github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/sentry/platform/ptrace/ptrace_arm64_unsafe.go (about)

     1  // Copyright 2020 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // +build arm64
    16  
    17  package ptrace
    18  
    19  import (
    20  	"unsafe"
    21  
    22  	"golang.org/x/sys/unix"
    23  	"github.com/SagerNet/gvisor/pkg/abi/linux"
    24  )
    25  
    26  // getTLS gets the thread local storage register.
    27  func (t *thread) getTLS(tls *uint64) error {
    28  	iovec := unix.Iovec{
    29  		Base: (*byte)(unsafe.Pointer(tls)),
    30  		Len:  uint64(unsafe.Sizeof(*tls)),
    31  	}
    32  	_, _, errno := unix.RawSyscall6(
    33  		unix.SYS_PTRACE,
    34  		unix.PTRACE_GETREGSET,
    35  		uintptr(t.tid),
    36  		linux.NT_ARM_TLS,
    37  		uintptr(unsafe.Pointer(&iovec)),
    38  		0, 0)
    39  	if errno != 0 {
    40  		return errno
    41  	}
    42  	return nil
    43  }
    44  
    45  // setTLS sets the thread local storage register.
    46  func (t *thread) setTLS(tls *uint64) error {
    47  	iovec := unix.Iovec{
    48  		Base: (*byte)(unsafe.Pointer(tls)),
    49  		Len:  uint64(unsafe.Sizeof(*tls)),
    50  	}
    51  	_, _, errno := unix.RawSyscall6(
    52  		unix.SYS_PTRACE,
    53  		unix.PTRACE_SETREGSET,
    54  		uintptr(t.tid),
    55  		linux.NT_ARM_TLS,
    56  		uintptr(unsafe.Pointer(&iovec)),
    57  		0, 0)
    58  	if errno != 0 {
    59  		return errno
    60  	}
    61  	return nil
    62  }