gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/pkg/sentry/fsimpl/host/host_unsafe.go (about)

     1  // Copyright 2021 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 host
    16  
    17  import (
    18  	"unsafe"
    19  
    20  	"golang.org/x/sys/unix"
    21  	"gvisor.dev/gvisor/pkg/abi/linux"
    22  )
    23  
    24  func ioctlFionread(fd int) (uint32, error) {
    25  	var v uint32
    26  	if _, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(fd), linux.FIONREAD, uintptr(unsafe.Pointer(&v))); errno != 0 {
    27  		return 0, errno
    28  	}
    29  	return v, nil
    30  }