| 1 | // archive.cc -- archive support for gold |
| 2 | |
| 3 | #include "gold.h" |
| 4 | |
| 5 | #include <cerrno> |
| 6 | #include <cstring> |
| 7 | #include <climits> |
| 8 | #include <vector> |
| 9 | |
| 10 | #include "elfcpp.h" |
| 11 | #include "fileread.h" |
| 12 | #include "readsyms.h" |
| 13 | #include "symtab.h" |
| 14 | #include "object.h" |
| 15 | #include "archive.h" |
| 16 | |
| 17 | namespace gold |
| 18 | { |
| 19 | |
| 20 | // The header of an entry in the archive. This is all readable text, |
| 21 | // padded with spaces where necesary. If the contents of an archive |
| 22 | // are all text file, the entire archive is readable. |
| 23 | |
| 24 | struct Archive::Archive_header |
| 25 | { |
| 26 | // The entry name. |
| 27 | char ar_name[16]; |
| 28 | // The file modification time. |
| 29 | char ar_date[12]; |
| 30 | // The user's UID in decimal. |
| 31 | char ar_uid[6]; |
| 32 | // The user's GID in decimal. |
| 33 | char ar_gid[6]; |
| 34 | // The file mode in octal. |
| 35 | char ar_mode[8]; |
| 36 | // The file size in decimal. |
| 37 | char ar_size[10]; |
| 38 | // The final magic code. |
| 39 | char ar_fmag[2]; |
| 40 | }; |
| 41 | |
| 42 | // Archive methods. |
| 43 | |
| 44 | const char Archive::armag[sarmag] = |
| 45 | { |
| 46 | '!', '<', 'a', 'r', 'c', 'h', '>', '\n' |
| 47 | }; |
| 48 | |
| 49 | const char Archive::arfmag[2] = { '`', '\n' }; |
| 50 | |
| 51 | // Set up the archive: read the symbol map and the extended name |
| 52 | // table. |
| 53 | |
| 54 | void |
| 55 | Archive::setup() |
| 56 | { |
| 57 | // The first member of the archive should be the symbol table. |
| 58 | std::string armap_name; |
| 59 | off_t armap_size = this->read_header(sarmag, &armap_name); |
| 60 | if (!armap_name.empty()) |
| 61 | { |
| 62 | fprintf(stderr, _("%s: %s: no archive symbol table (run ranlib)\n"), |
| 63 | program_name, this->name().c_str()); |
| 64 | gold_exit(false); |
| 65 | } |
| 66 | |
| 67 | // Read in the entire armap. |
| 68 | const unsigned char* p = this->get_view(sarmag + sizeof(Archive_header), |
| 69 | armap_size); |
| 70 | |
| 71 | // Numbers in the armap are always big-endian. |
| 72 | const elfcpp::Elf_Word* pword = reinterpret_cast<const elfcpp::Elf_Word*>(p); |
| 73 | unsigned int nsyms = elfcpp::Swap<32, true>::readval(pword); |
| 74 | ++pword; |
| 75 | |
| 76 | // Note that the addition is in units of sizeof(elfcpp::Elf_Word). |
| 77 | const char* pnames = reinterpret_cast<const char*>(pword + nsyms); |
| 78 | |
| 79 | this->armap_.resize(nsyms); |
| 80 | |
| 81 | for (unsigned int i = 0; i < nsyms; ++i) |
| 82 | { |
| 83 | this->armap_[i].name = pnames; |
| 84 | this->armap_[i].offset = elfcpp::Swap<32, true>::readval(pword); |
| 85 | pnames += strlen(pnames) + 1; |
| 86 | ++pword; |
| 87 | } |
| 88 | |
| 89 | if (reinterpret_cast<const unsigned char*>(pnames) - p > armap_size) |
| 90 | { |
| 91 | fprintf(stderr, _("%s: %s: bad archive symbol table names\n"), |
| 92 | program_name, this->name().c_str()); |
| 93 | gold_exit(false); |
| 94 | } |
| 95 | |
| 96 | // See if there is an extended name table. |
| 97 | off_t off = sarmag + sizeof(Archive_header) + armap_size; |
| 98 | if ((off & 1) != 0) |
| 99 | ++off; |
| 100 | std::string xname; |
| 101 | off_t extended_size = this->read_header(off, &xname); |
| 102 | if (xname == "/") |
| 103 | { |
| 104 | p = this->get_view(off + sizeof(Archive_header), extended_size); |
| 105 | const char* px = reinterpret_cast<const char*>(p); |
| 106 | this->extended_names_.assign(px, extended_size); |
| 107 | } |
| 108 | |
| 109 | // This array keeps track of which symbols are for archive elements |
| 110 | // which we have already included in the link. |
| 111 | this->seen_.resize(nsyms); |
| 112 | |
| 113 | // Opening the file locked it. Unlock it now. |
| 114 | this->input_file_->file().unlock(); |
| 115 | } |
| 116 | |
| 117 | // Read the header of an archive member at OFF. Fail if something |
| 118 | // goes wrong. Return the size of the member. Set *PNAME to the name |
| 119 | // of the member. |
| 120 | |
| 121 | off_t |
| 122 | Archive::read_header(off_t off, std::string* pname) |
| 123 | { |
| 124 | const unsigned char* p = this->get_view(off, sizeof(Archive_header)); |
| 125 | const Archive_header* hdr = reinterpret_cast<const Archive_header*>(p); |
| 126 | |
| 127 | if (memcmp(hdr->ar_fmag, arfmag, sizeof arfmag) != 0) |
| 128 | { |
| 129 | fprintf(stderr, _("%s; %s: malformed archive header at %ld\n"), |
| 130 | program_name, this->name().c_str(), |
| 131 | static_cast<long>(off)); |
| 132 | gold_exit(false); |
| 133 | } |
| 134 | |
| 135 | const int size_string_size = sizeof hdr->ar_size; |
| 136 | char size_string[size_string_size + 1]; |
| 137 | memcpy(size_string, hdr->ar_size, size_string_size); |
| 138 | char* ps = size_string + size_string_size; |
| 139 | while (ps[-1] == ' ') |
| 140 | --ps; |
| 141 | *ps = '\0'; |
| 142 | |
| 143 | errno = 0; |
| 144 | char* end; |
| 145 | off_t member_size = strtol(size_string, &end, 10); |
| 146 | if (*end != '\0' |
| 147 | || member_size < 0 |
| 148 | || (member_size == LONG_MAX && errno == ERANGE)) |
| 149 | { |
| 150 | fprintf(stderr, _("%s: %s: malformed archive header size at %ld\n"), |
| 151 | program_name, this->name().c_str(), |
| 152 | static_cast<long>(off)); |
| 153 | gold_exit(false); |
| 154 | } |
| 155 | |
| 156 | if (hdr->ar_name[0] != '/') |
| 157 | { |
| 158 | const char* name_end = strchr(hdr->ar_name, '/'); |
| 159 | if (name_end == NULL |
| 160 | || name_end - hdr->ar_name >= static_cast<int>(sizeof hdr->ar_name)) |
| 161 | { |
| 162 | fprintf(stderr, _("%s: %s: malformed archive header name at %ld\n"), |
| 163 | program_name, this->name().c_str(), |
| 164 | static_cast<long>(off)); |
| 165 | gold_exit(false); |
| 166 | } |
| 167 | pname->assign(hdr->ar_name, name_end - hdr->ar_name); |
| 168 | } |
| 169 | else if (hdr->ar_name[1] == ' ') |
| 170 | { |
| 171 | // This is the symbol table. |
| 172 | pname->clear(); |
| 173 | } |
| 174 | else if (hdr->ar_name[1] == '/') |
| 175 | { |
| 176 | // This is the extended name table. |
| 177 | pname->assign(1, '/'); |
| 178 | } |
| 179 | else |
| 180 | { |
| 181 | errno = 0; |
| 182 | long x = strtol(hdr->ar_name + 1, &end, 10); |
| 183 | if (*end != ' ' |
| 184 | || x < 0 |
| 185 | || (x == LONG_MAX && errno == ERANGE) |
| 186 | || static_cast<size_t>(x) >= this->extended_names_.size()) |
| 187 | { |
| 188 | fprintf(stderr, _("%s: %s: bad extended name index at %ld\n"), |
| 189 | program_name, this->name().c_str(), |
| 190 | static_cast<long>(off)); |
| 191 | gold_exit(false); |
| 192 | } |
| 193 | |
| 194 | const char* name = this->extended_names_.data() + x; |
| 195 | const char* name_end = strchr(name, '/'); |
| 196 | if (static_cast<size_t>(name_end - name) > this->extended_names_.size() |
| 197 | || name_end[1] != '\n') |
| 198 | { |
| 199 | fprintf(stderr, _("%s: %s: bad extended name entry at header %ld\n"), |
| 200 | program_name, this->name().c_str(), |
| 201 | static_cast<long>(off)); |
| 202 | gold_exit(false); |
| 203 | } |
| 204 | pname->assign(name, name_end - name); |
| 205 | } |
| 206 | |
| 207 | return member_size; |
| 208 | } |
| 209 | |
| 210 | // Select members from the archive and add them to the link. We walk |
| 211 | // through the elements in the archive map, and look each one up in |
| 212 | // the symbol table. If it exists as a strong undefined symbol, we |
| 213 | // pull in the corresponding element. We have to do this in a loop, |
| 214 | // since pulling in one element may create new undefined symbols which |
| 215 | // may be satisfied by other objects in the archive. |
| 216 | |
| 217 | void |
| 218 | Archive::add_symbols(const General_options& options, Symbol_table* symtab, |
| 219 | Layout* layout, Input_objects* input_objects) |
| 220 | { |
| 221 | const size_t armap_size = this->armap_.size(); |
| 222 | |
| 223 | bool added_new_object; |
| 224 | do |
| 225 | { |
| 226 | added_new_object = false; |
| 227 | off_t last = -1; |
| 228 | for (size_t i = 0; i < armap_size; ++i) |
| 229 | { |
| 230 | if (this->seen_[i]) |
| 231 | continue; |
| 232 | if (this->armap_[i].offset == last) |
| 233 | { |
| 234 | this->seen_[i] = true; |
| 235 | continue; |
| 236 | } |
| 237 | |
| 238 | Symbol* sym = symtab->lookup(this->armap_[i].name); |
| 239 | if (sym == NULL) |
| 240 | continue; |
| 241 | else if (!sym->is_undefined()) |
| 242 | { |
| 243 | this->seen_[i] = true; |
| 244 | continue; |
| 245 | } |
| 246 | else if (sym->binding() == elfcpp::STB_WEAK) |
| 247 | continue; |
| 248 | |
| 249 | // We want to include this object in the link. |
| 250 | last = this->armap_[i].offset; |
| 251 | this->include_member(options, symtab, layout, input_objects, last); |
| 252 | this->seen_[i] = true; |
| 253 | added_new_object = true; |
| 254 | } |
| 255 | } |
| 256 | while (added_new_object); |
| 257 | } |
| 258 | |
| 259 | // Include an archive member in the link. OFF is the file offset of |
| 260 | // the member header. |
| 261 | |
| 262 | void |
| 263 | Archive::include_member(const General_options& options, Symbol_table* symtab, |
| 264 | Layout* layout, Input_objects* input_objects, |
| 265 | off_t off) |
| 266 | { |
| 267 | std::string n; |
| 268 | this->read_header(off, &n); |
| 269 | |
| 270 | size_t memoff = off + sizeof(Archive_header); |
| 271 | |
| 272 | // Read enough of the file to pick up the entire ELF header. |
| 273 | int ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size; |
| 274 | off_t bytes; |
| 275 | const unsigned char* p = this->input_file_->file().get_view(memoff, |
| 276 | ehdr_size, |
| 277 | &bytes); |
| 278 | if (bytes < 4) |
| 279 | { |
| 280 | fprintf(stderr, _("%s: %s: member at %ld is not an ELF object"), |
| 281 | program_name, this->name().c_str(), |
| 282 | static_cast<long>(off)); |
| 283 | gold_exit(false); |
| 284 | } |
| 285 | |
| 286 | static unsigned char elfmagic[4] = |
| 287 | { |
| 288 | elfcpp::ELFMAG0, elfcpp::ELFMAG1, |
| 289 | elfcpp::ELFMAG2, elfcpp::ELFMAG3 |
| 290 | }; |
| 291 | if (memcmp(p, elfmagic, 4) != 0) |
| 292 | { |
| 293 | fprintf(stderr, _("%s: %s: member at %ld is not an ELF object"), |
| 294 | program_name, this->name().c_str(), |
| 295 | static_cast<long>(off)); |
| 296 | gold_exit(false); |
| 297 | } |
| 298 | |
| 299 | Object* obj = make_elf_object((std::string(this->input_file_->filename()) |
| 300 | + "(" + n + ")"), |
| 301 | this->input_file_, memoff, p, bytes); |
| 302 | |
| 303 | input_objects->add_object(obj); |
| 304 | |
| 305 | Read_symbols_data sd; |
| 306 | obj->read_symbols(&sd); |
| 307 | obj->layout(options, symtab, layout, &sd); |
| 308 | obj->add_symbols(symtab, &sd); |
| 309 | } |
| 310 | |
| 311 | // Add_archive_symbols methods. |
| 312 | |
| 313 | Add_archive_symbols::~Add_archive_symbols() |
| 314 | { |
| 315 | if (this->this_blocker_ != NULL) |
| 316 | delete this->this_blocker_; |
| 317 | // next_blocker_ is deleted by the task associated with the next |
| 318 | // input file. |
| 319 | } |
| 320 | |
| 321 | // Return whether we can add the archive symbols. We are blocked by |
| 322 | // this_blocker_. We block next_blocker_. We also lock the file. |
| 323 | |
| 324 | Task::Is_runnable_type |
| 325 | Add_archive_symbols::is_runnable(Workqueue*) |
| 326 | { |
| 327 | if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked()) |
| 328 | return IS_BLOCKED; |
| 329 | return IS_RUNNABLE; |
| 330 | } |
| 331 | |
| 332 | class Add_archive_symbols::Add_archive_symbols_locker : public Task_locker |
| 333 | { |
| 334 | public: |
| 335 | Add_archive_symbols_locker(Task_token& token, Workqueue* workqueue, |
| 336 | File_read& file) |
| 337 | : blocker_(token, workqueue), filelock_(file) |
| 338 | { } |
| 339 | |
| 340 | private: |
| 341 | Task_locker_block blocker_; |
| 342 | Task_locker_obj<File_read> filelock_; |
| 343 | }; |
| 344 | |
| 345 | Task_locker* |
| 346 | Add_archive_symbols::locks(Workqueue* workqueue) |
| 347 | { |
| 348 | return new Add_archive_symbols_locker(*this->next_blocker_, |
| 349 | workqueue, |
| 350 | this->archive_->file()); |
| 351 | } |
| 352 | |
| 353 | void |
| 354 | Add_archive_symbols::run(Workqueue*) |
| 355 | { |
| 356 | this->archive_->add_symbols(this->options_, this->symtab_, this->layout_, |
| 357 | this->input_objects_); |
| 358 | |
| 359 | if (this->input_group_ != NULL) |
| 360 | this->input_group_->add_archive(this->archive_); |
| 361 | else |
| 362 | { |
| 363 | // We no longer need to know about this archive. |
| 364 | delete this->archive_; |
| 365 | } |
| 366 | } |
| 367 | |
| 368 | } // End namespace gold. |