424 lines
13 KiB
C++
424 lines
13 KiB
C++
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// Copyright 2015 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http ://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "stdafx.h"
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#include "ReparsePoint.h"
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#include "ScopedHandle.h"
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#include "typed_buffer.h"
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#include <string>
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#include <vector>
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// Taken from ntifs.h
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#define SYMLINK_FLAG_RELATIVE 1
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typedef struct _REPARSE_DATA_BUFFER {
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ULONG ReparseTag;
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USHORT ReparseDataLength;
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USHORT Reserved;
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union {
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struct {
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USHORT SubstituteNameOffset;
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USHORT SubstituteNameLength;
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USHORT PrintNameOffset;
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USHORT PrintNameLength;
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ULONG Flags;
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WCHAR PathBuffer[1];
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} SymbolicLinkReparseBuffer;
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struct {
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USHORT SubstituteNameOffset;
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USHORT SubstituteNameLength;
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USHORT PrintNameOffset;
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USHORT PrintNameLength;
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WCHAR PathBuffer[1];
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} MountPointReparseBuffer;
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struct {
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UCHAR DataBuffer[1];
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} GenericReparseBuffer;
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} DUMMYUNIONNAME;
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} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;
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#define REPARSE_DATA_BUFFER_HEADER_LENGTH FIELD_OFFSET(REPARSE_DATA_BUFFER, GenericReparseBuffer.DataBuffer)
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#define IO_REPARSE_TAG_MOUNT_POINT (0xA0000003L) // winnt
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#define IO_REPARSE_TAG_HSM (0xC0000004L) // winnt
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#define IO_REPARSE_TAG_DRIVE_EXTENDER (0x80000005L)
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#define IO_REPARSE_TAG_HSM2 (0x80000006L) // winnt
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#define IO_REPARSE_TAG_SIS (0x80000007L) // winnt
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#define IO_REPARSE_TAG_WIM (0x80000008L) // winnt
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#define IO_REPARSE_TAG_CSV (0x80000009L) // winnt
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#define IO_REPARSE_TAG_DFS (0x8000000AL) // winnt
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#define IO_REPARSE_TAG_FILTER_MANAGER (0x8000000BL)
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#define IO_REPARSE_TAG_SYMLINK (0xA000000CL) // winnt
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#define IO_REPARSE_TAG_IIS_CACHE (0xA0000010L)
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#define IO_REPARSE_TAG_DFSR (0x80000012L) // winnt
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#define IO_REPARSE_TAG_DEDUP (0x80000013L) // winnt
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#define IO_REPARSE_TAG_APPXSTRM (0xC0000014L)
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#define IO_REPARSE_TAG_NFS (0x80000014L) // winnt
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#define IO_REPARSE_TAG_FILE_PLACEHOLDER (0x80000015L) // winnt
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#define IO_REPARSE_TAG_DFM (0x80000016L)
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#define IO_REPARSE_TAG_WOF (0x80000017L) // winnt
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static int g_last_error = 0;
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int ReparsePoint::GetLastError()
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{
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return g_last_error;
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}
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ScopedHandle OpenReparsePoint(const std::wstring& path, bool writable)
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{
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HANDLE h = CreateFile(path.c_str(),
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GENERIC_READ | (writable ? GENERIC_WRITE : 0),
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0,
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0,
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OPEN_EXISTING,
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FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT,
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0);
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if (h == INVALID_HANDLE_VALUE)
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{
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g_last_error = GetLastError();
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char buffer[50];
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sprintf_s(buffer, "%d", g_last_error);
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MessageBoxA(NULL, buffer, "OpenReparsePoint() Failure", MB_OK);
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}
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return ScopedHandle(h, false);
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}
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static bool SetReparsePoint(const ScopedHandle& handle, typed_buffer_ptr<REPARSE_DATA_BUFFER>& reparse_buffer)
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{
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DWORD cb;
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if (!handle.IsValid()) {
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return false;
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}
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bool ret = DeviceIoControl(handle, FSCTL_SET_REPARSE_POINT,
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reparse_buffer, reparse_buffer.size(), nullptr, 0, &cb, nullptr) == TRUE;
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if (!ret)
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{
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g_last_error = GetLastError();
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}
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return ret;
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}
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static bool DeleteReparsePoint(const ScopedHandle& handle, PREPARSE_GUID_DATA_BUFFER reparse_buffer)
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{
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DWORD cb;
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if (!handle.IsValid()) {
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return false;
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}
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bool ret = DeviceIoControl(handle,
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FSCTL_DELETE_REPARSE_POINT,
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reparse_buffer,
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REPARSE_GUID_DATA_BUFFER_HEADER_SIZE,
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nullptr,
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0,
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&cb,
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0) == TRUE;
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if (!ret)
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{
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g_last_error = GetLastError();
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char buffer[50];
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sprintf_s(buffer, "%d", g_last_error);
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MessageBoxA(NULL, buffer, "DeleteReparsePoint() Failure", MB_OK);
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}
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return ret;
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}
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typed_buffer_ptr<REPARSE_DATA_BUFFER> BuildMountPoint(const std::wstring& target, const std::wstring& printname)
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{
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const size_t target_byte_size = target.size() * 2;
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const size_t printname_byte_size = printname.size() * 2;
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const size_t path_buffer_size = target_byte_size + printname_byte_size + 8 + 4;
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const size_t total_size = path_buffer_size + REPARSE_DATA_BUFFER_HEADER_LENGTH;
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typed_buffer_ptr<REPARSE_DATA_BUFFER> buffer(total_size);
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buffer->ReparseTag = IO_REPARSE_TAG_MOUNT_POINT;
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buffer->ReparseDataLength = static_cast<USHORT>(path_buffer_size);
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buffer->Reserved = 0;
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buffer->MountPointReparseBuffer.SubstituteNameOffset = 0;
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buffer->MountPointReparseBuffer.SubstituteNameLength = static_cast<USHORT>(target_byte_size);
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memcpy(buffer->MountPointReparseBuffer.PathBuffer, target.c_str(), target_byte_size + 2);
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buffer->MountPointReparseBuffer.PrintNameOffset = static_cast<USHORT>(target_byte_size + 2);
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buffer->MountPointReparseBuffer.PrintNameLength = static_cast<USHORT>(printname_byte_size);
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memcpy(buffer->MountPointReparseBuffer.PathBuffer + target.size() + 1, printname.c_str(), printname_byte_size + 2);
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return buffer;
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}
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typed_buffer_ptr<REPARSE_DATA_BUFFER> BuildSymlink(const std::wstring& target, const std::wstring& printname, bool relative)
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{
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const size_t target_byte_size = target.size() * 2;
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const size_t printname_byte_size = printname.size() * 2;
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const size_t path_buffer_size = target_byte_size + printname_byte_size + 12 + 4;
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const size_t total_size = path_buffer_size + REPARSE_DATA_BUFFER_HEADER_LENGTH;
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typed_buffer_ptr<REPARSE_DATA_BUFFER> buffer(total_size);
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buffer->ReparseTag = IO_REPARSE_TAG_SYMLINK;
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buffer->ReparseDataLength = static_cast<USHORT>(path_buffer_size);
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buffer->Reserved = 0;
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buffer->SymbolicLinkReparseBuffer.SubstituteNameOffset = 0;
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buffer->SymbolicLinkReparseBuffer.SubstituteNameLength = static_cast<USHORT>(target_byte_size);
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memcpy(buffer->SymbolicLinkReparseBuffer.PathBuffer, target.c_str(), target_byte_size + 2);
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buffer->SymbolicLinkReparseBuffer.PrintNameOffset = static_cast<USHORT>(target_byte_size + 2);
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buffer->SymbolicLinkReparseBuffer.PrintNameLength = static_cast<USHORT>(printname_byte_size);
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memcpy(buffer->SymbolicLinkReparseBuffer.PathBuffer + target.size() + 1, printname.c_str(), printname_byte_size + 2);
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buffer->SymbolicLinkReparseBuffer.Flags = relative ? SYMLINK_FLAG_RELATIVE : 0;
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return buffer;
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}
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static bool CreateMountPointInternal(const std::wstring& path, typed_buffer_ptr<REPARSE_DATA_BUFFER>& buffer)
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{
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ScopedHandle handle = OpenReparsePoint(path, true);
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if (!handle.IsValid())
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{
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return false;
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}
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return SetReparsePoint(handle, buffer);
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}
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static bool CreateMountPointInternal(const ScopedHandle& handle, typed_buffer_ptr<REPARSE_DATA_BUFFER>& buffer)
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{
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return SetReparsePoint(handle, buffer);
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}
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std::wstring FixupPath(std::wstring str)
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{
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if (str[0] != '\\')
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{
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return L"\\??\\" + str;
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}
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return str;
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}
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bool ReparsePoint::CreateMountPoint(const std::wstring& path, const std::wstring& target, const std::wstring& printname)
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{
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if (target.length() == 0)
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{
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return false;
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}
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return CreateMountPointInternal(path, BuildMountPoint(FixupPath(target), printname));
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}
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bool ReparsePoint::CreateSymlink(const std::wstring& path, const std::wstring& target, const std::wstring& printname, bool relative)
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{
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if (target.length() == 0)
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{
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return false;
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}
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return CreateMountPointInternal(path, BuildSymlink(!relative ? FixupPath(target) : target, printname, relative));
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}
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bool ReparsePoint::CreateSymlink(HANDLE h, const std::wstring& target, const std::wstring& printname, bool relative)
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{
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ScopedHandle handle(h, true);
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if (!handle.IsValid())
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{
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return false;
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}
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return CreateMountPointInternal(handle, BuildSymlink(!relative ? FixupPath(target) : target, printname, relative));
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}
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bool ReparsePoint::DeleteMountPoint(const std::wstring& path)
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{
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REPARSE_GUID_DATA_BUFFER reparse_buffer = { 0 };
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reparse_buffer.ReparseTag = IO_REPARSE_TAG_MOUNT_POINT;
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ScopedHandle handle = OpenReparsePoint(path, true);
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return DeleteReparsePoint(handle, &reparse_buffer);
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}
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bool ReparsePoint::CreateRawMountPoint(const std::wstring& path, DWORD reparse_tag, const std::vector<BYTE>& buffer)
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{
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typed_buffer_ptr<REPARSE_DATA_BUFFER> reparse_buffer(8 + buffer.size());
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reparse_buffer->ReparseTag = reparse_tag;
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reparse_buffer->ReparseDataLength = static_cast<USHORT>(buffer.size());
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reparse_buffer->Reserved = 0;
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memcpy(reparse_buffer->GenericReparseBuffer.DataBuffer, &buffer[0], buffer.size());
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return CreateMountPointInternal(path, reparse_buffer);
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}
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static typed_buffer_ptr<REPARSE_DATA_BUFFER> GetReparsePointData(ScopedHandle handle)
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{
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typed_buffer_ptr<REPARSE_DATA_BUFFER> buf(MAXIMUM_REPARSE_DATA_BUFFER_SIZE);
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DWORD dwBytesReturned;
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if (!DeviceIoControl(handle,
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FSCTL_GET_REPARSE_POINT,
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NULL,
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0,
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(LPVOID)buf,
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buf.size(),
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&dwBytesReturned,
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0)
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)
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{
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g_last_error = GetLastError();
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buf.reset(0);
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}
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return buf;
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}
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std::wstring ReparsePoint::GetMountPointTarget(const std::wstring& path)
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{
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ScopedHandle handle = OpenReparsePoint(path, false);
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if (!handle.IsValid())
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{
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return L"";
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}
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typed_buffer_ptr<REPARSE_DATA_BUFFER> buf = GetReparsePointData(handle);
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if (buf.size() == 0)
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{
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return L"";
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}
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if (buf->ReparseTag != IO_REPARSE_TAG_MOUNT_POINT)
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{
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g_last_error = ERROR_REPARSE_TAG_MISMATCH;
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return L"";
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}
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WCHAR* base = &buf->MountPointReparseBuffer.PathBuffer[buf->MountPointReparseBuffer.SubstituteNameOffset / 2];
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return std::wstring(base, base + (buf->MountPointReparseBuffer.SubstituteNameLength / 2));
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}
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bool ReparsePoint::IsReparsePoint(const std::wstring& path)
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{
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ScopedHandle handle = OpenReparsePoint(path, false);
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BY_HANDLE_FILE_INFORMATION file_info = { 0 };
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return handle.IsValid() && GetFileInformationByHandle(handle, &file_info) && file_info.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT;
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}
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static bool ReadReparsePoint(const std::wstring& path, typed_buffer_ptr<REPARSE_DATA_BUFFER>& reparse_buffer)
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{
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ScopedHandle handle = OpenReparsePoint(path, false);
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reparse_buffer.reset(4096);
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DWORD dwSize;
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bool ret = DeviceIoControl(handle, FSCTL_GET_REPARSE_POINT, nullptr, 0, reparse_buffer, reparse_buffer.size(), &dwSize, nullptr) == TRUE;
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if (!ret)
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{
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g_last_error = GetLastError();
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return false;
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}
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else
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{
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reparse_buffer.resize(dwSize);
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return true;
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}
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}
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static bool IsReparseTag(const std::wstring& path, DWORD reparse_tag)
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{
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typed_buffer_ptr<REPARSE_DATA_BUFFER> buffer;
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if (ReadReparsePoint(path, buffer))
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{
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return buffer->ReparseTag == reparse_tag;
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}
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else
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{
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return false;
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}
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}
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bool ReparsePoint::IsMountPoint(const std::wstring& path)
|
||
|
|
{
|
||
|
|
return IsReparseTag(path, IO_REPARSE_TAG_MOUNT_POINT);
|
||
|
|
}
|
||
|
|
|
||
|
|
bool ReparsePoint::IsSymlink(const std::wstring& path)
|
||
|
|
{
|
||
|
|
return IsReparseTag(path, IO_REPARSE_TAG_SYMLINK);
|
||
|
|
}
|
||
|
|
|
||
|
|
bool ReparsePoint::ReadMountPoint(const std::wstring& path, std::wstring& target, std::wstring& printname)
|
||
|
|
{
|
||
|
|
typed_buffer_ptr<REPARSE_DATA_BUFFER> buffer;
|
||
|
|
|
||
|
|
if (ReadReparsePoint(path, buffer) && buffer->ReparseTag == IO_REPARSE_TAG_MOUNT_POINT)
|
||
|
|
{
|
||
|
|
WCHAR* target_name = &buffer->MountPointReparseBuffer.PathBuffer[buffer->MountPointReparseBuffer.SubstituteNameOffset / 2];
|
||
|
|
WCHAR* display_name = &buffer->MountPointReparseBuffer.PathBuffer[buffer->MountPointReparseBuffer.PrintNameOffset / 2];
|
||
|
|
target.assign(target_name, target_name + buffer->MountPointReparseBuffer.SubstituteNameLength / 2);
|
||
|
|
printname.assign(display_name, display_name + buffer->MountPointReparseBuffer.PrintNameLength / 2);
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
bool ReparsePoint::ReadSymlink(const std::wstring& path, std::wstring& target, std::wstring& printname, unsigned int* flags)
|
||
|
|
{
|
||
|
|
typed_buffer_ptr<REPARSE_DATA_BUFFER> buffer;
|
||
|
|
|
||
|
|
if (ReadReparsePoint(path, buffer) && buffer->ReparseTag == IO_REPARSE_TAG_SYMLINK)
|
||
|
|
{
|
||
|
|
WCHAR* target_name = &buffer->SymbolicLinkReparseBuffer.PathBuffer[buffer->SymbolicLinkReparseBuffer.SubstituteNameOffset / 2];
|
||
|
|
WCHAR* display_name = &buffer->SymbolicLinkReparseBuffer.PathBuffer[buffer->SymbolicLinkReparseBuffer.PrintNameOffset / 2];
|
||
|
|
target.assign(target_name, target_name + buffer->SymbolicLinkReparseBuffer.SubstituteNameLength / 2);
|
||
|
|
printname.assign(display_name, display_name + buffer->SymbolicLinkReparseBuffer.PrintNameLength / 2);
|
||
|
|
*flags = buffer->SymbolicLinkReparseBuffer.Flags;
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
bool ReparsePoint::ReadRaw(const std::wstring& path, unsigned int* reparse_tag, std::vector<BYTE>& raw_data)
|
||
|
|
{
|
||
|
|
typed_buffer_ptr<REPARSE_DATA_BUFFER> buffer;
|
||
|
|
|
||
|
|
if (ReadReparsePoint(path, buffer))
|
||
|
|
{
|
||
|
|
*reparse_tag = buffer->ReparseTag;
|
||
|
|
raw_data.resize(buffer->ReparseDataLength);
|
||
|
|
memcpy(&raw_data[0], buffer->GenericReparseBuffer.DataBuffer, buffer->ReparseDataLength);
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
return false;
|
||
|
|
}
|