At Wed, 11 Jun 2014 10:53:35 +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 <lian...@ucweb.com>
> ---
> lib/logger.c | 26 ++++++++++++++++++++------
> 1 file changed, 20 insertions(+), 6 deletions(-)
Looks good to me.
Reviewed-by: Hitoshi Mitake <mitake.hito...@lab.ntt.co.jp>
Thanks,
Hitoshi
>
> diff --git a/lib/logger.c b/lib/logger.c
> index 6829f45..3815ee4 100644
> --- a/lib/logger.c
> +++ b/lib/logger.c
> @@ -711,13 +711,27 @@ int log_init(const char *program_name, enum
> log_dst_type type, int level,
>
> void log_close(void)
> {
> - if (la) {
> - la->active = false;
> - waitpid(logger_pid, NULL, 0);
> + pid_t pid;
> +
> + if (!la)
> + return;
>
> - syslog(LOG_WARNING, "logger pid %d stopped\n", logger_pid);
> - closelog();
> - free_logarea();
> + while (true) {
> + la->active = false;
> + pid = waitpid(logger_pid, NULL, WNOHANG);
> + if (pid == 0) {
> + usleep(100000);
> + continue;
> + } else if (pid > 0) {
> + syslog(LOG_WARNING, "logger pid %d stopped\n",
> + logger_pid);
> + closelog();
> + free_logarea();
> + break;
> + } else {
> + syslog(LOG_ERR, "waitpid() failure\n");
> + exit(1);
> + }
> }
> }
>
> --
> 1.8.3.2
>
>
> --
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