1 /* 2 * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/classLoader.hpp" 27 #include "classfile/symbolTable.hpp" 28 #include "classfile/altHashing.hpp" 29 #include "memory/filemap.hpp" 30 #include "runtime/arguments.hpp" 31 #include "runtime/java.hpp" 32 #include "runtime/os.hpp" 33 #include "services/memTracker.hpp" 34 #include "utilities/defaultStream.hpp" 35 36 # include <sys/stat.h> 37 # include <errno.h> 38 39 #ifndef O_BINARY // if defined (Win32) use binary files. 40 #define O_BINARY 0 // otherwise do nothing. 41 #endif 42 43 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 44 45 extern address JVM_FunctionAtStart(); 46 extern address JVM_FunctionAtEnd(); 47 48 // Complain and stop. All error conditions occurring during the writing of 49 // an archive file should stop the process. Unrecoverable errors during 50 // the reading of the archive file should stop the process. 51 52 static void fail(const char *msg, va_list ap) { 53 // This occurs very early during initialization: tty is not initialized. 54 jio_fprintf(defaultStream::error_stream(), 55 "An error has occurred while processing the" 56 " shared archive file.\n"); 57 jio_vfprintf(defaultStream::error_stream(), msg, ap); 58 jio_fprintf(defaultStream::error_stream(), "\n"); 59 // Do not change the text of the below message because some tests check for it. 60 vm_exit_during_initialization("Unable to use shared archive.", NULL); 61 } 62 63 64 void FileMapInfo::fail_stop(const char *msg, ...) { 65 va_list ap; 66 va_start(ap, msg); 67 fail(msg, ap); // Never returns. 68 va_end(ap); // for completeness. 69 } 70 71 72 // Complain and continue. Recoverable errors during the reading of the 73 // archive file may continue (with sharing disabled). 74 // 75 // If we continue, then disable shared spaces and close the file. 76 77 void FileMapInfo::fail_continue(const char *msg, ...) { 78 va_list ap; 79 va_start(ap, msg); 80 if (RequireSharedSpaces) { 81 fail(msg, ap); 82 } else { 83 if (PrintSharedSpaces) { 84 tty->print_cr("UseSharedSpaces: %s", msg); 85 } 86 } 87 va_end(ap); 88 UseSharedSpaces = false; 89 close(); 90 } 91 92 // Fill in the fileMapInfo structure with data about this VM instance. 93 94 // This method copies the vm version info into header_version. If the version is too 95 // long then a truncated version, which has a hash code appended to it, is copied. 96 // 97 // Using a template enables this method to verify that header_version is an array of 98 // length JVM_IDENT_MAX. This ensures that the code that writes to the CDS file and 99 // the code that reads the CDS file will both use the same size buffer. Hence, will 100 // use identical truncation. This is necessary for matching of truncated versions. 101 template <int N> static void get_header_version(char (&header_version) [N]) { 102 assert(N == JVM_IDENT_MAX, "Bad header_version size"); 103 104 const char *vm_version = VM_Version::internal_vm_info_string(); 105 const int version_len = (int)strlen(vm_version); 106 107 if (version_len < (JVM_IDENT_MAX-1)) { 108 strcpy(header_version, vm_version); 109 110 } else { 111 // Get the hash value. Use a static seed because the hash needs to return the same 112 // value over multiple jvm invocations. 113 unsigned int hash = AltHashing::murmur3_32(8191, (const jbyte*)vm_version, version_len); 114 115 // Truncate the ident, saving room for the 8 hex character hash value. 116 strncpy(header_version, vm_version, JVM_IDENT_MAX-9); 117 118 // Append the hash code as eight hex digits. 119 sprintf(&header_version[JVM_IDENT_MAX-9], "%08x", hash); 120 header_version[JVM_IDENT_MAX-1] = 0; // Null terminate. 121 } 122 } 123 124 void FileMapInfo::populate_header(size_t alignment) { 125 _header._magic = 0xf00baba2; 126 _header._version = _current_version; 127 _header._alignment = alignment; 128 _header._obj_alignment = ObjectAlignmentInBytes; 129 130 // The following fields are for sanity checks for whether this archive 131 // will function correctly with this JVM and the bootclasspath it's 132 // invoked with. 133 134 // JVM version string ... changes on each build. 135 get_header_version(_header._jvm_ident); 136 137 // Build checks on classpath and jar files 138 _header._num_jars = 0; 139 ClassPathEntry *cpe = ClassLoader::classpath_entry(0); 140 for ( ; cpe != NULL; cpe = cpe->next()) { 141 142 if (cpe->is_jar_file()) { 143 if (_header._num_jars >= JVM_SHARED_JARS_MAX) { 144 fail_stop("Too many jar files to share.", NULL); 145 } 146 147 // Jar file - record timestamp and file size. 148 struct stat st; 149 const char *path = cpe->name(); 150 if (os::stat(path, &st) != 0) { 151 // If we can't access a jar file in the boot path, then we can't 152 // make assumptions about where classes get loaded from. 153 fail_stop("Unable to open jar file %s.", path); 154 } 155 _header._jar[_header._num_jars]._timestamp = st.st_mtime; 156 _header._jar[_header._num_jars]._filesize = st.st_size; 157 _header._num_jars++; 158 } else { 159 160 // If directories appear in boot classpath, they must be empty to 161 // avoid having to verify each individual class file. 162 const char* name = ((ClassPathDirEntry*)cpe)->name(); 163 if (!os::dir_is_empty(name)) { 164 fail_stop("Boot classpath directory %s is not empty.", name); 165 } 166 } 167 } 168 } 169 170 171 // Read the FileMapInfo information from the file. 172 173 bool FileMapInfo::init_from_file(int fd) { 174 175 size_t n = read(fd, &_header, sizeof(struct FileMapHeader)); 176 if (n != sizeof(struct FileMapHeader)) { 177 fail_continue("Unable to read the file header."); 178 return false; 179 } 180 if (_header._version != current_version()) { 181 fail_continue("The shared archive file has the wrong version."); 182 return false; 183 } 184 _file_offset = (long)n; 185 return true; 186 } 187 188 189 // Read the FileMapInfo information from the file. 190 bool FileMapInfo::open_for_read() { 191 _full_path = Arguments::GetSharedArchivePath(); 192 int fd = open(_full_path, O_RDONLY | O_BINARY, 0); 193 if (fd < 0) { 194 if (errno == ENOENT) { 195 // Not locating the shared archive is ok. 196 fail_continue("Specified shared archive not found."); 197 } else { 198 fail_continue("Failed to open shared archive file (%s).", 199 strerror(errno)); 200 } 201 return false; 202 } 203 204 _fd = fd; 205 _file_open = true; 206 return true; 207 } 208 209 210 // Write the FileMapInfo information to the file. 211 212 void FileMapInfo::open_for_write() { 213 _full_path = Arguments::GetSharedArchivePath(); 214 if (PrintSharedSpaces) { 215 tty->print_cr("Dumping shared data to file: "); 216 tty->print_cr(" %s", _full_path); 217 } 218 219 #ifdef _WINDOWS // On Windows, need WRITE permission to remove the file. 220 chmod(_full_path, _S_IREAD | _S_IWRITE); 221 #endif 222 223 // Use remove() to delete the existing file because, on Unix, this will 224 // allow processes that have it open continued access to the file. 225 remove(_full_path); 226 int fd = open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0444); 227 if (fd < 0) { 228 fail_stop("Unable to create shared archive file %s.", _full_path); 229 } 230 _fd = fd; 231 _file_offset = 0; 232 _file_open = true; 233 } 234 235 236 // Write the header to the file, seek to the next allocation boundary. 237 238 void FileMapInfo::write_header() { 239 write_bytes_aligned(&_header, sizeof(FileMapHeader)); 240 } 241 242 243 // Dump shared spaces to file. 244 245 void FileMapInfo::write_space(int i, Metaspace* space, bool read_only) { 246 align_file_position(); 247 size_t used = space->used_bytes_slow(Metaspace::NonClassType); 248 size_t capacity = space->capacity_bytes_slow(Metaspace::NonClassType); 249 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 250 write_region(i, (char*)space->bottom(), used, capacity, read_only, false); 251 } 252 253 254 // Dump region to file. 255 256 void FileMapInfo::write_region(int region, char* base, size_t size, 257 size_t capacity, bool read_only, 258 bool allow_exec) { 259 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[region]; 260 261 if (_file_open) { 262 guarantee(si->_file_offset == _file_offset, "file offset mismatch."); 263 if (PrintSharedSpaces) { 264 tty->print_cr("Shared file region %d: 0x%6x bytes, addr " INTPTR_FORMAT 265 " file offset 0x%6x", region, size, base, _file_offset); 266 } 267 } else { 268 si->_file_offset = _file_offset; 269 } 270 si->_base = base; 271 si->_used = size; 272 si->_capacity = capacity; 273 si->_read_only = read_only; 274 si->_allow_exec = allow_exec; 275 write_bytes_aligned(base, (int)size); 276 } 277 278 279 // Dump bytes to file -- at the current file position. 280 281 void FileMapInfo::write_bytes(const void* buffer, int nbytes) { 282 if (_file_open) { 283 int n = ::write(_fd, buffer, nbytes); 284 if (n != nbytes) { 285 // It is dangerous to leave the corrupted shared archive file around, 286 // close and remove the file. See bug 6372906. 287 close(); 288 remove(_full_path); 289 fail_stop("Unable to write to shared archive file.", NULL); 290 } 291 } 292 _file_offset += nbytes; 293 } 294 295 296 // Align file position to an allocation unit boundary. 297 298 void FileMapInfo::align_file_position() { 299 long new_file_offset = align_size_up(_file_offset, os::vm_allocation_granularity()); 300 if (new_file_offset != _file_offset) { 301 _file_offset = new_file_offset; 302 if (_file_open) { 303 // Seek one byte back from the target and write a byte to insure 304 // that the written file is the correct length. 305 _file_offset -= 1; 306 if (lseek(_fd, _file_offset, SEEK_SET) < 0) { 307 fail_stop("Unable to seek.", NULL); 308 } 309 char zero = 0; 310 write_bytes(&zero, 1); 311 } 312 } 313 } 314 315 316 // Dump bytes to file -- at the current file position. 317 318 void FileMapInfo::write_bytes_aligned(const void* buffer, int nbytes) { 319 align_file_position(); 320 write_bytes(buffer, nbytes); 321 align_file_position(); 322 } 323 324 325 // Close the shared archive file. This does NOT unmap mapped regions. 326 327 void FileMapInfo::close() { 328 if (_file_open) { 329 if (::close(_fd) < 0) { 330 fail_stop("Unable to close the shared archive file."); 331 } 332 _file_open = false; 333 _fd = -1; 334 } 335 } 336 337 338 // JVM/TI RedefineClasses() support: 339 // Remap the shared readonly space to shared readwrite, private. 340 bool FileMapInfo::remap_shared_readonly_as_readwrite() { 341 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0]; 342 if (!si->_read_only) { 343 // the space is already readwrite so we are done 344 return true; 345 } 346 size_t used = si->_used; 347 size_t size = align_size_up(used, os::vm_allocation_granularity()); 348 if (!open_for_read()) { 349 return false; 350 } 351 char *base = os::remap_memory(_fd, _full_path, si->_file_offset, 352 si->_base, size, false /* !read_only */, 353 si->_allow_exec); 354 close(); 355 if (base == NULL) { 356 fail_continue("Unable to remap shared readonly space (errno=%d).", errno); 357 return false; 358 } 359 if (base != si->_base) { 360 fail_continue("Unable to remap shared readonly space at required address."); 361 return false; 362 } 363 si->_read_only = false; 364 return true; 365 } 366 367 // Map the whole region at once, assumed to be allocated contiguously. 368 ReservedSpace FileMapInfo::reserve_shared_memory() { 369 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0]; 370 char* requested_addr = si->_base; 371 372 size_t size = FileMapInfo::shared_spaces_size(); 373 374 // Reserve the space first, then map otherwise map will go right over some 375 // other reserved memory (like the code cache). 376 ReservedSpace rs(size, os::vm_allocation_granularity(), false, requested_addr); 377 if (!rs.is_reserved()) { 378 fail_continue(err_msg("Unable to reserve shared space at required address " INTPTR_FORMAT, requested_addr)); 379 return rs; 380 } 381 // the reserved virtual memory is for mapping class data sharing archive 382 MemTracker::record_virtual_memory_type((address)rs.base(), mtClassShared); 383 384 return rs; 385 } 386 387 // Memory map a region in the address space. 388 static const char* shared_region_name[] = { "ReadOnly", "ReadWrite", "MiscData", "MiscCode"}; 389 390 char* FileMapInfo::map_region(int i) { 391 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 392 size_t used = si->_used; 393 size_t alignment = os::vm_allocation_granularity(); 394 size_t size = align_size_up(used, alignment); 395 char *requested_addr = si->_base; 396 397 // map the contents of the CDS archive in this memory 398 char *base = os::map_memory(_fd, _full_path, si->_file_offset, 399 requested_addr, size, si->_read_only, 400 si->_allow_exec); 401 if (base == NULL || base != si->_base) { 402 fail_continue(err_msg("Unable to map %s shared space at required address.", shared_region_name[i])); 403 return NULL; 404 } 405 #ifdef _WINDOWS 406 // This call is Windows-only because the memory_type gets recorded for the other platforms 407 // in method FileMapInfo::reserve_shared_memory(), which is not called on Windows. 408 MemTracker::record_virtual_memory_type((address)base, mtClassShared); 409 #endif 410 return base; 411 } 412 413 414 // Unmap a memory region in the address space. 415 416 void FileMapInfo::unmap_region(int i) { 417 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 418 size_t used = si->_used; 419 size_t size = align_size_up(used, os::vm_allocation_granularity()); 420 if (!os::unmap_memory(si->_base, size)) { 421 fail_stop("Unable to unmap shared space."); 422 } 423 } 424 425 426 void FileMapInfo::assert_mark(bool check) { 427 if (!check) { 428 fail_stop("Mark mismatch while restoring from shared file.", NULL); 429 } 430 } 431 432 433 FileMapInfo* FileMapInfo::_current_info = NULL; 434 435 436 // Open the shared archive file, read and validate the header 437 // information (version, boot classpath, etc.). If initialization 438 // fails, shared spaces are disabled and the file is closed. [See 439 // fail_continue.] 440 bool FileMapInfo::initialize() { 441 assert(UseSharedSpaces, "UseSharedSpaces expected."); 442 443 if (JvmtiExport::can_modify_any_class() || JvmtiExport::can_walk_any_space()) { 444 fail_continue("Tool agent requires sharing to be disabled."); 445 return false; 446 } 447 448 if (!open_for_read()) { 449 return false; 450 } 451 452 init_from_file(_fd); 453 if (!validate()) { 454 return false; 455 } 456 457 SharedReadOnlySize = _header._space[0]._capacity; 458 SharedReadWriteSize = _header._space[1]._capacity; 459 SharedMiscDataSize = _header._space[2]._capacity; 460 SharedMiscCodeSize = _header._space[3]._capacity; 461 return true; 462 } 463 464 465 bool FileMapInfo::validate() { 466 if (_header._version != current_version()) { 467 fail_continue("The shared archive file is the wrong version."); 468 return false; 469 } 470 if (_header._magic != (int)0xf00baba2) { 471 fail_continue("The shared archive file has a bad magic number."); 472 return false; 473 } 474 char header_version[JVM_IDENT_MAX]; 475 get_header_version(header_version); 476 if (strncmp(_header._jvm_ident, header_version, JVM_IDENT_MAX-1) != 0) { 477 fail_continue("The shared archive file was created by a different" 478 " version or build of HotSpot."); 479 return false; 480 } 481 if (_header._obj_alignment != ObjectAlignmentInBytes) { 482 fail_continue("The shared archive file's ObjectAlignmentInBytes of %d" 483 " does not equal the current ObjectAlignmentInBytes of %d.", 484 _header._obj_alignment, ObjectAlignmentInBytes); 485 return false; 486 } 487 488 // Cannot verify interpreter yet, as it can only be created after the GC 489 // heap has been initialized. 490 491 if (_header._num_jars >= JVM_SHARED_JARS_MAX) { 492 fail_continue("Too many jar files to share."); 493 return false; 494 } 495 496 // Build checks on classpath and jar files 497 int num_jars_now = 0; 498 ClassPathEntry *cpe = ClassLoader::classpath_entry(0); 499 for ( ; cpe != NULL; cpe = cpe->next()) { 500 501 if (cpe->is_jar_file()) { 502 if (num_jars_now < _header._num_jars) { 503 504 // Jar file - verify timestamp and file size. 505 struct stat st; 506 const char *path = cpe->name(); 507 if (os::stat(path, &st) != 0) { 508 fail_continue("Unable to open jar file %s.", path); 509 return false; 510 } 511 if (_header._jar[num_jars_now]._timestamp != st.st_mtime || 512 _header._jar[num_jars_now]._filesize != st.st_size) { 513 fail_continue("A jar file is not the one used while building" 514 " the shared archive file."); 515 return false; 516 } 517 } 518 ++num_jars_now; 519 } else { 520 521 // If directories appear in boot classpath, they must be empty to 522 // avoid having to verify each individual class file. 523 const char* name = ((ClassPathDirEntry*)cpe)->name(); 524 if (!os::dir_is_empty(name)) { 525 fail_continue("Boot classpath directory %s is not empty.", name); 526 return false; 527 } 528 } 529 } 530 if (num_jars_now < _header._num_jars) { 531 fail_continue("The number of jar files in the boot classpath is" 532 " less than the number the shared archive was created with."); 533 return false; 534 } 535 536 return true; 537 } 538 539 // The following method is provided to see whether a given pointer 540 // falls in the mapped shared space. 541 // Param: 542 // p, The given pointer 543 // Return: 544 // True if the p is within the mapped shared space, otherwise, false. 545 bool FileMapInfo::is_in_shared_space(const void* p) { 546 for (int i = 0; i < MetaspaceShared::n_regions; i++) { 547 if (p >= _header._space[i]._base && 548 p < _header._space[i]._base + _header._space[i]._used) { 549 return true; 550 } 551 } 552 553 return false; 554 } 555 556 void FileMapInfo::print_shared_spaces() { 557 gclog_or_tty->print_cr("Shared Spaces:"); 558 for (int i = 0; i < MetaspaceShared::n_regions; i++) { 559 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 560 gclog_or_tty->print(" %s " INTPTR_FORMAT "-" INTPTR_FORMAT, 561 shared_region_name[i], 562 si->_base, si->_base + si->_used); 563 } 564 } 565 566 // Unmap mapped regions of shared space. 567 void FileMapInfo::stop_sharing_and_unmap(const char* msg) { 568 FileMapInfo *map_info = FileMapInfo::current_info(); 569 if (map_info) { 570 map_info->fail_continue(msg); 571 for (int i = 0; i < MetaspaceShared::n_regions; i++) { 572 if (map_info->_header._space[i]._base != NULL) { 573 map_info->unmap_region(i); 574 map_info->_header._space[i]._base = NULL; 575 } 576 } 577 } else if (DumpSharedSpaces) { 578 fail_stop(msg, NULL); 579 } 580 }