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bf692d47fb
This package was introduced inaf59752712as a utility package for devicemapper, which was removed in commitdc11d2a2d8(v25.0.0). It looks like there's no external consumers of this package, so we should consider removing it, but deprecating it first, just in case. Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
74 lines
1.9 KiB
Go
74 lines
1.9 KiB
Go
//go:build linux && cgo
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// Package loopback provides utilities to work with loopback devices.
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//
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// Deprecated: this package is deprecated and will be removed in the next release.
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package loopback // import "github.com/docker/docker/pkg/loopback"
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import (
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"context"
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"fmt"
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"os"
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"github.com/containerd/containerd/log"
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"golang.org/x/sys/unix"
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)
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func getLoopbackBackingFile(file *os.File) (uint64, uint64, error) {
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loopInfo, err := unix.IoctlLoopGetStatus64(int(file.Fd()))
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if err != nil {
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log.G(context.TODO()).Errorf("Error get loopback backing file: %s", err)
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return 0, 0, ErrGetLoopbackBackingFile
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}
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return loopInfo.Device, loopInfo.Inode, nil
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}
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// SetCapacity reloads the size for the loopback device.
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//
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// Deprecated: the loopback package is deprected and will be removed in the next release.
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func SetCapacity(file *os.File) error {
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if err := unix.IoctlSetInt(int(file.Fd()), unix.LOOP_SET_CAPACITY, 0); err != nil {
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log.G(context.TODO()).Errorf("Error loopbackSetCapacity: %s", err)
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return ErrSetCapacity
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}
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return nil
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}
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// FindLoopDeviceFor returns a loopback device file for the specified file which
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// is backing file of a loop back device.
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//
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// Deprecated: the loopback package is deprected and will be removed in the next release.
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func FindLoopDeviceFor(file *os.File) *os.File {
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var stat unix.Stat_t
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err := unix.Stat(file.Name(), &stat)
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if err != nil {
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return nil
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}
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targetInode := stat.Ino
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targetDevice := uint64(stat.Dev) //nolint: unconvert // the type is 32bit on mips
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for i := 0; true; i++ {
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path := fmt.Sprintf("/dev/loop%d", i)
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file, err := os.OpenFile(path, os.O_RDWR, 0)
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if err != nil {
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if os.IsNotExist(err) {
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return nil
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}
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// Ignore all errors until the first not-exist
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// we want to continue looking for the file
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continue
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}
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dev, inode, err := getLoopbackBackingFile(file)
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if err == nil && dev == targetDevice && inode == targetInode {
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return file
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}
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file.Close()
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}
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return nil
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}
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