From 84adefa331c4159d432d22840663c38f155cd4c1 Mon Sep 17 00:00:00 2001
From: Erlang/OTP <otp@erlang.org>
Date: Fri, 20 Nov 2009 14:54:40 +0000
Subject: The R13B03 release.

---
 lib/kernel/src/erl_ddll.erl | 150 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 150 insertions(+)
 create mode 100644 lib/kernel/src/erl_ddll.erl

(limited to 'lib/kernel/src/erl_ddll.erl')

diff --git a/lib/kernel/src/erl_ddll.erl b/lib/kernel/src/erl_ddll.erl
new file mode 100644
index 0000000000..88f91de24f
--- /dev/null
+++ b/lib/kernel/src/erl_ddll.erl
@@ -0,0 +1,150 @@
+%%
+%% %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%
+%%
+%% Dynamic Driver Loader and Linker
+%%
+%% Interface for dynamic library/shared object driver loader/linker.
+%% Provides methods for loading, unloading and listing drivers.
+
+-module(erl_ddll).
+
+-export([load_driver/2, load/2, 
+	 unload_driver/1, unload/1, reload/2, reload_driver/2, 
+	 format_error/1,info/1,info/0, start/0, stop/0]).
+
+%%----------------------------------------------------------------------------
+
+-spec start() -> {'error', {'already_started', 'undefined'}}.
+
+start() ->
+    {error, {already_started,undefined}}.
+
+-spec stop() -> 'ok'.
+
+stop() ->
+    ok.
+
+-spec load_driver(Path :: string() | atom(), Driver :: string() | atom()) ->
+	'ok' | {'error', any()}.
+
+load_driver(Path, Driver) ->
+    do_load_driver(Path, Driver, [{driver_options,[kill_ports]}]).
+
+-spec load(Path :: string() | atom(), Driver :: string() | atom()) ->
+	'ok' | {'error', any()}.
+
+load(Path, Driver) ->
+    do_load_driver(Path, Driver, []).
+
+do_load_driver(Path, Driver, DriverFlags) ->
+    case erl_ddll:try_load(Path, Driver,[{monitor,pending_driver}]++DriverFlags) of
+	{error, inconsistent} ->
+	    {error,bad_driver_name}; % BC 
+	{error, What} ->
+	    {error,What};
+	{ok, already_loaded} ->
+	    ok;
+	{ok,loaded} ->
+	    ok;
+	{ok, pending_driver, Ref} ->
+	    receive
+		{'DOWN', Ref, driver, _, load_cancelled} ->
+		    {error, load_cancelled};
+		{'UP', Ref, driver, _, permanent} ->
+		    {error, permanent}; 
+		{'DOWN', Ref, driver, _, {load_failure, Failure}} ->
+		    {error, Failure};
+		{'UP', Ref, driver, _, loaded} ->
+		    ok
+	    end
+    end.
+
+do_unload_driver(Driver,Flags) ->
+    case erl_ddll:try_unload(Driver,Flags) of
+	{error,What} ->
+	    {error,What};
+	{ok, pending_process} ->
+	    ok;
+	{ok, unloaded} ->
+	    ok;
+	{ok, pending_driver} ->
+	    ok;
+	{ok, pending_driver, Ref} ->
+	    receive
+		{'UP', Ref, driver, _, permanent} ->
+		    {error, permanent}; 
+		{'UP', Ref, driver, _, unload_cancelled} ->
+		    ok;
+		{'DOWN', Ref, driver, _, unloaded} ->
+		    ok
+	    end
+    end.
+
+-spec unload_driver(Driver :: string() | atom()) -> 'ok' | {'error', any()}.
+
+unload_driver(Driver) ->
+    do_unload_driver(Driver,[{monitor,pending_driver},kill_ports]).
+
+-spec unload(Driver :: string() | atom()) -> 'ok' | {'error', any()}.
+
+unload(Driver) ->
+    do_unload_driver(Driver,[]).
+
+-spec reload(Path :: string() | atom(), Driver :: string() | atom()) ->
+	'ok' | {'error', any()}.
+
+reload(Path,Driver) ->
+    do_load_driver(Path, Driver, [{reload,pending_driver}]).
+
+-spec reload_driver(Path :: string() | atom(), Driver :: string() | atom()) ->
+	'ok' | {'error', any()}.
+
+reload_driver(Path,Driver) ->
+    do_load_driver(Path, Driver, [{reload,pending_driver},
+				  {driver_options,[kill_ports]}]).			    
+
+-spec format_error(Code :: atom()) -> string().
+
+format_error(Code) ->
+    case Code of
+	% This is the only error code returned only from erlang code...
+	% 'permanent' has a translation in the emulator, even though the erlang code uses it to...
+	load_cancelled ->
+	    "Loading was cancelled from other process";
+	_ ->
+	    erl_ddll:format_error_int(Code)
+    end.
+
+-spec info(Driver :: string() | atom()) -> [{atom(), any()}].
+ 
+info(Driver) ->
+    [{processes, erl_ddll:info(Driver,processes)},
+     {driver_options, erl_ddll:info(Driver,driver_options)},
+     {port_count, erl_ddll:info(Driver,port_count)},
+     {linked_in_driver, erl_ddll:info(Driver,linked_in_driver)},
+     {permanent, erl_ddll:info(Driver,permanent)},
+     {awaiting_load,  erl_ddll:info(Driver,awaiting_load)},
+     {awaiting_unload, erl_ddll:info(Driver,awaiting_unload)}].
+
+-spec info() -> [{string(), [{atom(), any()}]}].
+
+info() ->
+    {ok,DriverList} = erl_ddll:loaded_drivers(),
+    [{X,Y} || X <- DriverList,
+	       Y <- [catch info(X)],
+	       is_list(Y), not lists:member({linked_in_driver,true},Y)]. 
-- 
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