1 /*
2 * Copyright (c) 2001, 2007, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 # include "incls/_precompiled.incl"
26 # include "incls/_perfMemory_windows.cpp.incl"
27
28 #include <windows.h>
29 #include <sys/types.h>
30 #include <sys/stat.h>
31 #include <errno.h>
32 #include <lmcons.h>
33
34 typedef BOOL (WINAPI *SetSecurityDescriptorControlFnPtr)(
35 IN PSECURITY_DESCRIPTOR pSecurityDescriptor,
36 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsOfInterest,
37 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsToSet);
38
39 // Standard Memory Implementation Details
40
41 // create the PerfData memory region in standard memory.
42 //
43 static char* create_standard_memory(size_t size) {
44
45 // allocate an aligned chuck of memory
46 char* mapAddress = os::reserve_memory(size);
47
48 if (mapAddress == NULL) {
49 return NULL;
50 }
51
52 // commit memory
53 if (!os::commit_memory(mapAddress, size)) {
54 if (PrintMiscellaneous && Verbose) {
55 warning("Could not commit PerfData memory\n");
56 }
57 os::release_memory(mapAddress, size);
58 return NULL;
59 }
60
61 return mapAddress;
62 }
63
64 // delete the PerfData memory region
65 //
66 static void delete_standard_memory(char* addr, size_t size) {
67
68 // there are no persistent external resources to cleanup for standard
69 // memory. since DestroyJavaVM does not support unloading of the JVM,
70 // cleanup of the memory resource is not performed. The memory will be
71 // reclaimed by the OS upon termination of the process.
72 //
73 return;
74
75 }
76
77 // save the specified memory region to the given file
78 //
79 static void save_memory_to_file(char* addr, size_t size) {
80
81 const char* destfile = PerfMemory::get_perfdata_file_path();
82 assert(destfile[0] != '\0', "invalid Perfdata file path");
83
84 int fd = ::_open(destfile, _O_BINARY|_O_CREAT|_O_WRONLY|_O_TRUNC,
85 _S_IREAD|_S_IWRITE);
86
87 if (fd == OS_ERR) {
88 if (PrintMiscellaneous && Verbose) {
89 warning("Could not create Perfdata save file: %s: %s\n",
90 destfile, strerror(errno));
91 }
92 } else {
93 for (size_t remaining = size; remaining > 0;) {
94
95 int nbytes = ::_write(fd, addr, (unsigned int)remaining);
96 if (nbytes == OS_ERR) {
97 if (PrintMiscellaneous && Verbose) {
98 warning("Could not write Perfdata save file: %s: %s\n",
99 destfile, strerror(errno));
100 }
101 break;
102 }
103
104 remaining -= (size_t)nbytes;
105 addr += nbytes;
106 }
107
108 int result = ::_close(fd);
109 if (PrintMiscellaneous && Verbose) {
110 if (result == OS_ERR) {
111 warning("Could not close %s: %s\n", destfile, strerror(errno));
112 }
113 }
114 }
115
116 FREE_C_HEAP_ARRAY(char, destfile);
117 }
118
119 // Shared Memory Implementation Details
120
121 // Note: the win32 shared memory implementation uses two objects to represent
122 // the shared memory: a windows kernel based file mapping object and a backing
123 // store file. On windows, the name space for shared memory is a kernel
124 // based name space that is disjoint from other win32 name spaces. Since Java
125 // is unaware of this name space, a parallel file system based name space is
126 // maintained, which provides a common file system based shared memory name
127 // space across the supported platforms and one that Java apps can deal with
128 // through simple file apis.
129 //
130 // For performance and resource cleanup reasons, it is recommended that the
131 // user specific directory and the backing store file be stored in either a
132 // RAM based file system or a local disk based file system. Network based
133 // file systems are not recommended for performance reasons. In addition,
134 // use of SMB network based file systems may result in unsuccesful cleanup
135 // of the disk based resource on exit of the VM. The Windows TMP and TEMP
136 // environement variables, as used by the GetTempPath() Win32 API (see
137 // os::get_temp_directory() in os_win32.cpp), control the location of the
138 // user specific directory and the shared memory backing store file.
139
140 static HANDLE sharedmem_fileMapHandle = NULL;
141 static HANDLE sharedmem_fileHandle = INVALID_HANDLE_VALUE;
142 static char* sharedmem_fileName = NULL;
143
144 // return the user specific temporary directory name.
145 //
146 // the caller is expected to free the allocated memory.
147 //
148 static char* get_user_tmp_dir(const char* user) {
149
150 const char* tmpdir = os::get_temp_directory();
151 const char* perfdir = PERFDATA_NAME;
152 size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
153 char* dirname = NEW_C_HEAP_ARRAY(char, nbytes);
154
155 // construct the path name to user specific tmp directory
156 _snprintf(dirname, nbytes, "%s\\%s_%s", tmpdir, perfdir, user);
157
158 return dirname;
159 }
160
161 // convert the given file name into a process id. if the file
162 // does not meet the file naming constraints, return 0.
163 //
164 static int filename_to_pid(const char* filename) {
165
166 // a filename that doesn't begin with a digit is not a
167 // candidate for conversion.
168 //
169 if (!isdigit(*filename)) {
170 return 0;
171 }
172
173 // check if file name can be converted to an integer without
174 // any leftover characters.
175 //
176 char* remainder = NULL;
177 errno = 0;
178 int pid = (int)strtol(filename, &remainder, 10);
179
180 if (errno != 0) {
181 return 0;
182 }
183
184 // check for left over characters. If any, then the filename is
185 // not a candidate for conversion.
186 //
187 if (remainder != NULL && *remainder != '\0') {
188 return 0;
189 }
190
191 // successful conversion, return the pid
192 return pid;
193 }
194
195 // check if the given path is considered a secure directory for
196 // the backing store files. Returns true if the directory exists
197 // and is considered a secure location. Returns false if the path
198 // is a symbolic link or if an error occurred.
199 //
200 static bool is_directory_secure(const char* path) {
201
202 DWORD fa;
203
204 fa = GetFileAttributes(path);
205 if (fa == 0xFFFFFFFF) {
206 DWORD lasterror = GetLastError();
207 if (lasterror == ERROR_FILE_NOT_FOUND) {
208 return false;
209 }
210 else {
211 // unexpected error, declare the path insecure
212 if (PrintMiscellaneous && Verbose) {
213 warning("could not get attributes for file %s: ",
214 " lasterror = %d\n", path, lasterror);
215 }
216 return false;
217 }
218 }
219
220 if (fa & FILE_ATTRIBUTE_REPARSE_POINT) {
221 // we don't accept any redirection for the user specific directory
222 // so declare the path insecure. This may be too conservative,
223 // as some types of reparse points might be acceptable, but it
224 // is probably more secure to avoid these conditions.
225 //
226 if (PrintMiscellaneous && Verbose) {
227 warning("%s is a reparse point\n", path);
228 }
229 return false;
230 }
231
232 if (fa & FILE_ATTRIBUTE_DIRECTORY) {
233 // this is the expected case. Since windows supports symbolic
234 // links to directories only, not to files, there is no need
235 // to check for open write permissions on the directory. If the
236 // directory has open write permissions, any files deposited that
237 // are not expected will be removed by the cleanup code.
238 //
239 return true;
240 }
241 else {
242 // this is either a regular file or some other type of file,
243 // any of which are unexpected and therefore insecure.
244 //
245 if (PrintMiscellaneous && Verbose) {
246 warning("%s is not a directory, file attributes = "
247 INTPTR_FORMAT "\n", path, fa);
248 }
249 return false;
250 }
251 }
252
253 // return the user name for the owner of this process
254 //
255 // the caller is expected to free the allocated memory.
256 //
257 static char* get_user_name() {
258
259 /* get the user name. This code is adapted from code found in
260 * the jdk in src/windows/native/java/lang/java_props_md.c
261 * java_props_md.c 1.29 02/02/06. According to the original
262 * source, the call to GetUserName is avoided because of a resulting
263 * increase in footprint of 100K.
264 */
265 char* user = getenv("USERNAME");
266 char buf[UNLEN+1];
267 DWORD buflen = sizeof(buf);
268 if (user == NULL || strlen(user) == 0) {
269 if (GetUserName(buf, &buflen)) {
270 user = buf;
271 }
272 else {
273 return NULL;
274 }
275 }
276
277 char* user_name = NEW_C_HEAP_ARRAY(char, strlen(user)+1);
278 strcpy(user_name, user);
279
280 return user_name;
281 }
282
283 // return the name of the user that owns the process identified by vmid.
284 //
285 // This method uses a slow directory search algorithm to find the backing
286 // store file for the specified vmid and returns the user name, as determined
287 // by the user name suffix of the hsperfdata_<username> directory name.
288 //
289 // the caller is expected to free the allocated memory.
290 //
291 static char* get_user_name_slow(int vmid) {
292
293 // directory search
294 char* oldest_user = NULL;
295 time_t oldest_ctime = 0;
296
297 const char* tmpdirname = os::get_temp_directory();
298
299 DIR* tmpdirp = os::opendir(tmpdirname);
300
301 if (tmpdirp == NULL) {
302 return NULL;
303 }
304
305 // for each entry in the directory that matches the pattern hsperfdata_*,
306 // open the directory and check if the file for the given vmid exists.
307 // The file with the expected name and the latest creation date is used
308 // to determine the user name for the process id.
309 //
310 struct dirent* dentry;
311 char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname));
312 errno = 0;
313 while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
314
315 // check if the directory entry is a hsperfdata file
316 if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
317 continue;
318 }
319
320 char* usrdir_name = NEW_C_HEAP_ARRAY(char,
321 strlen(tmpdirname) + strlen(dentry->d_name) + 2);
322 strcpy(usrdir_name, tmpdirname);
323 strcat(usrdir_name, "\\");
324 strcat(usrdir_name, dentry->d_name);
325
326 DIR* subdirp = os::opendir(usrdir_name);
327
328 if (subdirp == NULL) {
329 FREE_C_HEAP_ARRAY(char, usrdir_name);
330 continue;
331 }
332
333 // Since we don't create the backing store files in directories
334 // pointed to by symbolic links, we also don't follow them when
335 // looking for the files. We check for a symbolic link after the
336 // call to opendir in order to eliminate a small window where the
337 // symlink can be exploited.
338 //
339 if (!is_directory_secure(usrdir_name)) {
340 FREE_C_HEAP_ARRAY(char, usrdir_name);
341 os::closedir(subdirp);
342 continue;
343 }
344
345 struct dirent* udentry;
346 char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name));
347 errno = 0;
348 while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
349
350 if (filename_to_pid(udentry->d_name) == vmid) {
351 struct stat statbuf;
352
353 char* filename = NEW_C_HEAP_ARRAY(char,
354 strlen(usrdir_name) + strlen(udentry->d_name) + 2);
355
356 strcpy(filename, usrdir_name);
357 strcat(filename, "\\");
358 strcat(filename, udentry->d_name);
359
360 if (::stat(filename, &statbuf) == OS_ERR) {
361 FREE_C_HEAP_ARRAY(char, filename);
362 continue;
363 }
364
365 // skip over files that are not regular files.
366 if ((statbuf.st_mode & S_IFMT) != S_IFREG) {
367 FREE_C_HEAP_ARRAY(char, filename);
368 continue;
369 }
370
371 // compare and save filename with latest creation time
372 if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
373
374 if (statbuf.st_ctime > oldest_ctime) {
375 char* user = strchr(dentry->d_name, '_') + 1;
376
377 if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user);
378 oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1);
379
380 strcpy(oldest_user, user);
381 oldest_ctime = statbuf.st_ctime;
382 }
383 }
384
385 FREE_C_HEAP_ARRAY(char, filename);
386 }
387 }
388 os::closedir(subdirp);
389 FREE_C_HEAP_ARRAY(char, udbuf);
390 FREE_C_HEAP_ARRAY(char, usrdir_name);
391 }
392 os::closedir(tmpdirp);
393 FREE_C_HEAP_ARRAY(char, tdbuf);
394
395 return(oldest_user);
396 }
397
398 // return the name of the user that owns the process identified by vmid.
399 //
400 // note: this method should only be used via the Perf native methods.
401 // There are various costs to this method and limiting its use to the
402 // Perf native methods limits the impact to monitoring applications only.
403 //
404 static char* get_user_name(int vmid) {
405
406 // A fast implementation is not provided at this time. It's possible
407 // to provide a fast process id to user name mapping function using
408 // the win32 apis, but the default ACL for the process object only
409 // allows processes with the same owner SID to acquire the process
410 // handle (via OpenProcess(PROCESS_QUERY_INFORMATION)). It's possible
411 // to have the JVM change the ACL for the process object to allow arbitrary
412 // users to access the process handle and the process security token.
413 // The security ramifications need to be studied before providing this
414 // mechanism.
415 //
416 return get_user_name_slow(vmid);
417 }
418
419 // return the name of the shared memory file mapping object for the
420 // named shared memory region for the given user name and vmid.
421 //
422 // The file mapping object's name is not the file name. It is a name
423 // in a separate name space.
424 //
425 // the caller is expected to free the allocated memory.
426 //
427 static char *get_sharedmem_objectname(const char* user, int vmid) {
428
429 // construct file mapping object's name, add 3 for two '_' and a
430 // null terminator.
431 int nbytes = (int)strlen(PERFDATA_NAME) + (int)strlen(user) + 3;
432
433 // the id is converted to an unsigned value here because win32 allows
434 // negative process ids. However, OpenFileMapping API complains
435 // about a name containing a '-' characters.
436 //
437 nbytes += UINT_CHARS;
438 char* name = NEW_C_HEAP_ARRAY(char, nbytes);
439 _snprintf(name, nbytes, "%s_%s_%u", PERFDATA_NAME, user, vmid);
440
441 return name;
442 }
443
444 // return the file name of the backing store file for the named
445 // shared memory region for the given user name and vmid.
446 //
447 // the caller is expected to free the allocated memory.
448 //
449 static char* get_sharedmem_filename(const char* dirname, int vmid) {
450
451 // add 2 for the file separator and a null terminator.
452 size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
453
454 char* name = NEW_C_HEAP_ARRAY(char, nbytes);
455 _snprintf(name, nbytes, "%s\\%d", dirname, vmid);
456
457 return name;
458 }
459
460 // remove file
461 //
462 // this method removes the file with the given file name.
463 //
464 // Note: if the indicated file is on an SMB network file system, this
465 // method may be unsuccessful in removing the file.
466 //
467 static void remove_file(const char* dirname, const char* filename) {
468
469 size_t nbytes = strlen(dirname) + strlen(filename) + 2;
470 char* path = NEW_C_HEAP_ARRAY(char, nbytes);
471
472 strcpy(path, dirname);
473 strcat(path, "\\");
474 strcat(path, filename);
475
476 if (::unlink(path) == OS_ERR) {
477 if (PrintMiscellaneous && Verbose) {
478 if (errno != ENOENT) {
479 warning("Could not unlink shared memory backing"
480 " store file %s : %s\n", path, strerror(errno));
481 }
482 }
483 }
484
485 FREE_C_HEAP_ARRAY(char, path);
486 }
487
488 // returns true if the process represented by pid is alive, otherwise
489 // returns false. the validity of the result is only accurate if the
490 // target process is owned by the same principal that owns this process.
491 // this method should not be used if to test the status of an otherwise
492 // arbitrary process unless it is know that this process has the appropriate
493 // privileges to guarantee a result valid.
494 //
495 static bool is_alive(int pid) {
496
497 HANDLE ph = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);
498 if (ph == NULL) {
499 // the process does not exist.
500 if (PrintMiscellaneous && Verbose) {
501 DWORD lastError = GetLastError();
502 if (lastError != ERROR_INVALID_PARAMETER) {
503 warning("OpenProcess failed: %d\n", GetLastError());
504 }
505 }
506 return false;
507 }
508
509 DWORD exit_status;
510 if (!GetExitCodeProcess(ph, &exit_status)) {
511 if (PrintMiscellaneous && Verbose) {
512 warning("GetExitCodeProcess failed: %d\n", GetLastError());
513 }
514 CloseHandle(ph);
515 return false;
516 }
517
518 CloseHandle(ph);
519 return (exit_status == STILL_ACTIVE) ? true : false;
520 }
521
522 // check if the file system is considered secure for the backing store files
523 //
524 static bool is_filesystem_secure(const char* path) {
525
526 char root_path[MAX_PATH];
527 char fs_type[MAX_PATH];
528
529 if (PerfBypassFileSystemCheck) {
530 if (PrintMiscellaneous && Verbose) {
531 warning("bypassing file system criteria checks for %s\n", path);
532 }
533 return true;
534 }
535
536 char* first_colon = strchr((char *)path, ':');
537 if (first_colon == NULL) {
538 if (PrintMiscellaneous && Verbose) {
539 warning("expected device specifier in path: %s\n", path);
540 }
541 return false;
542 }
543
544 size_t len = (size_t)(first_colon - path);
545 assert(len + 2 <= MAX_PATH, "unexpected device specifier length");
546 strncpy(root_path, path, len + 1);
547 root_path[len + 1] = '\\';
548 root_path[len + 2] = '\0';
549
550 // check that we have something like "C:\" or "AA:\"
551 assert(strlen(root_path) >= 3, "device specifier too short");
552 assert(strchr(root_path, ':') != NULL, "bad device specifier format");
553 assert(strchr(root_path, '\\') != NULL, "bad device specifier format");
554
555 DWORD maxpath;
556 DWORD flags;
557
558 if (!GetVolumeInformation(root_path, NULL, 0, NULL, &maxpath,
559 &flags, fs_type, MAX_PATH)) {
560 // we can't get information about the volume, so assume unsafe.
561 if (PrintMiscellaneous && Verbose) {
562 warning("could not get device information for %s: "
563 " path = %s: lasterror = %d\n",
564 root_path, path, GetLastError());
565 }
566 return false;
567 }
568
569 if ((flags & FS_PERSISTENT_ACLS) == 0) {
570 // file system doesn't support ACLs, declare file system unsafe
571 if (PrintMiscellaneous && Verbose) {
572 warning("file system type %s on device %s does not support"
573 " ACLs\n", fs_type, root_path);
574 }
575 return false;
576 }
577
578 if ((flags & FS_VOL_IS_COMPRESSED) != 0) {
579 // file system is compressed, declare file system unsafe
580 if (PrintMiscellaneous && Verbose) {
581 warning("file system type %s on device %s is compressed\n",
582 fs_type, root_path);
583 }
584 return false;
585 }
586
587 return true;
588 }
589
590 // cleanup stale shared memory resources
591 //
592 // This method attempts to remove all stale shared memory files in
593 // the named user temporary directory. It scans the named directory
594 // for files matching the pattern ^$[0-9]*$. For each file found, the
595 // process id is extracted from the file name and a test is run to
596 // determine if the process is alive. If the process is not alive,
597 // any stale file resources are removed.
598 //
599 static void cleanup_sharedmem_resources(const char* dirname) {
600
601 // open the user temp directory
602 DIR* dirp = os::opendir(dirname);
603
604 if (dirp == NULL) {
605 // directory doesn't exist, so there is nothing to cleanup
606 return;
607 }
608
609 if (!is_directory_secure(dirname)) {
610 // the directory is not secure, don't attempt any cleanup
611 return;
612 }
613
614 // for each entry in the directory that matches the expected file
615 // name pattern, determine if the file resources are stale and if
616 // so, remove the file resources. Note, instrumented HotSpot processes
617 // for this user may start and/or terminate during this search and
618 // remove or create new files in this directory. The behavior of this
619 // loop under these conditions is dependent upon the implementation of
620 // opendir/readdir.
621 //
622 struct dirent* entry;
623 char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname));
624 errno = 0;
625 while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
626
627 int pid = filename_to_pid(entry->d_name);
628
629 if (pid == 0) {
630
631 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
632
633 // attempt to remove all unexpected files, except "." and ".."
634 remove_file(dirname, entry->d_name);
635 }
636
637 errno = 0;
638 continue;
639 }
640
641 // we now have a file name that converts to a valid integer
642 // that could represent a process id . if this process id
643 // matches the current process id or the process is not running,
644 // then remove the stale file resources.
645 //
646 // process liveness is detected by checking the exit status
647 // of the process. if the process id is valid and the exit status
648 // indicates that it is still running, the file file resources
649 // are not removed. If the process id is invalid, or if we don't
650 // have permissions to check the process status, or if the process
651 // id is valid and the process has terminated, the the file resources
652 // are assumed to be stale and are removed.
653 //
654 if (pid == os::current_process_id() || !is_alive(pid)) {
655
656 // we can only remove the file resources. Any mapped views
657 // of the file can only be unmapped by the processes that
658 // opened those views and the file mapping object will not
659 // get removed until all views are unmapped.
660 //
661 remove_file(dirname, entry->d_name);
662 }
663 errno = 0;
664 }
665 os::closedir(dirp);
666 FREE_C_HEAP_ARRAY(char, dbuf);
667 }
668
669 // create a file mapping object with the requested name, and size
670 // from the file represented by the given Handle object
671 //
672 static HANDLE create_file_mapping(const char* name, HANDLE fh, LPSECURITY_ATTRIBUTES fsa, size_t size) {
673
674 DWORD lowSize = (DWORD)size;
675 DWORD highSize = 0;
676 HANDLE fmh = NULL;
677
678 // Create a file mapping object with the given name. This function
679 // will grow the file to the specified size.
680 //
681 fmh = CreateFileMapping(
682 fh, /* HANDLE file handle for backing store */
683 fsa, /* LPSECURITY_ATTRIBUTES Not inheritable */
684 PAGE_READWRITE, /* DWORD protections */
685 highSize, /* DWORD High word of max size */
686 lowSize, /* DWORD Low word of max size */
687 name); /* LPCTSTR name for object */
688
689 if (fmh == NULL) {
690 if (PrintMiscellaneous && Verbose) {
691 warning("CreateFileMapping failed, lasterror = %d\n", GetLastError());
692 }
693 return NULL;
694 }
695
696 if (GetLastError() == ERROR_ALREADY_EXISTS) {
697
698 // a stale file mapping object was encountered. This object may be
699 // owned by this or some other user and cannot be removed until
700 // the other processes either exit or close their mapping objects
701 // and/or mapped views of this mapping object.
702 //
703 if (PrintMiscellaneous && Verbose) {
704 warning("file mapping already exists, lasterror = %d\n", GetLastError());
705 }
706
707 CloseHandle(fmh);
708 return NULL;
709 }
710
711 return fmh;
712 }
713
714
715 // method to free the given security descriptor and the contained
716 // access control list.
717 //
718 static void free_security_desc(PSECURITY_DESCRIPTOR pSD) {
719
720 BOOL success, exists, isdefault;
721 PACL pACL;
722
723 if (pSD != NULL) {
724
725 // get the access control list from the security descriptor
726 success = GetSecurityDescriptorDacl(pSD, &exists, &pACL, &isdefault);
727
728 // if an ACL existed and it was not a default acl, then it must
729 // be an ACL we enlisted. free the resources.
730 //
731 if (success && exists && pACL != NULL && !isdefault) {
732 FREE_C_HEAP_ARRAY(char, pACL);
733 }
734
735 // free the security descriptor
736 FREE_C_HEAP_ARRAY(char, pSD);
737 }
738 }
739
740 // method to free up a security attributes structure and any
741 // contained security descriptors and ACL
742 //
743 static void free_security_attr(LPSECURITY_ATTRIBUTES lpSA) {
744
745 if (lpSA != NULL) {
746 // free the contained security descriptor and the ACL
747 free_security_desc(lpSA->lpSecurityDescriptor);
748 lpSA->lpSecurityDescriptor = NULL;
749
750 // free the security attributes structure
751 FREE_C_HEAP_ARRAY(char, lpSA);
752 }
753 }
754
755 // get the user SID for the process indicated by the process handle
756 //
757 static PSID get_user_sid(HANDLE hProcess) {
758
759 HANDLE hAccessToken;
760 PTOKEN_USER token_buf = NULL;
761 DWORD rsize = 0;
762
763 if (hProcess == NULL) {
764 return NULL;
765 }
766
767 // get the process token
768 if (!OpenProcessToken(hProcess, TOKEN_READ, &hAccessToken)) {
769 if (PrintMiscellaneous && Verbose) {
770 warning("OpenProcessToken failure: lasterror = %d \n", GetLastError());
771 }
772 return NULL;
773 }
774
775 // determine the size of the token structured needed to retrieve
776 // the user token information from the access token.
777 //
778 if (!GetTokenInformation(hAccessToken, TokenUser, NULL, rsize, &rsize)) {
779 DWORD lasterror = GetLastError();
780 if (lasterror != ERROR_INSUFFICIENT_BUFFER) {
781 if (PrintMiscellaneous && Verbose) {
782 warning("GetTokenInformation failure: lasterror = %d,"
783 " rsize = %d\n", lasterror, rsize);
784 }
785 CloseHandle(hAccessToken);
786 return NULL;
787 }
788 }
789
790 token_buf = (PTOKEN_USER) NEW_C_HEAP_ARRAY(char, rsize);
791
792 // get the user token information
793 if (!GetTokenInformation(hAccessToken, TokenUser, token_buf, rsize, &rsize)) {
794 if (PrintMiscellaneous && Verbose) {
795 warning("GetTokenInformation failure: lasterror = %d,"
796 " rsize = %d\n", GetLastError(), rsize);
797 }
798 FREE_C_HEAP_ARRAY(char, token_buf);
799 CloseHandle(hAccessToken);
800 return NULL;
801 }
802
803 DWORD nbytes = GetLengthSid(token_buf->User.Sid);
804 PSID pSID = NEW_C_HEAP_ARRAY(char, nbytes);
805
806 if (!CopySid(nbytes, pSID, token_buf->User.Sid)) {
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);
812 FREE_C_HEAP_ARRAY(char, pSID);
813 CloseHandle(hAccessToken);
814 return NULL;
815 }
816
817 // close the access token.
818 CloseHandle(hAccessToken);
819 FREE_C_HEAP_ARRAY(char, token_buf);
820
821 return pSID;
822 }
823
824 // structure used to consolidate access control entry information
825 //
826 typedef struct ace_data {
827 PSID pSid; // SID of the ACE
828 DWORD mask; // mask for the ACE
829 } ace_data_t;
830
831
832 // method to add an allow access control entry with the access rights
833 // indicated in mask for the principal indicated in SID to the given
834 // security descriptor. Much of the DACL handling was adapted from
835 // the example provided here:
836 // http://support.microsoft.com/kb/102102/EN-US/
837 //
838
839 static bool add_allow_aces(PSECURITY_DESCRIPTOR pSD,
840 ace_data_t aces[], int ace_count) {
841 PACL newACL = NULL;
842 PACL oldACL = NULL;
843
844 if (pSD == NULL) {
845 return false;
846 }
847
848 BOOL exists, isdefault;
849
850 // retrieve any existing access control list.
851 if (!GetSecurityDescriptorDacl(pSD, &exists, &oldACL, &isdefault)) {
852 if (PrintMiscellaneous && Verbose) {
853 warning("GetSecurityDescriptor failure: lasterror = %d \n",
854 GetLastError());
855 }
856 return false;
857 }
858
859 // get the size of the DACL
860 ACL_SIZE_INFORMATION aclinfo;
861
862 // GetSecurityDescriptorDacl may return true value for exists (lpbDaclPresent)
863 // while oldACL is NULL for some case.
864 if (oldACL == NULL) {
865 exists = FALSE;
866 }
867
868 if (exists) {
869 if (!GetAclInformation(oldACL, &aclinfo,
870 sizeof(ACL_SIZE_INFORMATION),
871 AclSizeInformation)) {
872 if (PrintMiscellaneous && Verbose) {
873 warning("GetAclInformation failure: lasterror = %d \n", GetLastError());
874 return false;
875 }
876 }
877 } else {
878 aclinfo.AceCount = 0; // assume NULL DACL
879 aclinfo.AclBytesFree = 0;
880 aclinfo.AclBytesInUse = sizeof(ACL);
881 }
882
883 // compute the size needed for the new ACL
884 // initial size of ACL is sum of the following:
885 // * size of ACL structure.
886 // * size of each ACE structure that ACL is to contain minus the sid
887 // sidStart member (DWORD) of the ACE.
888 // * length of the SID that each ACE is to contain.
889 DWORD newACLsize = aclinfo.AclBytesInUse +
890 (sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD)) * ace_count;
891 for (int i = 0; i < ace_count; i++) {
892 newACLsize += GetLengthSid(aces[i].pSid);
893 }
894
895 // create the new ACL
896 newACL = (PACL) NEW_C_HEAP_ARRAY(char, newACLsize);
897
898 if (!InitializeAcl(newACL, newACLsize, ACL_REVISION)) {
899 if (PrintMiscellaneous && Verbose) {
900 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
901 }
902 FREE_C_HEAP_ARRAY(char, newACL);
903 return false;
904 }
905
906 unsigned int ace_index = 0;
907 // copy any existing ACEs from the old ACL (if any) to the new ACL.
908 if (aclinfo.AceCount != 0) {
909 while (ace_index < aclinfo.AceCount) {
910 LPVOID ace;
911 if (!GetAce(oldACL, ace_index, &ace)) {
912 if (PrintMiscellaneous && Verbose) {
913 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
914 }
915 FREE_C_HEAP_ARRAY(char, newACL);
916 return false;
917 }
918 if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceFlags && INHERITED_ACE) {
919 // this is an inherited, allowed ACE; break from loop so we can
920 // add the new access allowed, non-inherited ACE in the correct
921 // position, immediately following all non-inherited ACEs.
922 break;
923 }
924
925 // determine if the SID of this ACE matches any of the SIDs
926 // for which we plan to set ACEs.
927 int matches = 0;
928 for (int i = 0; i < ace_count; i++) {
929 if (EqualSid(aces[i].pSid, &(((ACCESS_ALLOWED_ACE *)ace)->SidStart))) {
930 matches++;
931 break;
932 }
933 }
934
935 // if there are no SID matches, then add this existing ACE to the new ACL
936 if (matches == 0) {
937 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
938 ((PACE_HEADER)ace)->AceSize)) {
939 if (PrintMiscellaneous && Verbose) {
940 warning("AddAce failure: lasterror = %d \n", GetLastError());
941 }
942 FREE_C_HEAP_ARRAY(char, newACL);
943 return false;
944 }
945 }
946 ace_index++;
947 }
948 }
949
950 // add the passed-in access control entries to the new ACL
951 for (int i = 0; i < ace_count; i++) {
952 if (!AddAccessAllowedAce(newACL, ACL_REVISION,
953 aces[i].mask, aces[i].pSid)) {
954 if (PrintMiscellaneous && Verbose) {
955 warning("AddAccessAllowedAce failure: lasterror = %d \n",
956 GetLastError());
957 }
958 FREE_C_HEAP_ARRAY(char, newACL);
959 return false;
960 }
961 }
962
963 // now copy the rest of the inherited ACEs from the old ACL
964 if (aclinfo.AceCount != 0) {
965 // picking up at ace_index, where we left off in the
966 // previous ace_index loop
967 while (ace_index < aclinfo.AceCount) {
968 LPVOID ace;
969 if (!GetAce(oldACL, ace_index, &ace)) {
970 if (PrintMiscellaneous && Verbose) {
971 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
972 }
973 FREE_C_HEAP_ARRAY(char, newACL);
974 return false;
975 }
976 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
977 ((PACE_HEADER)ace)->AceSize)) {
978 if (PrintMiscellaneous && Verbose) {
979 warning("AddAce failure: lasterror = %d \n", GetLastError());
980 }
981 FREE_C_HEAP_ARRAY(char, newACL);
982 return false;
983 }
984 ace_index++;
985 }
986 }
987
988 // add the new ACL to the security descriptor.
989 if (!SetSecurityDescriptorDacl(pSD, TRUE, newACL, FALSE)) {
990 if (PrintMiscellaneous && Verbose) {
991 warning("SetSecurityDescriptorDacl failure:"
992 " lasterror = %d \n", GetLastError());
993 }
994 FREE_C_HEAP_ARRAY(char, newACL);
995 return false;
996 }
997
998 // if running on windows 2000 or later, set the automatic inheritance
999 // control flags.
1000 SetSecurityDescriptorControlFnPtr _SetSecurityDescriptorControl;
1001 _SetSecurityDescriptorControl = (SetSecurityDescriptorControlFnPtr)
1002 GetProcAddress(GetModuleHandle(TEXT("advapi32.dll")),
1003 "SetSecurityDescriptorControl");
1004
1005 if (_SetSecurityDescriptorControl != NULL) {
1006 // We do not want to further propagate inherited DACLs, so making them
1007 // protected prevents that.
1008 if (!_SetSecurityDescriptorControl(pSD, SE_DACL_PROTECTED,
1009 SE_DACL_PROTECTED)) {
1010 if (PrintMiscellaneous && Verbose) {
1011 warning("SetSecurityDescriptorControl failure:"
1012 " lasterror = %d \n", GetLastError());
1013 }
1014 FREE_C_HEAP_ARRAY(char, newACL);
1015 return false;
1016 }
1017 }
1018 // Note, the security descriptor maintains a reference to the newACL, not
1019 // a copy of it. Therefore, the newACL is not freed here. It is freed when
1020 // the security descriptor containing its reference is freed.
1021 //
1022 return true;
1023 }
1024
1025 // method to create a security attributes structure, which contains a
1026 // security descriptor and an access control list comprised of 0 or more
1027 // access control entries. The method take an array of ace_data structures
1028 // that indicate the ACE to be added to the security descriptor.
1029 //
1030 // the caller must free the resources associated with the security
1031 // attributes structure created by this method by calling the
1032 // free_security_attr() method.
1033 //
1034 static LPSECURITY_ATTRIBUTES make_security_attr(ace_data_t aces[], int count) {
1035
1036 // allocate space for a security descriptor
1037 PSECURITY_DESCRIPTOR pSD = (PSECURITY_DESCRIPTOR)
1038 NEW_C_HEAP_ARRAY(char, SECURITY_DESCRIPTOR_MIN_LENGTH);
1039
1040 // initialize the security descriptor
1041 if (!InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION)) {
1042 if (PrintMiscellaneous && Verbose) {
1043 warning("InitializeSecurityDescriptor failure: "
1044 "lasterror = %d \n", GetLastError());
1045 }
1046 free_security_desc(pSD);
1047 return NULL;
1048 }
1049
1050 // add the access control entries
1051 if (!add_allow_aces(pSD, aces, count)) {
1052 free_security_desc(pSD);
1053 return NULL;
1054 }
1055
1056 // allocate and initialize the security attributes structure and
1057 // return it to the caller.
1058 //
1059 LPSECURITY_ATTRIBUTES lpSA = (LPSECURITY_ATTRIBUTES)
1060 NEW_C_HEAP_ARRAY(char, sizeof(SECURITY_ATTRIBUTES));
1061 lpSA->nLength = sizeof(SECURITY_ATTRIBUTES);
1062 lpSA->lpSecurityDescriptor = pSD;
1063 lpSA->bInheritHandle = FALSE;
1064
1065 return(lpSA);
1066 }
1067
1068 // method to create a security attributes structure with a restrictive
1069 // access control list that creates a set access rights for the user/owner
1070 // of the securable object and a separate set access rights for everyone else.
1071 // also provides for full access rights for the administrator group.
1072 //
1073 // the caller must free the resources associated with the security
1074 // attributes structure created by this method by calling the
1075 // free_security_attr() method.
1076 //
1077
1078 static LPSECURITY_ATTRIBUTES make_user_everybody_admin_security_attr(
1079 DWORD umask, DWORD emask, DWORD amask) {
1080
1081 ace_data_t aces[3];
1082
1083 // initialize the user ace data
1084 aces[0].pSid = get_user_sid(GetCurrentProcess());
1085 aces[0].mask = umask;
1086
1087 // get the well known SID for BUILTIN\Administrators
1088 PSID administratorsSid = NULL;
1089 SID_IDENTIFIER_AUTHORITY SIDAuthAdministrators = SECURITY_NT_AUTHORITY;
1090
1091 if (!AllocateAndInitializeSid( &SIDAuthAdministrators, 2,
1092 SECURITY_BUILTIN_DOMAIN_RID,
1093 DOMAIN_ALIAS_RID_ADMINS,
1094 0, 0, 0, 0, 0, 0, &administratorsSid)) {
1095
1096 if (PrintMiscellaneous && Verbose) {
1097 warning("AllocateAndInitializeSid failure: "
1098 "lasterror = %d \n", GetLastError());
1099 }
1100 return NULL;
1101 }
1102
1103 // initialize the ace data for administrator group
1104 aces[1].pSid = administratorsSid;
1105 aces[1].mask = amask;
1106
1107 // get the well known SID for the universal Everybody
1108 PSID everybodySid = NULL;
1109 SID_IDENTIFIER_AUTHORITY SIDAuthEverybody = SECURITY_WORLD_SID_AUTHORITY;
1110
1111 if (!AllocateAndInitializeSid( &SIDAuthEverybody, 1, SECURITY_WORLD_RID,
1112 0, 0, 0, 0, 0, 0, 0, &everybodySid)) {
1113
1114 if (PrintMiscellaneous && Verbose) {
1115 warning("AllocateAndInitializeSid failure: "
1116 "lasterror = %d \n", GetLastError());
1117 }
1118 return NULL;
1119 }
1120
1121 // initialize the ace data for everybody else.
1122 aces[2].pSid = everybodySid;
1123 aces[2].mask = emask;
1124
1125 // create a security attributes structure with access control
1126 // entries as initialized above.
1127 LPSECURITY_ATTRIBUTES lpSA = make_security_attr(aces, 3);
1128 FREE_C_HEAP_ARRAY(char, aces[0].pSid);
1129 FreeSid(everybodySid);
1130 FreeSid(administratorsSid);
1131 return(lpSA);
1132 }
1133
1134
1135 // method to create the security attributes structure for restricting
1136 // access to the user temporary directory.
1137 //
1138 // the caller must free the resources associated with the security
1139 // attributes structure created by this method by calling the
1140 // free_security_attr() method.
1141 //
1142 static LPSECURITY_ATTRIBUTES make_tmpdir_security_attr() {
1143
1144 // create full access rights for the user/owner of the directory
1145 // and read-only access rights for everybody else. This is
1146 // effectively equivalent to UNIX 755 permissions on a directory.
1147 //
1148 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_ALL_ACCESS;
1149 DWORD emask = GENERIC_READ | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1150 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1151
1152 return make_user_everybody_admin_security_attr(umask, emask, amask);
1153 }
1154
1155 // method to create the security attributes structure for restricting
1156 // access to the shared memory backing store file.
1157 //
1158 // the caller must free the resources associated with the security
1159 // attributes structure created by this method by calling the
1160 // free_security_attr() method.
1161 //
1162 static LPSECURITY_ATTRIBUTES make_file_security_attr() {
1163
1164 // create extensive access rights for the user/owner of the file
1165 // and attribute read-only access rights for everybody else. This
1166 // is effectively equivalent to UNIX 600 permissions on a file.
1167 //
1168 DWORD umask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1169 DWORD emask = STANDARD_RIGHTS_READ | FILE_READ_ATTRIBUTES |
1170 FILE_READ_EA | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1171 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1172
1173 return make_user_everybody_admin_security_attr(umask, emask, amask);
1174 }
1175
1176 // method to create the security attributes structure for restricting
1177 // access to the name shared memory file mapping object.
1178 //
1179 // the caller must free the resources associated with the security
1180 // attributes structure created by this method by calling the
1181 // free_security_attr() method.
1182 //
1183 static LPSECURITY_ATTRIBUTES make_smo_security_attr() {
1184
1185 // create extensive access rights for the user/owner of the shared
1186 // memory object and attribute read-only access rights for everybody
1187 // else. This is effectively equivalent to UNIX 600 permissions on
1188 // on the shared memory object.
1189 //
1190 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_MAP_ALL_ACCESS;
1191 DWORD emask = STANDARD_RIGHTS_READ; // attributes only
1192 DWORD amask = STANDARD_RIGHTS_ALL | FILE_MAP_ALL_ACCESS;
1193
1194 return make_user_everybody_admin_security_attr(umask, emask, amask);
1195 }
1196
1197 // make the user specific temporary directory
1198 //
1199 static bool make_user_tmp_dir(const char* dirname) {
1200
1201
1202 LPSECURITY_ATTRIBUTES pDirSA = make_tmpdir_security_attr();
1203 if (pDirSA == NULL) {
1204 return false;
1205 }
1206
1207
1208 // create the directory with the given security attributes
1209 if (!CreateDirectory(dirname, pDirSA)) {
1210 DWORD lasterror = GetLastError();
1211 if (lasterror == ERROR_ALREADY_EXISTS) {
1212 // The directory already exists and was probably created by another
1213 // JVM instance. However, this could also be the result of a
1214 // deliberate symlink. Verify that the existing directory is safe.
1215 //
1216 if (!is_directory_secure(dirname)) {
1217 // directory is not secure
1218 if (PrintMiscellaneous && Verbose) {
1219 warning("%s directory is insecure\n", dirname);
1220 }
1221 return false;
1222 }
1223 // The administrator should be able to delete this directory.
1224 // But the directory created by previous version of JVM may not
1225 // have permission for administrators to delete this directory.
1226 // So add full permission to the administrator. Also setting new
1227 // DACLs might fix the corrupted the DACLs.
1228 SECURITY_INFORMATION secInfo = DACL_SECURITY_INFORMATION;
1229 if (!SetFileSecurity(dirname, secInfo, pDirSA->lpSecurityDescriptor)) {
1230 if (PrintMiscellaneous && Verbose) {
1231 lasterror = GetLastError();
1232 warning("SetFileSecurity failed for %s directory. lasterror %d \n",
1233 dirname, lasterror);
1234 }
1235 }
1236 }
1237 else {
1238 if (PrintMiscellaneous && Verbose) {
1239 warning("CreateDirectory failed: %d\n", GetLastError());
1240 }
1241 return false;
1242 }
1243 }
1244
1245 // free the security attributes structure
1246 free_security_attr(pDirSA);
1247
1248 return true;
1249 }
1250
1251 // create the shared memory resources
1252 //
1253 // This function creates the shared memory resources. This includes
1254 // the backing store file and the file mapping shared memory object.
1255 //
1256 static HANDLE create_sharedmem_resources(const char* dirname, const char* filename, const char* objectname, size_t size) {
1257
1258 HANDLE fh = INVALID_HANDLE_VALUE;
1259 HANDLE fmh = NULL;
1260
1261
1262 // create the security attributes for the backing store file
1263 LPSECURITY_ATTRIBUTES lpFileSA = make_file_security_attr();
1264 if (lpFileSA == NULL) {
1265 return NULL;
1266 }
1267
1268 // create the security attributes for the shared memory object
1269 LPSECURITY_ATTRIBUTES lpSmoSA = make_smo_security_attr();
1270 if (lpSmoSA == NULL) {
1271 free_security_attr(lpFileSA);
1272 return NULL;
1273 }
1274
1275 // create the user temporary directory
1276 if (!make_user_tmp_dir(dirname)) {
1277 // could not make/find the directory or the found directory
1278 // was not secure
1279 return NULL;
1280 }
1281
1282 // Create the file - the FILE_FLAG_DELETE_ON_CLOSE flag allows the
1283 // file to be deleted by the last process that closes its handle to
1284 // the file. This is important as the apis do not allow a terminating
1285 // JVM being monitored by another process to remove the file name.
1286 //
1287 // the FILE_SHARE_DELETE share mode is valid only in winnt
1288 //
1289 fh = CreateFile(
1290 filename, /* LPCTSTR file name */
1291
1292 GENERIC_READ|GENERIC_WRITE, /* DWORD desired access */
1293
1294 (os::win32::is_nt() ? FILE_SHARE_DELETE : 0)|
1295 FILE_SHARE_READ, /* DWORD share mode, future READONLY
1296 * open operations allowed
1297 */
1298 lpFileSA, /* LPSECURITY security attributes */
1299 CREATE_ALWAYS, /* DWORD creation disposition
1300 * create file, if it already
1301 * exists, overwrite it.
1302 */
1303 FILE_FLAG_DELETE_ON_CLOSE, /* DWORD flags and attributes */
1304
1305 NULL); /* HANDLE template file access */
1306
1307 free_security_attr(lpFileSA);
1308
1309 if (fh == INVALID_HANDLE_VALUE) {
1310 DWORD lasterror = GetLastError();
1311 if (PrintMiscellaneous && Verbose) {
1312 warning("could not create file %s: %d\n", filename, lasterror);
1313 }
1314 return NULL;
1315 }
1316
1317 // try to create the file mapping
1318 fmh = create_file_mapping(objectname, fh, lpSmoSA, size);
1319
1320 free_security_attr(lpSmoSA);
1321
1322 if (fmh == NULL) {
1323 // closing the file handle here will decrement the reference count
1324 // on the file. When all processes accessing the file close their
1325 // handle to it, the reference count will decrement to 0 and the
1326 // OS will delete the file. These semantics are requested by the
1327 // FILE_FLAG_DELETE_ON_CLOSE flag in CreateFile call above.
1328 CloseHandle(fh);
1329 fh = NULL;
1330 return NULL;
1331 }
1332
1333 // the file has been successfully created and the file mapping
1334 // object has been created.
1335 sharedmem_fileHandle = fh;
1336 sharedmem_fileName = strdup(filename);
1337
1338 return fmh;
1339 }
1340
1341 // open the shared memory object for the given vmid.
1342 //
1343 static HANDLE open_sharedmem_object(const char* objectname, DWORD ofm_access, TRAPS) {
1344
1345 HANDLE fmh;
1346
1347 // open the file mapping with the requested mode
1348 fmh = OpenFileMapping(
1349 ofm_access, /* DWORD access mode */
1350 FALSE, /* BOOL inherit flag - Do not allow inherit */
1351 objectname); /* name for object */
1352
1353 if (fmh == NULL) {
1354 if (PrintMiscellaneous && Verbose) {
1355 warning("OpenFileMapping failed for shared memory object %s:"
1356 " lasterror = %d\n", objectname, GetLastError());
1357 }
1358 THROW_MSG_(vmSymbols::java_lang_Exception(),
1359 "Could not open PerfMemory", INVALID_HANDLE_VALUE);
1360 }
1361
1362 return fmh;;
1363 }
1364
1365 // create a named shared memory region
1366 //
1367 // On Win32, a named shared memory object has a name space that
1368 // is independent of the file system name space. Shared memory object,
1369 // or more precisely, file mapping objects, provide no mechanism to
1370 // inquire the size of the memory region. There is also no api to
1371 // enumerate the memory regions for various processes.
1372 //
1373 // This implementation utilizes the shared memory name space in parallel
1374 // with the file system name space. This allows us to determine the
1375 // size of the shared memory region from the size of the file and it
1376 // allows us to provide a common, file system based name space for
1377 // shared memory across platforms.
1378 //
1379 static char* mapping_create_shared(size_t size) {
1380
1381 void *mapAddress;
1382 int vmid = os::current_process_id();
1383
1384 // get the name of the user associated with this process
1385 char* user = get_user_name();
1386
1387 if (user == NULL) {
1388 return NULL;
1389 }
1390
1391 // construct the name of the user specific temporary directory
1392 char* dirname = get_user_tmp_dir(user);
1393
1394 // check that the file system is secure - i.e. it supports ACLs.
1395 if (!is_filesystem_secure(dirname)) {
1396 return NULL;
1397 }
1398
1399 // create the names of the backing store files and for the
1400 // share memory object.
1401 //
1402 char* filename = get_sharedmem_filename(dirname, vmid);
1403 char* objectname = get_sharedmem_objectname(user, vmid);
1404
1405 // cleanup any stale shared memory resources
1406 cleanup_sharedmem_resources(dirname);
1407
1408 assert(((size != 0) && (size % os::vm_page_size() == 0)),
1409 "unexpected PerfMemry region size");
1410
1411 FREE_C_HEAP_ARRAY(char, user);
1412
1413 // create the shared memory resources
1414 sharedmem_fileMapHandle =
1415 create_sharedmem_resources(dirname, filename, objectname, size);
1416
1417 FREE_C_HEAP_ARRAY(char, filename);
1418 FREE_C_HEAP_ARRAY(char, objectname);
1419 FREE_C_HEAP_ARRAY(char, dirname);
1420
1421 if (sharedmem_fileMapHandle == NULL) {
1422 return NULL;
1423 }
1424
1425 // map the file into the address space
1426 mapAddress = MapViewOfFile(
1427 sharedmem_fileMapHandle, /* HANDLE = file mapping object */
1428 FILE_MAP_ALL_ACCESS, /* DWORD access flags */
1429 0, /* DWORD High word of offset */
1430 0, /* DWORD Low word of offset */
1431 (DWORD)size); /* DWORD Number of bytes to map */
1432
1433 if (mapAddress == NULL) {
1434 if (PrintMiscellaneous && Verbose) {
1435 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1436 }
1437 CloseHandle(sharedmem_fileMapHandle);
1438 sharedmem_fileMapHandle = NULL;
1439 return NULL;
1440 }
1441
1442 // clear the shared memory region
1443 (void)memset(mapAddress, '\0', size);
1444
1445 return (char*) mapAddress;
1446 }
1447
1448 // this method deletes the file mapping object.
1449 //
1450 static void delete_file_mapping(char* addr, size_t size) {
1451
1452 // cleanup the persistent shared memory resources. since DestroyJavaVM does
1453 // not support unloading of the JVM, unmapping of the memory resource is not
1454 // performed. The memory will be reclaimed by the OS upon termination of all
1455 // processes mapping the resource. The file mapping handle and the file
1456 // handle are closed here to expedite the remove of the file by the OS. The
1457 // file is not removed directly because it was created with
1458 // FILE_FLAG_DELETE_ON_CLOSE semantics and any attempt to remove it would
1459 // be unsuccessful.
1460
1461 // close the fileMapHandle. the file mapping will still be retained
1462 // by the OS as long as any other JVM processes has an open file mapping
1463 // handle or a mapped view of the file.
1464 //
1465 if (sharedmem_fileMapHandle != NULL) {
1466 CloseHandle(sharedmem_fileMapHandle);
1467 sharedmem_fileMapHandle = NULL;
1468 }
1469
1470 // close the file handle. This will decrement the reference count on the
1471 // backing store file. When the reference count decrements to 0, the OS
1472 // will delete the file. These semantics apply because the file was
1473 // created with the FILE_FLAG_DELETE_ON_CLOSE flag.
1474 //
1475 if (sharedmem_fileHandle != INVALID_HANDLE_VALUE) {
1476 CloseHandle(sharedmem_fileHandle);
1477 sharedmem_fileHandle = INVALID_HANDLE_VALUE;
1478 }
1479 }
1480
1481 // this method determines the size of the shared memory file
1482 //
1483 static size_t sharedmem_filesize(const char* filename, TRAPS) {
1484
1485 struct stat statbuf;
1486
1487 // get the file size
1488 //
1489 // on win95/98/me, _stat returns a file size of 0 bytes, but on
1490 // winnt/2k the appropriate file size is returned. support for
1491 // the sharable aspects of performance counters was abandonded
1492 // on the non-nt win32 platforms due to this and other api
1493 // inconsistencies
1494 //
1495 if (::stat(filename, &statbuf) == OS_ERR) {
1496 if (PrintMiscellaneous && Verbose) {
1497 warning("stat %s failed: %s\n", filename, strerror(errno));
1498 }
1499 THROW_MSG_0(vmSymbols::java_io_IOException(),
1500 "Could not determine PerfMemory size");
1501 }
1502
1503 if ((statbuf.st_size == 0) || (statbuf.st_size % os::vm_page_size() != 0)) {
1504 if (PrintMiscellaneous && Verbose) {
1505 warning("unexpected file size: size = " SIZE_FORMAT "\n",
1506 statbuf.st_size);
1507 }
1508 THROW_MSG_0(vmSymbols::java_lang_Exception(),
1509 "Invalid PerfMemory size");
1510 }
1511
1512 return statbuf.st_size;
1513 }
1514
1515 // this method opens a file mapping object and maps the object
1516 // into the address space of the process
1517 //
1518 static void open_file_mapping(const char* user, int vmid,
1519 PerfMemory::PerfMemoryMode mode,
1520 char** addrp, size_t* sizep, TRAPS) {
1521
1522 ResourceMark rm;
1523
1524 void *mapAddress = 0;
1525 size_t size;
1526 HANDLE fmh;
1527 DWORD ofm_access;
1528 DWORD mv_access;
1529 const char* luser = NULL;
1530
1531 if (mode == PerfMemory::PERF_MODE_RO) {
1532 ofm_access = FILE_MAP_READ;
1533 mv_access = FILE_MAP_READ;
1534 }
1535 else if (mode == PerfMemory::PERF_MODE_RW) {
1536 #ifdef LATER
1537 ofm_access = FILE_MAP_READ | FILE_MAP_WRITE;
1538 mv_access = FILE_MAP_READ | FILE_MAP_WRITE;
1539 #else
1540 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1541 "Unsupported access mode");
1542 #endif
1543 }
1544 else {
1545 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1546 "Illegal access mode");
1547 }
1548
1549 // if a user name wasn't specified, then find the user name for
1550 // the owner of the target vm.
1551 if (user == NULL || strlen(user) == 0) {
1552 luser = get_user_name(vmid);
1553 }
1554 else {
1555 luser = user;
1556 }
1557
1558 if (luser == NULL) {
1559 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1560 "Could not map vmid to user name");
1561 }
1562
1563 // get the names for the resources for the target vm
1564 char* dirname = get_user_tmp_dir(luser);
1565
1566 // since we don't follow symbolic links when creating the backing
1567 // store file, we also don't following them when attaching
1568 //
1569 if (!is_directory_secure(dirname)) {
1570 FREE_C_HEAP_ARRAY(char, dirname);
1571 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1572 "Process not found");
1573 }
1574
1575 char* filename = get_sharedmem_filename(dirname, vmid);
1576 char* objectname = get_sharedmem_objectname(luser, vmid);
1577
1578 // copy heap memory to resource memory. the objectname and
1579 // filename are passed to methods that may throw exceptions.
1580 // using resource arrays for these names prevents the leaks
1581 // that would otherwise occur.
1582 //
1583 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
1584 char* robjectname = NEW_RESOURCE_ARRAY(char, strlen(objectname) + 1);
1585 strcpy(rfilename, filename);
1586 strcpy(robjectname, objectname);
1587
1588 // free the c heap resources that are no longer needed
1589 if (luser != user) FREE_C_HEAP_ARRAY(char, luser);
1590 FREE_C_HEAP_ARRAY(char, dirname);
1591 FREE_C_HEAP_ARRAY(char, filename);
1592 FREE_C_HEAP_ARRAY(char, objectname);
1593
1594 if (*sizep == 0) {
1595 size = sharedmem_filesize(rfilename, CHECK);
1596 assert(size != 0, "unexpected size");
1597 }
1598
1599 // Open the file mapping object with the given name
1600 fmh = open_sharedmem_object(robjectname, ofm_access, CHECK);
1601
1602 assert(fmh != INVALID_HANDLE_VALUE, "unexpected handle value");
1603
1604 // map the entire file into the address space
1605 mapAddress = MapViewOfFile(
1606 fmh, /* HANDLE Handle of file mapping object */
1607 mv_access, /* DWORD access flags */
1608 0, /* DWORD High word of offset */
1609 0, /* DWORD Low word of offset */
1610 size); /* DWORD Number of bytes to map */
1611
1612 if (mapAddress == NULL) {
1613 if (PrintMiscellaneous && Verbose) {
1614 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1615 }
1616 CloseHandle(fmh);
1617 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
1618 "Could not map PerfMemory");
1619 }
1620
1621 *addrp = (char*)mapAddress;
1622 *sizep = size;
1623
1624 // File mapping object can be closed at this time without
1625 // invalidating the mapped view of the file
1626 CloseHandle(fmh);
1627
1628 if (PerfTraceMemOps) {
1629 tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
1630 INTPTR_FORMAT "\n", size, vmid, mapAddress);
1631 }
1632 }
1633
1634 // this method unmaps the the mapped view of the the
1635 // file mapping object.
1636 //
1637 static void remove_file_mapping(char* addr) {
1638
1639 // the file mapping object was closed in open_file_mapping()
1640 // after the file map view was created. We only need to
1641 // unmap the file view here.
1642 UnmapViewOfFile(addr);
1643 }
1644
1645 // create the PerfData memory region in shared memory.
1646 static char* create_shared_memory(size_t size) {
1647
1648 return mapping_create_shared(size);
1649 }
1650
1651 // release a named, shared memory region
1652 //
1653 void delete_shared_memory(char* addr, size_t size) {
1654
1655 delete_file_mapping(addr, size);
1656 }
1657
1658
1659
1660
1661 // create the PerfData memory region
1662 //
1663 // This method creates the memory region used to store performance
1664 // data for the JVM. The memory may be created in standard or
1665 // shared memory.
1666 //
1667 void PerfMemory::create_memory_region(size_t size) {
1668
1669 if (PerfDisableSharedMem || !os::win32::is_nt()) {
1670 // do not share the memory for the performance data.
1671 PerfDisableSharedMem = true;
1672 _start = create_standard_memory(size);
1673 }
1674 else {
1675 _start = create_shared_memory(size);
1676 if (_start == NULL) {
1677
1678 // creation of the shared memory region failed, attempt
1679 // to create a contiguous, non-shared memory region instead.
1680 //
1681 if (PrintMiscellaneous && Verbose) {
1682 warning("Reverting to non-shared PerfMemory region.\n");
1683 }
1684 PerfDisableSharedMem = true;
1685 _start = create_standard_memory(size);
1686 }
1687 }
1688
1689 if (_start != NULL) _capacity = size;
1690
1691 }
1692
1693 // delete the PerfData memory region
1694 //
1695 // This method deletes the memory region used to store performance
1696 // data for the JVM. The memory region indicated by the <address, size>
1697 // tuple will be inaccessible after a call to this method.
1698 //
1699 void PerfMemory::delete_memory_region() {
1700
1701 assert((start() != NULL && capacity() > 0), "verify proper state");
1702
1703 // If user specifies PerfDataSaveFile, it will save the performance data
1704 // to the specified file name no matter whether PerfDataSaveToFile is specified
1705 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
1706 // -XX:+PerfDataSaveToFile.
1707 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
1708 save_memory_to_file(start(), capacity());
1709 }
1710
1711 if (PerfDisableSharedMem) {
1712 delete_standard_memory(start(), capacity());
1713 }
1714 else {
1715 delete_shared_memory(start(), capacity());
1716 }
1717 }
1718
1719 // attach to the PerfData memory region for another JVM
1720 //
1721 // This method returns an <address, size> tuple that points to
1722 // a memory buffer that is kept reasonably synchronized with
1723 // the PerfData memory region for the indicated JVM. This
1724 // buffer may be kept in synchronization via shared memory
1725 // or some other mechanism that keeps the buffer updated.
1726 //
1727 // If the JVM chooses not to support the attachability feature,
1728 // this method should throw an UnsupportedOperation exception.
1729 //
1730 // This implementation utilizes named shared memory to map
1731 // the indicated process's PerfData memory region into this JVMs
1732 // address space.
1733 //
1734 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode,
1735 char** addrp, size_t* sizep, TRAPS) {
1736
1737 if (vmid == 0 || vmid == os::current_process_id()) {
1738 *addrp = start();
1739 *sizep = capacity();
1740 return;
1741 }
1742
1743 open_file_mapping(user, vmid, mode, addrp, sizep, CHECK);
1744 }
1745
1746 // detach from the PerfData memory region of another JVM
1747 //
1748 // This method detaches the PerfData memory region of another
1749 // JVM, specified as an <address, size> tuple of a buffer
1750 // in this process's address space. This method may perform
1751 // arbitrary actions to accomplish the detachment. The memory
1752 // region specified by <address, size> will be inaccessible after
1753 // a call to this method.
1754 //
1755 // If the JVM chooses not to support the attachability feature,
1756 // this method should throw an UnsupportedOperation exception.
1757 //
1758 // This implementation utilizes named shared memory to detach
1759 // the indicated process's PerfData memory region from this
1760 // process's address space.
1761 //
1762 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
1763
1764 assert(addr != 0, "address sanity check");
1765 assert(bytes > 0, "capacity sanity check");
1766
1767 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
1768 // prevent accidental detachment of this process's PerfMemory region
1769 return;
1770 }
1771
1772 remove_file_mapping(addr);
1773 }
1774
1775 char* PerfMemory::backing_store_filename() {
1776 return sharedmem_fileName;
1777 }