On 08/17, Oleg Nesterov wrote: > > On 08/16, Andrew Morton wrote: > > > > From: Lennart Poettering <lennart@xxxxxxxxxxxxxx> > > > > Userspace service managers/supervisors need to track their started > > services. Many services daemonize by double-forking and get implicitely > > re-parented to PID 1. The process manager will no longer be able to > > receive the SIGCHLD signals for them. > > > > With this prctl, a service manager can mark itself as a sort of 'sub-init' > > process, able to stay as the parent process for all processes created by > > the started services. All SIGCHLD signals will be delivered to the > > service manager. > > I try to never argue with the new features. But to be honest, this > doesn't look very good to me. > > OK, a service manager M does prctl(PR_SET_CHILD_REAPER), then it forks > a service X which forks another child C and exits. Then C exits and > notifies M. > > But. How can M know that the service X should be restarted? It only > knows the pid. What if wait(WEXITED) succeeds because C in turn does > fork + exit? What M has 2 or more services? Also. I am almost sure I have already reviewed a very similar patch a long ago. Ungortunately, I can't find the previous discussion, and I can't recall why that patch was not accepted. But, I seem to remember, that patch cleared ->child_reaper on exec, I think this makes sense. And I am not sure about security. No, I do not see any problems, just I don't know. Say, should we check the creds during reparenting? I dunno. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
