github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/runsc/fsgofer/fsgofer_amd64_unsafe.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  // +build amd64
    16  
    17  package fsgofer
    18  
    19  import (
    20  	"unsafe"
    21  
    22  	"golang.org/x/sys/unix"
    23  	"github.com/SagerNet/gvisor/pkg/syserr"
    24  )
    25  
    26  func statAt(dirFd int, name string) (unix.Stat_t, error) {
    27  	nameBytes, err := unix.BytePtrFromString(name)
    28  	if err != nil {
    29  		return unix.Stat_t{}, err
    30  	}
    31  	namePtr := unsafe.Pointer(nameBytes)
    32  
    33  	var stat unix.Stat_t
    34  	statPtr := unsafe.Pointer(&stat)
    35  
    36  	if _, _, errno := unix.Syscall6(
    37  		unix.SYS_NEWFSTATAT,
    38  		uintptr(dirFd),
    39  		uintptr(namePtr),
    40  		uintptr(statPtr),
    41  		unix.AT_SYMLINK_NOFOLLOW,
    42  		0,
    43  		0); errno != 0 {
    44  
    45  		return unix.Stat_t{}, syserr.FromHost(errno).ToError()
    46  	}
    47  	return stat, nil
    48  }