98 lines
2.1 KiB
Go
98 lines
2.1 KiB
Go
// +build linux
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/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package fifo
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import (
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"fmt"
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"os"
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"sync"
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"syscall"
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"github.com/pkg/errors"
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)
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const O_PATH = 010000000
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type handle struct {
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f *os.File
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fd uintptr
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dev uint64
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ino uint64
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closeOnce sync.Once
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name string
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}
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func getHandle(fn string) (*handle, error) {
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f, err := os.OpenFile(fn, O_PATH, 0)
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if err != nil {
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return nil, errors.Wrapf(err, "failed to open %v with O_PATH", fn)
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}
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var (
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stat syscall.Stat_t
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fd = f.Fd()
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)
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if err := syscall.Fstat(int(fd), &stat); err != nil {
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f.Close()
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return nil, errors.Wrapf(err, "failed to stat handle %v", fd)
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}
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h := &handle{
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f: f,
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name: fn,
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dev: uint64(stat.Dev),
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ino: stat.Ino,
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fd: fd,
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}
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// check /proc just in case
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if _, err := os.Stat(h.procPath()); err != nil {
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f.Close()
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return nil, errors.Wrapf(err, "couldn't stat %v", h.procPath())
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}
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return h, nil
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}
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func (h *handle) procPath() string {
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return fmt.Sprintf("/proc/self/fd/%d", h.fd)
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}
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func (h *handle) Name() string {
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return h.name
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}
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func (h *handle) Path() (string, error) {
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var stat syscall.Stat_t
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if err := syscall.Stat(h.procPath(), &stat); err != nil {
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return "", errors.Wrapf(err, "path %v could not be statted", h.procPath())
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}
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if uint64(stat.Dev) != h.dev || stat.Ino != h.ino {
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return "", errors.Errorf("failed to verify handle %v/%v %v/%v", stat.Dev, h.dev, stat.Ino, h.ino)
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}
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return h.procPath(), nil
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}
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func (h *handle) Close() error {
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h.closeOnce.Do(func() {
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h.f.Close()
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})
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return nil
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}
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