1 files changed, 91 insertions, 0 deletions
diff --git a/src/internal/syscall/windows/reparse_windows.go b/src/internal/syscall/windows/reparse_windows.go
new file mode 100644
index 0000000..02f32c6
--- /dev/null
+++ b/src/internal/syscall/windows/reparse_windows.go
@@ -0,0 +1,91 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package windows
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const (
+	FSCTL_SET_REPARSE_POINT    = 0x000900A4
+	IO_REPARSE_TAG_MOUNT_POINT = 0xA0000003
+	IO_REPARSE_TAG_DEDUP       = 0x80000013
+
+	SYMLINK_FLAG_RELATIVE = 1
+)
+
+// These structures are described
+// in https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-fscc/ca069dad-ed16-42aa-b057-b6b207f447cc
+// and https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-fscc/b41f1cbf-10df-4a47-98d4-1c52a833d913.
+
+type REPARSE_DATA_BUFFER struct {
+	ReparseTag        uint32
+	ReparseDataLength uint16
+	Reserved          uint16
+	DUMMYUNIONNAME    byte
+}
+
+// REPARSE_DATA_BUFFER_HEADER is a common part of REPARSE_DATA_BUFFER structure.
+type REPARSE_DATA_BUFFER_HEADER struct {
+	ReparseTag uint32
+	// The size, in bytes, of the reparse data that follows
+	// the common portion of the REPARSE_DATA_BUFFER element.
+	// This value is the length of the data starting at the
+	// SubstituteNameOffset field.
+	ReparseDataLength uint16
+	Reserved          uint16
+}
+
+type SymbolicLinkReparseBuffer struct {
+	// The integer that contains the offset, in bytes,
+	// of the substitute name string in the PathBuffer array,
+	// computed as an offset from byte 0 of PathBuffer. Note that
+	// this offset must be divided by 2 to get the array index.
+	SubstituteNameOffset uint16
+	// The integer that contains the length, in bytes, of the
+	// substitute name string. If this string is null-terminated,
+	// SubstituteNameLength does not include the Unicode null character.
+	SubstituteNameLength uint16
+	// PrintNameOffset is similar to SubstituteNameOffset.
+	PrintNameOffset uint16
+	// PrintNameLength is similar to SubstituteNameLength.
+	PrintNameLength uint16
+	// Flags specifies whether the substitute name is a full path name or
+	// a path name relative to the directory containing the symbolic link.
+	Flags      uint32
+	PathBuffer [1]uint16
+}
+
+// Path returns path stored in rb.
+func (rb *SymbolicLinkReparseBuffer) Path() string {
+	n1 := rb.SubstituteNameOffset / 2
+	n2 := (rb.SubstituteNameOffset + rb.SubstituteNameLength) / 2
+	return syscall.UTF16ToString((*[0xffff]uint16)(unsafe.Pointer(&rb.PathBuffer[0]))[n1:n2:n2])
+}
+
+type MountPointReparseBuffer struct {
+	// The integer that contains the offset, in bytes,
+	// of the substitute name string in the PathBuffer array,
+	// computed as an offset from byte 0 of PathBuffer. Note that
+	// this offset must be divided by 2 to get the array index.
+	SubstituteNameOffset uint16
+	// The integer that contains the length, in bytes, of the
+	// substitute name string. If this string is null-terminated,
+	// SubstituteNameLength does not include the Unicode null character.
+	SubstituteNameLength uint16
+	// PrintNameOffset is similar to SubstituteNameOffset.
+	PrintNameOffset uint16
+	// PrintNameLength is similar to SubstituteNameLength.
+	PrintNameLength uint16
+	PathBuffer      [1]uint16
+}
+
+// Path returns path stored in rb.
+func (rb *MountPointReparseBuffer) Path() string {
+	n1 := rb.SubstituteNameOffset / 2
+	n2 := (rb.SubstituteNameOffset + rb.SubstituteNameLength) / 2
+	return syscall.UTF16ToString((*[0xffff]uint16)(unsafe.Pointer(&rb.PathBuffer[0]))[n1:n2:n2])
+}