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