static bool GetREPARSE_DATA_BUFFER(const string& Object, REPARSE_DATA_BUFFER* rdb)
{
const auto FileAttr = os::fs::get_file_attributes(Object);
if (FileAttr == INVALID_FILE_ATTRIBUTES || !(FileAttr & FILE_ATTRIBUTE_REPARSE_POINT))
return false;
const os::fs::file fObject(Object, 0, 0, nullptr, OPEN_EXISTING, FILE_FLAG_OPEN_REPARSE_POINT);
if (!fObject)
return false;
DWORD dwBytesReturned;
return fObject.IoControl(FSCTL_GET_REPARSE_POINT, nullptr, 0, rdb, MAXIMUM_REPARSE_DATA_BUFFER_SIZE, &dwBytesReturned) && IsReparseTagValid(rdb->ReparseTag);
}
bool DeleteReparsePoint(const string& Object)
{
block_ptr<REPARSE_DATA_BUFFER> rdb(MAXIMUM_REPARSE_DATA_BUFFER_SIZE);
if (!GetREPARSE_DATA_BUFFER(Object, rdb.get()))
return false;
const os::fs::file fObject(Object, GetDesiredAccessForReparsePointChange(), 0, nullptr, OPEN_EXISTING, FILE_FLAG_OPEN_REPARSE_POINT);
if (!fObject)
return false;
DWORD dwBytes;
REPARSE_GUID_DATA_BUFFER rgdb{rdb->ReparseTag};
return fObject.IoControl(FSCTL_DELETE_REPARSE_POINT,&rgdb,REPARSE_GUID_DATA_BUFFER_HEADER_SIZE,nullptr,0,&dwBytes);
}
static bool SetREPARSE_DATA_BUFFER(const string& Object, REPARSE_DATA_BUFFER* rdb)
{
if (!IsReparseTagValid(rdb->ReparseTag))
return false;
SCOPED_ACTION(os::security::privilege){ SE_CREATE_SYMBOLIC_LINK_NAME };
const auto Attributes = os::fs::get_file_attributes(Object);
if(Attributes&FILE_ATTRIBUTE_READONLY)
{
os::fs::set_file_attributes(Object, Attributes&~FILE_ATTRIBUTE_READONLY);
}
SCOPE_EXIT
{
if (Attributes&FILE_ATTRIBUTE_READONLY)
os::fs::set_file_attributes(Object, Attributes);
};
const auto& SetBuffer = [&](bool ForceElevation)
{
const os::fs::file fObject(Object, GetDesiredAccessForReparsePointChange(), 0, nullptr, OPEN_EXISTING, FILE_FLAG_OPEN_REPARSE_POINT, nullptr, ForceElevation);
DWORD dwBytesReturned;
return fObject && fObject.IoControl(FSCTL_SET_REPARSE_POINT, rdb, rdb->ReparseDataLength + REPARSE_DATA_BUFFER_HEADER_SIZE, nullptr, 0, &dwBytesReturned);
};
if (SetBuffer(false))
return true;
if (ElevationRequired(ELEVATION_MODIFY_REQUEST))
{
// Open() succeeded, but IoControl() failed. We can't handle this automatically :(
return SetBuffer(true);
}
return false;
}