filemap.cpp revision 4369:91bf0bdae37b
1/* 2 * Copyright (c) 2003, 2013, 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 44extern address JVM_FunctionAtStart(); 45extern address JVM_FunctionAtEnd(); 46 47// Complain and stop. All error conditions occurring during the writing of 48// an archive file should stop the process. Unrecoverable errors during 49// the reading of the archive file should stop the process. 50 51static void fail(const char *msg, va_list ap) { 52 // This occurs very early during initialization: tty is not initialized. 53 jio_fprintf(defaultStream::error_stream(), 54 "An error has occurred while processing the" 55 " shared archive file.\n"); 56 jio_vfprintf(defaultStream::error_stream(), msg, ap); 57 jio_fprintf(defaultStream::error_stream(), "\n"); 58 vm_exit_during_initialization("Unable to use shared archive.", NULL); 59} 60 61 62void FileMapInfo::fail_stop(const char *msg, ...) { 63 va_list ap; 64 va_start(ap, msg); 65 fail(msg, ap); // Never returns. 66 va_end(ap); // for completeness. 67} 68 69 70// Complain and continue. Recoverable errors during the reading of the 71// archive file may continue (with sharing disabled). 72// 73// If we continue, then disable shared spaces and close the file. 74 75void FileMapInfo::fail_continue(const char *msg, ...) { 76 va_list ap; 77 va_start(ap, msg); 78 if (RequireSharedSpaces) { 79 fail(msg, ap); 80 } 81 va_end(ap); 82 UseSharedSpaces = false; 83 close(); 84} 85 86// Fill in the fileMapInfo structure with data about this VM instance. 87 88// This method copies the vm version info into header_version. If the version is too 89// long then a truncated version, which has a hash code appended to it, is copied. 90// 91// Using a template enables this method to verify that header_version is an array of 92// length JVM_IDENT_MAX. This ensures that the code that writes to the CDS file and 93// the code that reads the CDS file will both use the same size buffer. Hence, will 94// use identical truncation. This is necessary for matching of truncated versions. 95template <int N> static void get_header_version(char (&header_version) [N]) { 96 assert(N == JVM_IDENT_MAX, "Bad header_version size"); 97 98 const char *vm_version = VM_Version::internal_vm_info_string(); 99 const int version_len = (int)strlen(vm_version); 100 101 if (version_len < (JVM_IDENT_MAX-1)) { 102 strcpy(header_version, vm_version); 103 104 } else { 105 // Get the hash value. Use a static seed because the hash needs to return the same 106 // value over multiple jvm invocations. 107 unsigned int hash = AltHashing::murmur3_32(8191, (const jbyte*)vm_version, version_len); 108 109 // Truncate the ident, saving room for the 8 hex character hash value. 110 strncpy(header_version, vm_version, JVM_IDENT_MAX-9); 111 112 // Append the hash code as eight hex digits. 113 sprintf(&header_version[JVM_IDENT_MAX-9], "%08x", hash); 114 header_version[JVM_IDENT_MAX-1] = 0; // Null terminate. 115 } 116} 117 118void FileMapInfo::populate_header(size_t alignment) { 119 _header._magic = 0xf00baba2; 120 _header._version = _current_version; 121 _header._alignment = alignment; 122 _header._obj_alignment = ObjectAlignmentInBytes; 123 124 // The following fields are for sanity checks for whether this archive 125 // will function correctly with this JVM and the bootclasspath it's 126 // invoked with. 127 128 // JVM version string ... changes on each build. 129 get_header_version(_header._jvm_ident); 130 131 // Build checks on classpath and jar files 132 _header._num_jars = 0; 133 ClassPathEntry *cpe = ClassLoader::classpath_entry(0); 134 for ( ; cpe != NULL; cpe = cpe->next()) { 135 136 if (cpe->is_jar_file()) { 137 if (_header._num_jars >= JVM_SHARED_JARS_MAX) { 138 fail_stop("Too many jar files to share.", NULL); 139 } 140 141 // Jar file - record timestamp and file size. 142 struct stat st; 143 const char *path = cpe->name(); 144 if (os::stat(path, &st) != 0) { 145 // If we can't access a jar file in the boot path, then we can't 146 // make assumptions about where classes get loaded from. 147 fail_stop("Unable to open jar file %s.", path); 148 } 149 _header._jar[_header._num_jars]._timestamp = st.st_mtime; 150 _header._jar[_header._num_jars]._filesize = st.st_size; 151 _header._num_jars++; 152 } else { 153 154 // If directories appear in boot classpath, they must be empty to 155 // avoid having to verify each individual class file. 156 const char* name = ((ClassPathDirEntry*)cpe)->name(); 157 if (!os::dir_is_empty(name)) { 158 fail_stop("Boot classpath directory %s is not empty.", name); 159 } 160 } 161 } 162} 163 164 165// Read the FileMapInfo information from the file. 166 167bool FileMapInfo::init_from_file(int fd) { 168 169 size_t n = read(fd, &_header, sizeof(struct FileMapHeader)); 170 if (n != sizeof(struct FileMapHeader)) { 171 fail_continue("Unable to read the file header."); 172 return false; 173 } 174 if (_header._version != current_version()) { 175 fail_continue("The shared archive file has the wrong version."); 176 return false; 177 } 178 _file_offset = (long)n; 179 return true; 180} 181 182 183// Read the FileMapInfo information from the file. 184bool FileMapInfo::open_for_read() { 185 _full_path = Arguments::GetSharedArchivePath(); 186 int fd = open(_full_path, O_RDONLY | O_BINARY, 0); 187 if (fd < 0) { 188 if (errno == ENOENT) { 189 // Not locating the shared archive is ok. 190 fail_continue("Specified shared archive not found."); 191 } else { 192 fail_continue("Failed to open shared archive file (%s).", 193 strerror(errno)); 194 } 195 return false; 196 } 197 198 _fd = fd; 199 _file_open = true; 200 return true; 201} 202 203 204// Write the FileMapInfo information to the file. 205 206void FileMapInfo::open_for_write() { 207 _full_path = Arguments::GetSharedArchivePath(); 208 if (PrintSharedSpaces) { 209 tty->print_cr("Dumping shared data to file: "); 210 tty->print_cr(" %s", _full_path); 211 } 212 213#ifdef _WINDOWS // On Windows, need WRITE permission to remove the file. 214 chmod(_full_path, _S_IREAD | _S_IWRITE); 215#endif 216 217 // Use remove() to delete the existing file because, on Unix, this will 218 // allow processes that have it open continued access to the file. 219 remove(_full_path); 220 int fd = open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0444); 221 if (fd < 0) { 222 fail_stop("Unable to create shared archive file %s.", _full_path); 223 } 224 _fd = fd; 225 _file_offset = 0; 226 _file_open = true; 227} 228 229 230// Write the header to the file, seek to the next allocation boundary. 231 232void FileMapInfo::write_header() { 233 write_bytes_aligned(&_header, sizeof(FileMapHeader)); 234} 235 236 237// Dump shared spaces to file. 238 239void FileMapInfo::write_space(int i, Metaspace* space, bool read_only) { 240 align_file_position(); 241 size_t used = space->used_words(Metaspace::NonClassType) * BytesPerWord; 242 size_t capacity = space->capacity_words(Metaspace::NonClassType) * BytesPerWord; 243 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 244 write_region(i, (char*)space->bottom(), used, capacity, read_only, false); 245} 246 247 248// Dump region to file. 249 250void FileMapInfo::write_region(int region, char* base, size_t size, 251 size_t capacity, bool read_only, 252 bool allow_exec) { 253 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[region]; 254 255 if (_file_open) { 256 guarantee(si->_file_offset == _file_offset, "file offset mismatch."); 257 if (PrintSharedSpaces) { 258 tty->print_cr("Shared file region %d: 0x%6x bytes, addr " INTPTR_FORMAT 259 " file offset 0x%6x", region, size, base, _file_offset); 260 } 261 } else { 262 si->_file_offset = _file_offset; 263 } 264 si->_base = base; 265 si->_used = size; 266 si->_capacity = capacity; 267 si->_read_only = read_only; 268 si->_allow_exec = allow_exec; 269 write_bytes_aligned(base, (int)size); 270} 271 272 273// Dump bytes to file -- at the current file position. 274 275void FileMapInfo::write_bytes(const void* buffer, int nbytes) { 276 if (_file_open) { 277 int n = ::write(_fd, buffer, nbytes); 278 if (n != nbytes) { 279 // It is dangerous to leave the corrupted shared archive file around, 280 // close and remove the file. See bug 6372906. 281 close(); 282 remove(_full_path); 283 fail_stop("Unable to write to shared archive file.", NULL); 284 } 285 } 286 _file_offset += nbytes; 287} 288 289 290// Align file position to an allocation unit boundary. 291 292void FileMapInfo::align_file_position() { 293 long new_file_offset = align_size_up(_file_offset, os::vm_allocation_granularity()); 294 if (new_file_offset != _file_offset) { 295 _file_offset = new_file_offset; 296 if (_file_open) { 297 // Seek one byte back from the target and write a byte to insure 298 // that the written file is the correct length. 299 _file_offset -= 1; 300 if (lseek(_fd, _file_offset, SEEK_SET) < 0) { 301 fail_stop("Unable to seek.", NULL); 302 } 303 char zero = 0; 304 write_bytes(&zero, 1); 305 } 306 } 307} 308 309 310// Dump bytes to file -- at the current file position. 311 312void FileMapInfo::write_bytes_aligned(const void* buffer, int nbytes) { 313 align_file_position(); 314 write_bytes(buffer, nbytes); 315 align_file_position(); 316} 317 318 319// Close the shared archive file. This does NOT unmap mapped regions. 320 321void FileMapInfo::close() { 322 if (_file_open) { 323 if (::close(_fd) < 0) { 324 fail_stop("Unable to close the shared archive file."); 325 } 326 _file_open = false; 327 _fd = -1; 328 } 329} 330 331 332// JVM/TI RedefineClasses() support: 333// Remap the shared readonly space to shared readwrite, private. 334bool FileMapInfo::remap_shared_readonly_as_readwrite() { 335 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0]; 336 if (!si->_read_only) { 337 // the space is already readwrite so we are done 338 return true; 339 } 340 size_t used = si->_used; 341 size_t size = align_size_up(used, os::vm_allocation_granularity()); 342 if (!open_for_read()) { 343 return false; 344 } 345 char *base = os::remap_memory(_fd, _full_path, si->_file_offset, 346 si->_base, size, false /* !read_only */, 347 si->_allow_exec); 348 close(); 349 if (base == NULL) { 350 fail_continue("Unable to remap shared readonly space (errno=%d).", errno); 351 return false; 352 } 353 if (base != si->_base) { 354 fail_continue("Unable to remap shared readonly space at required address."); 355 return false; 356 } 357 si->_read_only = false; 358 return true; 359} 360 361// Map the whole region at once, assumed to be allocated contiguously. 362ReservedSpace FileMapInfo::reserve_shared_memory() { 363 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0]; 364 char* requested_addr = si->_base; 365 size_t alignment = os::vm_allocation_granularity(); 366 367 size_t size = align_size_up(SharedReadOnlySize + SharedReadWriteSize + 368 SharedMiscDataSize + SharedMiscCodeSize, 369 alignment); 370 371 // Reserve the space first, then map otherwise map will go right over some 372 // other reserved memory (like the code cache). 373 ReservedSpace rs(size, alignment, false, requested_addr); 374 if (!rs.is_reserved()) { 375 fail_continue(err_msg("Unable to reserve shared space at required address " INTPTR_FORMAT, requested_addr)); 376 return rs; 377 } 378 // the reserved virtual memory is for mapping class data sharing archive 379 MemTracker::record_virtual_memory_type((address)rs.base(), mtClassShared); 380 381 return rs; 382} 383 384// Memory map a region in the address space. 385static const char* shared_region_name[] = { "ReadOnly", "ReadWrite", "MiscData", "MiscCode"}; 386 387char* FileMapInfo::map_region(int i) { 388 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 389 size_t used = si->_used; 390 size_t alignment = os::vm_allocation_granularity(); 391 size_t size = align_size_up(used, alignment); 392 char *requested_addr = si->_base; 393 394 // map the contents of the CDS archive in this memory 395 char *base = os::map_memory(_fd, _full_path, si->_file_offset, 396 requested_addr, size, si->_read_only, 397 si->_allow_exec); 398 if (base == NULL || base != si->_base) { 399 fail_continue(err_msg("Unable to map %s shared space at required address.", shared_region_name[i])); 400 return NULL; 401 } 402#ifdef _WINDOWS 403 // This call is Windows-only because the memory_type gets recorded for the other platforms 404 // in method FileMapInfo::reserve_shared_memory(), which is not called on Windows. 405 MemTracker::record_virtual_memory_type((address)base, mtClassShared); 406#endif 407 return base; 408} 409 410 411// Unmap a memory region in the address space. 412 413void FileMapInfo::unmap_region(int i) { 414 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 415 size_t used = si->_used; 416 size_t size = align_size_up(used, os::vm_allocation_granularity()); 417 if (!os::unmap_memory(si->_base, size)) { 418 fail_stop("Unable to unmap shared space."); 419 } 420} 421 422 423void FileMapInfo::assert_mark(bool check) { 424 if (!check) { 425 fail_stop("Mark mismatch while restoring from shared file.", NULL); 426 } 427} 428 429 430FileMapInfo* FileMapInfo::_current_info = NULL; 431 432 433// Open the shared archive file, read and validate the header 434// information (version, boot classpath, etc.). If initialization 435// fails, shared spaces are disabled and the file is closed. [See 436// fail_continue.] 437bool FileMapInfo::initialize() { 438 assert(UseSharedSpaces, "UseSharedSpaces expected."); 439 440 if (JvmtiExport::can_modify_any_class() || JvmtiExport::can_walk_any_space()) { 441 fail_continue("Tool agent requires sharing to be disabled."); 442 return false; 443 } 444 445 if (!open_for_read()) { 446 return false; 447 } 448 449 init_from_file(_fd); 450 if (!validate()) { 451 return false; 452 } 453 454 SharedReadOnlySize = _header._space[0]._capacity; 455 SharedReadWriteSize = _header._space[1]._capacity; 456 SharedMiscDataSize = _header._space[2]._capacity; 457 SharedMiscCodeSize = _header._space[3]._capacity; 458 return true; 459} 460 461 462bool FileMapInfo::validate() { 463 if (_header._version != current_version()) { 464 fail_continue("The shared archive file is the wrong version."); 465 return false; 466 } 467 if (_header._magic != (int)0xf00baba2) { 468 fail_continue("The shared archive file has a bad magic number."); 469 return false; 470 } 471 char header_version[JVM_IDENT_MAX]; 472 get_header_version(header_version); 473 if (strncmp(_header._jvm_ident, header_version, JVM_IDENT_MAX-1) != 0) { 474 fail_continue("The shared archive file was created by a different" 475 " version or build of HotSpot."); 476 return false; 477 } 478 if (_header._obj_alignment != ObjectAlignmentInBytes) { 479 fail_continue("The shared archive file's ObjectAlignmentInBytes of %d" 480 " does not equal the current ObjectAlignmentInBytes of %d.", 481 _header._obj_alignment, ObjectAlignmentInBytes); 482 return false; 483 } 484 485 // Cannot verify interpreter yet, as it can only be created after the GC 486 // heap has been initialized. 487 488 if (_header._num_jars >= JVM_SHARED_JARS_MAX) { 489 fail_continue("Too many jar files to share."); 490 return false; 491 } 492 493 // Build checks on classpath and jar files 494 int num_jars_now = 0; 495 ClassPathEntry *cpe = ClassLoader::classpath_entry(0); 496 for ( ; cpe != NULL; cpe = cpe->next()) { 497 498 if (cpe->is_jar_file()) { 499 if (num_jars_now < _header._num_jars) { 500 501 // Jar file - verify timestamp and file size. 502 struct stat st; 503 const char *path = cpe->name(); 504 if (os::stat(path, &st) != 0) { 505 fail_continue("Unable to open jar file %s.", path); 506 return false; 507 } 508 if (_header._jar[num_jars_now]._timestamp != st.st_mtime || 509 _header._jar[num_jars_now]._filesize != st.st_size) { 510 fail_continue("A jar file is not the one used while building" 511 " the shared archive file."); 512 return false; 513 } 514 } 515 ++num_jars_now; 516 } else { 517 518 // If directories appear in boot classpath, they must be empty to 519 // avoid having to verify each individual class file. 520 const char* name = ((ClassPathDirEntry*)cpe)->name(); 521 if (!os::dir_is_empty(name)) { 522 fail_continue("Boot classpath directory %s is not empty.", name); 523 return false; 524 } 525 } 526 } 527 if (num_jars_now < _header._num_jars) { 528 fail_continue("The number of jar files in the boot classpath is" 529 " less than the number the shared archive was created with."); 530 return false; 531 } 532 533 return true; 534} 535 536// The following method is provided to see whether a given pointer 537// falls in the mapped shared space. 538// Param: 539// p, The given pointer 540// Return: 541// True if the p is within the mapped shared space, otherwise, false. 542bool FileMapInfo::is_in_shared_space(const void* p) { 543 for (int i = 0; i < MetaspaceShared::n_regions; i++) { 544 if (p >= _header._space[i]._base && 545 p < _header._space[i]._base + _header._space[i]._used) { 546 return true; 547 } 548 } 549 550 return false; 551} 552