unix: implement Ptrace{Set,Get}Regs using PTRACE_{GET,SET}REGSET for Linux

The same change was already done in CL 501756.

Fixes #60679.

Change-Id: I5d1f4ad89cabb0ac120b3d72876944fb3283ec6f
Reviewed-on: https://go-review.googlesource.com/c/sys/+/501795
Auto-Submit: Ian Lance Taylor <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
Reviewed-by: David Chase <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>

Author: abner-chenc

unix/syscall_linux.go

@@ -12,6 +12,7 @@
 package unix
 
 import (
+	"debug/elf"
 	"encoding/binary"
 	"strconv"
 	"syscall"
@@ -1700,11 +1701,17 @@ func PtracePokeUser(pid int, addr uintptr, data []byte) (count int, err error) {
 }
 
 func PtraceGetRegs(pid int, regsout *PtraceRegs) (err error) {
-	return ptracePtr(PTRACE_GETREGS, pid, 0, unsafe.Pointer(regsout))
+	var iov Iovec
+	iov.Base = (*byte)(unsafe.Pointer(regsout))
+	iov.SetLen(int(unsafe.Sizeof(*regsout)))
+	return ptracePtr(PTRACE_GETREGSET, pid, uintptr(elf.NT_PRSTATUS), unsafe.Pointer(&iov))
 }
 
 func PtraceSetRegs(pid int, regs *PtraceRegs) (err error) {
-	return ptracePtr(PTRACE_SETREGS, pid, 0, unsafe.Pointer(regs))
+	var iov Iovec
+	iov.Base = (*byte)(unsafe.Pointer(regs))
+	iov.SetLen(int(unsafe.Sizeof(*regs)))
+	return ptracePtr(PTRACE_SETREGSET, pid, uintptr(elf.NT_PRSTATUS), unsafe.Pointer(&iov))
 }
 
 func PtraceSetOptions(pid int, options int) (err error) {