gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/pkg/sentry/syscalls/linux/sys_rseq.go (about)

     1  // Copyright 2019 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  package linux
    16  
    17  import (
    18  	"gvisor.dev/gvisor/pkg/abi/linux"
    19  	"gvisor.dev/gvisor/pkg/errors/linuxerr"
    20  	"gvisor.dev/gvisor/pkg/sentry/arch"
    21  	"gvisor.dev/gvisor/pkg/sentry/kernel"
    22  )
    23  
    24  // RSeq implements syscall rseq(2).
    25  func RSeq(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
    26  	addr := args[0].Pointer()
    27  	length := args[1].Uint()
    28  	flags := args[2].Int()
    29  	signature := args[3].Uint()
    30  
    31  	if !t.RSeqAvailable() {
    32  		// Event for applications that want rseq on a configuration
    33  		// that doesn't support them.
    34  		t.Kernel().EmitUnimplementedEvent(t, sysno)
    35  		return 0, nil, linuxerr.ENOSYS
    36  	}
    37  
    38  	switch flags {
    39  	case 0:
    40  		// Register.
    41  		return 0, nil, t.SetRSeq(addr, length, signature)
    42  	case linux.RSEQ_FLAG_UNREGISTER:
    43  		return 0, nil, t.ClearRSeq(addr, length, signature)
    44  	default:
    45  		// Unknown flag.
    46  		return 0, nil, linuxerr.EINVAL
    47  	}
    48  }