Re: dietlibc (0.31), fork and pthreads

Hello,

On Mon, March 1, 2010 14:23, Ingo Struck wrote:
> Hello again,
>
> it seems that I can explain now why your fd 0 is closed
> (compiled a debug version of diet-0.32). I am sorry to say that I do not
> know a good fix for it, because obviously the libpthread code relies on
> an internal pipe for the "manager" thread.
>
> Explanation:
>
> If you do not have any call to a pthread function before
> you pipe() / fork() the pthread library code is not initialized;
> there is no call to __thread_init, hence no call to __manager_thread_init,
> so the call to __thread_manager_close works on an uninitialized __manager_pipe
> (both entries are 0).
> So
>   close(mgr_recv_fd);
>   close(mgr_send_fd);
> in libpthread/pthread_internal.c, line 422 and 423 read
>   close(0);
>   close(0);
>
> This is why the call to fork() closes fd 0 within the child branch of fork.

mgr_recv_fd and mgr_send_fd should be initialized to -1 instead of 0.

Greetings,

Indan