[sheepdog] [PATCH v2] lib/logger: nonblocking waitpid to avoid sheep process cannot exit

[Liu Yuan]

On Wed, Jun 11, 2014 at 10:53:35AM +0800, Ruoyu wrote:
> Sometimes sheep process cannot exit as we expected. I think the
> point might be the sequential problem by using waitpid, the
> system call waiting for process to change state.
> 
> Current log_close function calling waitpid as a void method. It
> will block the main process. Suppose this situation:
> 
> Father: --> active=false --------------------------------> waitpid
> Child: -------------> active=true --> while(active) do sth. -->
> 
> The log process will loop forever so that the main process cannot
> exit.
> 
> Therefore, it is better to retrieve the return value and pass the
> nonblocking flag WNOHANG to it. Moreover, reset share memory flag
> before each time calling waitpid.
> 
> Signed-off-by: Ruoyu <liangry at ucweb.com>
> ---

Applied thanks

Yuan