filemap.cpp revision 1472:c18cbe5936b8
1/* 2 * Copyright (c) 2003, 2006, 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 "incls/_precompiled.incl" 26# include "incls/_filemap.cpp.incl" 27# include <sys/stat.h> 28# include <errno.h> 29 30#ifndef O_BINARY // if defined (Win32) use binary files. 31#define O_BINARY 0 // otherwise do nothing. 32#endif 33 34 35extern address JVM_FunctionAtStart(); 36extern address JVM_FunctionAtEnd(); 37 38// Complain and stop. All error conditions occurring during the writing of 39// an archive file should stop the process. Unrecoverable errors during 40// the reading of the archive file should stop the process. 41 42static void fail(const char *msg, va_list ap) { 43 // This occurs very early during initialization: tty is not initialized. 44 jio_fprintf(defaultStream::error_stream(), 45 "An error has occurred while processing the" 46 " shared archive file.\n"); 47 jio_vfprintf(defaultStream::error_stream(), msg, ap); 48 jio_fprintf(defaultStream::error_stream(), "\n"); 49 vm_exit_during_initialization("Unable to use shared archive.", NULL); 50} 51 52 53void FileMapInfo::fail_stop(const char *msg, ...) { 54 va_list ap; 55 va_start(ap, msg); 56 fail(msg, ap); // Never returns. 57 va_end(ap); // for completeness. 58} 59 60 61// Complain and continue. Recoverable errors during the reading of the 62// archive file may continue (with sharing disabled). 63// 64// If we continue, then disable shared spaces and close the file. 65 66void FileMapInfo::fail_continue(const char *msg, ...) { 67 va_list ap; 68 va_start(ap, msg); 69 if (RequireSharedSpaces) { 70 fail(msg, ap); 71 } 72 va_end(ap); 73 UseSharedSpaces = false; 74 close(); 75} 76 77 78// Fill in the fileMapInfo structure with data about this VM instance. 79 80void FileMapInfo::populate_header(size_t alignment) { 81 _header._magic = 0xf00baba2; 82 _header._version = _current_version; 83 _header._alignment = alignment; 84 85 // The following fields are for sanity checks for whether this archive 86 // will function correctly with this JVM and the bootclasspath it's 87 // invoked with. 88 89 // JVM version string ... changes on each build. 90 const char *vm_version = VM_Version::internal_vm_info_string(); 91 if (strlen(vm_version) < (JVM_IDENT_MAX-1)) { 92 strcpy(_header._jvm_ident, vm_version); 93 } else { 94 fail_stop("JVM Ident field for shared archive is too long" 95 " - truncated to <%s>", _header._jvm_ident); 96 } 97 98 // Build checks on classpath and jar files 99 _header._num_jars = 0; 100 ClassPathEntry *cpe = ClassLoader::classpath_entry(0); 101 for ( ; cpe != NULL; cpe = cpe->next()) { 102 103 if (cpe->is_jar_file()) { 104 if (_header._num_jars >= JVM_SHARED_JARS_MAX) { 105 fail_stop("Too many jar files to share.", NULL); 106 } 107 108 // Jar file - record timestamp and file size. 109 struct stat st; 110 const char *path = cpe->name(); 111 if (os::stat(path, &st) != 0) { 112 // If we can't access a jar file in the boot path, then we can't 113 // make assumptions about where classes get loaded from. 114 fail_stop("Unable to open jar file %s.", path); 115 } 116 _header._jar[_header._num_jars]._timestamp = st.st_mtime; 117 _header._jar[_header._num_jars]._filesize = st.st_size; 118 _header._num_jars++; 119 } else { 120 121 // If directories appear in boot classpath, they must be empty to 122 // avoid having to verify each individual class file. 123 const char* name = ((ClassPathDirEntry*)cpe)->name(); 124 if (!os::dir_is_empty(name)) { 125 fail_stop("Boot classpath directory %s is not empty.", name); 126 } 127 } 128 } 129} 130 131 132// Read the FileMapInfo information from the file. 133 134bool FileMapInfo::init_from_file(int fd) { 135 136 size_t n = read(fd, &_header, sizeof(struct FileMapHeader)); 137 if (n != sizeof(struct FileMapHeader)) { 138 fail_continue("Unable to read the file header."); 139 return false; 140 } 141 if (_header._version != current_version()) { 142 fail_continue("The shared archive file has the wrong version."); 143 return false; 144 } 145 _file_offset = (long)n; 146 return true; 147} 148 149 150// Read the FileMapInfo information from the file. 151bool FileMapInfo::open_for_read() { 152 _full_path = Arguments::GetSharedArchivePath(); 153 int fd = open(_full_path, O_RDONLY | O_BINARY, 0); 154 if (fd < 0) { 155 if (errno == ENOENT) { 156 // Not locating the shared archive is ok. 157 fail_continue("Specified shared archive not found."); 158 } else { 159 fail_continue("Failed to open shared archive file (%s).", 160 strerror(errno)); 161 } 162 return false; 163 } 164 165 _fd = fd; 166 _file_open = true; 167 return true; 168} 169 170 171// Write the FileMapInfo information to the file. 172 173void FileMapInfo::open_for_write() { 174 _full_path = Arguments::GetSharedArchivePath(); 175 if (PrintSharedSpaces) { 176 tty->print_cr("Dumping shared data to file: "); 177 tty->print_cr(" %s", _full_path); 178 } 179 180 // Remove the existing file in case another process has it open. 181 remove(_full_path); 182 int fd = open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0444); 183 if (fd < 0) { 184 fail_stop("Unable to create shared archive file %s.", _full_path); 185 } 186 _fd = fd; 187 _file_offset = 0; 188 _file_open = true; 189} 190 191 192// Write the header to the file, seek to the next allocation boundary. 193 194void FileMapInfo::write_header() { 195 write_bytes_aligned(&_header, sizeof(FileMapHeader)); 196} 197 198 199// Dump shared spaces to file. 200 201void FileMapInfo::write_space(int i, CompactibleSpace* space, bool read_only) { 202 align_file_position(); 203 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 204 write_region(i, (char*)space->bottom(), space->used(), 205 space->capacity(), read_only, false); 206} 207 208 209// Dump region to file. 210 211void FileMapInfo::write_region(int region, char* base, size_t size, 212 size_t capacity, bool read_only, 213 bool allow_exec) { 214 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[region]; 215 216 if (_file_open) { 217 guarantee(si->_file_offset == _file_offset, "file offset mismatch."); 218 if (PrintSharedSpaces) { 219 tty->print_cr("Shared file region %d: 0x%x bytes, addr 0x%x," 220 " file offset 0x%x", region, size, base, _file_offset); 221 } 222 } else { 223 si->_file_offset = _file_offset; 224 } 225 si->_base = base; 226 si->_used = size; 227 si->_capacity = capacity; 228 si->_read_only = read_only; 229 si->_allow_exec = allow_exec; 230 write_bytes_aligned(base, (int)size); 231} 232 233 234// Dump bytes to file -- at the current file position. 235 236void FileMapInfo::write_bytes(const void* buffer, int nbytes) { 237 if (_file_open) { 238 int n = ::write(_fd, buffer, nbytes); 239 if (n != nbytes) { 240 // It is dangerous to leave the corrupted shared archive file around, 241 // close and remove the file. See bug 6372906. 242 close(); 243 remove(_full_path); 244 fail_stop("Unable to write to shared archive file.", NULL); 245 } 246 } 247 _file_offset += nbytes; 248} 249 250 251// Align file position to an allocation unit boundary. 252 253void FileMapInfo::align_file_position() { 254 long new_file_offset = align_size_up(_file_offset, os::vm_allocation_granularity()); 255 if (new_file_offset != _file_offset) { 256 _file_offset = new_file_offset; 257 if (_file_open) { 258 // Seek one byte back from the target and write a byte to insure 259 // that the written file is the correct length. 260 _file_offset -= 1; 261 if (lseek(_fd, _file_offset, SEEK_SET) < 0) { 262 fail_stop("Unable to seek.", NULL); 263 } 264 char zero = 0; 265 write_bytes(&zero, 1); 266 } 267 } 268} 269 270 271// Dump bytes to file -- at the current file position. 272 273void FileMapInfo::write_bytes_aligned(const void* buffer, int nbytes) { 274 align_file_position(); 275 write_bytes(buffer, nbytes); 276 align_file_position(); 277} 278 279 280// Close the shared archive file. This does NOT unmap mapped regions. 281 282void FileMapInfo::close() { 283 if (_file_open) { 284 if (::close(_fd) < 0) { 285 fail_stop("Unable to close the shared archive file."); 286 } 287 _file_open = false; 288 _fd = -1; 289 } 290} 291 292 293// Memory map a shared space from the archive file. 294 295bool FileMapInfo::map_space(int i, ReservedSpace rs, ContiguousSpace* space) { 296 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 297 if (space != NULL) { 298 if (si->_base != (char*)space->bottom() || 299 si->_capacity != space->capacity()) { 300 fail_continue("Shared space base address does not match."); 301 return false; 302 } 303 } 304 bool result = (map_region(i, rs) != NULL); 305 if (space != NULL && result) { 306 space->set_top((HeapWord*)(si->_base + si->_used)); 307 space->set_saved_mark(); 308 } 309 return result; 310} 311 312 313// JVM/TI RedefineClasses() support: 314// Remap the shared readonly space to shared readwrite, private. 315bool FileMapInfo::remap_shared_readonly_as_readwrite() { 316 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0]; 317 if (!si->_read_only) { 318 // the space is already readwrite so we are done 319 return true; 320 } 321 size_t used = si->_used; 322 size_t size = align_size_up(used, os::vm_allocation_granularity()); 323 if (!open_for_read()) { 324 return false; 325 } 326 char *base = os::remap_memory(_fd, _full_path, si->_file_offset, 327 si->_base, size, false /* !read_only */, 328 si->_allow_exec); 329 close(); 330 if (base == NULL) { 331 fail_continue("Unable to remap shared readonly space (errno=%d).", errno); 332 return false; 333 } 334 if (base != si->_base) { 335 fail_continue("Unable to remap shared readonly space at required address."); 336 return false; 337 } 338 si->_read_only = false; 339 return true; 340} 341 342 343// Memory map a region in the address space. 344 345char* FileMapInfo::map_region(int i, ReservedSpace rs) { 346 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 347 size_t used = si->_used; 348 size_t size = align_size_up(used, os::vm_allocation_granularity()); 349 350 ReservedSpace mapped_rs = rs.first_part(size, true, true); 351 ReservedSpace unmapped_rs = rs.last_part(size); 352 mapped_rs.release(); 353 354 return map_region(i, true); 355} 356 357 358// Memory map a region in the address space. 359 360char* FileMapInfo::map_region(int i, bool address_must_match) { 361 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 362 size_t used = si->_used; 363 size_t size = align_size_up(used, os::vm_allocation_granularity()); 364 char *requested_addr = 0; 365 if (address_must_match) { 366 requested_addr = si->_base; 367 } 368 char *base = os::map_memory(_fd, _full_path, si->_file_offset, 369 requested_addr, size, si->_read_only, 370 si->_allow_exec); 371 if (base == NULL) { 372 fail_continue("Unable to map shared space."); 373 return NULL; 374 } 375 if (address_must_match) { 376 if (base != si->_base) { 377 fail_continue("Unable to map shared space at required address."); 378 return NULL; 379 } 380 } else { 381 si->_base = base; // save mapped address for unmapping. 382 } 383 return base; 384} 385 386 387// Unmap a memory region in the address space. 388 389void FileMapInfo::unmap_region(int i) { 390 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i]; 391 size_t used = si->_used; 392 size_t size = align_size_up(used, os::vm_allocation_granularity()); 393 if (!os::unmap_memory(si->_base, size)) { 394 fail_stop("Unable to unmap shared space."); 395 } 396} 397 398 399void FileMapInfo::assert_mark(bool check) { 400 if (!check) { 401 fail_stop("Mark mismatch while restoring from shared file.", NULL); 402 } 403} 404 405 406FileMapInfo* FileMapInfo::_current_info = NULL; 407 408 409// Open the shared archive file, read and validate the header 410// information (version, boot classpath, etc.). If initialization 411// fails, shared spaces are disabled and the file is closed. [See 412// fail_continue.] 413 414 415bool FileMapInfo::initialize() { 416 assert(UseSharedSpaces, "UseSharedSpaces expected."); 417 418 if (JvmtiExport::can_modify_any_class() || JvmtiExport::can_walk_any_space()) { 419 fail_continue("Tool agent requires sharing to be disabled."); 420 return false; 421 } 422 423 if (!open_for_read()) { 424 return false; 425 } 426 427 init_from_file(_fd); 428 if (!validate()) { 429 return false; 430 } 431 432 SharedReadOnlySize = _header._space[0]._capacity; 433 SharedReadWriteSize = _header._space[1]._capacity; 434 SharedMiscDataSize = _header._space[2]._capacity; 435 SharedMiscCodeSize = _header._space[3]._capacity; 436 return true; 437} 438 439 440bool FileMapInfo::validate() { 441 if (_header._version != current_version()) { 442 fail_continue("The shared archive file is the wrong version."); 443 return false; 444 } 445 if (_header._magic != (int)0xf00baba2) { 446 fail_continue("The shared archive file has a bad magic number."); 447 return false; 448 } 449 if (strncmp(_header._jvm_ident, VM_Version::internal_vm_info_string(), 450 JVM_IDENT_MAX-1) != 0) { 451 fail_continue("The shared archive file was created by a different" 452 " version or build of HotSpot."); 453 return false; 454 } 455 456 // Cannot verify interpreter yet, as it can only be created after the GC 457 // heap has been initialized. 458 459 if (_header._num_jars >= JVM_SHARED_JARS_MAX) { 460 fail_continue("Too many jar files to share."); 461 return false; 462 } 463 464 // Build checks on classpath and jar files 465 int num_jars_now = 0; 466 ClassPathEntry *cpe = ClassLoader::classpath_entry(0); 467 for ( ; cpe != NULL; cpe = cpe->next()) { 468 469 if (cpe->is_jar_file()) { 470 if (num_jars_now < _header._num_jars) { 471 472 // Jar file - verify timestamp and file size. 473 struct stat st; 474 const char *path = cpe->name(); 475 if (os::stat(path, &st) != 0) { 476 fail_continue("Unable to open jar file %s.", path); 477 return false; 478 } 479 if (_header._jar[num_jars_now]._timestamp != st.st_mtime || 480 _header._jar[num_jars_now]._filesize != st.st_size) { 481 fail_continue("A jar file is not the one used while building" 482 " the shared archive file."); 483 return false; 484 } 485 } 486 ++num_jars_now; 487 } else { 488 489 // If directories appear in boot classpath, they must be empty to 490 // avoid having to verify each individual class file. 491 const char* name = ((ClassPathDirEntry*)cpe)->name(); 492 if (!os::dir_is_empty(name)) { 493 fail_continue("Boot classpath directory %s is not empty.", name); 494 return false; 495 } 496 } 497 } 498 if (num_jars_now < _header._num_jars) { 499 fail_continue("The number of jar files in the boot classpath is" 500 " less than the number the shared archive was created with."); 501 return false; 502 } 503 504 return true; 505} 506 507// The following method is provided to see whether a given pointer 508// falls in the mapped shared space. 509// Param: 510// p, The given pointer 511// Return: 512// True if the p is within the mapped shared space, otherwise, false. 513bool FileMapInfo::is_in_shared_space(const void* p) { 514 for (int i = 0; i < CompactingPermGenGen::n_regions; i++) { 515 if (p >= _header._space[i]._base && 516 p < _header._space[i]._base + _header._space[i]._used) { 517 return true; 518 } 519 } 520 521 return false; 522} 523