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