github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/memutil/memfd_linux_unsafe.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  // +build linux
    16  
    17  package memutil
    18  
    19  import (
    20  	"fmt"
    21  	"unsafe"
    22  
    23  	"golang.org/x/sys/unix"
    24  )
    25  
    26  // CreateMemFD creates a memfd file and returns the fd.
    27  func CreateMemFD(name string, flags int) (int, error) {
    28  	p, err := unix.BytePtrFromString(name)
    29  	if err != nil {
    30  		return -1, err
    31  	}
    32  	fd, _, e := unix.Syscall(unix.SYS_MEMFD_CREATE, uintptr(unsafe.Pointer(p)), uintptr(flags), 0)
    33  	if e != 0 {
    34  		if e == unix.ENOSYS {
    35  			return -1, fmt.Errorf("memfd_create(2) is not implemented. Check that you have Linux 3.17 or higher")
    36  		}
    37  		return -1, e
    38  	}
    39  	return int(fd), nil
    40  }