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