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// +build linux
/*
Copyright The containerd 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.
*/
package fifo
import (
"fmt"
"os"
"sync"
"syscall"
"github.com/pkg/errors"
)
//nolint:golint
const O_PATH = 010000000
type handle struct {
f *os.File
fd uintptr
dev uint64
ino uint64
closeOnce sync.Once
name string
}
func getHandle(fn string) (*handle, error) {
f, err := os.OpenFile(fn, O_PATH, 0)
if err != nil {
return nil, errors.Wrapf(err, "failed to open %v with O_PATH", fn)
}
var (
stat syscall.Stat_t
fd = f.Fd()
)
if err := syscall.Fstat(int(fd), &stat); err != nil {
f.Close()
return nil, errors.Wrapf(err, "failed to stat handle %v", fd)
}
h := &handle{
f: f,
name: fn,
//nolint:unconvert
dev: uint64(stat.Dev),
ino: stat.Ino,
fd: fd,
}
// check /proc just in case
if _, err := os.Stat(h.procPath()); err != nil {
f.Close()
return nil, errors.Wrapf(err, "couldn't stat %v", h.procPath())
}
return h, nil
}
func (h *handle) procPath() string {
return fmt.Sprintf("/proc/self/fd/%d", h.fd)
}
func (h *handle) Name() string {
return h.name
}
func (h *handle) Path() (string, error) {
var stat syscall.Stat_t
if err := syscall.Stat(h.procPath(), &stat); err != nil {
return "", errors.Wrapf(err, "path %v could not be statted", h.procPath())
}
//nolint:unconvert
if uint64(stat.Dev) != h.dev || stat.Ino != h.ino {
return "", errors.Errorf("failed to verify handle %v/%v %v/%v", stat.Dev, h.dev, stat.Ino, h.ino)
}
return h.procPath(), nil
}
func (h *handle) Close() error {
h.closeOnce.Do(func() {
h.f.Close()
})
return nil
}
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