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 = NULL;
 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
 190       if (fstat (file->fd, &stat_buf))
 191         {
 192           close(file->fd);
 193           return 0;
 194         }
 195
 196       file->offset = 0;
 197       file->filesize = stat_buf.st_size;
 198     }
 199   else
 200     {
 201       file->offset = ibfd->origin;
 202       file->filesize = arelt_size (ibfd);
 203     }
 204   return 1;
 205 }
 206
 207 static int
 208 try_claim (bfd *abfd)
 209 {
 210   int claimed = 0;
 211   struct ld_plugin_input_file file;
 212
 213   file.handle = abfd;
 214   if (!bfd_plugin_open_input (abfd, &file))
 215     return 0;
 216   if (claim_file)
 217     claim_file (&file, &claimed);
 218   close (file.fd);
 219   return claimed;
 220 }
 221
 222 static int
 223 try_load_plugin (const char *pname, bfd *abfd, int *has_plugin_p)
 224 {
 225   void *plugin_handle = NULL;
 226   struct ld_plugin_tv tv[4];
 227   int i;
 228   ld_plugin_onload onload;
 229   enum ld_plugin_status status;
 230
 231   if (claim_file)
 232     goto have_claim_file;
 233
 234   *has_plugin_p = 0;
 235
 236   plugin_handle = dlopen (pname, RTLD_NOW);
 237   if (!plugin_handle)
 238     {
 239       _bfd_error_handler ("%s\n", dlerror ());
 240       return 0;
 241     }
 242
 243   onload = dlsym (plugin_handle, "onload");
 244   if (!onload)
 245     goto err;
 246
 247   i = 0;
 248   tv[i].tv_tag = LDPT_MESSAGE;
 249   tv[i].tv_u.tv_message = message;
 250
 251   ++i;
 252   tv[i].tv_tag = LDPT_REGISTER_CLAIM_FILE_HOOK;
 253   tv[i].tv_u.tv_register_claim_file = register_claim_file;
 254
 255   ++i;
 256   tv[i].tv_tag = LDPT_ADD_SYMBOLS;
 257   tv[i].tv_u.tv_add_symbols = add_symbols;
 258
 259   ++i;
 260   tv[i].tv_tag = LDPT_NULL;
 261   tv[i].tv_u.tv_val = 0;
 262
 263   status = (*onload)(tv);
 264
 265   if (status != LDPS_OK)
 266     goto err;
 267
 268 have_claim_file:
 269   *has_plugin_p = 1;
 270
 271   abfd->plugin_format = bfd_plugin_no;
 272
 273   if (!claim_file)
 274     goto err;
 275
 276   if (!try_claim (abfd))
 277     goto err;
 278
 279   abfd->plugin_format = bfd_plugin_yes;
 280
 281   return 1;
 282
 283  err:
 284   if (plugin_handle)
 285     dlclose (plugin_handle);
 286   register_claim_file (NULL);
 287   return 0;
 288 }
 289
 290 /* There may be plugin libraries in lib/bfd-plugins.  */
 291
 292 static int has_plugin = -1;
 293
 294 static const bfd_target *(*ld_plugin_object_p) (bfd *);
 295
 296 static const char *plugin_name;
 297
 298 void
 299 bfd_plugin_set_plugin (const char *p)
 300 {
 301   plugin_name = p;
 302   has_plugin = p != NULL;
 303 }
 304
 305 /* Return TRUE if a plugin library is used.  */
 306
 307 bfd_boolean
 308 bfd_plugin_specified_p (void)
 309 {
 310   return has_plugin > 0;
 311 }
 312
 313 /* Return TRUE if ABFD can be claimed by linker LTO plugin.  */
 314
 315 bfd_boolean
 316 bfd_link_plugin_object_p (bfd *abfd)
 317 {
 318   if (ld_plugin_object_p)
 319     return ld_plugin_object_p (abfd) != NULL;
 320   return FALSE;
 321 }
 322
 323 extern const bfd_target plugin_vec;
 324
 325 /* Return TRUE if TARGET is a pointer to plugin_vec.  */
 326
 327 bfd_boolean
 328 bfd_plugin_target_p (const bfd_target *target)
 329 {
 330   return target == &plugin_vec;
 331 }
 332
 333 /* Register OBJECT_P to be used by bfd_plugin_object_p.  */
 334
 335 void
 336 register_ld_plugin_object_p (const bfd_target *(*object_p) (bfd *))
 337 {
 338   ld_plugin_object_p = object_p;
 339 }
 340
 341 static int
 342 load_plugin (bfd *abfd)
 343 {
 344   char *plugin_dir;
 345   char *p;
 346   DIR *d;
 347   struct dirent *ent;
 348   int found = 0;
 349
 350   if (!has_plugin)
 351     return found;
 352
 353   if (plugin_name)
 354     return try_load_plugin (plugin_name, abfd, &has_plugin);
 355
 356   if (plugin_program_name == NULL)
 357     return found;
 358
 359   plugin_dir = concat (BINDIR, "/../lib/bfd-plugins", NULL);
 360   p = make_relative_prefix (plugin_program_name,
 361                             BINDIR,
 362                             plugin_dir);
 363   free (plugin_dir);
 364   plugin_dir = NULL;
 365
 366   d = opendir (p);
 367   if (!d)
 368     goto out;
 369
 370   while ((ent = readdir (d)))
 371     {
 372       char *full_name;
 373       struct stat s;
 374       int valid_plugin;
 375
 376       full_name = concat (p, "/", ent->d_name, NULL);
 377       if (stat (full_name, &s) == 0 && S_ISREG (s.st_mode))
 378         found = try_load_plugin (full_name, abfd, &valid_plugin);
 379       if (has_plugin <= 0)
 380         has_plugin = valid_plugin;
 381       free (full_name);
 382       if (found)
 383         break;
 384     }
 385
 386  out:
 387   free (p);
 388   if (d)
 389     closedir (d);
 390
 391   return found;
 392 }
 393
 394
 395 static const bfd_target *
 396 bfd_plugin_object_p (bfd *abfd)
 397 {
 398   if (ld_plugin_object_p)
 399     return ld_plugin_object_p (abfd);
 400
 401   if (abfd->plugin_format == bfd_plugin_unknown && !load_plugin (abfd))
 402     return NULL;
 403
 404   return abfd->plugin_format == bfd_plugin_yes ? abfd->xvec : NULL;
 405 }
 406
 407 /* Copy any private info we understand from the input bfd
 408    to the output bfd.  */
 409
 410 static bfd_boolean
 411 bfd_plugin_bfd_copy_private_bfd_data (bfd *ibfd ATTRIBUTE_UNUSED,
 412                                       bfd *obfd ATTRIBUTE_UNUSED)
 413 {
 414   BFD_ASSERT (0);
 415   return TRUE;
 416 }
 417
 418 /* Copy any private info we understand from the input section
 419    to the output section.  */
 420
 421 static bfd_boolean
 422 bfd_plugin_bfd_copy_private_section_data (bfd *ibfd ATTRIBUTE_UNUSED,
 423                                           asection *isection ATTRIBUTE_UNUSED,
 424                                           bfd *obfd ATTRIBUTE_UNUSED,
 425                                           asection *osection ATTRIBUTE_UNUSED)
 426 {
 427   BFD_ASSERT (0);
 428   return TRUE;
 429 }
 430
 431 /* Copy any private info we understand from the input symbol
 432    to the output symbol.  */
 433
 434 static bfd_boolean
 435 bfd_plugin_bfd_copy_private_symbol_data (bfd *ibfd ATTRIBUTE_UNUSED,
 436                                          asymbol *isymbol ATTRIBUTE_UNUSED,
 437                                          bfd *obfd ATTRIBUTE_UNUSED,
 438                                          asymbol *osymbol ATTRIBUTE_UNUSED)
 439 {
 440   BFD_ASSERT (0);
 441   return TRUE;
 442 }
 443
 444 static bfd_boolean
 445 bfd_plugin_bfd_print_private_bfd_data (bfd *abfd ATTRIBUTE_UNUSED, PTR ptr ATTRIBUTE_UNUSED)
 446 {
 447   BFD_ASSERT (0);
 448   return TRUE;
 449 }
 450
 451 static char *
 452 bfd_plugin_core_file_failing_command (bfd *abfd ATTRIBUTE_UNUSED)
 453 {
 454   BFD_ASSERT (0);
 455   return NULL;
 456 }
 457
 458 static int
 459 bfd_plugin_core_file_failing_signal (bfd *abfd ATTRIBUTE_UNUSED)
 460 {
 461   BFD_ASSERT (0);
 462   return 0;
 463 }
 464
 465 static int
 466 bfd_plugin_core_file_pid (bfd *abfd ATTRIBUTE_UNUSED)
 467 {
 468   BFD_ASSERT (0);
 469   return 0;
 470 }
 471
 472 static long
 473 bfd_plugin_get_symtab_upper_bound (bfd *abfd)
 474 {
 475   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
 476   long nsyms = plugin_data->nsyms;
 477
 478   BFD_ASSERT (nsyms >= 0);
 479
 480   return ((nsyms + 1) * sizeof (asymbol *));
 481 }
 482
 483 static flagword
 484 convert_flags (const struct ld_plugin_symbol *sym)
 485 {
 486  switch (sym->def)
 487    {
 488    case LDPK_DEF:
 489    case LDPK_COMMON:
 490    case LDPK_UNDEF:
 491      return BSF_GLOBAL;
 492
 493    case LDPK_WEAKUNDEF:
 494    case LDPK_WEAKDEF:
 495      return BSF_GLOBAL | BSF_WEAK;
 496
 497    default:
 498      BFD_ASSERT (0);
 499      return 0;
 500    }
 501 }
 502
 503 static long
 504 bfd_plugin_canonicalize_symtab (bfd *abfd,
 505                                 asymbol **alocation)
 506 {
 507   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
 508   long nsyms = plugin_data->nsyms;
 509   const struct ld_plugin_symbol *syms = plugin_data->syms;
 510   static asection fake_section;
 511   static asection fake_common_section;
 512   int i;
 513
 514   fake_section.name = ".text";
 515   fake_common_section.flags = SEC_IS_COMMON;
 516
 517   for (i = 0; i < nsyms; i++)
 518     {
 519       asymbol *s = bfd_alloc (abfd, sizeof (asymbol));
 520
 521       BFD_ASSERT (s);
 522       alocation[i] = s;
 523
 524       s->the_bfd = abfd;
 525       s->name = syms[i].name;
 526       s->value = 0;
 527       s->flags = convert_flags (&syms[i]);
 528       switch (syms[i].def)
 529         {
 530         case LDPK_COMMON:
 531           s->section = &fake_common_section;
 532           break;
 533         case LDPK_UNDEF:
 534         case LDPK_WEAKUNDEF:
 535           s->section = bfd_und_section_ptr;
 536           break;
 537         case LDPK_DEF:
 538         case LDPK_WEAKDEF:
 539           s->section = &fake_section;
 540           break;
 541         default:
 542           BFD_ASSERT (0);
 543         }
 544
 545       s->udata.p = (void *) &syms[i];
 546     }
 547
 548   return nsyms;
 549 }
 550
 551 static void
 552 bfd_plugin_print_symbol (bfd *abfd ATTRIBUTE_UNUSED,
 553                          PTR afile ATTRIBUTE_UNUSED,
 554                          asymbol *symbol ATTRIBUTE_UNUSED,
 555                          bfd_print_symbol_type how ATTRIBUTE_UNUSED)
 556 {
 557   BFD_ASSERT (0);
 558 }
 559
 560 static void
 561 bfd_plugin_get_symbol_info (bfd *abfd ATTRIBUTE_UNUSED,
 562                             asymbol *symbol,
 563                             symbol_info *ret)
 564 {
 565   bfd_symbol_info (symbol, ret);
 566 }
 567
 568 /* Make an empty symbol. */
 569
 570 static asymbol *
 571 bfd_plugin_make_empty_symbol (bfd *abfd)
 572 {
 573   asymbol *new_symbol = bfd_zalloc (abfd, sizeof (asymbol));
 574   if (new_symbol == NULL)
 575     return new_symbol;
 576   new_symbol->the_bfd = abfd;
 577   return new_symbol;
 578 }
 579
 580 static int
 581 bfd_plugin_sizeof_headers (bfd *a ATTRIBUTE_UNUSED,
 582                            struct bfd_link_info *info ATTRIBUTE_UNUSED)
 583 {
 584   BFD_ASSERT (0);
 585   return 0;
 586 }
 587
 588 const bfd_target plugin_vec =
 589 {
 590   "plugin",                     /* Name.  */
 591   bfd_target_unknown_flavour,
 592   BFD_ENDIAN_LITTLE,            /* Target byte order.  */
 593   BFD_ENDIAN_LITTLE,            /* Target headers byte order.  */
 594   (HAS_RELOC | EXEC_P |         /* Object flags.  */
 595    HAS_LINENO | HAS_DEBUG |
 596    HAS_SYMS | HAS_LOCALS | DYNAMIC | WP_TEXT | D_PAGED),
 597   (SEC_CODE | SEC_DATA | SEC_ROM | SEC_HAS_CONTENTS
 598    | SEC_ALLOC | SEC_LOAD | SEC_RELOC), /* Section flags.  */
 599   0,                            /* symbol_leading_char.  */
 600   '/',                          /* ar_pad_char.  */
 601   15,                           /* ar_max_namelen.  */
 602   255,                          /* match priority.  */
 603
 604   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 605   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 606   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* data */
 607   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 608   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 609   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* hdrs */
 610
 611   {                             /* bfd_check_format.  */
 612     _bfd_dummy_target,
 613     bfd_plugin_object_p,
 614     bfd_generic_archive_p,
 615     _bfd_dummy_target
 616   },
 617   {                             /* bfd_set_format.  */
 618     _bfd_bool_bfd_false_error,
 619     _bfd_bool_bfd_false_error,
 620     _bfd_generic_mkarchive,
 621     _bfd_bool_bfd_false_error,
 622   },
 623   {                             /* bfd_write_contents.  */
 624     _bfd_bool_bfd_false_error,
 625     _bfd_bool_bfd_false_error,
 626     _bfd_write_archive_contents,
 627     _bfd_bool_bfd_false_error,
 628   },
 629
 630   BFD_JUMP_TABLE_GENERIC (bfd_plugin),
 631   BFD_JUMP_TABLE_COPY (bfd_plugin),
 632   BFD_JUMP_TABLE_CORE (bfd_plugin),
 633 #ifdef USE_64_BIT_ARCHIVE
 634   BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_64_bit),
 635 #else
 636   BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
 637 #endif
 638   BFD_JUMP_TABLE_SYMBOLS (bfd_plugin),
 639   BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
 640   BFD_JUMP_TABLE_WRITE (bfd_plugin),
 641   BFD_JUMP_TABLE_LINK (bfd_plugin),
 642   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 643
 644   NULL,
 645
 646   NULL                          /* backend_data.  */
 647 };
 648 #endif /* BFD_SUPPORTS_PLUGIN */