52a46e5c5d
improves on sigsegv handling git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1239 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
159 lines
4.1 KiB
Prolog
159 lines
4.1 KiB
Prolog
/*************************************************************************
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* *
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* YAP Prolog *
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* *
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* Yap Prolog was developed at NCCUP - Universidade do Porto *
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* *
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* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
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* *
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**************************************************************************
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* *
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* File: signals.pl *
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* Last rev: *
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* mods: *
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* comments: signal handling in YAP *
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* *
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*************************************************************************/
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:- meta_predicate on_signal(+,?,:), alarm(+,:,-).
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'$creep'(G) :-
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% get the first signal from the mask
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'$first_signal'(Sig), !,
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% process it
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'$do_signal'(Sig, G).
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'$creep'([M|G]) :-
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% noise, just go on with our life.
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'$execute'(M:G).
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'$do_signal'(sig_wake_up, G) :-
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'$awoken_goals'(LG),
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% if more signals alive, set creep flag
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'$continue_signals',
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'$wake_up_goal'(G, LG).
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'$do_signal'(sig_creep, [M|G]) :-
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( '$access_yap_flags'(10,0) ->
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% we're not allowed to creep for now,
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% maybe we're inside builtin.
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'$late_creep',
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'$execute'(M:G)
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;
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'$start_creep'([M|G])
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).
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'$do_signal'(sig_delay_creep, [M|G]) :-
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'$execute'(M:G),
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'$creep'.
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'$do_signal'(sig_iti, G) :-
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'$thread_gfetch'(Goal),
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% if more signals alive, set creep flag
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'$continue_signals',
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'$current_module'(M0),
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'$execute0'(G,M0).
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'$do_signal'(sig_trace, G) :-
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'$continue_signals',
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trace.
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'$do_signal'(sig_debug, G) :-
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'$continue_signals',
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'$current_module'(M0),
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debug,
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'$execute0'(G,M0).
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'$do_signal'(sig_break, G) :-
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'$continue_signals',
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'$current_module'(M0),
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break,
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'$execute0'(G,M0).
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'$do_signal'(sig_statistics, G) :-
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'$continue_signals',
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'$current_module'(M0),
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statistics,
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'$execute0'(G,M0).
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'$do_signal'(sig_stack_dump, G) :-
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'$continue_signals',
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'$current_module'(M0),
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'$stack_dump',
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'$execute0'(G,M0).
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% Unix signals
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'$do_signal'(sig_alarm, G) :-
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'$signal_handler'(sig_alarm, G).
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'$do_signal'(sig_hup, G) :-
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'$signal_handler'(sig_hup, G).
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'$do_signal'(sig_usr1, G) :-
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'$signal_handler'(sig_usr1, G).
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'$do_signal'(sig_usr2, G) :-
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'$signal_handler'(sig_usr2, G).
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'$signal_handler'(Sig, [M|G]) :-
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'$signal_do'(Sig, Goal),
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% if more signals alive, set creep flag
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'$continue_signals',
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'$current_module'(M0),
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'$execute0'((Goal,M:G),M0).
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% notice that the last signal to be processed must always be creep
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'$start_creep'([_|'$cut_by'(CP)]) :- !,
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'$cut_by'(CP),
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'$creep'.
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'$start_creep'([_|true]) :- !,
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'$creep'.
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'$start_creep'([Mod|G]) :-
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'$hidden_predicate'(G,Mod), !,
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'$creep',
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'$execute_nonstop'(G,Mod).
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'$start_creep'([Mod|G]) :-
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'$do_not_creep',
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CP is '$last_choice_pt',
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'$do_spy'(G, Mod, CP, yes).
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'$signal_do'(Sig, Goal) :-
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recorded('$signal_handler', action(Sig,Goal), _), !.
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'$signal_do'(Sig, Goal) :-
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'$signal_def'(Sig, Goal).
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% reconsult init files.
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'$signal_def'(sig_hup, (( exists('~/.yaprc') -> [-'~/.yaprc'] ; true ),
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( exists('~/.prologrc') -> [-'~/.prologrc'] ; true ),
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( exists('~/prolog.ini') -> [-'~/prolog.ini'] ; true ))).
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% die on signal default.
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'$signal_def'(sig_usr1, (print_message(error, 'Received user signal 1'),halt)).
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'$signal_def'(sig_usr2, (print_message(error, 'Received user signal 2'),halt)).
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% ignore sig_alarm by default
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'$signal_def'(sig_alarm, true).
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on_signal(Signal,OldAction,default) :-
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'$reset_signal'(Signal, OldAction).
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on_signal(Signal,OldAction,Action) :-
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var(Action), !,
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'$check_signal'(OldAction),
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Action = OldAction.
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on_signal(Signal,OldAction,Action) :-
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'$reset_signal'(Signal, OldAction),
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'$current_module'(M),
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recordz('$signal_handler', action(Signal,M:Action), _).
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'$reset_signal'(Signal, OldAction) :-
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recorded('$signal_handler', action(Signal,OldAction), Ref), !,
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erase(Ref).
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'$reset_signal'(_, default).
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'$check_signal'(Signal, OldAction) :-
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recorded('$signal_handler', action(Signal,OldAction), _), !.
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'$reset_signal'(_, default).
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alarm(Interval, Goal, Left) :-
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on_signal(sig_alarm, _, Goal),
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'$alarm'(Interval, Left).
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raise_exception(Ball) :- throw(Ball).
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on_exception(Pat, G, H) :- catch(G, Pat, H).
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read_sig :-
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recorded('$signal_handler',X,_),
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writeq(X),nl,
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fail.
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read_sig.
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