The error handling in cgroup_event_listener.c did not correctly deal
with either an error opening either <control_file> or
cgroup.event_control. Due to an uninitialized variable the program
exit code was undefined if either of these opens failed.
This patch simplifies and corrects cgroup_event_listener.c error
1. using err*() rather than printf(),exit()
2. depending on process exit to close open files
With this patch failures always return non-zero error.
Signed-off-by: Greg Thelen <email@example.com>
Acked-by: Li Zefan <firstname.lastname@example.org>
Signed-off-by: Tejun Heo <email@example.com>