Tue, 14 Jan 2014 16:40:33 +0100
8032379: Remove the is_scavenging flag to process_strong_roots
Summary: Refactor the strong root processing to avoid using a boolean in addition to the ScanOption enum.
Reviewed-by: stefank, tschatzl, ehelin, jmasa
1 /*
2 * Copyright (c) 2003, 2014, 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
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21 * questions.
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23 */
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"
36 # include <sys/stat.h>
37 # include <errno.h>
39 #ifndef O_BINARY // if defined (Win32) use binary files.
40 #define O_BINARY 0 // otherwise do nothing.
41 #endif
43 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
45 extern address JVM_FunctionAtStart();
46 extern address JVM_FunctionAtEnd();
48 // Complain and stop. All error conditions occurring during the writing of
49 // an archive file should stop the process. Unrecoverable errors during
50 // the reading of the archive file should stop the process.
52 static void fail(const char *msg, va_list ap) {
53 // This occurs very early during initialization: tty is not initialized.
54 jio_fprintf(defaultStream::error_stream(),
55 "An error has occurred while processing the"
56 " shared archive file.\n");
57 jio_vfprintf(defaultStream::error_stream(), msg, ap);
58 jio_fprintf(defaultStream::error_stream(), "\n");
59 // Do not change the text of the below message because some tests check for it.
60 vm_exit_during_initialization("Unable to use shared archive.", NULL);
61 }
64 void FileMapInfo::fail_stop(const char *msg, ...) {
65 va_list ap;
66 va_start(ap, msg);
67 fail(msg, ap); // Never returns.
68 va_end(ap); // for completeness.
69 }
72 // Complain and continue. Recoverable errors during the reading of the
73 // archive file may continue (with sharing disabled).
74 //
75 // If we continue, then disable shared spaces and close the file.
77 void FileMapInfo::fail_continue(const char *msg, ...) {
78 va_list ap;
79 va_start(ap, msg);
80 if (RequireSharedSpaces) {
81 fail(msg, ap);
82 }
83 va_end(ap);
84 UseSharedSpaces = false;
85 close();
86 }
88 // Fill in the fileMapInfo structure with data about this VM instance.
90 // This method copies the vm version info into header_version. If the version is too
91 // long then a truncated version, which has a hash code appended to it, is copied.
92 //
93 // Using a template enables this method to verify that header_version is an array of
94 // length JVM_IDENT_MAX. This ensures that the code that writes to the CDS file and
95 // the code that reads the CDS file will both use the same size buffer. Hence, will
96 // use identical truncation. This is necessary for matching of truncated versions.
97 template <int N> static void get_header_version(char (&header_version) [N]) {
98 assert(N == JVM_IDENT_MAX, "Bad header_version size");
100 const char *vm_version = VM_Version::internal_vm_info_string();
101 const int version_len = (int)strlen(vm_version);
103 if (version_len < (JVM_IDENT_MAX-1)) {
104 strcpy(header_version, vm_version);
106 } else {
107 // Get the hash value. Use a static seed because the hash needs to return the same
108 // value over multiple jvm invocations.
109 unsigned int hash = AltHashing::murmur3_32(8191, (const jbyte*)vm_version, version_len);
111 // Truncate the ident, saving room for the 8 hex character hash value.
112 strncpy(header_version, vm_version, JVM_IDENT_MAX-9);
114 // Append the hash code as eight hex digits.
115 sprintf(&header_version[JVM_IDENT_MAX-9], "%08x", hash);
116 header_version[JVM_IDENT_MAX-1] = 0; // Null terminate.
117 }
118 }
120 void FileMapInfo::populate_header(size_t alignment) {
121 _header._magic = 0xf00baba2;
122 _header._version = _current_version;
123 _header._alignment = alignment;
124 _header._obj_alignment = ObjectAlignmentInBytes;
126 // The following fields are for sanity checks for whether this archive
127 // will function correctly with this JVM and the bootclasspath it's
128 // invoked with.
130 // JVM version string ... changes on each build.
131 get_header_version(_header._jvm_ident);
133 // Build checks on classpath and jar files
134 _header._num_jars = 0;
135 ClassPathEntry *cpe = ClassLoader::classpath_entry(0);
136 for ( ; cpe != NULL; cpe = cpe->next()) {
138 if (cpe->is_jar_file()) {
139 if (_header._num_jars >= JVM_SHARED_JARS_MAX) {
140 fail_stop("Too many jar files to share.", NULL);
141 }
143 // Jar file - record timestamp and file size.
144 struct stat st;
145 const char *path = cpe->name();
146 if (os::stat(path, &st) != 0) {
147 // If we can't access a jar file in the boot path, then we can't
148 // make assumptions about where classes get loaded from.
149 fail_stop("Unable to open jar file %s.", path);
150 }
151 _header._jar[_header._num_jars]._timestamp = st.st_mtime;
152 _header._jar[_header._num_jars]._filesize = st.st_size;
153 _header._num_jars++;
154 } else {
156 // If directories appear in boot classpath, they must be empty to
157 // avoid having to verify each individual class file.
158 const char* name = ((ClassPathDirEntry*)cpe)->name();
159 if (!os::dir_is_empty(name)) {
160 fail_stop("Boot classpath directory %s is not empty.", name);
161 }
162 }
163 }
164 }
167 // Read the FileMapInfo information from the file.
169 bool FileMapInfo::init_from_file(int fd) {
171 size_t n = read(fd, &_header, sizeof(struct FileMapHeader));
172 if (n != sizeof(struct FileMapHeader)) {
173 fail_continue("Unable to read the file header.");
174 return false;
175 }
176 if (_header._version != current_version()) {
177 fail_continue("The shared archive file has the wrong version.");
178 return false;
179 }
180 _file_offset = (long)n;
181 return true;
182 }
185 // Read the FileMapInfo information from the file.
186 bool FileMapInfo::open_for_read() {
187 _full_path = Arguments::GetSharedArchivePath();
188 int fd = open(_full_path, O_RDONLY | O_BINARY, 0);
189 if (fd < 0) {
190 if (errno == ENOENT) {
191 // Not locating the shared archive is ok.
192 fail_continue("Specified shared archive not found.");
193 } else {
194 fail_continue("Failed to open shared archive file (%s).",
195 strerror(errno));
196 }
197 return false;
198 }
200 _fd = fd;
201 _file_open = true;
202 return true;
203 }
206 // Write the FileMapInfo information to the file.
208 void FileMapInfo::open_for_write() {
209 _full_path = Arguments::GetSharedArchivePath();
210 if (PrintSharedSpaces) {
211 tty->print_cr("Dumping shared data to file: ");
212 tty->print_cr(" %s", _full_path);
213 }
215 #ifdef _WINDOWS // On Windows, need WRITE permission to remove the file.
216 chmod(_full_path, _S_IREAD | _S_IWRITE);
217 #endif
219 // Use remove() to delete the existing file because, on Unix, this will
220 // allow processes that have it open continued access to the file.
221 remove(_full_path);
222 int fd = open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0444);
223 if (fd < 0) {
224 fail_stop("Unable to create shared archive file %s.", _full_path);
225 }
226 _fd = fd;
227 _file_offset = 0;
228 _file_open = true;
229 }
232 // Write the header to the file, seek to the next allocation boundary.
234 void FileMapInfo::write_header() {
235 write_bytes_aligned(&_header, sizeof(FileMapHeader));
236 }
239 // Dump shared spaces to file.
241 void FileMapInfo::write_space(int i, Metaspace* space, bool read_only) {
242 align_file_position();
243 size_t used = space->used_bytes_slow(Metaspace::NonClassType);
244 size_t capacity = space->capacity_bytes_slow(Metaspace::NonClassType);
245 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
246 write_region(i, (char*)space->bottom(), used, capacity, read_only, false);
247 }
250 // Dump region to file.
252 void FileMapInfo::write_region(int region, char* base, size_t size,
253 size_t capacity, bool read_only,
254 bool allow_exec) {
255 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[region];
257 if (_file_open) {
258 guarantee(si->_file_offset == _file_offset, "file offset mismatch.");
259 if (PrintSharedSpaces) {
260 tty->print_cr("Shared file region %d: 0x%6x bytes, addr " INTPTR_FORMAT
261 " file offset 0x%6x", region, size, base, _file_offset);
262 }
263 } else {
264 si->_file_offset = _file_offset;
265 }
266 si->_base = base;
267 si->_used = size;
268 si->_capacity = capacity;
269 si->_read_only = read_only;
270 si->_allow_exec = allow_exec;
271 write_bytes_aligned(base, (int)size);
272 }
275 // Dump bytes to file -- at the current file position.
277 void FileMapInfo::write_bytes(const void* buffer, int nbytes) {
278 if (_file_open) {
279 int n = ::write(_fd, buffer, nbytes);
280 if (n != nbytes) {
281 // It is dangerous to leave the corrupted shared archive file around,
282 // close and remove the file. See bug 6372906.
283 close();
284 remove(_full_path);
285 fail_stop("Unable to write to shared archive file.", NULL);
286 }
287 }
288 _file_offset += nbytes;
289 }
292 // Align file position to an allocation unit boundary.
294 void FileMapInfo::align_file_position() {
295 long new_file_offset = align_size_up(_file_offset, os::vm_allocation_granularity());
296 if (new_file_offset != _file_offset) {
297 _file_offset = new_file_offset;
298 if (_file_open) {
299 // Seek one byte back from the target and write a byte to insure
300 // that the written file is the correct length.
301 _file_offset -= 1;
302 if (lseek(_fd, _file_offset, SEEK_SET) < 0) {
303 fail_stop("Unable to seek.", NULL);
304 }
305 char zero = 0;
306 write_bytes(&zero, 1);
307 }
308 }
309 }
312 // Dump bytes to file -- at the current file position.
314 void FileMapInfo::write_bytes_aligned(const void* buffer, int nbytes) {
315 align_file_position();
316 write_bytes(buffer, nbytes);
317 align_file_position();
318 }
321 // Close the shared archive file. This does NOT unmap mapped regions.
323 void FileMapInfo::close() {
324 if (_file_open) {
325 if (::close(_fd) < 0) {
326 fail_stop("Unable to close the shared archive file.");
327 }
328 _file_open = false;
329 _fd = -1;
330 }
331 }
334 // JVM/TI RedefineClasses() support:
335 // Remap the shared readonly space to shared readwrite, private.
336 bool FileMapInfo::remap_shared_readonly_as_readwrite() {
337 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0];
338 if (!si->_read_only) {
339 // the space is already readwrite so we are done
340 return true;
341 }
342 size_t used = si->_used;
343 size_t size = align_size_up(used, os::vm_allocation_granularity());
344 if (!open_for_read()) {
345 return false;
346 }
347 char *base = os::remap_memory(_fd, _full_path, si->_file_offset,
348 si->_base, size, false /* !read_only */,
349 si->_allow_exec);
350 close();
351 if (base == NULL) {
352 fail_continue("Unable to remap shared readonly space (errno=%d).", errno);
353 return false;
354 }
355 if (base != si->_base) {
356 fail_continue("Unable to remap shared readonly space at required address.");
357 return false;
358 }
359 si->_read_only = false;
360 return true;
361 }
363 // Map the whole region at once, assumed to be allocated contiguously.
364 ReservedSpace FileMapInfo::reserve_shared_memory() {
365 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0];
366 char* requested_addr = si->_base;
368 size_t size = FileMapInfo::shared_spaces_size();
370 // Reserve the space first, then map otherwise map will go right over some
371 // other reserved memory (like the code cache).
372 ReservedSpace rs(size, os::vm_allocation_granularity(), false, requested_addr);
373 if (!rs.is_reserved()) {
374 fail_continue(err_msg("Unable to reserve shared space at required address " INTPTR_FORMAT, requested_addr));
375 return rs;
376 }
377 // the reserved virtual memory is for mapping class data sharing archive
378 MemTracker::record_virtual_memory_type((address)rs.base(), mtClassShared);
380 return rs;
381 }
383 // Memory map a region in the address space.
384 static const char* shared_region_name[] = { "ReadOnly", "ReadWrite", "MiscData", "MiscCode"};
386 char* FileMapInfo::map_region(int i) {
387 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
388 size_t used = si->_used;
389 size_t alignment = os::vm_allocation_granularity();
390 size_t size = align_size_up(used, alignment);
391 char *requested_addr = si->_base;
393 // map the contents of the CDS archive in this memory
394 char *base = os::map_memory(_fd, _full_path, si->_file_offset,
395 requested_addr, size, si->_read_only,
396 si->_allow_exec);
397 if (base == NULL || base != si->_base) {
398 fail_continue(err_msg("Unable to map %s shared space at required address.", shared_region_name[i]));
399 return NULL;
400 }
401 #ifdef _WINDOWS
402 // This call is Windows-only because the memory_type gets recorded for the other platforms
403 // in method FileMapInfo::reserve_shared_memory(), which is not called on Windows.
404 MemTracker::record_virtual_memory_type((address)base, mtClassShared);
405 #endif
406 return base;
407 }
410 // Unmap a memory region in the address space.
412 void FileMapInfo::unmap_region(int i) {
413 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
414 size_t used = si->_used;
415 size_t size = align_size_up(used, os::vm_allocation_granularity());
416 if (!os::unmap_memory(si->_base, size)) {
417 fail_stop("Unable to unmap shared space.");
418 }
419 }
422 void FileMapInfo::assert_mark(bool check) {
423 if (!check) {
424 fail_stop("Mark mismatch while restoring from shared file.", NULL);
425 }
426 }
429 FileMapInfo* FileMapInfo::_current_info = NULL;
432 // Open the shared archive file, read and validate the header
433 // information (version, boot classpath, etc.). If initialization
434 // fails, shared spaces are disabled and the file is closed. [See
435 // fail_continue.]
436 bool FileMapInfo::initialize() {
437 assert(UseSharedSpaces, "UseSharedSpaces expected.");
439 if (JvmtiExport::can_modify_any_class() || JvmtiExport::can_walk_any_space()) {
440 fail_continue("Tool agent requires sharing to be disabled.");
441 return false;
442 }
444 if (!open_for_read()) {
445 return false;
446 }
448 init_from_file(_fd);
449 if (!validate()) {
450 return false;
451 }
453 SharedReadOnlySize = _header._space[0]._capacity;
454 SharedReadWriteSize = _header._space[1]._capacity;
455 SharedMiscDataSize = _header._space[2]._capacity;
456 SharedMiscCodeSize = _header._space[3]._capacity;
457 return true;
458 }
461 bool FileMapInfo::validate() {
462 if (_header._version != current_version()) {
463 fail_continue("The shared archive file is the wrong version.");
464 return false;
465 }
466 if (_header._magic != (int)0xf00baba2) {
467 fail_continue("The shared archive file has a bad magic number.");
468 return false;
469 }
470 char header_version[JVM_IDENT_MAX];
471 get_header_version(header_version);
472 if (strncmp(_header._jvm_ident, header_version, JVM_IDENT_MAX-1) != 0) {
473 fail_continue("The shared archive file was created by a different"
474 " version or build of HotSpot.");
475 return false;
476 }
477 if (_header._obj_alignment != ObjectAlignmentInBytes) {
478 fail_continue("The shared archive file's ObjectAlignmentInBytes of %d"
479 " does not equal the current ObjectAlignmentInBytes of %d.",
480 _header._obj_alignment, ObjectAlignmentInBytes);
481 return false;
482 }
484 // Cannot verify interpreter yet, as it can only be created after the GC
485 // heap has been initialized.
487 if (_header._num_jars >= JVM_SHARED_JARS_MAX) {
488 fail_continue("Too many jar files to share.");
489 return false;
490 }
492 // Build checks on classpath and jar files
493 int num_jars_now = 0;
494 ClassPathEntry *cpe = ClassLoader::classpath_entry(0);
495 for ( ; cpe != NULL; cpe = cpe->next()) {
497 if (cpe->is_jar_file()) {
498 if (num_jars_now < _header._num_jars) {
500 // Jar file - verify timestamp and file size.
501 struct stat st;
502 const char *path = cpe->name();
503 if (os::stat(path, &st) != 0) {
504 fail_continue("Unable to open jar file %s.", path);
505 return false;
506 }
507 if (_header._jar[num_jars_now]._timestamp != st.st_mtime ||
508 _header._jar[num_jars_now]._filesize != st.st_size) {
509 fail_continue("A jar file is not the one used while building"
510 " the shared archive file.");
511 return false;
512 }
513 }
514 ++num_jars_now;
515 } else {
517 // If directories appear in boot classpath, they must be empty to
518 // avoid having to verify each individual class file.
519 const char* name = ((ClassPathDirEntry*)cpe)->name();
520 if (!os::dir_is_empty(name)) {
521 fail_continue("Boot classpath directory %s is not empty.", name);
522 return false;
523 }
524 }
525 }
526 if (num_jars_now < _header._num_jars) {
527 fail_continue("The number of jar files in the boot classpath is"
528 " less than the number the shared archive was created with.");
529 return false;
530 }
532 return true;
533 }
535 // The following method is provided to see whether a given pointer
536 // falls in the mapped shared space.
537 // Param:
538 // p, The given pointer
539 // Return:
540 // True if the p is within the mapped shared space, otherwise, false.
541 bool FileMapInfo::is_in_shared_space(const void* p) {
542 for (int i = 0; i < MetaspaceShared::n_regions; i++) {
543 if (p >= _header._space[i]._base &&
544 p < _header._space[i]._base + _header._space[i]._used) {
545 return true;
546 }
547 }
549 return false;
550 }
552 void FileMapInfo::print_shared_spaces() {
553 gclog_or_tty->print_cr("Shared Spaces:");
554 for (int i = 0; i < MetaspaceShared::n_regions; i++) {
555 struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
556 gclog_or_tty->print(" %s " INTPTR_FORMAT "-" INTPTR_FORMAT,
557 shared_region_name[i],
558 si->_base, si->_base + si->_used);
559 }
560 }
562 // Unmap mapped regions of shared space.
563 void FileMapInfo::stop_sharing_and_unmap(const char* msg) {
564 FileMapInfo *map_info = FileMapInfo::current_info();
565 if (map_info) {
566 map_info->fail_continue(msg);
567 for (int i = 0; i < MetaspaceShared::n_regions; i++) {
568 if (map_info->_header._space[i]._base != NULL) {
569 map_info->unmap_region(i);
570 map_info->_header._space[i]._base = NULL;
571 }
572 }
573 } else if (DumpSharedSpaces) {
574 fail_stop(msg, NULL);
575 }
576 }