Stat uses Windows FindFirstFile + CreateFile to gather symlink
information - FindFirstFile determines if file is a symlink,
and then CreateFile follows symlink to capture target details.
Lstat only uses FindFirstFile.
This CL replaces current approach with just a call to CreateFile.
Lstat uses FILE_FLAG_OPEN_REPARSE_POINT flag, that instructs
CreateFile not to follow symlink. Other than that both Stat and
Lstat look the same now. New code is simpler.
CreateFile + GetFileInformationByHandle (unlike FindFirstFile)
does not report reparse tag of a file. I tried to ignore reparse
tag altogether. And it works for symlinks and mount points.
Unfortunately (see https://github.com/moby/moby/issues/37026),
files on deduped disk volumes are reported with
FILE_ATTRIBUTE_REPARSE_POINT attribute set and reparse tag set
to IO_REPARSE_TAG_DEDUP. So, if we ignore reparse tag, Lstat
interprets deduped volume files as symlinks. That is incorrect.
So I had to add GetFileInformationByHandleEx call to gather
reparse tag after calling CreateFile and GetFileInformationByHandle.
Fixes #27225
Fixes #27515
Change-Id: If60233bcf18836c147597cc17450d82f3f88c623
Reviewed-on: https://go-review.googlesource.com/c/143578
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Kirill Kolyshkin <kolyshkin@gmail.com>
package windows
-//go:generate go run $GOROOT/src/syscall/mksyscall_windows.go -output zsyscall_windows.go syscall_windows.go security_windows.go psapi_windows.go
+//go:generate go run $GOROOT/src/syscall/mksyscall_windows.go -output zsyscall_windows.go syscall_windows.go security_windows.go psapi_windows.go symlink_windows.go
// symlink support for CreateSymbolicLink() starting with Windows 10 (1703, v10.0.14972)
SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE = 0x2
+
+ // FileInformationClass values
+ FileBasicInfo = 0 // FILE_BASIC_INFO
+ FileStandardInfo = 1 // FILE_STANDARD_INFO
+ FileNameInfo = 2 // FILE_NAME_INFO
+ FileStreamInfo = 7 // FILE_STREAM_INFO
+ FileCompressionInfo = 8 // FILE_COMPRESSION_INFO
+ FileAttributeTagInfo = 9 // FILE_ATTRIBUTE_TAG_INFO
+ FileIdBothDirectoryInfo = 0xa // FILE_ID_BOTH_DIR_INFO
+ FileIdBothDirectoryRestartInfo = 0xb // FILE_ID_BOTH_DIR_INFO
+ FileRemoteProtocolInfo = 0xd // FILE_REMOTE_PROTOCOL_INFO
+ FileFullDirectoryInfo = 0xe // FILE_FULL_DIR_INFO
+ FileFullDirectoryRestartInfo = 0xf // FILE_FULL_DIR_INFO
+ FileStorageInfo = 0x10 // FILE_STORAGE_INFO
+ FileAlignmentInfo = 0x11 // FILE_ALIGNMENT_INFO
+ FileIdInfo = 0x12 // FILE_ID_INFO
+ FileIdExtdDirectoryInfo = 0x13 // FILE_ID_EXTD_DIR_INFO
+ FileIdExtdDirectoryRestartInfo = 0x14 // FILE_ID_EXTD_DIR_INFO
)
+
+type FILE_ATTRIBUTE_TAG_INFO struct {
+ FileAttributes uint32
+ ReparseTag uint32
+}
+
+//sys GetFileInformationByHandleEx(handle syscall.Handle, class uint32, info *byte, bufsize uint32) (err error)
moduserenv = syscall.NewLazyDLL(sysdll.Add("userenv.dll"))
modpsapi = syscall.NewLazyDLL(sysdll.Add("psapi.dll"))
- procGetAdaptersAddresses = modiphlpapi.NewProc("GetAdaptersAddresses")
- procGetComputerNameExW = modkernel32.NewProc("GetComputerNameExW")
- procMoveFileExW = modkernel32.NewProc("MoveFileExW")
- procGetModuleFileNameW = modkernel32.NewProc("GetModuleFileNameW")
- procWSASocketW = modws2_32.NewProc("WSASocketW")
- procGetACP = modkernel32.NewProc("GetACP")
- procGetConsoleCP = modkernel32.NewProc("GetConsoleCP")
- procMultiByteToWideChar = modkernel32.NewProc("MultiByteToWideChar")
- procGetCurrentThread = modkernel32.NewProc("GetCurrentThread")
- procNetShareAdd = modnetapi32.NewProc("NetShareAdd")
- procNetShareDel = modnetapi32.NewProc("NetShareDel")
- procGetFinalPathNameByHandleW = modkernel32.NewProc("GetFinalPathNameByHandleW")
- procImpersonateSelf = modadvapi32.NewProc("ImpersonateSelf")
- procRevertToSelf = modadvapi32.NewProc("RevertToSelf")
- procOpenThreadToken = modadvapi32.NewProc("OpenThreadToken")
- procLookupPrivilegeValueW = modadvapi32.NewProc("LookupPrivilegeValueW")
- procAdjustTokenPrivileges = modadvapi32.NewProc("AdjustTokenPrivileges")
- procDuplicateTokenEx = modadvapi32.NewProc("DuplicateTokenEx")
- procSetTokenInformation = modadvapi32.NewProc("SetTokenInformation")
- procGetProfilesDirectoryW = moduserenv.NewProc("GetProfilesDirectoryW")
- procNetUserGetLocalGroups = modnetapi32.NewProc("NetUserGetLocalGroups")
- procGetProcessMemoryInfo = modpsapi.NewProc("GetProcessMemoryInfo")
+ procGetAdaptersAddresses = modiphlpapi.NewProc("GetAdaptersAddresses")
+ procGetComputerNameExW = modkernel32.NewProc("GetComputerNameExW")
+ procMoveFileExW = modkernel32.NewProc("MoveFileExW")
+ procGetModuleFileNameW = modkernel32.NewProc("GetModuleFileNameW")
+ procWSASocketW = modws2_32.NewProc("WSASocketW")
+ procGetACP = modkernel32.NewProc("GetACP")
+ procGetConsoleCP = modkernel32.NewProc("GetConsoleCP")
+ procMultiByteToWideChar = modkernel32.NewProc("MultiByteToWideChar")
+ procGetCurrentThread = modkernel32.NewProc("GetCurrentThread")
+ procNetShareAdd = modnetapi32.NewProc("NetShareAdd")
+ procNetShareDel = modnetapi32.NewProc("NetShareDel")
+ procGetFinalPathNameByHandleW = modkernel32.NewProc("GetFinalPathNameByHandleW")
+ procImpersonateSelf = modadvapi32.NewProc("ImpersonateSelf")
+ procRevertToSelf = modadvapi32.NewProc("RevertToSelf")
+ procOpenThreadToken = modadvapi32.NewProc("OpenThreadToken")
+ procLookupPrivilegeValueW = modadvapi32.NewProc("LookupPrivilegeValueW")
+ procAdjustTokenPrivileges = modadvapi32.NewProc("AdjustTokenPrivileges")
+ procDuplicateTokenEx = modadvapi32.NewProc("DuplicateTokenEx")
+ procSetTokenInformation = modadvapi32.NewProc("SetTokenInformation")
+ procGetProfilesDirectoryW = moduserenv.NewProc("GetProfilesDirectoryW")
+ procNetUserGetLocalGroups = modnetapi32.NewProc("NetUserGetLocalGroups")
+ procGetProcessMemoryInfo = modpsapi.NewProc("GetProcessMemoryInfo")
+ procGetFileInformationByHandleEx = modkernel32.NewProc("GetFileInformationByHandleEx")
)
func GetAdaptersAddresses(family uint32, flags uint32, reserved uintptr, adapterAddresses *IpAdapterAddresses, sizePointer *uint32) (errcode error) {
}
return
}
+
+func GetFileInformationByHandleEx(handle syscall.Handle, class uint32, info *byte, bufsize uint32) (err error) {
+ r1, _, e1 := syscall.Syscall6(procGetFileInformationByHandleEx.Addr(), 4, uintptr(handle), uintptr(class), uintptr(unsafe.Pointer(info)), uintptr(bufsize), 0, 0)
+ if r1 == 0 {
+ if e1 != 0 {
+ err = errnoErr(e1)
+ } else {
+ err = syscall.EINVAL
+ }
+ }
+ return
+}
// see issue 27225 for details
func TestSymlinkWithTrailingSlash(t *testing.T) {
- if runtime.GOOS == "windows" {
- t.Skip("skipping on windows; issue 27225")
- }
-
testenv.MustHaveSymlink(t)
tmpdir, err := ioutil.TempDir("", "TestSymlinkWithTrailingSlash")
}
dirlinkWithSlash := dirlink + string(os.PathSeparator)
- testDirStats(t, dirlinkWithSlash)
+ if runtime.GOOS == "windows" {
+ testSymlinkStats(t, dirlinkWithSlash, true)
+ } else {
+ testDirStats(t, dirlinkWithSlash)
+ }
fi1, err := os.Stat(dir)
if err != nil {
package os
import (
+ "internal/syscall/windows"
"syscall"
+ "unsafe"
)
// isNulName returns true if name is NUL file name.
return fs, err
}
-// statNolog implements Stat for Windows.
-func statNolog(name string) (FileInfo, error) {
+// stat implements both Stat and Lstat of a file.
+func stat(funcname, name string, createFileAttrs uint32) (FileInfo, error) {
if len(name) == 0 {
- return nil, &PathError{"Stat", name, syscall.Errno(syscall.ERROR_PATH_NOT_FOUND)}
+ return nil, &PathError{funcname, name, syscall.Errno(syscall.ERROR_PATH_NOT_FOUND)}
}
if isNulName(name) {
return &devNullStat, nil
}
namep, err := syscall.UTF16PtrFromString(fixLongPath(name))
if err != nil {
- return nil, &PathError{"Stat", name, err}
+ return nil, &PathError{funcname, name, err}
}
- fs, err := newFileStatFromGetFileAttributesExOrFindFirstFile(name, namep)
- if err != nil {
- return nil, err
+
+ // Try GetFileAttributesEx first, because it is faster than CreateFile.
+ // See https://golang.org/issues/19922#issuecomment-300031421 for details.
+ var fa syscall.Win32FileAttributeData
+ err = syscall.GetFileAttributesEx(namep, syscall.GetFileExInfoStandard, (*byte)(unsafe.Pointer(&fa)))
+ if err == nil && fa.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT == 0 {
+ // Not a symlink.
+ fs := &fileStat{
+ path: name,
+ FileAttributes: fa.FileAttributes,
+ CreationTime: fa.CreationTime,
+ LastAccessTime: fa.LastAccessTime,
+ LastWriteTime: fa.LastWriteTime,
+ FileSizeHigh: fa.FileSizeHigh,
+ FileSizeLow: fa.FileSizeLow,
+ }
+ // Gather full path to be used by os.SameFile later.
+ if !isAbs(fs.path) {
+ fs.path, err = syscall.FullPath(fs.path)
+ if err != nil {
+ return nil, &PathError{"FullPath", name, err}
+ }
+ }
+ fs.name = basename(name)
+ return fs, nil
}
- if !fs.isSymlink() {
- err = fs.updatePathAndName(name)
+ // GetFileAttributesEx fails with ERROR_SHARING_VIOLATION error for
+ // files, like c:\pagefile.sys. Use FindFirstFile for such files.
+ if err == windows.ERROR_SHARING_VIOLATION {
+ var fd syscall.Win32finddata
+ sh, err := syscall.FindFirstFile(namep, &fd)
if err != nil {
- return nil, err
+ return nil, &PathError{"FindFirstFile", name, err}
}
- return fs, nil
+ syscall.FindClose(sh)
+ return newFileStatFromWin32finddata(&fd), nil
}
- // Use Windows I/O manager to dereference the symbolic link, as per
- // https://blogs.msdn.microsoft.com/oldnewthing/20100212-00/?p=14963/
+
+ // Finally use CreateFile.
h, err := syscall.CreateFile(namep, 0, 0, nil,
- syscall.OPEN_EXISTING, syscall.FILE_FLAG_BACKUP_SEMANTICS, 0)
+ syscall.OPEN_EXISTING, createFileAttrs, 0)
if err != nil {
return nil, &PathError{"CreateFile", name, err}
}
return newFileStatFromGetFileInformationByHandle(name, h)
}
+// statNolog implements Stat for Windows.
+func statNolog(name string) (FileInfo, error) {
+ return stat("Stat", name, syscall.FILE_FLAG_BACKUP_SEMANTICS)
+}
+
// lstatNolog implements Lstat for Windows.
func lstatNolog(name string) (FileInfo, error) {
- if len(name) == 0 {
- return nil, &PathError{"Lstat", name, syscall.Errno(syscall.ERROR_PATH_NOT_FOUND)}
- }
- if isNulName(name) {
- return &devNullStat, nil
- }
- namep, err := syscall.UTF16PtrFromString(fixLongPath(name))
- if err != nil {
- return nil, &PathError{"Lstat", name, err}
- }
- fs, err := newFileStatFromGetFileAttributesExOrFindFirstFile(name, namep)
- if err != nil {
- return nil, err
- }
- err = fs.updatePathAndName(name)
- if err != nil {
- return nil, err
- }
- return fs, nil
+ attrs := uint32(syscall.FILE_FLAG_BACKUP_SEMANTICS)
+ // Use FILE_FLAG_OPEN_REPARSE_POINT, otherwise CreateFile will follow symlink.
+ // See https://docs.microsoft.com/en-us/windows/desktop/FileIO/symbolic-link-effects-on-file-systems-functions#createfile-and-createfiletransacted
+ attrs |= syscall.FILE_FLAG_OPEN_REPARSE_POINT
+ return stat("Lstat", name, attrs)
}
if err != nil {
return nil, &PathError{"GetFileInformationByHandle", path, err}
}
+
+ var ti windows.FILE_ATTRIBUTE_TAG_INFO
+ err = windows.GetFileInformationByHandleEx(h, windows.FileAttributeTagInfo, (*byte)(unsafe.Pointer(&ti)), uint32(unsafe.Sizeof(ti)))
+ if err != nil {
+ return nil, &PathError{"GetFileInformationByHandleEx", path, err}
+ }
+
return &fileStat{
name: basename(path),
FileAttributes: d.FileAttributes,
vol: d.VolumeSerialNumber,
idxhi: d.FileIndexHigh,
idxlo: d.FileIndexLow,
+ Reserved0: ti.ReparseTag,
// fileStat.path is used by os.SameFile to decide if it needs
// to fetch vol, idxhi and idxlo. But these are already set,
// so set fileStat.path to "" to prevent os.SameFile doing it again.
}
}
-// newFileStatFromGetFileAttributesExOrFindFirstFile calls GetFileAttributesEx
-// and FindFirstFile to gather all required information about the provided file path pathp.
-func newFileStatFromGetFileAttributesExOrFindFirstFile(path string, pathp *uint16) (*fileStat, error) {
- // As suggested by Microsoft, use GetFileAttributes() to acquire the file information,
- // and if it's a reparse point use FindFirstFile() to get the tag:
- // https://msdn.microsoft.com/en-us/library/windows/desktop/aa363940(v=vs.85).aspx
- // Notice that always calling FindFirstFile can create performance problems
- // (https://golang.org/issues/19922#issuecomment-300031421)
- var fa syscall.Win32FileAttributeData
- err := syscall.GetFileAttributesEx(pathp, syscall.GetFileExInfoStandard, (*byte)(unsafe.Pointer(&fa)))
- if err == nil && fa.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT == 0 {
- // Not a symlink.
- return &fileStat{
- FileAttributes: fa.FileAttributes,
- CreationTime: fa.CreationTime,
- LastAccessTime: fa.LastAccessTime,
- LastWriteTime: fa.LastWriteTime,
- FileSizeHigh: fa.FileSizeHigh,
- FileSizeLow: fa.FileSizeLow,
- }, nil
- }
- // GetFileAttributesEx returns ERROR_INVALID_NAME if called
- // for invalid file name like "*.txt". Do not attempt to call
- // FindFirstFile with "*.txt", because FindFirstFile will
- // succeed. So just return ERROR_INVALID_NAME instead.
- // see https://golang.org/issue/24999 for details.
- if errno, _ := err.(syscall.Errno); errno == windows.ERROR_INVALID_NAME {
- return nil, &PathError{"GetFileAttributesEx", path, err}
- }
- // We might have symlink here. But some directories also have
- // FileAttributes FILE_ATTRIBUTE_REPARSE_POINT bit set.
- // For example, OneDrive directory is like that
- // (see golang.org/issue/22579 for details).
- // So use FindFirstFile instead to distinguish directories like
- // OneDrive from real symlinks (see instructions described at
- // https://blogs.msdn.microsoft.com/oldnewthing/20100212-00/?p=14963/
- // and in particular bits about using both FileAttributes and
- // Reserved0 fields).
- var fd syscall.Win32finddata
- sh, err := syscall.FindFirstFile(pathp, &fd)
- if err != nil {
- return nil, &PathError{"FindFirstFile", path, err}
- }
- syscall.FindClose(sh)
-
- return newFileStatFromWin32finddata(&fd), nil
-}
-
-func (fs *fileStat) updatePathAndName(name string) error {
- fs.path = name
- if !isAbs(fs.path) {
- var err error
- fs.path, err = syscall.FullPath(fs.path)
- if err != nil {
- return &PathError{"FullPath", name, err}
- }
- }
- fs.name = basename(name)
- return nil
-}
-
func (fs *fileStat) isSymlink() bool {
// Use instructions described at
// https://blogs.msdn.microsoft.com/oldnewthing/20100212-00/?p=14963/