54 lines
1.4 KiB
Go
54 lines
1.4 KiB
Go
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// +build linux
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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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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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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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