bfd/plugin.c

   1 /* Plugin support for BFD.
   2    Copyright (C) 2009-2016 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   struct ld_plugin_tv tv[4];
 210   int i;
 211   ld_plugin_onload onload;
 212   enum ld_plugin_status status;
 213
 214   *has_plugin_p = 0;
 215
 216   plugin_handle = dlopen (pname, RTLD_NOW);
 217   if (!plugin_handle)
 218     {
 219       (*_bfd_error_handler)("%s\n", dlerror ());
 220       return 0;
 221     }
 222
 223   onload = dlsym (plugin_handle, "onload");
 224   if (!onload)
 225     goto err;
 226
 227   i = 0;
 228   tv[i].tv_tag = LDPT_MESSAGE;
 229   tv[i].tv_u.tv_message = message;
 230
 231   ++i;
 232   tv[i].tv_tag = LDPT_REGISTER_CLAIM_FILE_HOOK;
 233   tv[i].tv_u.tv_register_claim_file = register_claim_file;
 234
 235   ++i;
 236   tv[i].tv_tag = LDPT_ADD_SYMBOLS;
 237   tv[i].tv_u.tv_add_symbols = add_symbols;
 238
 239   ++i;
 240   tv[i].tv_tag = LDPT_NULL;
 241   tv[i].tv_u.tv_val = 0;
 242
 243   status = (*onload)(tv);
 244
 245   if (status != LDPS_OK)
 246     goto err;
 247
 248   *has_plugin_p = 1;
 249
 250   abfd->plugin_format = bfd_plugin_no;
 251
 252   if (!claim_file)
 253     goto err;
 254
 255   if (!try_claim (abfd))
 256     goto err;
 257
 258   abfd->plugin_format = bfd_plugin_yes;
 259
 260   return 1;
 261
 262  err:
 263   return 0;
 264 }
 265
 266 /* There may be plugin libraries in lib/bfd-plugins.  */
 267
 268 static int has_plugin = -1;
 269
 270 static const bfd_target *(*ld_plugin_object_p) (bfd *);
 271
 272 static const char *plugin_name;
 273
 274 void
 275 bfd_plugin_set_plugin (const char *p)
 276 {
 277   plugin_name = p;
 278   has_plugin = p != NULL;
 279 }
 280
 281 /* Return TRUE if a plugin library is used.  */
 282
 283 bfd_boolean
 284 bfd_plugin_specified_p (void)
 285 {
 286   return has_plugin > 0;
 287 }
 288
 289 extern const bfd_target plugin_vec;
 290
 291 /* Return TRUE if TARGET is a pointer to plugin_vec.  */
 292
 293 bfd_boolean
 294 bfd_plugin_target_p (const bfd_target *target)
 295 {
 296   return target == &plugin_vec;
 297 }
 298
 299 /* Register OBJECT_P to be used by bfd_plugin_object_p.  */
 300
 301 void
 302 register_ld_plugin_object_p (const bfd_target *(*object_p) (bfd *))
 303 {
 304   ld_plugin_object_p = object_p;
 305 }
 306
 307 static int
 308 load_plugin (bfd *abfd)
 309 {
 310   char *plugin_dir;
 311   char *p;
 312   DIR *d;
 313   struct dirent *ent;
 314   int found = 0;
 315
 316   if (!has_plugin)
 317     return found;
 318
 319   if (plugin_name)
 320     return try_load_plugin (plugin_name, abfd, &has_plugin);
 321
 322   if (plugin_program_name == NULL)
 323     return found;
 324
 325   plugin_dir = concat (BINDIR, "/../lib/bfd-plugins", NULL);
 326   p = make_relative_prefix (plugin_program_name,
 327                             BINDIR,
 328                             plugin_dir);
 329   free (plugin_dir);
 330   plugin_dir = NULL;
 331
 332   d = opendir (p);
 333   if (!d)
 334     goto out;
 335
 336   while ((ent = readdir (d)))
 337     {
 338       char *full_name;
 339       struct stat s;
 340       int valid_plugin;
 341
 342       full_name = concat (p, "/", ent->d_name, NULL);
 343       if (stat(full_name, &s) == 0 && S_ISREG (s.st_mode))
 344         found = try_load_plugin (full_name, abfd, &valid_plugin);
 345       if (has_plugin <= 0)
 346         has_plugin = valid_plugin;
 347       free (full_name);
 348       if (found)
 349         break;
 350     }
 351
 352  out:
 353   free (p);
 354   if (d)
 355     closedir (d);
 356
 357   return found;
 358 }
 359
 360
 361 static const bfd_target *
 362 bfd_plugin_object_p (bfd *abfd)
 363 {
 364   if (ld_plugin_object_p)
 365     return ld_plugin_object_p (abfd);
 366
 367   if (abfd->plugin_format == bfd_plugin_uknown && !load_plugin (abfd))
 368     return NULL;
 369
 370   return abfd->plugin_format == bfd_plugin_yes ? abfd->xvec : NULL;
 371 }
 372
 373 /* Copy any private info we understand from the input bfd
 374    to the output bfd.  */
 375
 376 static bfd_boolean
 377 bfd_plugin_bfd_copy_private_bfd_data (bfd *ibfd ATTRIBUTE_UNUSED,
 378                                       bfd *obfd ATTRIBUTE_UNUSED)
 379 {
 380   BFD_ASSERT (0);
 381   return TRUE;
 382 }
 383
 384 /* Copy any private info we understand from the input section
 385    to the output section.  */
 386
 387 static bfd_boolean
 388 bfd_plugin_bfd_copy_private_section_data (bfd *ibfd ATTRIBUTE_UNUSED,
 389                                           asection *isection ATTRIBUTE_UNUSED,
 390                                           bfd *obfd ATTRIBUTE_UNUSED,
 391                                           asection *osection ATTRIBUTE_UNUSED)
 392 {
 393   BFD_ASSERT (0);
 394   return TRUE;
 395 }
 396
 397 /* Copy any private info we understand from the input symbol
 398    to the output symbol.  */
 399
 400 static bfd_boolean
 401 bfd_plugin_bfd_copy_private_symbol_data (bfd *ibfd ATTRIBUTE_UNUSED,
 402                                          asymbol *isymbol ATTRIBUTE_UNUSED,
 403                                          bfd *obfd ATTRIBUTE_UNUSED,
 404                                          asymbol *osymbol ATTRIBUTE_UNUSED)
 405 {
 406   BFD_ASSERT (0);
 407   return TRUE;
 408 }
 409
 410 static bfd_boolean
 411 bfd_plugin_bfd_print_private_bfd_data (bfd *abfd ATTRIBUTE_UNUSED, PTR ptr ATTRIBUTE_UNUSED)
 412 {
 413   BFD_ASSERT (0);
 414   return TRUE;
 415 }
 416
 417 static char *
 418 bfd_plugin_core_file_failing_command (bfd *abfd ATTRIBUTE_UNUSED)
 419 {
 420   BFD_ASSERT (0);
 421   return NULL;
 422 }
 423
 424 static int
 425 bfd_plugin_core_file_failing_signal (bfd *abfd ATTRIBUTE_UNUSED)
 426 {
 427   BFD_ASSERT (0);
 428   return 0;
 429 }
 430
 431 static int
 432 bfd_plugin_core_file_pid (bfd *abfd ATTRIBUTE_UNUSED)
 433 {
 434   BFD_ASSERT (0);
 435   return 0;
 436 }
 437
 438 static long
 439 bfd_plugin_get_symtab_upper_bound (bfd *abfd)
 440 {
 441   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
 442   long nsyms = plugin_data->nsyms;
 443
 444   BFD_ASSERT (nsyms >= 0);
 445
 446   return ((nsyms + 1) * sizeof (asymbol *));
 447 }
 448
 449 static flagword
 450 convert_flags (const struct ld_plugin_symbol *sym)
 451 {
 452  switch (sym->def)
 453    {
 454    case LDPK_DEF:
 455    case LDPK_COMMON:
 456    case LDPK_UNDEF:
 457      return BSF_GLOBAL;
 458
 459    case LDPK_WEAKUNDEF:
 460    case LDPK_WEAKDEF:
 461      return BSF_GLOBAL | BSF_WEAK;
 462
 463    default:
 464      BFD_ASSERT (0);
 465      return 0;
 466    }
 467 }
 468
 469 static long
 470 bfd_plugin_canonicalize_symtab (bfd *abfd,
 471                                 asymbol **alocation)
 472 {
 473   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
 474   long nsyms = plugin_data->nsyms;
 475   const struct ld_plugin_symbol *syms = plugin_data->syms;
 476   static asection fake_section;
 477   static asection fake_common_section;
 478   int i;
 479
 480   fake_section.name = ".text";
 481   fake_common_section.flags = SEC_IS_COMMON;
 482
 483   for (i = 0; i < nsyms; i++)
 484     {
 485       asymbol *s = bfd_alloc (abfd, sizeof (asymbol));
 486
 487       BFD_ASSERT (s);
 488       alocation[i] = s;
 489
 490       s->the_bfd = abfd;
 491       s->name = syms[i].name;
 492       s->value = 0;
 493       s->flags = convert_flags (&syms[i]);
 494       switch (syms[i].def)
 495         {
 496         case LDPK_COMMON:
 497           s->section = &fake_common_section;
 498           break;
 499         case LDPK_UNDEF:
 500         case LDPK_WEAKUNDEF:
 501           s->section = bfd_und_section_ptr;
 502           break;
 503         case LDPK_DEF:
 504         case LDPK_WEAKDEF:
 505           s->section = &fake_section;
 506           break;
 507         default:
 508           BFD_ASSERT (0);
 509         }
 510
 511       s->udata.p = (void *) &syms[i];
 512     }
 513
 514   return nsyms;
 515 }
 516
 517 static void
 518 bfd_plugin_print_symbol (bfd *abfd ATTRIBUTE_UNUSED,
 519                          PTR afile ATTRIBUTE_UNUSED,
 520                          asymbol *symbol ATTRIBUTE_UNUSED,
 521                          bfd_print_symbol_type how ATTRIBUTE_UNUSED)
 522 {
 523   BFD_ASSERT (0);
 524 }
 525
 526 static void
 527 bfd_plugin_get_symbol_info (bfd *abfd ATTRIBUTE_UNUSED,
 528                             asymbol *symbol,
 529                             symbol_info *ret)
 530 {
 531   bfd_symbol_info (symbol, ret);
 532 }
 533
 534 /* Make an empty symbol. */
 535
 536 static asymbol *
 537 bfd_plugin_make_empty_symbol (bfd *abfd)
 538 {
 539   asymbol *new_symbol = bfd_zalloc (abfd, sizeof (asymbol));
 540   if (new_symbol == NULL)
 541     return new_symbol;
 542   new_symbol->the_bfd = abfd;
 543   return new_symbol;
 544 }
 545
 546 static int
 547 bfd_plugin_sizeof_headers (bfd *a ATTRIBUTE_UNUSED,
 548                            struct bfd_link_info *info ATTRIBUTE_UNUSED)
 549 {
 550   BFD_ASSERT (0);
 551   return 0;
 552 }
 553
 554 const bfd_target plugin_vec =
 555 {
 556   "plugin",                     /* Name.  */
 557   bfd_target_unknown_flavour,
 558   BFD_ENDIAN_LITTLE,            /* Target byte order.  */
 559   BFD_ENDIAN_LITTLE,            /* Target headers byte order.  */
 560   (HAS_RELOC | EXEC_P |         /* Object flags.  */
 561    HAS_LINENO | HAS_DEBUG |
 562    HAS_SYMS | HAS_LOCALS | DYNAMIC | WP_TEXT | D_PAGED),
 563   (SEC_CODE | SEC_DATA | SEC_ROM | SEC_HAS_CONTENTS
 564    | SEC_ALLOC | SEC_LOAD | SEC_RELOC), /* Section flags.  */
 565   0,                            /* symbol_leading_char.  */
 566   '/',                          /* ar_pad_char.  */
 567   15,                           /* ar_max_namelen.  */
 568   255,                          /* match priority.  */
 569
 570   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 571   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 572   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* data */
 573   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 574   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 575   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* hdrs */
 576
 577   {                             /* bfd_check_format.  */
 578     _bfd_dummy_target,
 579     bfd_plugin_object_p,
 580     bfd_generic_archive_p,
 581     _bfd_dummy_target
 582   },
 583   {                             /* bfd_set_format.  */
 584     bfd_false,
 585     bfd_false,
 586     _bfd_generic_mkarchive,
 587     bfd_false,
 588   },
 589   {                             /* bfd_write_contents.  */
 590     bfd_false,
 591     bfd_false,
 592     _bfd_write_archive_contents,
 593     bfd_false,
 594   },
 595
 596   BFD_JUMP_TABLE_GENERIC (bfd_plugin),
 597   BFD_JUMP_TABLE_COPY (bfd_plugin),
 598   BFD_JUMP_TABLE_CORE (bfd_plugin),
 599   BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
 600   BFD_JUMP_TABLE_SYMBOLS (bfd_plugin),
 601   BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
 602   BFD_JUMP_TABLE_WRITE (bfd_plugin),
 603   BFD_JUMP_TABLE_LINK (bfd_plugin),
 604   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 605
 606   NULL,
 607
 608   NULL                          /* backend_data.  */
 609 };
 610 #endif /* BFD_SUPPORTS_PLUGIN */