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// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//+build amd64
package linux
import (
"syscall"
"gvisor.googlesource.com/gvisor/pkg/abi/linux"
"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
)
// ArchPrctl implements linux syscall arch_prctl(2).
// It sets architecture-specific process or thread state for t.
func ArchPrctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
switch args[0].Int() {
case linux.ARCH_GET_FS:
addr := args[1].Pointer()
fsbase := t.Arch().TLS()
_, err := t.CopyOut(addr, uint64(fsbase))
if err != nil {
return 0, nil, err
}
case linux.ARCH_SET_FS:
fsbase := args[1].Uint64()
if !t.Arch().SetTLS(uintptr(fsbase)) {
return 0, nil, syscall.EPERM
}
case linux.ARCH_GET_GS, linux.ARCH_SET_GS:
t.Kernel().EmitUnimplementedEvent(t)
fallthrough
default:
return 0, nil, syscall.EINVAL
}
return 0, nil, nil
}
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