pcontrol_linux_arm64.go

//go:build linux && arm64
// +build linux,arm64

package pcontrol

import (
	"encoding/binary"

	"gitlab.com/tozd/go/errors"
	"golang.org/x/sys/unix"
)

var nativeEndian = binary.LittleEndian //nolint:gochecknoglobals

// Call a syscall (svc #0) and a breakpoint (brk #0). We do not use ptrace single step but ptrace cont
// until a breakpoint so that it is easier to allow signal handlers in process to run.
var syscallInstruction = [...]byte{0x01, 0x00, 0x00, 0xD4, 0x00, 0x00, 0x20, 0xD4} //nolint:gochecknoglobals

type processRegs unix.PtraceRegs

func getProcessRegs(pid int) (processRegs, errors.E) {
	var regs unix.PtraceRegs
	err := unix.PtraceGetRegs(pid, &regs)
	if err != nil {
		return processRegs{}, errors.WithMessage(err, "ptrace get regs") //nolint:exhaustruct
	}
	return processRegs(regs), nil
}

func setProcessRegs(pid int, regs *processRegs) errors.E {
	err := unix.PtraceSetRegs(pid, (*unix.PtraceRegs)(regs))
	return errors.WithMessage(err, "ptrace set regs")
}

func newSyscallRegs(originalRegs *processRegs, ip uint64, call int, arg0, arg1, arg2, arg3, arg4, arg5 uint64) processRegs {
	newRegs := *originalRegs
	(*unix.PtraceRegs)(&newRegs).SetPC(ip)
	newRegs.Regs[0] = arg0
	newRegs.Regs[1] = arg1
	newRegs.Regs[2] = arg2
	newRegs.Regs[3] = arg3
	newRegs.Regs[4] = arg4
	newRegs.Regs[5] = arg5
	newRegs.Regs[8] = uint64(call) //nolint:gosec
	return newRegs
}

func getSyscallResultReg(regs *processRegs) uint64 {
	return regs.Regs[0]
}

func getProcessPC(regs *processRegs) uint64 {
	return (*unix.PtraceRegs)(regs).PC()
}