ld/plugin.c

   1 /* Plugin control for the GNU linker.
   2    Copyright 2010, 2011 Free Software Foundation, Inc.
   3
   4    This file is part of the GNU Binutils.
   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 "libiberty.h"
  23 #include "bfd.h"
  24 #include "bfdlink.h"
  25 #include "bfdver.h"
  26 #include "ld.h"
  27 #include "ldmain.h"
  28 #include "ldmisc.h"
  29 #include "ldexp.h"
  30 #include "ldlang.h"
  31 #include "ldfile.h"
  32 #include "plugin.h"
  33 #include "plugin-api.h"
  34 #include "elf-bfd.h"
  35 #include "libbfd.h"
  36 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
  37 #include <windows.h>
  38 #endif
  39
  40 /* Report plugin symbols.  */
  41 bfd_boolean report_plugin_symbols;
  42
  43 /* The suffix to append to the name of the real (claimed) object file
  44    when generating a dummy BFD to hold the IR symbols sent from the
  45    plugin.  For cosmetic use only; appears in maps, crefs etc.  */
  46 #define IRONLY_SUFFIX " (symbol from plugin)"
  47
  48 /* Stores a single argument passed to a plugin.  */
  49 typedef struct plugin_arg
  50 {
  51   struct plugin_arg *next;
  52   const char *arg;
  53 } plugin_arg_t;
  54
  55 /* Holds all details of a single plugin.  */
  56 typedef struct plugin
  57 {
  58   /* Next on the list of plugins, or NULL at end of chain.  */
  59   struct plugin *next;
  60   /* The argument string given to --plugin.  */
  61   const char *name;
  62   /* The shared library handle returned by dlopen.  */
  63   void *dlhandle;
  64   /* The list of argument string given to --plugin-opt.  */
  65   plugin_arg_t *args;
  66   /* Number of args in the list, for convenience.  */
  67   size_t n_args;
  68   /* The plugin's event handlers.  */
  69   ld_plugin_claim_file_handler claim_file_handler;
  70   ld_plugin_all_symbols_read_handler all_symbols_read_handler;
  71   ld_plugin_cleanup_handler cleanup_handler;
  72   /* TRUE if the cleanup handlers have been called.  */
  73   bfd_boolean cleanup_done;
  74 } plugin_t;
  75
  76 /* The master list of all plugins.  */
  77 static plugin_t *plugins_list = NULL;
  78
  79 /* We keep a tail pointer for easy linking on the end.  */
  80 static plugin_t **plugins_tail_chain_ptr = &plugins_list;
  81
  82 /* The last plugin added to the list, for receiving args.  */
  83 static plugin_t *last_plugin = NULL;
  84
  85 /* The tail of the arg chain of the last plugin added to the list.  */
  86 static plugin_arg_t **last_plugin_args_tail_chain_ptr = NULL;
  87
  88 /* The plugin which is currently having a callback executed.  */
  89 static plugin_t *called_plugin = NULL;
  90
  91 /* Last plugin to cause an error, if any.  */
  92 static const char *error_plugin = NULL;
  93
  94 /* State of linker "notice" interface before we poked at it.  */
  95 static bfd_boolean orig_notice_all;
  96
  97 /* Original linker callbacks, and the plugin version.  */
  98 static const struct bfd_link_callbacks *orig_callbacks;
  99 static struct bfd_link_callbacks plugin_callbacks;
 100
 101 /* Set at all symbols read time, to avoid recursively offering the plugin
 102    its own newly-added input files and libs to claim.  */
 103 bfd_boolean no_more_claiming = FALSE;
 104
 105 /* List of tags to set in the constant leading part of the tv array. */
 106 static const enum ld_plugin_tag tv_header_tags[] =
 107 {
 108   LDPT_MESSAGE,
 109   LDPT_API_VERSION,
 110   LDPT_GNU_LD_VERSION,
 111   LDPT_LINKER_OUTPUT,
 112   LDPT_OUTPUT_NAME,
 113   LDPT_REGISTER_CLAIM_FILE_HOOK,
 114   LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK,
 115   LDPT_REGISTER_CLEANUP_HOOK,
 116   LDPT_ADD_SYMBOLS,
 117   LDPT_GET_INPUT_FILE,
 118   LDPT_RELEASE_INPUT_FILE,
 119   LDPT_GET_SYMBOLS,
 120   LDPT_ADD_INPUT_FILE,
 121   LDPT_ADD_INPUT_LIBRARY,
 122   LDPT_SET_EXTRA_LIBRARY_PATH
 123 };
 124
 125 /* How many entries in the constant leading part of the tv array.  */
 126 static const size_t tv_header_size = ARRAY_SIZE (tv_header_tags);
 127
 128 /* Forward references.  */
 129 static bfd_boolean plugin_notice (struct bfd_link_info *,
 130                                   struct bfd_link_hash_entry *, bfd *,
 131                                   asection *, bfd_vma, flagword, const char *);
 132
 133 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
 134
 135 #define RTLD_NOW 0      /* Dummy value.  */
 136
 137 static void *
 138 dlopen (const char *file, int mode ATTRIBUTE_UNUSED)
 139 {
 140   return LoadLibrary (file);
 141 }
 142
 143 static void *
 144 dlsym (void *handle, const char *name)
 145 {
 146   return GetProcAddress (handle, name);
 147 }
 148
 149 static int
 150 dlclose (void *handle)
 151 {
 152   FreeLibrary (handle);
 153   return 0;
 154 }
 155
 156 #endif /* !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)  */
 157
 158 /* Helper function for exiting with error status.  */
 159 static int
 160 set_plugin_error (const char *plugin)
 161 {
 162   error_plugin = plugin;
 163   return -1;
 164 }
 165
 166 /* Test if an error occurred.  */
 167 static bfd_boolean
 168 plugin_error_p (void)
 169 {
 170   return error_plugin != NULL;
 171 }
 172
 173 /* Return name of plugin which caused an error if any.  */
 174 const char *
 175 plugin_error_plugin (void)
 176 {
 177   return error_plugin ? error_plugin : _("<no plugin>");
 178 }
 179
 180 /* Handle -plugin arg: find and load plugin, or return error.  */
 181 int
 182 plugin_opt_plugin (const char *plugin)
 183 {
 184   plugin_t *newplug;
 185
 186   newplug = xmalloc (sizeof *newplug);
 187   memset (newplug, 0, sizeof *newplug);
 188   newplug->name = plugin;
 189   newplug->dlhandle = dlopen (plugin, RTLD_NOW);
 190   if (!newplug->dlhandle)
 191     return set_plugin_error (plugin);
 192
 193   /* Chain on end, so when we run list it is in command-line order.  */
 194   *plugins_tail_chain_ptr = newplug;
 195   plugins_tail_chain_ptr = &newplug->next;
 196
 197   /* Record it as current plugin for receiving args.  */
 198   last_plugin = newplug;
 199   last_plugin_args_tail_chain_ptr = &newplug->args;
 200   return 0;
 201 }
 202
 203 /* Accumulate option arguments for last-loaded plugin, or return
 204    error if none.  */
 205 int
 206 plugin_opt_plugin_arg (const char *arg)
 207 {
 208   plugin_arg_t *newarg;
 209
 210   if (!last_plugin)
 211     return set_plugin_error (_("<no plugin>"));
 212
 213   newarg = xmalloc (sizeof *newarg);
 214   newarg->arg = arg;
 215   newarg->next = NULL;
 216
 217   /* Chain on end to preserve command-line order.  */
 218   *last_plugin_args_tail_chain_ptr = newarg;
 219   last_plugin_args_tail_chain_ptr = &newarg->next;
 220   last_plugin->n_args++;
 221   return 0;
 222 }
 223
 224 /* Create a dummy BFD.  */
 225 bfd *
 226 plugin_get_ir_dummy_bfd (const char *name, bfd *srctemplate)
 227 {
 228   bfd *abfd;
 229
 230   bfd_use_reserved_id = 1;
 231   abfd = bfd_create (concat (name, IRONLY_SUFFIX, (const char *) NULL),
 232                      srctemplate);
 233   if (abfd != NULL)
 234     {
 235       abfd->flags |= BFD_LINKER_CREATED | BFD_PLUGIN;
 236       bfd_set_arch_info (abfd, bfd_get_arch_info (srctemplate));
 237       bfd_set_gp_size (abfd, bfd_get_gp_size (srctemplate));
 238       if (bfd_make_writable (abfd)
 239           && bfd_copy_private_bfd_data (srctemplate, abfd))
 240         {
 241           flagword flags;
 242
 243           /* Create sections to own the symbols.  */
 244           flags = (SEC_CODE | SEC_HAS_CONTENTS | SEC_READONLY
 245                    | SEC_ALLOC | SEC_LOAD | SEC_KEEP | SEC_EXCLUDE);
 246           if (bfd_make_section_anyway_with_flags (abfd, ".text", flags))
 247             return abfd;
 248         }
 249     }
 250   einfo (_("could not create dummy IR bfd: %F%E\n"));
 251   return NULL;
 252 }
 253
 254 /* Check if the BFD passed in is an IR dummy object file.  */
 255 static bfd_boolean
 256 is_ir_dummy_bfd (const bfd *abfd)
 257 {
 258   /* ABFD can sometimes legitimately be NULL, e.g. when called from one
 259      of the linker callbacks for a symbol in the *ABS* or *UND* sections.
 260      Likewise, the usrdata field may be NULL if ABFD was added by the
 261      backend without a corresponding input statement, as happens e.g.
 262      when processing DT_NEEDED dependencies.  */
 263   return (abfd
 264           && abfd->usrdata
 265           && ((lang_input_statement_type *)(abfd->usrdata))->claimed);
 266 }
 267
 268 /* Helpers to convert between BFD and GOLD symbol formats.  */
 269 static enum ld_plugin_status
 270 asymbol_from_plugin_symbol (bfd *abfd, asymbol *asym,
 271                             const struct ld_plugin_symbol *ldsym)
 272 {
 273   flagword flags = BSF_NO_FLAGS;
 274   struct bfd_section *section;
 275
 276   asym->the_bfd = abfd;
 277   asym->name = (ldsym->version
 278                 ? concat (ldsym->name, "@", ldsym->version, (const char *) NULL)
 279                 : ldsym->name);
 280   asym->value = 0;
 281   switch (ldsym->def)
 282     {
 283     case LDPK_WEAKDEF:
 284       flags = BSF_WEAK;
 285       /* FALLTHRU */
 286     case LDPK_DEF:
 287       flags |= BSF_GLOBAL;
 288       section = bfd_get_section_by_name (abfd, ".text");
 289       break;
 290
 291     case LDPK_WEAKUNDEF:
 292       flags = BSF_WEAK;
 293       /* FALLTHRU */
 294     case LDPK_UNDEF:
 295       section = bfd_und_section_ptr;
 296       break;
 297
 298     case LDPK_COMMON:
 299       flags = BSF_GLOBAL;
 300       section = bfd_com_section_ptr;
 301       asym->value = ldsym->size;
 302       /* For ELF targets, set alignment of common symbol to 1.  */
 303       if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 304         {
 305           ((elf_symbol_type *) asym)->internal_elf_sym.st_shndx = SHN_COMMON;
 306           ((elf_symbol_type *) asym)->internal_elf_sym.st_value = 1;
 307         }
 308       break;
 309
 310     default:
 311       return LDPS_ERR;
 312     }
 313   asym->flags = flags;
 314   asym->section = section;
 315
 316   /* Visibility only applies on ELF targets.  */
 317   if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 318     {
 319       elf_symbol_type *elfsym = elf_symbol_from (abfd, asym);
 320       unsigned char visibility;
 321
 322       if (!elfsym)
 323         einfo (_("%P%F: %s: non-ELF symbol in ELF BFD!\n"), asym->name);
 324       switch (ldsym->visibility)
 325         {
 326         default:
 327           einfo (_("%P%F: unknown ELF symbol visibility: %d!\n"),
 328                  ldsym->visibility);
 329         case LDPV_DEFAULT:
 330           visibility = STV_DEFAULT;
 331           break;
 332         case LDPV_PROTECTED:
 333           visibility = STV_PROTECTED;
 334           break;
 335         case LDPV_INTERNAL:
 336           visibility = STV_INTERNAL;
 337           break;
 338         case LDPV_HIDDEN:
 339           visibility = STV_HIDDEN;
 340           break;
 341         }
 342       elfsym->internal_elf_sym.st_other
 343         = (visibility | (elfsym->internal_elf_sym.st_other
 344                          & ~ELF_ST_VISIBILITY (-1)));
 345     }
 346
 347   return LDPS_OK;
 348 }
 349
 350 /* Register a claim-file handler.  */
 351 static enum ld_plugin_status
 352 register_claim_file (ld_plugin_claim_file_handler handler)
 353 {
 354   ASSERT (called_plugin);
 355   called_plugin->claim_file_handler = handler;
 356   return LDPS_OK;
 357 }
 358
 359 /* Register an all-symbols-read handler.  */
 360 static enum ld_plugin_status
 361 register_all_symbols_read (ld_plugin_all_symbols_read_handler handler)
 362 {
 363   ASSERT (called_plugin);
 364   called_plugin->all_symbols_read_handler = handler;
 365   return LDPS_OK;
 366 }
 367
 368 /* Register a cleanup handler.  */
 369 static enum ld_plugin_status
 370 register_cleanup (ld_plugin_cleanup_handler handler)
 371 {
 372   ASSERT (called_plugin);
 373   called_plugin->cleanup_handler = handler;
 374   return LDPS_OK;
 375 }
 376
 377 /* Add symbols from a plugin-claimed input file.  */
 378 static enum ld_plugin_status
 379 add_symbols (void *handle, int nsyms, const struct ld_plugin_symbol *syms)
 380 {
 381   asymbol **symptrs;
 382   bfd *abfd = handle;
 383   int n;
 384   ASSERT (called_plugin);
 385   symptrs = xmalloc (nsyms * sizeof *symptrs);
 386   for (n = 0; n < nsyms; n++)
 387     {
 388       enum ld_plugin_status rv;
 389       asymbol *bfdsym;
 390
 391       if (syms[n].comdat_key)
 392         {
 393           struct already_linked linked;
 394           linked.comdat_key = xstrdup (syms[n].comdat_key);
 395           linked.u.abfd = abfd;
 396           bfd_section_already_linked (abfd, &linked, &link_info);
 397         }
 398       bfdsym = bfd_make_empty_symbol (abfd);
 399       symptrs[n] = bfdsym;
 400       rv = asymbol_from_plugin_symbol (abfd, bfdsym, syms + n);
 401       if (rv != LDPS_OK)
 402         return rv;
 403     }
 404   bfd_set_symtab (abfd, symptrs, nsyms);
 405   return LDPS_OK;
 406 }
 407
 408 /* Get the input file information with an open (possibly re-opened)
 409    file descriptor.  */
 410 static enum ld_plugin_status
 411 get_input_file (const void *handle, struct ld_plugin_input_file *file)
 412 {
 413   ASSERT (called_plugin);
 414   handle = handle;
 415   file = file;
 416   return LDPS_ERR;
 417 }
 418
 419 /* Release the input file.  */
 420 static enum ld_plugin_status
 421 release_input_file (const void *handle)
 422 {
 423   ASSERT (called_plugin);
 424   handle = handle;
 425   return LDPS_ERR;
 426 }
 427
 428 /* Return TRUE if a defined symbol might be reachable from outside the
 429    universe of claimed objects.  */
 430 static inline bfd_boolean
 431 is_visible_from_outside (struct ld_plugin_symbol *lsym, asection *section,
 432                          struct bfd_link_hash_entry *blhe)
 433 {
 434   struct bfd_sym_chain *sym;
 435
 436   /* Section's owner may be NULL if it is the absolute
 437      section, fortunately is_ir_dummy_bfd handles that.  */
 438   if (!is_ir_dummy_bfd (section->owner))
 439     return TRUE;
 440   if (link_info.relocatable)
 441     return TRUE;
 442   if (link_info.export_dynamic || link_info.shared)
 443     {
 444       /* Only ELF symbols really have visibility.  */
 445       if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
 446         {
 447           struct elf_link_hash_entry *el = (struct elf_link_hash_entry *)blhe;
 448           int vis = ELF_ST_VISIBILITY (el->other);
 449           return vis == STV_DEFAULT || vis == STV_PROTECTED;
 450         }
 451       /* On non-ELF targets, we can safely make inferences by considering
 452          what visibility the plugin would have liked to apply when it first
 453          sent us the symbol.  During ELF symbol processing, visibility only
 454          ever becomes more restrictive, not less, when symbols are merged,
 455          so this is a conservative estimate; it may give false positives,
 456          declaring something visible from outside when it in fact would
 457          not have been, but this will only lead to missed optimisation
 458          opportunities during LTRANS at worst; it will not give false
 459          negatives, which can lead to the disastrous conclusion that the
 460          related symbol is IRONLY.  (See GCC PR46319 for an example.)  */
 461       return (lsym->visibility == LDPV_DEFAULT
 462               || lsym->visibility == LDPV_PROTECTED);
 463     }
 464
 465   for (sym = &entry_symbol; sym != NULL; sym = sym->next)
 466     if (sym->name
 467         && strcmp (sym->name, blhe->root.string) == 0)
 468       return TRUE;
 469
 470   return FALSE;
 471 }
 472
 473 /* Get the symbol resolution info for a plugin-claimed input file.  */
 474 static enum ld_plugin_status
 475 get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
 476 {
 477   const bfd *abfd = handle;
 478   int n;
 479   ASSERT (called_plugin);
 480   for (n = 0; n < nsyms; n++)
 481     {
 482       struct bfd_link_hash_entry *blhe;
 483       bfd_boolean ironly;
 484       asection *owner_sec;
 485       if (syms[n].def != LDPK_UNDEF)
 486         blhe = bfd_link_hash_lookup (link_info.hash, syms[n].name,
 487                                      FALSE, FALSE, TRUE);
 488       else
 489         blhe = bfd_wrapped_link_hash_lookup (link_info.output_bfd, &link_info,
 490                                              syms[n].name, FALSE, FALSE, TRUE);
 491       if (!blhe)
 492         {
 493           syms[n].resolution = LDPR_UNKNOWN;
 494           goto report_symbol;
 495         }
 496
 497       /* Determine resolution from blhe type and symbol's original type.  */
 498       if (blhe->type == bfd_link_hash_undefined
 499           || blhe->type == bfd_link_hash_undefweak)
 500         {
 501           syms[n].resolution = LDPR_UNDEF;
 502           goto report_symbol;
 503         }
 504       if (blhe->type != bfd_link_hash_defined
 505           && blhe->type != bfd_link_hash_defweak
 506           && blhe->type != bfd_link_hash_common)
 507         {
 508           /* We should not have a new, indirect or warning symbol here.  */
 509           einfo ("%P%F: %s: plugin symbol table corrupt (sym type %d)\n",
 510                  called_plugin->name, blhe->type);
 511         }
 512
 513       /* Find out which section owns the symbol.  Since it's not undef,
 514          it must have an owner; if it's not a common symbol, both defs
 515          and weakdefs keep it in the same place. */
 516       owner_sec = (blhe->type == bfd_link_hash_common
 517                    ? blhe->u.c.p->section
 518                    : blhe->u.def.section);
 519
 520       /* We need to know if the sym is referenced from non-IR files.  Or
 521          even potentially-referenced, perhaps in a future final link if
 522          this is a partial one, perhaps dynamically at load-time if the
 523          symbol is externally visible.  */
 524       ironly = !(blhe->non_ir_ref
 525                  || is_visible_from_outside (&syms[n], owner_sec, blhe));
 526
 527       /* If it was originally undefined or common, then it has been
 528          resolved; determine how.  */
 529       if (syms[n].def == LDPK_UNDEF
 530           || syms[n].def == LDPK_WEAKUNDEF
 531           || syms[n].def == LDPK_COMMON)
 532         {
 533           if (owner_sec->owner == link_info.output_bfd)
 534             syms[n].resolution = LDPR_RESOLVED_EXEC;
 535           else if (owner_sec->owner == abfd)
 536             syms[n].resolution = (ironly
 537                                   ? LDPR_PREVAILING_DEF_IRONLY
 538                                   : LDPR_PREVAILING_DEF);
 539           else if (is_ir_dummy_bfd (owner_sec->owner))
 540             syms[n].resolution = LDPR_RESOLVED_IR;
 541           else if (owner_sec->owner != NULL
 542                    && (owner_sec->owner->flags & DYNAMIC) != 0)
 543             syms[n].resolution =  LDPR_RESOLVED_DYN;
 544           else
 545             syms[n].resolution = LDPR_RESOLVED_EXEC;
 546           goto report_symbol;
 547         }
 548
 549       /* Was originally def, or weakdef.  Does it prevail?  If the
 550          owner is the original dummy bfd that supplied it, then this
 551          is the definition that has prevailed.  */
 552       if (owner_sec->owner == link_info.output_bfd)
 553         syms[n].resolution = LDPR_PREEMPTED_REG;
 554       else if (owner_sec->owner == abfd)
 555         {
 556           syms[n].resolution = (ironly
 557                                 ? LDPR_PREVAILING_DEF_IRONLY
 558                                 : LDPR_PREVAILING_DEF);
 559           goto report_symbol;
 560         }
 561
 562       /* Was originally def, weakdef, or common, but has been pre-empted.  */
 563       syms[n].resolution = (is_ir_dummy_bfd (owner_sec->owner)
 564                             ? LDPR_PREEMPTED_IR
 565                             : LDPR_PREEMPTED_REG);
 566
 567     report_symbol:
 568       if (report_plugin_symbols)
 569         einfo (_("%P: %B: symbol `%s' "
 570                  "definition: %d, visibility: %d, resolution: %d\n"),
 571                abfd, syms[n].name,
 572                syms[n].def, syms[n].visibility, syms[n].resolution);
 573     }
 574   return LDPS_OK;
 575 }
 576
 577 /* Add a new (real) input file generated by a plugin.  */
 578 static enum ld_plugin_status
 579 add_input_file (const char *pathname)
 580 {
 581   ASSERT (called_plugin);
 582   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_file_enum,
 583                             NULL))
 584     return LDPS_ERR;
 585   return LDPS_OK;
 586 }
 587
 588 /* Add a new (real) library required by a plugin.  */
 589 static enum ld_plugin_status
 590 add_input_library (const char *pathname)
 591 {
 592   ASSERT (called_plugin);
 593   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_l_enum,
 594                             NULL))
 595     return LDPS_ERR;
 596   return LDPS_OK;
 597 }
 598
 599 /* Set the extra library path to be used by libraries added via
 600    add_input_library.  */
 601 static enum ld_plugin_status
 602 set_extra_library_path (const char *path)
 603 {
 604   ASSERT (called_plugin);
 605   ldfile_add_library_path (xstrdup (path), FALSE);
 606   return LDPS_OK;
 607 }
 608
 609 /* Issue a diagnostic message from a plugin.  */
 610 static enum ld_plugin_status
 611 message (int level, const char *format, ...)
 612 {
 613   va_list args;
 614   va_start (args, format);
 615
 616   switch (level)
 617     {
 618     case LDPL_INFO:
 619       vfinfo (stdout, format, args, FALSE);
 620       putchar ('\n');
 621       break;
 622     case LDPL_WARNING:
 623       vfinfo (stdout, format, args, TRUE);
 624       putchar ('\n');
 625       break;
 626     case LDPL_FATAL:
 627     case LDPL_ERROR:
 628     default:
 629       {
 630         char *newfmt = ACONCAT ((level == LDPL_FATAL ? "%P%F: " : "%P%X: ",
 631                                  format, "\n", (const char *) NULL));
 632         fflush (stdout);
 633         vfinfo (stderr, newfmt, args, TRUE);
 634         fflush (stderr);
 635       }
 636       break;
 637     }
 638
 639   va_end (args);
 640   return LDPS_OK;
 641 }
 642
 643 /* Helper to size leading part of tv array and set it up. */
 644 static size_t
 645 set_tv_header (struct ld_plugin_tv *tv)
 646 {
 647   size_t i;
 648
 649   /* Version info.  */
 650   static const unsigned int major = (unsigned)(BFD_VERSION / 100000000UL);
 651   static const unsigned int minor = (unsigned)(BFD_VERSION / 1000000UL) % 100;
 652
 653   if (!tv)
 654     return tv_header_size;
 655
 656   for (i = 0; i < tv_header_size; i++)
 657     {
 658       tv[i].tv_tag = tv_header_tags[i];
 659 #define TVU(x) tv[i].tv_u.tv_ ## x
 660       switch (tv[i].tv_tag)
 661         {
 662         case LDPT_MESSAGE:
 663           TVU(message) = message;
 664           break;
 665         case LDPT_API_VERSION:
 666           TVU(val) = LD_PLUGIN_API_VERSION;
 667           break;
 668         case LDPT_GNU_LD_VERSION:
 669           TVU(val) = major * 100 + minor;
 670           break;
 671         case LDPT_LINKER_OUTPUT:
 672           TVU(val) = (link_info.relocatable
 673                       ? LDPO_REL
 674                       : (link_info.shared ? LDPO_DYN : LDPO_EXEC));
 675           break;
 676         case LDPT_OUTPUT_NAME:
 677           TVU(string) = output_filename;
 678           break;
 679         case LDPT_REGISTER_CLAIM_FILE_HOOK:
 680           TVU(register_claim_file) = register_claim_file;
 681           break;
 682         case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK:
 683           TVU(register_all_symbols_read) = register_all_symbols_read;
 684           break;
 685         case LDPT_REGISTER_CLEANUP_HOOK:
 686           TVU(register_cleanup) = register_cleanup;
 687           break;
 688         case LDPT_ADD_SYMBOLS:
 689           TVU(add_symbols) = add_symbols;
 690           break;
 691         case LDPT_GET_INPUT_FILE:
 692           TVU(get_input_file) = get_input_file;
 693           break;
 694         case LDPT_RELEASE_INPUT_FILE:
 695           TVU(release_input_file) = release_input_file;
 696           break;
 697         case LDPT_GET_SYMBOLS:
 698           TVU(get_symbols) = get_symbols;
 699           break;
 700         case LDPT_ADD_INPUT_FILE:
 701           TVU(add_input_file) = add_input_file;
 702           break;
 703         case LDPT_ADD_INPUT_LIBRARY:
 704           TVU(add_input_library) = add_input_library;
 705           break;
 706         case LDPT_SET_EXTRA_LIBRARY_PATH:
 707           TVU(set_extra_library_path) = set_extra_library_path;
 708           break;
 709         default:
 710           /* Added a new entry to the array without adding
 711              a new case to set up its value is a bug.  */
 712           FAIL ();
 713         }
 714 #undef TVU
 715     }
 716   return tv_header_size;
 717 }
 718
 719 /* Append the per-plugin args list and trailing LDPT_NULL to tv.  */
 720 static void
 721 set_tv_plugin_args (plugin_t *plugin, struct ld_plugin_tv *tv)
 722 {
 723   plugin_arg_t *arg = plugin->args;
 724   while (arg)
 725     {
 726       tv->tv_tag = LDPT_OPTION;
 727       tv->tv_u.tv_string = arg->arg;
 728       arg = arg->next;
 729       tv++;
 730     }
 731   tv->tv_tag = LDPT_NULL;
 732   tv->tv_u.tv_val = 0;
 733 }
 734
 735 /* Return true if any plugins are active this run.  Only valid
 736    after options have been processed.  */
 737 bfd_boolean
 738 plugin_active_plugins_p (void)
 739 {
 740   return plugins_list != NULL;
 741 }
 742
 743 /* Load up and initialise all plugins after argument parsing.  */
 744 int
 745 plugin_load_plugins (void)
 746 {
 747   struct ld_plugin_tv *my_tv;
 748   unsigned int max_args = 0;
 749   plugin_t *curplug = plugins_list;
 750
 751   /* If there are no plugins, we need do nothing this run.  */
 752   if (!curplug)
 753     return 0;
 754
 755   /* First pass over plugins to find max # args needed so that we
 756      can size and allocate the tv array.  */
 757   while (curplug)
 758     {
 759       if (curplug->n_args > max_args)
 760         max_args = curplug->n_args;
 761       curplug = curplug->next;
 762     }
 763
 764   /* Allocate tv array and initialise constant part.  */
 765   my_tv = xmalloc ((max_args + 1 + tv_header_size) * sizeof *my_tv);
 766   set_tv_header (my_tv);
 767
 768   /* Pass over plugins again, activating them.  */
 769   curplug = plugins_list;
 770   while (curplug)
 771     {
 772       enum ld_plugin_status rv;
 773       ld_plugin_onload onloadfn = dlsym (curplug->dlhandle, "onload");
 774       if (!onloadfn)
 775         onloadfn = dlsym (curplug->dlhandle, "_onload");
 776       if (!onloadfn)
 777         return set_plugin_error (curplug->name);
 778       set_tv_plugin_args (curplug, &my_tv[tv_header_size]);
 779       called_plugin = curplug;
 780       rv = (*onloadfn) (my_tv);
 781       called_plugin = NULL;
 782       if (rv != LDPS_OK)
 783         return set_plugin_error (curplug->name);
 784       curplug = curplug->next;
 785     }
 786
 787   /* Since plugin(s) inited ok, assume they're going to want symbol
 788      resolutions, which needs us to track which symbols are referenced
 789      by non-IR files using the linker's notice callback.  */
 790   orig_notice_all = link_info.notice_all;
 791   orig_callbacks = link_info.callbacks;
 792   plugin_callbacks = *orig_callbacks;
 793   plugin_callbacks.notice = &plugin_notice;
 794   link_info.notice_all = TRUE;
 795   link_info.callbacks = &plugin_callbacks;
 796
 797   return 0;
 798 }
 799
 800 /* Call 'claim file' hook for all plugins.  */
 801 static int
 802 plugin_call_claim_file (const struct ld_plugin_input_file *file, int *claimed)
 803 {
 804   plugin_t *curplug = plugins_list;
 805   *claimed = FALSE;
 806   if (no_more_claiming)
 807     return 0;
 808   while (curplug && !*claimed)
 809     {
 810       if (curplug->claim_file_handler)
 811         {
 812           enum ld_plugin_status rv;
 813           called_plugin = curplug;
 814           rv = (*curplug->claim_file_handler) (file, claimed);
 815           called_plugin = NULL;
 816           if (rv != LDPS_OK)
 817             set_plugin_error (curplug->name);
 818         }
 819       curplug = curplug->next;
 820     }
 821   return plugin_error_p () ? -1 : 0;
 822 }
 823
 824 void
 825 plugin_maybe_claim (struct ld_plugin_input_file *file,
 826                     lang_input_statement_type *entry)
 827 {
 828   int claimed = 0;
 829
 830   /* We create a dummy BFD, initially empty, to house whatever symbols
 831      the plugin may want to add.  */
 832   file->handle = plugin_get_ir_dummy_bfd (entry->the_bfd->filename,
 833                                           entry->the_bfd);
 834   if (plugin_call_claim_file (file, &claimed))
 835     einfo (_("%P%F: %s: plugin reported error claiming file\n"),
 836            plugin_error_plugin ());
 837   /* fd belongs to us, not the plugin; but we don't need it.  */
 838   close (file->fd);
 839   if (claimed)
 840     {
 841       /* Discard the real file's BFD and substitute the dummy one.  */
 842
 843       /* BFD archive handling caches elements so we can't call
 844          bfd_close for archives.  */
 845       if (entry->the_bfd->my_archive == NULL)
 846         bfd_close (entry->the_bfd);
 847       entry->the_bfd = file->handle;
 848       entry->claimed = TRUE;
 849       bfd_make_readable (entry->the_bfd);
 850     }
 851   else
 852     {
 853       /* If plugin didn't claim the file, we don't need the dummy bfd.
 854          Can't avoid speculatively creating it, alas.  */
 855       bfd_close_all_done (file->handle);
 856       entry->claimed = FALSE;
 857     }
 858 }
 859
 860 /* Call 'all symbols read' hook for all plugins.  */
 861 int
 862 plugin_call_all_symbols_read (void)
 863 {
 864   plugin_t *curplug = plugins_list;
 865
 866   /* Disable any further file-claiming.  */
 867   no_more_claiming = TRUE;
 868
 869   while (curplug)
 870     {
 871       if (curplug->all_symbols_read_handler)
 872         {
 873           enum ld_plugin_status rv;
 874           called_plugin = curplug;
 875           rv = (*curplug->all_symbols_read_handler) ();
 876           called_plugin = NULL;
 877           if (rv != LDPS_OK)
 878             set_plugin_error (curplug->name);
 879         }
 880       curplug = curplug->next;
 881     }
 882   return plugin_error_p () ? -1 : 0;
 883 }
 884
 885 /* Call 'cleanup' hook for all plugins at exit.  */
 886 void
 887 plugin_call_cleanup (void)
 888 {
 889   plugin_t *curplug = plugins_list;
 890   while (curplug)
 891     {
 892       if (curplug->cleanup_handler && !curplug->cleanup_done)
 893         {
 894           enum ld_plugin_status rv;
 895           curplug->cleanup_done = TRUE;
 896           called_plugin = curplug;
 897           rv = (*curplug->cleanup_handler) ();
 898           called_plugin = NULL;
 899           if (rv != LDPS_OK)
 900             set_plugin_error (curplug->name);
 901           dlclose (curplug->dlhandle);
 902         }
 903       curplug = curplug->next;
 904     }
 905   if (plugin_error_p ())
 906     info_msg (_("%P: %s: error in plugin cleanup (ignored)\n"),
 907               plugin_error_plugin ());
 908 }
 909
 910 /* To determine which symbols should be resolved LDPR_PREVAILING_DEF
 911    and which LDPR_PREVAILING_DEF_IRONLY, we notice all the symbols as
 912    the linker adds them to the linker hash table.  Mark those
 913    referenced from a non-IR file with non_ir_ref.  We have to
 914    notice_all symbols, because we won't necessarily know until later
 915    which ones will be contributed by IR files.  */
 916 static bfd_boolean
 917 plugin_notice (struct bfd_link_info *info,
 918                struct bfd_link_hash_entry *h,
 919                bfd *abfd,
 920                asection *section,
 921                bfd_vma value,
 922                flagword flags,
 923                const char *string)
 924 {
 925   if (h != NULL)
 926     {
 927       bfd *sym_bfd;
 928
 929       /* No further processing if this def/ref is from an IR dummy BFD.  */
 930       if (is_ir_dummy_bfd (abfd))
 931         return TRUE;
 932
 933       /* Making an indirect symbol counts as a reference unless this
 934          is a brand new symbol.  */
 935       if (bfd_is_ind_section (section)
 936           || (flags & BSF_INDIRECT) != 0)
 937         {
 938           if (h->type != bfd_link_hash_new)
 939             {
 940               struct bfd_link_hash_entry *inh;
 941
 942               h->non_ir_ref = TRUE;
 943               inh = bfd_wrapped_link_hash_lookup (abfd, info, string, FALSE,
 944                                                   FALSE, FALSE);
 945               if (inh != NULL)
 946                 inh->non_ir_ref = TRUE;
 947             }
 948         }
 949
 950       /* Nothing to do here for warning symbols.  */
 951       else if ((flags & BSF_WARNING) != 0)
 952         ;
 953
 954       /* Nothing to do here for constructor symbols.  */
 955       else if ((flags & BSF_CONSTRUCTOR) != 0)
 956         ;
 957
 958       /* If this is a ref, set non_ir_ref.  */
 959       else if (bfd_is_und_section (section))
 960         h->non_ir_ref = TRUE;
 961
 962       /* Otherwise, it must be a new def.  Ensure any symbol defined
 963          in an IR dummy BFD takes on a new value from a real BFD.
 964          Weak symbols are not normally overridden by a new weak
 965          definition, and strong symbols will normally cause multiple
 966          definition errors.  Avoid this by making the symbol appear
 967          to be undefined.  */
 968       else if (((h->type == bfd_link_hash_defweak
 969                  || h->type == bfd_link_hash_defined)
 970                 && is_ir_dummy_bfd (sym_bfd = h->u.def.section->owner))
 971                || (h->type == bfd_link_hash_common
 972                    && is_ir_dummy_bfd (sym_bfd = h->u.c.p->section->owner)))
 973         {
 974           h->type = bfd_link_hash_undefweak;
 975           h->u.undef.abfd = sym_bfd;
 976         }
 977     }
 978
 979   /* Continue with cref/nocrossref/trace-sym processing.  */
 980   if (h == NULL
 981       || orig_notice_all
 982       || (info->notice_hash != NULL
 983           && bfd_hash_lookup (info->notice_hash, h->root.string,
 984                               FALSE, FALSE) != NULL))
 985     return (*orig_callbacks->notice) (info, h,
 986                                       abfd, section, value, flags, string);
 987   return TRUE;
 988 }