bfd/plugin.c

   1 /* Plugin support for BFD.
   2    Copyright (C) 2009-2017 Free Software Foundation, Inc.
   3
   4    This file is part of BFD, the Binary File Descriptor library.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 #include "sysdep.h"
  22 #include "bfd.h"
  23
  24 #if BFD_SUPPORTS_PLUGINS
  25
  26 #include <assert.h>
  27 #ifdef HAVE_DLFCN_H
  28 #include <dlfcn.h>
  29 #elif defined (HAVE_WINDOWS_H)
  30 #include <windows.h>
  31 #else
  32 #error Unknown how to handle dynamic-load-libraries.
  33 #endif
  34 #include <stdarg.h>
  35 #include "plugin-api.h"
  36 #include "plugin.h"
  37 #include "libbfd.h"
  38 #include "libiberty.h"
  39 #include <dirent.h>
  40
  41 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
  42
  43 #define RTLD_NOW 0      /* Dummy value.  */
  44
  45 static void *
  46 dlopen (const char *file, int mode ATTRIBUTE_UNUSED)
  47 {
  48   return LoadLibrary (file);
  49 }
  50
  51 static void *
  52 dlsym (void *handle, const char *name)
  53 {
  54   return GetProcAddress (handle, name);
  55 }
  56
  57 static int ATTRIBUTE_UNUSED
  58 dlclose (void *handle)
  59 {
  60   FreeLibrary (handle);
  61   return 0;
  62 }
  63
  64 static const char *
  65 dlerror (void)
  66 {
  67   return "Unable to load DLL.";
  68 }
  69
  70 #endif /* !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)  */
  71
  72 #define bfd_plugin_close_and_cleanup                  _bfd_generic_close_and_cleanup
  73 #define bfd_plugin_bfd_free_cached_info               _bfd_generic_bfd_free_cached_info
  74 #define bfd_plugin_new_section_hook                   _bfd_generic_new_section_hook
  75 #define bfd_plugin_get_section_contents               _bfd_generic_get_section_contents
  76 #define bfd_plugin_get_section_contents_in_window     _bfd_generic_get_section_contents_in_window
  77 #define bfd_plugin_bfd_copy_private_header_data       _bfd_generic_bfd_copy_private_header_data
  78 #define bfd_plugin_bfd_merge_private_bfd_data         _bfd_generic_bfd_merge_private_bfd_data
  79 #define bfd_plugin_bfd_copy_private_header_data       _bfd_generic_bfd_copy_private_header_data
  80 #define bfd_plugin_bfd_set_private_flags              _bfd_generic_bfd_set_private_flags
  81 #define bfd_plugin_core_file_matches_executable_p     generic_core_file_matches_executable_p
  82 #define bfd_plugin_bfd_is_local_label_name            _bfd_nosymbols_bfd_is_local_label_name
  83 #define bfd_plugin_bfd_is_target_special_symbol       ((bfd_boolean (*) (bfd *, asymbol *)) bfd_false)
  84 #define bfd_plugin_get_lineno                         _bfd_nosymbols_get_lineno
  85 #define bfd_plugin_find_nearest_line                  _bfd_nosymbols_find_nearest_line
  86 #define bfd_plugin_find_line                          _bfd_nosymbols_find_line
  87 #define bfd_plugin_find_inliner_info                  _bfd_nosymbols_find_inliner_info
  88 #define bfd_plugin_get_symbol_version_string          _bfd_nosymbols_get_symbol_version_string
  89 #define bfd_plugin_bfd_make_debug_symbol              _bfd_nosymbols_bfd_make_debug_symbol
  90 #define bfd_plugin_read_minisymbols                   _bfd_generic_read_minisymbols
  91 #define bfd_plugin_minisymbol_to_symbol               _bfd_generic_minisymbol_to_symbol
  92 #define bfd_plugin_set_arch_mach                      bfd_default_set_arch_mach
  93 #define bfd_plugin_set_section_contents               _bfd_generic_set_section_contents
  94 #define bfd_plugin_bfd_get_relocated_section_contents bfd_generic_get_relocated_section_contents
  95 #define bfd_plugin_bfd_relax_section                  bfd_generic_relax_section
  96 #define bfd_plugin_bfd_link_hash_table_create         _bfd_generic_link_hash_table_create
  97 #define bfd_plugin_bfd_link_add_symbols               _bfd_generic_link_add_symbols
  98 #define bfd_plugin_bfd_link_just_syms                 _bfd_generic_link_just_syms
  99 #define bfd_plugin_bfd_final_link                     _bfd_generic_final_link
 100 #define bfd_plugin_bfd_link_split_section             _bfd_generic_link_split_section
 101 #define bfd_plugin_bfd_gc_sections                    bfd_generic_gc_sections
 102 #define bfd_plugin_bfd_lookup_section_flags           bfd_generic_lookup_section_flags
 103 #define bfd_plugin_bfd_merge_sections                 bfd_generic_merge_sections
 104 #define bfd_plugin_bfd_is_group_section               bfd_generic_is_group_section
 105 #define bfd_plugin_bfd_discard_group                  bfd_generic_discard_group
 106 #define bfd_plugin_section_already_linked             _bfd_generic_section_already_linked
 107 #define bfd_plugin_bfd_define_common_symbol           bfd_generic_define_common_symbol
 108 #define bfd_plugin_bfd_define_start_stop              bfd_generic_define_start_stop
 109 #define bfd_plugin_bfd_copy_link_hash_symbol_type     _bfd_generic_copy_link_hash_symbol_type
 110 #define bfd_plugin_bfd_link_check_relocs              _bfd_generic_link_check_relocs
 111
 112 static enum ld_plugin_status
 113 message (int level ATTRIBUTE_UNUSED,
 114          const char * format, ...)
 115 {
 116   va_list args;
 117   va_start (args, format);
 118   printf ("bfd plugin: ");
 119   vprintf (format, args);
 120   putchar ('\n');
 121   va_end (args);
 122   return LDPS_OK;
 123 }
 124
 125 /* Register a claim-file handler. */
 126 static ld_plugin_claim_file_handler claim_file;
 127
 128 static enum ld_plugin_status
 129 register_claim_file (ld_plugin_claim_file_handler handler)
 130 {
 131   claim_file = handler;
 132   return LDPS_OK;
 133 }
 134
 135 static enum ld_plugin_status
 136 add_symbols (void * handle,
 137              int nsyms,
 138              const struct ld_plugin_symbol * syms)
 139 {
 140   bfd *abfd = handle;
 141   struct plugin_data_struct *plugin_data =
 142     bfd_alloc (abfd, sizeof (plugin_data_struct));
 143
 144   plugin_data->nsyms = nsyms;
 145   plugin_data->syms = syms;
 146
 147   if (nsyms != 0)
 148     abfd->flags |= HAS_SYMS;
 149
 150   abfd->tdata.plugin_data = plugin_data;
 151   return LDPS_OK;
 152 }
 153
 154 static const char *plugin_program_name;
 155
 156 void
 157 bfd_plugin_set_program_name (const char *program_name)
 158 {
 159   plugin_program_name = program_name;
 160 }
 161
 162 int
 163 bfd_plugin_open_input (bfd *ibfd, struct ld_plugin_input_file *file)
 164 {
 165   bfd *iobfd;
 166
 167   iobfd = ibfd;
 168   if (ibfd->my_archive && !bfd_is_thin_archive (ibfd->my_archive))
 169     iobfd = ibfd->my_archive;
 170   file->name = iobfd->filename;
 171
 172   if (!iobfd->iostream && !bfd_open_file (iobfd))
 173     return 0;
 174
 175   file->fd = fileno ((FILE *) iobfd->iostream);
 176
 177   if (iobfd == ibfd)
 178     {
 179       struct stat stat_buf;
 180       if (fstat (file->fd, &stat_buf))
 181         return 0;
 182       file->offset = 0;
 183       file->filesize = stat_buf.st_size;
 184     }
 185   else
 186     {
 187       file->offset = ibfd->origin;
 188       file->filesize = arelt_size (ibfd);
 189     }
 190   return 1;
 191 }
 192
 193 static int
 194 try_claim (bfd *abfd)
 195 {
 196   int claimed = 0;
 197   struct ld_plugin_input_file file;
 198
 199   if (!bfd_plugin_open_input (abfd, &file))
 200     return 0;
 201   file.handle = abfd;
 202   off_t cur_offset = lseek (file.fd, 0, SEEK_CUR);
 203   claim_file (&file, &claimed);
 204   lseek (file.fd, cur_offset, SEEK_SET);
 205   return claimed;
 206 }
 207
 208 static int
 209 try_load_plugin (const char *pname, bfd *abfd, int *has_plugin_p)
 210 {
 211   void *plugin_handle;
 212   struct ld_plugin_tv tv[4];
 213   int i;
 214   ld_plugin_onload onload;
 215   enum ld_plugin_status status;
 216
 217   *has_plugin_p = 0;
 218
 219   plugin_handle = dlopen (pname, RTLD_NOW);
 220   if (!plugin_handle)
 221     {
 222       _bfd_error_handler ("%s\n", dlerror ());
 223       return 0;
 224     }
 225
 226   onload = dlsym (plugin_handle, "onload");
 227   if (!onload)
 228     goto err;
 229
 230   i = 0;
 231   tv[i].tv_tag = LDPT_MESSAGE;
 232   tv[i].tv_u.tv_message = message;
 233
 234   ++i;
 235   tv[i].tv_tag = LDPT_REGISTER_CLAIM_FILE_HOOK;
 236   tv[i].tv_u.tv_register_claim_file = register_claim_file;
 237
 238   ++i;
 239   tv[i].tv_tag = LDPT_ADD_SYMBOLS;
 240   tv[i].tv_u.tv_add_symbols = add_symbols;
 241
 242   ++i;
 243   tv[i].tv_tag = LDPT_NULL;
 244   tv[i].tv_u.tv_val = 0;
 245
 246   status = (*onload)(tv);
 247
 248   if (status != LDPS_OK)
 249     goto err;
 250
 251   *has_plugin_p = 1;
 252
 253   abfd->plugin_format = bfd_plugin_no;
 254
 255   if (!claim_file)
 256     goto err;
 257
 258   if (!try_claim (abfd))
 259     goto err;
 260
 261   abfd->plugin_format = bfd_plugin_yes;
 262
 263   return 1;
 264
 265  err:
 266   return 0;
 267 }
 268
 269 /* There may be plugin libraries in lib/bfd-plugins.  */
 270
 271 static int has_plugin = -1;
 272
 273 static const bfd_target *(*ld_plugin_object_p) (bfd *);
 274
 275 static const char *plugin_name;
 276
 277 void
 278 bfd_plugin_set_plugin (const char *p)
 279 {
 280   plugin_name = p;
 281   has_plugin = p != NULL;
 282 }
 283
 284 /* Return TRUE if a plugin library is used.  */
 285
 286 bfd_boolean
 287 bfd_plugin_specified_p (void)
 288 {
 289   return has_plugin > 0;
 290 }
 291
 292 /* Return TRUE if ABFD can be claimed by linker LTO plugin.  */
 293
 294 bfd_boolean
 295 bfd_link_plugin_object_p (bfd *abfd)
 296 {
 297   if (ld_plugin_object_p)
 298     return ld_plugin_object_p (abfd) != NULL;
 299   return FALSE;
 300 }
 301
 302 extern const bfd_target plugin_vec;
 303
 304 /* Return TRUE if TARGET is a pointer to plugin_vec.  */
 305
 306 bfd_boolean
 307 bfd_plugin_target_p (const bfd_target *target)
 308 {
 309   return target == &plugin_vec;
 310 }
 311
 312 /* Register OBJECT_P to be used by bfd_plugin_object_p.  */
 313
 314 void
 315 register_ld_plugin_object_p (const bfd_target *(*object_p) (bfd *))
 316 {
 317   ld_plugin_object_p = object_p;
 318 }
 319
 320 static int
 321 load_plugin (bfd *abfd)
 322 {
 323   char *plugin_dir;
 324   char *p;
 325   DIR *d;
 326   struct dirent *ent;
 327   int found = 0;
 328
 329   if (!has_plugin)
 330     return found;
 331
 332   if (plugin_name)
 333     return try_load_plugin (plugin_name, abfd, &has_plugin);
 334
 335   if (plugin_program_name == NULL)
 336     return found;
 337
 338   plugin_dir = concat (BINDIR, "/../lib/bfd-plugins", NULL);
 339   p = make_relative_prefix (plugin_program_name,
 340                             BINDIR,
 341                             plugin_dir);
 342   free (plugin_dir);
 343   plugin_dir = NULL;
 344
 345   d = opendir (p);
 346   if (!d)
 347     goto out;
 348
 349   while ((ent = readdir (d)))
 350     {
 351       char *full_name;
 352       struct stat s;
 353       int valid_plugin;
 354
 355       full_name = concat (p, "/", ent->d_name, NULL);
 356       if (stat(full_name, &s) == 0 && S_ISREG (s.st_mode))
 357         found = try_load_plugin (full_name, abfd, &valid_plugin);
 358       if (has_plugin <= 0)
 359         has_plugin = valid_plugin;
 360       free (full_name);
 361       if (found)
 362         break;
 363     }
 364
 365  out:
 366   free (p);
 367   if (d)
 368     closedir (d);
 369
 370   return found;
 371 }
 372
 373
 374 static const bfd_target *
 375 bfd_plugin_object_p (bfd *abfd)
 376 {
 377   if (ld_plugin_object_p)
 378     return ld_plugin_object_p (abfd);
 379
 380   if (abfd->plugin_format == bfd_plugin_unknown && !load_plugin (abfd))
 381     return NULL;
 382
 383   return abfd->plugin_format == bfd_plugin_yes ? abfd->xvec : NULL;
 384 }
 385
 386 /* Copy any private info we understand from the input bfd
 387    to the output bfd.  */
 388
 389 static bfd_boolean
 390 bfd_plugin_bfd_copy_private_bfd_data (bfd *ibfd ATTRIBUTE_UNUSED,
 391                                       bfd *obfd ATTRIBUTE_UNUSED)
 392 {
 393   BFD_ASSERT (0);
 394   return TRUE;
 395 }
 396
 397 /* Copy any private info we understand from the input section
 398    to the output section.  */
 399
 400 static bfd_boolean
 401 bfd_plugin_bfd_copy_private_section_data (bfd *ibfd ATTRIBUTE_UNUSED,
 402                                           asection *isection ATTRIBUTE_UNUSED,
 403                                           bfd *obfd ATTRIBUTE_UNUSED,
 404                                           asection *osection ATTRIBUTE_UNUSED)
 405 {
 406   BFD_ASSERT (0);
 407   return TRUE;
 408 }
 409
 410 /* Copy any private info we understand from the input symbol
 411    to the output symbol.  */
 412
 413 static bfd_boolean
 414 bfd_plugin_bfd_copy_private_symbol_data (bfd *ibfd ATTRIBUTE_UNUSED,
 415                                          asymbol *isymbol ATTRIBUTE_UNUSED,
 416                                          bfd *obfd ATTRIBUTE_UNUSED,
 417                                          asymbol *osymbol ATTRIBUTE_UNUSED)
 418 {
 419   BFD_ASSERT (0);
 420   return TRUE;
 421 }
 422
 423 static bfd_boolean
 424 bfd_plugin_bfd_print_private_bfd_data (bfd *abfd ATTRIBUTE_UNUSED, PTR ptr ATTRIBUTE_UNUSED)
 425 {
 426   BFD_ASSERT (0);
 427   return TRUE;
 428 }
 429
 430 static char *
 431 bfd_plugin_core_file_failing_command (bfd *abfd ATTRIBUTE_UNUSED)
 432 {
 433   BFD_ASSERT (0);
 434   return NULL;
 435 }
 436
 437 static int
 438 bfd_plugin_core_file_failing_signal (bfd *abfd ATTRIBUTE_UNUSED)
 439 {
 440   BFD_ASSERT (0);
 441   return 0;
 442 }
 443
 444 static int
 445 bfd_plugin_core_file_pid (bfd *abfd ATTRIBUTE_UNUSED)
 446 {
 447   BFD_ASSERT (0);
 448   return 0;
 449 }
 450
 451 static long
 452 bfd_plugin_get_symtab_upper_bound (bfd *abfd)
 453 {
 454   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
 455   long nsyms = plugin_data->nsyms;
 456
 457   BFD_ASSERT (nsyms >= 0);
 458
 459   return ((nsyms + 1) * sizeof (asymbol *));
 460 }
 461
 462 static flagword
 463 convert_flags (const struct ld_plugin_symbol *sym)
 464 {
 465  switch (sym->def)
 466    {
 467    case LDPK_DEF:
 468    case LDPK_COMMON:
 469    case LDPK_UNDEF:
 470      return BSF_GLOBAL;
 471
 472    case LDPK_WEAKUNDEF:
 473    case LDPK_WEAKDEF:
 474      return BSF_GLOBAL | BSF_WEAK;
 475
 476    default:
 477      BFD_ASSERT (0);
 478      return 0;
 479    }
 480 }
 481
 482 static long
 483 bfd_plugin_canonicalize_symtab (bfd *abfd,
 484                                 asymbol **alocation)
 485 {
 486   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
 487   long nsyms = plugin_data->nsyms;
 488   const struct ld_plugin_symbol *syms = plugin_data->syms;
 489   static asection fake_section;
 490   static asection fake_common_section;
 491   int i;
 492
 493   fake_section.name = ".text";
 494   fake_common_section.flags = SEC_IS_COMMON;
 495
 496   for (i = 0; i < nsyms; i++)
 497     {
 498       asymbol *s = bfd_alloc (abfd, sizeof (asymbol));
 499
 500       BFD_ASSERT (s);
 501       alocation[i] = s;
 502
 503       s->the_bfd = abfd;
 504       s->name = syms[i].name;
 505       s->value = 0;
 506       s->flags = convert_flags (&syms[i]);
 507       switch (syms[i].def)
 508         {
 509         case LDPK_COMMON:
 510           s->section = &fake_common_section;
 511           break;
 512         case LDPK_UNDEF:
 513         case LDPK_WEAKUNDEF:
 514           s->section = bfd_und_section_ptr;
 515           break;
 516         case LDPK_DEF:
 517         case LDPK_WEAKDEF:
 518           s->section = &fake_section;
 519           break;
 520         default:
 521           BFD_ASSERT (0);
 522         }
 523
 524       s->udata.p = (void *) &syms[i];
 525     }
 526
 527   return nsyms;
 528 }
 529
 530 static void
 531 bfd_plugin_print_symbol (bfd *abfd ATTRIBUTE_UNUSED,
 532                          PTR afile ATTRIBUTE_UNUSED,
 533                          asymbol *symbol ATTRIBUTE_UNUSED,
 534                          bfd_print_symbol_type how ATTRIBUTE_UNUSED)
 535 {
 536   BFD_ASSERT (0);
 537 }
 538
 539 static void
 540 bfd_plugin_get_symbol_info (bfd *abfd ATTRIBUTE_UNUSED,
 541                             asymbol *symbol,
 542                             symbol_info *ret)
 543 {
 544   bfd_symbol_info (symbol, ret);
 545 }
 546
 547 /* Make an empty symbol. */
 548
 549 static asymbol *
 550 bfd_plugin_make_empty_symbol (bfd *abfd)
 551 {
 552   asymbol *new_symbol = bfd_zalloc (abfd, sizeof (asymbol));
 553   if (new_symbol == NULL)
 554     return new_symbol;
 555   new_symbol->the_bfd = abfd;
 556   return new_symbol;
 557 }
 558
 559 static int
 560 bfd_plugin_sizeof_headers (bfd *a ATTRIBUTE_UNUSED,
 561                            struct bfd_link_info *info ATTRIBUTE_UNUSED)
 562 {
 563   BFD_ASSERT (0);
 564   return 0;
 565 }
 566
 567 const bfd_target plugin_vec =
 568 {
 569   "plugin",                     /* Name.  */
 570   bfd_target_unknown_flavour,
 571   BFD_ENDIAN_LITTLE,            /* Target byte order.  */
 572   BFD_ENDIAN_LITTLE,            /* Target headers byte order.  */
 573   (HAS_RELOC | EXEC_P |         /* Object flags.  */
 574    HAS_LINENO | HAS_DEBUG |
 575    HAS_SYMS | HAS_LOCALS | DYNAMIC | WP_TEXT | D_PAGED),
 576   (SEC_CODE | SEC_DATA | SEC_ROM | SEC_HAS_CONTENTS
 577    | SEC_ALLOC | SEC_LOAD | SEC_RELOC), /* Section flags.  */
 578   0,                            /* symbol_leading_char.  */
 579   '/',                          /* ar_pad_char.  */
 580   15,                           /* ar_max_namelen.  */
 581   255,                          /* match priority.  */
 582
 583   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 584   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 585   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* data */
 586   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 587   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 588   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* hdrs */
 589
 590   {                             /* bfd_check_format.  */
 591     _bfd_dummy_target,
 592     bfd_plugin_object_p,
 593     bfd_generic_archive_p,
 594     _bfd_dummy_target
 595   },
 596   {                             /* bfd_set_format.  */
 597     bfd_false,
 598     bfd_false,
 599     _bfd_generic_mkarchive,
 600     bfd_false,
 601   },
 602   {                             /* bfd_write_contents.  */
 603     bfd_false,
 604     bfd_false,
 605     _bfd_write_archive_contents,
 606     bfd_false,
 607   },
 608
 609   BFD_JUMP_TABLE_GENERIC (bfd_plugin),
 610   BFD_JUMP_TABLE_COPY (bfd_plugin),
 611   BFD_JUMP_TABLE_CORE (bfd_plugin),
 612 #ifdef USE_64_BIT_ARCHIVE
 613   BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_64_bit),
 614 #else
 615   BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
 616 #endif
 617   BFD_JUMP_TABLE_SYMBOLS (bfd_plugin),
 618   BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
 619   BFD_JUMP_TABLE_WRITE (bfd_plugin),
 620   BFD_JUMP_TABLE_LINK (bfd_plugin),
 621   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 622
 623   NULL,
 624
 625   NULL                          /* backend_data.  */
 626 };
 627 #endif /* BFD_SUPPORTS_PLUGIN */