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       new_input_handler_(NULL),
  64       cleanup_done_(false)
  65   { }
  66
  67   ~Plugin()
  68   { }
  69
  70   // Load the library and call its entry point.
  71   void
  72   load();
  73
  74   // Call the claim-file handler.
  75   bool
  76   claim_file(struct ld_plugin_input_file* plugin_input_file);
  77
  78   // Call the all-symbols-read handler.
  79   void
  80   all_symbols_read();
  81
  82   // Call the new_input handler.
  83   void
  84   new_input(struct ld_plugin_input_file* plugin_input_file);
  85
  86   // Call the cleanup handler.
  87   void
  88   cleanup();
  89
  90   // Register a claim-file handler.
  91   void
  92   set_claim_file_handler(ld_plugin_claim_file_handler handler)
  93   { this->claim_file_handler_ = handler; }
  94
  95   // Register an all-symbols-read handler.
  96   void
  97   set_all_symbols_read_handler(ld_plugin_all_symbols_read_handler handler)
  98   { this->all_symbols_read_handler_ = handler; }
  99
 100   // Register a claim-file handler.
 101   void
 102   set_cleanup_handler(ld_plugin_cleanup_handler handler)
 103   { this->cleanup_handler_ = handler; }
 104
 105   // Register a new_input handler.
 106   void
 107   set_new_input_handler(ld_plugin_new_input_handler handler)
 108   { this->new_input_handler_ = handler; }
 109
 110   // Add an argument
 111   void
 112   add_option(const char* arg)
 113   {
 114     this->args_.push_back(arg);
 115   }
 116
 117  private:
 118   Plugin(const Plugin&);
 119   Plugin& operator=(const Plugin&);
 120
 121   // The shared library handle returned by dlopen.
 122   void* handle_;
 123   // The argument string given to --plugin.
 124   std::string filename_;
 125   // The list of argument string given to --plugin-opt.
 126   std::vector<std::string> args_;
 127   // The plugin's event handlers.
 128   ld_plugin_claim_file_handler claim_file_handler_;
 129   ld_plugin_all_symbols_read_handler all_symbols_read_handler_;
 130   ld_plugin_cleanup_handler cleanup_handler_;
 131   ld_plugin_new_input_handler new_input_handler_;
 132   // TRUE if the cleanup handlers have been called.
 133   bool cleanup_done_;
 134 };
 135
 136 // A manager class for plugins.
 137
 138 class Plugin_manager
 139 {
 140  public:
 141   Plugin_manager(const General_options& options)
 142     : plugins_(), objects_(), deferred_layout_objects_(), input_file_(NULL),
 143       plugin_input_file_(), rescannable_(), undefined_symbols_(),
 144       any_claimed_(false), in_replacement_phase_(false), any_added_(false),
 145       in_claim_file_handler_(false),
 146       options_(options), workqueue_(NULL), task_(NULL), input_objects_(NULL),
 147       symtab_(NULL), layout_(NULL), dirpath_(NULL), mapfile_(NULL),
 148       this_blocker_(NULL), extra_search_path_(), lock_(NULL),
 149       initialize_lock_(&lock_)
 150   { this->current_ = plugins_.end(); }
 151
 152   ~Plugin_manager();
 153
 154   // Add a plugin library.
 155   void
 156   add_plugin(const char* filename)
 157   { this->plugins_.push_back(new Plugin(filename)); }
 158
 159   // Add an argument to the current plugin.
 160   void
 161   add_plugin_option(const char* opt)
 162   {
 163     Plugin* last = this->plugins_.back();
 164     last->add_option(opt);
 165   }
 166
 167   // Load all plugin libraries.
 168   void
 169   load_plugins(Layout* layout);
 170
 171   // Call the plugin claim-file handlers in turn to see if any claim the file.
 172   Pluginobj*
 173   claim_file(Input_file* input_file, off_t offset, off_t filesize,
 174              Object* elf_object);
 175
 176   // Get the object associated with the handle and check if it is an elf object.
 177   // If it is not a Pluginobj, it is an elf object.
 178   Object*
 179   get_elf_object(const void* handle);
 180
 181   // True if the claim_file handler of the plugins is being called.
 182   bool
 183   in_claim_file_handler()
 184   { return in_claim_file_handler_; }
 185
 186   // Let the plugin manager save an archive for later rescanning.
 187   // This takes ownership of the Archive pointer.
 188   void
 189   save_archive(Archive*);
 190
 191   // Let the plugin manager save an input group for later rescanning.
 192   // This takes ownership of the Input_group pointer.
 193   void
 194   save_input_group(Input_group*);
 195
 196   // Call the all-symbols-read handlers.
 197   void
 198   all_symbols_read(Workqueue* workqueue, Task* task,
 199                    Input_objects* input_objects, Symbol_table* symtab,
 200                    Dirsearch* dirpath, Mapfile* mapfile,
 201                    Task_token** last_blocker);
 202
 203   // Tell the plugin manager that we've a new undefined symbol which
 204   // may require rescanning.
 205   void
 206   new_undefined_symbol(Symbol*);
 207
 208   // Run deferred layout.
 209   void
 210   layout_deferred_objects();
 211
 212   // Call the cleanup handlers.
 213   void
 214   cleanup();
 215
 216   // Register a claim-file handler.
 217   void
 218   set_claim_file_handler(ld_plugin_claim_file_handler handler)
 219   {
 220     gold_assert(this->current_ != plugins_.end());
 221     (*this->current_)->set_claim_file_handler(handler);
 222   }
 223
 224   // Register an all-symbols-read handler.
 225   void
 226   set_all_symbols_read_handler(ld_plugin_all_symbols_read_handler handler)
 227   {
 228     gold_assert(this->current_ != plugins_.end());
 229     (*this->current_)->set_all_symbols_read_handler(handler);
 230   }
 231
 232   // Register a new_input handler.
 233   void
 234   set_new_input_handler(ld_plugin_new_input_handler handler)
 235   {
 236     gold_assert(this->current_ != plugins_.end());
 237     (*this->current_)->set_new_input_handler(handler);
 238   }
 239
 240   // Register a claim-file handler.
 241   void
 242   set_cleanup_handler(ld_plugin_cleanup_handler handler)
 243   {
 244     gold_assert(this->current_ != plugins_.end());
 245     (*this->current_)->set_cleanup_handler(handler);
 246   }
 247
 248   // Make a new Pluginobj object.  This is called when the plugin calls
 249   // the add_symbols API.
 250   Pluginobj*
 251   make_plugin_object(unsigned int handle);
 252
 253   // Return the object associated with the given HANDLE.
 254   Object*
 255   object(unsigned int handle) const
 256   {
 257     if (handle >= this->objects_.size())
 258       return NULL;
 259     return this->objects_[handle];
 260   }
 261
 262   // Return TRUE if any input files have been claimed by a plugin
 263   // and we are still in the initial input phase.
 264   bool
 265   should_defer_layout() const
 266   { return this->any_claimed_ && !this->in_replacement_phase_; }
 267
 268   // Add a regular object to the deferred layout list.  These are
 269   // objects whose layout has been deferred until after the
 270   // replacement files have arrived.
 271   void
 272   add_deferred_layout_object(Relobj* obj)
 273   { this->deferred_layout_objects_.push_back(obj); }
 274
 275   // Get input file information with an open (possibly re-opened)
 276   // file descriptor.
 277   ld_plugin_status
 278   get_input_file(unsigned int handle, struct ld_plugin_input_file* file);
 279
 280   ld_plugin_status
 281   get_view(unsigned int handle, const void **viewp);
 282
 283   // Release an input file.
 284   ld_plugin_status
 285   release_input_file(unsigned int handle);
 286
 287   // Add a new input file.
 288   ld_plugin_status
 289   add_input_file(const char* pathname, bool is_lib);
 290
 291   // Set the extra library path.
 292   ld_plugin_status
 293   set_extra_library_path(const char* path);
 294
 295   // Return TRUE if we are in the replacement phase.
 296   bool
 297   in_replacement_phase() const
 298   { return this->in_replacement_phase_; }
 299
 300   Input_objects*
 301   input_objects() const
 302   { return this->input_objects_; }
 303
 304   Symbol_table*
 305   symtab()
 306   { return this->symtab_; }
 307
 308   Layout*
 309   layout()
 310   { return this->layout_; }
 311
 312  private:
 313   Plugin_manager(const Plugin_manager&);
 314   Plugin_manager& operator=(const Plugin_manager&);
 315
 316   // Plugin_rescan is a Task which calls the private rescan method.
 317   friend class Plugin_rescan;
 318
 319   // An archive or input group which may have to be rescanned if a
 320   // plugin adds a new file.
 321   struct Rescannable
 322   {
 323     bool is_archive;
 324     union
 325     {
 326       Archive* archive;
 327       Input_group* input_group;
 328     } u;
 329
 330     Rescannable(Archive* archive)
 331       : is_archive(true)
 332     { this->u.archive = archive; }
 333
 334     Rescannable(Input_group* input_group)
 335       : is_archive(false)
 336     { this->u.input_group = input_group; }
 337   };
 338
 339   typedef std::list<Plugin*> Plugin_list;
 340   typedef std::vector<Object*> Object_list;
 341   typedef std::vector<Relobj*> Deferred_layout_list;
 342   typedef std::vector<Rescannable> Rescannable_list;
 343   typedef std::vector<Symbol*> Undefined_symbol_list;
 344
 345   // Rescan archives for undefined symbols.
 346   void
 347   rescan(Task*);
 348
 349   // See whether the rescannable at index I defines SYM.
 350   bool
 351   rescannable_defines(size_t i, Symbol* sym);
 352
 353   // The list of plugin libraries.
 354   Plugin_list plugins_;
 355   // A pointer to the current plugin.  Used while loading plugins.
 356   Plugin_list::iterator current_;
 357
 358   // The list of plugin objects.  The index of an item in this list
 359   // serves as the "handle" that we pass to the plugins.
 360   Object_list objects_;
 361
 362   // The list of regular objects whose layout has been deferred.
 363   Deferred_layout_list deferred_layout_objects_;
 364
 365   // The file currently up for claim by the plugins.
 366   Input_file* input_file_;
 367   struct ld_plugin_input_file plugin_input_file_;
 368
 369   // A list of archives and input groups being saved for possible
 370   // later rescanning.
 371   Rescannable_list rescannable_;
 372
 373   // A list of undefined symbols found in added files.
 374   Undefined_symbol_list undefined_symbols_;
 375
 376   // Whether any input files have been claimed by a plugin.
 377   bool any_claimed_;
 378
 379   // Set to true after the all symbols read event; indicates that we
 380   // are processing replacement files whose symbols should replace the
 381   // placeholder symbols from the Pluginobj objects.
 382   bool in_replacement_phase_;
 383
 384   // Whether any input files or libraries were added by a plugin.
 385   bool any_added_;
 386
 387   // Set to true when the claim_file handler of a plugin is called.
 388   bool in_claim_file_handler_;
 389
 390   const General_options& options_;
 391   Workqueue* workqueue_;
 392   Task* task_;
 393   Input_objects* input_objects_;
 394   Symbol_table* symtab_;
 395   Layout* layout_;
 396   Dirsearch* dirpath_;
 397   Mapfile* mapfile_;
 398   Task_token* this_blocker_;
 399
 400   // An extra directory to search for the libraries passed by
 401   // add_input_library.
 402   std::string extra_search_path_;
 403   Lock* lock_;
 404   Initialize_lock initialize_lock_;
 405 };
 406
 407
 408 // An object file claimed by a plugin.  This is an abstract base class.
 409 // The implementation is the template class Sized_pluginobj.
 410
 411 class Pluginobj : public Object
 412 {
 413  public:
 414
 415   typedef std::vector<Symbol*> Symbols;
 416
 417   Pluginobj(const std::string& name, Input_file* input_file, off_t offset,
 418             off_t filesize);
 419
 420   // Fill in the symbol resolution status for the given plugin symbols.
 421   ld_plugin_status
 422   get_symbol_resolution_info(Symbol_table* symtab,
 423                              int nsyms,
 424                              ld_plugin_symbol* syms,
 425                              int version) const;
 426
 427   // Store the incoming symbols from the plugin for later processing.
 428   void
 429   store_incoming_symbols(int nsyms, const struct ld_plugin_symbol* syms)
 430   {
 431     this->nsyms_ = nsyms;
 432     this->syms_ = syms;
 433   }
 434
 435   // Return TRUE if the comdat group with key COMDAT_KEY from this object
 436   // should be kept.
 437   bool
 438   include_comdat_group(std::string comdat_key, Layout* layout);
 439
 440   // Return the filename.
 441   const std::string&
 442   filename() const
 443   { return this->input_file()->filename(); }
 444
 445   // Return the file descriptor.
 446   int
 447   descriptor()
 448   { return this->input_file()->file().descriptor(); }
 449
 450   // Return the size of the file or archive member.
 451   off_t
 452   filesize()
 453   { return this->filesize_; }
 454
 455   // Return the word size of the object file.
 456   int
 457   elfsize() const
 458   { gold_unreachable(); }
 459
 460   // Return TRUE if this is a big-endian object file.
 461   bool
 462   is_big_endian() const
 463   { gold_unreachable(); }
 464
 465  protected:
 466   // Return TRUE if this is an object claimed by a plugin.
 467   virtual Pluginobj*
 468   do_pluginobj()
 469   { return this; }
 470
 471   // The number of symbols provided by the plugin.
 472   int nsyms_;
 473
 474   // The symbols provided by the plugin.
 475   const struct ld_plugin_symbol* syms_;
 476
 477   // The entries in the symbol table for the external symbols.
 478   Symbols symbols_;
 479
 480  private:
 481   // Size of the file (or archive member).
 482   off_t filesize_;
 483   // Map a comdat key symbol to a boolean indicating whether the comdat
 484   // group in this object with that key should be kept.
 485   typedef Unordered_map<std::string, bool> Comdat_map;
 486   Comdat_map comdat_map_;
 487 };
 488
 489 // A plugin object, size-specific version.
 490
 491 template<int size, bool big_endian>
 492 class Sized_pluginobj : public Pluginobj
 493 {
 494  public:
 495   Sized_pluginobj(const std::string& name, Input_file* input_file,
 496                   off_t offset, off_t filesize);
 497
 498   // Read the symbols.
 499   void
 500   do_read_symbols(Read_symbols_data*);
 501
 502   // Lay out the input sections.
 503   void
 504   do_layout(Symbol_table*, Layout*, Read_symbols_data*);
 505
 506   // Add the symbols to the symbol table.
 507   void
 508   do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*);
 509
 510   Archive::Should_include
 511   do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*,
 512                            std::string* why);
 513
 514   // Iterate over global symbols, calling a visitor class V for each.
 515   void
 516   do_for_all_global_symbols(Read_symbols_data* sd,
 517                             Library_base::Symbol_visitor_base* v);
 518
 519   // Iterate over local symbols, calling a visitor class V for each GOT offset
 520   // associated with a local symbol.
 521   void
 522   do_for_all_local_got_entries(Got_offset_list::Visitor* v) const;
 523
 524   // Get the size of a section.
 525   uint64_t
 526   do_section_size(unsigned int shndx);
 527
 528   // Get the name of a section.
 529   std::string
 530   do_section_name(unsigned int shndx) const;
 531
 532   // Return a view of the contents of a section.
 533   const unsigned char*
 534   do_section_contents(unsigned int shndx, section_size_type* plen,
 535                       bool cache);
 536
 537   // Return section flags.
 538   uint64_t
 539   do_section_flags(unsigned int shndx);
 540
 541   // Return section entsize.
 542   uint64_t
 543   do_section_entsize(unsigned int shndx);
 544
 545   // Return section address.
 546   uint64_t
 547   do_section_address(unsigned int shndx);
 548
 549   // Return section type.
 550   unsigned int
 551   do_section_type(unsigned int shndx);
 552
 553   // Return the section link field.
 554   unsigned int
 555   do_section_link(unsigned int shndx);
 556
 557   // Return the section link field.
 558   unsigned int
 559   do_section_info(unsigned int shndx);
 560
 561   // Return the section alignment.
 562   uint64_t
 563   do_section_addralign(unsigned int shndx);
 564
 565   // Return the Xindex structure to use.
 566   Xindex*
 567   do_initialize_xindex();
 568
 569   // Get symbol counts.
 570   void
 571   do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;
 572
 573   // Get global symbols.
 574   const Symbols*
 575   do_get_global_symbols() const;
 576
 577   // Add placeholder symbols from a claimed file.
 578   ld_plugin_status
 579   add_symbols_from_plugin(int nsyms, const ld_plugin_symbol* syms);
 580
 581  protected:
 582
 583  private:
 584 };
 585
 586 // This Task handles handles the "all symbols read" event hook.
 587 // The plugin may add additional input files at this time, which must
 588 // be queued for reading.
 589
 590 class Plugin_hook : public Task
 591 {
 592  public:
 593   Plugin_hook(const General_options& options, Input_objects* input_objects,
 594               Symbol_table* symtab, Layout* /*layout*/, Dirsearch* dirpath,
 595               Mapfile* mapfile, Task_token* this_blocker,
 596               Task_token* next_blocker)
 597     : options_(options), input_objects_(input_objects), symtab_(symtab),
 598       dirpath_(dirpath), mapfile_(mapfile),
 599       this_blocker_(this_blocker), next_blocker_(next_blocker)
 600   { }
 601
 602   ~Plugin_hook();
 603
 604   // The standard Task methods.
 605
 606   Task_token*
 607   is_runnable();
 608
 609   void
 610   locks(Task_locker*);
 611
 612   void
 613   run(Workqueue*);
 614
 615   std::string
 616   get_name() const
 617   { return "Plugin_hook"; }
 618
 619  private:
 620   const General_options& options_;
 621   Input_objects* input_objects_;
 622   Symbol_table* symtab_;
 623   Dirsearch* dirpath_;
 624   Mapfile* mapfile_;
 625   Task_token* this_blocker_;
 626   Task_token* next_blocker_;
 627 };
 628
 629 } // End namespace gold.
 630
 631 #endif // !defined(GOLD_PLUGIN_H)