// SetRegisters is a wrapper for ptrace(PTRACE_SETREGS)
func (p *Process) SetRegisters(regs *RegisterState) bool {
err := syscall.PtraceSetRegs(p.Pid, ®s.PtraceRegs)
if err != nil {
return false
}
return true
}
func (t *thread) ptraceSetRegs(regs *syscall.PtraceRegs) os.Error {
err := syscall.PtraceSetRegs(t.tid, regs)
return os.NewSyscallError("ptrace(SETREGS)", err)
}
func (t *Tracer) SetRegs(regs *syscall.PtraceRegs) error {
return syscall.PtraceSetRegs(t.Process.Pid, regs)
}
func run() {
// If the debugger itself is multi-threaded, ptrace calls must come from
// the same thread that originally attached to the remote thread.
runtime.LockOSThread()
f, err := os.Open(exeFilename)
if err != nil {
log.Printf(`%q not found. Did you run "go build ." in that directory?`, exeFilename)
log.Fatalf("Open: %v", err)
}
defer f.Close()
dwarfData, err := loadDwarfData(f)
if err != nil {
log.Fatalf("loadDwarfData: %v", err)
}
proc, err := os.StartProcess(exeFilename, []string{exeFilename}, &os.ProcAttr{
Files: []*os.File{
os.Stdin,
os.Stdout,
os.Stderr,
},
Sys: &syscall.SysProcAttr{
Ptrace: true,
Pdeathsig: syscall.SIGKILL,
},
})
if err != nil {
log.Fatalf("StartProcess: %v", err)
}
fmt.Printf("\tproc.Pid=%d\n", proc.Pid)
_, status, err := wait(proc.Pid)
if err != nil {
log.Fatalf("wait: %v", err)
}
if status != 0x00057f { // 0x05=SIGTRAP, 0x7f=stopped.
log.Fatalf("status: got %#x, want %#x", status, 0x57f)
}
err = syscall.PtraceSetOptions(proc.Pid, syscall.PTRACE_O_TRACECLONE|syscall.PTRACE_O_TRACEEXIT)
if err != nil {
log.Fatalf("PtraceSetOptions: %v", err)
}
addr, err := lookupSym(dwarfData, "fmt.Printf")
if err != nil {
log.Fatalf("lookupSym: %v", err)
}
fmt.Printf("\tfmt.Printf=%#x\n", addr)
var buf [1]byte
if err := peek(proc.Pid, addr, buf[:1]); err != nil {
log.Fatalf("peek: %v", err)
}
breakpoints := map[uint64]breakpoint{
addr: {pc: addr, origInstr: buf[0]},
}
buf[0] = breakpointInstr
if err := poke(proc.Pid, addr, buf[:1]); err != nil {
log.Fatalf("poke: %v", err)
}
err = syscall.PtraceCont(proc.Pid, 0)
if err != nil {
log.Fatalf("PtraceCont: %v", err)
}
for {
pid, status, err := wait(-1)
if err != nil {
log.Fatalf("wait: %v", err)
}
switch status {
case 0x00057f: // 0x05=SIGTRAP, 0x7f=stopped.
regs := syscall.PtraceRegs{}
if err := syscall.PtraceGetRegs(pid, ®s); err != nil {
log.Fatalf("PtraceGetRegs: %v", err)
}
regs.Rip -= breakpointInstrLen
if err := syscall.PtraceSetRegs(pid, ®s); err != nil {
log.Fatalf("PtraceSetRegs: %v", err)
}
bp, ok := breakpoints[regs.Rip]
if !ok {
log.Fatalf("no breakpoint for address %#x\n", regs.Rip)
}
buf[0] = bp.origInstr
if err := poke(pid, addr, buf[:1]); err != nil {
log.Fatalf("poke: %v", err)
}
fmt.Printf("\thit breakpoint at %#x, pid=%5d\n", regs.Rip, pid)
if err := syscall.PtraceSingleStep(pid); err != nil {
log.Fatalf("PtraceSingleStep: %v", err)
}
_, status, err := wait(pid)
if err != nil {
log.Fatalf("wait: %v", err)
}
if status != 0x00057f {
log.Fatalf("PtraceSingleStep: unexpected status %#x\n", status)
}
buf[0] = breakpointInstr
if err := poke(pid, addr, buf[:1]); err != nil {
log.Fatalf("poke: %v", err)
}
case 0x00137f: // 0x13=SIGSTOP, 0x7f=stopped.
// No-op.
case 0x03057f: // 0x05=SIGTRAP, 0x7f=stopped, 0x03=PTRACE_EVENT_CLONE.
msg, err := syscall.PtraceGetEventMsg(pid)
if err != nil {
log.Fatalf("PtraceGetEventMsg: %v", err)
}
fmt.Printf("\tclone: new pid=%d\n", msg)
default:
log.Fatalf("unexpected status %#x\n", status)
}
err = syscall.PtraceCont(pid, 0)
if err != nil {
log.Fatalf("PtraceCont: %v", err)
}
}
}
func (s *Server) ptraceSetRegs(pid int, regs *syscall.PtraceRegs) (err error) {
s.fc <- func() error {
return syscall.PtraceSetRegs(pid, regs)
}
return <-s.ec
}