ld/plugin.c

   1 /* Plugin control for the GNU linker.
   2    Copyright 2010, 2011, 2012 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 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
  36 #include <windows.h>
  37 #endif
  38
  39 /* Report plugin symbols.  */
  40 bfd_boolean report_plugin_symbols;
  41
  42 /* The suffix to append to the name of the real (claimed) object file
  43    when generating a dummy BFD to hold the IR symbols sent from the
  44    plugin.  For cosmetic use only; appears in maps, crefs etc.  */
  45 #define IRONLY_SUFFIX " (symbol from plugin)"
  46
  47 /* Stores a single argument passed to a plugin.  */
  48 typedef struct plugin_arg
  49 {
  50   struct plugin_arg *next;
  51   const char *arg;
  52 } plugin_arg_t;
  53
  54 /* Holds all details of a single plugin.  */
  55 typedef struct plugin
  56 {
  57   /* Next on the list of plugins, or NULL at end of chain.  */
  58   struct plugin *next;
  59   /* The argument string given to --plugin.  */
  60   const char *name;
  61   /* The shared library handle returned by dlopen.  */
  62   void *dlhandle;
  63   /* The list of argument string given to --plugin-opt.  */
  64   plugin_arg_t *args;
  65   /* Number of args in the list, for convenience.  */
  66   size_t n_args;
  67   /* The plugin's event handlers.  */
  68   ld_plugin_claim_file_handler claim_file_handler;
  69   ld_plugin_all_symbols_read_handler all_symbols_read_handler;
  70   ld_plugin_cleanup_handler cleanup_handler;
  71   /* TRUE if the cleanup handlers have been called.  */
  72   bfd_boolean cleanup_done;
  73 } plugin_t;
  74
  75 /* The master list of all plugins.  */
  76 static plugin_t *plugins_list = NULL;
  77
  78 /* We keep a tail pointer for easy linking on the end.  */
  79 static plugin_t **plugins_tail_chain_ptr = &plugins_list;
  80
  81 /* The last plugin added to the list, for receiving args.  */
  82 static plugin_t *last_plugin = NULL;
  83
  84 /* The tail of the arg chain of the last plugin added to the list.  */
  85 static plugin_arg_t **last_plugin_args_tail_chain_ptr = NULL;
  86
  87 /* The plugin which is currently having a callback executed.  */
  88 static plugin_t *called_plugin = NULL;
  89
  90 /* Last plugin to cause an error, if any.  */
  91 static const char *error_plugin = NULL;
  92
  93 /* State of linker "notice" interface before we poked at it.  */
  94 static bfd_boolean orig_notice_all;
  95
  96 /* Original linker callbacks, and the plugin version.  */
  97 static const struct bfd_link_callbacks *orig_callbacks;
  98 static struct bfd_link_callbacks plugin_callbacks;
  99
 100 /* Set at all symbols read time, to avoid recursively offering the plugin
 101    its own newly-added input files and libs to claim.  */
 102 bfd_boolean no_more_claiming = FALSE;
 103
 104 /* List of tags to set in the constant leading part of the tv array. */
 105 static const enum ld_plugin_tag tv_header_tags[] =
 106 {
 107   LDPT_MESSAGE,
 108   LDPT_API_VERSION,
 109   LDPT_GNU_LD_VERSION,
 110   LDPT_LINKER_OUTPUT,
 111   LDPT_OUTPUT_NAME,
 112   LDPT_REGISTER_CLAIM_FILE_HOOK,
 113   LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK,
 114   LDPT_REGISTER_CLEANUP_HOOK,
 115   LDPT_ADD_SYMBOLS,
 116   LDPT_GET_INPUT_FILE,
 117   LDPT_RELEASE_INPUT_FILE,
 118   LDPT_GET_SYMBOLS,
 119   LDPT_GET_SYMBOLS_V2,
 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 #ifndef HAVE_DLFCN_H
 159 static const char *
 160 dlerror (void)
 161 {
 162   return "";
 163 }
 164 #endif
 165
 166 /* Helper function for exiting with error status.  */
 167 static int
 168 set_plugin_error (const char *plugin)
 169 {
 170   error_plugin = plugin;
 171   return -1;
 172 }
 173
 174 /* Test if an error occurred.  */
 175 static bfd_boolean
 176 plugin_error_p (void)
 177 {
 178   return error_plugin != NULL;
 179 }
 180
 181 /* Return name of plugin which caused an error if any.  */
 182 const char *
 183 plugin_error_plugin (void)
 184 {
 185   return error_plugin ? error_plugin : _("<no plugin>");
 186 }
 187
 188 /* Handle -plugin arg: find and load plugin, or return error.  */
 189 void
 190 plugin_opt_plugin (const char *plugin)
 191 {
 192   plugin_t *newplug;
 193
 194   newplug = xmalloc (sizeof *newplug);
 195   memset (newplug, 0, sizeof *newplug);
 196   newplug->name = plugin;
 197   newplug->dlhandle = dlopen (plugin, RTLD_NOW);
 198   if (!newplug->dlhandle)
 199     einfo (_("%P%F: %s: error loading plugin: %s\n"), plugin, dlerror ());
 200
 201   /* Chain on end, so when we run list it is in command-line order.  */
 202   *plugins_tail_chain_ptr = newplug;
 203   plugins_tail_chain_ptr = &newplug->next;
 204
 205   /* Record it as current plugin for receiving args.  */
 206   last_plugin = newplug;
 207   last_plugin_args_tail_chain_ptr = &newplug->args;
 208 }
 209
 210 /* Accumulate option arguments for last-loaded plugin, or return
 211    error if none.  */
 212 int
 213 plugin_opt_plugin_arg (const char *arg)
 214 {
 215   plugin_arg_t *newarg;
 216
 217   if (!last_plugin)
 218     return set_plugin_error (_("<no plugin>"));
 219
 220   newarg = xmalloc (sizeof *newarg);
 221   newarg->arg = arg;
 222   newarg->next = NULL;
 223
 224   /* Chain on end to preserve command-line order.  */
 225   *last_plugin_args_tail_chain_ptr = newarg;
 226   last_plugin_args_tail_chain_ptr = &newarg->next;
 227   last_plugin->n_args++;
 228   return 0;
 229 }
 230
 231 /* Create a dummy BFD.  */
 232 bfd *
 233 plugin_get_ir_dummy_bfd (const char *name, bfd *srctemplate)
 234 {
 235   bfd *abfd;
 236
 237   bfd_use_reserved_id = 1;
 238   abfd = bfd_create (concat (name, IRONLY_SUFFIX, (const char *) NULL),
 239                      srctemplate);
 240   if (abfd != NULL)
 241     {
 242       abfd->flags |= BFD_LINKER_CREATED | BFD_PLUGIN;
 243       bfd_set_arch_info (abfd, bfd_get_arch_info (srctemplate));
 244       bfd_set_gp_size (abfd, bfd_get_gp_size (srctemplate));
 245       if (bfd_make_writable (abfd)
 246           && bfd_copy_private_bfd_data (srctemplate, abfd))
 247         {
 248           flagword flags;
 249
 250           /* Create section to own the symbols.  */
 251           flags = (SEC_CODE | SEC_HAS_CONTENTS | SEC_READONLY
 252                    | SEC_ALLOC | SEC_LOAD | SEC_KEEP | SEC_EXCLUDE);
 253           if (bfd_make_section_anyway_with_flags (abfd, ".text", flags))
 254             return abfd;
 255         }
 256     }
 257   einfo (_("could not create dummy IR bfd: %F%E\n"));
 258   return NULL;
 259 }
 260
 261 /* Check if the BFD passed in is an IR dummy object file.  */
 262 static bfd_boolean
 263 is_ir_dummy_bfd (const bfd *abfd)
 264 {
 265   /* ABFD can sometimes legitimately be NULL, e.g. when called from one
 266      of the linker callbacks for a symbol in the *ABS* or *UND* sections.
 267      Likewise, the usrdata field may be NULL if ABFD was added by the
 268      backend without a corresponding input statement, as happens e.g.
 269      when processing DT_NEEDED dependencies.  */
 270   return (abfd
 271           && abfd->usrdata
 272           && ((lang_input_statement_type *)(abfd->usrdata))->flags.claimed);
 273 }
 274
 275 /* Helpers to convert between BFD and GOLD symbol formats.  */
 276 static enum ld_plugin_status
 277 asymbol_from_plugin_symbol (bfd *abfd, asymbol *asym,
 278                             const struct ld_plugin_symbol *ldsym)
 279 {
 280   flagword flags = BSF_NO_FLAGS;
 281   struct bfd_section *section;
 282
 283   asym->the_bfd = abfd;
 284   asym->name = (ldsym->version
 285                 ? concat (ldsym->name, "@", ldsym->version, (const char *) NULL)
 286                 : ldsym->name);
 287   asym->value = 0;
 288   switch (ldsym->def)
 289     {
 290     case LDPK_WEAKDEF:
 291       flags = BSF_WEAK;
 292       /* FALLTHRU */
 293     case LDPK_DEF:
 294       flags |= BSF_GLOBAL;
 295       if (ldsym->comdat_key)
 296         {
 297           char *name = concat (".gnu.linkonce.t.", ldsym->comdat_key,
 298                                (const char *) NULL);
 299           section = bfd_get_section_by_name (abfd, name);
 300           if (section != NULL)
 301             free (name);
 302           else
 303             {
 304               flagword sflags;
 305
 306               sflags = (SEC_CODE | SEC_HAS_CONTENTS | SEC_READONLY
 307                         | SEC_ALLOC | SEC_LOAD | SEC_KEEP | SEC_EXCLUDE
 308                         | SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD);
 309               section = bfd_make_section_anyway_with_flags (abfd, name, sflags);
 310               if (section == NULL)
 311                 return LDPS_ERR;
 312             }
 313         }
 314       else
 315         section = bfd_get_section_by_name (abfd, ".text");
 316       break;
 317
 318     case LDPK_WEAKUNDEF:
 319       flags = BSF_WEAK;
 320       /* FALLTHRU */
 321     case LDPK_UNDEF:
 322       section = bfd_und_section_ptr;
 323       break;
 324
 325     case LDPK_COMMON:
 326       flags = BSF_GLOBAL;
 327       section = bfd_com_section_ptr;
 328       asym->value = ldsym->size;
 329       /* For ELF targets, set alignment of common symbol to 1.  */
 330       if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 331         {
 332           ((elf_symbol_type *) asym)->internal_elf_sym.st_shndx = SHN_COMMON;
 333           ((elf_symbol_type *) asym)->internal_elf_sym.st_value = 1;
 334         }
 335       break;
 336
 337     default:
 338       return LDPS_ERR;
 339     }
 340   asym->flags = flags;
 341   asym->section = section;
 342
 343   /* Visibility only applies on ELF targets.  */
 344   if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 345     {
 346       elf_symbol_type *elfsym = elf_symbol_from (abfd, asym);
 347       unsigned char visibility;
 348
 349       if (!elfsym)
 350         einfo (_("%P%F: %s: non-ELF symbol in ELF BFD!\n"), asym->name);
 351       switch (ldsym->visibility)
 352         {
 353         default:
 354           einfo (_("%P%F: unknown ELF symbol visibility: %d!\n"),
 355                  ldsym->visibility);
 356         case LDPV_DEFAULT:
 357           visibility = STV_DEFAULT;
 358           break;
 359         case LDPV_PROTECTED:
 360           visibility = STV_PROTECTED;
 361           break;
 362         case LDPV_INTERNAL:
 363           visibility = STV_INTERNAL;
 364           break;
 365         case LDPV_HIDDEN:
 366           visibility = STV_HIDDEN;
 367           break;
 368         }
 369       elfsym->internal_elf_sym.st_other
 370         = (visibility | (elfsym->internal_elf_sym.st_other
 371                          & ~ELF_ST_VISIBILITY (-1)));
 372     }
 373
 374   return LDPS_OK;
 375 }
 376
 377 /* Register a claim-file handler.  */
 378 static enum ld_plugin_status
 379 register_claim_file (ld_plugin_claim_file_handler handler)
 380 {
 381   ASSERT (called_plugin);
 382   called_plugin->claim_file_handler = handler;
 383   return LDPS_OK;
 384 }
 385
 386 /* Register an all-symbols-read handler.  */
 387 static enum ld_plugin_status
 388 register_all_symbols_read (ld_plugin_all_symbols_read_handler handler)
 389 {
 390   ASSERT (called_plugin);
 391   called_plugin->all_symbols_read_handler = handler;
 392   return LDPS_OK;
 393 }
 394
 395 /* Register a cleanup handler.  */
 396 static enum ld_plugin_status
 397 register_cleanup (ld_plugin_cleanup_handler handler)
 398 {
 399   ASSERT (called_plugin);
 400   called_plugin->cleanup_handler = handler;
 401   return LDPS_OK;
 402 }
 403
 404 /* Add symbols from a plugin-claimed input file.  */
 405 static enum ld_plugin_status
 406 add_symbols (void *handle, int nsyms, const struct ld_plugin_symbol *syms)
 407 {
 408   asymbol **symptrs;
 409   bfd *abfd = handle;
 410   int n;
 411
 412   ASSERT (called_plugin);
 413   symptrs = xmalloc (nsyms * sizeof *symptrs);
 414   for (n = 0; n < nsyms; n++)
 415     {
 416       enum ld_plugin_status rv;
 417       asymbol *bfdsym;
 418
 419       bfdsym = bfd_make_empty_symbol (abfd);
 420       symptrs[n] = bfdsym;
 421       rv = asymbol_from_plugin_symbol (abfd, bfdsym, syms + n);
 422       if (rv != LDPS_OK)
 423         return rv;
 424     }
 425   bfd_set_symtab (abfd, symptrs, nsyms);
 426   return LDPS_OK;
 427 }
 428
 429 /* Get the input file information with an open (possibly re-opened)
 430    file descriptor.  */
 431 static enum ld_plugin_status
 432 get_input_file (const void *handle, struct ld_plugin_input_file *file)
 433 {
 434   ASSERT (called_plugin);
 435   handle = handle;
 436   file = file;
 437   return LDPS_ERR;
 438 }
 439
 440 /* Release the input file.  */
 441 static enum ld_plugin_status
 442 release_input_file (const void *handle)
 443 {
 444   ASSERT (called_plugin);
 445   handle = handle;
 446   return LDPS_ERR;
 447 }
 448
 449 /* Return TRUE if a defined symbol might be reachable from outside the
 450    universe of claimed objects.  */
 451 static inline bfd_boolean
 452 is_visible_from_outside (struct ld_plugin_symbol *lsym,
 453                          struct bfd_link_hash_entry *blhe)
 454 {
 455   struct bfd_sym_chain *sym;
 456
 457   if (link_info.relocatable)
 458     return TRUE;
 459   if (link_info.export_dynamic || !link_info.executable)
 460     {
 461       /* Check if symbol is hidden by version script.  */
 462       if (bfd_hide_sym_by_version (link_info.version_info,
 463                                    blhe->root.string))
 464         return FALSE;
 465       /* Only ELF symbols really have visibility.  */
 466       if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
 467         {
 468           struct elf_link_hash_entry *el = (struct elf_link_hash_entry *)blhe;
 469           int vis = ELF_ST_VISIBILITY (el->other);
 470           return vis == STV_DEFAULT || vis == STV_PROTECTED;
 471         }
 472       /* On non-ELF targets, we can safely make inferences by considering
 473          what visibility the plugin would have liked to apply when it first
 474          sent us the symbol.  During ELF symbol processing, visibility only
 475          ever becomes more restrictive, not less, when symbols are merged,
 476          so this is a conservative estimate; it may give false positives,
 477          declaring something visible from outside when it in fact would
 478          not have been, but this will only lead to missed optimisation
 479          opportunities during LTRANS at worst; it will not give false
 480          negatives, which can lead to the disastrous conclusion that the
 481          related symbol is IRONLY.  (See GCC PR46319 for an example.)  */
 482       return (lsym->visibility == LDPV_DEFAULT
 483               || lsym->visibility == LDPV_PROTECTED);
 484     }
 485
 486   for (sym = &entry_symbol; sym != NULL; sym = sym->next)
 487     if (sym->name
 488         && strcmp (sym->name, blhe->root.string) == 0)
 489       return TRUE;
 490
 491   return FALSE;
 492 }
 493
 494 /* Get the symbol resolution info for a plugin-claimed input file.  */
 495 static enum ld_plugin_status
 496 get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms,
 497              int def_ironly_exp)
 498 {
 499   const bfd *abfd = handle;
 500   int n;
 501
 502   ASSERT (called_plugin);
 503   for (n = 0; n < nsyms; n++)
 504     {
 505       struct bfd_link_hash_entry *blhe;
 506       asection *owner_sec;
 507       int res;
 508
 509       if (syms[n].def != LDPK_UNDEF)
 510         blhe = bfd_link_hash_lookup (link_info.hash, syms[n].name,
 511                                      FALSE, FALSE, TRUE);
 512       else
 513         blhe = bfd_wrapped_link_hash_lookup (link_info.output_bfd, &link_info,
 514                                              syms[n].name, FALSE, FALSE, TRUE);
 515       if (!blhe)
 516         {
 517           res = LDPR_UNKNOWN;
 518           goto report_symbol;
 519         }
 520
 521       /* Determine resolution from blhe type and symbol's original type.  */
 522       if (blhe->type == bfd_link_hash_undefined
 523           || blhe->type == bfd_link_hash_undefweak)
 524         {
 525           res = LDPR_UNDEF;
 526           goto report_symbol;
 527         }
 528       if (blhe->type != bfd_link_hash_defined
 529           && blhe->type != bfd_link_hash_defweak
 530           && blhe->type != bfd_link_hash_common)
 531         {
 532           /* We should not have a new, indirect or warning symbol here.  */
 533           einfo ("%P%F: %s: plugin symbol table corrupt (sym type %d)\n",
 534                  called_plugin->name, blhe->type);
 535         }
 536
 537       /* Find out which section owns the symbol.  Since it's not undef,
 538          it must have an owner; if it's not a common symbol, both defs
 539          and weakdefs keep it in the same place. */
 540       owner_sec = (blhe->type == bfd_link_hash_common
 541                    ? blhe->u.c.p->section
 542                    : blhe->u.def.section);
 543
 544
 545       /* If it was originally undefined or common, then it has been
 546          resolved; determine how.  */
 547       if (syms[n].def == LDPK_UNDEF
 548           || syms[n].def == LDPK_WEAKUNDEF
 549           || syms[n].def == LDPK_COMMON)
 550         {
 551           if (owner_sec->owner == link_info.output_bfd)
 552             res = LDPR_RESOLVED_EXEC;
 553           else if (owner_sec->owner == abfd)
 554             res = LDPR_PREVAILING_DEF_IRONLY;
 555           else if (is_ir_dummy_bfd (owner_sec->owner))
 556             res = LDPR_RESOLVED_IR;
 557           else if (owner_sec->owner != NULL
 558                    && (owner_sec->owner->flags & DYNAMIC) != 0)
 559             res = LDPR_RESOLVED_DYN;
 560           else
 561             res = LDPR_RESOLVED_EXEC;
 562         }
 563
 564       /* Was originally def, or weakdef.  Does it prevail?  If the
 565          owner is the original dummy bfd that supplied it, then this
 566          is the definition that has prevailed.  */
 567       else if (owner_sec->owner == link_info.output_bfd)
 568         res = LDPR_PREEMPTED_REG;
 569       else if (owner_sec->owner == abfd)
 570         res = LDPR_PREVAILING_DEF_IRONLY;
 571
 572       /* Was originally def, weakdef, or common, but has been pre-empted.  */
 573       else if (is_ir_dummy_bfd (owner_sec->owner))
 574         res = LDPR_PREEMPTED_IR;
 575       else
 576         res = LDPR_PREEMPTED_REG;
 577
 578       if (res == LDPR_PREVAILING_DEF_IRONLY)
 579         {
 580           /* We need to know if the sym is referenced from non-IR files.  Or
 581              even potentially-referenced, perhaps in a future final link if
 582              this is a partial one, perhaps dynamically at load-time if the
 583              symbol is externally visible.  */
 584           if (blhe->non_ir_ref)
 585             res = LDPR_PREVAILING_DEF;
 586           else if (is_visible_from_outside (&syms[n], blhe))
 587             res = def_ironly_exp;
 588         }
 589
 590     report_symbol:
 591       syms[n].resolution = res;
 592       if (report_plugin_symbols)
 593         einfo (_("%P: %B: symbol `%s' "
 594                  "definition: %d, visibility: %d, resolution: %d\n"),
 595                abfd, syms[n].name,
 596                syms[n].def, syms[n].visibility, res);
 597     }
 598   return LDPS_OK;
 599 }
 600
 601 static enum ld_plugin_status
 602 get_symbols_v1 (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
 603 {
 604   return get_symbols (handle, nsyms, syms, LDPR_PREVAILING_DEF);
 605 }
 606
 607 static enum ld_plugin_status
 608 get_symbols_v2 (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
 609 {
 610   return get_symbols (handle, nsyms, syms, LDPR_PREVAILING_DEF_IRONLY_EXP);
 611 }
 612
 613 /* Add a new (real) input file generated by a plugin.  */
 614 static enum ld_plugin_status
 615 add_input_file (const char *pathname)
 616 {
 617   ASSERT (called_plugin);
 618   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_file_enum,
 619                             NULL))
 620     return LDPS_ERR;
 621   return LDPS_OK;
 622 }
 623
 624 /* Add a new (real) library required by a plugin.  */
 625 static enum ld_plugin_status
 626 add_input_library (const char *pathname)
 627 {
 628   ASSERT (called_plugin);
 629   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_l_enum,
 630                             NULL))
 631     return LDPS_ERR;
 632   return LDPS_OK;
 633 }
 634
 635 /* Set the extra library path to be used by libraries added via
 636    add_input_library.  */
 637 static enum ld_plugin_status
 638 set_extra_library_path (const char *path)
 639 {
 640   ASSERT (called_plugin);
 641   ldfile_add_library_path (xstrdup (path), FALSE);
 642   return LDPS_OK;
 643 }
 644
 645 /* Issue a diagnostic message from a plugin.  */
 646 static enum ld_plugin_status
 647 message (int level, const char *format, ...)
 648 {
 649   va_list args;
 650   va_start (args, format);
 651
 652   switch (level)
 653     {
 654     case LDPL_INFO:
 655       vfinfo (stdout, format, args, FALSE);
 656       putchar ('\n');
 657       break;
 658     case LDPL_WARNING:
 659       vfinfo (stdout, format, args, TRUE);
 660       putchar ('\n');
 661       break;
 662     case LDPL_FATAL:
 663     case LDPL_ERROR:
 664     default:
 665       {
 666         char *newfmt = ACONCAT ((level == LDPL_FATAL ? "%P%F: " : "%P%X: ",
 667                                  format, "\n", (const char *) NULL));
 668         fflush (stdout);
 669         vfinfo (stderr, newfmt, args, TRUE);
 670         fflush (stderr);
 671       }
 672       break;
 673     }
 674
 675   va_end (args);
 676   return LDPS_OK;
 677 }
 678
 679 /* Helper to size leading part of tv array and set it up. */
 680 static void
 681 set_tv_header (struct ld_plugin_tv *tv)
 682 {
 683   size_t i;
 684
 685   /* Version info.  */
 686   static const unsigned int major = (unsigned)(BFD_VERSION / 100000000UL);
 687   static const unsigned int minor = (unsigned)(BFD_VERSION / 1000000UL) % 100;
 688
 689   for (i = 0; i < tv_header_size; i++)
 690     {
 691       tv[i].tv_tag = tv_header_tags[i];
 692 #define TVU(x) tv[i].tv_u.tv_ ## x
 693       switch (tv[i].tv_tag)
 694         {
 695         case LDPT_MESSAGE:
 696           TVU(message) = message;
 697           break;
 698         case LDPT_API_VERSION:
 699           TVU(val) = LD_PLUGIN_API_VERSION;
 700           break;
 701         case LDPT_GNU_LD_VERSION:
 702           TVU(val) = major * 100 + minor;
 703           break;
 704         case LDPT_LINKER_OUTPUT:
 705           TVU(val) = (link_info.relocatable
 706                       ? LDPO_REL
 707                       : (link_info.executable
 708                          ? (link_info.pie ? LDPO_PIE : LDPO_EXEC)
 709                          : LDPO_DYN));
 710           break;
 711         case LDPT_OUTPUT_NAME:
 712           TVU(string) = output_filename;
 713           break;
 714         case LDPT_REGISTER_CLAIM_FILE_HOOK:
 715           TVU(register_claim_file) = register_claim_file;
 716           break;
 717         case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK:
 718           TVU(register_all_symbols_read) = register_all_symbols_read;
 719           break;
 720         case LDPT_REGISTER_CLEANUP_HOOK:
 721           TVU(register_cleanup) = register_cleanup;
 722           break;
 723         case LDPT_ADD_SYMBOLS:
 724           TVU(add_symbols) = add_symbols;
 725           break;
 726         case LDPT_GET_INPUT_FILE:
 727           TVU(get_input_file) = get_input_file;
 728           break;
 729         case LDPT_RELEASE_INPUT_FILE:
 730           TVU(release_input_file) = release_input_file;
 731           break;
 732         case LDPT_GET_SYMBOLS:
 733           TVU(get_symbols) = get_symbols_v1;
 734           break;
 735         case LDPT_GET_SYMBOLS_V2:
 736           TVU(get_symbols) = get_symbols_v2;
 737           break;
 738         case LDPT_ADD_INPUT_FILE:
 739           TVU(add_input_file) = add_input_file;
 740           break;
 741         case LDPT_ADD_INPUT_LIBRARY:
 742           TVU(add_input_library) = add_input_library;
 743           break;
 744         case LDPT_SET_EXTRA_LIBRARY_PATH:
 745           TVU(set_extra_library_path) = set_extra_library_path;
 746           break;
 747         default:
 748           /* Added a new entry to the array without adding
 749              a new case to set up its value is a bug.  */
 750           FAIL ();
 751         }
 752 #undef TVU
 753     }
 754 }
 755
 756 /* Append the per-plugin args list and trailing LDPT_NULL to tv.  */
 757 static void
 758 set_tv_plugin_args (plugin_t *plugin, struct ld_plugin_tv *tv)
 759 {
 760   plugin_arg_t *arg = plugin->args;
 761   while (arg)
 762     {
 763       tv->tv_tag = LDPT_OPTION;
 764       tv->tv_u.tv_string = arg->arg;
 765       arg = arg->next;
 766       tv++;
 767     }
 768   tv->tv_tag = LDPT_NULL;
 769   tv->tv_u.tv_val = 0;
 770 }
 771
 772 /* Return true if any plugins are active this run.  Only valid
 773    after options have been processed.  */
 774 bfd_boolean
 775 plugin_active_plugins_p (void)
 776 {
 777   return plugins_list != NULL;
 778 }
 779
 780 /* Load up and initialise all plugins after argument parsing.  */
 781 void
 782 plugin_load_plugins (void)
 783 {
 784   struct ld_plugin_tv *my_tv;
 785   unsigned int max_args = 0;
 786   plugin_t *curplug = plugins_list;
 787
 788   /* If there are no plugins, we need do nothing this run.  */
 789   if (!curplug)
 790     return;
 791
 792   /* First pass over plugins to find max # args needed so that we
 793      can size and allocate the tv array.  */
 794   while (curplug)
 795     {
 796       if (curplug->n_args > max_args)
 797         max_args = curplug->n_args;
 798       curplug = curplug->next;
 799     }
 800
 801   /* Allocate tv array and initialise constant part.  */
 802   my_tv = xmalloc ((max_args + 1 + tv_header_size) * sizeof *my_tv);
 803   set_tv_header (my_tv);
 804
 805   /* Pass over plugins again, activating them.  */
 806   curplug = plugins_list;
 807   while (curplug)
 808     {
 809       enum ld_plugin_status rv;
 810       ld_plugin_onload onloadfn;
 811
 812       onloadfn = (ld_plugin_onload) dlsym (curplug->dlhandle, "onload");
 813       if (!onloadfn)
 814         onloadfn = (ld_plugin_onload) dlsym (curplug->dlhandle, "_onload");
 815       if (!onloadfn)
 816         einfo (_("%P%F: %s: error loading plugin: %s\n"),
 817                curplug->name, dlerror ());
 818       set_tv_plugin_args (curplug, &my_tv[tv_header_size]);
 819       called_plugin = curplug;
 820       rv = (*onloadfn) (my_tv);
 821       called_plugin = NULL;
 822       if (rv != LDPS_OK)
 823         einfo (_("%P%F: %s: plugin error: %d\n"), curplug->name, rv);
 824       curplug = curplug->next;
 825     }
 826
 827   /* Since plugin(s) inited ok, assume they're going to want symbol
 828      resolutions, which needs us to track which symbols are referenced
 829      by non-IR files using the linker's notice callback.  */
 830   orig_notice_all = link_info.notice_all;
 831   orig_callbacks = link_info.callbacks;
 832   plugin_callbacks = *orig_callbacks;
 833   plugin_callbacks.notice = &plugin_notice;
 834   link_info.notice_all = TRUE;
 835   link_info.callbacks = &plugin_callbacks;
 836 }
 837
 838 /* Call 'claim file' hook for all plugins.  */
 839 static int
 840 plugin_call_claim_file (const struct ld_plugin_input_file *file, int *claimed)
 841 {
 842   plugin_t *curplug = plugins_list;
 843   *claimed = FALSE;
 844   if (no_more_claiming)
 845     return 0;
 846   while (curplug && !*claimed)
 847     {
 848       if (curplug->claim_file_handler)
 849         {
 850           enum ld_plugin_status rv;
 851           called_plugin = curplug;
 852           rv = (*curplug->claim_file_handler) (file, claimed);
 853           called_plugin = NULL;
 854           if (rv != LDPS_OK)
 855             set_plugin_error (curplug->name);
 856         }
 857       curplug = curplug->next;
 858     }
 859   return plugin_error_p () ? -1 : 0;
 860 }
 861
 862 void
 863 plugin_maybe_claim (struct ld_plugin_input_file *file,
 864                     lang_input_statement_type *entry)
 865 {
 866   int claimed = 0;
 867
 868   /* We create a dummy BFD, initially empty, to house whatever symbols
 869      the plugin may want to add.  */
 870   file->handle = plugin_get_ir_dummy_bfd (entry->the_bfd->filename,
 871                                           entry->the_bfd);
 872   if (plugin_call_claim_file (file, &claimed))
 873     einfo (_("%P%F: %s: plugin reported error claiming file\n"),
 874            plugin_error_plugin ());
 875   /* fd belongs to us, not the plugin; but we don't need it.  */
 876   close (file->fd);
 877   if (claimed)
 878     {
 879       /* Discard the real file's BFD and substitute the dummy one.  */
 880
 881       /* BFD archive handling caches elements so we can't call
 882          bfd_close for archives.  */
 883       if (entry->the_bfd->my_archive == NULL)
 884         bfd_close (entry->the_bfd);
 885       entry->the_bfd = file->handle;
 886       entry->flags.claimed = TRUE;
 887       bfd_make_readable (entry->the_bfd);
 888     }
 889   else
 890     {
 891       /* If plugin didn't claim the file, we don't need the dummy bfd.
 892          Can't avoid speculatively creating it, alas.  */
 893       bfd_close_all_done (file->handle);
 894       entry->flags.claimed = FALSE;
 895     }
 896 }
 897
 898 /* Call 'all symbols read' hook for all plugins.  */
 899 int
 900 plugin_call_all_symbols_read (void)
 901 {
 902   plugin_t *curplug = plugins_list;
 903
 904   /* Disable any further file-claiming.  */
 905   no_more_claiming = TRUE;
 906
 907   while (curplug)
 908     {
 909       if (curplug->all_symbols_read_handler)
 910         {
 911           enum ld_plugin_status rv;
 912           called_plugin = curplug;
 913           rv = (*curplug->all_symbols_read_handler) ();
 914           called_plugin = NULL;
 915           if (rv != LDPS_OK)
 916             set_plugin_error (curplug->name);
 917         }
 918       curplug = curplug->next;
 919     }
 920   return plugin_error_p () ? -1 : 0;
 921 }
 922
 923 /* Call 'cleanup' hook for all plugins at exit.  */
 924 void
 925 plugin_call_cleanup (void)
 926 {
 927   plugin_t *curplug = plugins_list;
 928   while (curplug)
 929     {
 930       if (curplug->cleanup_handler && !curplug->cleanup_done)
 931         {
 932           enum ld_plugin_status rv;
 933           curplug->cleanup_done = TRUE;
 934           called_plugin = curplug;
 935           rv = (*curplug->cleanup_handler) ();
 936           called_plugin = NULL;
 937           if (rv != LDPS_OK)
 938             info_msg (_("%P: %s: error in plugin cleanup: %d (ignored)\n"),
 939                       curplug->name, rv);
 940           dlclose (curplug->dlhandle);
 941         }
 942       curplug = curplug->next;
 943     }
 944 }
 945
 946 /* To determine which symbols should be resolved LDPR_PREVAILING_DEF
 947    and which LDPR_PREVAILING_DEF_IRONLY, we notice all the symbols as
 948    the linker adds them to the linker hash table.  Mark those
 949    referenced from a non-IR file with non_ir_ref.  We have to
 950    notice_all symbols, because we won't necessarily know until later
 951    which ones will be contributed by IR files.  */
 952 static bfd_boolean
 953 plugin_notice (struct bfd_link_info *info,
 954                struct bfd_link_hash_entry *h,
 955                bfd *abfd,
 956                asection *section,
 957                bfd_vma value,
 958                flagword flags,
 959                const char *string)
 960 {
 961   if (h != NULL)
 962     {
 963       bfd *sym_bfd;
 964
 965       /* Nothing to do here if this def/ref is from an IR dummy BFD.  */
 966       if (is_ir_dummy_bfd (abfd))
 967         ;
 968
 969       /* Making an indirect symbol counts as a reference unless this
 970          is a brand new symbol.  */
 971       else if (bfd_is_ind_section (section)
 972                || (flags & BSF_INDIRECT) != 0)
 973         {
 974           if (h->type != bfd_link_hash_new)
 975             {
 976               struct bfd_link_hash_entry *inh;
 977
 978               h->non_ir_ref = TRUE;
 979               inh = bfd_wrapped_link_hash_lookup (abfd, info, string, FALSE,
 980                                                   FALSE, FALSE);
 981               if (inh != NULL)
 982                 inh->non_ir_ref = TRUE;
 983             }
 984         }
 985
 986       /* Nothing to do here for warning symbols.  */
 987       else if ((flags & BSF_WARNING) != 0)
 988         ;
 989
 990       /* Nothing to do here for constructor symbols.  */
 991       else if ((flags & BSF_CONSTRUCTOR) != 0)
 992         ;
 993
 994       /* If this is a ref, set non_ir_ref.  */
 995       else if (bfd_is_und_section (section))
 996         h->non_ir_ref = TRUE;
 997
 998       /* Otherwise, it must be a new def.  Ensure any symbol defined
 999          in an IR dummy BFD takes on a new value from a real BFD.
1000          Weak symbols are not normally overridden by a new weak
1001          definition, and strong symbols will normally cause multiple
1002          definition errors.  Avoid this by making the symbol appear
1003          to be undefined.  */
1004       else if (((h->type == bfd_link_hash_defweak
1005                  || h->type == bfd_link_hash_defined)
1006                 && is_ir_dummy_bfd (sym_bfd = h->u.def.section->owner))
1007                || (h->type == bfd_link_hash_common
1008                    && is_ir_dummy_bfd (sym_bfd = h->u.c.p->section->owner)))
1009         {
1010           h->type = bfd_link_hash_undefweak;
1011           h->u.undef.abfd = sym_bfd;
1012         }
1013     }
1014
1015   /* Continue with cref/nocrossref/trace-sym processing.  */
1016   if (h == NULL
1017       || orig_notice_all
1018       || (info->notice_hash != NULL
1019           && bfd_hash_lookup (info->notice_hash, h->root.string,
1020                               FALSE, FALSE) != NULL))
1021     return (*orig_callbacks->notice) (info, h,
1022                                       abfd, section, value, flags, string);
1023   return TRUE;
1024 }
1025
1026 /* Return true if bfd is a dynamic library that should be reloaded.  */
1027
1028 bfd_boolean
1029 plugin_should_reload (bfd *abfd)
1030 {
1031   return ((abfd->flags & DYNAMIC) != 0
1032           && bfd_get_flavour (abfd) == bfd_target_elf_flavour
1033           && bfd_get_format (abfd) == bfd_object
1034           && (elf_dyn_lib_class (abfd) & DYN_AS_NEEDED) != 0);
1035 }