {
+		t.Fatal("Registers():", err)
+	}
+
+	if rip >= regs.PC() {
+		t.Errorf("Expected %#v to be greater than %#v", regs.PC(), rip)
+	}
+}