gold/plugin.h

   1 // plugin.h -- plugin manager for gold      -*- C++ -*-
   2
   3 // Copyright (C) 2008-2017 Free Software Foundation, Inc.
   4 // Written by Cary Coutant <ccoutant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #ifndef GOLD_PLUGIN_H
  24 #define GOLD_PLUGIN_H
  25
  26 #include <list>
  27 #include <string>
  28
  29 #include "object.h"
  30 #include "plugin-api.h"
  31 #include "workqueue.h"
  32
  33 namespace gold
  34 {
  35
  36 class General_options;
  37 class Input_file;
  38 class Input_objects;
  39 class Archive;
  40 class Input_group;
  41 class Symbol;
  42 class Symbol_table;
  43 class Layout;
  44 class Dirsearch;
  45 class Mapfile;
  46 class Task;
  47 class Task_token;
  48 class Pluginobj;
  49 class Plugin_rescan;
  50
  51 // This class represents a single plugin library.
  52
  53 class Plugin
  54 {
  55  public:
  56   Plugin(const char* filename)
  57     : handle_(NULL),
  58       filename_(filename),
  59       args_(),
  60       claim_file_handler_(NULL),
  61       all_symbols_read_handler_(NULL),
  62       cleanup_handler_(NULL),
  63       cleanup_done_(false)
  64   { }
  65
  66   ~Plugin()
  67   { }
  68
  69   // Load the library and call its entry point.
  70   void
  71   load();
  72
  73   // Call the claim-file handler.
  74   bool
  75   claim_file(struct ld_plugin_input_file* plugin_input_file);
  76
  77   // Call the all-symbols-read handler.
  78   void
  79   all_symbols_read();
  80
  81   // Call the cleanup handler.
  82   void
  83   cleanup();
  84
  85   // Register a claim-file handler.
  86   void
  87   set_claim_file_handler(ld_plugin_claim_file_handler handler)
  88   { this->claim_file_handler_ = handler; }
  89
  90   // Register an all-symbols-read handler.
  91   void
  92   set_all_symbols_read_handler(ld_plugin_all_symbols_read_handler handler)
  93   { this->all_symbols_read_handler_ = handler; }
  94
  95   // Register a claim-file handler.
  96   void
  97   set_cleanup_handler(ld_plugin_cleanup_handler handler)
  98   { this->cleanup_handler_ = handler; }
  99
 100   // Add an argument
 101   void
 102   add_option(const char* arg)
 103   {
 104     this->args_.push_back(arg);
 105   }
 106
 107  private:
 108   Plugin(const Plugin&);
 109   Plugin& operator=(const Plugin&);
 110
 111   // The shared library handle returned by dlopen.
 112   void* handle_;
 113   // The argument string given to --plugin.
 114   std::string filename_;
 115   // The list of argument string given to --plugin-opt.
 116   std::vector<std::string> args_;
 117   // The plugin's event handlers.
 118   ld_plugin_claim_file_handler claim_file_handler_;
 119   ld_plugin_all_symbols_read_handler all_symbols_read_handler_;
 120   ld_plugin_cleanup_handler cleanup_handler_;
 121   // TRUE if the cleanup handlers have been called.
 122   bool cleanup_done_;
 123 };
 124
 125 // A manager class for plugins.
 126
 127 class Plugin_manager
 128 {
 129  public:
 130   Plugin_manager(const General_options& options)
 131     : plugins_(), objects_(), deferred_layout_objects_(), input_file_(NULL),
 132       plugin_input_file_(), rescannable_(), undefined_symbols_(),
 133       any_claimed_(false), in_replacement_phase_(false), any_added_(false),
 134       in_claim_file_handler_(false),
 135       options_(options), workqueue_(NULL), task_(NULL), input_objects_(NULL),
 136       symtab_(NULL), layout_(NULL), dirpath_(NULL), mapfile_(NULL),
 137       this_blocker_(NULL), extra_search_path_(), lock_(NULL),
 138       initialize_lock_(&lock_)
 139   { this->current_ = plugins_.end(); }
 140
 141   ~Plugin_manager();
 142
 143   // Add a plugin library.
 144   void
 145   add_plugin(const char* filename)
 146   { this->plugins_.push_back(new Plugin(filename)); }
 147
 148   // Add an argument to the current plugin.
 149   void
 150   add_plugin_option(const char* opt)
 151   {
 152     Plugin* last = this->plugins_.back();
 153     last->add_option(opt);
 154   }
 155
 156   // Load all plugin libraries.
 157   void
 158   load_plugins(Layout* layout);
 159
 160   // Call the plugin claim-file handlers in turn to see if any claim the file.
 161   Pluginobj*
 162   claim_file(Input_file* input_file, off_t offset, off_t filesize,
 163              Object* elf_object);
 164
 165   // Get the object associated with the handle and check if it is an elf object.
 166   // If it is not a Pluginobj, it is an elf object.
 167   Object*
 168   get_elf_object(const void* handle);
 169
 170   // True if the claim_file handler of the plugins is being called.
 171   bool
 172   in_claim_file_handler()
 173   { return in_claim_file_handler_; }
 174
 175   // Let the plugin manager save an archive for later rescanning.
 176   // This takes ownership of the Archive pointer.
 177   void
 178   save_archive(Archive*);
 179
 180   // Let the plugin manager save an input group for later rescanning.
 181   // This takes ownership of the Input_group pointer.
 182   void
 183   save_input_group(Input_group*);
 184
 185   // Call the all-symbols-read handlers.
 186   void
 187   all_symbols_read(Workqueue* workqueue, Task* task,
 188                    Input_objects* input_objects, Symbol_table* symtab,
 189                    Dirsearch* dirpath, Mapfile* mapfile,
 190                    Task_token** last_blocker);
 191
 192   // Tell the plugin manager that we've a new undefined symbol which
 193   // may require rescanning.
 194   void
 195   new_undefined_symbol(Symbol*);
 196
 197   // Run deferred layout.
 198   void
 199   layout_deferred_objects();
 200
 201   // Call the cleanup handlers.
 202   void
 203   cleanup();
 204
 205   // Register a claim-file handler.
 206   void
 207   set_claim_file_handler(ld_plugin_claim_file_handler handler)
 208   {
 209     gold_assert(this->current_ != plugins_.end());
 210     (*this->current_)->set_claim_file_handler(handler);
 211   }
 212
 213   // Register an all-symbols-read handler.
 214   void
 215   set_all_symbols_read_handler(ld_plugin_all_symbols_read_handler handler)
 216   {
 217     gold_assert(this->current_ != plugins_.end());
 218     (*this->current_)->set_all_symbols_read_handler(handler);
 219   }
 220
 221   // Register a claim-file handler.
 222   void
 223   set_cleanup_handler(ld_plugin_cleanup_handler handler)
 224   {
 225     gold_assert(this->current_ != plugins_.end());
 226     (*this->current_)->set_cleanup_handler(handler);
 227   }
 228
 229   // Make a new Pluginobj object.  This is called when the plugin calls
 230   // the add_symbols API.
 231   Pluginobj*
 232   make_plugin_object(unsigned int handle);
 233
 234   // Return the object associated with the given HANDLE.
 235   Object*
 236   object(unsigned int handle) const
 237   {
 238     if (handle >= this->objects_.size())
 239       return NULL;
 240     return this->objects_[handle];
 241   }
 242
 243   // Return TRUE if any input files have been claimed by a plugin
 244   // and we are still in the initial input phase.
 245   bool
 246   should_defer_layout() const
 247   { return this->any_claimed_ && !this->in_replacement_phase_; }
 248
 249   // Add a regular object to the deferred layout list.  These are
 250   // objects whose layout has been deferred until after the
 251   // replacement files have arrived.
 252   void
 253   add_deferred_layout_object(Relobj* obj)
 254   { this->deferred_layout_objects_.push_back(obj); }
 255
 256   // Get input file information with an open (possibly re-opened)
 257   // file descriptor.
 258   ld_plugin_status
 259   get_input_file(unsigned int handle, struct ld_plugin_input_file* file);
 260
 261   ld_plugin_status
 262   get_view(unsigned int handle, const void **viewp);
 263
 264   // Release an input file.
 265   ld_plugin_status
 266   release_input_file(unsigned int handle);
 267
 268   // Add a new input file.
 269   ld_plugin_status
 270   add_input_file(const char* pathname, bool is_lib);
 271
 272   // Set the extra library path.
 273   ld_plugin_status
 274   set_extra_library_path(const char* path);
 275
 276   // Return TRUE if we are in the replacement phase.
 277   bool
 278   in_replacement_phase() const
 279   { return this->in_replacement_phase_; }
 280
 281   Input_objects*
 282   input_objects() const
 283   { return this->input_objects_; }
 284
 285   Symbol_table*
 286   symtab()
 287   { return this->symtab_; }
 288
 289   Layout*
 290   layout()
 291   { return this->layout_; }
 292
 293  private:
 294   Plugin_manager(const Plugin_manager&);
 295   Plugin_manager& operator=(const Plugin_manager&);
 296
 297   // Plugin_rescan is a Task which calls the private rescan method.
 298   friend class Plugin_rescan;
 299
 300   // An archive or input group which may have to be rescanned if a
 301   // plugin adds a new file.
 302   struct Rescannable
 303   {
 304     bool is_archive;
 305     union
 306     {
 307       Archive* archive;
 308       Input_group* input_group;
 309     } u;
 310
 311     Rescannable(Archive* archive)
 312       : is_archive(true)
 313     { this->u.archive = archive; }
 314
 315     Rescannable(Input_group* input_group)
 316       : is_archive(false)
 317     { this->u.input_group = input_group; }
 318   };
 319
 320   typedef std::list<Plugin*> Plugin_list;
 321   typedef std::vector<Object*> Object_list;
 322   typedef std::vector<Relobj*> Deferred_layout_list;
 323   typedef std::vector<Rescannable> Rescannable_list;
 324   typedef std::vector<Symbol*> Undefined_symbol_list;
 325
 326   // Rescan archives for undefined symbols.
 327   void
 328   rescan(Task*);
 329
 330   // See whether the rescannable at index I defines SYM.
 331   bool
 332   rescannable_defines(size_t i, Symbol* sym);
 333
 334   // The list of plugin libraries.
 335   Plugin_list plugins_;
 336   // A pointer to the current plugin.  Used while loading plugins.
 337   Plugin_list::iterator current_;
 338
 339   // The list of plugin objects.  The index of an item in this list
 340   // serves as the "handle" that we pass to the plugins.
 341   Object_list objects_;
 342
 343   // The list of regular objects whose layout has been deferred.
 344   Deferred_layout_list deferred_layout_objects_;
 345
 346   // The file currently up for claim by the plugins.
 347   Input_file* input_file_;
 348   struct ld_plugin_input_file plugin_input_file_;
 349
 350   // A list of archives and input groups being saved for possible
 351   // later rescanning.
 352   Rescannable_list rescannable_;
 353
 354   // A list of undefined symbols found in added files.
 355   Undefined_symbol_list undefined_symbols_;
 356
 357   // Whether any input files have been claimed by a plugin.
 358   bool any_claimed_;
 359
 360   // Set to true after the all symbols read event; indicates that we
 361   // are processing replacement files whose symbols should replace the
 362   // placeholder symbols from the Pluginobj objects.
 363   bool in_replacement_phase_;
 364
 365   // Whether any input files or libraries were added by a plugin.
 366   bool any_added_;
 367
 368   // Set to true when the claim_file handler of a plugin is called.
 369   bool in_claim_file_handler_;
 370
 371   const General_options& options_;
 372   Workqueue* workqueue_;
 373   Task* task_;
 374   Input_objects* input_objects_;
 375   Symbol_table* symtab_;
 376   Layout* layout_;
 377   Dirsearch* dirpath_;
 378   Mapfile* mapfile_;
 379   Task_token* this_blocker_;
 380
 381   // An extra directory to search for the libraries passed by
 382   // add_input_library.
 383   std::string extra_search_path_;
 384   Lock* lock_;
 385   Initialize_lock initialize_lock_;
 386 };
 387
 388
 389 // An object file claimed by a plugin.  This is an abstract base class.
 390 // The implementation is the template class Sized_pluginobj.
 391
 392 class Pluginobj : public Object
 393 {
 394  public:
 395
 396   typedef std::vector<Symbol*> Symbols;
 397
 398   Pluginobj(const std::string& name, Input_file* input_file, off_t offset,
 399             off_t filesize);
 400
 401   // Fill in the symbol resolution status for the given plugin symbols.
 402   ld_plugin_status
 403   get_symbol_resolution_info(Symbol_table* symtab,
 404                              int nsyms,
 405                              ld_plugin_symbol* syms,
 406                              int version) const;
 407
 408   // Store the incoming symbols from the plugin for later processing.
 409   void
 410   store_incoming_symbols(int nsyms, const struct ld_plugin_symbol* syms)
 411   {
 412     this->nsyms_ = nsyms;
 413     this->syms_ = syms;
 414   }
 415
 416   // Return TRUE if the comdat group with key COMDAT_KEY from this object
 417   // should be kept.
 418   bool
 419   include_comdat_group(std::string comdat_key, Layout* layout);
 420
 421   // Return the filename.
 422   const std::string&
 423   filename() const
 424   { return this->input_file()->filename(); }
 425
 426   // Return the file descriptor.
 427   int
 428   descriptor()
 429   { return this->input_file()->file().descriptor(); }
 430
 431   // Return the size of the file or archive member.
 432   off_t
 433   filesize()
 434   { return this->filesize_; }
 435
 436   // Return the word size of the object file.
 437   int
 438   elfsize() const
 439   { gold_unreachable(); }
 440
 441   // Return TRUE if this is a big-endian object file.
 442   bool
 443   is_big_endian() const
 444   { gold_unreachable(); }
 445
 446  protected:
 447   // Return TRUE if this is an object claimed by a plugin.
 448   virtual Pluginobj*
 449   do_pluginobj()
 450   { return this; }
 451
 452   // The number of symbols provided by the plugin.
 453   int nsyms_;
 454
 455   // The symbols provided by the plugin.
 456   const struct ld_plugin_symbol* syms_;
 457
 458   // The entries in the symbol table for the external symbols.
 459   Symbols symbols_;
 460
 461  private:
 462   // Size of the file (or archive member).
 463   off_t filesize_;
 464   // Map a comdat key symbol to a boolean indicating whether the comdat
 465   // group in this object with that key should be kept.
 466   typedef Unordered_map<std::string, bool> Comdat_map;
 467   Comdat_map comdat_map_;
 468 };
 469
 470 // A plugin object, size-specific version.
 471
 472 template<int size, bool big_endian>
 473 class Sized_pluginobj : public Pluginobj
 474 {
 475  public:
 476   Sized_pluginobj(const std::string& name, Input_file* input_file,
 477                   off_t offset, off_t filesize);
 478
 479   // Read the symbols.
 480   void
 481   do_read_symbols(Read_symbols_data*);
 482
 483   // Lay out the input sections.
 484   void
 485   do_layout(Symbol_table*, Layout*, Read_symbols_data*);
 486
 487   // Add the symbols to the symbol table.
 488   void
 489   do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*);
 490
 491   Archive::Should_include
 492   do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*,
 493                            std::string* why);
 494
 495   // Iterate over global symbols, calling a visitor class V for each.
 496   void
 497   do_for_all_global_symbols(Read_symbols_data* sd,
 498                             Library_base::Symbol_visitor_base* v);
 499
 500   // Iterate over local symbols, calling a visitor class V for each GOT offset
 501   // associated with a local symbol.
 502   void
 503   do_for_all_local_got_entries(Got_offset_list::Visitor* v) const;
 504
 505   // Get the size of a section.
 506   uint64_t
 507   do_section_size(unsigned int shndx);
 508
 509   // Get the name of a section.
 510   std::string
 511   do_section_name(unsigned int shndx) const;
 512
 513   // Return a view of the contents of a section.
 514   const unsigned char*
 515   do_section_contents(unsigned int shndx, section_size_type* plen,
 516                       bool cache);
 517
 518   // Return section flags.
 519   uint64_t
 520   do_section_flags(unsigned int shndx);
 521
 522   // Return section entsize.
 523   uint64_t
 524   do_section_entsize(unsigned int shndx);
 525
 526   // Return section address.
 527   uint64_t
 528   do_section_address(unsigned int shndx);
 529
 530   // Return section type.
 531   unsigned int
 532   do_section_type(unsigned int shndx);
 533
 534   // Return the section link field.
 535   unsigned int
 536   do_section_link(unsigned int shndx);
 537
 538   // Return the section link field.
 539   unsigned int
 540   do_section_info(unsigned int shndx);
 541
 542   // Return the section alignment.
 543   uint64_t
 544   do_section_addralign(unsigned int shndx);
 545
 546   // Return the Xindex structure to use.
 547   Xindex*
 548   do_initialize_xindex();
 549
 550   // Get symbol counts.
 551   void
 552   do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;
 553
 554   // Get global symbols.
 555   const Symbols*
 556   do_get_global_symbols() const;
 557
 558   // Add placeholder symbols from a claimed file.
 559   ld_plugin_status
 560   add_symbols_from_plugin(int nsyms, const ld_plugin_symbol* syms);
 561
 562  protected:
 563
 564  private:
 565 };
 566
 567 // This Task handles handles the "all symbols read" event hook.
 568 // The plugin may add additional input files at this time, which must
 569 // be queued for reading.
 570
 571 class Plugin_hook : public Task
 572 {
 573  public:
 574   Plugin_hook(const General_options& options, Input_objects* input_objects,
 575               Symbol_table* symtab, Layout* /*layout*/, Dirsearch* dirpath,
 576               Mapfile* mapfile, Task_token* this_blocker,
 577               Task_token* next_blocker)
 578     : options_(options), input_objects_(input_objects), symtab_(symtab),
 579       dirpath_(dirpath), mapfile_(mapfile),
 580       this_blocker_(this_blocker), next_blocker_(next_blocker)
 581   { }
 582
 583   ~Plugin_hook();
 584
 585   // The standard Task methods.
 586
 587   Task_token*
 588   is_runnable();
 589
 590   void
 591   locks(Task_locker*);
 592
 593   void
 594   run(Workqueue*);
 595
 596   std::string
 597   get_name() const
 598   { return "Plugin_hook"; }
 599
 600  private:
 601   const General_options& options_;
 602   Input_objects* input_objects_;
 603   Symbol_table* symtab_;
 604   Dirsearch* dirpath_;
 605   Mapfile* mapfile_;
 606   Task_token* this_blocker_;
 607   Task_token* next_blocker_;
 608 };
 609
 610 } // End namespace gold.
 611
 612 #endif // !defined(GOLD_PLUGIN_H)