gmodule/gmodule.c

   1 /* GMODULE - GLIB wrapper code for dynamic module loading
   2  * Copyright (C) 1998 Tim Janik
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  22  * file for a list of people on the GLib Team.  See the ChangeLog
  23  * files for a list of changes.  These files are distributed with
  24  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  25  */
  26
  27 /*
  28  * MT safe
  29  */
  30
  31 #ifdef HAVE_CONFIG_H
  32 # include <config.h>
  33 #endif
  34 #include        "gstdio.h"
  35 #include        "gmodule.h"
  36 #include        "gmoduleconf.h"
  37 #include        <errno.h>
  38 #include        <string.h>
  39 #include        <sys/types.h>
  40 #include        <sys/stat.h>
  41 #include        <fcntl.h>
  42 #ifdef HAVE_UNISTD_H
  43 # include <unistd.h>
  44 #endif
  45 #if defined (G_OS_WIN32)
  46 # include <io.h>                /* For open() and close() prototypes. */
  47 #endif
  48
  49 /* We maintain a list of modules, so we can reference count them.
  50  * That's needed because some platforms don't support refernce counts on
  51  * modules e.g. the shl_* implementation of HP-UX
  52  * (http://www.stat.umn.edu/~luke/xls/projects/dlbasics/dlbasics.html).
  53  * Also, the module for the program itself is kept seperatedly for
  54  * faster access and because it has special semantics.
  55  */
  56
  57
  58 /* --- structures --- */
  59 struct _GModule
  60 {
  61   gchar *file_name;
  62 #ifdef G_OS_WIN32
  63   gchar *cp_file_name;
  64 #endif
  65   gpointer handle;
  66   guint ref_count : 31;
  67   guint is_resident : 1;
  68   GModuleUnload unload;
  69   GModule *next;
  70 };
  71
  72
  73 /* --- prototypes --- */
  74 static gpointer         _g_module_open          (const gchar    *file_name,
  75                                                  gboolean        bind_lazy,
  76                                                  gboolean        bind_local);
  77 static void             _g_module_close         (gpointer        handle,
  78                                                  gboolean        is_unref);
  79 static gpointer         _g_module_self          (void);
  80 static gpointer         _g_module_symbol        (gpointer        handle,
  81                                                  const gchar    *symbol_name);
  82 static gchar*           _g_module_build_path    (const gchar    *directory,
  83                                                  const gchar    *module_name);
  84 static inline void      g_module_set_error      (const gchar    *error);
  85 static inline GModule*  g_module_find_by_handle (gpointer        handle);
  86 static inline GModule*  g_module_find_by_name   (const gchar    *name);
  87
  88
  89 /* --- variables --- */
  90 static GModule       *modules = NULL;
  91 static GModule       *main_module = NULL;
  92 static GStaticPrivate module_error_private = G_STATIC_PRIVATE_INIT;
  93
  94
  95 /* --- inline functions --- */
  96 static inline GModule*
  97 g_module_find_by_handle (gpointer handle)
  98 {
  99   GModule *module;
 100   GModule *retval = NULL;
 101
 102   if (main_module && main_module->handle == handle)
 103     retval = main_module;
 104   else
 105     for (module = modules; module; module = module->next)
 106       if (handle == module->handle)
 107         {
 108           retval = module;
 109           break;
 110         }
 111
 112   return retval;
 113 }
 114
 115 static inline GModule*
 116 g_module_find_by_name (const gchar *name)
 117 {
 118   GModule *module;
 119   GModule *retval = NULL;
 120
 121   for (module = modules; module; module = module->next)
 122     if (strcmp (name, module->file_name) == 0)
 123         {
 124           retval = module;
 125           break;
 126         }
 127
 128   return retval;
 129 }
 130
 131 static inline void
 132 g_module_set_error_unduped (gchar *error)
 133 {
 134   g_static_private_set (&module_error_private, error, g_free);
 135   errno = 0;
 136 }
 137
 138 static inline void
 139 g_module_set_error (const gchar *error)
 140 {
 141   g_module_set_error_unduped (g_strdup (error));
 142 }
 143
 144
 145 /* --- include platform specifc code --- */
 146 #define SUPPORT_OR_RETURN(rv)   { g_module_set_error (NULL); }
 147 #if     (G_MODULE_IMPL == G_MODULE_IMPL_DL)
 148 #include "gmodule-dl.c"
 149 #elif   (G_MODULE_IMPL == G_MODULE_IMPL_DLD)
 150 #include "gmodule-dld.c"
 151 #elif   (G_MODULE_IMPL == G_MODULE_IMPL_WIN32)
 152 #include "gmodule-win32.c"
 153 #elif   (G_MODULE_IMPL == G_MODULE_IMPL_DYLD)
 154 #include "gmodule-dyld.c"
 155 #elif   (G_MODULE_IMPL == G_MODULE_IMPL_AR)
 156 #include "gmodule-ar.c"
 157 #else
 158 #undef  SUPPORT_OR_RETURN
 159 #define SUPPORT_OR_RETURN(rv)   { g_module_set_error ("dynamic modules are " \
 160                                               "not supported by this system"); return rv; }
 161 static gpointer
 162 _g_module_open (const gchar     *file_name,
 163                 gboolean         bind_lazy,
 164                 gboolean         bind_local)
 165 {
 166   return NULL;
 167 }
 168 static void
 169 _g_module_close (gpointer        handle,
 170                  gboolean        is_unref)
 171 {
 172 }
 173 static gpointer
 174 _g_module_self (void)
 175 {
 176   return NULL;
 177 }
 178 static gpointer
 179 _g_module_symbol (gpointer       handle,
 180                   const gchar   *symbol_name)
 181 {
 182   return NULL;
 183 }
 184 static gchar*
 185 _g_module_build_path (const gchar *directory,
 186                       const gchar *module_name)
 187 {
 188   return NULL;
 189 }
 190 #endif  /* no implementation */
 191
 192 /* --- functions --- */
 193 gboolean
 194 g_module_supported (void)
 195 {
 196   SUPPORT_OR_RETURN (FALSE);
 197
 198   return TRUE;
 199 }
 200
 201 static gchar*
 202 parse_libtool_archive (const gchar* libtool_name)
 203 {
 204   const guint TOKEN_DLNAME = G_TOKEN_LAST + 1;
 205   const guint TOKEN_INSTALLED = G_TOKEN_LAST + 2;
 206   const guint TOKEN_LIBDIR = G_TOKEN_LAST + 3;
 207   gchar *lt_dlname = NULL;
 208   gboolean lt_installed = TRUE;
 209   gchar *lt_libdir = NULL;
 210   gchar *name;
 211   GTokenType token;
 212   GScanner *scanner;
 213
 214   int fd = g_open (libtool_name, O_RDONLY, 0);
 215   if (fd < 0)
 216     {
 217       gchar *display_libtool_name = g_filename_display_name (libtool_name);
 218       g_module_set_error_unduped (g_strdup_printf ("failed to open libtool archive \"%s\"", display_libtool_name));
 219       g_free (display_libtool_name);
 220       return NULL;
 221     }
 222   /* search libtool's dlname specification  */
 223   scanner = g_scanner_new (NULL);
 224   g_scanner_input_file (scanner, fd);
 225   scanner->config->symbol_2_token = TRUE;
 226   g_scanner_scope_add_symbol (scanner, 0, "dlname",
 227                               GUINT_TO_POINTER (TOKEN_DLNAME));
 228   g_scanner_scope_add_symbol (scanner, 0, "installed",
 229                               GUINT_TO_POINTER (TOKEN_INSTALLED));
 230   g_scanner_scope_add_symbol (scanner, 0, "libdir",
 231                               GUINT_TO_POINTER (TOKEN_LIBDIR));
 232   while (!g_scanner_eof (scanner))
 233     {
 234       token = g_scanner_get_next_token (scanner);
 235       if (token == TOKEN_DLNAME || token == TOKEN_INSTALLED ||
 236           token == TOKEN_LIBDIR)
 237         {
 238           if (g_scanner_get_next_token (scanner) != '=' ||
 239               g_scanner_get_next_token (scanner) !=
 240               (token == TOKEN_INSTALLED ?
 241                G_TOKEN_IDENTIFIER : G_TOKEN_STRING))
 242             {
 243               gchar *display_libtool_name = g_filename_display_name (libtool_name);
 244               g_module_set_error_unduped (g_strdup_printf ("unable to parse libtool archive \"%s\"", display_libtool_name));
 245               g_free (display_libtool_name);
 246
 247               g_free (lt_dlname);
 248               g_free (lt_libdir);
 249               g_scanner_destroy (scanner);
 250               close (fd);
 251
 252               return NULL;
 253             }
 254           else
 255             {
 256               if (token == TOKEN_DLNAME)
 257                 {
 258                   g_free (lt_dlname);
 259                   lt_dlname = g_strdup (scanner->value.v_string);
 260                 }
 261               else if (token == TOKEN_INSTALLED)
 262                 lt_installed =
 263                   strcmp (scanner->value.v_identifier, "yes") == 0;
 264               else /* token == TOKEN_LIBDIR */
 265                 {
 266                   g_free (lt_libdir);
 267                   lt_libdir = g_strdup (scanner->value.v_string);
 268                 }
 269             }
 270         }
 271     }
 272
 273   if (!lt_installed)
 274     {
 275       gchar *dir = g_path_get_dirname (libtool_name);
 276       g_free (lt_libdir);
 277       lt_libdir = g_strconcat (dir, G_DIR_SEPARATOR_S ".libs", NULL);
 278       g_free (dir);
 279     }
 280
 281   name = g_strconcat (lt_libdir, G_DIR_SEPARATOR_S, lt_dlname, NULL);
 282
 283   g_free (lt_dlname);
 284   g_free (lt_libdir);
 285   g_scanner_destroy (scanner);
 286   close (fd);
 287
 288   return name;
 289 }
 290
 291 static inline gboolean
 292 str_check_suffix (const gchar* string,
 293                   const gchar* suffix)
 294 {
 295   gsize string_len = strlen (string);
 296   gsize suffix_len = strlen (suffix);
 297
 298   return string_len >= suffix_len &&
 299     strcmp (string + string_len - suffix_len, suffix) == 0;
 300 }
 301
 302 static GStaticRecMutex g_module_global_lock = G_STATIC_REC_MUTEX_INIT;
 303
 304 GModule*
 305 g_module_open (const gchar    *file_name,
 306                GModuleFlags    flags)
 307 {
 308   GModule *module;
 309   gpointer handle = NULL;
 310   gchar *name = NULL;
 311
 312   SUPPORT_OR_RETURN (NULL);
 313
 314   g_static_rec_mutex_lock (&g_module_global_lock);
 315   if (!file_name)
 316     {
 317       if (!main_module)
 318         {
 319           handle = _g_module_self ();
 320           if (handle)
 321             {
 322               main_module = g_new (GModule, 1);
 323               main_module->file_name = NULL;
 324 #ifdef G_OS_WIN32
 325               main_module->cp_file_name = NULL;
 326 #endif
 327               main_module->handle = handle;
 328               main_module->ref_count = 1;
 329               main_module->is_resident = TRUE;
 330               main_module->unload = NULL;
 331               main_module->next = NULL;
 332             }
 333         }
 334       else
 335         main_module->ref_count++;
 336
 337       g_static_rec_mutex_unlock (&g_module_global_lock);
 338       return main_module;
 339     }
 340
 341   /* we first search the module list by name */
 342   module = g_module_find_by_name (file_name);
 343   if (module)
 344     {
 345       module->ref_count++;
 346
 347       g_static_rec_mutex_unlock (&g_module_global_lock);
 348       return module;
 349     }
 350
 351   /* check whether we have a readable file right away */
 352   if (g_file_test (file_name, G_FILE_TEST_IS_REGULAR))
 353     name = g_strdup (file_name);
 354   /* try completing file name with standard library suffix */
 355   if (!name)
 356     {
 357       name = g_strconcat (file_name, "." G_MODULE_SUFFIX, NULL);
 358       if (!g_file_test (name, G_FILE_TEST_IS_REGULAR))
 359         {
 360           g_free (name);
 361           name = NULL;
 362         }
 363     }
 364   /* try completing by appending libtool suffix */
 365   if (!name)
 366     {
 367       name = g_strconcat (file_name, ".la", NULL);
 368       if (!g_file_test (name, G_FILE_TEST_IS_REGULAR))
 369         {
 370           g_free (name);
 371           name = NULL;
 372         }
 373     }
 374   /* we can't access() the file, lets hope the platform backends finds
 375    * it via library paths
 376    */
 377   if (!name)
 378     {
 379       gchar *dot = strrchr (file_name, '.');
 380       gchar *slash = strrchr (file_name, G_DIR_SEPARATOR);
 381
 382       /* make sure the name has a suffix */
 383       if (!dot || dot < slash)
 384         name = g_strconcat (file_name, "." G_MODULE_SUFFIX, NULL);
 385       else
 386         name = g_strdup (file_name);
 387     }
 388
 389   /* ok, try loading the module */
 390   if (name)
 391     {
 392       /* if it's a libtool archive, figure library file to load */
 393       if (str_check_suffix (name, ".la")) /* libtool archive? */
 394         {
 395           gchar *real_name = parse_libtool_archive (name);
 396
 397           /* real_name might be NULL, but then module error is already set */
 398           g_free (name);
 399           name = real_name;
 400         }
 401       if (name)
 402         handle = _g_module_open (name, (flags & G_MODULE_BIND_LAZY) != 0,
 403                         (flags & G_MODULE_BIND_LOCAL) != 0);
 404     }
 405   else
 406     {
 407       gchar *display_file_name = g_filename_display_name (file_name);
 408       g_module_set_error_unduped (g_strdup_printf ("unable to access file \"%s\"", display_file_name));
 409       g_free (display_file_name);
 410     }
 411   g_free (name);
 412
 413   if (handle)
 414     {
 415       gchar *saved_error;
 416       GModuleCheckInit check_init;
 417       const gchar *check_failed = NULL;
 418
 419       /* search the module list by handle, since file names are not unique */
 420       module = g_module_find_by_handle (handle);
 421       if (module)
 422         {
 423           _g_module_close (module->handle, TRUE);
 424           module->ref_count++;
 425           g_module_set_error (NULL);
 426
 427           g_static_rec_mutex_unlock (&g_module_global_lock);
 428           return module;
 429         }
 430
 431       saved_error = g_strdup (g_module_error ());
 432       g_module_set_error (NULL);
 433
 434       module = g_new (GModule, 1);
 435       module->file_name = g_strdup (file_name);
 436 #ifdef G_OS_WIN32
 437       module->cp_file_name = g_locale_from_utf8 (file_name, -1,
 438                                                  NULL, NULL, NULL);
 439 #endif
 440       module->handle = handle;
 441       module->ref_count = 1;
 442       module->is_resident = FALSE;
 443       module->unload = NULL;
 444       module->next = modules;
 445       modules = module;
 446
 447       /* check initialization */
 448       if (g_module_symbol (module, "g_module_check_init", (gpointer) &check_init))
 449         check_failed = check_init (module);
 450
 451       /* we don't call unload() if the initialization check failed. */
 452       if (!check_failed)
 453         g_module_symbol (module, "g_module_unload", (gpointer) &module->unload);
 454
 455       if (check_failed)
 456         {
 457           gchar *error;
 458
 459           error = g_strconcat ("GModule initialization check failed: ", check_failed, NULL);
 460           g_module_close (module);
 461           module = NULL;
 462           g_module_set_error (error);
 463           g_free (error);
 464         }
 465       else
 466         g_module_set_error (saved_error);
 467
 468       g_free (saved_error);
 469     }
 470
 471   g_static_rec_mutex_unlock (&g_module_global_lock);
 472   return module;
 473 }
 474
 475 #ifdef G_OS_WIN32
 476
 477 #undef g_module_open
 478
 479 GModule*
 480 g_module_open (const gchar    *file_name,
 481                GModuleFlags    flags)
 482 {
 483   gchar *utf8_file_name = g_locale_to_utf8 (file_name, -1, NULL, NULL, NULL);
 484   GModule *retval = g_module_open_utf8 (utf8_file_name, flags);
 485
 486   g_free (utf8_file_name);
 487
 488   return retval;
 489 }
 490
 491 #endif
 492
 493 gboolean
 494 g_module_close (GModule        *module)
 495 {
 496   SUPPORT_OR_RETURN (FALSE);
 497
 498   g_return_val_if_fail (module != NULL, FALSE);
 499   g_return_val_if_fail (module->ref_count > 0, FALSE);
 500
 501   g_static_rec_mutex_lock (&g_module_global_lock);
 502
 503   module->ref_count--;
 504
 505   if (!module->ref_count && !module->is_resident && module->unload)
 506     {
 507       GModuleUnload unload;
 508
 509       unload = module->unload;
 510       module->unload = NULL;
 511       unload (module);
 512     }
 513
 514   if (!module->ref_count && !module->is_resident)
 515     {
 516       GModule *last;
 517       GModule *node;
 518
 519       last = NULL;
 520
 521       node = modules;
 522       while (node)
 523         {
 524           if (node == module)
 525             {
 526               if (last)
 527                 last->next = node->next;
 528               else
 529                 modules = node->next;
 530               break;
 531             }
 532           last = node;
 533           node = last->next;
 534         }
 535       module->next = NULL;
 536
 537       _g_module_close (module->handle, FALSE);
 538       g_free (module->file_name);
 539 #ifdef G_OS_WIN32
 540       g_free (module->cp_file_name);
 541 #endif
 542       g_free (module);
 543     }
 544
 545   g_static_rec_mutex_unlock (&g_module_global_lock);
 546   return g_module_error() == NULL;
 547 }
 548
 549 void
 550 g_module_make_resident (GModule *module)
 551 {
 552   g_return_if_fail (module != NULL);
 553
 554   module->is_resident = TRUE;
 555 }
 556
 557 G_CONST_RETURN gchar*
 558 g_module_error (void)
 559 {
 560   return g_static_private_get (&module_error_private);
 561 }
 562
 563 gboolean
 564 g_module_symbol (GModule        *module,
 565                  const gchar    *symbol_name,
 566                  gpointer       *symbol)
 567 {
 568   const gchar *module_error;
 569
 570   if (symbol)
 571     *symbol = NULL;
 572   SUPPORT_OR_RETURN (FALSE);
 573
 574   g_return_val_if_fail (module != NULL, FALSE);
 575   g_return_val_if_fail (symbol_name != NULL, FALSE);
 576   g_return_val_if_fail (symbol != NULL, FALSE);
 577
 578   g_static_rec_mutex_lock (&g_module_global_lock);
 579
 580 #ifdef  G_MODULE_NEED_USCORE
 581   {
 582     gchar *name;
 583
 584     name = g_strconcat ("_", symbol_name, NULL);
 585     *symbol = _g_module_symbol (module->handle, name);
 586     g_free (name);
 587   }
 588 #else   /* !G_MODULE_NEED_USCORE */
 589   *symbol = _g_module_symbol (module->handle, symbol_name);
 590 #endif  /* !G_MODULE_NEED_USCORE */
 591
 592   module_error = g_module_error ();
 593   if (module_error)
 594     {
 595       gchar *error;
 596
 597       error = g_strconcat ("`", symbol_name, "': ", module_error, NULL);
 598       g_module_set_error (error);
 599       g_free (error);
 600       *symbol = NULL;
 601     }
 602
 603   g_static_rec_mutex_unlock (&g_module_global_lock);
 604   return !module_error;
 605 }
 606
 607 G_CONST_RETURN gchar*
 608 g_module_name (GModule *module)
 609 {
 610   g_return_val_if_fail (module != NULL, NULL);
 611
 612   if (module == main_module)
 613     return "main";
 614
 615   return module->file_name;
 616 }
 617
 618 #ifdef G_OS_WIN32
 619
 620 #undef g_module_name
 621
 622 G_CONST_RETURN gchar*
 623 g_module_name (GModule *module)
 624 {
 625   g_return_val_if_fail (module != NULL, NULL);
 626
 627   if (module == main_module)
 628     return "main";
 629
 630   return module->cp_file_name;
 631 }
 632
 633 #endif
 634
 635 gchar*
 636 g_module_build_path (const gchar *directory,
 637                      const gchar *module_name)
 638 {
 639   g_return_val_if_fail (module_name != NULL, NULL);
 640
 641   return _g_module_build_path (directory, module_name);
 642 }