Mon, 17 Sep 2012 10:46:59 -0400
7197269: NPG: FollowReferences has no ClassLoader -> Class link to follow
Summary: restore java/lang/ClassLoader.addClass() upcall
Reviewed-by: sspitsyn, dcubed, jmasa
1 /*
2 * Copyright (c) 2003, 2012, 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 */
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "memory/filemap.hpp"
29 #include "runtime/arguments.hpp"
30 #include "runtime/java.hpp"
31 #include "runtime/os.hpp"
32 #include "utilities/defaultStream.hpp"
34 # include <sys/stat.h>
35 # include <errno.h>
37 #ifndef O_BINARY // if defined (Win32) use binary files.
38 #define O_BINARY 0 // otherwise do nothing.
39 #endif
42 extern address JVM_FunctionAtStart();
43 extern address JVM_FunctionAtEnd();
45 // Complain and stop. All error conditions occurring during the writing of
46 // an archive file should stop the process. Unrecoverable errors during
47 // the reading of the archive file should stop the process.
49 static void fail(const char *msg, va_list ap) {
50 // This occurs very early during initialization: tty is not initialized.
51 jio_fprintf(defaultStream::error_stream(),
52 "An error has occurred while processing the"
53 " shared archive file.\n");
54 jio_vfprintf(defaultStream::error_stream(), msg, ap);
55 jio_fprintf(defaultStream::error_stream(), "\n");
56 vm_exit_during_initialization("Unable to use shared archive.", NULL);
57 }
60 void FileMapInfo::fail_stop(const char *msg, ...) {
61 va_list ap;
62 va_start(ap, msg);
63 fail(msg, ap); // Never returns.
64 va_end(ap); // for completeness.
65 }
68 // Complain and continue. Recoverable errors during the reading of the
69 // archive file may continue (with sharing disabled).
70 //
71 // If we continue, then disable shared spaces and close the file.
73 void FileMapInfo::fail_continue(const char *msg, ...) {
74 va_list ap;
75 va_start(ap, msg);
76 if (RequireSharedSpaces) {
77 fail(msg, ap);
78 }
79 va_end(ap);
80 UseSharedSpaces = false;
81 close();
82 }
85 // Fill in the fileMapInfo structure with data about this VM instance.
87 void FileMapInfo::populate_header(size_t alignment) {
88 _header._magic = 0xf00baba2;
89 _header._version = _current_version;
90 _header._alignment = alignment;
92 // The following fields are for sanity checks for whether this archive
93 // will function correctly with this JVM and the bootclasspath it's
94 // invoked with.
96 // JVM version string ... changes on each build.
97 const char *vm_version = VM_Version::internal_vm_info_string();
98 if (strlen(vm_version) < (JVM_IDENT_MAX-1)) {
99 strcpy(_header._jvm_ident, vm_version);
100 } else {
101 fail_stop("JVM Ident field for shared archive is too long"
102 " - truncated to <%s>", _header._jvm_ident);
103 }
105 // Build checks on classpath and jar files
106 _header._num_jars = 0;
107 ClassPathEntry *cpe = ClassLoader::classpath_entry(0);
108 for ( ; cpe != NULL; cpe = cpe->next()) {
110 if (cpe->is_jar_file()) {
111 if (_header._num_jars >= JVM_SHARED_JARS_MAX) {
112 fail_stop("Too many jar files to share.", NULL);
113 }
115 // Jar file - record timestamp and file size.
116 struct stat st;
117 const char *path = cpe->name();
118 if (os::stat(path, &st) != 0) {
119 // If we can't access a jar file in the boot path, then we can't
120 // make assumptions about where classes get loaded from.
121 fail_stop("Unable to open jar file %s.", path);
122 }
123 _header._jar[_header._num_jars]._timestamp = st.st_mtime;
124 _header._jar[_header._num_jars]._filesize = st.st_size;
125 _header._num_jars++;
126 } else {
128 // If directories appear in boot classpath, they must be empty to
129 // avoid having to verify each individual class file.
130 const char* name = ((ClassPathDirEntry*)cpe)->name();
131 if (!os::dir_is_empty(name)) {
132 fail_stop("Boot classpath directory %s is not empty.", name);
133 }
134 }
135 }
136 }
139 // Read the FileMapInfo information from the file.
141 bool FileMapInfo::init_from_file(int fd) {
143 size_t n = read(fd, &_header, sizeof(struct FileMapHeader));
144 if (n != sizeof(struct FileMapHeader)) {
145 fail_continue("Unable to read the file header.");
146 return false;
147 }
148 if (_header._version != current_version()) {
149 fail_continue("The shared archive file has the wrong version.");
150 return false;
151 }
152 _file_offset = (long)n;
153 return true;
154 }
157 // Read the FileMapInfo information from the file.
158 bool FileMapInfo::open_for_read() {
159 _full_path = Arguments::GetSharedArchivePath();
160 int fd = open(_full_path, O_RDONLY | O_BINARY, 0);
161 if (fd < 0) {
162 if (errno == ENOENT) {
163 // Not locating the shared archive is ok.
164 fail_continue("Specified shared archive not found.");
165 } else {
166 fail_continue("Failed to open shared archive file (%s).",
167 strerror(errno));
168 }
169 return false;
170 }
172 _fd = fd;
173 _file_open = true;
174 return true;
175 }
178 // Write the FileMapInfo information to the file.
180 void FileMapInfo::open_for_write() {
181 _full_path = Arguments::GetSharedArchivePath();
182 if (PrintSharedSpaces) {
183 tty->print_cr("Dumping shared data to file: ");
184 tty->print_cr(" %s", _full_path);
185 }
187 // Remove the existing file in case another process has it open.
188 remove(_full_path);
189 int fd = open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0444);
190 if (fd < 0) {
191 fail_stop("Unable to create shared archive file %s.", _full_path);
192 }
193 _fd = fd;
194 _file_offset = 0;
195 _file_open = true;
196 }
199 // Write the header to the file, seek to the next allocation boundary.
201 void FileMapInfo::write_header() {
202 write_bytes_aligned(&_header, sizeof(FileMapHeader));
203 }
206 // Dump shared spaces to file.
208 void FileMapInfo::write_space(int i, Metaspace* space, bool read_only) {
209 align_file_position();
210 size_t used = space->used_words(Metaspace::NonClassType) * BytesPerWord;
211 size_t capacity = space->capacity_words(Metaspace::NonClassType) * BytesPerWord;
212 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
213 write_region(i, (char*)space->bottom(), used, capacity, read_only, false);
214 }
217 // Dump region to file.
219 void FileMapInfo::write_region(int region, char* base, size_t size,
220 size_t capacity, bool read_only,
221 bool allow_exec) {
222 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[region];
224 if (_file_open) {
225 guarantee(si->_file_offset == _file_offset, "file offset mismatch.");
226 if (PrintSharedSpaces) {
227 tty->print_cr("Shared file region %d: 0x%6x bytes, addr " INTPTR_FORMAT
228 " file offset 0x%6x", region, size, base, _file_offset);
229 }
230 } else {
231 si->_file_offset = _file_offset;
232 }
233 si->_base = base;
234 si->_used = size;
235 si->_capacity = capacity;
236 si->_read_only = read_only;
237 si->_allow_exec = allow_exec;
238 write_bytes_aligned(base, (int)size);
239 }
242 // Dump bytes to file -- at the current file position.
244 void FileMapInfo::write_bytes(const void* buffer, int nbytes) {
245 if (_file_open) {
246 int n = ::write(_fd, buffer, nbytes);
247 if (n != nbytes) {
248 // It is dangerous to leave the corrupted shared archive file around,
249 // close and remove the file. See bug 6372906.
250 close();
251 remove(_full_path);
252 fail_stop("Unable to write to shared archive file.", NULL);
253 }
254 }
255 _file_offset += nbytes;
256 }
259 // Align file position to an allocation unit boundary.
261 void FileMapInfo::align_file_position() {
262 long new_file_offset = align_size_up(_file_offset, os::vm_allocation_granularity());
263 if (new_file_offset != _file_offset) {
264 _file_offset = new_file_offset;
265 if (_file_open) {
266 // Seek one byte back from the target and write a byte to insure
267 // that the written file is the correct length.
268 _file_offset -= 1;
269 if (lseek(_fd, _file_offset, SEEK_SET) < 0) {
270 fail_stop("Unable to seek.", NULL);
271 }
272 char zero = 0;
273 write_bytes(&zero, 1);
274 }
275 }
276 }
279 // Dump bytes to file -- at the current file position.
281 void FileMapInfo::write_bytes_aligned(const void* buffer, int nbytes) {
282 align_file_position();
283 write_bytes(buffer, nbytes);
284 align_file_position();
285 }
288 // Close the shared archive file. This does NOT unmap mapped regions.
290 void FileMapInfo::close() {
291 if (_file_open) {
292 if (::close(_fd) < 0) {
293 fail_stop("Unable to close the shared archive file.");
294 }
295 _file_open = false;
296 _fd = -1;
297 }
298 }
301 // JVM/TI RedefineClasses() support:
302 // Remap the shared readonly space to shared readwrite, private.
303 bool FileMapInfo::remap_shared_readonly_as_readwrite() {
304 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0];
305 if (!si->_read_only) {
306 // the space is already readwrite so we are done
307 return true;
308 }
309 size_t used = si->_used;
310 size_t size = align_size_up(used, os::vm_allocation_granularity());
311 if (!open_for_read()) {
312 return false;
313 }
314 char *base = os::remap_memory(_fd, _full_path, si->_file_offset,
315 si->_base, size, false /* !read_only */,
316 si->_allow_exec);
317 close();
318 if (base == NULL) {
319 fail_continue("Unable to remap shared readonly space (errno=%d).", errno);
320 return false;
321 }
322 if (base != si->_base) {
323 fail_continue("Unable to remap shared readonly space at required address.");
324 return false;
325 }
326 si->_read_only = false;
327 return true;
328 }
330 // Map the whole region at once, assumed to be allocated contiguously.
331 ReservedSpace FileMapInfo::reserve_shared_memory() {
332 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0];
333 char* requested_addr = si->_base;
334 size_t alignment = os::vm_allocation_granularity();
336 size_t size = align_size_up(SharedReadOnlySize + SharedReadWriteSize +
337 SharedMiscDataSize + SharedMiscCodeSize,
338 alignment);
340 // Reserve the space first, then map otherwise map will go right over some
341 // other reserved memory (like the code cache).
342 ReservedSpace rs(size, alignment, false, requested_addr);
343 if (!rs.is_reserved()) {
344 fail_continue(err_msg("Unable to reserved shared space at required address " INTPTR_FORMAT, requested_addr));
345 return rs;
346 }
347 return rs;
348 }
350 // Memory map a region in the address space.
352 char* FileMapInfo::map_region(int i, ReservedSpace rs) {
353 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
354 size_t used = si->_used;
355 size_t size = align_size_up(used, os::vm_allocation_granularity());
357 ReservedSpace mapped_rs = rs.first_part(size, true, true);
358 ReservedSpace unmapped_rs = rs.last_part(size);
359 mapped_rs.release();
361 return map_region(i);
362 }
365 // Memory map a region in the address space.
366 static const char* shared_region_name[] = { "ReadOnly", "ReadWrite", "MiscData", "MiscCode"};
368 char* FileMapInfo::map_region(int i) {
369 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
370 size_t used = si->_used;
371 size_t alignment = os::vm_allocation_granularity();
372 size_t size = align_size_up(used, alignment);
373 char *requested_addr = si->_base;
375 // map the contents of the CDS archive in this memory
376 char *base = os::map_memory(_fd, _full_path, si->_file_offset,
377 requested_addr, size, si->_read_only,
378 si->_allow_exec);
379 if (base == NULL || base != si->_base) {
380 fail_continue(err_msg("Unable to map %s shared space at required address.", shared_region_name[i]));
381 return NULL;
382 }
383 return base;
384 }
387 // Unmap a memory region in the address space.
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 }
399 void FileMapInfo::assert_mark(bool check) {
400 if (!check) {
401 fail_stop("Mark mismatch while restoring from shared file.", NULL);
402 }
403 }
406 FileMapInfo* FileMapInfo::_current_info = NULL;
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 bool FileMapInfo::initialize() {
414 assert(UseSharedSpaces, "UseSharedSpaces expected.");
416 if (JvmtiExport::can_modify_any_class() || JvmtiExport::can_walk_any_space()) {
417 fail_continue("Tool agent requires sharing to be disabled.");
418 return false;
419 }
421 if (!open_for_read()) {
422 return false;
423 }
425 init_from_file(_fd);
426 if (!validate()) {
427 return false;
428 }
430 SharedReadOnlySize = _header._space[0]._capacity;
431 SharedReadWriteSize = _header._space[1]._capacity;
432 SharedMiscDataSize = _header._space[2]._capacity;
433 SharedMiscCodeSize = _header._space[3]._capacity;
434 return true;
435 }
438 bool FileMapInfo::validate() {
439 if (_header._version != current_version()) {
440 fail_continue("The shared archive file is the wrong version.");
441 return false;
442 }
443 if (_header._magic != (int)0xf00baba2) {
444 fail_continue("The shared archive file has a bad magic number.");
445 return false;
446 }
447 if (strncmp(_header._jvm_ident, VM_Version::internal_vm_info_string(),
448 JVM_IDENT_MAX-1) != 0) {
449 fail_continue("The shared archive file was created by a different"
450 " version or build of HotSpot.");
451 return false;
452 }
454 // Cannot verify interpreter yet, as it can only be created after the GC
455 // heap has been initialized.
457 if (_header._num_jars >= JVM_SHARED_JARS_MAX) {
458 fail_continue("Too many jar files to share.");
459 return false;
460 }
462 // Build checks on classpath and jar files
463 int num_jars_now = 0;
464 ClassPathEntry *cpe = ClassLoader::classpath_entry(0);
465 for ( ; cpe != NULL; cpe = cpe->next()) {
467 if (cpe->is_jar_file()) {
468 if (num_jars_now < _header._num_jars) {
470 // Jar file - verify timestamp and file size.
471 struct stat st;
472 const char *path = cpe->name();
473 if (os::stat(path, &st) != 0) {
474 fail_continue("Unable to open jar file %s.", path);
475 return false;
476 }
477 if (_header._jar[num_jars_now]._timestamp != st.st_mtime ||
478 _header._jar[num_jars_now]._filesize != st.st_size) {
479 fail_continue("A jar file is not the one used while building"
480 " the shared archive file.");
481 return false;
482 }
483 }
484 ++num_jars_now;
485 } else {
487 // If directories appear in boot classpath, they must be empty to
488 // avoid having to verify each individual class file.
489 const char* name = ((ClassPathDirEntry*)cpe)->name();
490 if (!os::dir_is_empty(name)) {
491 fail_continue("Boot classpath directory %s is not empty.", name);
492 return false;
493 }
494 }
495 }
496 if (num_jars_now < _header._num_jars) {
497 fail_continue("The number of jar files in the boot classpath is"
498 " less than the number the shared archive was created with.");
499 return false;
500 }
502 return true;
503 }
505 // The following method is provided to see whether a given pointer
506 // falls in the mapped shared space.
507 // Param:
508 // p, The given pointer
509 // Return:
510 // True if the p is within the mapped shared space, otherwise, false.
511 bool FileMapInfo::is_in_shared_space(const void* p) {
512 for (int i = 0; i < MetaspaceShared::n_regions; i++) {
513 if (p >= _header._space[i]._base &&
514 p < _header._space[i]._base + _header._space[i]._used) {
515 return true;
516 }
517 }
519 return false;
520 }