gold/archive.cc

   1 // archive.cc -- archive support for gold
   2
   3 // Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@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 #include "gold.h"
  24
  25 #include <cerrno>
  26 #include <cstring>
  27 #include <climits>
  28 #include <vector>
  29 #include "libiberty.h"
  30 #include "filenames.h"
  31
  32 #include "elfcpp.h"
  33 #include "options.h"
  34 #include "fileread.h"
  35 #include "readsyms.h"
  36 #include "symtab.h"
  37 #include "object.h"
  38 #include "archive.h"
  39
  40 namespace gold
  41 {
  42
  43 // The header of an entry in the archive.  This is all readable text,
  44 // padded with spaces where necesary.  If the contents of an archive
  45 // are all text file, the entire archive is readable.
  46
  47 struct Archive::Archive_header
  48 {
  49   // The entry name.
  50   char ar_name[16];
  51   // The file modification time.
  52   char ar_date[12];
  53   // The user's UID in decimal.
  54   char ar_uid[6];
  55   // The user's GID in decimal.
  56   char ar_gid[6];
  57   // The file mode in octal.
  58   char ar_mode[8];
  59   // The file size in decimal.
  60   char ar_size[10];
  61   // The final magic code.
  62   char ar_fmag[2];
  63 };
  64
  65 // Archive methods.
  66
  67 const char Archive::armag[sarmag] =
  68 {
  69   '!', '<', 'a', 'r', 'c', 'h', '>', '\n'
  70 };
  71
  72 const char Archive::armagt[sarmag] =
  73 {
  74   '!', '<', 't', 'h', 'i', 'n', '>', '\n'
  75 };
  76
  77 const char Archive::arfmag[2] = { '`', '\n' };
  78
  79 // Set up the archive: read the symbol map and the extended name
  80 // table.
  81
  82 void
  83 Archive::setup()
  84 {
  85   // We need to ignore empty archives.
  86   if (this->input_file_->file().filesize() == sarmag)
  87     return;
  88
  89   // The first member of the archive should be the symbol table.
  90   std::string armap_name;
  91   section_size_type armap_size =
  92     convert_to_section_size_type(this->read_header(sarmag, false,
  93                                                    &armap_name, NULL));
  94   off_t off = sarmag;
  95   if (armap_name.empty())
  96     {
  97       this->read_armap(sarmag + sizeof(Archive_header), armap_size);
  98       off = sarmag + sizeof(Archive_header) + armap_size;
  99     }
 100   else if (!this->input_file_->options().whole_archive())
 101     gold_error(_("%s: no archive symbol table (run ranlib)"),
 102                this->name().c_str());
 103
 104   // See if there is an extended name table.  We cache these views
 105   // because it is likely that we will want to read the following
 106   // header in the add_symbols routine.
 107   if ((off & 1) != 0)
 108     ++off;
 109   std::string xname;
 110   section_size_type extended_size =
 111     convert_to_section_size_type(this->read_header(off, true, &xname, NULL));
 112   if (xname == "/")
 113     {
 114       const unsigned char* p = this->get_view(off + sizeof(Archive_header),
 115                                               extended_size, false, true);
 116       const char* px = reinterpret_cast<const char*>(p);
 117       this->extended_names_.assign(px, extended_size);
 118     }
 119 }
 120
 121 // Unlock any nested archives.
 122
 123 void
 124 Archive::unlock_nested_archives()
 125 {
 126   for (Nested_archive_table::iterator p = this->nested_archives_.begin();
 127        p != this->nested_archives_.end();
 128        ++p)
 129     {
 130       p->second->unlock(this->task_);
 131     }
 132 }
 133
 134 // Read the archive symbol map.
 135
 136 void
 137 Archive::read_armap(off_t start, section_size_type size)
 138 {
 139   // Read in the entire armap.
 140   const unsigned char* p = this->get_view(start, size, true, false);
 141
 142   // Numbers in the armap are always big-endian.
 143   const elfcpp::Elf_Word* pword = reinterpret_cast<const elfcpp::Elf_Word*>(p);
 144   unsigned int nsyms = elfcpp::Swap<32, true>::readval(pword);
 145   ++pword;
 146
 147   // Note that the addition is in units of sizeof(elfcpp::Elf_Word).
 148   const char* pnames = reinterpret_cast<const char*>(pword + nsyms);
 149   section_size_type names_size =
 150     reinterpret_cast<const char*>(p) + size - pnames;
 151   this->armap_names_.assign(pnames, names_size);
 152
 153   this->armap_.resize(nsyms);
 154
 155   section_offset_type name_offset = 0;
 156   for (unsigned int i = 0; i < nsyms; ++i)
 157     {
 158       this->armap_[i].name_offset = name_offset;
 159       this->armap_[i].file_offset = elfcpp::Swap<32, true>::readval(pword);
 160       name_offset += strlen(pnames + name_offset) + 1;
 161       ++pword;
 162     }
 163
 164   if (static_cast<section_size_type>(name_offset) > names_size)
 165     gold_error(_("%s: bad archive symbol table names"),
 166                this->name().c_str());
 167
 168   // This array keeps track of which symbols are for archive elements
 169   // which we have already included in the link.
 170   this->armap_checked_.resize(nsyms);
 171 }
 172
 173 // Read the header of an archive member at OFF.  Fail if something
 174 // goes wrong.  Return the size of the member.  Set *PNAME to the name
 175 // of the member.
 176
 177 off_t
 178 Archive::read_header(off_t off, bool cache, std::string* pname,
 179                      off_t* nested_off)
 180 {
 181   const unsigned char* p = this->get_view(off, sizeof(Archive_header), true,
 182                                           cache);
 183   const Archive_header* hdr = reinterpret_cast<const Archive_header*>(p);
 184   return this->interpret_header(hdr, off,  pname, nested_off);
 185 }
 186
 187 // Interpret the header of HDR, the header of the archive member at
 188 // file offset OFF.  Fail if something goes wrong.  Return the size of
 189 // the member.  Set *PNAME to the name of the member.
 190
 191 off_t
 192 Archive::interpret_header(const Archive_header* hdr, off_t off,
 193                           std::string* pname, off_t* nested_off)
 194 {
 195   if (memcmp(hdr->ar_fmag, arfmag, sizeof arfmag) != 0)
 196     {
 197       gold_error(_("%s: malformed archive header at %zu"),
 198                  this->name().c_str(), static_cast<size_t>(off));
 199       return this->input_file_->file().filesize() - off;
 200     }
 201
 202   const int size_string_size = sizeof hdr->ar_size;
 203   char size_string[size_string_size + 1];
 204   memcpy(size_string, hdr->ar_size, size_string_size);
 205   char* ps = size_string + size_string_size;
 206   while (ps[-1] == ' ')
 207     --ps;
 208   *ps = '\0';
 209
 210   errno = 0;
 211   char* end;
 212   off_t member_size = strtol(size_string, &end, 10);
 213   if (*end != '\0'
 214       || member_size < 0
 215       || (member_size == LONG_MAX && errno == ERANGE))
 216     {
 217       gold_error(_("%s: malformed archive header size at %zu"),
 218                  this->name().c_str(), static_cast<size_t>(off));
 219       return this->input_file_->file().filesize() - off;
 220     }
 221
 222   if (hdr->ar_name[0] != '/')
 223     {
 224       const char* name_end = strchr(hdr->ar_name, '/');
 225       if (name_end == NULL
 226           || name_end - hdr->ar_name >= static_cast<int>(sizeof hdr->ar_name))
 227         {
 228           gold_error(_("%s: malformed archive header name at %zu"),
 229                      this->name().c_str(), static_cast<size_t>(off));
 230           return this->input_file_->file().filesize() - off;
 231         }
 232       pname->assign(hdr->ar_name, name_end - hdr->ar_name);
 233       if (nested_off != NULL)
 234         *nested_off = 0;
 235     }
 236   else if (hdr->ar_name[1] == ' ')
 237     {
 238       // This is the symbol table.
 239       pname->clear();
 240     }
 241   else if (hdr->ar_name[1] == '/')
 242     {
 243       // This is the extended name table.
 244       pname->assign(1, '/');
 245     }
 246   else
 247     {
 248       errno = 0;
 249       long x = strtol(hdr->ar_name + 1, &end, 10);
 250       long y = 0;
 251       if (*end == ':')
 252         y = strtol(end + 1, &end, 10);
 253       if (*end != ' '
 254           || x < 0
 255           || (x == LONG_MAX && errno == ERANGE)
 256           || static_cast<size_t>(x) >= this->extended_names_.size())
 257         {
 258           gold_error(_("%s: bad extended name index at %zu"),
 259                      this->name().c_str(), static_cast<size_t>(off));
 260           return this->input_file_->file().filesize() - off;
 261         }
 262
 263       const char* name = this->extended_names_.data() + x;
 264       const char* name_end = strchr(name, '\n');
 265       if (static_cast<size_t>(name_end - name) > this->extended_names_.size()
 266           || name_end[-1] != '/')
 267         {
 268           gold_error(_("%s: bad extended name entry at header %zu"),
 269                      this->name().c_str(), static_cast<size_t>(off));
 270           return this->input_file_->file().filesize() - off;
 271         }
 272       pname->assign(name, name_end - 1 - name);
 273       if (nested_off != NULL)
 274         *nested_off = y;
 275     }
 276
 277   return member_size;
 278 }
 279
 280 // Select members from the archive and add them to the link.  We walk
 281 // through the elements in the archive map, and look each one up in
 282 // the symbol table.  If it exists as a strong undefined symbol, we
 283 // pull in the corresponding element.  We have to do this in a loop,
 284 // since pulling in one element may create new undefined symbols which
 285 // may be satisfied by other objects in the archive.
 286
 287 void
 288 Archive::add_symbols(Symbol_table* symtab, Layout* layout,
 289                      Input_objects* input_objects)
 290 {
 291   if (this->input_file_->options().whole_archive())
 292     return this->include_all_members(symtab, layout, input_objects);
 293
 294   const size_t armap_size = this->armap_.size();
 295
 296   // This is a quick optimization, since we usually see many symbols
 297   // in a row with the same offset.  last_seen_offset holds the last
 298   // offset we saw that was present in the seen_offsets_ set.
 299   off_t last_seen_offset = -1;
 300
 301   // Track which symbols in the symbol table we've already found to be
 302   // defined.
 303
 304   bool added_new_object;
 305   do
 306     {
 307       added_new_object = false;
 308       for (size_t i = 0; i < armap_size; ++i)
 309         {
 310           if (this->armap_checked_[i])
 311             continue;
 312           if (this->armap_[i].file_offset == last_seen_offset)
 313             {
 314               this->armap_checked_[i] = true;
 315               continue;
 316             }
 317           if (this->seen_offsets_.find(this->armap_[i].file_offset)
 318               != this->seen_offsets_.end())
 319             {
 320               this->armap_checked_[i] = true;
 321               last_seen_offset = this->armap_[i].file_offset;
 322               continue;
 323             }
 324
 325           const char* sym_name = (this->armap_names_.data()
 326                                   + this->armap_[i].name_offset);
 327           Symbol* sym = symtab->lookup(sym_name);
 328           if (sym == NULL)
 329             {
 330               // Check whether the symbol was named in a -u option.
 331               if (!parameters->options().is_undefined(sym_name))
 332                 continue;
 333             }
 334           else if (!sym->is_undefined())
 335             {
 336               this->armap_checked_[i] = true;
 337               continue;
 338             }
 339           else if (sym->binding() == elfcpp::STB_WEAK)
 340             continue;
 341
 342           // We want to include this object in the link.
 343           last_seen_offset = this->armap_[i].file_offset;
 344           this->seen_offsets_.insert(last_seen_offset);
 345           this->armap_checked_[i] = true;
 346           this->include_member(symtab, layout, input_objects,
 347                                last_seen_offset);
 348           added_new_object = true;
 349         }
 350     }
 351   while (added_new_object);
 352 }
 353
 354 // Include all the archive members in the link.  This is for --whole-archive.
 355
 356 void
 357 Archive::include_all_members(Symbol_table* symtab, Layout* layout,
 358                              Input_objects* input_objects)
 359 {
 360   off_t off = sarmag;
 361   off_t filesize = this->input_file_->file().filesize();
 362   while (true)
 363     {
 364       if (filesize - off < static_cast<off_t>(sizeof(Archive_header)))
 365         {
 366           if (filesize != off)
 367             gold_error(_("%s: short archive header at %zu"),
 368                        this->name().c_str(), static_cast<size_t>(off));
 369           break;
 370         }
 371
 372       unsigned char hdr_buf[sizeof(Archive_header)];
 373       this->input_file_->file().read(off, sizeof(Archive_header), hdr_buf);
 374
 375       const Archive_header* hdr =
 376         reinterpret_cast<const Archive_header*>(hdr_buf);
 377       std::string name;
 378       off_t size = this->interpret_header(hdr, off, &name, NULL);
 379       if (name.empty())
 380         {
 381           // Symbol table.
 382         }
 383       else if (name == "/")
 384         {
 385           // Extended name table.
 386         }
 387       else
 388         this->include_member(symtab, layout, input_objects, off);
 389
 390       off += sizeof(Archive_header);
 391       if (!this->is_thin_archive_)
 392         off += size;
 393       if ((off & 1) != 0)
 394         ++off;
 395     }
 396 }
 397
 398 // Include an archive member in the link.  OFF is the file offset of
 399 // the member header.
 400
 401 void
 402 Archive::include_member(Symbol_table* symtab, Layout* layout,
 403                         Input_objects* input_objects, off_t off)
 404 {
 405   std::string n;
 406   off_t nested_off;
 407   this->read_header(off, false, &n, &nested_off);
 408
 409   Input_file* input_file;
 410   off_t memoff;
 411
 412   if (!this->is_thin_archive_)
 413     {
 414       input_file = this->input_file_;
 415       memoff = off + static_cast<off_t>(sizeof(Archive_header));
 416     }
 417   else
 418     {
 419       // Adjust a relative pathname so that it is relative
 420       // to the directory containing the archive.
 421       if (!IS_ABSOLUTE_PATH(n.c_str()))
 422         {
 423           const char *arch_path = this->name().c_str();
 424           const char *basename = lbasename(arch_path);
 425           if (basename > arch_path)
 426             n.replace(0, 0, this->name().substr(0, basename - arch_path));
 427         }
 428       if (nested_off > 0)
 429         {
 430           // This is a member of a nested archive.  Open the containing
 431           // archive if we don't already have it open, then do a recursive
 432           // call to include the member from that archive.
 433           Archive* arch;
 434           Nested_archive_table::const_iterator p =
 435             this->nested_archives_.find(n);
 436           if (p != this->nested_archives_.end())
 437             arch = p->second;
 438           else
 439             {
 440               Input_file_argument* input_file_arg =
 441                 new Input_file_argument(n.c_str(), false, "", false,
 442                                         parameters->options());
 443               input_file = new Input_file(input_file_arg);
 444               if (!input_file->open(parameters->options(), *this->dirpath_,
 445                                     this->task_))
 446                 return;
 447               arch = new Archive(n, input_file, false, this->dirpath_,
 448                                  this->task_);
 449               arch->setup();
 450               std::pair<Nested_archive_table::iterator, bool> ins =
 451                 this->nested_archives_.insert(std::make_pair(n, arch));
 452               gold_assert(ins.second);
 453             }
 454           arch->include_member(symtab, layout, input_objects, nested_off);
 455           return;
 456         }
 457       // This is an external member of a thin archive.  Open the
 458       // file as a regular relocatable object file.
 459       Input_file_argument* input_file_arg =
 460           new Input_file_argument(n.c_str(), false, "", false,
 461                                   this->input_file_->options());
 462       input_file = new Input_file(input_file_arg);
 463       if (!input_file->open(parameters->options(), *this->dirpath_,
 464                             this->task_))
 465         {
 466           return;
 467         }
 468       memoff = 0;
 469     }
 470
 471   off_t filesize = input_file->file().filesize();
 472   int read_size = elfcpp::Elf_sizes<64>::ehdr_size;
 473   if (filesize - memoff < read_size)
 474     read_size = filesize - memoff;
 475
 476   if (read_size < 4)
 477     {
 478       gold_error(_("%s: member at %zu is not an ELF object"),
 479                  this->name().c_str(), static_cast<size_t>(off));
 480       return;
 481     }
 482
 483   const unsigned char* ehdr = input_file->file().get_view(memoff, 0, read_size,
 484                                                           true, false);
 485
 486   static unsigned char elfmagic[4] =
 487     {
 488       elfcpp::ELFMAG0, elfcpp::ELFMAG1,
 489       elfcpp::ELFMAG2, elfcpp::ELFMAG3
 490     };
 491   if (memcmp(ehdr, elfmagic, 4) != 0)
 492     {
 493       gold_error(_("%s: member at %zu is not an ELF object"),
 494                  this->name().c_str(), static_cast<size_t>(off));
 495       return;
 496     }
 497
 498   Object* obj = make_elf_object((std::string(this->input_file_->filename())
 499                                  + "(" + n + ")"),
 500                                 input_file, memoff, ehdr, read_size);
 501
 502   if (input_objects->add_object(obj))
 503     {
 504       Read_symbols_data sd;
 505       obj->read_symbols(&sd);
 506       obj->layout(symtab, layout, &sd);
 507       obj->add_symbols(symtab, &sd);
 508     }
 509   else
 510     {
 511       // FIXME: We need to close the descriptor here.
 512       delete obj;
 513     }
 514
 515   if (this->is_thin_archive_)
 516     {
 517       // Opening the file locked it.  Unlock it now.
 518       input_file->file().unlock(this->task_);
 519     }
 520 }
 521
 522 // Add_archive_symbols methods.
 523
 524 Add_archive_symbols::~Add_archive_symbols()
 525 {
 526   if (this->this_blocker_ != NULL)
 527     delete this->this_blocker_;
 528   // next_blocker_ is deleted by the task associated with the next
 529   // input file.
 530 }
 531
 532 // Return whether we can add the archive symbols.  We are blocked by
 533 // this_blocker_.  We block next_blocker_.  We also lock the file.
 534
 535 Task_token*
 536 Add_archive_symbols::is_runnable()
 537 {
 538   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 539     return this->this_blocker_;
 540   return NULL;
 541 }
 542
 543 void
 544 Add_archive_symbols::locks(Task_locker* tl)
 545 {
 546   tl->add(this, this->next_blocker_);
 547   tl->add(this, this->archive_->token());
 548 }
 549
 550 void
 551 Add_archive_symbols::run(Workqueue*)
 552 {
 553   this->archive_->add_symbols(this->symtab_, this->layout_,
 554                               this->input_objects_);
 555
 556   this->archive_->unlock_nested_archives();
 557
 558   this->archive_->release();
 559   this->archive_->clear_uncached_views();
 560
 561   if (this->input_group_ != NULL)
 562     this->input_group_->add_archive(this->archive_);
 563   else
 564     {
 565       // We no longer need to know about this archive.
 566       delete this->archive_;
 567       this->archive_ = NULL;
 568     }
 569 }
 570
 571 } // End namespace gold.