filemap.cpp revision 3758:716c64bda5ba
1/* 2 * Copyright (c) 2003, 2012, 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 "memory/filemap.hpp" 29#include "runtime/arguments.hpp" 30#include "runtime/java.hpp" 31#include "runtime/os.hpp" 32#include "services/memTracker.hpp" 33#include "utilities/defaultStream.hpp" 34 35# include <sys/stat.h> 36# include <errno.h> 37 38#ifndef O_BINARY // if defined (Win32) use binary files. 39#define O_BINARY 0 // otherwise do nothing. 40#endif 41 42 43extern address JVM_FunctionAtStart(); 44extern address JVM_FunctionAtEnd(); 45 46// Complain and stop. All error conditions occurring during the writing of 47// an archive file should stop the process. Unrecoverable errors during 48// the reading of the archive file should stop the process. 49 50static void fail(const char *msg, va_list ap) { 51 // This occurs very early during initialization: tty is not initialized. 52 jio_fprintf(defaultStream::error_stream(), 53 "An error has occurred while processing the" 54 " shared archive file.\n"); 55 jio_vfprintf(defaultStream::error_stream(), msg, ap); 56 jio_fprintf(defaultStream::error_stream(), "\n"); 57 vm_exit_during_initialization("Unable to use shared archive.", NULL); 58} 59 60 61void FileMapInfo::fail_stop(const char *msg, ...) { 62 va_list ap; 63 va_start(ap, msg); 64 fail(msg, ap); // Never returns. 65 va_end(ap); // for completeness. 66} 67 68 69// Complain and continue. Recoverable errors during the reading of the 70// archive file may continue (with sharing disabled). 71// 72// If we continue, then disable shared spaces and close the file. 73 74void FileMapInfo::fail_continue(const char *msg, ...) { 75 va_list ap; 76 va_start(ap, msg); 77 if (RequireSharedSpaces) { 78 fail(msg, ap); 79 } 80 va_end(ap); 81 UseSharedSpaces = false; 82 close(); 83} 84 85 86// Fill in the fileMapInfo structure with data about this VM instance. 87 88void FileMapInfo::populate_header(size_t alignment) { 89 _header._magic = 0xf00baba2; 90 _header._version = _current_version; 91 _header._alignment = alignment; 92 93 // The following fields are for sanity checks for whether this archive 94 // will function correctly with this JVM and the bootclasspath it's 95 // invoked with. 96 97 // JVM version string ... changes on each build. 98 const char *vm_version = VM_Version::internal_vm_info_string(); 99 if (strlen(vm_version) < (JVM_IDENT_MAX-1)) { 100 strcpy(_header._jvm_ident, vm_version); 101 } else { 102 fail_stop("JVM Ident field for shared archive is too long" 103 " - truncated to <%s>", _header._jvm_ident); 104 } 105 106 // Build checks on classpath and jar files 107 _header._num_jars = 0; 108 ClassPathEntry *cpe = ClassLoader::classpath_entry(0); 109 for ( ; cpe != NULL; cpe = cpe->next()) { 110 111 if (cpe->is_jar_file()) { 112 if (_header._num_jars >= JVM_SHARED_JARS_MAX) { 113 fail_stop("Too many jar files to share.", NULL); 114 } 115 116 // Jar file - record timestamp and file size. 117 struct stat st; 118 const char *path = cpe->name(); 119 if (os::stat(path, &st) != 0) { 120 // If we can't access a jar file in the boot path, then we can't 121 // make assumptions about where classes get loaded from. 122 fail_stop("Unable to open jar file %s.", path); 123 } 124 _header._jar[_header._num_jars]._timestamp = st.st_mtime; 125 _header._jar[_header._num_jars]._filesize = st.st_size; 126 _header._num_jars++; 127 } else { 128 129 // If directories appear in boot classpath, they must be empty to 130 // avoid having to verify each individual class file. 131 const char* name = ((ClassPathDirEntry*)cpe)->name(); 132 if (!os::dir_is_empty(name)) { 133 fail_stop("Boot classpath directory %s is not empty.", name); 134 } 135 } 136 } 137} 138 139 140// Read the FileMapInfo information from the file. 141 142bool FileMapInfo::init_from_file(int fd) { 143 144 size_t n = read(fd, &_header, sizeof(struct FileMapHeader)); 145 if (n != sizeof(struct FileMapHeader)) { 146 fail_continue("Unable to read the file header."); 147 return false; 148 } 149 if (_header._version != current_version()) { 150 fail_continue("The shared archive file has the wrong version."); 151 return false; 152 } 153 _file_offset = (long)n; 154 return true; 155} 156 157 158// Read the FileMapInfo information from the file. 159bool FileMapInfo::open_for_read() { 160 _full_path = Arguments::GetSharedArchivePath(); 161 int fd = open(_full_path, O_RDONLY | O_BINARY, 0); 162 if (fd < 0) { 163 if (errno == ENOENT) { 164 // Not locating the shared archive is ok. 165 fail_continue("Specified shared archive not found."); 166 } else { 167 fail_continue("Failed to open shared archive file (%s).", 168 strerror(errno)); 169 } 170 return false; 171 } 172 173 _fd = fd; 174 _file_open = true; 175 return true; 176} 177 178 179// Write the FileMapInfo information to the file. 180 181void FileMapInfo::open_for_write() { 182 _full_path = Arguments::GetSharedArchivePath(); 183 if (PrintSharedSpaces) { 184 tty->print_cr("Dumping shared data to file: "); 185 tty->print_cr(" %s", _full_path); 186 } 187 188 // Remove the existing file in case another process has it open. 189 remove(_full_path); 190 int fd = open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0444); 191 if (fd < 0) { 192 fail_stop("Unable to create shared archive file %s.", _full_path); 193 } 194 _fd = fd; 195 _file_offset = 0; 196 _file_open = true; 197} 198 199 200// Write the header to the file, seek to the next allocation boundary. 201 202void FileMapInfo::write_header() { 203 write_bytes_aligned(&_header, sizeof(FileMapHeader)); 204} 205 206 207// Dump shared spaces to file. 208 209void FileMapInfo::write_space(int i, Metaspace* space, bool read_only) { 210 align_file_position(); 211 size_t used = space->used_words(Metaspace::NonClassType) * BytesPerWord; 212 size_t capacity = space->capacity_words(Metaspace::NonClassType) * BytesPerWord; 213 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 214 write_region(i, (char*)space->bottom(), used, capacity, read_only, false); 215} 216 217 218// Dump region to file. 219 220void FileMapInfo::write_region(int region, char* base, size_t size, 221 size_t capacity, bool read_only, 222 bool allow_exec) { 223 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[region]; 224 225 if (_file_open) { 226 guarantee(si->_file_offset == _file_offset, "file offset mismatch."); 227 if (PrintSharedSpaces) { 228 tty->print_cr("Shared file region %d: 0x%6x bytes, addr " INTPTR_FORMAT 229 " file offset 0x%6x", region, size, base, _file_offset); 230 } 231 } else { 232 si->_file_offset = _file_offset; 233 } 234 si->_base = base; 235 si->_used = size; 236 si->_capacity = capacity; 237 si->_read_only = read_only; 238 si->_allow_exec = allow_exec; 239 write_bytes_aligned(base, (int)size); 240} 241 242 243// Dump bytes to file -- at the current file position. 244 245void FileMapInfo::write_bytes(const void* buffer, int nbytes) { 246 if (_file_open) { 247 int n = ::write(_fd, buffer, nbytes); 248 if (n != nbytes) { 249 // It is dangerous to leave the corrupted shared archive file around, 250 // close and remove the file. See bug 6372906. 251 close(); 252 remove(_full_path); 253 fail_stop("Unable to write to shared archive file.", NULL); 254 } 255 } 256 _file_offset += nbytes; 257} 258 259 260// Align file position to an allocation unit boundary. 261 262void FileMapInfo::align_file_position() { 263 long new_file_offset = align_size_up(_file_offset, os::vm_allocation_granularity()); 264 if (new_file_offset != _file_offset) { 265 _file_offset = new_file_offset; 266 if (_file_open) { 267 // Seek one byte back from the target and write a byte to insure 268 // that the written file is the correct length. 269 _file_offset -= 1; 270 if (lseek(_fd, _file_offset, SEEK_SET) < 0) { 271 fail_stop("Unable to seek.", NULL); 272 } 273 char zero = 0; 274 write_bytes(&zero, 1); 275 } 276 } 277} 278 279 280// Dump bytes to file -- at the current file position. 281 282void FileMapInfo::write_bytes_aligned(const void* buffer, int nbytes) { 283 align_file_position(); 284 write_bytes(buffer, nbytes); 285 align_file_position(); 286} 287 288 289// Close the shared archive file. This does NOT unmap mapped regions. 290 291void FileMapInfo::close() { 292 if (_file_open) { 293 if (::close(_fd) < 0) { 294 fail_stop("Unable to close the shared archive file."); 295 } 296 _file_open = false; 297 _fd = -1; 298 } 299} 300 301 302// JVM/TI RedefineClasses() support: 303// Remap the shared readonly space to shared readwrite, private. 304bool FileMapInfo::remap_shared_readonly_as_readwrite() { 305 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0]; 306 if (!si->_read_only) { 307 // the space is already readwrite so we are done 308 return true; 309 } 310 size_t used = si->_used; 311 size_t size = align_size_up(used, os::vm_allocation_granularity()); 312 if (!open_for_read()) { 313 return false; 314 } 315 char *base = os::remap_memory(_fd, _full_path, si->_file_offset, 316 si->_base, size, false /* !read_only */, 317 si->_allow_exec); 318 close(); 319 if (base == NULL) { 320 fail_continue("Unable to remap shared readonly space (errno=%d).", errno); 321 return false; 322 } 323 if (base != si->_base) { 324 fail_continue("Unable to remap shared readonly space at required address."); 325 return false; 326 } 327 si->_read_only = false; 328 return true; 329} 330 331// Map the whole region at once, assumed to be allocated contiguously. 332ReservedSpace FileMapInfo::reserve_shared_memory() { 333 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0]; 334 char* requested_addr = si->_base; 335 size_t alignment = os::vm_allocation_granularity(); 336 337 size_t size = align_size_up(SharedReadOnlySize + SharedReadWriteSize + 338 SharedMiscDataSize + SharedMiscCodeSize, 339 alignment); 340 341 // Reserve the space first, then map otherwise map will go right over some 342 // other reserved memory (like the code cache). 343 ReservedSpace rs(size, alignment, false, requested_addr); 344 if (!rs.is_reserved()) { 345 fail_continue(err_msg("Unable to reserved shared space at required address " INTPTR_FORMAT, requested_addr)); 346 return rs; 347 } 348 // the reserved virtual memory is for mapping class data sharing archive 349 if (MemTracker::is_on()) { 350 MemTracker::record_virtual_memory_type((address)rs.base(), mtClassShared); 351 } 352 return rs; 353} 354 355// Memory map a region in the address space. 356static const char* shared_region_name[] = { "ReadOnly", "ReadWrite", "MiscData", "MiscCode"}; 357 358char* FileMapInfo::map_region(int i) { 359 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 360 size_t used = si->_used; 361 size_t alignment = os::vm_allocation_granularity(); 362 size_t size = align_size_up(used, alignment); 363 char *requested_addr = si->_base; 364 365 // map the contents of the CDS archive in this memory 366 char *base = os::map_memory(_fd, _full_path, si->_file_offset, 367 requested_addr, size, si->_read_only, 368 si->_allow_exec); 369 if (base == NULL || base != si->_base) { 370 fail_continue(err_msg("Unable to map %s shared space at required address.", shared_region_name[i])); 371 return NULL; 372 } 373 return base; 374} 375 376 377// Unmap a memory region in the address space. 378 379void FileMapInfo::unmap_region(int i) { 380 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 381 size_t used = si->_used; 382 size_t size = align_size_up(used, os::vm_allocation_granularity()); 383 if (!os::unmap_memory(si->_base, size)) { 384 fail_stop("Unable to unmap shared space."); 385 } 386} 387 388 389void FileMapInfo::assert_mark(bool check) { 390 if (!check) { 391 fail_stop("Mark mismatch while restoring from shared file.", NULL); 392 } 393} 394 395 396FileMapInfo* FileMapInfo::_current_info = NULL; 397 398 399// Open the shared archive file, read and validate the header 400// information (version, boot classpath, etc.). If initialization 401// fails, shared spaces are disabled and the file is closed. [See 402// fail_continue.] 403bool FileMapInfo::initialize() { 404 assert(UseSharedSpaces, "UseSharedSpaces expected."); 405 406 if (JvmtiExport::can_modify_any_class() || JvmtiExport::can_walk_any_space()) { 407 fail_continue("Tool agent requires sharing to be disabled."); 408 return false; 409 } 410 411 if (!open_for_read()) { 412 return false; 413 } 414 415 init_from_file(_fd); 416 if (!validate()) { 417 return false; 418 } 419 420 SharedReadOnlySize = _header._space[0]._capacity; 421 SharedReadWriteSize = _header._space[1]._capacity; 422 SharedMiscDataSize = _header._space[2]._capacity; 423 SharedMiscCodeSize = _header._space[3]._capacity; 424 return true; 425} 426 427 428bool FileMapInfo::validate() { 429 if (_header._version != current_version()) { 430 fail_continue("The shared archive file is the wrong version."); 431 return false; 432 } 433 if (_header._magic != (int)0xf00baba2) { 434 fail_continue("The shared archive file has a bad magic number."); 435 return false; 436 } 437 if (strncmp(_header._jvm_ident, VM_Version::internal_vm_info_string(), 438 JVM_IDENT_MAX-1) != 0) { 439 fail_continue("The shared archive file was created by a different" 440 " version or build of HotSpot."); 441 return false; 442 } 443 444 // Cannot verify interpreter yet, as it can only be created after the GC 445 // heap has been initialized. 446 447 if (_header._num_jars >= JVM_SHARED_JARS_MAX) { 448 fail_continue("Too many jar files to share."); 449 return false; 450 } 451 452 // Build checks on classpath and jar files 453 int num_jars_now = 0; 454 ClassPathEntry *cpe = ClassLoader::classpath_entry(0); 455 for ( ; cpe != NULL; cpe = cpe->next()) { 456 457 if (cpe->is_jar_file()) { 458 if (num_jars_now < _header._num_jars) { 459 460 // Jar file - verify timestamp and file size. 461 struct stat st; 462 const char *path = cpe->name(); 463 if (os::stat(path, &st) != 0) { 464 fail_continue("Unable to open jar file %s.", path); 465 return false; 466 } 467 if (_header._jar[num_jars_now]._timestamp != st.st_mtime || 468 _header._jar[num_jars_now]._filesize != st.st_size) { 469 fail_continue("A jar file is not the one used while building" 470 " the shared archive file."); 471 return false; 472 } 473 } 474 ++num_jars_now; 475 } else { 476 477 // If directories appear in boot classpath, they must be empty to 478 // avoid having to verify each individual class file. 479 const char* name = ((ClassPathDirEntry*)cpe)->name(); 480 if (!os::dir_is_empty(name)) { 481 fail_continue("Boot classpath directory %s is not empty.", name); 482 return false; 483 } 484 } 485 } 486 if (num_jars_now < _header._num_jars) { 487 fail_continue("The number of jar files in the boot classpath is" 488 " less than the number the shared archive was created with."); 489 return false; 490 } 491 492 return true; 493} 494 495// The following method is provided to see whether a given pointer 496// falls in the mapped shared space. 497// Param: 498// p, The given pointer 499// Return: 500// True if the p is within the mapped shared space, otherwise, false. 501bool FileMapInfo::is_in_shared_space(const void* p) { 502 for (int i = 0; i < MetaspaceShared::n_regions; i++) { 503 if (p >= _header._space[i]._base && 504 p < _header._space[i]._base + _header._space[i]._used) { 505 return true; 506 } 507 } 508 509 return false; 510} 511