// Public Domain Source: http://win32.mvps.org/ntfs/lnw.cpp
// to compile for ANSI:
// cl lnw.cpp
// to compile for Unicode:
// cl -DUNICODE lnw.cpp
// make sure the C headers see the same Unicode mode as the Windows headers
#if defined( UNICODE ) && ! defined( _UNICODE )
#define _UNICODE
#endif
#if defined( _UNICODE ) && ! defined( UNICODE )
#define UNICODE
#endif
#include <windows.h>
#include <stdio.h>
#include <tchar.h>
#include <string.h>
#pragma hdrstop
#pragma comment( lib, "advapi32.lib" )
extern "C" {
typedef BOOL (__stdcall *chl_t)( LPCTSTR toFile, LPCTSTR fromFile, LPSECURITY_ATTRIBUTES sa );
}
extern "C" {
int create_hard_link ( TCHAR* oldpath, TCHAR* newpath );
}
// these must always be ANSI!
#ifdef UNICODE
#define CREATEHARDLINK "CreateHardLinkW"
#else
#define CREATEHARDLINK "CreateHardLinkA"
#endif
#define err doerr( _T( __FILE__ ), __LINE__ )
void doerr( const TCHAR *file, int line )
{
DWORD e;
e = GetLastError();
if ( e == 0 )
return;
_tprintf( _T( "%s(%d): gle = %lu\n" ), file, line, e );
exit( 2 );
}
void enableprivs()
{
HANDLE hToken;
byte buf[sizeof TOKEN_PRIVILEGES * 2];
TOKEN_PRIVILEGES & tkp = *( (TOKEN_PRIVILEGES *) buf );
if ( ! OpenProcessToken( GetCurrentProcess(),
TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hToken ) )
err;
// enable SeBackupPrivilege, SeRestorePrivilege
if ( !LookupPrivilegeValue( NULL, SE_BACKUP_NAME, &tkp.Privileges[0].Luid ) )
err;
if ( !LookupPrivilegeValue( NULL, SE_RESTORE_NAME, &tkp.Privileges[1].Luid ) )
err;
tkp.PrivilegeCount = 2;
tkp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
tkp.Privileges[1].Attributes = SE_PRIVILEGE_ENABLED;
if ( ! AdjustTokenPrivileges( hToken, FALSE, &tkp, sizeof tkp, NULL, NULL ) )
err;
}
#define offsetof(t,m) ((size_t) &(((t *) 0)->m))
void CreateHardLinkNt4( const TCHAR *fromFile, const TCHAR *toFile )
{
HANDLE fh;
static TCHAR buf1[MAX_PATH];
TCHAR *p;
void *ctx = NULL;
WIN32_STREAM_ID wsi;
static wchar_t buf2[MAX_PATH * 2];
DWORD numwritten;
enableprivs(); // in case we aren't admin
fh = CreateFile( toFile, 0, 0, 0, OPEN_EXISTING, 0, 0 );
if ( fh != INVALID_HANDLE_VALUE )
{
CloseHandle( fh );
_tprintf( _T( "%s already exists.\n" ), toFile );
SetLastError( ERROR_ALREADY_EXISTS );
return;
}
fh = CreateFile( fromFile, GENERIC_WRITE, 0, NULL, OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_POSIX_SEMANTICS, NULL );
if ( fh == INVALID_HANDLE_VALUE )
err;
GetFullPathName( toFile, MAX_PATH, &buf1[0], &p );
wsi.dwStreamId = BACKUP_LINK;
wsi.dwStreamAttributes = 0;
wsi.dwStreamNameSize = 0;
#ifndef UNICODE
MultiByteToWideChar( CP_ACP, 0, buf1, strlen( buf1 ) + 1, buf2, MAX_PATH );
#else
_tcscpy( buf2, buf1 );
#endif
wsi.Size.QuadPart = ( wcslen( buf2 ) + 1 ) * sizeof( wchar_t );
if ( ! BackupWrite( fh, (byte *) &wsi, offsetof( WIN32_STREAM_ID, cStreamName ), &numwritten, FALSE, FALSE, &ctx ) )
err;
if ( numwritten != offsetof( WIN32_STREAM_ID, cStreamName ) )
err;
if ( ! BackupWrite( fh, (byte *) buf2, wsi.Size.LowPart, &numwritten, FALSE, FALSE, &ctx ) )
err;
if ( numwritten != wsi.Size.LowPart )
err;
// make NT release the context
BackupWrite( fh, (byte *) &buf1[0], 0, &numwritten, TRUE, FALSE, &ctx );
CloseHandle( fh );
}
int CreateHardLinkNt5( const TCHAR *fromFile, const TCHAR *toFile )
{
chl_t chl; // pointer to CreateHardLink()
int tryOldMethod = 1; // assume we are not on NT5
// first, try the easy (NT5) way
HMODULE hmk32 = LoadLibrary( _T( "kernel32.dll" ) );
if ( hmk32 > (HMODULE) 32 )
{
chl = (chl_t) GetProcAddress( hmk32, CREATEHARDLINK );
if ( chl != NULL ) // seems to be NT5 or so
{
// we have found the API, no need for clumsy stuff
tryOldMethod = 0;
if ( ! chl( toFile, fromFile, NULL ) ) {
_tprintf( _T( "CreateHardLink( \"%s\", \"%s\" ) failed with error %lu.\n" ),
toFile, fromFile, GetLastError() );
tryOldMethod = -1;
}
}
FreeLibrary( hmk32 );
}
return tryOldMethod;
}
int create_hard_link ( TCHAR* oldpath, TCHAR* newpath ) {
int rv;
rv = CreateHardLinkNt5( oldpath, newpath );
if (rv == 1) {
CreateHardLinkNt4( oldpath, newpath );
rv = ( (GetFileAttributes(newpath) != (DWORD) -1) ? 0 : 1);
}
return rv;
}
/*
#ifdef UNICODE
int wmain( int argc, TCHAR *argv[] )
#else
int main( int argc, TCHAR *argv[] )
#endif
{
if ( argc != 3 )
{
_tprintf( _T( "usage: lnw {file} {new_link_name}\n" ) );
return 1;
}
if ( CreateHardLinkNt5( argv[1], argv[2] ) )
CreateHardLinkNt4( argv[1], argv[2] );
return 0;
}
*/