Messages in this thread | | | From | Ray Lee <> | Date | Mon, 8 Mar 2010 16:45:38 -0800 | Subject | Re: [PATCH] exit: PR_SET_ANCHOR for marking processes as reapers for child processes |
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On Fri, Mar 5, 2010 at 4:24 PM, Lennart Poettering <mzxreary@0pointer.de> wrote: > On Fri, 05.03.10 11:18, Roland McGrath (roland@redhat.com) wrote: > >> >> > Oh, no. Actually getting the SIGCHILD is the needed feature here. A >> > process who sets the ANCHOR flag is surely expected to handle these >> > signals. It's all about a user "init-like" process" that can do >> > similar things for a logged-in user what /sbin/init can to for the >> > system. So, it's all about 1.), and 3.) is a nice side-effect, but not >> > the motivation to do this. >> >> Please explain this more explicitly. What the actual init does with >> miscellaneous reparented processes is just reap them and ignore their >> status. What do you intend an "anchor" process to do other than that? > > It could use the grandchildren's SIGCHLDs for various task management > issues: i.e. watching double-forking daemons, catch SIGSEGVS so that you > can crosslink that service state to systems like abrt. Or even just that > you can implement a safe restarting logic: i.e. so that we can easily > wait that a process and its children are fully dead before we restart > the service.
The kernel already offers system-wide process exit notification via taskstats (a netlink interface), though unfortunately I believe it's optional. It's pretty easy to use (as these things go, anyway -- I was able to hack up an arbitrary process exit watcher in about a half hour based on Documentation/accounting/getdelays.c).
Would this existing mechanism cover what you need? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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