73 lines
2 KiB
Go
73 lines
2 KiB
Go
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// +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 testutil
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import (
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"io/ioutil"
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"os"
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"os/exec"
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"strings"
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"github.com/pkg/errors"
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"github.com/sirupsen/logrus"
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)
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// NewLoopback creates a loopback device, and returns its device name (/dev/loopX), and its clean-up function.
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func NewLoopback(size int64) (string, func() error, error) {
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// create temporary file for the disk image
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file, err := ioutil.TempFile("", "containerd-test-loopback")
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if err != nil {
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return "", nil, errors.Wrap(err, "could not create temporary file for loopback")
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}
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if err := file.Truncate(size); err != nil {
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file.Close()
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os.Remove(file.Name())
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return "", nil, errors.Wrap(err, "failed to resize temp file")
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}
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file.Close()
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// create device
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losetup := exec.Command("losetup", "--find", "--show", file.Name())
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p, err := losetup.Output()
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if err != nil {
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os.Remove(file.Name())
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return "", nil, errors.Wrap(err, "loopback setup failed")
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}
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deviceName := strings.TrimSpace(string(p))
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logrus.Debugf("Created loop device %s (using %s)", deviceName, file.Name())
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cleanup := func() error {
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// detach device
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logrus.Debugf("Removing loop device %s", deviceName)
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losetup := exec.Command("losetup", "--detach", deviceName)
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err := losetup.Run()
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if err != nil {
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return errors.Wrapf(err, "Could not remove loop device %s", deviceName)
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}
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// remove file
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logrus.Debugf("Removing temporary file %s", file.Name())
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return os.Remove(file.Name())
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}
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return deviceName, cleanup, nil
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}
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