Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: [PATCH v6] Added PR_SET_PROCTITLE_AREA option for prctl() | Date | Tue, 8 Dec 2009 15:53:21 +0900 (JST) |
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> > > > * KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote: > > > > > > The feature looks useful, but the choice of a prctl as an API is strange > > > > - it limits us to the current task only - while the ability to set > > > > arguments for another task looks a more generic (and potentially more > > > > useful) solution. > > > > > > No. It's impossible. > > > /proc/{pid}/cmdline read user process's memory. iow, this prctl() don't > > > receive string, it receive virtual address itself. [...] > > > > it's not 'impossible' at all, you yourself mention ptrace: > > Ah yes, 'impossible' was wrong word. but it doesn't works intentionally. > > 1. setproctitle() unaware application continue to see argv[0] directly. > it makes some inconsistent behavior. > 2. proc title (i.e. string) injection need to map new page as process title area. > implicit mapping increasing makes new trouble > - mihgt cause to exceed max_map_count awhile after. > - might cause leak proc title area (who know when it should be freed?) > > I think reasonable way is 1. send signal (or use another inter process > communication way) to target process 2. target process change own proc title > themself. > > Plus, I haven't seen the use-case of changin another task. iow I doubt > it's worth to change lots code.
if your mention is strongly, can you please explain your expected use case?
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