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 "runtime/vm_version.hpp"
34 #include "services/memTracker.hpp"
35 #include "utilities/defaultStream.hpp"
36
37 # include <sys/stat.h>
38 # include <errno.h>
39
40 #ifndef O_BINARY // if defined (Win32) use binary files.
41 #define O_BINARY 0 // otherwise do nothing.
42 #endif
43
44 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
45
46 extern address JVM_FunctionAtStart();
47 extern address JVM_FunctionAtEnd();
48
49 // Complain and stop. All error conditions occurring during the writing of
50 // an archive file should stop the process. Unrecoverable errors during
51 // the reading of the archive file should stop the process.
52
53 static void fail(const char *msg, va_list ap) {
54 // This occurs very early during initialization: tty is not initialized.
55 jio_fprintf(defaultStream::error_stream(),
56 "An error has occurred while processing the"
57 " shared archive file.\n");
58 jio_vfprintf(defaultStream::error_stream(), msg, ap);
59 jio_fprintf(defaultStream::error_stream(), "\n");
60 // Do not change the text of the below message because some tests check for it.
61 vm_exit_during_initialization("Unable to use shared archive.", NULL);
62 }
63
64
65 void FileMapInfo::fail_stop(const char *msg, ...) {
66 va_list ap;
67 va_start(ap, msg);
68 fail(msg, ap); // Never returns.
69 va_end(ap); // for completeness.
70 }
71
72
73 // Complain and continue. Recoverable errors during the reading of the
74 // archive file may continue (with sharing disabled).
75 //
76 // If we continue, then disable shared spaces and close the file.
77
78 void FileMapInfo::fail_continue(const char *msg, ...) {
79 va_list ap;
80 va_start(ap, msg);
81 if (RequireSharedSpaces) {
82 fail(msg, ap);
83 } else {
84 if (PrintSharedSpaces) {
85 tty->print_cr("UseSharedSpaces: %s", msg);
86 }
87 }
88 va_end(ap);
89 UseSharedSpaces = false;
90 close();
91 }
92
93 // Fill in the fileMapInfo structure with data about this VM instance.
94
95 // This method copies the vm version info into header_version. If the version is too
96 // long then a truncated version, which has a hash code appended to it, is copied.
97 //
98 // Using a template enables this method to verify that header_version is an array of
99 // length JVM_IDENT_MAX. This ensures that the code that writes to the CDS file and
100 // the code that reads the CDS file will both use the same size buffer. Hence, will
101 // use identical truncation. This is necessary for matching of truncated versions.
102 template <int N> static void get_header_version(char (&header_version) [N]) {
103 assert(N == JVM_IDENT_MAX, "Bad header_version size");
104
105 const char *vm_version = VM_Version::internal_vm_info_string();
106 const int version_len = (int)strlen(vm_version);
107
108 if (version_len < (JVM_IDENT_MAX-1)) {
109 strcpy(header_version, vm_version);
110
111 } else {
112 // Get the hash value. Use a static seed because the hash needs to return the same
113 // value over multiple jvm invocations.
114 unsigned int hash = AltHashing::murmur3_32(8191, (const jbyte*)vm_version, version_len);
115
116 // Truncate the ident, saving room for the 8 hex character hash value.
117 strncpy(header_version, vm_version, JVM_IDENT_MAX-9);
118
119 // Append the hash code as eight hex digits.
120 sprintf(&header_version[JVM_IDENT_MAX-9], "%08x", hash);
121 header_version[JVM_IDENT_MAX-1] = 0; // Null terminate.
122 }
123 }
124
125 void FileMapInfo::populate_header(size_t alignment) {
126 _header._magic = 0xf00baba2;
127 _header._version = _current_version;
128 _header._alignment = alignment;
129 _header._obj_alignment = ObjectAlignmentInBytes;
130
131 // The following fields are for sanity checks for whether this archive
132 // will function correctly with this JVM and the bootclasspath it's
133 // invoked with.
134
135 // JVM version string ... changes on each build.
136 get_header_version(_header._jvm_ident);
137
138 // Build checks on classpath and jar files
139 _header._num_jars = 0;
140 ClassPathEntry *cpe = ClassLoader::classpath_entry(0);
141 for ( ; cpe != NULL; cpe = cpe->next()) {
142
143 if (cpe->is_jar_file()) {
144 if (_header._num_jars >= JVM_SHARED_JARS_MAX) {
145 fail_stop("Too many jar files to share.", NULL);
146 }
147
148 // Jar file - record timestamp and file size.
149 struct stat st;
150 const char *path = cpe->name();
151 if (os::stat(path, &st) != 0) {
152 // If we can't access a jar file in the boot path, then we can't
153 // make assumptions about where classes get loaded from.
154 fail_stop("Unable to open jar file %s.", path);
155 }
156 _header._jar[_header._num_jars]._timestamp = st.st_mtime;
157 _header._jar[_header._num_jars]._filesize = st.st_size;
158 _header._num_jars++;
159 } else {
160
161 // If directories appear in boot classpath, they must be empty to
162 // avoid having to verify each individual class file.
163 const char* name = ((ClassPathDirEntry*)cpe)->name();
164 if (!os::dir_is_empty(name)) {
165 fail_stop("Boot classpath directory %s is not empty.", name);
166 }
167 }
168 }
169 }
170
171
172 // Read the FileMapInfo information from the file.
173
174 bool FileMapInfo::init_from_file(int fd) {
175
176 size_t n = read(fd, &_header, sizeof(struct FileMapHeader));
177 if (n != sizeof(struct FileMapHeader)) {
178 fail_continue("Unable to read the file header.");
179 return false;
180 }
181 if (_header._version != current_version()) {
182 fail_continue("The shared archive file has the wrong version.");
183 return false;
184 }
185 _file_offset = (long)n;
186 return true;
187 }
188
189
190 // Read the FileMapInfo information from the file.
191 bool FileMapInfo::open_for_read() {
192 _full_path = Arguments::GetSharedArchivePath();
193 int fd = open(_full_path, O_RDONLY | O_BINARY, 0);
194 if (fd < 0) {
195 if (errno == ENOENT) {
196 // Not locating the shared archive is ok.
197 fail_continue("Specified shared archive not found.");
198 } else {
199 fail_continue("Failed to open shared archive file (%s).",
200 strerror(errno));
201 }
202 return false;
203 }
204
205 _fd = fd;
206 _file_open = true;
207 return true;
208 }
209
210
211 // Write the FileMapInfo information to the file.
212
213 void FileMapInfo::open_for_write() {
214 _full_path = Arguments::GetSharedArchivePath();
215 if (PrintSharedSpaces) {
216 tty->print_cr("Dumping shared data to file: ");
217 tty->print_cr(" %s", _full_path);
218 }
219
220 #ifdef _WINDOWS // On Windows, need WRITE permission to remove the file.
221 chmod(_full_path, _S_IREAD | _S_IWRITE);
222 #endif
223
224 // Use remove() to delete the existing file because, on Unix, this will
225 // allow processes that have it open continued access to the file.
226 remove(_full_path);
227 int fd = open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0444);
228 if (fd < 0) {
229 fail_stop("Unable to create shared archive file %s.", _full_path);
230 }
231 _fd = fd;
232 _file_offset = 0;
233 _file_open = true;
234 }
235
236
237 // Write the header to the file, seek to the next allocation boundary.
238
239 void FileMapInfo::write_header() {
240 write_bytes_aligned(&_header, sizeof(FileMapHeader));
241 }
242
243
244 // Dump shared spaces to file.
245
246 void FileMapInfo::write_space(int i, Metaspace* space, bool read_only) {
247 align_file_position();
248 size_t used = space->used_bytes_slow(Metaspace::NonClassType);
249 size_t capacity = space->capacity_bytes_slow(Metaspace::NonClassType);
250 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
251 write_region(i, (char*)space->bottom(), used, capacity, read_only, false);
252 }
253
254
255 // Dump region to file.
256
257 void FileMapInfo::write_region(int region, char* base, size_t size,
258 size_t capacity, bool read_only,
259 bool allow_exec) {
260 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[region];
261
262 if (_file_open) {
263 guarantee(si->_file_offset == _file_offset, "file offset mismatch.");
264 if (PrintSharedSpaces) {
265 tty->print_cr("Shared file region %d: 0x%6x bytes, addr " INTPTR_FORMAT
266 " file offset 0x%6x", region, size, base, _file_offset);
267 }
268 } else {
269 si->_file_offset = _file_offset;
270 }
271 si->_base = base;
272 si->_used = size;
273 si->_capacity = capacity;
274 si->_read_only = read_only;
275 si->_allow_exec = allow_exec;
276 write_bytes_aligned(base, (int)size);
277 }
278
279
280 // Dump bytes to file -- at the current file position.
281
282 void FileMapInfo::write_bytes(const void* buffer, int nbytes) {
283 if (_file_open) {
284 int n = ::write(_fd, buffer, nbytes);
285 if (n != nbytes) {
286 // It is dangerous to leave the corrupted shared archive file around,
287 // close and remove the file. See bug 6372906.
288 close();
289 remove(_full_path);
290 fail_stop("Unable to write to shared archive file.", NULL);
291 }
292 }
293 _file_offset += nbytes;
294 }
295
296
297 // Align file position to an allocation unit boundary.
298
299 void FileMapInfo::align_file_position() {
300 long new_file_offset = align_size_up(_file_offset, os::vm_allocation_granularity());
301 if (new_file_offset != _file_offset) {
302 _file_offset = new_file_offset;
303 if (_file_open) {
304 // Seek one byte back from the target and write a byte to insure
305 // that the written file is the correct length.
306 _file_offset -= 1;
307 if (lseek(_fd, _file_offset, SEEK_SET) < 0) {
308 fail_stop("Unable to seek.", NULL);
309 }
310 char zero = 0;
311 write_bytes(&zero, 1);
312 }
313 }
314 }
315
316
317 // Dump bytes to file -- at the current file position.
318
319 void FileMapInfo::write_bytes_aligned(const void* buffer, int nbytes) {
320 align_file_position();
321 write_bytes(buffer, nbytes);
322 align_file_position();
323 }
324
325
326 // Close the shared archive file. This does NOT unmap mapped regions.
327
328 void FileMapInfo::close() {
329 if (_file_open) {
330 if (::close(_fd) < 0) {
331 fail_stop("Unable to close the shared archive file.");
332 }
333 _file_open = false;
334 _fd = -1;
335 }
336 }
337
338
339 // JVM/TI RedefineClasses() support:
340 // Remap the shared readonly space to shared readwrite, private.
341 bool FileMapInfo::remap_shared_readonly_as_readwrite() {
342 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0];
343 if (!si->_read_only) {
344 // the space is already readwrite so we are done
345 return true;
346 }
347 size_t used = si->_used;
348 size_t size = align_size_up(used, os::vm_allocation_granularity());
349 if (!open_for_read()) {
350 return false;
351 }
352 char *base = os::remap_memory(_fd, _full_path, si->_file_offset,
353 si->_base, size, false /* !read_only */,
354 si->_allow_exec);
355 close();
356 if (base == NULL) {
357 fail_continue("Unable to remap shared readonly space (errno=%d).", errno);
358 return false;
359 }
360 if (base != si->_base) {
361 fail_continue("Unable to remap shared readonly space at required address.");
362 return false;
363 }
364 si->_read_only = false;
365 return true;
366 }
367
368 // Map the whole region at once, assumed to be allocated contiguously.
369 ReservedSpace FileMapInfo::reserve_shared_memory() {
370 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0];
371 char* requested_addr = si->_base;
372
373 size_t size = FileMapInfo::shared_spaces_size();
374
375 // Reserve the space first, then map otherwise map will go right over some
376 // other reserved memory (like the code cache).
377 ReservedSpace rs(size, os::vm_allocation_granularity(), false, requested_addr);
378 if (!rs.is_reserved()) {
379 fail_continue(err_msg("Unable to reserve shared space at required address " INTPTR_FORMAT, requested_addr));
380 return rs;
381 }
382 // the reserved virtual memory is for mapping class data sharing archive
383 MemTracker::record_virtual_memory_type((address)rs.base(), mtClassShared);
384
385 return rs;
386 }
387
388 // Memory map a region in the address space.
389 static const char* shared_region_name[] = { "ReadOnly", "ReadWrite", "MiscData", "MiscCode"};
390
391 char* FileMapInfo::map_region(int i) {
392 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
393 size_t used = si->_used;
394 size_t alignment = os::vm_allocation_granularity();
395 size_t size = align_size_up(used, alignment);
396 char *requested_addr = si->_base;
397
398 // map the contents of the CDS archive in this memory
399 char *base = os::map_memory(_fd, _full_path, si->_file_offset,
400 requested_addr, size, si->_read_only,
401 si->_allow_exec);
402 if (base == NULL || base != si->_base) {
403 fail_continue(err_msg("Unable to map %s shared space at required address.", shared_region_name[i]));
404 return NULL;
405 }
406 #ifdef _WINDOWS
407 // This call is Windows-only because the memory_type gets recorded for the other platforms
408 // in method FileMapInfo::reserve_shared_memory(), which is not called on Windows.
409 MemTracker::record_virtual_memory_type((address)base, mtClassShared);
410 #endif
411 return base;
412 }
413
414
415 // Unmap a memory region in the address space.
416
417 void FileMapInfo::unmap_region(int i) {
418 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
419 size_t used = si->_used;
420 size_t size = align_size_up(used, os::vm_allocation_granularity());
421 if (!os::unmap_memory(si->_base, size)) {
422 fail_stop("Unable to unmap shared space.");
423 }
424 }
425
426
427 void FileMapInfo::assert_mark(bool check) {
428 if (!check) {
429 fail_stop("Mark mismatch while restoring from shared file.", NULL);
430 }
431 }
432
433
434 FileMapInfo* FileMapInfo::_current_info = NULL;
435
436
437 // Open the shared archive file, read and validate the header
438 // information (version, boot classpath, etc.). If initialization
439 // fails, shared spaces are disabled and the file is closed. [See
440 // fail_continue.]
441 bool FileMapInfo::initialize() {
442 assert(UseSharedSpaces, "UseSharedSpaces expected.");
443
444 if (JvmtiExport::can_modify_any_class() || JvmtiExport::can_walk_any_space()) {
445 fail_continue("Tool agent requires sharing to be disabled.");
446 return false;
447 }
448
449 if (!open_for_read()) {
450 return false;
451 }
452
453 init_from_file(_fd);
454 if (!validate()) {
455 return false;
456 }
457
458 SharedReadOnlySize = _header._space[0]._capacity;
459 SharedReadWriteSize = _header._space[1]._capacity;
460 SharedMiscDataSize = _header._space[2]._capacity;
461 SharedMiscCodeSize = _header._space[3]._capacity;
462 return true;
463 }
464
465
466 bool FileMapInfo::validate() {
467 if (_header._version != current_version()) {
468 fail_continue("The shared archive file is the wrong version.");
469 return false;
470 }
471 if (_header._magic != (int)0xf00baba2) {
472 fail_continue("The shared archive file has a bad magic number.");
473 return false;
474 }
475 char header_version[JVM_IDENT_MAX];
476 get_header_version(header_version);
477 if (strncmp(_header._jvm_ident, header_version, JVM_IDENT_MAX-1) != 0) {
478 fail_continue("The shared archive file was created by a different"
479 " version or build of HotSpot.");
480 return false;
481 }
482 if (_header._obj_alignment != ObjectAlignmentInBytes) {
483 fail_continue("The shared archive file's ObjectAlignmentInBytes of %d"
484 " does not equal the current ObjectAlignmentInBytes of %d.",
485 _header._obj_alignment, ObjectAlignmentInBytes);
486 return false;
487 }
488
489 // Cannot verify interpreter yet, as it can only be created after the GC
490 // heap has been initialized.
491
492 if (_header._num_jars >= JVM_SHARED_JARS_MAX) {
493 fail_continue("Too many jar files to share.");
494 return false;
495 }
496
497 // Build checks on classpath and jar files
498 int num_jars_now = 0;
499 ClassPathEntry *cpe = ClassLoader::classpath_entry(0);
500 for ( ; cpe != NULL; cpe = cpe->next()) {
501
502 if (cpe->is_jar_file()) {
503 if (num_jars_now < _header._num_jars) {
504
505 // Jar file - verify timestamp and file size.
506 struct stat st;
507 const char *path = cpe->name();
508 if (os::stat(path, &st) != 0) {
509 fail_continue("Unable to open jar file %s.", path);
510 return false;
511 }
512 if (_header._jar[num_jars_now]._timestamp != st.st_mtime ||
513 _header._jar[num_jars_now]._filesize != st.st_size) {
514 fail_continue("A jar file is not the one used while building"
515 " the shared archive file.");
516 return false;
517 }
518 }
519 ++num_jars_now;
520 } else {
521
522 // If directories appear in boot classpath, they must be empty to
523 // avoid having to verify each individual class file.
524 const char* name = ((ClassPathDirEntry*)cpe)->name();
525 if (!os::dir_is_empty(name)) {
526 fail_continue("Boot classpath directory %s is not empty.", name);
527 return false;
528 }
529 }
530 }
531 if (num_jars_now < _header._num_jars) {
532 fail_continue("The number of jar files in the boot classpath is"
533 " less than the number the shared archive was created with.");
534 return false;
535 }
536
537 return true;
538 }
539
540 // The following method is provided to see whether a given pointer
541 // falls in the mapped shared space.
542 // Param:
543 // p, The given pointer
544 // Return:
545 // True if the p is within the mapped shared space, otherwise, false.
546 bool FileMapInfo::is_in_shared_space(const void* p) {
547 for (int i = 0; i < MetaspaceShared::n_regions; i++) {
548 if (p >= _header._space[i]._base &&
549 p < _header._space[i]._base + _header._space[i]._used) {
550 return true;
551 }
552 }
553
554 return false;
555 }
556
557 void FileMapInfo::print_shared_spaces() {
558 gclog_or_tty->print_cr("Shared Spaces:");
559 for (int i = 0; i < MetaspaceShared::n_regions; i++) {
560 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
561 gclog_or_tty->print(" %s " INTPTR_FORMAT "-" INTPTR_FORMAT,
562 shared_region_name[i],
563 si->_base, si->_base + si->_used);
564 }
565 }
566
567 // Unmap mapped regions of shared space.
568 void FileMapInfo::stop_sharing_and_unmap(const char* msg) {
569 FileMapInfo *map_info = FileMapInfo::current_info();
570 if (map_info) {
571 map_info->fail_continue(msg);
572 for (int i = 0; i < MetaspaceShared::n_regions; i++) {
573 if (map_info->_header._space[i]._base != NULL) {
574 map_info->unmap_region(i);
575 map_info->_header._space[i]._base = NULL;
576 }
577 }
578 } else if (DumpSharedSpaces) {
579 fail_stop(msg, NULL);
580 }
581 }