1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
|
// **************************************************************************
// * This file is part of the FreeFileSync project. It is distributed under *
// * GNU General Public License: http://www.gnu.org/licenses/gpl.html *
// * Copyright (C) 2008-2011 ZenJu (zhnmju123 AT gmx.de) *
// **************************************************************************
//
#ifndef SYMLINK_WIN_H_INCLUDED
#define SYMLINK_WIN_H_INCLUDED
#include "loki/ScopeGuard.h"
#include <boost/scoped_array.hpp>
#include "system_func.h"
#include <wx/intl.h>
#include "string_conv.h"
#include "file_error.h"
#ifdef FFS_WIN
#include <wx/msw/wrapwin.h> //includes "windows.h"
#include "WinIoCtl.h"
#include "privilege.h"
#include "long_path_prefix.h"
#elif defined FFS_LINUX
#include <unistd.h>
#endif
#ifdef _MSC_VER //I don't have Windows Driver Kit at hands right now, so unfortunately we need to redefine this structures and cross fingers...
typedef struct _REPARSE_DATA_BUFFER
{
ULONG ReparseTag;
USHORT ReparseDataLength;
USHORT Reserved;
union
{
struct
{
USHORT SubstituteNameOffset;
USHORT SubstituteNameLength;
USHORT PrintNameOffset;
USHORT PrintNameLength;
ULONG Flags;
WCHAR PathBuffer[1];
} SymbolicLinkReparseBuffer;
struct
{
USHORT SubstituteNameOffset;
USHORT SubstituteNameLength;
USHORT PrintNameOffset;
USHORT PrintNameLength;
WCHAR PathBuffer[1];
} MountPointReparseBuffer;
struct
{
UCHAR DataBuffer[1];
} GenericReparseBuffer;
};
} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;
#define REPARSE_DATA_BUFFER_HEADER_SIZE FIELD_OFFSET(REPARSE_DATA_BUFFER, GenericReparseBuffer)
#endif
namespace
{
//retrieve raw target data of symlink or junction
Zstring getSymlinkRawTargetString(const Zstring& linkPath) //throw (FileError)
{
using ffs3::zToWx;
using ffs3::FileError;
#ifdef FFS_WIN
//FSCTL_GET_REPARSE_POINT: http://msdn.microsoft.com/en-us/library/aa364571(VS.85).aspx
try //reading certain symlinks requires admin rights! This shall not cause an error in user mode!
{
//allow access to certain symbolic links/junctions
ffs3::Privileges::getInstance().ensureActive(SE_BACKUP_NAME); //throw FileError()
}
catch (...) {}
const HANDLE hLink = ::CreateFile(ffs3::applyLongPathPrefix(linkPath).c_str(),
GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
NULL,
OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT,
NULL);
if (hLink == INVALID_HANDLE_VALUE)
{
wxString errorMessage = wxString(_("Error resolving symbolic link:")) + wxT("\n\"") + ffs3::zToWx(linkPath) + wxT("\"");
throw FileError(errorMessage + wxT("\n\n") + ffs3::getLastErrorFormatted());
}
Loki::ScopeGuard dummy = Loki::MakeGuard(::CloseHandle, hLink);
(void)dummy; //silence warning "unused variable"
//respect alignment issues...
const size_t bufferSize = REPARSE_DATA_BUFFER_HEADER_SIZE + MAXIMUM_REPARSE_DATA_BUFFER_SIZE;
boost::scoped_array<char> buffer(new char[bufferSize]);
DWORD bytesReturned; //dummy value required by FSCTL_GET_REPARSE_POINT!
if (!::DeviceIoControl(hLink, //__in HANDLE hDevice,
FSCTL_GET_REPARSE_POINT, //__in DWORD dwIoControlCode,
NULL, //__in_opt LPVOID lpInBuffer,
0, //__in DWORD nInBufferSize,
buffer.get(), //__out_opt LPVOID lpOutBuffer,
bufferSize, //__in DWORD nOutBufferSize,
&bytesReturned, //__out_opt LPDWORD lpBytesReturned,
NULL)) //__inout_opt LPOVERLAPPED lpOverlapped
{
wxString errorMessage = wxString(_("Error resolving symbolic link:")) + wxT("\n\"") + ffs3::zToWx(linkPath) + wxT("\"");
throw FileError(errorMessage + wxT("\n\n") + ffs3::getLastErrorFormatted());
}
REPARSE_DATA_BUFFER& reparseData = *reinterpret_cast<REPARSE_DATA_BUFFER*>(buffer.get()); //REPARSE_DATA_BUFFER needs to be artificially enlarged!
Zstring output;
if (reparseData.ReparseTag == IO_REPARSE_TAG_SYMLINK)
{
output = Zstring(reparseData.SymbolicLinkReparseBuffer.PathBuffer + reparseData.SymbolicLinkReparseBuffer.SubstituteNameOffset / sizeof(WCHAR),
reparseData.SymbolicLinkReparseBuffer.SubstituteNameLength / sizeof(WCHAR));
}
else if (reparseData.ReparseTag == IO_REPARSE_TAG_MOUNT_POINT)
{
output = Zstring(reparseData.MountPointReparseBuffer.PathBuffer + reparseData.MountPointReparseBuffer.SubstituteNameOffset / sizeof(WCHAR),
reparseData.MountPointReparseBuffer.SubstituteNameLength / sizeof(WCHAR));
}
else
{
wxString errorMessage = wxString(_("Error resolving symbolic link:")) + wxT("\n\"") + ffs3::zToWx(linkPath) + wxT("\"");
throw FileError(errorMessage + wxT("\n\n") + wxT("Not a symbolic link or junction!"));
}
//absolute symlinks and junctions technically start with \??\ while relative ones do not
if (output.StartsWith(Zstr("\\??\\")))
output = Zstring(output.c_str() + 4, output.length() - 4);
return output;
#elif defined FFS_LINUX
const int BUFFER_SIZE = 10000;
char buffer[BUFFER_SIZE];
const int bytesWritten = ::readlink(linkPath.c_str(), buffer, BUFFER_SIZE);
if (bytesWritten < 0 || bytesWritten >= BUFFER_SIZE)
{
wxString errorMessage = wxString(_("Error resolving symbolic link:")) + wxT("\n\"") + zToWx(linkPath) + wxT("\"");
if (bytesWritten < 0) errorMessage += wxString(wxT("\n\n")) + ffs3::getLastErrorFormatted();
throw FileError(errorMessage);
}
buffer[bytesWritten] = 0; //set null-terminating char
return buffer;
#endif
}
}
#endif // SYMLINK_WIN_H_INCLUDED
|
