/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@vu.nl
WWW: http://www.swi-prolog.org
Copyright (c) 1995-2016, University of Amsterdam
VU University Amsterdam
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
:- module(shlib,
[ load_foreign_library/1, % :LibFile
load_foreign_library/2, % :LibFile, +InstallFunc
unload_foreign_library/1, % +LibFile
unload_foreign_library/2, % +LibFile, +UninstallFunc
current_foreign_library/2, % ?LibFile, ?Public
reload_foreign_libraries/0,
% Directives
use_foreign_library/1, % :LibFile
use_foreign_library/2 % :LibFile, +InstallFunc
]).
:- use_module(library(lists), [reverse/2]).
:- set_prolog_flag(generate_debug_info, false).
/** <module> Utility library for loading foreign objects (DLLs, shared objects)
This section discusses the functionality of the (autoload)
library(shlib), providing an interface to manage shared libraries. We
describe the procedure for using a foreign resource (DLL in Windows and
shared object in Unix) called =mylib=.
First, one must assemble the resource and make it compatible to
SWI-Prolog. The details for this vary between platforms. The swipl-ld(1)
utility can be used to deal with this in a portable manner. The typical
commandline is:
==
swipl-ld -o mylib file.{c,o,cc,C} ...
==
Make sure that one of the files provides a global function
=|install_mylib()|= that initialises the module using calls to
PL_register_foreign(). Here is a simple example file mylib.c, which
creates a Windows MessageBox:
==
#include <windows.h>
#include <SWI-Prolog.h>
static foreign_t
pl_say_hello(term_t to)
{ char *a;
if ( PL_get_atom_chars(to, &a) )
{ MessageBox(NULL, a, "DLL test", MB_OK|MB_TASKMODAL);
PL_succeed;
}
PL_fail;
}
install_t
install_mylib()
{ PL_register_foreign("say_hello", 1, pl_say_hello, 0);
}
==
Now write a file mylib.pl:
==
:- module(mylib, [ say_hello/1 ]).
:- use_foreign_library(foreign(mylib)).
==
The file mylib.pl can be loaded as a normal Prolog file and provides the
predicate defined in C.
*/
:- meta_predicate
load_foreign_library(:),
load_foreign_library(:, +),
use_foreign_library(:),
use_foreign_library(:, +).
:- dynamic
loading/1, % Lib
error/2, % File, Error
foreign_predicate/2, % Lib, Pred
current_library/5. % Lib, Entry, Path, Module, Handle
:- volatile % Do not store in state
loading/1,
error/2,
foreign_predicate/2,
current_library/5.
:- ( current_prolog_flag(open_shared_object, true)
-> true
; print_message(warning, shlib(not_supported)) % error?
).
/*******************************
* DISPATCHING *
*******************************/
%! find_library(+LibSpec, -Lib, -Delete) is det.
%
% Find a foreign library from LibSpec. If LibSpec is available as
% a resource, the content of the resource is copied to a temporary
% file and Delete is unified with =true=.
find_library(Spec, TmpFile, true) :-
'$rc_handle'(RC),
term_to_atom(Spec, Name),
setup_call_cleanup(
'$rc_open'(RC, Name, shared, read, In),
setup_call_cleanup(
tmp_file_stream(binary, TmpFile, Out),
copy_stream_data(In, Out),
close(Out)),
close(In)),
!.
find_library(Spec, Lib, false) :-
absolute_file_name(Spec, Lib,
[ file_type(executable),
access(read),
file_errors(fail)
]),
!.
find_library(Spec, Spec, false) :-
atom(Spec),
!. % use machines finding schema
find_library(foreign(Spec), Spec, false) :-
atom(Spec),
!. % use machines finding schema
find_library(Spec, _, _) :-
throw(error(existence_error(source_sink, Spec), _)).
base(Path, Base) :-
atomic(Path),
!,
file_base_name(Path, File),
file_name_extension(Base, _Ext, File).
base(_/Path, Base) :-
!,
base(Path, Base).
base(Path, Base) :-
Path =.. [_,Arg],
base(Arg, Base).
entry(_, Function, Function) :-
Function \= default(_),
!.
entry(Spec, default(FuncBase), Function) :-
base(Spec, Base),
atomic_list_concat([FuncBase, Base], '_', Function).
entry(_, default(Function), Function).
/*******************************
* (UN)LOADING *
*******************************/
%! load_foreign_library(:FileSpec) is det.
%! load_foreign_library(:FileSpec, +Entry:atom) is det.
%
% Load a _|shared object|_ or _DLL_. After loading the Entry
% function is called without arguments. The default entry function
% is composed from =install_=, followed by the file base-name.
% E.g., the load-call below calls the function
% =|install_mylib()|=. If the platform prefixes extern functions
% with =_=, this prefix is added before calling.
%
% ==
% ...
% load_foreign_library(foreign(mylib)),
% ...
% ==
%
% @param FileSpec is a specification for absolute_file_name/3. If searching
% the file fails, the plain name is passed to the OS to try the default
% method of the OS for locating foreign objects. The default definition
% of file_search_path/2 searches <prolog home>/lib/<arch> on Unix and
% <prolog home>/bin on Windows.
%
% @see use_foreign_library/1,2 are intended for use in directives.
load_foreign_library(Library) :-
load_foreign_library(Library, default(install)).
load_foreign_library(Module:LibFile, Entry) :-
with_mutex('$foreign',
load_foreign_library(LibFile, Module, Entry)).
load_foreign_library(LibFile, _Module, _) :-
current_library(LibFile, _, _, _, _),
!.
load_foreign_library(LibFile, Module, DefEntry) :-
retractall(error(_, _)),
find_library(LibFile, Path, Delete),
asserta(loading(LibFile)),
retractall(foreign_predicate(LibFile, _)),
catch(Module:open_shared_object(Path, Handle), E, true),
( nonvar(E)
-> delete_foreign_lib(Delete, Path),
assert(error(Path, E)),
fail
; delete_foreign_lib(Delete, Path)
),
!,
( entry(LibFile, DefEntry, Entry),
Module:call_shared_object_function(Handle, Entry)
-> retractall(loading(LibFile)),
assert_shlib(LibFile, Entry, Path, Module, Handle)
; foreign_predicate(LibFile, _)
-> retractall(loading(LibFile)) % C++ object installed predicates
; retractall(loading(LibFile)),
retractall(foreign_predicate(LibFile, _)),
close_shared_object(Handle),
findall(Entry, entry(LibFile, DefEntry, Entry), Entries),
throw(error(existence_error(foreign_install_function,
install(Path, Entries)),
_))
).
load_foreign_library(LibFile, _, _) :-
retractall(loading(LibFile)),
( error(_Path, E)
-> retractall(error(_, _)),
throw(E)
; throw(error(existence_error(foreign_library, LibFile), _))
).
delete_foreign_lib(true, Path) :-
catch(delete_file(Path), _, true).
delete_foreign_lib(_, _).
%! use_foreign_library(+FileSpec) is det.
%! use_foreign_library(+FileSpec, +Entry:atom) is det.
%
% Load and install a foreign library as load_foreign_library/1,2
% and register the installation using initialization/2 with the
% option =now=. This is similar to using:
%
% ==
% :- initialization(load_foreign_library(foreign(mylib))).
% ==
%
% but using the initialization/1 wrapper causes the library to be
% loaded _after_ loading of the file in which it appears is
% completed, while use_foreign_library/1 loads the library
% _immediately_. I.e. the difference is only relevant if the
% remainder of the file uses functionality of the C-library.
use_foreign_library(FileSpec) :-
initialization(load_foreign_library(FileSpec), now).
use_foreign_library(FileSpec, Entry) :-
initialization(load_foreign_library(FileSpec, Entry), now).
%! unload_foreign_library(+FileSpec) is det.
%! unload_foreign_library(+FileSpec, +Exit:atom) is det.
%
% Unload a _|shared object|_ or _DLL_. After calling the Exit
% function, the shared object is removed from the process. The
% default exit function is composed from =uninstall_=, followed by
% the file base-name.
unload_foreign_library(LibFile) :-
unload_foreign_library(LibFile, default(uninstall)).
unload_foreign_library(LibFile, DefUninstall) :-
with_mutex('$foreign', do_unload(LibFile, DefUninstall)).
do_unload(LibFile, DefUninstall) :-
current_library(LibFile, _, _, Module, Handle),
retractall(current_library(LibFile, _, _, _, _)),
( entry(LibFile, DefUninstall, Uninstall),
Module:call_shared_object_function(Handle, Uninstall)
-> true
; true
),
abolish_foreign(LibFile),
close_shared_object(Handle).
abolish_foreign(LibFile) :-
( retract(foreign_predicate(LibFile, Module:Head)),
functor(Head, Name, Arity),
abolish(Module:Name, Arity),
fail
; true
).
system:'$foreign_registered'(M, H) :-
( loading(Lib)
-> true
; Lib = '<spontaneous>'
),
assert(foreign_predicate(Lib, M:H)).
assert_shlib(File, Entry, Path, Module, Handle) :-
retractall(current_library(File, _, _, _, _)),
asserta(current_library(File, Entry, Path, Module, Handle)).
/*******************************
* ADMINISTRATION *
*******************************/
%! current_foreign_library(?File, ?Public)
%
% Query currently loaded shared libraries.
current_foreign_library(File, Public) :-
current_library(File, _Entry, _Path, _Module, _Handle),
findall(Pred, foreign_predicate(File, Pred), Public).
/*******************************
* RELOAD *
*******************************/
%! reload_foreign_libraries
%
% Reload all foreign libraries loaded (after restore of a state
% created using qsave_program/2.
reload_foreign_libraries :-
findall(lib(File, Entry, Module),
( retract(current_library(File, Entry, _, Module, _)),
File \== -
),
Libs),
reverse(Libs, Reversed),
reload_libraries(Reversed).
reload_libraries([]).
reload_libraries([lib(File, Entry, Module)|T]) :-
( load_foreign_library(File, Module, Entry)
-> true
; print_message(error, shlib(File, load_failed))
),
reload_libraries(T).
/*******************************
* CLEANUP (WINDOWS ...) *
*******************************/
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Called from Halt() in pl-os.c (if it is defined), *after* all at_halt/1
hooks have been executed, and after dieIO(), closing and flushing all
files has been called.
On Unix, this is not very useful, and can only lead to conflicts.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
unload_all_foreign_libraries :-
current_prolog_flag(unload_foreign_libraries, true),
!,
forall(current_library(File, _, _, _, _),
unload_foreign(File)).
unload_all_foreign_libraries.
%! unload_foreign(+File)
%
% Unload the given foreign file and all `spontaneous' foreign
% predicates created afterwards. Handling these spontaneous
% predicates is a bit hard, as we do not know who created them and
% on which library they depend.
unload_foreign(File) :-
unload_foreign_library(File),
( clause(foreign_predicate(Lib, M:H), true, Ref),
( Lib == '<spontaneous>'
-> functor(H, Name, Arity),
abolish(M:Name, Arity),
erase(Ref),
fail
; !
)
-> true
; true
).
/*******************************
* MESSAGES *
*******************************/
:- multifile
prolog:message//1,
prolog:error_message//1.
prolog:message(shlib(LibFile, load_failed)) -->
[ '~w: Failed to load file'-[LibFile] ].
prolog:message(shlib(not_supported)) -->
[ 'Emulator does not support foreign libraries' ].
prolog:error_message(existence_error(foreign_install_function,
install(Lib, List))) -->
[ 'No install function in ~q'-[Lib], nl,
'\tTried: ~q'-[List]
].