unix: add ptrace support for FreeBSD

Change-Id: Iaf95e3e7bd3d33ad7e214c45ed87b9e967b16631
GitHub-Last-Rev: e0308dc7ad566b70922a499e81610a746afe84ac
GitHub-Pull-Request: golang/sys#34
Reviewed-on: https://go-review.googlesource.com/c/sys/+/179099
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

unix/syscall_freebsd.go

@@ -521,6 +521,70 @@ func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err e
 	return sendfile(outfd, infd, offset, count)
 }
 
+//sys	ptrace(request int, pid int, addr uintptr, data int) (err error)
+
+func PtraceAttach(pid int) (err error) {
+	return ptrace(PTRACE_ATTACH, pid, 0, 0)
+}
+
+func PtraceCont(pid int, signal int) (err error) {
+	return ptrace(PTRACE_CONT, pid, 1, signal)
+}
+
+func PtraceDetach(pid int) (err error) {
+	return ptrace(PTRACE_DETACH, pid, 1, 0)
+}
+
+func PtraceGetFpRegs(pid int, fpregsout *FpReg) (err error) {
+	return ptrace(PTRACE_GETFPREGS, pid, uintptr(unsafe.Pointer(fpregsout)), 0)
+}
+
+func PtraceGetFsBase(pid int, fsbase *int64) (err error) {
+	return ptrace(PTRACE_GETFSBASE, pid, uintptr(unsafe.Pointer(fsbase)), 0)
+}
+
+func PtraceGetRegs(pid int, regsout *Reg) (err error) {
+	return ptrace(PTRACE_GETREGS, pid, uintptr(unsafe.Pointer(regsout)), 0)
+}
+
+func PtraceIO(req int, pid int, addr uintptr, out []byte, countin int) (count int, err error) {
+	ioDesc := PtraceIoDesc{Op: int32(req), Offs: (*byte)(unsafe.Pointer(addr)), Addr: (*byte)(unsafe.Pointer(&out[0])), Len: uint(countin)}
+	err = ptrace(PTRACE_IO, pid, uintptr(unsafe.Pointer(&ioDesc)), 0)
+	return int(ioDesc.Len), err
+}
+
+func PtraceLwpEvents(pid int, enable int) (err error) {
+	return ptrace(PTRACE_LWPEVENTS, pid, 0, enable)
+}
+
+func PtraceLwpInfo(pid int, info uintptr) (err error) {
+	return ptrace(PTRACE_LWPINFO, pid, info, int(unsafe.Sizeof(PtraceLwpInfoStruct{})))
+}
+
+func PtracePeekData(pid int, addr uintptr, out []byte) (count int, err error) {
+	return PtraceIO(PIOD_READ_D, pid, addr, out, SizeofLong)
+}
+
+func PtracePeekText(pid int, addr uintptr, out []byte) (count int, err error) {
+	return PtraceIO(PIOD_READ_I, pid, addr, out, SizeofLong)
+}
+
+func PtracePokeData(pid int, addr uintptr, data []byte) (count int, err error) {
+	return PtraceIO(PIOD_WRITE_D, pid, addr, data, SizeofLong)
+}
+
+func PtracePokeText(pid int, addr uintptr, data []byte) (count int, err error) {
+	return PtraceIO(PIOD_WRITE_I, pid, addr, data, SizeofLong)
+}
+
+func PtraceSetRegs(pid int, regs *Reg) (err error) {
+	return ptrace(PTRACE_SETREGS, pid, uintptr(unsafe.Pointer(regs)), 0)
+}
+
+func PtraceSingleStep(pid int) (err error) {
+	return ptrace(PTRACE_SINGLESTEP, pid, 1, 0)
+}
+
 /*
  * Exposed directly
  */