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