bfd/plugin.c

   1 /* Plugin support for BFD.
   2    Copyright (C) 2009-2015 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
 110 static enum ld_plugin_status
 111 message (int level ATTRIBUTE_UNUSED,
 112          const char * format, ...)
 113 {
 114   va_list args;
 115   va_start (args, format);
 116   printf ("bfd plugin: ");
 117   vprintf (format, args);
 118   putchar ('\n');
 119   va_end (args);
 120   return LDPS_OK;
 121 }
 122
 123 /* Register a claim-file handler. */
 124 static ld_plugin_claim_file_handler claim_file;
 125
 126 static enum ld_plugin_status
 127 register_claim_file (ld_plugin_claim_file_handler handler)
 128 {
 129   claim_file = handler;
 130   return LDPS_OK;
 131 }
 132
 133 static enum ld_plugin_status
 134 add_symbols (void * handle,
 135              int nsyms,
 136              const struct ld_plugin_symbol * syms)
 137 {
 138   bfd *abfd = handle;
 139   struct plugin_data_struct *plugin_data =
 140     bfd_alloc (abfd, sizeof (plugin_data_struct));
 141
 142   plugin_data->nsyms = nsyms;
 143   plugin_data->syms = syms;
 144
 145   if (nsyms != 0)
 146     abfd->flags |= HAS_SYMS;
 147
 148   abfd->tdata.plugin_data = plugin_data;
 149   return LDPS_OK;
 150 }
 151
 152 static const char *plugin_program_name;
 153
 154 void
 155 bfd_plugin_set_program_name (const char *program_name)
 156 {
 157   plugin_program_name = program_name;
 158 }
 159
 160 static int
 161 try_claim (bfd *abfd)
 162 {
 163   int claimed = 0;
 164   struct ld_plugin_input_file file;
 165   bfd *iobfd;
 166
 167   file.name = abfd->filename;
 168
 169   if (abfd->my_archive)
 170     {
 171       iobfd = abfd->my_archive;
 172       file.offset = abfd->origin;
 173       file.filesize = arelt_size (abfd);
 174     }
 175   else
 176     {
 177       iobfd = abfd;
 178       file.offset = 0;
 179       file.filesize = 0;
 180     }
 181
 182   if (!iobfd->iostream && !bfd_open_file (iobfd))
 183     return 0;
 184
 185   file.fd = fileno ((FILE *) iobfd->iostream);
 186
 187   if (!abfd->my_archive)
 188     {
 189       struct stat stat_buf;
 190       if (fstat (file.fd, &stat_buf))
 191         return 0;
 192       file.filesize = stat_buf.st_size;
 193     }
 194
 195   file.handle = abfd;
 196   off_t cur_offset = lseek(file.fd, 0, SEEK_CUR);
 197   claim_file (&file, &claimed);
 198   lseek(file.fd, cur_offset, SEEK_SET);
 199   if (!claimed)
 200     return 0;
 201
 202   return 1;
 203 }
 204
 205 static int
 206 try_load_plugin (const char *pname, bfd *abfd, int *has_plugin_p)
 207 {
 208   void *plugin_handle;
 209   int tv_size = 4;
 210   struct ld_plugin_tv tv[tv_size];
 211   int i;
 212   ld_plugin_onload onload;
 213   enum ld_plugin_status status;
 214
 215   *has_plugin_p = 0;
 216
 217   plugin_handle = dlopen (pname, RTLD_NOW);
 218   if (!plugin_handle)
 219     {
 220       (*_bfd_error_handler)("%s\n", dlerror ());
 221       return 0;
 222     }
 223
 224   onload = dlsym (plugin_handle, "onload");
 225   if (!onload)
 226     goto err;
 227
 228   i = 0;
 229   tv[i].tv_tag = LDPT_MESSAGE;
 230   tv[i].tv_u.tv_message = message;
 231
 232   ++i;
 233   tv[i].tv_tag = LDPT_REGISTER_CLAIM_FILE_HOOK;
 234   tv[i].tv_u.tv_register_claim_file = register_claim_file;
 235
 236   ++i;
 237   tv[i].tv_tag = LDPT_ADD_SYMBOLS;
 238   tv[i].tv_u.tv_add_symbols = add_symbols;
 239
 240   ++i;
 241   tv[i].tv_tag = LDPT_NULL;
 242   tv[i].tv_u.tv_val = 0;
 243
 244   status = (*onload)(tv);
 245
 246   if (status != LDPS_OK)
 247     goto err;
 248
 249   *has_plugin_p = 1;
 250
 251   abfd->plugin_format = bfd_plugin_no;
 252
 253   if (!claim_file)
 254     goto err;
 255
 256   if (!try_claim (abfd))
 257     goto err;
 258
 259   abfd->plugin_format = bfd_plugin_yes;
 260
 261   return 1;
 262
 263  err:
 264   return 0;
 265 }
 266
 267 /* There may be plugin libraries in lib/bfd-plugins.  */
 268
 269 static int has_plugin = -1;
 270
 271 static const bfd_target *(*ld_plugin_object_p) (bfd *);
 272
 273 static const char *plugin_name;
 274
 275 void
 276 bfd_plugin_set_plugin (const char *p)
 277 {
 278   plugin_name = p;
 279   has_plugin = p != NULL;
 280 }
 281
 282 /* Return TRUE if a plugin library is used.  */
 283
 284 bfd_boolean
 285 bfd_plugin_specified_p (void)
 286 {
 287   return has_plugin > 0;
 288 }
 289
 290 extern const bfd_target plugin_vec;
 291
 292 /* Return TRUE if TARGET is a pointer to plugin_vec.  */
 293
 294 bfd_boolean
 295 bfd_plugin_target_p (const bfd_target *target)
 296 {
 297   return target == &plugin_vec;
 298 }
 299
 300 /* Register OBJECT_P to be used by bfd_plugin_object_p.  */
 301
 302 void
 303 register_ld_plugin_object_p (const bfd_target *(*object_p) (bfd *))
 304 {
 305   ld_plugin_object_p = object_p;
 306 }
 307
 308 static int
 309 load_plugin (bfd *abfd)
 310 {
 311   char *plugin_dir;
 312   char *p;
 313   DIR *d;
 314   struct dirent *ent;
 315   int found = 0;
 316
 317   if (!has_plugin)
 318     return found;
 319
 320   if (plugin_name)
 321     return try_load_plugin (plugin_name, abfd, &has_plugin);
 322
 323   if (plugin_program_name == NULL)
 324     return found;
 325
 326   plugin_dir = concat (BINDIR, "/../lib/bfd-plugins", NULL);
 327   p = make_relative_prefix (plugin_program_name,
 328                             BINDIR,
 329                             plugin_dir);
 330   free (plugin_dir);
 331   plugin_dir = NULL;
 332
 333   d = opendir (p);
 334   if (!d)
 335     goto out;
 336
 337   while ((ent = readdir (d)))
 338     {
 339       char *full_name;
 340       struct stat s;
 341       int valid_plugin;
 342
 343       full_name = concat (p, "/", ent->d_name, NULL);
 344       if (stat(full_name, &s) == 0 && S_ISREG (s.st_mode))
 345         found = try_load_plugin (full_name, abfd, &valid_plugin);
 346       if (has_plugin <= 0)
 347         has_plugin = valid_plugin;
 348       free (full_name);
 349       if (found)
 350         break;
 351     }
 352
 353  out:
 354   free (p);
 355   if (d)
 356     closedir (d);
 357
 358   return found;
 359 }
 360
 361
 362 static const bfd_target *
 363 bfd_plugin_object_p (bfd *abfd)
 364 {
 365   if (ld_plugin_object_p)
 366     return ld_plugin_object_p (abfd);
 367
 368   if (abfd->plugin_format == bfd_plugin_uknown && !load_plugin (abfd))
 369     return NULL;
 370
 371   return abfd->plugin_format == bfd_plugin_yes ? abfd->xvec : NULL;
 372 }
 373
 374 /* Copy any private info we understand from the input bfd
 375    to the output bfd.  */
 376
 377 static bfd_boolean
 378 bfd_plugin_bfd_copy_private_bfd_data (bfd *ibfd ATTRIBUTE_UNUSED,
 379                                       bfd *obfd ATTRIBUTE_UNUSED)
 380 {
 381   BFD_ASSERT (0);
 382   return TRUE;
 383 }
 384
 385 /* Copy any private info we understand from the input section
 386    to the output section.  */
 387
 388 static bfd_boolean
 389 bfd_plugin_bfd_copy_private_section_data (bfd *ibfd ATTRIBUTE_UNUSED,
 390                                           asection *isection ATTRIBUTE_UNUSED,
 391                                           bfd *obfd ATTRIBUTE_UNUSED,
 392                                           asection *osection ATTRIBUTE_UNUSED)
 393 {
 394   BFD_ASSERT (0);
 395   return TRUE;
 396 }
 397
 398 /* Copy any private info we understand from the input symbol
 399    to the output symbol.  */
 400
 401 static bfd_boolean
 402 bfd_plugin_bfd_copy_private_symbol_data (bfd *ibfd ATTRIBUTE_UNUSED,
 403                                          asymbol *isymbol ATTRIBUTE_UNUSED,
 404                                          bfd *obfd ATTRIBUTE_UNUSED,
 405                                          asymbol *osymbol ATTRIBUTE_UNUSED)
 406 {
 407   BFD_ASSERT (0);
 408   return TRUE;
 409 }
 410
 411 static bfd_boolean
 412 bfd_plugin_bfd_print_private_bfd_data (bfd *abfd ATTRIBUTE_UNUSED, PTR ptr ATTRIBUTE_UNUSED)
 413 {
 414   BFD_ASSERT (0);
 415   return TRUE;
 416 }
 417
 418 static char *
 419 bfd_plugin_core_file_failing_command (bfd *abfd ATTRIBUTE_UNUSED)
 420 {
 421   BFD_ASSERT (0);
 422   return NULL;
 423 }
 424
 425 static int
 426 bfd_plugin_core_file_failing_signal (bfd *abfd ATTRIBUTE_UNUSED)
 427 {
 428   BFD_ASSERT (0);
 429   return 0;
 430 }
 431
 432 static int
 433 bfd_plugin_core_file_pid (bfd *abfd ATTRIBUTE_UNUSED)
 434 {
 435   BFD_ASSERT (0);
 436   return 0;
 437 }
 438
 439 static long
 440 bfd_plugin_get_symtab_upper_bound (bfd *abfd)
 441 {
 442   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
 443   long nsyms = plugin_data->nsyms;
 444
 445   BFD_ASSERT (nsyms >= 0);
 446
 447   return ((nsyms + 1) * sizeof (asymbol *));
 448 }
 449
 450 static flagword
 451 convert_flags (const struct ld_plugin_symbol *sym)
 452 {
 453  switch (sym->def)
 454    {
 455    case LDPK_DEF:
 456    case LDPK_COMMON:
 457    case LDPK_UNDEF:
 458      return BSF_GLOBAL;
 459
 460    case LDPK_WEAKUNDEF:
 461    case LDPK_WEAKDEF:
 462      return BSF_GLOBAL | BSF_WEAK;
 463
 464    default:
 465      BFD_ASSERT (0);
 466      return 0;
 467    }
 468 }
 469
 470 static long
 471 bfd_plugin_canonicalize_symtab (bfd *abfd,
 472                                 asymbol **alocation)
 473 {
 474   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
 475   long nsyms = plugin_data->nsyms;
 476   const struct ld_plugin_symbol *syms = plugin_data->syms;
 477   static asection fake_section;
 478   static asection fake_common_section;
 479   int i;
 480
 481   fake_section.name = ".text";
 482   fake_common_section.flags = SEC_IS_COMMON;
 483
 484   for (i = 0; i < nsyms; i++)
 485     {
 486       asymbol *s = bfd_alloc (abfd, sizeof (asymbol));
 487
 488       BFD_ASSERT (s);
 489       alocation[i] = s;
 490
 491       s->the_bfd = abfd;
 492       s->name = syms[i].name;
 493       s->value = 0;
 494       s->flags = convert_flags (&syms[i]);
 495       switch (syms[i].def)
 496         {
 497         case LDPK_COMMON:
 498           s->section = &fake_common_section;
 499           break;
 500         case LDPK_UNDEF:
 501         case LDPK_WEAKUNDEF:
 502           s->section = bfd_und_section_ptr;
 503           break;
 504         case LDPK_DEF:
 505         case LDPK_WEAKDEF:
 506           s->section = &fake_section;
 507           break;
 508         default:
 509           BFD_ASSERT (0);
 510         }
 511
 512       s->udata.p = (void *) &syms[i];
 513     }
 514
 515   return nsyms;
 516 }
 517
 518 static void
 519 bfd_plugin_print_symbol (bfd *abfd ATTRIBUTE_UNUSED,
 520                          PTR afile ATTRIBUTE_UNUSED,
 521                          asymbol *symbol ATTRIBUTE_UNUSED,
 522                          bfd_print_symbol_type how ATTRIBUTE_UNUSED)
 523 {
 524   BFD_ASSERT (0);
 525 }
 526
 527 static void
 528 bfd_plugin_get_symbol_info (bfd *abfd ATTRIBUTE_UNUSED,
 529                             asymbol *symbol,
 530                             symbol_info *ret)
 531 {
 532   bfd_symbol_info (symbol, ret);
 533 }
 534
 535 /* Make an empty symbol. */
 536
 537 static asymbol *
 538 bfd_plugin_make_empty_symbol (bfd *abfd)
 539 {
 540   asymbol *new_symbol = bfd_zalloc (abfd, sizeof (asymbol));
 541   if (new_symbol == NULL)
 542     return new_symbol;
 543   new_symbol->the_bfd = abfd;
 544   return new_symbol;
 545 }
 546
 547 static int
 548 bfd_plugin_sizeof_headers (bfd *a ATTRIBUTE_UNUSED,
 549                            struct bfd_link_info *info ATTRIBUTE_UNUSED)
 550 {
 551   BFD_ASSERT (0);
 552   return 0;
 553 }
 554
 555 const bfd_target plugin_vec =
 556 {
 557   "plugin",                     /* Name.  */
 558   bfd_target_unknown_flavour,
 559   BFD_ENDIAN_LITTLE,            /* Target byte order.  */
 560   BFD_ENDIAN_LITTLE,            /* Target headers byte order.  */
 561   (HAS_RELOC | EXEC_P |         /* Object flags.  */
 562    HAS_LINENO | HAS_DEBUG |
 563    HAS_SYMS | HAS_LOCALS | DYNAMIC | WP_TEXT | D_PAGED),
 564   (SEC_CODE | SEC_DATA | SEC_ROM | SEC_HAS_CONTENTS
 565    | SEC_ALLOC | SEC_LOAD | SEC_RELOC), /* Section flags.  */
 566   0,                            /* symbol_leading_char.  */
 567   '/',                          /* ar_pad_char.  */
 568   15,                           /* ar_max_namelen.  */
 569   0,                            /* match priority.  */
 570
 571   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 572   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 573   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* data */
 574   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 575   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 576   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* hdrs */
 577
 578   {                             /* bfd_check_format.  */
 579     _bfd_dummy_target,
 580     bfd_plugin_object_p,
 581     bfd_generic_archive_p,
 582     _bfd_dummy_target
 583   },
 584   {                             /* bfd_set_format.  */
 585     bfd_false,
 586     bfd_false,
 587     _bfd_generic_mkarchive,
 588     bfd_false,
 589   },
 590   {                             /* bfd_write_contents.  */
 591     bfd_false,
 592     bfd_false,
 593     _bfd_write_archive_contents,
 594     bfd_false,
 595   },
 596
 597   BFD_JUMP_TABLE_GENERIC (bfd_plugin),
 598   BFD_JUMP_TABLE_COPY (bfd_plugin),
 599   BFD_JUMP_TABLE_CORE (bfd_plugin),
 600   BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
 601   BFD_JUMP_TABLE_SYMBOLS (bfd_plugin),
 602   BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
 603   BFD_JUMP_TABLE_WRITE (bfd_plugin),
 604   BFD_JUMP_TABLE_LINK (bfd_plugin),
 605   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 606
 607   NULL,
 608
 609   NULL                          /* backend_data.  */
 610 };
 611 #endif /* BFD_SUPPORTS_PLUGIN */