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