1 /*
2 * Copyright (c) 2001, 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
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/vmSymbols.hpp"
27 #include "memory/allocation.inline.hpp"
28 #include "memory/resourceArea.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "os_windows.inline.hpp"
31 #include "runtime/handles.inline.hpp"
32 #include "runtime/perfMemory.hpp"
33 #include "services/memTracker.hpp"
34 #include "utilities/exceptions.hpp"
35
36 #include <windows.h>
37 #include <sys/types.h>
38 #include <sys/stat.h>
39 #include <errno.h>
40 #include <lmcons.h>
41
42 typedef BOOL (WINAPI *SetSecurityDescriptorControlFnPtr)(
43 IN PSECURITY_DESCRIPTOR pSecurityDescriptor,
44 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsOfInterest,
45 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsToSet);
46
47 // Standard Memory Implementation Details
48
49 // create the PerfData memory region in standard memory.
50 //
51 static char* create_standard_memory(size_t size) {
52
53 // allocate an aligned chuck of memory
54 char* mapAddress = os::reserve_memory(size);
55
56 if (mapAddress == NULL) {
57 return NULL;
58 }
59
60 // commit memory
61 if (!os::commit_memory(mapAddress, size, !ExecMem)) {
62 if (PrintMiscellaneous && Verbose) {
63 warning("Could not commit PerfData memory\n");
64 }
65 os::release_memory(mapAddress, size);
66 return NULL;
67 }
68
69 return mapAddress;
70 }
71
72 // delete the PerfData memory region
73 //
74 static void delete_standard_memory(char* addr, size_t size) {
75
76 // there are no persistent external resources to cleanup for standard
77 // memory. since DestroyJavaVM does not support unloading of the JVM,
78 // cleanup of the memory resource is not performed. The memory will be
79 // reclaimed by the OS upon termination of the process.
80 //
81 return;
82
83 }
84
85 // save the specified memory region to the given file
86 //
87 static void save_memory_to_file(char* addr, size_t size) {
88
89 const char* destfile = PerfMemory::get_perfdata_file_path();
90 assert(destfile[0] != '\0', "invalid Perfdata file path");
91
92 int fd = ::_open(destfile, _O_BINARY|_O_CREAT|_O_WRONLY|_O_TRUNC,
93 _S_IREAD|_S_IWRITE);
94
95 if (fd == OS_ERR) {
96 if (PrintMiscellaneous && Verbose) {
97 warning("Could not create Perfdata save file: %s: %s\n",
98 destfile, strerror(errno));
99 }
100 } else {
101 for (size_t remaining = size; remaining > 0;) {
102
103 int nbytes = ::_write(fd, addr, (unsigned int)remaining);
104 if (nbytes == OS_ERR) {
105 if (PrintMiscellaneous && Verbose) {
106 warning("Could not write Perfdata save file: %s: %s\n",
107 destfile, strerror(errno));
108 }
109 break;
110 }
111
112 remaining -= (size_t)nbytes;
113 addr += nbytes;
114 }
115
116 int result = ::_close(fd);
117 if (PrintMiscellaneous && Verbose) {
118 if (result == OS_ERR) {
119 warning("Could not close %s: %s\n", destfile, strerror(errno));
120 }
121 }
122 }
123
124 FREE_C_HEAP_ARRAY(char, destfile, mtInternal);
125 }
126
127 // Shared Memory Implementation Details
128
129 // Note: the win32 shared memory implementation uses two objects to represent
130 // the shared memory: a windows kernel based file mapping object and a backing
131 // store file. On windows, the name space for shared memory is a kernel
132 // based name space that is disjoint from other win32 name spaces. Since Java
133 // is unaware of this name space, a parallel file system based name space is
134 // maintained, which provides a common file system based shared memory name
135 // space across the supported platforms and one that Java apps can deal with
136 // through simple file apis.
137 //
138 // For performance and resource cleanup reasons, it is recommended that the
139 // user specific directory and the backing store file be stored in either a
140 // RAM based file system or a local disk based file system. Network based
141 // file systems are not recommended for performance reasons. In addition,
142 // use of SMB network based file systems may result in unsuccesful cleanup
143 // of the disk based resource on exit of the VM. The Windows TMP and TEMP
144 // environement variables, as used by the GetTempPath() Win32 API (see
145 // os::get_temp_directory() in os_win32.cpp), control the location of the
146 // user specific directory and the shared memory backing store file.
147
148 static HANDLE sharedmem_fileMapHandle = NULL;
149 static HANDLE sharedmem_fileHandle = INVALID_HANDLE_VALUE;
150 static char* sharedmem_fileName = NULL;
151
152 // return the user specific temporary directory name.
153 //
154 // the caller is expected to free the allocated memory.
155 //
156 static char* get_user_tmp_dir(const char* user) {
157
158 const char* tmpdir = os::get_temp_directory();
159 const char* perfdir = PERFDATA_NAME;
160 size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
161 char* dirname = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
162
163 // construct the path name to user specific tmp directory
164 _snprintf(dirname, nbytes, "%s\\%s_%s", tmpdir, perfdir, user);
165
166 return dirname;
167 }
168
169 // convert the given file name into a process id. if the file
170 // does not meet the file naming constraints, return 0.
171 //
172 static int filename_to_pid(const char* filename) {
173
174 // a filename that doesn't begin with a digit is not a
175 // candidate for conversion.
176 //
177 if (!isdigit(*filename)) {
178 return 0;
179 }
180
181 // check if file name can be converted to an integer without
182 // any leftover characters.
183 //
184 char* remainder = NULL;
185 errno = 0;
186 int pid = (int)strtol(filename, &remainder, 10);
187
188 if (errno != 0) {
189 return 0;
190 }
191
192 // check for left over characters. If any, then the filename is
193 // not a candidate for conversion.
194 //
195 if (remainder != NULL && *remainder != '\0') {
196 return 0;
197 }
198
199 // successful conversion, return the pid
200 return pid;
201 }
202
203 // check if the given path is considered a secure directory for
204 // the backing store files. Returns true if the directory exists
205 // and is considered a secure location. Returns false if the path
206 // is a symbolic link or if an error occurred.
207 //
208 static bool is_directory_secure(const char* path) {
209
210 DWORD fa;
211
212 fa = GetFileAttributes(path);
213 if (fa == 0xFFFFFFFF) {
214 DWORD lasterror = GetLastError();
215 if (lasterror == ERROR_FILE_NOT_FOUND) {
216 return false;
217 }
218 else {
219 // unexpected error, declare the path insecure
220 if (PrintMiscellaneous && Verbose) {
221 warning("could not get attributes for file %s: ",
222 " lasterror = %d\n", path, lasterror);
223 }
224 return false;
225 }
226 }
227
228 if (fa & FILE_ATTRIBUTE_REPARSE_POINT) {
229 // we don't accept any redirection for the user specific directory
230 // so declare the path insecure. This may be too conservative,
231 // as some types of reparse points might be acceptable, but it
232 // is probably more secure to avoid these conditions.
233 //
234 if (PrintMiscellaneous && Verbose) {
235 warning("%s is a reparse point\n", path);
236 }
237 return false;
238 }
239
240 if (fa & FILE_ATTRIBUTE_DIRECTORY) {
241 // this is the expected case. Since windows supports symbolic
242 // links to directories only, not to files, there is no need
243 // to check for open write permissions on the directory. If the
244 // directory has open write permissions, any files deposited that
245 // are not expected will be removed by the cleanup code.
246 //
247 return true;
248 }
249 else {
250 // this is either a regular file or some other type of file,
251 // any of which are unexpected and therefore insecure.
252 //
253 if (PrintMiscellaneous && Verbose) {
254 warning("%s is not a directory, file attributes = "
255 INTPTR_FORMAT "\n", path, fa);
256 }
257 return false;
258 }
259 }
260
261 // return the user name for the owner of this process
262 //
263 // the caller is expected to free the allocated memory.
264 //
265 static char* get_user_name() {
266
267 /* get the user name. This code is adapted from code found in
268 * the jdk in src/windows/native/java/lang/java_props_md.c
269 * java_props_md.c 1.29 02/02/06. According to the original
270 * source, the call to GetUserName is avoided because of a resulting
271 * increase in footprint of 100K.
272 */
273 char* user = getenv("USERNAME");
274 char buf[UNLEN+1];
275 DWORD buflen = sizeof(buf);
276 if (user == NULL || strlen(user) == 0) {
277 if (GetUserName(buf, &buflen)) {
278 user = buf;
279 }
280 else {
281 return NULL;
282 }
283 }
284
285 char* user_name = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
286 strcpy(user_name, user);
287
288 return user_name;
289 }
290
291 // return the name of the user that owns the process identified by vmid.
292 //
293 // This method uses a slow directory search algorithm to find the backing
294 // store file for the specified vmid and returns the user name, as determined
295 // by the user name suffix of the hsperfdata_<username> directory name.
296 //
297 // the caller is expected to free the allocated memory.
298 //
299 static char* get_user_name_slow(int vmid) {
300
301 // directory search
302 char* latest_user = NULL;
303 time_t latest_ctime = 0;
304
305 const char* tmpdirname = os::get_temp_directory();
306
307 DIR* tmpdirp = os::opendir(tmpdirname);
308
309 if (tmpdirp == NULL) {
310 return NULL;
311 }
312
313 // for each entry in the directory that matches the pattern hsperfdata_*,
314 // open the directory and check if the file for the given vmid exists.
315 // The file with the expected name and the latest creation date is used
316 // to determine the user name for the process id.
317 //
318 struct dirent* dentry;
319 errno = 0;
320 while ((dentry = os::readdir(tmpdirp)) != NULL) {
321
322 // check if the directory entry is a hsperfdata file
323 if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
324 continue;
325 }
326
327 char* usrdir_name = NEW_C_HEAP_ARRAY(char,
328 strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal);
329 strcpy(usrdir_name, tmpdirname);
330 strcat(usrdir_name, "\\");
331 strcat(usrdir_name, dentry->d_name);
332
333 DIR* subdirp = os::opendir(usrdir_name);
334
335 if (subdirp == NULL) {
336 FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
337 continue;
338 }
339
340 // Since we don't create the backing store files in directories
341 // pointed to by symbolic links, we also don't follow them when
342 // looking for the files. We check for a symbolic link after the
343 // call to opendir in order to eliminate a small window where the
344 // symlink can be exploited.
345 //
346 if (!is_directory_secure(usrdir_name)) {
347 FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
348 os::closedir(subdirp);
349 continue;
350 }
351
352 struct dirent* udentry;
353 errno = 0;
354 while ((udentry = os::readdir(subdirp)) != NULL) {
355
356 if (filename_to_pid(udentry->d_name) == vmid) {
357 struct stat statbuf;
358
359 char* filename = NEW_C_HEAP_ARRAY(char,
360 strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal);
361
362 strcpy(filename, usrdir_name);
363 strcat(filename, "\\");
364 strcat(filename, udentry->d_name);
365
366 if (::stat(filename, &statbuf) == OS_ERR) {
367 FREE_C_HEAP_ARRAY(char, filename, mtInternal);
368 continue;
369 }
370
371 // skip over files that are not regular files.
372 if ((statbuf.st_mode & S_IFMT) != S_IFREG) {
373 FREE_C_HEAP_ARRAY(char, filename, mtInternal);
374 continue;
375 }
376
377 // If we found a matching file with a newer creation time, then
378 // save the user name. The newer creation time indicates that
379 // we found a newer incarnation of the process associated with
380 // vmid. Due to the way that Windows recycles pids and the fact
381 // that we can't delete the file from the file system namespace
382 // until last close, it is possible for there to be more than
383 // one hsperfdata file with a name matching vmid (diff users).
384 //
385 // We no longer ignore hsperfdata files where (st_size == 0).
386 // In this function, all we're trying to do is determine the
387 // name of the user that owns the process associated with vmid
388 // so the size doesn't matter. Very rarely, we have observed
389 // hsperfdata files where (st_size == 0) and the st_size field
390 // later becomes the expected value.
391 //
392 if (statbuf.st_ctime > latest_ctime) {
393 char* user = strchr(dentry->d_name, '_') + 1;
394
395 if (latest_user != NULL) FREE_C_HEAP_ARRAY(char, latest_user, mtInternal);
396 latest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
397
398 strcpy(latest_user, user);
399 latest_ctime = statbuf.st_ctime;
400 }
401
402 FREE_C_HEAP_ARRAY(char, filename, mtInternal);
403 }
404 }
405 os::closedir(subdirp);
406 FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
407 }
408 os::closedir(tmpdirp);
409
410 return(latest_user);
411 }
412
413 // return the name of the user that owns the process identified by vmid.
414 //
415 // note: this method should only be used via the Perf native methods.
416 // There are various costs to this method and limiting its use to the
417 // Perf native methods limits the impact to monitoring applications only.
418 //
419 static char* get_user_name(int vmid) {
420
421 // A fast implementation is not provided at this time. It's possible
422 // to provide a fast process id to user name mapping function using
423 // the win32 apis, but the default ACL for the process object only
424 // allows processes with the same owner SID to acquire the process
425 // handle (via OpenProcess(PROCESS_QUERY_INFORMATION)). It's possible
426 // to have the JVM change the ACL for the process object to allow arbitrary
427 // users to access the process handle and the process security token.
428 // The security ramifications need to be studied before providing this
429 // mechanism.
430 //
431 return get_user_name_slow(vmid);
432 }
433
434 // return the name of the shared memory file mapping object for the
435 // named shared memory region for the given user name and vmid.
436 //
437 // The file mapping object's name is not the file name. It is a name
438 // in a separate name space.
439 //
440 // the caller is expected to free the allocated memory.
441 //
442 static char *get_sharedmem_objectname(const char* user, int vmid) {
443
444 // construct file mapping object's name, add 3 for two '_' and a
445 // null terminator.
446 int nbytes = (int)strlen(PERFDATA_NAME) + (int)strlen(user) + 3;
447
448 // the id is converted to an unsigned value here because win32 allows
449 // negative process ids. However, OpenFileMapping API complains
450 // about a name containing a '-' characters.
451 //
452 nbytes += UINT_CHARS;
453 char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
454 _snprintf(name, nbytes, "%s_%s_%u", PERFDATA_NAME, user, vmid);
455
456 return name;
457 }
458
459 // return the file name of the backing store file for the named
460 // shared memory region for the given user name and vmid.
461 //
462 // the caller is expected to free the allocated memory.
463 //
464 static char* get_sharedmem_filename(const char* dirname, int vmid) {
465
466 // add 2 for the file separator and a null terminator.
467 size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
468
469 char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
470 _snprintf(name, nbytes, "%s\\%d", dirname, vmid);
471
472 return name;
473 }
474
475 // remove file
476 //
477 // this method removes the file with the given file name.
478 //
479 // Note: if the indicated file is on an SMB network file system, this
480 // method may be unsuccessful in removing the file.
481 //
482 static void remove_file(const char* dirname, const char* filename) {
483
484 size_t nbytes = strlen(dirname) + strlen(filename) + 2;
485 char* path = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
486
487 strcpy(path, dirname);
488 strcat(path, "\\");
489 strcat(path, filename);
490
491 if (::unlink(path) == OS_ERR) {
492 if (PrintMiscellaneous && Verbose) {
493 if (errno != ENOENT) {
494 warning("Could not unlink shared memory backing"
495 " store file %s : %s\n", path, strerror(errno));
496 }
497 }
498 }
499
500 FREE_C_HEAP_ARRAY(char, path, mtInternal);
501 }
502
503 // returns true if the process represented by pid is alive, otherwise
504 // returns false. the validity of the result is only accurate if the
505 // target process is owned by the same principal that owns this process.
506 // this method should not be used if to test the status of an otherwise
507 // arbitrary process unless it is know that this process has the appropriate
508 // privileges to guarantee a result valid.
509 //
510 static bool is_alive(int pid) {
511
512 HANDLE ph = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);
513 if (ph == NULL) {
514 // the process does not exist.
515 if (PrintMiscellaneous && Verbose) {
516 DWORD lastError = GetLastError();
517 if (lastError != ERROR_INVALID_PARAMETER) {
518 warning("OpenProcess failed: %d\n", GetLastError());
519 }
520 }
521 return false;
522 }
523
524 DWORD exit_status;
525 if (!GetExitCodeProcess(ph, &exit_status)) {
526 if (PrintMiscellaneous && Verbose) {
527 warning("GetExitCodeProcess failed: %d\n", GetLastError());
528 }
529 CloseHandle(ph);
530 return false;
531 }
532
533 CloseHandle(ph);
534 return (exit_status == STILL_ACTIVE) ? true : false;
535 }
536
537 // check if the file system is considered secure for the backing store files
538 //
539 static bool is_filesystem_secure(const char* path) {
540
541 char root_path[MAX_PATH];
542 char fs_type[MAX_PATH];
543
544 if (PerfBypassFileSystemCheck) {
545 if (PrintMiscellaneous && Verbose) {
546 warning("bypassing file system criteria checks for %s\n", path);
547 }
548 return true;
549 }
550
551 char* first_colon = strchr((char *)path, ':');
552 if (first_colon == NULL) {
553 if (PrintMiscellaneous && Verbose) {
554 warning("expected device specifier in path: %s\n", path);
555 }
556 return false;
557 }
558
559 size_t len = (size_t)(first_colon - path);
560 assert(len + 2 <= MAX_PATH, "unexpected device specifier length");
561 strncpy(root_path, path, len + 1);
562 root_path[len + 1] = '\\';
563 root_path[len + 2] = '\0';
564
565 // check that we have something like "C:\" or "AA:\"
566 assert(strlen(root_path) >= 3, "device specifier too short");
567 assert(strchr(root_path, ':') != NULL, "bad device specifier format");
568 assert(strchr(root_path, '\\') != NULL, "bad device specifier format");
569
570 DWORD maxpath;
571 DWORD flags;
572
573 if (!GetVolumeInformation(root_path, NULL, 0, NULL, &maxpath,
574 &flags, fs_type, MAX_PATH)) {
575 // we can't get information about the volume, so assume unsafe.
576 if (PrintMiscellaneous && Verbose) {
577 warning("could not get device information for %s: "
578 " path = %s: lasterror = %d\n",
579 root_path, path, GetLastError());
580 }
581 return false;
582 }
583
584 if ((flags & FS_PERSISTENT_ACLS) == 0) {
585 // file system doesn't support ACLs, declare file system unsafe
586 if (PrintMiscellaneous && Verbose) {
587 warning("file system type %s on device %s does not support"
588 " ACLs\n", fs_type, root_path);
589 }
590 return false;
591 }
592
593 if ((flags & FS_VOL_IS_COMPRESSED) != 0) {
594 // file system is compressed, declare file system unsafe
595 if (PrintMiscellaneous && Verbose) {
596 warning("file system type %s on device %s is compressed\n",
597 fs_type, root_path);
598 }
599 return false;
600 }
601
602 return true;
603 }
604
605 // cleanup stale shared memory resources
606 //
607 // This method attempts to remove all stale shared memory files in
608 // the named user temporary directory. It scans the named directory
609 // for files matching the pattern ^$[0-9]*$. For each file found, the
610 // process id is extracted from the file name and a test is run to
611 // determine if the process is alive. If the process is not alive,
612 // any stale file resources are removed.
613 //
614 static void cleanup_sharedmem_resources(const char* dirname) {
615
616 // open the user temp directory
617 DIR* dirp = os::opendir(dirname);
618
619 if (dirp == NULL) {
620 // directory doesn't exist, so there is nothing to cleanup
621 return;
622 }
623
624 if (!is_directory_secure(dirname)) {
625 // the directory is not secure, don't attempt any cleanup
626 return;
627 }
628
629 // for each entry in the directory that matches the expected file
630 // name pattern, determine if the file resources are stale and if
631 // so, remove the file resources. Note, instrumented HotSpot processes
632 // for this user may start and/or terminate during this search and
633 // remove or create new files in this directory. The behavior of this
634 // loop under these conditions is dependent upon the implementation of
635 // opendir/readdir.
636 //
637 struct dirent* entry;
638 errno = 0;
639 while ((entry = os::readdir(dirp)) != NULL) {
640
641 int pid = filename_to_pid(entry->d_name);
642
643 if (pid == 0) {
644
645 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
646
647 // attempt to remove all unexpected files, except "." and ".."
648 remove_file(dirname, entry->d_name);
649 }
650
651 errno = 0;
652 continue;
653 }
654
655 // we now have a file name that converts to a valid integer
656 // that could represent a process id . if this process id
657 // matches the current process id or the process is not running,
658 // then remove the stale file resources.
659 //
660 // process liveness is detected by checking the exit status
661 // of the process. if the process id is valid and the exit status
662 // indicates that it is still running, the file file resources
663 // are not removed. If the process id is invalid, or if we don't
664 // have permissions to check the process status, or if the process
665 // id is valid and the process has terminated, the the file resources
666 // are assumed to be stale and are removed.
667 //
668 if (pid == os::current_process_id() || !is_alive(pid)) {
669
670 // we can only remove the file resources. Any mapped views
671 // of the file can only be unmapped by the processes that
672 // opened those views and the file mapping object will not
673 // get removed until all views are unmapped.
674 //
675 remove_file(dirname, entry->d_name);
676 }
677 errno = 0;
678 }
679 os::closedir(dirp);
680 }
681
682 // create a file mapping object with the requested name, and size
683 // from the file represented by the given Handle object
684 //
685 static HANDLE create_file_mapping(const char* name, HANDLE fh, LPSECURITY_ATTRIBUTES fsa, size_t size) {
686
687 DWORD lowSize = (DWORD)size;
688 DWORD highSize = 0;
689 HANDLE fmh = NULL;
690
691 // Create a file mapping object with the given name. This function
692 // will grow the file to the specified size.
693 //
694 fmh = CreateFileMapping(
695 fh, /* HANDLE file handle for backing store */
696 fsa, /* LPSECURITY_ATTRIBUTES Not inheritable */
697 PAGE_READWRITE, /* DWORD protections */
698 highSize, /* DWORD High word of max size */
699 lowSize, /* DWORD Low word of max size */
700 name); /* LPCTSTR name for object */
701
702 if (fmh == NULL) {
703 if (PrintMiscellaneous && Verbose) {
704 warning("CreateFileMapping failed, lasterror = %d\n", GetLastError());
705 }
706 return NULL;
707 }
708
709 if (GetLastError() == ERROR_ALREADY_EXISTS) {
710
711 // a stale file mapping object was encountered. This object may be
712 // owned by this or some other user and cannot be removed until
713 // the other processes either exit or close their mapping objects
714 // and/or mapped views of this mapping object.
715 //
716 if (PrintMiscellaneous && Verbose) {
717 warning("file mapping already exists, lasterror = %d\n", GetLastError());
718 }
719
720 CloseHandle(fmh);
721 return NULL;
722 }
723
724 return fmh;
725 }
726
727
728 // method to free the given security descriptor and the contained
729 // access control list.
730 //
731 static void free_security_desc(PSECURITY_DESCRIPTOR pSD) {
732
733 BOOL success, exists, isdefault;
734 PACL pACL;
735
736 if (pSD != NULL) {
737
738 // get the access control list from the security descriptor
739 success = GetSecurityDescriptorDacl(pSD, &exists, &pACL, &isdefault);
740
741 // if an ACL existed and it was not a default acl, then it must
742 // be an ACL we enlisted. free the resources.
743 //
744 if (success && exists && pACL != NULL && !isdefault) {
745 FREE_C_HEAP_ARRAY(char, pACL, mtInternal);
746 }
747
748 // free the security descriptor
749 FREE_C_HEAP_ARRAY(char, pSD, mtInternal);
750 }
751 }
752
753 // method to free up a security attributes structure and any
754 // contained security descriptors and ACL
755 //
756 static void free_security_attr(LPSECURITY_ATTRIBUTES lpSA) {
757
758 if (lpSA != NULL) {
759 // free the contained security descriptor and the ACL
760 free_security_desc(lpSA->lpSecurityDescriptor);
761 lpSA->lpSecurityDescriptor = NULL;
762
763 // free the security attributes structure
764 FREE_C_HEAP_ARRAY(char, lpSA, mtInternal);
765 }
766 }
767
768 // get the user SID for the process indicated by the process handle
769 //
770 static PSID get_user_sid(HANDLE hProcess) {
771
772 HANDLE hAccessToken;
773 PTOKEN_USER token_buf = NULL;
774 DWORD rsize = 0;
775
776 if (hProcess == NULL) {
777 return NULL;
778 }
779
780 // get the process token
781 if (!OpenProcessToken(hProcess, TOKEN_READ, &hAccessToken)) {
782 if (PrintMiscellaneous && Verbose) {
783 warning("OpenProcessToken failure: lasterror = %d \n", GetLastError());
784 }
785 return NULL;
786 }
787
788 // determine the size of the token structured needed to retrieve
789 // the user token information from the access token.
790 //
791 if (!GetTokenInformation(hAccessToken, TokenUser, NULL, rsize, &rsize)) {
792 DWORD lasterror = GetLastError();
793 if (lasterror != ERROR_INSUFFICIENT_BUFFER) {
794 if (PrintMiscellaneous && Verbose) {
795 warning("GetTokenInformation failure: lasterror = %d,"
796 " rsize = %d\n", lasterror, rsize);
797 }
798 CloseHandle(hAccessToken);
799 return NULL;
800 }
801 }
802
803 token_buf = (PTOKEN_USER) NEW_C_HEAP_ARRAY(char, rsize, mtInternal);
804
805 // get the user token information
806 if (!GetTokenInformation(hAccessToken, TokenUser, token_buf, rsize, &rsize)) {
807 if (PrintMiscellaneous && Verbose) {
808 warning("GetTokenInformation failure: lasterror = %d,"
809 " rsize = %d\n", GetLastError(), rsize);
810 }
811 FREE_C_HEAP_ARRAY(char, token_buf, mtInternal);
812 CloseHandle(hAccessToken);
813 return NULL;
814 }
815
816 DWORD nbytes = GetLengthSid(token_buf->User.Sid);
817 PSID pSID = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
818
819 if (!CopySid(nbytes, pSID, token_buf->User.Sid)) {
820 if (PrintMiscellaneous && Verbose) {
821 warning("GetTokenInformation failure: lasterror = %d,"
822 " rsize = %d\n", GetLastError(), rsize);
823 }
824 FREE_C_HEAP_ARRAY(char, token_buf, mtInternal);
825 FREE_C_HEAP_ARRAY(char, pSID, mtInternal);
826 CloseHandle(hAccessToken);
827 return NULL;
828 }
829
830 // close the access token.
831 CloseHandle(hAccessToken);
832 FREE_C_HEAP_ARRAY(char, token_buf, mtInternal);
833
834 return pSID;
835 }
836
837 // structure used to consolidate access control entry information
838 //
839 typedef struct ace_data {
840 PSID pSid; // SID of the ACE
841 DWORD mask; // mask for the ACE
842 } ace_data_t;
843
844
845 // method to add an allow access control entry with the access rights
846 // indicated in mask for the principal indicated in SID to the given
847 // security descriptor. Much of the DACL handling was adapted from
848 // the example provided here:
849 // http://support.microsoft.com/kb/102102/EN-US/
850 //
851
852 static bool add_allow_aces(PSECURITY_DESCRIPTOR pSD,
853 ace_data_t aces[], int ace_count) {
854 PACL newACL = NULL;
855 PACL oldACL = NULL;
856
857 if (pSD == NULL) {
858 return false;
859 }
860
861 BOOL exists, isdefault;
862
863 // retrieve any existing access control list.
864 if (!GetSecurityDescriptorDacl(pSD, &exists, &oldACL, &isdefault)) {
865 if (PrintMiscellaneous && Verbose) {
866 warning("GetSecurityDescriptor failure: lasterror = %d \n",
867 GetLastError());
868 }
869 return false;
870 }
871
872 // get the size of the DACL
873 ACL_SIZE_INFORMATION aclinfo;
874
875 // GetSecurityDescriptorDacl may return true value for exists (lpbDaclPresent)
876 // while oldACL is NULL for some case.
877 if (oldACL == NULL) {
878 exists = FALSE;
879 }
880
881 if (exists) {
882 if (!GetAclInformation(oldACL, &aclinfo,
883 sizeof(ACL_SIZE_INFORMATION),
884 AclSizeInformation)) {
885 if (PrintMiscellaneous && Verbose) {
886 warning("GetAclInformation failure: lasterror = %d \n", GetLastError());
887 return false;
888 }
889 }
890 } else {
891 aclinfo.AceCount = 0; // assume NULL DACL
892 aclinfo.AclBytesFree = 0;
893 aclinfo.AclBytesInUse = sizeof(ACL);
894 }
895
896 // compute the size needed for the new ACL
897 // initial size of ACL is sum of the following:
898 // * size of ACL structure.
899 // * size of each ACE structure that ACL is to contain minus the sid
900 // sidStart member (DWORD) of the ACE.
901 // * length of the SID that each ACE is to contain.
902 DWORD newACLsize = aclinfo.AclBytesInUse +
903 (sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD)) * ace_count;
904 for (int i = 0; i < ace_count; i++) {
905 assert(aces[i].pSid != 0, "pSid should not be 0");
906 newACLsize += GetLengthSid(aces[i].pSid);
907 }
908
909 // create the new ACL
910 newACL = (PACL) NEW_C_HEAP_ARRAY(char, newACLsize, mtInternal);
911
912 if (!InitializeAcl(newACL, newACLsize, ACL_REVISION)) {
913 if (PrintMiscellaneous && Verbose) {
914 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
915 }
916 FREE_C_HEAP_ARRAY(char, newACL, mtInternal);
917 return false;
918 }
919
920 unsigned int ace_index = 0;
921 // copy any existing ACEs from the old ACL (if any) to the new ACL.
922 if (aclinfo.AceCount != 0) {
923 while (ace_index < aclinfo.AceCount) {
924 LPVOID ace;
925 if (!GetAce(oldACL, ace_index, &ace)) {
926 if (PrintMiscellaneous && Verbose) {
927 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
928 }
929 FREE_C_HEAP_ARRAY(char, newACL, mtInternal);
930 return false;
931 }
932 if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceFlags && INHERITED_ACE) {
933 // this is an inherited, allowed ACE; break from loop so we can
934 // add the new access allowed, non-inherited ACE in the correct
935 // position, immediately following all non-inherited ACEs.
936 break;
937 }
938
939 // determine if the SID of this ACE matches any of the SIDs
940 // for which we plan to set ACEs.
941 int matches = 0;
942 for (int i = 0; i < ace_count; i++) {
943 if (EqualSid(aces[i].pSid, &(((ACCESS_ALLOWED_ACE *)ace)->SidStart))) {
944 matches++;
945 break;
946 }
947 }
948
949 // if there are no SID matches, then add this existing ACE to the new ACL
950 if (matches == 0) {
951 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
952 ((PACE_HEADER)ace)->AceSize)) {
953 if (PrintMiscellaneous && Verbose) {
954 warning("AddAce failure: lasterror = %d \n", GetLastError());
955 }
956 FREE_C_HEAP_ARRAY(char, newACL, mtInternal);
957 return false;
958 }
959 }
960 ace_index++;
961 }
962 }
963
964 // add the passed-in access control entries to the new ACL
965 for (int i = 0; i < ace_count; i++) {
966 if (!AddAccessAllowedAce(newACL, ACL_REVISION,
967 aces[i].mask, aces[i].pSid)) {
968 if (PrintMiscellaneous && Verbose) {
969 warning("AddAccessAllowedAce failure: lasterror = %d \n",
970 GetLastError());
971 }
972 FREE_C_HEAP_ARRAY(char, newACL, mtInternal);
973 return false;
974 }
975 }
976
977 // now copy the rest of the inherited ACEs from the old ACL
978 if (aclinfo.AceCount != 0) {
979 // picking up at ace_index, where we left off in the
980 // previous ace_index loop
981 while (ace_index < aclinfo.AceCount) {
982 LPVOID ace;
983 if (!GetAce(oldACL, ace_index, &ace)) {
984 if (PrintMiscellaneous && Verbose) {
985 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
986 }
987 FREE_C_HEAP_ARRAY(char, newACL, mtInternal);
988 return false;
989 }
990 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
991 ((PACE_HEADER)ace)->AceSize)) {
992 if (PrintMiscellaneous && Verbose) {
993 warning("AddAce failure: lasterror = %d \n", GetLastError());
994 }
995 FREE_C_HEAP_ARRAY(char, newACL, mtInternal);
996 return false;
997 }
998 ace_index++;
999 }
1000 }
1001
1002 // add the new ACL to the security descriptor.
1003 if (!SetSecurityDescriptorDacl(pSD, TRUE, newACL, FALSE)) {
1004 if (PrintMiscellaneous && Verbose) {
1005 warning("SetSecurityDescriptorDacl failure:"
1006 " lasterror = %d \n", GetLastError());
1007 }
1008 FREE_C_HEAP_ARRAY(char, newACL, mtInternal);
1009 return false;
1010 }
1011
1012 // if running on windows 2000 or later, set the automatic inheritance
1013 // control flags.
1014 SetSecurityDescriptorControlFnPtr _SetSecurityDescriptorControl;
1015 _SetSecurityDescriptorControl = (SetSecurityDescriptorControlFnPtr)
1016 GetProcAddress(GetModuleHandle(TEXT("advapi32.dll")),
1017 "SetSecurityDescriptorControl");
1018
1019 if (_SetSecurityDescriptorControl != NULL) {
1020 // We do not want to further propagate inherited DACLs, so making them
1021 // protected prevents that.
1022 if (!_SetSecurityDescriptorControl(pSD, SE_DACL_PROTECTED,
1023 SE_DACL_PROTECTED)) {
1024 if (PrintMiscellaneous && Verbose) {
1025 warning("SetSecurityDescriptorControl failure:"
1026 " lasterror = %d \n", GetLastError());
1027 }
1028 FREE_C_HEAP_ARRAY(char, newACL, mtInternal);
1029 return false;
1030 }
1031 }
1032 // Note, the security descriptor maintains a reference to the newACL, not
1033 // a copy of it. Therefore, the newACL is not freed here. It is freed when
1034 // the security descriptor containing its reference is freed.
1035 //
1036 return true;
1037 }
1038
1039 // method to create a security attributes structure, which contains a
1040 // security descriptor and an access control list comprised of 0 or more
1041 // access control entries. The method take an array of ace_data structures
1042 // that indicate the ACE to be added to the security descriptor.
1043 //
1044 // the caller must free the resources associated with the security
1045 // attributes structure created by this method by calling the
1046 // free_security_attr() method.
1047 //
1048 static LPSECURITY_ATTRIBUTES make_security_attr(ace_data_t aces[], int count) {
1049
1050 // allocate space for a security descriptor
1051 PSECURITY_DESCRIPTOR pSD = (PSECURITY_DESCRIPTOR)
1052 NEW_C_HEAP_ARRAY(char, SECURITY_DESCRIPTOR_MIN_LENGTH, mtInternal);
1053
1054 // initialize the security descriptor
1055 if (!InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION)) {
1056 if (PrintMiscellaneous && Verbose) {
1057 warning("InitializeSecurityDescriptor failure: "
1058 "lasterror = %d \n", GetLastError());
1059 }
1060 free_security_desc(pSD);
1061 return NULL;
1062 }
1063
1064 // add the access control entries
1065 if (!add_allow_aces(pSD, aces, count)) {
1066 free_security_desc(pSD);
1067 return NULL;
1068 }
1069
1070 // allocate and initialize the security attributes structure and
1071 // return it to the caller.
1072 //
1073 LPSECURITY_ATTRIBUTES lpSA = (LPSECURITY_ATTRIBUTES)
1074 NEW_C_HEAP_ARRAY(char, sizeof(SECURITY_ATTRIBUTES), mtInternal);
1075 lpSA->nLength = sizeof(SECURITY_ATTRIBUTES);
1076 lpSA->lpSecurityDescriptor = pSD;
1077 lpSA->bInheritHandle = FALSE;
1078
1079 return(lpSA);
1080 }
1081
1082 // method to create a security attributes structure with a restrictive
1083 // access control list that creates a set access rights for the user/owner
1084 // of the securable object and a separate set access rights for everyone else.
1085 // also provides for full access rights for the administrator group.
1086 //
1087 // the caller must free the resources associated with the security
1088 // attributes structure created by this method by calling the
1089 // free_security_attr() method.
1090 //
1091
1092 static LPSECURITY_ATTRIBUTES make_user_everybody_admin_security_attr(
1093 DWORD umask, DWORD emask, DWORD amask) {
1094
1095 ace_data_t aces[3];
1096
1097 // initialize the user ace data
1098 aces[0].pSid = get_user_sid(GetCurrentProcess());
1099 aces[0].mask = umask;
1100
1101 if (aces[0].pSid == 0)
1102 return NULL;
1103
1104 // get the well known SID for BUILTIN\Administrators
1105 PSID administratorsSid = NULL;
1106 SID_IDENTIFIER_AUTHORITY SIDAuthAdministrators = SECURITY_NT_AUTHORITY;
1107
1108 if (!AllocateAndInitializeSid( &SIDAuthAdministrators, 2,
1109 SECURITY_BUILTIN_DOMAIN_RID,
1110 DOMAIN_ALIAS_RID_ADMINS,
1111 0, 0, 0, 0, 0, 0, &administratorsSid)) {
1112
1113 if (PrintMiscellaneous && Verbose) {
1114 warning("AllocateAndInitializeSid failure: "
1115 "lasterror = %d \n", GetLastError());
1116 }
1117 return NULL;
1118 }
1119
1120 // initialize the ace data for administrator group
1121 aces[1].pSid = administratorsSid;
1122 aces[1].mask = amask;
1123
1124 // get the well known SID for the universal Everybody
1125 PSID everybodySid = NULL;
1126 SID_IDENTIFIER_AUTHORITY SIDAuthEverybody = SECURITY_WORLD_SID_AUTHORITY;
1127
1128 if (!AllocateAndInitializeSid( &SIDAuthEverybody, 1, SECURITY_WORLD_RID,
1129 0, 0, 0, 0, 0, 0, 0, &everybodySid)) {
1130
1131 if (PrintMiscellaneous && Verbose) {
1132 warning("AllocateAndInitializeSid failure: "
1133 "lasterror = %d \n", GetLastError());
1134 }
1135 return NULL;
1136 }
1137
1138 // initialize the ace data for everybody else.
1139 aces[2].pSid = everybodySid;
1140 aces[2].mask = emask;
1141
1142 // create a security attributes structure with access control
1143 // entries as initialized above.
1144 LPSECURITY_ATTRIBUTES lpSA = make_security_attr(aces, 3);
1145 FREE_C_HEAP_ARRAY(char, aces[0].pSid, mtInternal);
1146 FreeSid(everybodySid);
1147 FreeSid(administratorsSid);
1148 return(lpSA);
1149 }
1150
1151
1152 // method to create the security attributes structure for restricting
1153 // access to the user temporary directory.
1154 //
1155 // the caller must free the resources associated with the security
1156 // attributes structure created by this method by calling the
1157 // free_security_attr() method.
1158 //
1159 static LPSECURITY_ATTRIBUTES make_tmpdir_security_attr() {
1160
1161 // create full access rights for the user/owner of the directory
1162 // and read-only access rights for everybody else. This is
1163 // effectively equivalent to UNIX 755 permissions on a directory.
1164 //
1165 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_ALL_ACCESS;
1166 DWORD emask = GENERIC_READ | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1167 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1168
1169 return make_user_everybody_admin_security_attr(umask, emask, amask);
1170 }
1171
1172 // method to create the security attributes structure for restricting
1173 // access to the shared memory backing store file.
1174 //
1175 // the caller must free the resources associated with the security
1176 // attributes structure created by this method by calling the
1177 // free_security_attr() method.
1178 //
1179 static LPSECURITY_ATTRIBUTES make_file_security_attr() {
1180
1181 // create extensive access rights for the user/owner of the file
1182 // and attribute read-only access rights for everybody else. This
1183 // is effectively equivalent to UNIX 600 permissions on a file.
1184 //
1185 DWORD umask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1186 DWORD emask = STANDARD_RIGHTS_READ | FILE_READ_ATTRIBUTES |
1187 FILE_READ_EA | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1188 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1189
1190 return make_user_everybody_admin_security_attr(umask, emask, amask);
1191 }
1192
1193 // method to create the security attributes structure for restricting
1194 // access to the name shared memory file mapping object.
1195 //
1196 // the caller must free the resources associated with the security
1197 // attributes structure created by this method by calling the
1198 // free_security_attr() method.
1199 //
1200 static LPSECURITY_ATTRIBUTES make_smo_security_attr() {
1201
1202 // create extensive access rights for the user/owner of the shared
1203 // memory object and attribute read-only access rights for everybody
1204 // else. This is effectively equivalent to UNIX 600 permissions on
1205 // on the shared memory object.
1206 //
1207 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_MAP_ALL_ACCESS;
1208 DWORD emask = STANDARD_RIGHTS_READ; // attributes only
1209 DWORD amask = STANDARD_RIGHTS_ALL | FILE_MAP_ALL_ACCESS;
1210
1211 return make_user_everybody_admin_security_attr(umask, emask, amask);
1212 }
1213
1214 // make the user specific temporary directory
1215 //
1216 static bool make_user_tmp_dir(const char* dirname) {
1217
1218
1219 LPSECURITY_ATTRIBUTES pDirSA = make_tmpdir_security_attr();
1220 if (pDirSA == NULL) {
1221 return false;
1222 }
1223
1224
1225 // create the directory with the given security attributes
1226 if (!CreateDirectory(dirname, pDirSA)) {
1227 DWORD lasterror = GetLastError();
1228 if (lasterror == ERROR_ALREADY_EXISTS) {
1229 // The directory already exists and was probably created by another
1230 // JVM instance. However, this could also be the result of a
1231 // deliberate symlink. Verify that the existing directory is safe.
1232 //
1233 if (!is_directory_secure(dirname)) {
1234 // directory is not secure
1235 if (PrintMiscellaneous && Verbose) {
1236 warning("%s directory is insecure\n", dirname);
1237 }
1238 return false;
1239 }
1240 // The administrator should be able to delete this directory.
1241 // But the directory created by previous version of JVM may not
1242 // have permission for administrators to delete this directory.
1243 // So add full permission to the administrator. Also setting new
1244 // DACLs might fix the corrupted the DACLs.
1245 SECURITY_INFORMATION secInfo = DACL_SECURITY_INFORMATION;
1246 if (!SetFileSecurity(dirname, secInfo, pDirSA->lpSecurityDescriptor)) {
1247 if (PrintMiscellaneous && Verbose) {
1248 lasterror = GetLastError();
1249 warning("SetFileSecurity failed for %s directory. lasterror %d \n",
1250 dirname, lasterror);
1251 }
1252 }
1253 }
1254 else {
1255 if (PrintMiscellaneous && Verbose) {
1256 warning("CreateDirectory failed: %d\n", GetLastError());
1257 }
1258 return false;
1259 }
1260 }
1261
1262 // free the security attributes structure
1263 free_security_attr(pDirSA);
1264
1265 return true;
1266 }
1267
1268 // create the shared memory resources
1269 //
1270 // This function creates the shared memory resources. This includes
1271 // the backing store file and the file mapping shared memory object.
1272 //
1273 static HANDLE create_sharedmem_resources(const char* dirname, const char* filename, const char* objectname, size_t size) {
1274
1275 HANDLE fh = INVALID_HANDLE_VALUE;
1276 HANDLE fmh = NULL;
1277
1278
1279 // create the security attributes for the backing store file
1280 LPSECURITY_ATTRIBUTES lpFileSA = make_file_security_attr();
1281 if (lpFileSA == NULL) {
1282 return NULL;
1283 }
1284
1285 // create the security attributes for the shared memory object
1286 LPSECURITY_ATTRIBUTES lpSmoSA = make_smo_security_attr();
1287 if (lpSmoSA == NULL) {
1288 free_security_attr(lpFileSA);
1289 return NULL;
1290 }
1291
1292 // create the user temporary directory
1293 if (!make_user_tmp_dir(dirname)) {
1294 // could not make/find the directory or the found directory
1295 // was not secure
1296 return NULL;
1297 }
1298
1299 // Create the file - the FILE_FLAG_DELETE_ON_CLOSE flag allows the
1300 // file to be deleted by the last process that closes its handle to
1301 // the file. This is important as the apis do not allow a terminating
1302 // JVM being monitored by another process to remove the file name.
1303 //
1304 // the FILE_SHARE_DELETE share mode is valid only in winnt
1305 //
1306 fh = CreateFile(
1307 filename, /* LPCTSTR file name */
1308
1309 GENERIC_READ|GENERIC_WRITE, /* DWORD desired access */
1310
1311 (os::win32::is_nt() ? FILE_SHARE_DELETE : 0)|
1312 FILE_SHARE_READ, /* DWORD share mode, future READONLY
1313 * open operations allowed
1314 */
1315 lpFileSA, /* LPSECURITY security attributes */
1316 CREATE_ALWAYS, /* DWORD creation disposition
1317 * create file, if it already
1318 * exists, overwrite it.
1319 */
1320 FILE_FLAG_DELETE_ON_CLOSE, /* DWORD flags and attributes */
1321
1322 NULL); /* HANDLE template file access */
1323
1324 free_security_attr(lpFileSA);
1325
1326 if (fh == INVALID_HANDLE_VALUE) {
1327 DWORD lasterror = GetLastError();
1328 if (PrintMiscellaneous && Verbose) {
1329 warning("could not create file %s: %d\n", filename, lasterror);
1330 }
1331 return NULL;
1332 }
1333
1334 // try to create the file mapping
1335 fmh = create_file_mapping(objectname, fh, lpSmoSA, size);
1336
1337 free_security_attr(lpSmoSA);
1338
1339 if (fmh == NULL) {
1340 // closing the file handle here will decrement the reference count
1341 // on the file. When all processes accessing the file close their
1342 // handle to it, the reference count will decrement to 0 and the
1343 // OS will delete the file. These semantics are requested by the
1344 // FILE_FLAG_DELETE_ON_CLOSE flag in CreateFile call above.
1345 CloseHandle(fh);
1346 fh = NULL;
1347 return NULL;
1348 } else {
1349 // We created the file mapping, but rarely the size of the
1350 // backing store file is reported as zero (0) which can cause
1351 // failures when trying to use the hsperfdata file.
1352 struct stat statbuf;
1353 int ret_code = ::stat(filename, &statbuf);
1354 if (ret_code == OS_ERR) {
1355 if (PrintMiscellaneous && Verbose) {
1356 warning("Could not get status information from file %s: %s\n",
1357 filename, strerror(errno));
1358 }
1359 CloseHandle(fmh);
1360 CloseHandle(fh);
1361 fh = NULL;
1362 fmh = NULL;
1363 return NULL;
1364 }
1365
1366 // We could always call FlushFileBuffers() but the Microsoft
1367 // docs indicate that it is considered expensive so we only
1368 // call it when we observe the size as zero (0).
1369 if (statbuf.st_size == 0 && FlushFileBuffers(fh) != TRUE) {
1370 DWORD lasterror = GetLastError();
1371 if (PrintMiscellaneous && Verbose) {
1372 warning("could not flush file %s: %d\n", filename, lasterror);
1373 }
1374 CloseHandle(fmh);
1375 CloseHandle(fh);
1376 fh = NULL;
1377 fmh = NULL;
1378 return NULL;
1379 }
1380 }
1381
1382 // the file has been successfully created and the file mapping
1383 // object has been created.
1384 sharedmem_fileHandle = fh;
1385 sharedmem_fileName = strdup(filename);
1386
1387 return fmh;
1388 }
1389
1390 // open the shared memory object for the given vmid.
1391 //
1392 static HANDLE open_sharedmem_object(const char* objectname, DWORD ofm_access, TRAPS) {
1393
1394 HANDLE fmh;
1395
1396 // open the file mapping with the requested mode
1397 fmh = OpenFileMapping(
1398 ofm_access, /* DWORD access mode */
1399 FALSE, /* BOOL inherit flag - Do not allow inherit */
1400 objectname); /* name for object */
1401
1402 if (fmh == NULL) {
1403 if (PrintMiscellaneous && Verbose) {
1404 warning("OpenFileMapping failed for shared memory object %s:"
1405 " lasterror = %d\n", objectname, GetLastError());
1406 }
1407 THROW_MSG_(vmSymbols::java_lang_Exception(),
1408 "Could not open PerfMemory", INVALID_HANDLE_VALUE);
1409 }
1410
1411 return fmh;;
1412 }
1413
1414 // create a named shared memory region
1415 //
1416 // On Win32, a named shared memory object has a name space that
1417 // is independent of the file system name space. Shared memory object,
1418 // or more precisely, file mapping objects, provide no mechanism to
1419 // inquire the size of the memory region. There is also no api to
1420 // enumerate the memory regions for various processes.
1421 //
1422 // This implementation utilizes the shared memory name space in parallel
1423 // with the file system name space. This allows us to determine the
1424 // size of the shared memory region from the size of the file and it
1425 // allows us to provide a common, file system based name space for
1426 // shared memory across platforms.
1427 //
1428 static char* mapping_create_shared(size_t size) {
1429
1430 void *mapAddress;
1431 int vmid = os::current_process_id();
1432
1433 // get the name of the user associated with this process
1434 char* user = get_user_name();
1435
1436 if (user == NULL) {
1437 return NULL;
1438 }
1439
1440 // construct the name of the user specific temporary directory
1441 char* dirname = get_user_tmp_dir(user);
1442
1443 // check that the file system is secure - i.e. it supports ACLs.
1444 if (!is_filesystem_secure(dirname)) {
1445 return NULL;
1446 }
1447
1448 // create the names of the backing store files and for the
1449 // share memory object.
1450 //
1451 char* filename = get_sharedmem_filename(dirname, vmid);
1452 char* objectname = get_sharedmem_objectname(user, vmid);
1453
1454 // cleanup any stale shared memory resources
1455 cleanup_sharedmem_resources(dirname);
1456
1457 assert(((size != 0) && (size % os::vm_page_size() == 0)),
1458 "unexpected PerfMemry region size");
1459
1460 FREE_C_HEAP_ARRAY(char, user, mtInternal);
1461
1462 // create the shared memory resources
1463 sharedmem_fileMapHandle =
1464 create_sharedmem_resources(dirname, filename, objectname, size);
1465
1466 FREE_C_HEAP_ARRAY(char, filename, mtInternal);
1467 FREE_C_HEAP_ARRAY(char, objectname, mtInternal);
1468 FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
1469
1470 if (sharedmem_fileMapHandle == NULL) {
1471 return NULL;
1472 }
1473
1474 // map the file into the address space
1475 mapAddress = MapViewOfFile(
1476 sharedmem_fileMapHandle, /* HANDLE = file mapping object */
1477 FILE_MAP_ALL_ACCESS, /* DWORD access flags */
1478 0, /* DWORD High word of offset */
1479 0, /* DWORD Low word of offset */
1480 (DWORD)size); /* DWORD Number of bytes to map */
1481
1482 if (mapAddress == NULL) {
1483 if (PrintMiscellaneous && Verbose) {
1484 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1485 }
1486 CloseHandle(sharedmem_fileMapHandle);
1487 sharedmem_fileMapHandle = NULL;
1488 return NULL;
1489 }
1490
1491 // clear the shared memory region
1492 (void)memset(mapAddress, '\0', size);
1493
1494 // it does not go through os api, the operation has to record from here
1495 MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress,
1496 size, CURRENT_PC, mtInternal);
1497
1498 return (char*) mapAddress;
1499 }
1500
1501 // this method deletes the file mapping object.
1502 //
1503 static void delete_file_mapping(char* addr, size_t size) {
1504
1505 // cleanup the persistent shared memory resources. since DestroyJavaVM does
1506 // not support unloading of the JVM, unmapping of the memory resource is not
1507 // performed. The memory will be reclaimed by the OS upon termination of all
1508 // processes mapping the resource. The file mapping handle and the file
1509 // handle are closed here to expedite the remove of the file by the OS. The
1510 // file is not removed directly because it was created with
1511 // FILE_FLAG_DELETE_ON_CLOSE semantics and any attempt to remove it would
1512 // be unsuccessful.
1513
1514 // close the fileMapHandle. the file mapping will still be retained
1515 // by the OS as long as any other JVM processes has an open file mapping
1516 // handle or a mapped view of the file.
1517 //
1518 if (sharedmem_fileMapHandle != NULL) {
1519 CloseHandle(sharedmem_fileMapHandle);
1520 sharedmem_fileMapHandle = NULL;
1521 }
1522
1523 // close the file handle. This will decrement the reference count on the
1524 // backing store file. When the reference count decrements to 0, the OS
1525 // will delete the file. These semantics apply because the file was
1526 // created with the FILE_FLAG_DELETE_ON_CLOSE flag.
1527 //
1528 if (sharedmem_fileHandle != INVALID_HANDLE_VALUE) {
1529 CloseHandle(sharedmem_fileHandle);
1530 sharedmem_fileHandle = INVALID_HANDLE_VALUE;
1531 }
1532 }
1533
1534 // this method determines the size of the shared memory file
1535 //
1536 static size_t sharedmem_filesize(const char* filename, TRAPS) {
1537
1538 struct stat statbuf;
1539
1540 // get the file size
1541 //
1542 // on win95/98/me, _stat returns a file size of 0 bytes, but on
1543 // winnt/2k the appropriate file size is returned. support for
1544 // the sharable aspects of performance counters was abandonded
1545 // on the non-nt win32 platforms due to this and other api
1546 // inconsistencies
1547 //
1548 if (::stat(filename, &statbuf) == OS_ERR) {
1549 if (PrintMiscellaneous && Verbose) {
1550 warning("stat %s failed: %s\n", filename, strerror(errno));
1551 }
1552 THROW_MSG_0(vmSymbols::java_io_IOException(),
1553 "Could not determine PerfMemory size");
1554 }
1555
1556 if ((statbuf.st_size == 0) || (statbuf.st_size % os::vm_page_size() != 0)) {
1557 if (PrintMiscellaneous && Verbose) {
1558 warning("unexpected file size: size = " SIZE_FORMAT "\n",
1559 statbuf.st_size);
1560 }
1561 THROW_MSG_0(vmSymbols::java_lang_Exception(),
1562 "Invalid PerfMemory size");
1563 }
1564
1565 return statbuf.st_size;
1566 }
1567
1568 // this method opens a file mapping object and maps the object
1569 // into the address space of the process
1570 //
1571 static void open_file_mapping(const char* user, int vmid,
1572 PerfMemory::PerfMemoryMode mode,
1573 char** addrp, size_t* sizep, TRAPS) {
1574
1575 ResourceMark rm;
1576
1577 void *mapAddress = 0;
1578 size_t size = 0;
1579 HANDLE fmh;
1580 DWORD ofm_access;
1581 DWORD mv_access;
1582 const char* luser = NULL;
1583
1584 if (mode == PerfMemory::PERF_MODE_RO) {
1585 ofm_access = FILE_MAP_READ;
1586 mv_access = FILE_MAP_READ;
1587 }
1588 else if (mode == PerfMemory::PERF_MODE_RW) {
1589 #ifdef LATER
1590 ofm_access = FILE_MAP_READ | FILE_MAP_WRITE;
1591 mv_access = FILE_MAP_READ | FILE_MAP_WRITE;
1592 #else
1593 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1594 "Unsupported access mode");
1595 #endif
1596 }
1597 else {
1598 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1599 "Illegal access mode");
1600 }
1601
1602 // if a user name wasn't specified, then find the user name for
1603 // the owner of the target vm.
1604 if (user == NULL || strlen(user) == 0) {
1605 luser = get_user_name(vmid);
1606 }
1607 else {
1608 luser = user;
1609 }
1610
1611 if (luser == NULL) {
1612 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1613 "Could not map vmid to user name");
1614 }
1615
1616 // get the names for the resources for the target vm
1617 char* dirname = get_user_tmp_dir(luser);
1618
1619 // since we don't follow symbolic links when creating the backing
1620 // store file, we also don't following them when attaching
1621 //
1622 if (!is_directory_secure(dirname)) {
1623 FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
1624 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1625 "Process not found");
1626 }
1627
1628 char* filename = get_sharedmem_filename(dirname, vmid);
1629 char* objectname = get_sharedmem_objectname(luser, vmid);
1630
1631 // copy heap memory to resource memory. the objectname and
1632 // filename are passed to methods that may throw exceptions.
1633 // using resource arrays for these names prevents the leaks
1634 // that would otherwise occur.
1635 //
1636 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
1637 char* robjectname = NEW_RESOURCE_ARRAY(char, strlen(objectname) + 1);
1638 strcpy(rfilename, filename);
1639 strcpy(robjectname, objectname);
1640
1641 // free the c heap resources that are no longer needed
1642 if (luser != user) FREE_C_HEAP_ARRAY(char, luser, mtInternal);
1643 FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
1644 FREE_C_HEAP_ARRAY(char, filename, mtInternal);
1645 FREE_C_HEAP_ARRAY(char, objectname, mtInternal);
1646
1647 if (*sizep == 0) {
1648 size = sharedmem_filesize(rfilename, CHECK);
1649 } else {
1650 size = *sizep;
1651 }
1652
1653 assert(size > 0, "unexpected size <= 0");
1654
1655 // Open the file mapping object with the given name
1656 fmh = open_sharedmem_object(robjectname, ofm_access, CHECK);
1657
1658 assert(fmh != INVALID_HANDLE_VALUE, "unexpected handle value");
1659
1660 // map the entire file into the address space
1661 mapAddress = MapViewOfFile(
1662 fmh, /* HANDLE Handle of file mapping object */
1663 mv_access, /* DWORD access flags */
1664 0, /* DWORD High word of offset */
1665 0, /* DWORD Low word of offset */
1666 size); /* DWORD Number of bytes to map */
1667
1668 if (mapAddress == NULL) {
1669 if (PrintMiscellaneous && Verbose) {
1670 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1671 }
1672 CloseHandle(fmh);
1673 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
1674 "Could not map PerfMemory");
1675 }
1676
1677 // it does not go through os api, the operation has to record from here
1678 MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress, size,
1679 CURRENT_PC, mtInternal);
1680
1681
1682 *addrp = (char*)mapAddress;
1683 *sizep = size;
1684
1685 // File mapping object can be closed at this time without
1686 // invalidating the mapped view of the file
1687 CloseHandle(fmh);
1688
1689 if (PerfTraceMemOps) {
1690 tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
1691 INTPTR_FORMAT "\n", size, vmid, mapAddress);
1692 }
1693 }
1694
1695 // this method unmaps the the mapped view of the the
1696 // file mapping object.
1697 //
1698 static void remove_file_mapping(char* addr) {
1699
1700 // the file mapping object was closed in open_file_mapping()
1701 // after the file map view was created. We only need to
1702 // unmap the file view here.
1703 UnmapViewOfFile(addr);
1704 }
1705
1706 // create the PerfData memory region in shared memory.
1707 static char* create_shared_memory(size_t size) {
1708
1709 return mapping_create_shared(size);
1710 }
1711
1712 // release a named, shared memory region
1713 //
1714 void delete_shared_memory(char* addr, size_t size) {
1715
1716 delete_file_mapping(addr, size);
1717 }
1718
1719
1720
1721
1722 // create the PerfData memory region
1723 //
1724 // This method creates the memory region used to store performance
1725 // data for the JVM. The memory may be created in standard or
1726 // shared memory.
1727 //
1728 void PerfMemory::create_memory_region(size_t size) {
1729
1730 if (PerfDisableSharedMem || !os::win32::is_nt()) {
1731 // do not share the memory for the performance data.
1732 PerfDisableSharedMem = true;
1733 _start = create_standard_memory(size);
1734 }
1735 else {
1736 _start = create_shared_memory(size);
1737 if (_start == NULL) {
1738
1739 // creation of the shared memory region failed, attempt
1740 // to create a contiguous, non-shared memory region instead.
1741 //
1742 if (PrintMiscellaneous && Verbose) {
1743 warning("Reverting to non-shared PerfMemory region.\n");
1744 }
1745 PerfDisableSharedMem = true;
1746 _start = create_standard_memory(size);
1747 }
1748 }
1749
1750 if (_start != NULL) _capacity = size;
1751
1752 }
1753
1754 // delete the PerfData memory region
1755 //
1756 // This method deletes the memory region used to store performance
1757 // data for the JVM. The memory region indicated by the <address, size>
1758 // tuple will be inaccessible after a call to this method.
1759 //
1760 void PerfMemory::delete_memory_region() {
1761
1762 assert((start() != NULL && capacity() > 0), "verify proper state");
1763
1764 // If user specifies PerfDataSaveFile, it will save the performance data
1765 // to the specified file name no matter whether PerfDataSaveToFile is specified
1766 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
1767 // -XX:+PerfDataSaveToFile.
1768 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
1769 save_memory_to_file(start(), capacity());
1770 }
1771
1772 if (PerfDisableSharedMem) {
1773 delete_standard_memory(start(), capacity());
1774 }
1775 else {
1776 delete_shared_memory(start(), capacity());
1777 }
1778 }
1779
1780 // attach to the PerfData memory region for another JVM
1781 //
1782 // This method returns an <address, size> tuple that points to
1783 // a memory buffer that is kept reasonably synchronized with
1784 // the PerfData memory region for the indicated JVM. This
1785 // buffer may be kept in synchronization via shared memory
1786 // or some other mechanism that keeps the buffer updated.
1787 //
1788 // If the JVM chooses not to support the attachability feature,
1789 // this method should throw an UnsupportedOperation exception.
1790 //
1791 // This implementation utilizes named shared memory to map
1792 // the indicated process's PerfData memory region into this JVMs
1793 // address space.
1794 //
1795 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode,
1796 char** addrp, size_t* sizep, TRAPS) {
1797
1798 if (vmid == 0 || vmid == os::current_process_id()) {
1799 *addrp = start();
1800 *sizep = capacity();
1801 return;
1802 }
1803
1804 open_file_mapping(user, vmid, mode, addrp, sizep, CHECK);
1805 }
1806
1807 // detach from the PerfData memory region of another JVM
1808 //
1809 // This method detaches the PerfData memory region of another
1810 // JVM, specified as an <address, size> tuple of a buffer
1811 // in this process's address space. This method may perform
1812 // arbitrary actions to accomplish the detachment. The memory
1813 // region specified by <address, size> will be inaccessible after
1814 // a call to this method.
1815 //
1816 // If the JVM chooses not to support the attachability feature,
1817 // this method should throw an UnsupportedOperation exception.
1818 //
1819 // This implementation utilizes named shared memory to detach
1820 // the indicated process's PerfData memory region from this
1821 // process's address space.
1822 //
1823 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
1824
1825 assert(addr != 0, "address sanity check");
1826 assert(bytes > 0, "capacity sanity check");
1827
1828 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
1829 // prevent accidental detachment of this process's PerfMemory region
1830 return;
1831 }
1832
1833 if (MemTracker::tracking_level() > NMT_minimal) {
1834 // it does not go through os api, the operation has to record from here
1835 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1836 remove_file_mapping(addr);
1837 tkr.record((address)addr, bytes);
1838 } else {
1839 remove_file_mapping(addr);
1840 }
1841 }
1842
1843 char* PerfMemory::backing_store_filename() {
1844 return sharedmem_fileName;
1845 }