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 "mapfile.h"
  35 #include "fileread.h"
  36 #include "readsyms.h"
  37 #include "symtab.h"
  38 #include "object.h"
  39 #include "archive.h"
  40
  41 namespace gold
  42 {
  43
  44 // The header of an entry in the archive.  This is all readable text,
  45 // padded with spaces where necesary.  If the contents of an archive
  46 // are all text file, the entire archive is readable.
  47
  48 struct Archive::Archive_header
  49 {
  50   // The entry name.
  51   char ar_name[16];
  52   // The file modification time.
  53   char ar_date[12];
  54   // The user's UID in decimal.
  55   char ar_uid[6];
  56   // The user's GID in decimal.
  57   char ar_gid[6];
  58   // The file mode in octal.
  59   char ar_mode[8];
  60   // The file size in decimal.
  61   char ar_size[10];
  62   // The final magic code.
  63   char ar_fmag[2];
  64 };
  65
  66 // Archive methods.
  67
  68 const char Archive::armag[sarmag] =
  69 {
  70   '!', '<', 'a', 'r', 'c', 'h', '>', '\n'
  71 };
  72
  73 const char Archive::armagt[sarmag] =
  74 {
  75   '!', '<', 't', 'h', 'i', 'n', '>', '\n'
  76 };
  77
  78 const char Archive::arfmag[2] = { '`', '\n' };
  79
  80 // Set up the archive: read the symbol map and the extended name
  81 // table.
  82
  83 void
  84 Archive::setup()
  85 {
  86   // We need to ignore empty archives.
  87   if (this->input_file_->file().filesize() == sarmag)
  88     return;
  89
  90   // The first member of the archive should be the symbol table.
  91   std::string armap_name;
  92   section_size_type armap_size =
  93     convert_to_section_size_type(this->read_header(sarmag, false,
  94                                                    &armap_name, NULL));
  95   off_t off = sarmag;
  96   if (armap_name.empty())
  97     {
  98       this->read_armap(sarmag + sizeof(Archive_header), armap_size);
  99       off = sarmag + sizeof(Archive_header) + armap_size;
 100     }
 101   else if (!this->input_file_->options().whole_archive())
 102     gold_error(_("%s: no archive symbol table (run ranlib)"),
 103                this->name().c_str());
 104
 105   // See if there is an extended name table.  We cache these views
 106   // because it is likely that we will want to read the following
 107   // header in the add_symbols routine.
 108   if ((off & 1) != 0)
 109     ++off;
 110   std::string xname;
 111   section_size_type extended_size =
 112     convert_to_section_size_type(this->read_header(off, true, &xname, NULL));
 113   if (xname == "/")
 114     {
 115       const unsigned char* p = this->get_view(off + sizeof(Archive_header),
 116                                               extended_size, false, true);
 117       const char* px = reinterpret_cast<const char*>(p);
 118       this->extended_names_.assign(px, extended_size);
 119     }
 120 }
 121
 122 // Unlock any nested archives.
 123
 124 void
 125 Archive::unlock_nested_archives()
 126 {
 127   for (Nested_archive_table::iterator p = this->nested_archives_.begin();
 128        p != this->nested_archives_.end();
 129        ++p)
 130     {
 131       p->second->unlock(this->task_);
 132     }
 133 }
 134
 135 // Read the archive symbol map.
 136
 137 void
 138 Archive::read_armap(off_t start, section_size_type size)
 139 {
 140   // Read in the entire armap.
 141   const unsigned char* p = this->get_view(start, size, true, false);
 142
 143   // Numbers in the armap are always big-endian.
 144   const elfcpp::Elf_Word* pword = reinterpret_cast<const elfcpp::Elf_Word*>(p);
 145   unsigned int nsyms = elfcpp::Swap<32, true>::readval(pword);
 146   ++pword;
 147
 148   // Note that the addition is in units of sizeof(elfcpp::Elf_Word).
 149   const char* pnames = reinterpret_cast<const char*>(pword + nsyms);
 150   section_size_type names_size =
 151     reinterpret_cast<const char*>(p) + size - pnames;
 152   this->armap_names_.assign(pnames, names_size);
 153
 154   this->armap_.resize(nsyms);
 155
 156   section_offset_type name_offset = 0;
 157   for (unsigned int i = 0; i < nsyms; ++i)
 158     {
 159       this->armap_[i].name_offset = name_offset;
 160       this->armap_[i].file_offset = elfcpp::Swap<32, true>::readval(pword);
 161       name_offset += strlen(pnames + name_offset) + 1;
 162       ++pword;
 163     }
 164
 165   if (static_cast<section_size_type>(name_offset) > names_size)
 166     gold_error(_("%s: bad archive symbol table names"),
 167                this->name().c_str());
 168
 169   // This array keeps track of which symbols are for archive elements
 170   // which we have already included in the link.
 171   this->armap_checked_.resize(nsyms);
 172 }
 173
 174 // Read the header of an archive member at OFF.  Fail if something
 175 // goes wrong.  Return the size of the member.  Set *PNAME to the name
 176 // of the member.
 177
 178 off_t
 179 Archive::read_header(off_t off, bool cache, std::string* pname,
 180                      off_t* nested_off)
 181 {
 182   const unsigned char* p = this->get_view(off, sizeof(Archive_header), true,
 183                                           cache);
 184   const Archive_header* hdr = reinterpret_cast<const Archive_header*>(p);
 185   return this->interpret_header(hdr, off,  pname, nested_off);
 186 }
 187
 188 // Interpret the header of HDR, the header of the archive member at
 189 // file offset OFF.  Fail if something goes wrong.  Return the size of
 190 // the member.  Set *PNAME to the name of the member.
 191
 192 off_t
 193 Archive::interpret_header(const Archive_header* hdr, off_t off,
 194                           std::string* pname, off_t* nested_off)
 195 {
 196   if (memcmp(hdr->ar_fmag, arfmag, sizeof arfmag) != 0)
 197     {
 198       gold_error(_("%s: malformed archive header at %zu"),
 199                  this->name().c_str(), static_cast<size_t>(off));
 200       return this->input_file_->file().filesize() - off;
 201     }
 202
 203   const int size_string_size = sizeof hdr->ar_size;
 204   char size_string[size_string_size + 1];
 205   memcpy(size_string, hdr->ar_size, size_string_size);
 206   char* ps = size_string + size_string_size;
 207   while (ps[-1] == ' ')
 208     --ps;
 209   *ps = '\0';
 210
 211   errno = 0;
 212   char* end;
 213   off_t member_size = strtol(size_string, &end, 10);
 214   if (*end != '\0'
 215       || member_size < 0
 216       || (member_size == LONG_MAX && errno == ERANGE))
 217     {
 218       gold_error(_("%s: malformed archive header size at %zu"),
 219                  this->name().c_str(), static_cast<size_t>(off));
 220       return this->input_file_->file().filesize() - off;
 221     }
 222
 223   if (hdr->ar_name[0] != '/')
 224     {
 225       const char* name_end = strchr(hdr->ar_name, '/');
 226       if (name_end == NULL
 227           || name_end - hdr->ar_name >= static_cast<int>(sizeof hdr->ar_name))
 228         {
 229           gold_error(_("%s: malformed archive header name at %zu"),
 230                      this->name().c_str(), static_cast<size_t>(off));
 231           return this->input_file_->file().filesize() - off;
 232         }
 233       pname->assign(hdr->ar_name, name_end - hdr->ar_name);
 234       if (nested_off != NULL)
 235         *nested_off = 0;
 236     }
 237   else if (hdr->ar_name[1] == ' ')
 238     {
 239       // This is the symbol table.
 240       pname->clear();
 241     }
 242   else if (hdr->ar_name[1] == '/')
 243     {
 244       // This is the extended name table.
 245       pname->assign(1, '/');
 246     }
 247   else
 248     {
 249       errno = 0;
 250       long x = strtol(hdr->ar_name + 1, &end, 10);
 251       long y = 0;
 252       if (*end == ':')
 253         y = strtol(end + 1, &end, 10);
 254       if (*end != ' '
 255           || x < 0
 256           || (x == LONG_MAX && errno == ERANGE)
 257           || static_cast<size_t>(x) >= this->extended_names_.size())
 258         {
 259           gold_error(_("%s: bad extended name index at %zu"),
 260                      this->name().c_str(), static_cast<size_t>(off));
 261           return this->input_file_->file().filesize() - off;
 262         }
 263
 264       const char* name = this->extended_names_.data() + x;
 265       const char* name_end = strchr(name, '\n');
 266       if (static_cast<size_t>(name_end - name) > this->extended_names_.size()
 267           || name_end[-1] != '/')
 268         {
 269           gold_error(_("%s: bad extended name entry at header %zu"),
 270                      this->name().c_str(), static_cast<size_t>(off));
 271           return this->input_file_->file().filesize() - off;
 272         }
 273       pname->assign(name, name_end - 1 - name);
 274       if (nested_off != NULL)
 275         *nested_off = y;
 276     }
 277
 278   return member_size;
 279 }
 280
 281 // Select members from the archive and add them to the link.  We walk
 282 // through the elements in the archive map, and look each one up in
 283 // the symbol table.  If it exists as a strong undefined symbol, we
 284 // pull in the corresponding element.  We have to do this in a loop,
 285 // since pulling in one element may create new undefined symbols which
 286 // may be satisfied by other objects in the archive.
 287
 288 void
 289 Archive::add_symbols(Symbol_table* symtab, Layout* layout,
 290                      Input_objects* input_objects, Mapfile* mapfile)
 291 {
 292   if (this->input_file_->options().whole_archive())
 293     return this->include_all_members(symtab, layout, input_objects,
 294                                      mapfile);
 295
 296   const size_t armap_size = this->armap_.size();
 297
 298   // This is a quick optimization, since we usually see many symbols
 299   // in a row with the same offset.  last_seen_offset holds the last
 300   // offset we saw that was present in the seen_offsets_ set.
 301   off_t last_seen_offset = -1;
 302
 303   // Track which symbols in the symbol table we've already found to be
 304   // defined.
 305
 306   bool added_new_object;
 307   do
 308     {
 309       added_new_object = false;
 310       for (size_t i = 0; i < armap_size; ++i)
 311         {
 312           if (this->armap_checked_[i])
 313             continue;
 314           if (this->armap_[i].file_offset == last_seen_offset)
 315             {
 316               this->armap_checked_[i] = true;
 317               continue;
 318             }
 319           if (this->seen_offsets_.find(this->armap_[i].file_offset)
 320               != this->seen_offsets_.end())
 321             {
 322               this->armap_checked_[i] = true;
 323               last_seen_offset = this->armap_[i].file_offset;
 324               continue;
 325             }
 326
 327           const char* sym_name = (this->armap_names_.data()
 328                                   + this->armap_[i].name_offset);
 329           Symbol* sym = symtab->lookup(sym_name);
 330           if (sym == NULL)
 331             {
 332               // Check whether the symbol was named in a -u option.
 333               if (!parameters->options().is_undefined(sym_name))
 334                 continue;
 335             }
 336           else if (!sym->is_undefined())
 337             {
 338               this->armap_checked_[i] = true;
 339               continue;
 340             }
 341           else if (sym->binding() == elfcpp::STB_WEAK)
 342             continue;
 343
 344           // We want to include this object in the link.
 345           last_seen_offset = this->armap_[i].file_offset;
 346           this->seen_offsets_.insert(last_seen_offset);
 347           this->armap_checked_[i] = true;
 348
 349           std::string why;
 350           if (sym == NULL)
 351             {
 352               why = "-u ";
 353               why += sym_name;
 354             }
 355           this->include_member(symtab, layout, input_objects,
 356                                last_seen_offset, mapfile, sym, why.c_str());
 357
 358           added_new_object = true;
 359         }
 360     }
 361   while (added_new_object);
 362 }
 363
 364 // Include all the archive members in the link.  This is for --whole-archive.
 365
 366 void
 367 Archive::include_all_members(Symbol_table* symtab, Layout* layout,
 368                              Input_objects* input_objects, Mapfile* mapfile)
 369 {
 370   off_t off = sarmag;
 371   off_t filesize = this->input_file_->file().filesize();
 372   while (true)
 373     {
 374       if (filesize - off < static_cast<off_t>(sizeof(Archive_header)))
 375         {
 376           if (filesize != off)
 377             gold_error(_("%s: short archive header at %zu"),
 378                        this->name().c_str(), static_cast<size_t>(off));
 379           break;
 380         }
 381
 382       unsigned char hdr_buf[sizeof(Archive_header)];
 383       this->input_file_->file().read(off, sizeof(Archive_header), hdr_buf);
 384
 385       const Archive_header* hdr =
 386         reinterpret_cast<const Archive_header*>(hdr_buf);
 387       std::string name;
 388       off_t size = this->interpret_header(hdr, off, &name, NULL);
 389       bool special_member = false;
 390       if (name.empty())
 391         {
 392           // Symbol table.
 393           special_member = true;
 394         }
 395       else if (name == "/")
 396         {
 397           // Extended name table.
 398           special_member = true;
 399         }
 400       else
 401         this->include_member(symtab, layout, input_objects, off,
 402                              mapfile, NULL, "--whole-archive");
 403
 404       off += sizeof(Archive_header);
 405       if (special_member || !this->is_thin_archive_)
 406         off += size;
 407       if ((off & 1) != 0)
 408         ++off;
 409     }
 410 }
 411
 412 // Include an archive member in the link.  OFF is the file offset of
 413 // the member header.  WHY is the reason we are including this member.
 414
 415 void
 416 Archive::include_member(Symbol_table* symtab, Layout* layout,
 417                         Input_objects* input_objects, off_t off,
 418                         Mapfile* mapfile, Symbol* sym, const char* why)
 419 {
 420   std::string n;
 421   off_t nested_off;
 422   this->read_header(off, false, &n, &nested_off);
 423
 424   if (mapfile != NULL)
 425     mapfile->report_include_archive_member(this, n, sym, why);
 426
 427   Input_file* input_file;
 428   off_t memoff;
 429
 430   if (!this->is_thin_archive_)
 431     {
 432       input_file = this->input_file_;
 433       memoff = off + static_cast<off_t>(sizeof(Archive_header));
 434     }
 435   else
 436     {
 437       // Adjust a relative pathname so that it is relative
 438       // to the directory containing the archive.
 439       if (!IS_ABSOLUTE_PATH(n.c_str()))
 440         {
 441           const char *arch_path = this->name().c_str();
 442           const char *basename = lbasename(arch_path);
 443           if (basename > arch_path)
 444             n.replace(0, 0, this->name().substr(0, basename - arch_path));
 445         }
 446       if (nested_off > 0)
 447         {
 448           // This is a member of a nested archive.  Open the containing
 449           // archive if we don't already have it open, then do a recursive
 450           // call to include the member from that archive.
 451           Archive* arch;
 452           Nested_archive_table::const_iterator p =
 453             this->nested_archives_.find(n);
 454           if (p != this->nested_archives_.end())
 455             arch = p->second;
 456           else
 457             {
 458               Input_file_argument* input_file_arg =
 459                 new Input_file_argument(n.c_str(), false, "", false,
 460                                         parameters->options());
 461               input_file = new Input_file(input_file_arg);
 462               if (!input_file->open(parameters->options(), *this->dirpath_,
 463                                     this->task_))
 464                 return;
 465               arch = new Archive(n, input_file, false, this->dirpath_,
 466                                  this->task_);
 467               arch->setup();
 468               std::pair<Nested_archive_table::iterator, bool> ins =
 469                 this->nested_archives_.insert(std::make_pair(n, arch));
 470               gold_assert(ins.second);
 471             }
 472           arch->include_member(symtab, layout, input_objects, nested_off,
 473                                NULL, NULL, NULL);
 474           return;
 475         }
 476       // This is an external member of a thin archive.  Open the
 477       // file as a regular relocatable object file.
 478       Input_file_argument* input_file_arg =
 479           new Input_file_argument(n.c_str(), false, "", false,
 480                                   this->input_file_->options());
 481       input_file = new Input_file(input_file_arg);
 482       if (!input_file->open(parameters->options(), *this->dirpath_,
 483                             this->task_))
 484         {
 485           return;
 486         }
 487       memoff = 0;
 488     }
 489
 490   off_t filesize = input_file->file().filesize();
 491   int read_size = elfcpp::Elf_sizes<64>::ehdr_size;
 492   if (filesize - memoff < read_size)
 493     read_size = filesize - memoff;
 494
 495   if (read_size < 4)
 496     {
 497       gold_error(_("%s: member at %zu is not an ELF object"),
 498                  this->name().c_str(), static_cast<size_t>(off));
 499       return;
 500     }
 501
 502   const unsigned char* ehdr = input_file->file().get_view(memoff, 0, read_size,
 503                                                           true, false);
 504
 505   static unsigned char elfmagic[4] =
 506     {
 507       elfcpp::ELFMAG0, elfcpp::ELFMAG1,
 508       elfcpp::ELFMAG2, elfcpp::ELFMAG3
 509     };
 510   if (memcmp(ehdr, elfmagic, 4) != 0)
 511     {
 512       gold_error(_("%s: member at %zu is not an ELF object"),
 513                  this->name().c_str(), static_cast<size_t>(off));
 514       return;
 515     }
 516
 517   Object* obj = make_elf_object((std::string(this->input_file_->filename())
 518                                  + "(" + n + ")"),
 519                                 input_file, memoff, ehdr, read_size);
 520
 521   if (input_objects->add_object(obj))
 522     {
 523       Read_symbols_data sd;
 524       obj->read_symbols(&sd);
 525       obj->layout(symtab, layout, &sd);
 526       obj->add_symbols(symtab, &sd);
 527     }
 528   else
 529     {
 530       // FIXME: We need to close the descriptor here.
 531       delete obj;
 532     }
 533
 534   if (this->is_thin_archive_)
 535     {
 536       // Opening the file locked it.  Unlock it now.
 537       input_file->file().unlock(this->task_);
 538     }
 539 }
 540
 541 // Add_archive_symbols methods.
 542
 543 Add_archive_symbols::~Add_archive_symbols()
 544 {
 545   if (this->this_blocker_ != NULL)
 546     delete this->this_blocker_;
 547   // next_blocker_ is deleted by the task associated with the next
 548   // input file.
 549 }
 550
 551 // Return whether we can add the archive symbols.  We are blocked by
 552 // this_blocker_.  We block next_blocker_.  We also lock the file.
 553
 554 Task_token*
 555 Add_archive_symbols::is_runnable()
 556 {
 557   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 558     return this->this_blocker_;
 559   return NULL;
 560 }
 561
 562 void
 563 Add_archive_symbols::locks(Task_locker* tl)
 564 {
 565   tl->add(this, this->next_blocker_);
 566   tl->add(this, this->archive_->token());
 567 }
 568
 569 void
 570 Add_archive_symbols::run(Workqueue*)
 571 {
 572   this->archive_->add_symbols(this->symtab_, this->layout_,
 573                               this->input_objects_, this->mapfile_);
 574
 575   this->archive_->unlock_nested_archives();
 576
 577   this->archive_->release();
 578   this->archive_->clear_uncached_views();
 579
 580   if (this->input_group_ != NULL)
 581     this->input_group_->add_archive(this->archive_);
 582   else
 583     {
 584       // We no longer need to know about this archive.
 585       delete this->archive_;
 586       this->archive_ = NULL;
 587     }
 588 }
 589
 590 } // End namespace gold.