rclone/lib/file/file_windows.go

103 lines
3.5 KiB
Go

//go:build windows
package file
import (
"errors"
"os"
"path/filepath"
"regexp"
"syscall"
)
// OpenFile is the generalized open call; most users will use Open or Create
// instead. It opens the named file with specified flag (O_RDONLY etc.) and
// perm (before umask), if applicable. If successful, methods on the returned
// File can be used for I/O. If there is an error, it will be of type
// *PathError.
//
// Under both Unix and Windows this will allow open files to be
// renamed and or deleted.
func OpenFile(path string, mode int, perm os.FileMode) (*os.File, error) {
// This code copied from syscall_windows.go in the go source and then
// modified to support renaming and deleting open files by adding
// FILE_SHARE_DELETE.
//
// https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-createfilea#file_share_delete
if len(path) == 0 {
return nil, syscall.ERROR_FILE_NOT_FOUND
}
pathp, err := syscall.UTF16PtrFromString(path)
if err != nil {
return nil, err
}
var access uint32
switch mode & (syscall.O_RDONLY | syscall.O_WRONLY | syscall.O_RDWR) {
case syscall.O_RDONLY:
access = syscall.GENERIC_READ
case syscall.O_WRONLY:
access = syscall.GENERIC_WRITE
case syscall.O_RDWR:
access = syscall.GENERIC_READ | syscall.GENERIC_WRITE
}
if mode&syscall.O_CREAT != 0 {
access |= syscall.GENERIC_WRITE
}
if mode&syscall.O_APPEND != 0 {
access &^= syscall.GENERIC_WRITE
access |= syscall.FILE_APPEND_DATA
}
sharemode := uint32(syscall.FILE_SHARE_READ | syscall.FILE_SHARE_WRITE | syscall.FILE_SHARE_DELETE)
var createmode uint32
switch {
case mode&(syscall.O_CREAT|syscall.O_EXCL) == (syscall.O_CREAT | syscall.O_EXCL):
createmode = syscall.CREATE_NEW
case mode&(syscall.O_CREAT|syscall.O_TRUNC) == (syscall.O_CREAT | syscall.O_TRUNC):
createmode = syscall.CREATE_ALWAYS
case mode&syscall.O_CREAT == syscall.O_CREAT:
createmode = syscall.OPEN_ALWAYS
case mode&syscall.O_TRUNC == syscall.O_TRUNC:
createmode = syscall.TRUNCATE_EXISTING
default:
createmode = syscall.OPEN_EXISTING
}
h, e := syscall.CreateFile(pathp, access, sharemode, nil, createmode, syscall.FILE_ATTRIBUTE_NORMAL, 0)
if e != nil {
return nil, e
}
return os.NewFile(uintptr(h), path), nil
}
// IsReserved checks if path contains a reserved name
func IsReserved(path string) error {
if path == "" {
return errors.New("path is empty")
}
base := filepath.Base(path)
// If the path is empty or reduces to ".", Base returns ".".
if base == "." {
return errors.New("path is '.'")
}
// If the path consists entirely of separators, Base returns a single separator.
if base == string(filepath.Separator) {
return errors.New("path consists entirely of separators")
}
// Do not end a file or directory name with a space or a period. Although the underlying
// file system may support such names, the Windows shell and user interface does not.
// (https://docs.microsoft.com/en-gb/windows/win32/fileio/naming-a-file)
suffix := base[len(base)-1]
switch suffix {
case ' ':
return errors.New("base file name ends with a space")
case '.':
return errors.New("base file name ends with a period")
}
// Do not use names of legacy (DOS) devices, not even as basename without extension,
// as this will refer to the actual device.
// (https://docs.microsoft.com/en-gb/windows/win32/fileio/naming-a-file)
if reserved, _ := regexp.MatchString(`^(?i:con|prn|aux|nul|com[1-9]|lpt[1-9])(?:\.|$)`, base); reserved {
return errors.New("base file name is reserved windows device name (CON, PRN, AUX, NUL, COM[1-9], LPT[1-9])")
}
return nil
}