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