1 /*
2 * Copyright (c) 2003, 2006, 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 "incls/_precompiled.incl"
26 # include "incls/_filemap.cpp.incl"
27 # include <sys/stat.h>
28 # include <errno.h>
29
30 #ifndef O_BINARY // if defined (Win32) use binary files.
31 #define O_BINARY 0 // otherwise do nothing.
32 #endif
33
34
35 extern address JVM_FunctionAtStart();
36 extern address JVM_FunctionAtEnd();
37
38 // Complain and stop. All error conditions occurring during the writing of
39 // an archive file should stop the process. Unrecoverable errors during
40 // the reading of the archive file should stop the process.
41
42 static void fail(const char *msg, va_list ap) {
43 // This occurs very early during initialization: tty is not initialized.
44 jio_fprintf(defaultStream::error_stream(),
45 "An error has occurred while processing the"
46 " shared archive file.\n");
47 jio_vfprintf(defaultStream::error_stream(), msg, ap);
48 jio_fprintf(defaultStream::error_stream(), "\n");
49 vm_exit_during_initialization("Unable to use shared archive.", NULL);
50 }
51
52
53 void FileMapInfo::fail_stop(const char *msg, ...) {
54 va_list ap;
55 va_start(ap, msg);
56 fail(msg, ap); // Never returns.
57 va_end(ap); // for completeness.
58 }
59
60
61 // Complain and continue. Recoverable errors during the reading of the
62 // archive file may continue (with sharing disabled).
63 //
64 // If we continue, then disable shared spaces and close the file.
65
66 void FileMapInfo::fail_continue(const char *msg, ...) {
67 va_list ap;
68 va_start(ap, msg);
69 if (RequireSharedSpaces) {
70 fail(msg, ap);
71 }
72 va_end(ap);
73 UseSharedSpaces = false;
74 close();
75 }
76
77
78 // Fill in the fileMapInfo structure with data about this VM instance.
79
80 void FileMapInfo::populate_header(size_t alignment) {
81 _header._magic = 0xf00baba2;
82 _header._version = _current_version;
83 _header._alignment = alignment;
84
85 // The following fields are for sanity checks for whether this archive
86 // will function correctly with this JVM and the bootclasspath it's
87 // invoked with.
88
89 // JVM version string ... changes on each build.
90 const char *vm_version = VM_Version::internal_vm_info_string();
91 if (strlen(vm_version) < (JVM_IDENT_MAX-1)) {
92 strcpy(_header._jvm_ident, vm_version);
93 } else {
94 fail_stop("JVM Ident field for shared archive is too long"
95 " - truncated to <%s>", _header._jvm_ident);
96 }
97
98 // Build checks on classpath and jar files
99 _header._num_jars = 0;
100 ClassPathEntry *cpe = ClassLoader::classpath_entry(0);
101 for ( ; cpe != NULL; cpe = cpe->next()) {
102
103 if (cpe->is_jar_file()) {
104 if (_header._num_jars >= JVM_SHARED_JARS_MAX) {
105 fail_stop("Too many jar files to share.", NULL);
106 }
107
108 // Jar file - record timestamp and file size.
109 struct stat st;
110 const char *path = cpe->name();
111 if (os::stat(path, &st) != 0) {
112 // If we can't access a jar file in the boot path, then we can't
113 // make assumptions about where classes get loaded from.
114 fail_stop("Unable to open jar file %s.", path);
115 }
116 _header._jar[_header._num_jars]._timestamp = st.st_mtime;
117 _header._jar[_header._num_jars]._filesize = st.st_size;
118 _header._num_jars++;
119 } else {
120
121 // If directories appear in boot classpath, they must be empty to
122 // avoid having to verify each individual class file.
123 const char* name = ((ClassPathDirEntry*)cpe)->name();
124 if (!os::dir_is_empty(name)) {
125 fail_stop("Boot classpath directory %s is not empty.", name);
126 }
127 }
128 }
129 }
130
131
132 // Read the FileMapInfo information from the file.
133
134 bool FileMapInfo::init_from_file(int fd) {
135
136 size_t n = read(fd, &_header, sizeof(struct FileMapHeader));
137 if (n != sizeof(struct FileMapHeader)) {
138 fail_continue("Unable to read the file header.");
139 return false;
140 }
141 if (_header._version != current_version()) {
142 fail_continue("The shared archive file has the wrong version.");
143 return false;
144 }
145 _file_offset = (long)n;
146 return true;
147 }
148
149
150 // Read the FileMapInfo information from the file.
151 bool FileMapInfo::open_for_read() {
152 _full_path = Arguments::GetSharedArchivePath();
153 int fd = open(_full_path, O_RDONLY | O_BINARY, 0);
154 if (fd < 0) {
155 if (errno == ENOENT) {
156 // Not locating the shared archive is ok.
157 fail_continue("Specified shared archive not found.");
158 } else {
159 fail_continue("Failed to open shared archive file (%s).",
160 strerror(errno));
161 }
162 return false;
163 }
164
165 _fd = fd;
166 _file_open = true;
167 return true;
168 }
169
170
171 // Write the FileMapInfo information to the file.
172
173 void FileMapInfo::open_for_write() {
174 _full_path = Arguments::GetSharedArchivePath();
175 if (PrintSharedSpaces) {
176 tty->print_cr("Dumping shared data to file: ");
177 tty->print_cr(" %s", _full_path);
178 }
179
180 // Remove the existing file in case another process has it open.
181 remove(_full_path);
182 int fd = open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0444);
183 if (fd < 0) {
184 fail_stop("Unable to create shared archive file %s.", _full_path);
185 }
186 _fd = fd;
187 _file_offset = 0;
188 _file_open = true;
189 }
190
191
192 // Write the header to the file, seek to the next allocation boundary.
193
194 void FileMapInfo::write_header() {
195 write_bytes_aligned(&_header, sizeof(FileMapHeader));
196 }
197
198
199 // Dump shared spaces to file.
200
201 void FileMapInfo::write_space(int i, CompactibleSpace* space, bool read_only) {
202 align_file_position();
203 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
204 write_region(i, (char*)space->bottom(), space->used(),
205 space->capacity(), read_only, false);
206 }
207
208
209 // Dump region to file.
210
211 void FileMapInfo::write_region(int region, char* base, size_t size,
212 size_t capacity, bool read_only,
213 bool allow_exec) {
214 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[region];
215
216 if (_file_open) {
217 guarantee(si->_file_offset == _file_offset, "file offset mismatch.");
218 if (PrintSharedSpaces) {
219 tty->print_cr("Shared file region %d: 0x%x bytes, addr 0x%x,"
220 " file offset 0x%x", region, size, base, _file_offset);
221 }
222 } else {
223 si->_file_offset = _file_offset;
224 }
225 si->_base = base;
226 si->_used = size;
227 si->_capacity = capacity;
228 si->_read_only = read_only;
229 si->_allow_exec = allow_exec;
230 write_bytes_aligned(base, (int)size);
231 }
232
233
234 // Dump bytes to file -- at the current file position.
235
236 void FileMapInfo::write_bytes(const void* buffer, int nbytes) {
237 if (_file_open) {
238 int n = ::write(_fd, buffer, nbytes);
239 if (n != nbytes) {
240 // It is dangerous to leave the corrupted shared archive file around,
241 // close and remove the file. See bug 6372906.
242 close();
243 remove(_full_path);
244 fail_stop("Unable to write to shared archive file.", NULL);
245 }
246 }
247 _file_offset += nbytes;
248 }
249
250
251 // Align file position to an allocation unit boundary.
252
253 void FileMapInfo::align_file_position() {
254 long new_file_offset = align_size_up(_file_offset, os::vm_allocation_granularity());
255 if (new_file_offset != _file_offset) {
256 _file_offset = new_file_offset;
257 if (_file_open) {
258 // Seek one byte back from the target and write a byte to insure
259 // that the written file is the correct length.
260 _file_offset -= 1;
261 if (lseek(_fd, _file_offset, SEEK_SET) < 0) {
262 fail_stop("Unable to seek.", NULL);
263 }
264 char zero = 0;
265 write_bytes(&zero, 1);
266 }
267 }
268 }
269
270
271 // Dump bytes to file -- at the current file position.
272
273 void FileMapInfo::write_bytes_aligned(const void* buffer, int nbytes) {
274 align_file_position();
275 write_bytes(buffer, nbytes);
276 align_file_position();
277 }
278
279
280 // Close the shared archive file. This does NOT unmap mapped regions.
281
282 void FileMapInfo::close() {
283 if (_file_open) {
284 if (::close(_fd) < 0) {
285 fail_stop("Unable to close the shared archive file.");
286 }
287 _file_open = false;
288 _fd = -1;
289 }
290 }
291
292
293 // Memory map a shared space from the archive file.
294
295 bool FileMapInfo::map_space(int i, ReservedSpace rs, ContiguousSpace* space) {
296 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
297 if (space != NULL) {
298 if (si->_base != (char*)space->bottom() ||
299 si->_capacity != space->capacity()) {
300 fail_continue("Shared space base address does not match.");
301 return false;
302 }
303 }
304 bool result = (map_region(i, rs) != NULL);
305 if (space != NULL && result) {
306 space->set_top((HeapWord*)(si->_base + si->_used));
307 space->set_saved_mark();
308 }
309 return result;
310 }
311
312
313 // JVM/TI RedefineClasses() support:
314 // Remap the shared readonly space to shared readwrite, private.
315 bool FileMapInfo::remap_shared_readonly_as_readwrite() {
316 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0];
317 if (!si->_read_only) {
318 // the space is already readwrite so we are done
319 return true;
320 }
321 size_t used = si->_used;
322 size_t size = align_size_up(used, os::vm_allocation_granularity());
323 if (!open_for_read()) {
324 return false;
325 }
326 char *base = os::remap_memory(_fd, _full_path, si->_file_offset,
327 si->_base, size, false /* !read_only */,
328 si->_allow_exec);
329 close();
330 if (base == NULL) {
331 fail_continue("Unable to remap shared readonly space (errno=%d).", errno);
332 return false;
333 }
334 if (base != si->_base) {
335 fail_continue("Unable to remap shared readonly space at required address.");
336 return false;
337 }
338 si->_read_only = false;
339 return true;
340 }
341
342
343 // Memory map a region in the address space.
344
345 char* FileMapInfo::map_region(int i, ReservedSpace rs) {
346 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
347 size_t used = si->_used;
348 size_t size = align_size_up(used, os::vm_allocation_granularity());
349
350 ReservedSpace mapped_rs = rs.first_part(size, true, true);
351 ReservedSpace unmapped_rs = rs.last_part(size);
352 mapped_rs.release();
353
354 return map_region(i, true);
355 }
356
357
358 // Memory map a region in the address space.
359
360 char* FileMapInfo::map_region(int i, bool address_must_match) {
361 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
362 size_t used = si->_used;
363 size_t size = align_size_up(used, os::vm_allocation_granularity());
364 char *requested_addr = 0;
365 if (address_must_match) {
366 requested_addr = si->_base;
367 }
368 char *base = os::map_memory(_fd, _full_path, si->_file_offset,
369 requested_addr, size, si->_read_only,
370 si->_allow_exec);
371 if (base == NULL) {
372 fail_continue("Unable to map shared space.");
373 return NULL;
374 }
375 if (address_must_match) {
376 if (base != si->_base) {
377 fail_continue("Unable to map shared space at required address.");
378 return NULL;
379 }
380 } else {
381 si->_base = base; // save mapped address for unmapping.
382 }
383 return base;
384 }
385
386
387 // Unmap a memory region in the address space.
388
389 void FileMapInfo::unmap_region(int i) {
390 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
391 size_t used = si->_used;
392 size_t size = align_size_up(used, os::vm_allocation_granularity());
393 if (!os::unmap_memory(si->_base, size)) {
394 fail_stop("Unable to unmap shared space.");
395 }
396 }
397
398
399 void FileMapInfo::assert_mark(bool check) {
400 if (!check) {
401 fail_stop("Mark mismatch while restoring from shared file.", NULL);
402 }
403 }
404
405
406 FileMapInfo* FileMapInfo::_current_info = NULL;
407
408
409 // Open the shared archive file, read and validate the header
410 // information (version, boot classpath, etc.). If initialization
411 // fails, shared spaces are disabled and the file is closed. [See
412 // fail_continue.]
413
414
415 bool FileMapInfo::initialize() {
416 assert(UseSharedSpaces, "UseSharedSpaces expected.");
417
418 if (JvmtiExport::can_modify_any_class() || JvmtiExport::can_walk_any_space()) {
419 fail_continue("Tool agent requires sharing to be disabled.");
420 return false;
421 }
422
423 if (!open_for_read()) {
424 return false;
425 }
426
427 init_from_file(_fd);
428 if (!validate()) {
429 return false;
430 }
431
432 SharedReadOnlySize = _header._space[0]._capacity;
433 SharedReadWriteSize = _header._space[1]._capacity;
434 SharedMiscDataSize = _header._space[2]._capacity;
435 SharedMiscCodeSize = _header._space[3]._capacity;
436 return true;
437 }
438
439
440 bool FileMapInfo::validate() {
441 if (_header._version != current_version()) {
442 fail_continue("The shared archive file is the wrong version.");
443 return false;
444 }
445 if (_header._magic != (int)0xf00baba2) {
446 fail_continue("The shared archive file has a bad magic number.");
447 return false;
448 }
449 if (strncmp(_header._jvm_ident, VM_Version::internal_vm_info_string(),
450 JVM_IDENT_MAX-1) != 0) {
451 fail_continue("The shared archive file was created by a different"
452 " version or build of HotSpot.");
453 return false;
454 }
455
456 // Cannot verify interpreter yet, as it can only be created after the GC
457 // heap has been initialized.
458
459 if (_header._num_jars >= JVM_SHARED_JARS_MAX) {
460 fail_continue("Too many jar files to share.");
461 return false;
462 }
463
464 // Build checks on classpath and jar files
465 int num_jars_now = 0;
466 ClassPathEntry *cpe = ClassLoader::classpath_entry(0);
467 for ( ; cpe != NULL; cpe = cpe->next()) {
468
469 if (cpe->is_jar_file()) {
470 if (num_jars_now < _header._num_jars) {
471
472 // Jar file - verify timestamp and file size.
473 struct stat st;
474 const char *path = cpe->name();
475 if (os::stat(path, &st) != 0) {
476 fail_continue("Unable to open jar file %s.", path);
477 return false;
478 }
479 if (_header._jar[num_jars_now]._timestamp != st.st_mtime ||
480 _header._jar[num_jars_now]._filesize != st.st_size) {
481 fail_continue("A jar file is not the one used while building"
482 " the shared archive file.");
483 return false;
484 }
485 }
486 ++num_jars_now;
487 } else {
488
489 // If directories appear in boot classpath, they must be empty to
490 // avoid having to verify each individual class file.
491 const char* name = ((ClassPathDirEntry*)cpe)->name();
492 if (!os::dir_is_empty(name)) {
493 fail_continue("Boot classpath directory %s is not empty.", name);
494 return false;
495 }
496 }
497 }
498 if (num_jars_now < _header._num_jars) {
499 fail_continue("The number of jar files in the boot classpath is"
500 " less than the number the shared archive was created with.");
501 return false;
502 }
503
504 return true;
505 }
506
507 // The following method is provided to see whether a given pointer
508 // falls in the mapped shared space.
509 // Param:
510 // p, The given pointer
511 // Return:
512 // True if the p is within the mapped shared space, otherwise, false.
513 bool FileMapInfo::is_in_shared_space(const void* p) {
514 for (int i = 0; i < CompactingPermGenGen::n_regions; i++) {
515 if (p >= _header._space[i]._base &&
516 p < _header._space[i]._base + _header._space[i]._used) {
517 return true;
518 }
519 }
520
521 return false;
522 }