Messages in this thread |  | | From | Paul Menage <> | Subject | Re: [PATCH][RFC] Pollable /proc/<pid>/ - avoid SIGCHLD/poll() races | Date | Thu, 04 Oct 2001 02:31:40 -0700 |
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>> The only real user-space solution to this is to have the SIGCHLD >> handler somehow cause the select() to return immediately > >... or implement pselect: >http://mesh.eecs.umich.edu/cgi-bin/man2html/usr/share/man/man2/select.2.gz
Agreed, althought that's not a user-space solution. Is there any fundamental reason why no-one's implemented pselect()/ppoll() for Linux yet?
> >or use sigsetjmp/siglongjmp
Yes, that would probably solve the situation in question, provided that siglongjmp() is portably safe. (A comment on LKML in the past suggested that it's not safe on cygwin, for example.)
> >Both would be portable and not special to child handling.
One advantage of the pollable /proc/<pid>, (when combined with do_notify_parent() waking tsk->exit_chldwait) is that any process can check for the exit of any other process (not just direct children) in a select()/poll() call.
Paul
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