/* dynl.c - dynamic linking * * Copyright (C) 1990, 91, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002 Free Software Foundation, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this software; see the file COPYING. If not, write to * the Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307 USA * * As a special exception, the Free Software Foundation gives permission * for additional uses of the text contained in its release of GUILE. * * The exception is that, if you link the GUILE library with other files * to produce an executable, this does not by itself cause the * resulting executable to be covered by the GNU General Public License. * Your use of that executable is in no way restricted on account of * linking the GUILE library code into it. * * This exception does not however invalidate any other reasons why * the executable file might be covered by the GNU General Public License. * * This exception applies only to the code released by the * Free Software Foundation under the name GUILE. If you copy * code from other Free Software Foundation releases into a copy of * GUILE, as the General Public License permits, the exception does * not apply to the code that you add in this way. To avoid misleading * anyone as to the status of such modified files, you must delete * this exception notice from them. * * If you write modifications of your own for GUILE, it is your choice * whether to permit this exception to apply to your modifications. * If you do not wish that, delete this exception notice. */ /* "dynl.c" dynamically link&load object files. Author: Aubrey Jaffer Modified for libguile by Marius Vollmer */ #if 0 /* Disabled until we know for sure that it isn't needed */ /* XXX - This is only here to drag in a definition of __eprintf. This is needed for proper operation of dynamic linking. The real solution would probably be a shared libgcc. */ #undef NDEBUG #include static void maybe_drag_in_eprintf () { assert (!maybe_drag_in_eprintf); } #endif #include #include #include "libguile/_scm.h" #include "libguile/dynl.h" #include "libguile/smob.h" #include "libguile/keywords.h" #include "libguile/ports.h" #include "libguile/strings.h" #include "libguile/deprecation.h" #include "libguile/lang.h" #include "libguile/validate.h" #include "guile-ltdl.h" /* From the libtool manual: "Note that libltdl is not threadsafe, i.e. a multithreaded application has to use a mutex for libltdl.". Guile does not currently support pre-emptive threads, so there is no mutex. Previously SCM_DEFER_INTS and SCM_ALLOW_INTS were used: they are mentioned here in case somebody is grepping for thread problems ;) */ static void * sysdep_dynl_link (const char *fname, const char *subr) { scm_lt_dlhandle handle; handle = scm_lt_dlopenext (fname); if (NULL == handle) { SCM fn; SCM msg; fn = scm_makfrom0str (fname); msg = scm_makfrom0str (scm_lt_dlerror ()); scm_misc_error (subr, "file: ~S, message: ~S", scm_list_2 (fn, msg)); } return (void *) handle; } static void sysdep_dynl_unlink (void *handle, const char *subr) { if (scm_lt_dlclose ((scm_lt_dlhandle) handle)) { scm_misc_error (subr, (char *) scm_lt_dlerror (), SCM_EOL); } } static void * sysdep_dynl_func (const char *symb, void *handle, const char *subr) { void *fptr; fptr = scm_lt_dlsym ((scm_lt_dlhandle) handle, symb); if (!fptr) { scm_misc_error (subr, (char *) scm_lt_dlerror (), SCM_EOL); } return fptr; } static void sysdep_dynl_init () { scm_lt_dlinit (); } scm_t_bits scm_tc16_dynamic_obj; #define DYNL_FILENAME(x) (SCM_CELL_OBJECT_1 (x)) #define DYNL_HANDLE(x) ((void *) SCM_CELL_WORD_2 (x)) #define SET_DYNL_HANDLE(x, v) (SCM_SET_CELL_WORD_2 ((x), (v))) static SCM dynl_obj_mark (SCM ptr) { return DYNL_FILENAME (ptr); } static int dynl_obj_print (SCM exp, SCM port, scm_print_state *pstate) { scm_puts ("#', port); return 1; } SCM_DEFINE (scm_dynamic_link, "dynamic-link", 1, 0, 0, (SCM filename), "Find the shared object (shared library) denoted by\n" "@var{filename} and link it into the running Guile\n" "application. The returned\n" "scheme object is a ``handle'' for the library which can\n" "be passed to @code{dynamic-func}, @code{dynamic-call} etc.\n\n" "Searching for object files is system dependent. Normally,\n" "if @var{filename} does have an explicit directory it will\n" "be searched for in locations\n" "such as @file{/usr/lib} and @file{/usr/local/lib}.") #define FUNC_NAME s_scm_dynamic_link { void *handle; SCM_VALIDATE_STRING (1, filename); handle = sysdep_dynl_link (SCM_STRING_CHARS (filename), FUNC_NAME); SCM_RETURN_NEWSMOB2 (scm_tc16_dynamic_obj, SCM_UNPACK (filename), handle); } #undef FUNC_NAME SCM_DEFINE (scm_dynamic_object_p, "dynamic-object?", 1, 0, 0, (SCM obj), "Return @code{#t} if @var{obj} is a dynamic object handle,\n" "or @code{#f} otherwise.") #define FUNC_NAME s_scm_dynamic_object_p { return SCM_BOOL (SCM_TYP16_PREDICATE (scm_tc16_dynamic_obj, obj)); } #undef FUNC_NAME SCM_DEFINE (scm_dynamic_unlink, "dynamic-unlink", 1, 0, 0, (SCM dobj), "Unlink a dynamic object from the application, if possible. The\n" "object must have been linked by @code{dynamic-link}, with \n" "@var{dobj} the corresponding handle. After this procedure\n" "is called, the handle can no longer be used to access the\n" "object.") #define FUNC_NAME s_scm_dynamic_unlink { /*fixme* GC-problem */ SCM_VALIDATE_SMOB (SCM_ARG1, dobj, dynamic_obj); if (DYNL_HANDLE (dobj) == NULL) { SCM_MISC_ERROR ("Already unlinked: ~S", dobj); } else { sysdep_dynl_unlink (DYNL_HANDLE (dobj), FUNC_NAME); SET_DYNL_HANDLE (dobj, NULL); return SCM_UNSPECIFIED; } } #undef FUNC_NAME SCM_DEFINE (scm_dynamic_func, "dynamic-func", 2, 0, 0, (SCM name, SCM dobj), "Return a ``handle'' for the function @var{name} in the\n" "shared object referred to by @var{dobj}. The handle\n" "can be passed to @code{dynamic-call} to actually\n" "call the function.\n\n" "Regardless whether your C compiler prepends an underscore\n" "@samp{_} to the global names in a program, you should\n" "@strong{not} include this underscore in @var{name}\n" "since it will be added automatically when necessary.") #define FUNC_NAME s_scm_dynamic_func { /* The returned handle is formed by casting the address of the function to a * long value and converting this to a scheme number */ void (*func) (); SCM_VALIDATE_STRING (1, name); /*fixme* GC-problem */ SCM_VALIDATE_SMOB (SCM_ARG2, dobj, dynamic_obj); if (DYNL_HANDLE (dobj) == NULL) { SCM_MISC_ERROR ("Already unlinked: ~S", dobj); } else { char *chars; chars = SCM_STRING_CHARS (name); func = (void (*) ()) sysdep_dynl_func (chars, DYNL_HANDLE (dobj), FUNC_NAME); return scm_ulong2num ((unsigned long) func); } } #undef FUNC_NAME SCM_DEFINE (scm_dynamic_call, "dynamic-call", 2, 0, 0, (SCM func, SCM dobj), "Call a C function in a dynamic object. Two styles of\n" "invocation are supported:\n\n" "@itemize @bullet\n" "@item @var{func} can be a function handle returned by\n" "@code{dynamic-func}. In this case @var{dobj} is\n" "ignored\n" "@item @var{func} can be a string with the name of the\n" "function to call, with @var{dobj} the handle of the\n" "dynamic object in which to find the function.\n" "This is equivalent to\n" "@smallexample\n\n" "(dynamic-call (dynamic-func @var{func} @var{dobj}) #f)\n" "@end smallexample\n" "@end itemize\n\n" "In either case, the function is passed no arguments\n" "and its return value is ignored.") #define FUNC_NAME s_scm_dynamic_call { void (*fptr) (); if (SCM_STRINGP (func)) func = scm_dynamic_func (func, dobj); fptr = (void (*) ()) SCM_NUM2ULONG (1, func); fptr (); return SCM_UNSPECIFIED; } #undef FUNC_NAME /* return a newly allocated array of char pointers to each of the strings in args, with a terminating NULL pointer. */ /* Note: a similar function is defined in posix.c, but we don't necessarily want to export it. */ static char **allocate_string_pointers (SCM args, int *num_args_return) { char **result; int n_args = scm_ilength (args); int i; SCM_ASSERT (n_args >= 0, args, SCM_ARGn, "allocate_string_pointers"); result = (char **) scm_malloc ((n_args + 1) * sizeof (char *)); result[n_args] = NULL; for (i = 0; i < n_args; i++) { SCM car = SCM_CAR (args); if (!SCM_STRINGP (car)) { free (result); scm_wrong_type_arg ("allocate_string_pointers", SCM_ARGn, car); } result[i] = SCM_STRING_CHARS (SCM_CAR (args)); args = SCM_CDR (args); } *num_args_return = n_args; return result; } SCM_DEFINE (scm_dynamic_args_call, "dynamic-args-call", 3, 0, 0, (SCM func, SCM dobj, SCM args), "Call the C function indicated by @var{func} and @var{dobj},\n" "just like @code{dynamic-call}, but pass it some arguments and\n" "return its return value. The C function is expected to take\n" "two arguments and return an @code{int}, just like @code{main}:\n" "@smallexample\n" "int c_func (int argc, char **argv);\n" "@end smallexample\n\n" "The parameter @var{args} must be a list of strings and is\n" "converted into an array of @code{char *}. The array is passed\n" "in @var{argv} and its size in @var{argc}. The return value is\n" "converted to a Scheme number and returned from the call to\n" "@code{dynamic-args-call}.") #define FUNC_NAME s_scm_dynamic_args_call { int (*fptr) (int argc, char **argv); int result, argc; char **argv; if (SCM_STRINGP (func)) func = scm_dynamic_func (func, dobj); fptr = (int (*) (int, char **)) SCM_NUM2ULONG (1, func); argv = allocate_string_pointers (args, &argc); /* if the procedure mutates its arguments, the original strings will be changed -- in Guile 1.6 and earlier, this wasn't the case since a new copy of each string was allocated. */ result = (*fptr) (argc, argv); free (argv); return SCM_MAKINUM (0L + result); } #undef FUNC_NAME void scm_init_dynamic_linking () { scm_tc16_dynamic_obj = scm_make_smob_type ("dynamic-object", 0); scm_set_smob_mark (scm_tc16_dynamic_obj, dynl_obj_mark); scm_set_smob_print (scm_tc16_dynamic_obj, dynl_obj_print); sysdep_dynl_init (); #include "libguile/dynl.x" } /* Local Variables: c-file-style: "gnu" End: */