mirror of https://github.com/restic/restic.git
80 lines
2.2 KiB
Go
80 lines
2.2 KiB
Go
package fs
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import (
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"math/rand"
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"os"
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"path/filepath"
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"strconv"
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"strings"
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"time"
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"golang.org/x/sys/windows"
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)
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// fixpath returns an absolute path on windows, so restic can open long file
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// names.
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func fixpath(name string) string {
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abspath, err := filepath.Abs(name)
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if err == nil {
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// Check if \\?\UNC\ already exist
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if strings.HasPrefix(abspath, `\\?\UNC\`) {
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return abspath
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}
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// Check if \\?\ already exist
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if strings.HasPrefix(abspath, `\\?\`) {
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return abspath
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}
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// Check if path starts with \\
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if strings.HasPrefix(abspath, `\\`) {
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return strings.Replace(abspath, `\\`, `\\?\UNC\`, 1)
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}
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// Normal path
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return `\\?\` + abspath
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}
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return name
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}
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// TempFile creates a temporary file which is marked as delete-on-close
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func TempFile(dir, prefix string) (f *os.File, err error) {
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// slightly modified implementation of os.CreateTemp(dir, prefix) to allow us to add
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// the FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE flags.
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// These provide two large benefits:
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// FILE_ATTRIBUTE_TEMPORARY tells Windows to keep the file in memory only if possible
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// which reduces the amount of unnecessary disk writes.
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// FILE_FLAG_DELETE_ON_CLOSE instructs Windows to automatically delete the file once
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// all file descriptors are closed.
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if dir == "" {
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dir = os.TempDir()
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}
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access := uint32(windows.GENERIC_READ | windows.GENERIC_WRITE)
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creation := uint32(windows.CREATE_NEW)
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share := uint32(0) // prevent other processes from accessing the file
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flags := uint32(windows.FILE_ATTRIBUTE_TEMPORARY | windows.FILE_FLAG_DELETE_ON_CLOSE)
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rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
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for i := 0; i < 10000; i++ {
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randSuffix := strconv.Itoa(int(1e9 + rnd.Intn(1e9)%1e9))[1:]
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path := filepath.Join(dir, prefix+randSuffix)
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ptr, err := windows.UTF16PtrFromString(path)
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if err != nil {
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return nil, err
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}
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h, err := windows.CreateFile(ptr, access, share, nil, creation, flags, 0)
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if os.IsExist(err) {
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continue
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}
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return os.NewFile(uintptr(h), path), err
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}
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// Proper error handling is still to do
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return nil, os.ErrExist
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}
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// Chmod changes the mode of the named file to mode.
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func Chmod(name string, mode os.FileMode) error {
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return os.Chmod(fixpath(name), mode)
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}
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