bfd/plugin.c

   1 /* Plugin support for BFD.
   2    Copyright (C) 2009-2018 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_bool_bfd_asymbol_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_link_hide_symbol               _bfd_generic_link_hide_symbol
 109 #define bfd_plugin_bfd_define_start_stop              bfd_generic_define_start_stop
 110 #define bfd_plugin_bfd_copy_link_hash_symbol_type     _bfd_generic_copy_link_hash_symbol_type
 111 #define bfd_plugin_bfd_link_check_relocs              _bfd_generic_link_check_relocs
 112
 113 static enum ld_plugin_status
 114 message (int level ATTRIBUTE_UNUSED,
 115          const char * format, ...)
 116 {
 117   va_list args;
 118   va_start (args, format);
 119   printf ("bfd plugin: ");
 120   vprintf (format, args);
 121   putchar ('\n');
 122   va_end (args);
 123   return LDPS_OK;
 124 }
 125
 126 /* Register a claim-file handler. */
 127 static ld_plugin_claim_file_handler claim_file;
 128
 129 static enum ld_plugin_status
 130 register_claim_file (ld_plugin_claim_file_handler handler)
 131 {
 132   claim_file = handler;
 133   return LDPS_OK;
 134 }
 135
 136 static enum ld_plugin_status
 137 add_symbols (void * handle,
 138              int nsyms,
 139              const struct ld_plugin_symbol * syms)
 140 {
 141   bfd *abfd = handle;
 142   struct plugin_data_struct *plugin_data =
 143     bfd_alloc (abfd, sizeof (plugin_data_struct));
 144
 145   plugin_data->nsyms = nsyms;
 146   plugin_data->syms = syms;
 147
 148   if (nsyms != 0)
 149     abfd->flags |= HAS_SYMS;
 150
 151   abfd->tdata.plugin_data = plugin_data;
 152   return LDPS_OK;
 153 }
 154
 155 static const char *plugin_program_name;
 156
 157 void
 158 bfd_plugin_set_program_name (const char *program_name)
 159 {
 160   plugin_program_name = program_name;
 161 }
 162
 163 int
 164 bfd_plugin_open_input (bfd *ibfd, struct ld_plugin_input_file *file)
 165 {
 166   bfd *iobfd;
 167
 168   iobfd = ibfd;
 169   while (iobfd->my_archive
 170          && !bfd_is_thin_archive (iobfd->my_archive))
 171     iobfd = iobfd->my_archive;
 172   file->name = iobfd->filename;
 173
 174   if (!iobfd->iostream && !bfd_open_file (iobfd))
 175     return 0;
 176
 177   /* The plugin API expects that the file descriptor won't be closed
 178      and reused as done by the bfd file cache.  So open it again.
 179      dup isn't good enough.  plugin IO uses lseek/read while BFD uses
 180      fseek/fread.  It isn't wise to mix the unistd and stdio calls on
 181      the same underlying file descriptor.  */
 182   file->fd = open (file->name, O_RDONLY | O_BINARY);
 183   if (file->fd < 0)
 184     return 0;
 185
 186   if (iobfd == ibfd)
 187     {
 188       struct stat stat_buf;
 189       if (fstat (file->fd, &stat_buf))
 190         return 0;
 191       file->offset = 0;
 192       file->filesize = stat_buf.st_size;
 193     }
 194   else
 195     {
 196       file->offset = ibfd->origin;
 197       file->filesize = arelt_size (ibfd);
 198     }
 199   return 1;
 200 }
 201
 202 static int
 203 try_claim (bfd *abfd)
 204 {
 205   int claimed = 0;
 206   struct ld_plugin_input_file file;
 207
 208   file.handle = abfd;
 209   if (!bfd_plugin_open_input (abfd, &file))
 210     return 0;
 211   claim_file (&file, &claimed);
 212   if (!claimed)
 213     close (file.fd);
 214   return claimed;
 215 }
 216
 217 static int
 218 try_load_plugin (const char *pname, bfd *abfd, int *has_plugin_p)
 219 {
 220   void *plugin_handle;
 221   struct ld_plugin_tv tv[4];
 222   int i;
 223   ld_plugin_onload onload;
 224   enum ld_plugin_status status;
 225
 226   *has_plugin_p = 0;
 227
 228   plugin_handle = dlopen (pname, RTLD_NOW);
 229   if (!plugin_handle)
 230     {
 231       _bfd_error_handler ("%s\n", dlerror ());
 232       return 0;
 233     }
 234
 235   onload = dlsym (plugin_handle, "onload");
 236   if (!onload)
 237     goto err;
 238
 239   i = 0;
 240   tv[i].tv_tag = LDPT_MESSAGE;
 241   tv[i].tv_u.tv_message = message;
 242
 243   ++i;
 244   tv[i].tv_tag = LDPT_REGISTER_CLAIM_FILE_HOOK;
 245   tv[i].tv_u.tv_register_claim_file = register_claim_file;
 246
 247   ++i;
 248   tv[i].tv_tag = LDPT_ADD_SYMBOLS;
 249   tv[i].tv_u.tv_add_symbols = add_symbols;
 250
 251   ++i;
 252   tv[i].tv_tag = LDPT_NULL;
 253   tv[i].tv_u.tv_val = 0;
 254
 255   status = (*onload)(tv);
 256
 257   if (status != LDPS_OK)
 258     goto err;
 259
 260   *has_plugin_p = 1;
 261
 262   abfd->plugin_format = bfd_plugin_no;
 263
 264   if (!claim_file)
 265     goto err;
 266
 267   if (!try_claim (abfd))
 268     goto err;
 269
 270   abfd->plugin_format = bfd_plugin_yes;
 271
 272   return 1;
 273
 274  err:
 275   return 0;
 276 }
 277
 278 /* There may be plugin libraries in lib/bfd-plugins.  */
 279
 280 static int has_plugin = -1;
 281
 282 static const bfd_target *(*ld_plugin_object_p) (bfd *);
 283
 284 static const char *plugin_name;
 285
 286 void
 287 bfd_plugin_set_plugin (const char *p)
 288 {
 289   plugin_name = p;
 290   has_plugin = p != NULL;
 291 }
 292
 293 /* Return TRUE if a plugin library is used.  */
 294
 295 bfd_boolean
 296 bfd_plugin_specified_p (void)
 297 {
 298   return has_plugin > 0;
 299 }
 300
 301 /* Return TRUE if ABFD can be claimed by linker LTO plugin.  */
 302
 303 bfd_boolean
 304 bfd_link_plugin_object_p (bfd *abfd)
 305 {
 306   if (ld_plugin_object_p)
 307     return ld_plugin_object_p (abfd) != NULL;
 308   return FALSE;
 309 }
 310
 311 extern const bfd_target plugin_vec;
 312
 313 /* Return TRUE if TARGET is a pointer to plugin_vec.  */
 314
 315 bfd_boolean
 316 bfd_plugin_target_p (const bfd_target *target)
 317 {
 318   return target == &plugin_vec;
 319 }
 320
 321 /* Register OBJECT_P to be used by bfd_plugin_object_p.  */
 322
 323 void
 324 register_ld_plugin_object_p (const bfd_target *(*object_p) (bfd *))
 325 {
 326   ld_plugin_object_p = object_p;
 327 }
 328
 329 static int
 330 load_plugin (bfd *abfd)
 331 {
 332   char *plugin_dir;
 333   char *p;
 334   DIR *d;
 335   struct dirent *ent;
 336   int found = 0;
 337
 338   if (!has_plugin)
 339     return found;
 340
 341   if (plugin_name)
 342     return try_load_plugin (plugin_name, abfd, &has_plugin);
 343
 344   if (plugin_program_name == NULL)
 345     return found;
 346
 347   plugin_dir = concat (BINDIR, "/../lib/bfd-plugins", NULL);
 348   p = make_relative_prefix (plugin_program_name,
 349                             BINDIR,
 350                             plugin_dir);
 351   free (plugin_dir);
 352   plugin_dir = NULL;
 353
 354   d = opendir (p);
 355   if (!d)
 356     goto out;
 357
 358   while ((ent = readdir (d)))
 359     {
 360       char *full_name;
 361       struct stat s;
 362       int valid_plugin;
 363
 364       full_name = concat (p, "/", ent->d_name, NULL);
 365       if (stat(full_name, &s) == 0 && S_ISREG (s.st_mode))
 366         found = try_load_plugin (full_name, abfd, &valid_plugin);
 367       if (has_plugin <= 0)
 368         has_plugin = valid_plugin;
 369       free (full_name);
 370       if (found)
 371         break;
 372     }
 373
 374  out:
 375   free (p);
 376   if (d)
 377     closedir (d);
 378
 379   return found;
 380 }
 381
 382
 383 static const bfd_target *
 384 bfd_plugin_object_p (bfd *abfd)
 385 {
 386   if (ld_plugin_object_p)
 387     return ld_plugin_object_p (abfd);
 388
 389   if (abfd->plugin_format == bfd_plugin_unknown && !load_plugin (abfd))
 390     return NULL;
 391
 392   return abfd->plugin_format == bfd_plugin_yes ? abfd->xvec : NULL;
 393 }
 394
 395 /* Copy any private info we understand from the input bfd
 396    to the output bfd.  */
 397
 398 static bfd_boolean
 399 bfd_plugin_bfd_copy_private_bfd_data (bfd *ibfd ATTRIBUTE_UNUSED,
 400                                       bfd *obfd ATTRIBUTE_UNUSED)
 401 {
 402   BFD_ASSERT (0);
 403   return TRUE;
 404 }
 405
 406 /* Copy any private info we understand from the input section
 407    to the output section.  */
 408
 409 static bfd_boolean
 410 bfd_plugin_bfd_copy_private_section_data (bfd *ibfd ATTRIBUTE_UNUSED,
 411                                           asection *isection ATTRIBUTE_UNUSED,
 412                                           bfd *obfd ATTRIBUTE_UNUSED,
 413                                           asection *osection ATTRIBUTE_UNUSED)
 414 {
 415   BFD_ASSERT (0);
 416   return TRUE;
 417 }
 418
 419 /* Copy any private info we understand from the input symbol
 420    to the output symbol.  */
 421
 422 static bfd_boolean
 423 bfd_plugin_bfd_copy_private_symbol_data (bfd *ibfd ATTRIBUTE_UNUSED,
 424                                          asymbol *isymbol ATTRIBUTE_UNUSED,
 425                                          bfd *obfd ATTRIBUTE_UNUSED,
 426                                          asymbol *osymbol ATTRIBUTE_UNUSED)
 427 {
 428   BFD_ASSERT (0);
 429   return TRUE;
 430 }
 431
 432 static bfd_boolean
 433 bfd_plugin_bfd_print_private_bfd_data (bfd *abfd ATTRIBUTE_UNUSED, PTR ptr ATTRIBUTE_UNUSED)
 434 {
 435   BFD_ASSERT (0);
 436   return TRUE;
 437 }
 438
 439 static char *
 440 bfd_plugin_core_file_failing_command (bfd *abfd ATTRIBUTE_UNUSED)
 441 {
 442   BFD_ASSERT (0);
 443   return NULL;
 444 }
 445
 446 static int
 447 bfd_plugin_core_file_failing_signal (bfd *abfd ATTRIBUTE_UNUSED)
 448 {
 449   BFD_ASSERT (0);
 450   return 0;
 451 }
 452
 453 static int
 454 bfd_plugin_core_file_pid (bfd *abfd ATTRIBUTE_UNUSED)
 455 {
 456   BFD_ASSERT (0);
 457   return 0;
 458 }
 459
 460 static long
 461 bfd_plugin_get_symtab_upper_bound (bfd *abfd)
 462 {
 463   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
 464   long nsyms = plugin_data->nsyms;
 465
 466   BFD_ASSERT (nsyms >= 0);
 467
 468   return ((nsyms + 1) * sizeof (asymbol *));
 469 }
 470
 471 static flagword
 472 convert_flags (const struct ld_plugin_symbol *sym)
 473 {
 474  switch (sym->def)
 475    {
 476    case LDPK_DEF:
 477    case LDPK_COMMON:
 478    case LDPK_UNDEF:
 479      return BSF_GLOBAL;
 480
 481    case LDPK_WEAKUNDEF:
 482    case LDPK_WEAKDEF:
 483      return BSF_GLOBAL | BSF_WEAK;
 484
 485    default:
 486      BFD_ASSERT (0);
 487      return 0;
 488    }
 489 }
 490
 491 static long
 492 bfd_plugin_canonicalize_symtab (bfd *abfd,
 493                                 asymbol **alocation)
 494 {
 495   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
 496   long nsyms = plugin_data->nsyms;
 497   const struct ld_plugin_symbol *syms = plugin_data->syms;
 498   static asection fake_section;
 499   static asection fake_common_section;
 500   int i;
 501
 502   fake_section.name = ".text";
 503   fake_common_section.flags = SEC_IS_COMMON;
 504
 505   for (i = 0; i < nsyms; i++)
 506     {
 507       asymbol *s = bfd_alloc (abfd, sizeof (asymbol));
 508
 509       BFD_ASSERT (s);
 510       alocation[i] = s;
 511
 512       s->the_bfd = abfd;
 513       s->name = syms[i].name;
 514       s->value = 0;
 515       s->flags = convert_flags (&syms[i]);
 516       switch (syms[i].def)
 517         {
 518         case LDPK_COMMON:
 519           s->section = &fake_common_section;
 520           break;
 521         case LDPK_UNDEF:
 522         case LDPK_WEAKUNDEF:
 523           s->section = bfd_und_section_ptr;
 524           break;
 525         case LDPK_DEF:
 526         case LDPK_WEAKDEF:
 527           s->section = &fake_section;
 528           break;
 529         default:
 530           BFD_ASSERT (0);
 531         }
 532
 533       s->udata.p = (void *) &syms[i];
 534     }
 535
 536   return nsyms;
 537 }
 538
 539 static void
 540 bfd_plugin_print_symbol (bfd *abfd ATTRIBUTE_UNUSED,
 541                          PTR afile ATTRIBUTE_UNUSED,
 542                          asymbol *symbol ATTRIBUTE_UNUSED,
 543                          bfd_print_symbol_type how ATTRIBUTE_UNUSED)
 544 {
 545   BFD_ASSERT (0);
 546 }
 547
 548 static void
 549 bfd_plugin_get_symbol_info (bfd *abfd ATTRIBUTE_UNUSED,
 550                             asymbol *symbol,
 551                             symbol_info *ret)
 552 {
 553   bfd_symbol_info (symbol, ret);
 554 }
 555
 556 /* Make an empty symbol. */
 557
 558 static asymbol *
 559 bfd_plugin_make_empty_symbol (bfd *abfd)
 560 {
 561   asymbol *new_symbol = bfd_zalloc (abfd, sizeof (asymbol));
 562   if (new_symbol == NULL)
 563     return new_symbol;
 564   new_symbol->the_bfd = abfd;
 565   return new_symbol;
 566 }
 567
 568 static int
 569 bfd_plugin_sizeof_headers (bfd *a ATTRIBUTE_UNUSED,
 570                            struct bfd_link_info *info ATTRIBUTE_UNUSED)
 571 {
 572   BFD_ASSERT (0);
 573   return 0;
 574 }
 575
 576 const bfd_target plugin_vec =
 577 {
 578   "plugin",                     /* Name.  */
 579   bfd_target_unknown_flavour,
 580   BFD_ENDIAN_LITTLE,            /* Target byte order.  */
 581   BFD_ENDIAN_LITTLE,            /* Target headers byte order.  */
 582   (HAS_RELOC | EXEC_P |         /* Object flags.  */
 583    HAS_LINENO | HAS_DEBUG |
 584    HAS_SYMS | HAS_LOCALS | DYNAMIC | WP_TEXT | D_PAGED),
 585   (SEC_CODE | SEC_DATA | SEC_ROM | SEC_HAS_CONTENTS
 586    | SEC_ALLOC | SEC_LOAD | SEC_RELOC), /* Section flags.  */
 587   0,                            /* symbol_leading_char.  */
 588   '/',                          /* ar_pad_char.  */
 589   15,                           /* ar_max_namelen.  */
 590   255,                          /* match priority.  */
 591
 592   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 593   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 594   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* data */
 595   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 596   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 597   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* hdrs */
 598
 599   {                             /* bfd_check_format.  */
 600     _bfd_dummy_target,
 601     bfd_plugin_object_p,
 602     bfd_generic_archive_p,
 603     _bfd_dummy_target
 604   },
 605   {                             /* bfd_set_format.  */
 606     _bfd_bool_bfd_false_error,
 607     _bfd_bool_bfd_false_error,
 608     _bfd_generic_mkarchive,
 609     _bfd_bool_bfd_false_error,
 610   },
 611   {                             /* bfd_write_contents.  */
 612     _bfd_bool_bfd_false_error,
 613     _bfd_bool_bfd_false_error,
 614     _bfd_write_archive_contents,
 615     _bfd_bool_bfd_false_error,
 616   },
 617
 618   BFD_JUMP_TABLE_GENERIC (bfd_plugin),
 619   BFD_JUMP_TABLE_COPY (bfd_plugin),
 620   BFD_JUMP_TABLE_CORE (bfd_plugin),
 621 #ifdef USE_64_BIT_ARCHIVE
 622   BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_64_bit),
 623 #else
 624   BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
 625 #endif
 626   BFD_JUMP_TABLE_SYMBOLS (bfd_plugin),
 627   BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
 628   BFD_JUMP_TABLE_WRITE (bfd_plugin),
 629   BFD_JUMP_TABLE_LINK (bfd_plugin),
 630   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 631
 632   NULL,
 633
 634   NULL                          /* backend_data.  */
 635 };
 636 #endif /* BFD_SUPPORTS_PLUGIN */