github.com/MerlinKodo/gvisor@v0.0.0-20231110090155-957f62ecf90e/pkg/sentry/syscalls/linux/sys_tls_amd64.go (about)

     1  // Copyright 2018 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  //go:build amd64
    16  // +build amd64
    17  
    18  package linux
    19  
    20  import (
    21  	"github.com/MerlinKodo/gvisor/pkg/abi/linux"
    22  	"github.com/MerlinKodo/gvisor/pkg/errors/linuxerr"
    23  	"github.com/MerlinKodo/gvisor/pkg/marshal/primitive"
    24  	"github.com/MerlinKodo/gvisor/pkg/sentry/arch"
    25  	"github.com/MerlinKodo/gvisor/pkg/sentry/kernel"
    26  )
    27  
    28  // ArchPrctl implements linux syscall arch_prctl(2).
    29  // It sets architecture-specific process or thread state for t.
    30  func ArchPrctl(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
    31  	switch args[0].Int() {
    32  	case linux.ARCH_GET_FS:
    33  		addr := args[1].Pointer()
    34  		fsbase := t.Arch().TLS()
    35  		switch t.Arch().Width() {
    36  		case 8:
    37  			if _, err := primitive.CopyUint64Out(t, addr, uint64(fsbase)); err != nil {
    38  				return 0, nil, err
    39  			}
    40  		default:
    41  			return 0, nil, linuxerr.ENOSYS
    42  		}
    43  	case linux.ARCH_SET_FS:
    44  		fsbase := args[1].Uint64()
    45  		if !t.Arch().SetTLS(uintptr(fsbase)) {
    46  			return 0, nil, linuxerr.EPERM
    47  		}
    48  	case linux.ARCH_GET_GS, linux.ARCH_SET_GS:
    49  		t.Kernel().EmitUnimplementedEvent(t, sysno)
    50  		fallthrough
    51  	default:
    52  		return 0, nil, linuxerr.EINVAL
    53  	}
    54  
    55  	return 0, nil, nil
    56  }