| 1 | /* dynl.c - dynamic linking |
| 2 | * |
| 3 | * Copyright (C) 1990, 91, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002, |
| 4 | * 2003, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. |
| 5 | * |
| 6 | * This library is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU Lesser General Public License |
| 8 | * as published by the Free Software Foundation; either version 3 of |
| 9 | * the License, or (at your option) any later version. |
| 10 | * |
| 11 | * This library is distributed in the hope that it will be useful, but |
| 12 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | * Lesser General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Lesser General Public |
| 17 | * License along with this library; if not, write to the Free Software |
| 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 19 | * 02110-1301 USA |
| 20 | */ |
| 21 | |
| 22 | |
| 23 | |
| 24 | #ifdef HAVE_CONFIG_H |
| 25 | # include <config.h> |
| 26 | #endif |
| 27 | |
| 28 | #include <alloca.h> |
| 29 | #include <string.h> |
| 30 | |
| 31 | /* "dynl.c" dynamically link&load object files. |
| 32 | Author: Aubrey Jaffer |
| 33 | Modified for libguile by Marius Vollmer */ |
| 34 | |
| 35 | #if 0 /* Disabled until we know for sure that it isn't needed */ |
| 36 | /* XXX - This is only here to drag in a definition of __eprintf. This |
| 37 | is needed for proper operation of dynamic linking. The real |
| 38 | solution would probably be a shared libgcc. */ |
| 39 | |
| 40 | #undef NDEBUG |
| 41 | #include <assert.h> |
| 42 | |
| 43 | static void |
| 44 | maybe_drag_in_eprintf () |
| 45 | { |
| 46 | assert (!maybe_drag_in_eprintf); |
| 47 | } |
| 48 | #endif |
| 49 | |
| 50 | #include <stdlib.h> |
| 51 | #include <stdio.h> |
| 52 | #include <string.h> |
| 53 | |
| 54 | #include "libguile/_scm.h" |
| 55 | #include "libguile/libpath.h" |
| 56 | #include "libguile/dynl.h" |
| 57 | #include "libguile/smob.h" |
| 58 | #include "libguile/keywords.h" |
| 59 | #include "libguile/ports.h" |
| 60 | #include "libguile/strings.h" |
| 61 | #include "libguile/deprecation.h" |
| 62 | #include "libguile/validate.h" |
| 63 | #include "libguile/dynwind.h" |
| 64 | #include "libguile/foreign.h" |
| 65 | #include "libguile/gc.h" |
| 66 | |
| 67 | #include <ltdl.h> |
| 68 | |
| 69 | /* |
| 70 | From the libtool manual: "Note that libltdl is not threadsafe, |
| 71 | i.e. a multithreaded application has to use a mutex for libltdl.". |
| 72 | |
| 73 | Guile does not currently support pre-emptive threads, so there is no |
| 74 | mutex. Previously SCM_CRITICAL_SECTION_START and |
| 75 | SCM_CRITICAL_SECTION_END were used: they are mentioned here in case |
| 76 | somebody is grepping for thread problems ;) |
| 77 | */ |
| 78 | /* njrev: not threadsafe, protection needed as described above */ |
| 79 | |
| 80 | |
| 81 | /* LT_PATH_SEP-separated extension library search path, searched last */ |
| 82 | static char *system_extensions_path; |
| 83 | |
| 84 | static void * |
| 85 | sysdep_dynl_link (const char *fname, const char *subr) |
| 86 | { |
| 87 | lt_dlhandle handle; |
| 88 | |
| 89 | if (fname == NULL) |
| 90 | /* Return a handle for the program as a whole. */ |
| 91 | handle = lt_dlopen (NULL); |
| 92 | else |
| 93 | { |
| 94 | handle = lt_dlopenext (fname); |
| 95 | |
| 96 | if (handle == NULL |
| 97 | #ifdef LT_DIRSEP_CHAR |
| 98 | && strchr (fname, LT_DIRSEP_CHAR) == NULL |
| 99 | #endif |
| 100 | && strchr (fname, '/') == NULL) |
| 101 | { |
| 102 | /* FNAME contains no directory separators and was not in the |
| 103 | usual library search paths, so now we search for it in |
| 104 | SYSTEM_EXTENSIONS_PATH. */ |
| 105 | char *fname_attempt |
| 106 | = scm_gc_malloc_pointerless (strlen (system_extensions_path) |
| 107 | + strlen (fname) + 2, |
| 108 | "dynl fname_attempt"); |
| 109 | char *path; /* remaining path to search */ |
| 110 | char *end; /* end of current path component */ |
| 111 | char *s; |
| 112 | |
| 113 | /* Iterate over the components of SYSTEM_EXTENSIONS_PATH */ |
| 114 | for (path = system_extensions_path; |
| 115 | *path != '\0'; |
| 116 | path = (*end == '\0') ? end : (end + 1)) |
| 117 | { |
| 118 | /* Find end of path component */ |
| 119 | end = strchr (path, LT_PATHSEP_CHAR); |
| 120 | if (end == NULL) |
| 121 | end = strchr (path, '\0'); |
| 122 | |
| 123 | /* Skip empty path components */ |
| 124 | if (path == end) |
| 125 | continue; |
| 126 | |
| 127 | /* Construct FNAME_ATTEMPT, starting with path component */ |
| 128 | s = fname_attempt; |
| 129 | memcpy (s, path, end - path); |
| 130 | s += end - path; |
| 131 | |
| 132 | /* Append directory separator, but avoid duplicates */ |
| 133 | if (s[-1] != '/' |
| 134 | #ifdef LT_DIRSEP_CHAR |
| 135 | && s[-1] != LT_DIRSEP_CHAR |
| 136 | #endif |
| 137 | ) |
| 138 | *s++ = '/'; |
| 139 | |
| 140 | /* Finally, append FNAME (including null terminator) */ |
| 141 | strcpy (s, fname); |
| 142 | |
| 143 | /* Try to load it, and terminate the search if successful */ |
| 144 | handle = lt_dlopenext (fname_attempt); |
| 145 | if (handle != NULL) |
| 146 | break; |
| 147 | } |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | if (handle == NULL) |
| 152 | { |
| 153 | SCM fn; |
| 154 | SCM msg; |
| 155 | |
| 156 | fn = fname != NULL ? scm_from_locale_string (fname) : SCM_BOOL_F; |
| 157 | msg = scm_from_locale_string (lt_dlerror ()); |
| 158 | scm_misc_error (subr, "file: ~S, message: ~S", scm_list_2 (fn, msg)); |
| 159 | } |
| 160 | |
| 161 | return (void *) handle; |
| 162 | } |
| 163 | |
| 164 | static void |
| 165 | sysdep_dynl_unlink (void *handle, const char *subr) |
| 166 | { |
| 167 | if (lt_dlclose ((lt_dlhandle) handle)) |
| 168 | { |
| 169 | scm_misc_error (subr, (char *) lt_dlerror (), SCM_EOL); |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | static void * |
| 174 | sysdep_dynl_value (const char *symb, void *handle, const char *subr) |
| 175 | { |
| 176 | void *fptr; |
| 177 | |
| 178 | fptr = lt_dlsym ((lt_dlhandle) handle, symb); |
| 179 | if (!fptr) |
| 180 | scm_misc_error (subr, "Symbol not found: ~a", |
| 181 | scm_list_1 (scm_from_locale_string (symb))); |
| 182 | return fptr; |
| 183 | } |
| 184 | |
| 185 | static void |
| 186 | sysdep_dynl_init () |
| 187 | { |
| 188 | char *env; |
| 189 | |
| 190 | lt_dlinit (); |
| 191 | |
| 192 | /* Initialize 'system_extensions_path' from |
| 193 | $GUILE_SYSTEM_EXTENSIONS_PATH, or if that's not set: |
| 194 | <SCM_LIB_DIR> <LT_PATHSEP_CHAR> <SCM_EXTENSIONS_DIR>. |
| 195 | |
| 196 | 'lt_dladdsearchdir' can't be used because it is searched before |
| 197 | the system-dependent search path, which is the one 'libtool |
| 198 | --mode=execute -dlopen' fiddles with (info "(libtool) Libltdl |
| 199 | Interface"). See |
| 200 | <http://lists.gnu.org/archive/html/guile-devel/2010-11/msg00095.html>. |
| 201 | |
| 202 | The environment variables $LTDL_LIBRARY_PATH and $LD_LIBRARY_PATH |
| 203 | can't be used because they would be propagated to subprocesses |
| 204 | which may cause problems for other programs. See |
| 205 | <http://lists.gnu.org/archive/html/guile-devel/2012-09/msg00037.html> */ |
| 206 | |
| 207 | env = getenv ("GUILE_SYSTEM_EXTENSIONS_PATH"); |
| 208 | if (env) |
| 209 | system_extensions_path = env; |
| 210 | else |
| 211 | { |
| 212 | system_extensions_path |
| 213 | = scm_gc_malloc_pointerless (strlen (SCM_LIB_DIR) |
| 214 | + strlen (SCM_EXTENSIONS_DIR) + 2, |
| 215 | "system_extensions_path"); |
| 216 | sprintf (system_extensions_path, "%s%c%s", |
| 217 | SCM_LIB_DIR, LT_PATHSEP_CHAR, SCM_EXTENSIONS_DIR); |
| 218 | } |
| 219 | } |
| 220 | |
| 221 | scm_t_bits scm_tc16_dynamic_obj; |
| 222 | |
| 223 | #define DYNL_FILENAME SCM_SMOB_OBJECT |
| 224 | #define DYNL_HANDLE(x) ((void *) SCM_SMOB_DATA_2 (x)) |
| 225 | #define SET_DYNL_HANDLE(x, v) (SCM_SET_SMOB_DATA_2 ((x), (scm_t_bits) (v))) |
| 226 | |
| 227 | |
| 228 | |
| 229 | static int |
| 230 | dynl_obj_print (SCM exp, SCM port, scm_print_state *pstate) |
| 231 | { |
| 232 | scm_puts_unlocked ("#<dynamic-object ", port); |
| 233 | scm_iprin1 (DYNL_FILENAME (exp), port, pstate); |
| 234 | if (DYNL_HANDLE (exp) == NULL) |
| 235 | scm_puts_unlocked (" (unlinked)", port); |
| 236 | scm_putc_unlocked ('>', port); |
| 237 | return 1; |
| 238 | } |
| 239 | |
| 240 | |
| 241 | SCM_DEFINE (scm_dynamic_link, "dynamic-link", 0, 1, 0, |
| 242 | (SCM filename), |
| 243 | "Find the shared object (shared library) denoted by\n" |
| 244 | "@var{filename} and link it into the running Guile\n" |
| 245 | "application. The returned\n" |
| 246 | "scheme object is a ``handle'' for the library which can\n" |
| 247 | "be passed to @code{dynamic-func}, @code{dynamic-call} etc.\n\n" |
| 248 | "Searching for object files is system dependent. Normally,\n" |
| 249 | "if @var{filename} does have an explicit directory it will\n" |
| 250 | "be searched for in locations\n" |
| 251 | "such as @file{/usr/lib} and @file{/usr/local/lib}.\n\n" |
| 252 | "When @var{filename} is omitted, a @dfn{global symbol handle} is\n" |
| 253 | "returned. This handle provides access to the symbols\n" |
| 254 | "available to the program at run-time, including those exported\n" |
| 255 | "by the program itself and the shared libraries already loaded.\n") |
| 256 | #define FUNC_NAME s_scm_dynamic_link |
| 257 | { |
| 258 | void *handle; |
| 259 | char *file; |
| 260 | |
| 261 | scm_dynwind_begin (0); |
| 262 | |
| 263 | if (SCM_UNBNDP (filename)) |
| 264 | file = NULL; |
| 265 | else |
| 266 | { |
| 267 | file = scm_to_locale_string (filename); |
| 268 | scm_dynwind_free (file); |
| 269 | } |
| 270 | |
| 271 | handle = sysdep_dynl_link (file, FUNC_NAME); |
| 272 | scm_dynwind_end (); |
| 273 | |
| 274 | SCM_RETURN_NEWSMOB2 (scm_tc16_dynamic_obj, |
| 275 | SCM_UNBNDP (filename) |
| 276 | ? SCM_UNPACK (SCM_BOOL_F) : SCM_UNPACK (filename), |
| 277 | handle); |
| 278 | } |
| 279 | #undef FUNC_NAME |
| 280 | |
| 281 | |
| 282 | SCM_DEFINE (scm_dynamic_object_p, "dynamic-object?", 1, 0, 0, |
| 283 | (SCM obj), |
| 284 | "Return @code{#t} if @var{obj} is a dynamic object handle,\n" |
| 285 | "or @code{#f} otherwise.") |
| 286 | #define FUNC_NAME s_scm_dynamic_object_p |
| 287 | { |
| 288 | return scm_from_bool (SCM_TYP16_PREDICATE (scm_tc16_dynamic_obj, obj)); |
| 289 | } |
| 290 | #undef FUNC_NAME |
| 291 | |
| 292 | |
| 293 | SCM_DEFINE (scm_dynamic_unlink, "dynamic-unlink", 1, 0, 0, |
| 294 | (SCM dobj), |
| 295 | "Unlink a dynamic object from the application, if possible. The\n" |
| 296 | "object must have been linked by @code{dynamic-link}, with \n" |
| 297 | "@var{dobj} the corresponding handle. After this procedure\n" |
| 298 | "is called, the handle can no longer be used to access the\n" |
| 299 | "object.") |
| 300 | #define FUNC_NAME s_scm_dynamic_unlink |
| 301 | { |
| 302 | /*fixme* GC-problem */ |
| 303 | SCM_VALIDATE_SMOB (SCM_ARG1, dobj, dynamic_obj); |
| 304 | if (DYNL_HANDLE (dobj) == NULL) { |
| 305 | SCM_MISC_ERROR ("Already unlinked: ~S", scm_list_1 (dobj)); |
| 306 | } else { |
| 307 | sysdep_dynl_unlink (DYNL_HANDLE (dobj), FUNC_NAME); |
| 308 | SET_DYNL_HANDLE (dobj, NULL); |
| 309 | return SCM_UNSPECIFIED; |
| 310 | } |
| 311 | } |
| 312 | #undef FUNC_NAME |
| 313 | |
| 314 | |
| 315 | SCM_DEFINE (scm_dynamic_pointer, "dynamic-pointer", 2, 0, 0, |
| 316 | (SCM name, SCM dobj), |
| 317 | "Return a ``wrapped pointer'' to the symbol @var{name}\n" |
| 318 | "in the shared object referred to by @var{dobj}. The returned\n" |
| 319 | "pointer points to a C object.\n\n" |
| 320 | "Regardless whether your C compiler prepends an underscore\n" |
| 321 | "@samp{_} to the global names in a program, you should\n" |
| 322 | "@strong{not} include this underscore in @var{name}\n" |
| 323 | "since it will be added automatically when necessary.") |
| 324 | #define FUNC_NAME s_scm_dynamic_pointer |
| 325 | { |
| 326 | void *val; |
| 327 | |
| 328 | SCM_VALIDATE_STRING (1, name); |
| 329 | SCM_VALIDATE_SMOB (SCM_ARG2, dobj, dynamic_obj); |
| 330 | |
| 331 | if (DYNL_HANDLE (dobj) == NULL) |
| 332 | SCM_MISC_ERROR ("Already unlinked: ~S", dobj); |
| 333 | else |
| 334 | { |
| 335 | char *chars; |
| 336 | |
| 337 | scm_dynwind_begin (0); |
| 338 | chars = scm_to_locale_string (name); |
| 339 | scm_dynwind_free (chars); |
| 340 | val = sysdep_dynl_value (chars, DYNL_HANDLE (dobj), FUNC_NAME); |
| 341 | scm_dynwind_end (); |
| 342 | |
| 343 | return scm_from_pointer (val, NULL); |
| 344 | } |
| 345 | } |
| 346 | #undef FUNC_NAME |
| 347 | |
| 348 | |
| 349 | SCM_DEFINE (scm_dynamic_func, "dynamic-func", 2, 0, 0, |
| 350 | (SCM name, SCM dobj), |
| 351 | "Return a ``handle'' for the function @var{name} in the\n" |
| 352 | "shared object referred to by @var{dobj}. The handle\n" |
| 353 | "can be passed to @code{dynamic-call} to actually\n" |
| 354 | "call the function.\n\n" |
| 355 | "Regardless whether your C compiler prepends an underscore\n" |
| 356 | "@samp{_} to the global names in a program, you should\n" |
| 357 | "@strong{not} include this underscore in @var{name}\n" |
| 358 | "since it will be added automatically when necessary.") |
| 359 | #define FUNC_NAME s_scm_dynamic_func |
| 360 | { |
| 361 | return scm_dynamic_pointer (name, dobj); |
| 362 | } |
| 363 | #undef FUNC_NAME |
| 364 | |
| 365 | |
| 366 | SCM_DEFINE (scm_dynamic_call, "dynamic-call", 2, 0, 0, |
| 367 | (SCM func, SCM dobj), |
| 368 | "Call a C function in a dynamic object. Two styles of\n" |
| 369 | "invocation are supported:\n\n" |
| 370 | "@itemize @bullet\n" |
| 371 | "@item @var{func} can be a function handle returned by\n" |
| 372 | "@code{dynamic-func}. In this case @var{dobj} is\n" |
| 373 | "ignored\n" |
| 374 | "@item @var{func} can be a string with the name of the\n" |
| 375 | "function to call, with @var{dobj} the handle of the\n" |
| 376 | "dynamic object in which to find the function.\n" |
| 377 | "This is equivalent to\n" |
| 378 | "@smallexample\n\n" |
| 379 | "(dynamic-call (dynamic-func @var{func} @var{dobj}) #f)\n" |
| 380 | "@end smallexample\n" |
| 381 | "@end itemize\n\n" |
| 382 | "In either case, the function is passed no arguments\n" |
| 383 | "and its return value is ignored.") |
| 384 | #define FUNC_NAME s_scm_dynamic_call |
| 385 | { |
| 386 | void (*fptr) (void); |
| 387 | |
| 388 | if (scm_is_string (func)) |
| 389 | func = scm_dynamic_func (func, dobj); |
| 390 | SCM_VALIDATE_POINTER (SCM_ARG1, func); |
| 391 | |
| 392 | fptr = SCM_POINTER_VALUE (func); |
| 393 | fptr (); |
| 394 | return SCM_UNSPECIFIED; |
| 395 | } |
| 396 | #undef FUNC_NAME |
| 397 | |
| 398 | void |
| 399 | scm_init_dynamic_linking () |
| 400 | { |
| 401 | scm_tc16_dynamic_obj = scm_make_smob_type ("dynamic-object", 0); |
| 402 | scm_set_smob_print (scm_tc16_dynamic_obj, dynl_obj_print); |
| 403 | sysdep_dynl_init (); |
| 404 | #include "libguile/dynl.x" |
| 405 | } |
| 406 | |
| 407 | /* |
| 408 | Local Variables: |
| 409 | c-file-style: "gnu" |
| 410 | End: |
| 411 | */ |