int.erl

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%% ``The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved via the world wide web at http://www.erlang.org/.
%% 
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%% 
%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
%% AB. All Rights Reserved.''
%% 
%%     $Id$
%%
-module(int).

%% External exports
-export([i/1, i/2, ni/1, ni/2, n/1, nn/1, interpreted/0, file/1,
	 interpretable/1]).
-export([auto_attach/0, auto_attach/1, auto_attach/2,
	 stack_trace/0, stack_trace/1]).
-export([break/2, delete_break/2, break_in/3, del_break_in/3,
	 no_break/0, no_break/1,
	 disable_break/2, enable_break/2,
	 action_at_break/3, test_at_break/3, get_binding/2,
	 all_breaks/0, all_breaks/1]).
-export([snapshot/0, clear/0]).
-export([continue/1, continue/3]).

%% External exports only to be used by Debugger
-export([start/0, stop/0, subscribe/0]).
-export([attach/2, step/1, next/1, finish/1]).

%% External exports only to be used by an attached process
-export([attached/1, meta/2, meta/3, contents/2, functions/1]).

%% External export only to be used by error_handler
-export([eval/3]).

%%==Erlang Interpreter================================================
%%
%% int
%% ---
%% Interface module.
%%
%% i
%% -
%% Interface module to int, retained for backwards compatibility only.
%%
%% dbg_debugged
%% ------------
%% Contains the message loops for a debugged process and is the main
%% entry point from the breakpoint handler in the error_handler module
%% (via the int module).
%%
%% When a process is debugged, most code is executed in another
%% process, called the meta process. When the meta process is
%% interpreting code, the process being debugged just waits in a
%% receive loop in dbg_debugged. However the debugged process itself
%% calls any BIFs that must execute in the correct process (such as
%% link/1 and spawn_link/1), and external code which is not
%% interpreted.
%%
%% dbg_icmd, dbg_ieval
%% -------------------
%% Code for the meta process.
%%
%% dbg_iserver
%% -----------
%% Interpreter main process, keeping and distributing information
%% about interpreted modules and debugged processes.
%%
%% dbg_idb
%% -------
%% ETS wrapper, allowing transparent access to tables at a remote node.
%%
%% dbg_iload
%% ---------
%% Code for interpreting a module.
%%====================================================================
 
%%====================================================================
%% External exports
%%====================================================================

%%--------------------------------------------------------------------
%% i(AbsMods) -> {module,Mod} | error | ok
%% ni(AbsMods) -> {module,Mod} | error | ok
%%   AbsMods = AbsMod | [AbsMod]
%%     AbsMod = atom() | string()
%%     Mod = atom()
%%     Options = term() ignored
%%--------------------------------------------------------------------
i(AbsMods) -> i2(AbsMods, local).
i(AbsMods, _Options) -> i2(AbsMods, local).
ni(AbsMods) -> i2(AbsMods, distributed).
ni(AbsMods, _Options) -> i2(AbsMods, distributed).
    
i2([AbsMod|AbsMods], Dist) when is_atom(AbsMod); is_list(AbsMod) ->
    int_mod(AbsMod, Dist),
    i2(AbsMods, Dist);
i2([AbsMod], Dist) when is_atom(AbsMod); is_list(AbsMod) ->
    int_mod(AbsMod, Dist);
i2([], _Dist) ->
    ok;
i2(AbsMod, Dist) when is_atom(AbsMod); is_list(AbsMod) ->
    int_mod(AbsMod, Dist).

%%--------------------------------------------------------------------
%% n(AbsMods) -> ok
%% nn(AbsMods) -> ok
%%--------------------------------------------------------------------
n(AbsMods) -> n2(AbsMods, local).
nn(AbsMods) -> n2(AbsMods, distributed).

n2([AbsMod|AbsMods], Dist) when is_atom(AbsMod); is_list(AbsMod) ->
    del_mod(AbsMod, Dist),
    n2(AbsMods, Dist);
n2([AbsMod], Dist) when is_atom(AbsMod); is_list(AbsMod) ->
    del_mod(AbsMod, Dist);
n2([], _Dist) ->
    ok;
n2(AbsMod, Dist) when is_atom(AbsMod); is_list(AbsMod) ->
    del_mod(AbsMod, Dist).

%%--------------------------------------------------------------------
%% interpreted() -> [Mod]
%%--------------------------------------------------------------------
interpreted() ->
    dbg_iserver:safe_call(all_interpreted).

%%--------------------------------------------------------------------
%% file(Mod) -> File | {error, not_loaded}
%%   Mod = atom()
%%   File = string()
%%--------------------------------------------------------------------
file(Mod) when is_atom(Mod) ->
    dbg_iserver:safe_call({file, Mod}).

%%--------------------------------------------------------------------
%% interpretable(AbsMod) -> true | {error, Reason}
%%   AbsMod = Mod | File
%%   Reason = no_src | no_beam | no_debug_info | badarg | {app, App}
%%--------------------------------------------------------------------
interpretable(AbsMod) ->
    case check(AbsMod) of
	{ok, _Res} -> true;
	Error -> Error
    end.

%%--------------------------------------------------------------------
%% auto_attach() -> false | {Flags, Function}
%% auto_attach(false)
%% auto_attach(false|Flags, Function)
%%   Flags = Flag | [Flag]
%%     Flag = init | break | exit
%%   Function = {Mod, Func} | {Mod, Func, Args}
%% Will result in calling:
%%  spawn(Mod, Func, [Dist, Pid, Meta | Args]) (living process) or
%%  spawn(Mod, Func, [Dist, Pid, Reason, Info | Args]) (dead process)
%%--------------------------------------------------------------------
auto_attach() ->
    dbg_iserver:safe_call(get_auto_attach).

auto_attach(false) ->
    dbg_iserver:safe_cast({set_auto_attach, false}).

auto_attach([], _Function) ->
    auto_attach(false);
auto_attach(Flags, {Mod, Func}) ->
    auto_attach(Flags, {Mod, Func, []});
auto_attach(Flags, {Mod, Func, Args}) when is_atom(Mod),is_atom(Func),is_list(Args) ->
    check_flags(Flags),
    dbg_iserver:safe_cast({set_auto_attach, Flags, {Mod, Func, Args}}).

check_flags([init|Flags]) -> check_flags(Flags);
check_flags([break|Flags]) -> check_flags(Flags);
check_flags([exit|Flags]) -> check_flags(Flags);
check_flags([]) -> true.

%%--------------------------------------------------------------------
%% stack_trace() -> Flag
%% stack_trace(Flag)
%%   Flag = all | true | no_tail | false
%%--------------------------------------------------------------------
stack_trace() ->
    dbg_iserver:safe_call(get_stack_trace).

stack_trace(true) ->
    stack_trace(all);
stack_trace(Flag) ->
    check_flag(Flag),
    dbg_iserver:safe_cast({set_stack_trace, Flag}).

check_flag(all) -> true;
check_flag(no_tail) -> true;
check_flag(false) -> true.

%%--------------------------------------------------------------------
%% break(Mod, Line) -> ok | {error, break_exists}
%% delete_break(Mod, Line) -> ok
%% break_in(Mod, Func, Arity) -> ok | {error, function_not_found}
%% del_break_in(Mod, Function, Arity) -> ok | {error, function_not_found}
%% no_break()
%% no_break(Mod)
%% disable_break(Mod, Line) -> ok
%% enable_break(Mod, Line) -> ok
%% action_at_break(Mod, Line, Action) -> ok
%% test_at_break(Mod, Line, Function) -> ok
%% get_binding(Var, Bindings) -> {value, Value} | unbound
%% all_breaks() -> [Break]
%% all_breaks(Mod) -> [Break]
%%   Mod = atom()
%%   Line = integer()
%%   Func = atom() function name
%%   Arity = integer()
%%   Action = enable | disable | delete
%%   Function = {Mod, Func} must have arity 1 (Bindings)
%%   Var = atom()
%%   Bindings = Value = term()
%%   Break = {Point, Options}
%%     Point = {Mod, Line}
%%     Options = [Status, Action, null, Cond]
%%       Status = active | inactive
%%       Cond = null | Function
%%--------------------------------------------------------------------
break(Mod, Line) when is_atom(Mod), is_integer(Line) ->
    dbg_iserver:safe_call({new_break, {Mod, Line},
			   [active, enable, null, null]}).

delete_break(Mod, Line) when is_atom(Mod), is_integer(Line) ->
    dbg_iserver:safe_cast({delete_break, {Mod, Line}}).

break_in(Mod, Func, Arity) when is_atom(Mod), is_atom(Func), is_integer(Arity) ->
    case dbg_iserver:safe_call({is_interpreted, Mod, Func, Arity}) of
	{true, Clauses} ->
	    Lines = first_lines(Clauses),
	    lists:foreach(fun(Line) -> break(Mod, Line) end, Lines);
	false ->
	    {error, function_not_found}
    end.

del_break_in(Mod, Func, Arity) when is_atom(Mod), is_atom(Func), is_integer(Arity) ->
    case dbg_iserver:safe_call({is_interpreted, Mod, Func, Arity}) of
	{true, Clauses} ->
	    Lines = first_lines(Clauses),
	    lists:foreach(fun(Line) -> delete_break(Mod, Line) end,
			  Lines);
	false ->
	    {error, function_not_found}
    end.

first_lines(Clauses) ->
    lists:map(fun(Clause) -> element(2, hd(element(5, Clause))) end,
	      Clauses).

no_break() ->
    dbg_iserver:safe_cast(no_break).

no_break(Mod) when is_atom(Mod) ->
    dbg_iserver:safe_cast({no_break, Mod}).

disable_break(Mod, Line) when is_atom(Mod), is_integer(Line) ->
    dbg_iserver:safe_cast({break_option, {Mod, Line}, status, inactive}).
    
enable_break(Mod, Line) when is_atom(Mod), is_integer(Line) ->
    dbg_iserver:safe_cast({break_option, {Mod, Line}, status, active}).

action_at_break(Mod, Line, Action) when is_atom(Mod), is_integer(Line) ->
    check_action(Action),
    dbg_iserver:safe_cast({break_option, {Mod, Line}, action, Action}).

check_action(enable) -> true;
check_action(disable) -> true;
check_action(delete) -> true.

test_at_break(Mod, Line, Function) when is_atom(Mod), is_integer(Line) ->
    check_function(Function),
    dbg_iserver:safe_cast({break_option, {Mod, Line}, condition, Function}).

check_function({Mod, Func}) when is_atom(Mod), is_atom(Func) -> true.

get_binding(Var, Bs) ->
    dbg_icmd:get_binding(Var, Bs).

all_breaks() ->
    dbg_iserver:safe_call(all_breaks).
all_breaks(Mod) when is_atom(Mod) ->
    dbg_iserver:safe_call({all_breaks, Mod}).

%%--------------------------------------------------------------------
%% snapshot() -> [{Pid, Init, Status, Info}]
%%   Pid = pid()
%%   Init = atom()  First interpreted function
%%   Status = idle | running | waiting | break | exit
%%   Info = {} | {Mod, Line} | ExitReason
%%     Mod = atom()
%%     Line = integer()
%%     ExitReason = term()
%%--------------------------------------------------------------------
snapshot() ->
    dbg_iserver:safe_call(snapshot).

%%--------------------------------------------------------------------
%% clear()
%%--------------------------------------------------------------------
clear() ->
    dbg_iserver:safe_cast(clear).
    
%%--------------------------------------------------------------------
%% continue(Pid) -> ok | {error, not_interpreted}
%% continue(X, Y, Z) -> ok | {error, not_interpreted}
%%--------------------------------------------------------------------
continue(Pid) when is_pid(Pid) ->
    case dbg_iserver:safe_call({get_meta, Pid}) of
	{ok, Meta} when is_pid(Meta) ->
	    dbg_icmd:continue(Meta),
	    ok;
	Error ->
	    Error
    end.
    
continue(X, Y, Z) when is_integer(X), is_integer(Y), is_integer(Z) ->
    continue(c:pid(X, Y, Z)).


%%====================================================================
%% External exports only to be used by Debugger
%%====================================================================

%%--------------------------------------------------------------------
%% start()
%% stop()
%% Functions for starting and stopping dbg_iserver explicitly.
%%--------------------------------------------------------------------
start() -> dbg_iserver:start().
stop() ->
    lists:foreach(
      fun(Mod) ->
	      everywhere(distributed,
			 fun() ->
				 erts_debug:breakpoint({Mod,'_','_'}, false)