Re: msvcrt: Don't hold FILE critical section in some functions

[Piotr Caban]

On 11/15/11 16:34, Alexandre Julliard wrote:
> Piotr Caban  writes:
> > @@ -3117,25 +3098,20 @@ int CDECL MSVCRT_fputc(int c, MSVCRT_FILE* file)
> >    */
> >   int CDECL MSVCRT__flsbuf(int c, MSVCRT_FILE* file)
> >   {
> > - MSVCRT__lock_file(file);
> > -
> > /* Flush output buffer */
> > if(file->_bufsiz == 0&&  !(file->_flag&  MSVCRT__IONBF)) {
> >     msvcrt_alloc_buffer(file);
> > }
> > if(!(file->_flag&  MSVCRT__IOWRT)) {
> > -
> >    if(file->_flag&  MSVCRT__IORW) {
> > -
> >    if(file->_flag&  MSVCRT__IORW)
> >         file->_flag |= MSVCRT__IOWRT;
> > -
> >    } else {
> > -
> >        MSVCRT__unlock_file(file);
> > -
> >    else
>
> That doesn't look safe.

This function is not safe under Windows 7. I was testing it with 
following program:

static DWORD WINAPI block_stdin(void *arg)
{
    _lock_file(stdout);
    return 0;
}

int main( )
{
    DWORD thread_id;

CreateThread(NULL, 0, block_stdin, NULL, 0, &thread_id);
    Sleep(500);
    _flsbuf(32, stdout);
    return 0;
}

It terminates in Windows 7. It never ends with Wine both with and 
without my patch (because of locks in fputc and fwrite).