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author | Erlang/OTP <otp@erlang.org> | 2009-11-20 14:54:40 +0000 |
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committer | Erlang/OTP <otp@erlang.org> | 2009-11-20 14:54:40 +0000 |
commit | 84adefa331c4159d432d22840663c38f155cd4c1 (patch) | |
tree | bff9a9c66adda4df2106dfd0e5c053ab182a12bd /lib/pman/src/pman_relay.erl | |
download | otp-84adefa331c4159d432d22840663c38f155cd4c1.tar.gz otp-84adefa331c4159d432d22840663c38f155cd4c1.tar.bz2 otp-84adefa331c4159d432d22840663c38f155cd4c1.zip |
The R13B03 release.OTP_R13B03
Diffstat (limited to 'lib/pman/src/pman_relay.erl')
-rw-r--r-- | lib/pman/src/pman_relay.erl | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/lib/pman/src/pman_relay.erl b/lib/pman/src/pman_relay.erl new file mode 100644 index 0000000000..289765492f --- /dev/null +++ b/lib/pman/src/pman_relay.erl @@ -0,0 +1,127 @@ +%% +%% %CopyrightBegin% +%% +%% Copyright Ericsson AB 1997-2009. All Rights Reserved. +%% +%% 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 online 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. +%% +%% %CopyrightEnd% +%% +%%---------------------------------------------------------------------- +%% Purpose : Interface function to relay calls (esp. trace calls) +%% to processes on other nodes. Some of the calls +%% are conditionally relayed. +%%---------------------------------------------------------------------- + +-module(pman_relay). + +%%-compile(export_all). +-export([start/1, + ok_to_trace/1, + trac/3]). + + +-include("assert.hrl"). + +%% -------------------------------------------------------------- +%% DISTRIBUTION +%% -------------------------------------------------------------- +%% (???) Process dictionary alert!!! +%% +%% Since we are not allowed to do erlang:trace/3 on remote +%% processe we create a help process at the remote node to +%% do the job for us +%% --------------------------------------------------------------- + +start(P) when is_pid(P), node(P)/=node() -> + + %% Remote supervision, relaying necessary + + put(relay, spawn_link(node(P), pman_relay_server, init, [self()])); + + +start(_) -> + + %% Local supervision, no relaying + + ignore. + + + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% ok_to_trace/1 - Tests wheter we can actually start tracing +%% a process. +%% +%% Arguments: +%% Pid Pid of the process to trace (on local or remote node) +%% +%% Returns +%% true If it is OK to trace the process +%% false If the process is already traced, or some other +%% condition prevents it from being traced. + +ok_to_trace(Pid) when node(Pid) == node()-> + + %% Local trace, no relaying + + case catch erlang:trace(Pid, false, [send]) of + 1 -> + true; + _Otherwise -> + false + end; +ok_to_trace(Pid) -> + + %% Remote trace, relaying necessary + + PidRelay = get(relay), + PidRelay ! {ok_to_trace, self(), Pid}, + receive + {ok_to_trace, PidRelay} -> + true; + {not_ok_to_trace, PidRelay} -> + false; + _Otherwise -> + ?ALWAYS_ASSERT("Unexpected message from relay process") + after + 5000 -> + false + end. + + + + + + +%% --------------------------------------------------------------- +%% Possibly send a request to do tracing to a remote node. +%% --------------------------------------------------------------- + +trac(Pid, How, Flag) when node(Pid) == node() -> + + %% Local trace, no relaying necessary + + + case catch erlang:trace(Pid, How, Flag) of + 1 -> ok; + _ -> pman_win:format("** Illegal trace request ** \n", []) + end; + +trac(Pid, How, Flag) -> + + + + %% Remote trace, relaying necessary + + get(relay) ! {self(), erlang, trace, [Pid, How, Flag]}. + |