1 /*
2 * Copyright (c) 2001, 2010, 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 "utilities/exceptions.hpp"
34
35 #include <windows.h>
36 #include <sys/types.h>
37 #include <sys/stat.h>
38 #include <errno.h>
39 #include <lmcons.h>
40
41 typedef BOOL (WINAPI *SetSecurityDescriptorControlFnPtr)(
42 IN PSECURITY_DESCRIPTOR pSecurityDescriptor,
43 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsOfInterest,
44 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsToSet);
45
46 // Standard Memory Implementation Details
47
48 // create the PerfData memory region in standard memory.
49 //
50 static char* create_standard_memory(size_t size) {
51
52 // allocate an aligned chuck of memory
53 char* mapAddress = os::reserve_memory(size);
54
55 if (mapAddress == NULL) {
56 return NULL;
57 }
58
59 // commit memory
60 if (!os::commit_memory(mapAddress, size)) {
61 if (PrintMiscellaneous && Verbose) {
62 warning("Could not commit PerfData memory\n");
63 }
64 os::release_memory(mapAddress, size);
65 return NULL;
66 }
67
68 return mapAddress;
69 }
70
71 // delete the PerfData memory region
72 //
73 static void delete_standard_memory(char* addr, size_t size) {
74
75 // there are no persistent external resources to cleanup for standard
76 // memory. since DestroyJavaVM does not support unloading of the JVM,
77 // cleanup of the memory resource is not performed. The memory will be
78 // reclaimed by the OS upon termination of the process.
79 //
80 return;
81
82 }
83
84 // save the specified memory region to the given file
85 //
86 static void save_memory_to_file(char* addr, size_t size) {
87
88 const char* destfile = PerfMemory::get_perfdata_file_path();
89 assert(destfile[0] != '\0', "invalid Perfdata file path");
90
91 int fd = ::_open(destfile, _O_BINARY|_O_CREAT|_O_WRONLY|_O_TRUNC,
92 _S_IREAD|_S_IWRITE);
93
94 if (fd == OS_ERR) {
95 if (PrintMiscellaneous && Verbose) {
96 warning("Could not create Perfdata save file: %s: %s\n",
97 destfile, strerror(errno));
98 }
99 } else {
100 for (size_t remaining = size; remaining > 0;) {
101
102 int nbytes = ::_write(fd, addr, (unsigned int)remaining);
103 if (nbytes == OS_ERR) {
104 if (PrintMiscellaneous && Verbose) {
105 warning("Could not write Perfdata save file: %s: %s\n",
106 destfile, strerror(errno));
107 }
108 break;
109 }
110
111 remaining -= (size_t)nbytes;
112 addr += nbytes;
113 }
114
115 int result = ::_close(fd);
116 if (PrintMiscellaneous && Verbose) {
117 if (result == OS_ERR) {
118 warning("Could not close %s: %s\n", destfile, strerror(errno));
119 }
120 }
121 }
122
123 FREE_C_HEAP_ARRAY(char, destfile);
124 }
125
126 // Shared Memory Implementation Details
127
128 // Note: the win32 shared memory implementation uses two objects to represent
129 // the shared memory: a windows kernel based file mapping object and a backing
130 // store file. On windows, the name space for shared memory is a kernel
131 // based name space that is disjoint from other win32 name spaces. Since Java
132 // is unaware of this name space, a parallel file system based name space is
133 // maintained, which provides a common file system based shared memory name
134 // space across the supported platforms and one that Java apps can deal with
135 // through simple file apis.
136 //
137 // For performance and resource cleanup reasons, it is recommended that the
138 // user specific directory and the backing store file be stored in either a
139 // RAM based file system or a local disk based file system. Network based
140 // file systems are not recommended for performance reasons. In addition,
141 // use of SMB network based file systems may result in unsuccesful cleanup
142 // of the disk based resource on exit of the VM. The Windows TMP and TEMP
143 // environement variables, as used by the GetTempPath() Win32 API (see
144 // os::get_temp_directory() in os_win32.cpp), control the location of the
145 // user specific directory and the shared memory backing store file.
146
147 static HANDLE sharedmem_fileMapHandle = NULL;
148 static HANDLE sharedmem_fileHandle = INVALID_HANDLE_VALUE;
149 static char* sharedmem_fileName = NULL;
150
151 // return the user specific temporary directory name.
152 //
153 // the caller is expected to free the allocated memory.
154 //
155 static char* get_user_tmp_dir(const char* user) {
156
157 const char* tmpdir = os::get_temp_directory();
158 const char* perfdir = PERFDATA_NAME;
159 size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
160 char* dirname = NEW_C_HEAP_ARRAY(char, nbytes);
161
162 // construct the path name to user specific tmp directory
163 _snprintf(dirname, nbytes, "%s\\%s_%s", tmpdir, perfdir, user);
164
165 return dirname;
166 }
167
168 // convert the given file name into a process id. if the file
169 // does not meet the file naming constraints, return 0.
170 //
171 static int filename_to_pid(const char* filename) {
172
173 // a filename that doesn't begin with a digit is not a
174 // candidate for conversion.
175 //
176 if (!isdigit(*filename)) {
177 return 0;
178 }
179
180 // check if file name can be converted to an integer without
181 // any leftover characters.
182 //
183 char* remainder = NULL;
184 errno = 0;
185 int pid = (int)strtol(filename, &remainder, 10);
186
187 if (errno != 0) {
188 return 0;
189 }
190
191 // check for left over characters. If any, then the filename is
192 // not a candidate for conversion.
193 //
194 if (remainder != NULL && *remainder != '\0') {
195 return 0;
196 }
197
198 // successful conversion, return the pid
199 return pid;
200 }
201
202 // check if the given path is considered a secure directory for
203 // the backing store files. Returns true if the directory exists
204 // and is considered a secure location. Returns false if the path
205 // is a symbolic link or if an error occurred.
206 //
207 static bool is_directory_secure(const char* path) {
208
209 DWORD fa;
210
211 fa = GetFileAttributes(path);
212 if (fa == 0xFFFFFFFF) {
213 DWORD lasterror = GetLastError();
214 if (lasterror == ERROR_FILE_NOT_FOUND) {
215 return false;
216 }
217 else {
218 // unexpected error, declare the path insecure
219 if (PrintMiscellaneous && Verbose) {
220 warning("could not get attributes for file %s: ",
221 " lasterror = %d\n", path, lasterror);
222 }
223 return false;
224 }
225 }
226
227 if (fa & FILE_ATTRIBUTE_REPARSE_POINT) {
228 // we don't accept any redirection for the user specific directory
229 // so declare the path insecure. This may be too conservative,
230 // as some types of reparse points might be acceptable, but it
231 // is probably more secure to avoid these conditions.
232 //
233 if (PrintMiscellaneous && Verbose) {
234 warning("%s is a reparse point\n", path);
235 }
236 return false;
237 }
238
239 if (fa & FILE_ATTRIBUTE_DIRECTORY) {
240 // this is the expected case. Since windows supports symbolic
241 // links to directories only, not to files, there is no need
242 // to check for open write permissions on the directory. If the
243 // directory has open write permissions, any files deposited that
244 // are not expected will be removed by the cleanup code.
245 //
246 return true;
247 }
248 else {
249 // this is either a regular file or some other type of file,
250 // any of which are unexpected and therefore insecure.
251 //
252 if (PrintMiscellaneous && Verbose) {
253 warning("%s is not a directory, file attributes = "
254 INTPTR_FORMAT "\n", path, fa);
255 }
256 return false;
257 }
258 }
259
260 // return the user name for the owner of this process
261 //
262 // the caller is expected to free the allocated memory.
263 //
264 static char* get_user_name() {
265
266 /* get the user name. This code is adapted from code found in
267 * the jdk in src/windows/native/java/lang/java_props_md.c
268 * java_props_md.c 1.29 02/02/06. According to the original
269 * source, the call to GetUserName is avoided because of a resulting
270 * increase in footprint of 100K.
271 */
272 char* user = getenv("USERNAME");
273 char buf[UNLEN+1];
274 DWORD buflen = sizeof(buf);
275 if (user == NULL || strlen(user) == 0) {
276 if (GetUserName(buf, &buflen)) {
277 user = buf;
278 }
279 else {
280 return NULL;
281 }
282 }
283
284 char* user_name = NEW_C_HEAP_ARRAY(char, strlen(user)+1);
285 strcpy(user_name, user);
286
287 return user_name;
288 }
289
290 // return the name of the user that owns the process identified by vmid.
291 //
292 // This method uses a slow directory search algorithm to find the backing
293 // store file for the specified vmid and returns the user name, as determined
294 // by the user name suffix of the hsperfdata_<username> directory name.
295 //
296 // the caller is expected to free the allocated memory.
297 //
298 static char* get_user_name_slow(int vmid) {
299
300 // directory search
301 char* oldest_user = NULL;
302 time_t oldest_ctime = 0;
303
304 const char* tmpdirname = os::get_temp_directory();
305
306 DIR* tmpdirp = os::opendir(tmpdirname);
307
308 if (tmpdirp == NULL) {
309 return NULL;
310 }
311
312 // for each entry in the directory that matches the pattern hsperfdata_*,
313 // open the directory and check if the file for the given vmid exists.
314 // The file with the expected name and the latest creation date is used
315 // to determine the user name for the process id.
316 //
317 struct dirent* dentry;
318 char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname));
319 errno = 0;
320 while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != 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);
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);
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);
348 os::closedir(subdirp);
349 continue;
350 }
351
352 struct dirent* udentry;
353 char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name));
354 errno = 0;
355 while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
356
357 if (filename_to_pid(udentry->d_name) == vmid) {
358 struct stat statbuf;
359
360 char* filename = NEW_C_HEAP_ARRAY(char,
361 strlen(usrdir_name) + strlen(udentry->d_name) + 2);
362
363 strcpy(filename, usrdir_name);
364 strcat(filename, "\\");
365 strcat(filename, udentry->d_name);
366
367 if (::stat(filename, &statbuf) == OS_ERR) {
368 FREE_C_HEAP_ARRAY(char, filename);
369 continue;
370 }
371
372 // skip over files that are not regular files.
373 if ((statbuf.st_mode & S_IFMT) != S_IFREG) {
374 FREE_C_HEAP_ARRAY(char, filename);
375 continue;
376 }
377
378 // compare and save filename with latest creation time
379 if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
380
381 if (statbuf.st_ctime > oldest_ctime) {
382 char* user = strchr(dentry->d_name, '_') + 1;
383
384 if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user);
385 oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1);
386
387 strcpy(oldest_user, user);
388 oldest_ctime = statbuf.st_ctime;
389 }
390 }
391
392 FREE_C_HEAP_ARRAY(char, filename);
393 }
394 }
395 os::closedir(subdirp);
396 FREE_C_HEAP_ARRAY(char, udbuf);
397 FREE_C_HEAP_ARRAY(char, usrdir_name);
398 }
399 os::closedir(tmpdirp);
400 FREE_C_HEAP_ARRAY(char, tdbuf);
401
402 return(oldest_user);
403 }
404
405 // return the name of the user that owns the process identified by vmid.
406 //
407 // note: this method should only be used via the Perf native methods.
408 // There are various costs to this method and limiting its use to the
409 // Perf native methods limits the impact to monitoring applications only.
410 //
411 static char* get_user_name(int vmid) {
412
413 // A fast implementation is not provided at this time. It's possible
414 // to provide a fast process id to user name mapping function using
415 // the win32 apis, but the default ACL for the process object only
416 // allows processes with the same owner SID to acquire the process
417 // handle (via OpenProcess(PROCESS_QUERY_INFORMATION)). It's possible
418 // to have the JVM change the ACL for the process object to allow arbitrary
419 // users to access the process handle and the process security token.
420 // The security ramifications need to be studied before providing this
421 // mechanism.
422 //
423 return get_user_name_slow(vmid);
424 }
425
426 // return the name of the shared memory file mapping object for the
427 // named shared memory region for the given user name and vmid.
428 //
429 // The file mapping object's name is not the file name. It is a name
430 // in a separate name space.
431 //
432 // the caller is expected to free the allocated memory.
433 //
434 static char *get_sharedmem_objectname(const char* user, int vmid) {
435
436 // construct file mapping object's name, add 3 for two '_' and a
437 // null terminator.
438 int nbytes = (int)strlen(PERFDATA_NAME) + (int)strlen(user) + 3;
439
440 // the id is converted to an unsigned value here because win32 allows
441 // negative process ids. However, OpenFileMapping API complains
442 // about a name containing a '-' characters.
443 //
444 nbytes += UINT_CHARS;
445 char* name = NEW_C_HEAP_ARRAY(char, nbytes);
446 _snprintf(name, nbytes, "%s_%s_%u", PERFDATA_NAME, user, vmid);
447
448 return name;
449 }
450
451 // return the file name of the backing store file for the named
452 // shared memory region for the given user name and vmid.
453 //
454 // the caller is expected to free the allocated memory.
455 //
456 static char* get_sharedmem_filename(const char* dirname, int vmid) {
457
458 // add 2 for the file separator and a null terminator.
459 size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
460
461 char* name = NEW_C_HEAP_ARRAY(char, nbytes);
462 _snprintf(name, nbytes, "%s\\%d", dirname, vmid);
463
464 return name;
465 }
466
467 // remove file
468 //
469 // this method removes the file with the given file name.
470 //
471 // Note: if the indicated file is on an SMB network file system, this
472 // method may be unsuccessful in removing the file.
473 //
474 static void remove_file(const char* dirname, const char* filename) {
475
476 size_t nbytes = strlen(dirname) + strlen(filename) + 2;
477 char* path = NEW_C_HEAP_ARRAY(char, nbytes);
478
479 strcpy(path, dirname);
480 strcat(path, "\\");
481 strcat(path, filename);
482
483 if (::unlink(path) == OS_ERR) {
484 if (PrintMiscellaneous && Verbose) {
485 if (errno != ENOENT) {
486 warning("Could not unlink shared memory backing"
487 " store file %s : %s\n", path, strerror(errno));
488 }
489 }
490 }
491
492 FREE_C_HEAP_ARRAY(char, path);
493 }
494
495 // returns true if the process represented by pid is alive, otherwise
496 // returns false. the validity of the result is only accurate if the
497 // target process is owned by the same principal that owns this process.
498 // this method should not be used if to test the status of an otherwise
499 // arbitrary process unless it is know that this process has the appropriate
500 // privileges to guarantee a result valid.
501 //
502 static bool is_alive(int pid) {
503
504 HANDLE ph = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);
505 if (ph == NULL) {
506 // the process does not exist.
507 if (PrintMiscellaneous && Verbose) {
508 DWORD lastError = GetLastError();
509 if (lastError != ERROR_INVALID_PARAMETER) {
510 warning("OpenProcess failed: %d\n", GetLastError());
511 }
512 }
513 return false;
514 }
515
516 DWORD exit_status;
517 if (!GetExitCodeProcess(ph, &exit_status)) {
518 if (PrintMiscellaneous && Verbose) {
519 warning("GetExitCodeProcess failed: %d\n", GetLastError());
520 }
521 CloseHandle(ph);
522 return false;
523 }
524
525 CloseHandle(ph);
526 return (exit_status == STILL_ACTIVE) ? true : false;
527 }
528
529 // check if the file system is considered secure for the backing store files
530 //
531 static bool is_filesystem_secure(const char* path) {
532
533 char root_path[MAX_PATH];
534 char fs_type[MAX_PATH];
535
536 if (PerfBypassFileSystemCheck) {
537 if (PrintMiscellaneous && Verbose) {
538 warning("bypassing file system criteria checks for %s\n", path);
539 }
540 return true;
541 }
542
543 char* first_colon = strchr((char *)path, ':');
544 if (first_colon == NULL) {
545 if (PrintMiscellaneous && Verbose) {
546 warning("expected device specifier in path: %s\n", path);
547 }
548 return false;
549 }
550
551 size_t len = (size_t)(first_colon - path);
552 assert(len + 2 <= MAX_PATH, "unexpected device specifier length");
553 strncpy(root_path, path, len + 1);
554 root_path[len + 1] = '\\';
555 root_path[len + 2] = '\0';
556
557 // check that we have something like "C:\" or "AA:\"
558 assert(strlen(root_path) >= 3, "device specifier too short");
559 assert(strchr(root_path, ':') != NULL, "bad device specifier format");
560 assert(strchr(root_path, '\\') != NULL, "bad device specifier format");
561
562 DWORD maxpath;
563 DWORD flags;
564
565 if (!GetVolumeInformation(root_path, NULL, 0, NULL, &maxpath,
566 &flags, fs_type, MAX_PATH)) {
567 // we can't get information about the volume, so assume unsafe.
568 if (PrintMiscellaneous && Verbose) {
569 warning("could not get device information for %s: "
570 " path = %s: lasterror = %d\n",
571 root_path, path, GetLastError());
572 }
573 return false;
574 }
575
576 if ((flags & FS_PERSISTENT_ACLS) == 0) {
577 // file system doesn't support ACLs, declare file system unsafe
578 if (PrintMiscellaneous && Verbose) {
579 warning("file system type %s on device %s does not support"
580 " ACLs\n", fs_type, root_path);
581 }
582 return false;
583 }
584
585 if ((flags & FS_VOL_IS_COMPRESSED) != 0) {
586 // file system is compressed, declare file system unsafe
587 if (PrintMiscellaneous && Verbose) {
588 warning("file system type %s on device %s is compressed\n",
589 fs_type, root_path);
590 }
591 return false;
592 }
593
594 return true;
595 }
596
597 // cleanup stale shared memory resources
598 //
599 // This method attempts to remove all stale shared memory files in
600 // the named user temporary directory. It scans the named directory
601 // for files matching the pattern ^$[0-9]*$. For each file found, the
602 // process id is extracted from the file name and a test is run to
603 // determine if the process is alive. If the process is not alive,
604 // any stale file resources are removed.
605 //
606 static void cleanup_sharedmem_resources(const char* dirname) {
607
608 // open the user temp directory
609 DIR* dirp = os::opendir(dirname);
610
611 if (dirp == NULL) {
612 // directory doesn't exist, so there is nothing to cleanup
613 return;
614 }
615
616 if (!is_directory_secure(dirname)) {
617 // the directory is not secure, don't attempt any cleanup
618 return;
619 }
620
621 // for each entry in the directory that matches the expected file
622 // name pattern, determine if the file resources are stale and if
623 // so, remove the file resources. Note, instrumented HotSpot processes
624 // for this user may start and/or terminate during this search and
625 // remove or create new files in this directory. The behavior of this
626 // loop under these conditions is dependent upon the implementation of
627 // opendir/readdir.
628 //
629 struct dirent* entry;
630 char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname));
631 errno = 0;
632 while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
633
634 int pid = filename_to_pid(entry->d_name);
635
636 if (pid == 0) {
637
638 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
639
640 // attempt to remove all unexpected files, except "." and ".."
641 remove_file(dirname, entry->d_name);
642 }
643
644 errno = 0;
645 continue;
646 }
647
648 // we now have a file name that converts to a valid integer
649 // that could represent a process id . if this process id
650 // matches the current process id or the process is not running,
651 // then remove the stale file resources.
652 //
653 // process liveness is detected by checking the exit status
654 // of the process. if the process id is valid and the exit status
655 // indicates that it is still running, the file file resources
656 // are not removed. If the process id is invalid, or if we don't
657 // have permissions to check the process status, or if the process
658 // id is valid and the process has terminated, the the file resources
659 // are assumed to be stale and are removed.
660 //
661 if (pid == os::current_process_id() || !is_alive(pid)) {
662
663 // we can only remove the file resources. Any mapped views
664 // of the file can only be unmapped by the processes that
665 // opened those views and the file mapping object will not
666 // get removed until all views are unmapped.
667 //
668 remove_file(dirname, entry->d_name);
669 }
670 errno = 0;
671 }
672 os::closedir(dirp);
673 FREE_C_HEAP_ARRAY(char, dbuf);
674 }
675
676 // create a file mapping object with the requested name, and size
677 // from the file represented by the given Handle object
678 //
679 static HANDLE create_file_mapping(const char* name, HANDLE fh, LPSECURITY_ATTRIBUTES fsa, size_t size) {
680
681 DWORD lowSize = (DWORD)size;
682 DWORD highSize = 0;
683 HANDLE fmh = NULL;
684
685 // Create a file mapping object with the given name. This function
686 // will grow the file to the specified size.
687 //
688 fmh = CreateFileMapping(
689 fh, /* HANDLE file handle for backing store */
690 fsa, /* LPSECURITY_ATTRIBUTES Not inheritable */
691 PAGE_READWRITE, /* DWORD protections */
692 highSize, /* DWORD High word of max size */
693 lowSize, /* DWORD Low word of max size */
694 name); /* LPCTSTR name for object */
695
696 if (fmh == NULL) {
697 if (PrintMiscellaneous && Verbose) {
698 warning("CreateFileMapping failed, lasterror = %d\n", GetLastError());
699 }
700 return NULL;
701 }
702
703 if (GetLastError() == ERROR_ALREADY_EXISTS) {
704
705 // a stale file mapping object was encountered. This object may be
706 // owned by this or some other user and cannot be removed until
707 // the other processes either exit or close their mapping objects
708 // and/or mapped views of this mapping object.
709 //
710 if (PrintMiscellaneous && Verbose) {
711 warning("file mapping already exists, lasterror = %d\n", GetLastError());
712 }
713
714 CloseHandle(fmh);
715 return NULL;
716 }
717
718 return fmh;
719 }
720
721
722 // method to free the given security descriptor and the contained
723 // access control list.
724 //
725 static void free_security_desc(PSECURITY_DESCRIPTOR pSD) {
726
727 BOOL success, exists, isdefault;
728 PACL pACL;
729
730 if (pSD != NULL) {
731
732 // get the access control list from the security descriptor
733 success = GetSecurityDescriptorDacl(pSD, &exists, &pACL, &isdefault);
734
735 // if an ACL existed and it was not a default acl, then it must
736 // be an ACL we enlisted. free the resources.
737 //
738 if (success && exists && pACL != NULL && !isdefault) {
739 FREE_C_HEAP_ARRAY(char, pACL);
740 }
741
742 // free the security descriptor
743 FREE_C_HEAP_ARRAY(char, pSD);
744 }
745 }
746
747 // method to free up a security attributes structure and any
748 // contained security descriptors and ACL
749 //
750 static void free_security_attr(LPSECURITY_ATTRIBUTES lpSA) {
751
752 if (lpSA != NULL) {
753 // free the contained security descriptor and the ACL
754 free_security_desc(lpSA->lpSecurityDescriptor);
755 lpSA->lpSecurityDescriptor = NULL;
756
757 // free the security attributes structure
758 FREE_C_HEAP_ARRAY(char, lpSA);
759 }
760 }
761
762 // get the user SID for the process indicated by the process handle
763 //
764 static PSID get_user_sid(HANDLE hProcess) {
765
766 HANDLE hAccessToken;
767 PTOKEN_USER token_buf = NULL;
768 DWORD rsize = 0;
769
770 if (hProcess == NULL) {
771 return NULL;
772 }
773
774 // get the process token
775 if (!OpenProcessToken(hProcess, TOKEN_READ, &hAccessToken)) {
776 if (PrintMiscellaneous && Verbose) {
777 warning("OpenProcessToken failure: lasterror = %d \n", GetLastError());
778 }
779 return NULL;
780 }
781
782 // determine the size of the token structured needed to retrieve
783 // the user token information from the access token.
784 //
785 if (!GetTokenInformation(hAccessToken, TokenUser, NULL, rsize, &rsize)) {
786 DWORD lasterror = GetLastError();
787 if (lasterror != ERROR_INSUFFICIENT_BUFFER) {
788 if (PrintMiscellaneous && Verbose) {
789 warning("GetTokenInformation failure: lasterror = %d,"
790 " rsize = %d\n", lasterror, rsize);
791 }
792 CloseHandle(hAccessToken);
793 return NULL;
794 }
795 }
796
797 token_buf = (PTOKEN_USER) NEW_C_HEAP_ARRAY(char, rsize);
798
799 // get the user token information
800 if (!GetTokenInformation(hAccessToken, TokenUser, token_buf, rsize, &rsize)) {
801 if (PrintMiscellaneous && Verbose) {
802 warning("GetTokenInformation failure: lasterror = %d,"
803 " rsize = %d\n", GetLastError(), rsize);
804 }
805 FREE_C_HEAP_ARRAY(char, token_buf);
806 CloseHandle(hAccessToken);
807 return NULL;
808 }
809
810 DWORD nbytes = GetLengthSid(token_buf->User.Sid);
811 PSID pSID = NEW_C_HEAP_ARRAY(char, nbytes);
812
813 if (!CopySid(nbytes, pSID, token_buf->User.Sid)) {
814 if (PrintMiscellaneous && Verbose) {
815 warning("GetTokenInformation failure: lasterror = %d,"
816 " rsize = %d\n", GetLastError(), rsize);
817 }
818 FREE_C_HEAP_ARRAY(char, token_buf);
819 FREE_C_HEAP_ARRAY(char, pSID);
820 CloseHandle(hAccessToken);
821 return NULL;
822 }
823
824 // close the access token.
825 CloseHandle(hAccessToken);
826 FREE_C_HEAP_ARRAY(char, token_buf);
827
828 return pSID;
829 }
830
831 // structure used to consolidate access control entry information
832 //
833 typedef struct ace_data {
834 PSID pSid; // SID of the ACE
835 DWORD mask; // mask for the ACE
836 } ace_data_t;
837
838
839 // method to add an allow access control entry with the access rights
840 // indicated in mask for the principal indicated in SID to the given
841 // security descriptor. Much of the DACL handling was adapted from
842 // the example provided here:
843 // http://support.microsoft.com/kb/102102/EN-US/
844 //
845
846 static bool add_allow_aces(PSECURITY_DESCRIPTOR pSD,
847 ace_data_t aces[], int ace_count) {
848 PACL newACL = NULL;
849 PACL oldACL = NULL;
850
851 if (pSD == NULL) {
852 return false;
853 }
854
855 BOOL exists, isdefault;
856
857 // retrieve any existing access control list.
858 if (!GetSecurityDescriptorDacl(pSD, &exists, &oldACL, &isdefault)) {
859 if (PrintMiscellaneous && Verbose) {
860 warning("GetSecurityDescriptor failure: lasterror = %d \n",
861 GetLastError());
862 }
863 return false;
864 }
865
866 // get the size of the DACL
867 ACL_SIZE_INFORMATION aclinfo;
868
869 // GetSecurityDescriptorDacl may return true value for exists (lpbDaclPresent)
870 // while oldACL is NULL for some case.
871 if (oldACL == NULL) {
872 exists = FALSE;
873 }
874
875 if (exists) {
876 if (!GetAclInformation(oldACL, &aclinfo,
877 sizeof(ACL_SIZE_INFORMATION),
878 AclSizeInformation)) {
879 if (PrintMiscellaneous && Verbose) {
880 warning("GetAclInformation failure: lasterror = %d \n", GetLastError());
881 return false;
882 }
883 }
884 } else {
885 aclinfo.AceCount = 0; // assume NULL DACL
886 aclinfo.AclBytesFree = 0;
887 aclinfo.AclBytesInUse = sizeof(ACL);
888 }
889
890 // compute the size needed for the new ACL
891 // initial size of ACL is sum of the following:
892 // * size of ACL structure.
893 // * size of each ACE structure that ACL is to contain minus the sid
894 // sidStart member (DWORD) of the ACE.
895 // * length of the SID that each ACE is to contain.
896 DWORD newACLsize = aclinfo.AclBytesInUse +
897 (sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD)) * ace_count;
898 for (int i = 0; i < ace_count; i++) {
899 assert(aces[i].pSid != 0, "pSid should not be 0");
900 newACLsize += GetLengthSid(aces[i].pSid);
901 }
902
903 // create the new ACL
904 newACL = (PACL) NEW_C_HEAP_ARRAY(char, newACLsize);
905
906 if (!InitializeAcl(newACL, newACLsize, ACL_REVISION)) {
907 if (PrintMiscellaneous && Verbose) {
908 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
909 }
910 FREE_C_HEAP_ARRAY(char, newACL);
911 return false;
912 }
913
914 unsigned int ace_index = 0;
915 // copy any existing ACEs from the old ACL (if any) to the new ACL.
916 if (aclinfo.AceCount != 0) {
917 while (ace_index < aclinfo.AceCount) {
918 LPVOID ace;
919 if (!GetAce(oldACL, ace_index, &ace)) {
920 if (PrintMiscellaneous && Verbose) {
921 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
922 }
923 FREE_C_HEAP_ARRAY(char, newACL);
924 return false;
925 }
926 if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceFlags && INHERITED_ACE) {
927 // this is an inherited, allowed ACE; break from loop so we can
928 // add the new access allowed, non-inherited ACE in the correct
929 // position, immediately following all non-inherited ACEs.
930 break;
931 }
932
933 // determine if the SID of this ACE matches any of the SIDs
934 // for which we plan to set ACEs.
935 int matches = 0;
936 for (int i = 0; i < ace_count; i++) {
937 if (EqualSid(aces[i].pSid, &(((ACCESS_ALLOWED_ACE *)ace)->SidStart))) {
938 matches++;
939 break;
940 }
941 }
942
943 // if there are no SID matches, then add this existing ACE to the new ACL
944 if (matches == 0) {
945 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
946 ((PACE_HEADER)ace)->AceSize)) {
947 if (PrintMiscellaneous && Verbose) {
948 warning("AddAce failure: lasterror = %d \n", GetLastError());
949 }
950 FREE_C_HEAP_ARRAY(char, newACL);
951 return false;
952 }
953 }
954 ace_index++;
955 }
956 }
957
958 // add the passed-in access control entries to the new ACL
959 for (int i = 0; i < ace_count; i++) {
960 if (!AddAccessAllowedAce(newACL, ACL_REVISION,
961 aces[i].mask, aces[i].pSid)) {
962 if (PrintMiscellaneous && Verbose) {
963 warning("AddAccessAllowedAce failure: lasterror = %d \n",
964 GetLastError());
965 }
966 FREE_C_HEAP_ARRAY(char, newACL);
967 return false;
968 }
969 }
970
971 // now copy the rest of the inherited ACEs from the old ACL
972 if (aclinfo.AceCount != 0) {
973 // picking up at ace_index, where we left off in the
974 // previous ace_index loop
975 while (ace_index < aclinfo.AceCount) {
976 LPVOID ace;
977 if (!GetAce(oldACL, ace_index, &ace)) {
978 if (PrintMiscellaneous && Verbose) {
979 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
980 }
981 FREE_C_HEAP_ARRAY(char, newACL);
982 return false;
983 }
984 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
985 ((PACE_HEADER)ace)->AceSize)) {
986 if (PrintMiscellaneous && Verbose) {
987 warning("AddAce failure: lasterror = %d \n", GetLastError());
988 }
989 FREE_C_HEAP_ARRAY(char, newACL);
990 return false;
991 }
992 ace_index++;
993 }
994 }
995
996 // add the new ACL to the security descriptor.
997 if (!SetSecurityDescriptorDacl(pSD, TRUE, newACL, FALSE)) {
998 if (PrintMiscellaneous && Verbose) {
999 warning("SetSecurityDescriptorDacl failure:"
1000 " lasterror = %d \n", GetLastError());
1001 }
1002 FREE_C_HEAP_ARRAY(char, newACL);
1003 return false;
1004 }
1005
1006 // if running on windows 2000 or later, set the automatic inheritance
1007 // control flags.
1008 SetSecurityDescriptorControlFnPtr _SetSecurityDescriptorControl;
1009 _SetSecurityDescriptorControl = (SetSecurityDescriptorControlFnPtr)
1010 GetProcAddress(GetModuleHandle(TEXT("advapi32.dll")),
1011 "SetSecurityDescriptorControl");
1012
1013 if (_SetSecurityDescriptorControl != NULL) {
1014 // We do not want to further propagate inherited DACLs, so making them
1015 // protected prevents that.
1016 if (!_SetSecurityDescriptorControl(pSD, SE_DACL_PROTECTED,
1017 SE_DACL_PROTECTED)) {
1018 if (PrintMiscellaneous && Verbose) {
1019 warning("SetSecurityDescriptorControl failure:"
1020 " lasterror = %d \n", GetLastError());
1021 }
1022 FREE_C_HEAP_ARRAY(char, newACL);
1023 return false;
1024 }
1025 }
1026 // Note, the security descriptor maintains a reference to the newACL, not
1027 // a copy of it. Therefore, the newACL is not freed here. It is freed when
1028 // the security descriptor containing its reference is freed.
1029 //
1030 return true;
1031 }
1032
1033 // method to create a security attributes structure, which contains a
1034 // security descriptor and an access control list comprised of 0 or more
1035 // access control entries. The method take an array of ace_data structures
1036 // that indicate the ACE to be added to the security descriptor.
1037 //
1038 // the caller must free the resources associated with the security
1039 // attributes structure created by this method by calling the
1040 // free_security_attr() method.
1041 //
1042 static LPSECURITY_ATTRIBUTES make_security_attr(ace_data_t aces[], int count) {
1043
1044 // allocate space for a security descriptor
1045 PSECURITY_DESCRIPTOR pSD = (PSECURITY_DESCRIPTOR)
1046 NEW_C_HEAP_ARRAY(char, SECURITY_DESCRIPTOR_MIN_LENGTH);
1047
1048 // initialize the security descriptor
1049 if (!InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION)) {
1050 if (PrintMiscellaneous && Verbose) {
1051 warning("InitializeSecurityDescriptor failure: "
1052 "lasterror = %d \n", GetLastError());
1053 }
1054 free_security_desc(pSD);
1055 return NULL;
1056 }
1057
1058 // add the access control entries
1059 if (!add_allow_aces(pSD, aces, count)) {
1060 free_security_desc(pSD);
1061 return NULL;
1062 }
1063
1064 // allocate and initialize the security attributes structure and
1065 // return it to the caller.
1066 //
1067 LPSECURITY_ATTRIBUTES lpSA = (LPSECURITY_ATTRIBUTES)
1068 NEW_C_HEAP_ARRAY(char, sizeof(SECURITY_ATTRIBUTES));
1069 lpSA->nLength = sizeof(SECURITY_ATTRIBUTES);
1070 lpSA->lpSecurityDescriptor = pSD;
1071 lpSA->bInheritHandle = FALSE;
1072
1073 return(lpSA);
1074 }
1075
1076 // method to create a security attributes structure with a restrictive
1077 // access control list that creates a set access rights for the user/owner
1078 // of the securable object and a separate set access rights for everyone else.
1079 // also provides for full access rights for the administrator group.
1080 //
1081 // the caller must free the resources associated with the security
1082 // attributes structure created by this method by calling the
1083 // free_security_attr() method.
1084 //
1085
1086 static LPSECURITY_ATTRIBUTES make_user_everybody_admin_security_attr(
1087 DWORD umask, DWORD emask, DWORD amask) {
1088
1089 ace_data_t aces[3];
1090
1091 // initialize the user ace data
1092 aces[0].pSid = get_user_sid(GetCurrentProcess());
1093 aces[0].mask = umask;
1094
1095 if (aces[0].pSid == 0)
1096 return NULL;
1097
1098 // get the well known SID for BUILTIN\Administrators
1099 PSID administratorsSid = NULL;
1100 SID_IDENTIFIER_AUTHORITY SIDAuthAdministrators = SECURITY_NT_AUTHORITY;
1101
1102 if (!AllocateAndInitializeSid( &SIDAuthAdministrators, 2,
1103 SECURITY_BUILTIN_DOMAIN_RID,
1104 DOMAIN_ALIAS_RID_ADMINS,
1105 0, 0, 0, 0, 0, 0, &administratorsSid)) {
1106
1107 if (PrintMiscellaneous && Verbose) {
1108 warning("AllocateAndInitializeSid failure: "
1109 "lasterror = %d \n", GetLastError());
1110 }
1111 return NULL;
1112 }
1113
1114 // initialize the ace data for administrator group
1115 aces[1].pSid = administratorsSid;
1116 aces[1].mask = amask;
1117
1118 // get the well known SID for the universal Everybody
1119 PSID everybodySid = NULL;
1120 SID_IDENTIFIER_AUTHORITY SIDAuthEverybody = SECURITY_WORLD_SID_AUTHORITY;
1121
1122 if (!AllocateAndInitializeSid( &SIDAuthEverybody, 1, SECURITY_WORLD_RID,
1123 0, 0, 0, 0, 0, 0, 0, &everybodySid)) {
1124
1125 if (PrintMiscellaneous && Verbose) {
1126 warning("AllocateAndInitializeSid failure: "
1127 "lasterror = %d \n", GetLastError());
1128 }
1129 return NULL;
1130 }
1131
1132 // initialize the ace data for everybody else.
1133 aces[2].pSid = everybodySid;
1134 aces[2].mask = emask;
1135
1136 // create a security attributes structure with access control
1137 // entries as initialized above.
1138 LPSECURITY_ATTRIBUTES lpSA = make_security_attr(aces, 3);
1139 FREE_C_HEAP_ARRAY(char, aces[0].pSid);
1140 FreeSid(everybodySid);
1141 FreeSid(administratorsSid);
1142 return(lpSA);
1143 }
1144
1145
1146 // method to create the security attributes structure for restricting
1147 // access to the user temporary directory.
1148 //
1149 // the caller must free the resources associated with the security
1150 // attributes structure created by this method by calling the
1151 // free_security_attr() method.
1152 //
1153 static LPSECURITY_ATTRIBUTES make_tmpdir_security_attr() {
1154
1155 // create full access rights for the user/owner of the directory
1156 // and read-only access rights for everybody else. This is
1157 // effectively equivalent to UNIX 755 permissions on a directory.
1158 //
1159 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_ALL_ACCESS;
1160 DWORD emask = GENERIC_READ | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1161 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1162
1163 return make_user_everybody_admin_security_attr(umask, emask, amask);
1164 }
1165
1166 // method to create the security attributes structure for restricting
1167 // access to the shared memory backing store file.
1168 //
1169 // the caller must free the resources associated with the security
1170 // attributes structure created by this method by calling the
1171 // free_security_attr() method.
1172 //
1173 static LPSECURITY_ATTRIBUTES make_file_security_attr() {
1174
1175 // create extensive access rights for the user/owner of the file
1176 // and attribute read-only access rights for everybody else. This
1177 // is effectively equivalent to UNIX 600 permissions on a file.
1178 //
1179 DWORD umask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1180 DWORD emask = STANDARD_RIGHTS_READ | FILE_READ_ATTRIBUTES |
1181 FILE_READ_EA | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1182 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1183
1184 return make_user_everybody_admin_security_attr(umask, emask, amask);
1185 }
1186
1187 // method to create the security attributes structure for restricting
1188 // access to the name shared memory file mapping object.
1189 //
1190 // the caller must free the resources associated with the security
1191 // attributes structure created by this method by calling the
1192 // free_security_attr() method.
1193 //
1194 static LPSECURITY_ATTRIBUTES make_smo_security_attr() {
1195
1196 // create extensive access rights for the user/owner of the shared
1197 // memory object and attribute read-only access rights for everybody
1198 // else. This is effectively equivalent to UNIX 600 permissions on
1199 // on the shared memory object.
1200 //
1201 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_MAP_ALL_ACCESS;
1202 DWORD emask = STANDARD_RIGHTS_READ; // attributes only
1203 DWORD amask = STANDARD_RIGHTS_ALL | FILE_MAP_ALL_ACCESS;
1204
1205 return make_user_everybody_admin_security_attr(umask, emask, amask);
1206 }
1207
1208 // make the user specific temporary directory
1209 //
1210 static bool make_user_tmp_dir(const char* dirname) {
1211
1212
1213 LPSECURITY_ATTRIBUTES pDirSA = make_tmpdir_security_attr();
1214 if (pDirSA == NULL) {
1215 return false;
1216 }
1217
1218
1219 // create the directory with the given security attributes
1220 if (!CreateDirectory(dirname, pDirSA)) {
1221 DWORD lasterror = GetLastError();
1222 if (lasterror == ERROR_ALREADY_EXISTS) {
1223 // The directory already exists and was probably created by another
1224 // JVM instance. However, this could also be the result of a
1225 // deliberate symlink. Verify that the existing directory is safe.
1226 //
1227 if (!is_directory_secure(dirname)) {
1228 // directory is not secure
1229 if (PrintMiscellaneous && Verbose) {
1230 warning("%s directory is insecure\n", dirname);
1231 }
1232 return false;
1233 }
1234 // The administrator should be able to delete this directory.
1235 // But the directory created by previous version of JVM may not
1236 // have permission for administrators to delete this directory.
1237 // So add full permission to the administrator. Also setting new
1238 // DACLs might fix the corrupted the DACLs.
1239 SECURITY_INFORMATION secInfo = DACL_SECURITY_INFORMATION;
1240 if (!SetFileSecurity(dirname, secInfo, pDirSA->lpSecurityDescriptor)) {
1241 if (PrintMiscellaneous && Verbose) {
1242 lasterror = GetLastError();
1243 warning("SetFileSecurity failed for %s directory. lasterror %d \n",
1244 dirname, lasterror);
1245 }
1246 }
1247 }
1248 else {
1249 if (PrintMiscellaneous && Verbose) {
1250 warning("CreateDirectory failed: %d\n", GetLastError());
1251 }
1252 return false;
1253 }
1254 }
1255
1256 // free the security attributes structure
1257 free_security_attr(pDirSA);
1258
1259 return true;
1260 }
1261
1262 // create the shared memory resources
1263 //
1264 // This function creates the shared memory resources. This includes
1265 // the backing store file and the file mapping shared memory object.
1266 //
1267 static HANDLE create_sharedmem_resources(const char* dirname, const char* filename, const char* objectname, size_t size) {
1268
1269 HANDLE fh = INVALID_HANDLE_VALUE;
1270 HANDLE fmh = NULL;
1271
1272
1273 // create the security attributes for the backing store file
1274 LPSECURITY_ATTRIBUTES lpFileSA = make_file_security_attr();
1275 if (lpFileSA == NULL) {
1276 return NULL;
1277 }
1278
1279 // create the security attributes for the shared memory object
1280 LPSECURITY_ATTRIBUTES lpSmoSA = make_smo_security_attr();
1281 if (lpSmoSA == NULL) {
1282 free_security_attr(lpFileSA);
1283 return NULL;
1284 }
1285
1286 // create the user temporary directory
1287 if (!make_user_tmp_dir(dirname)) {
1288 // could not make/find the directory or the found directory
1289 // was not secure
1290 return NULL;
1291 }
1292
1293 // Create the file - the FILE_FLAG_DELETE_ON_CLOSE flag allows the
1294 // file to be deleted by the last process that closes its handle to
1295 // the file. This is important as the apis do not allow a terminating
1296 // JVM being monitored by another process to remove the file name.
1297 //
1298 // the FILE_SHARE_DELETE share mode is valid only in winnt
1299 //
1300 fh = CreateFile(
1301 filename, /* LPCTSTR file name */
1302
1303 GENERIC_READ|GENERIC_WRITE, /* DWORD desired access */
1304
1305 (os::win32::is_nt() ? FILE_SHARE_DELETE : 0)|
1306 FILE_SHARE_READ, /* DWORD share mode, future READONLY
1307 * open operations allowed
1308 */
1309 lpFileSA, /* LPSECURITY security attributes */
1310 CREATE_ALWAYS, /* DWORD creation disposition
1311 * create file, if it already
1312 * exists, overwrite it.
1313 */
1314 FILE_FLAG_DELETE_ON_CLOSE, /* DWORD flags and attributes */
1315
1316 NULL); /* HANDLE template file access */
1317
1318 free_security_attr(lpFileSA);
1319
1320 if (fh == INVALID_HANDLE_VALUE) {
1321 DWORD lasterror = GetLastError();
1322 if (PrintMiscellaneous && Verbose) {
1323 warning("could not create file %s: %d\n", filename, lasterror);
1324 }
1325 return NULL;
1326 }
1327
1328 // try to create the file mapping
1329 fmh = create_file_mapping(objectname, fh, lpSmoSA, size);
1330
1331 free_security_attr(lpSmoSA);
1332
1333 if (fmh == NULL) {
1334 // closing the file handle here will decrement the reference count
1335 // on the file. When all processes accessing the file close their
1336 // handle to it, the reference count will decrement to 0 and the
1337 // OS will delete the file. These semantics are requested by the
1338 // FILE_FLAG_DELETE_ON_CLOSE flag in CreateFile call above.
1339 CloseHandle(fh);
1340 fh = NULL;
1341 return NULL;
1342 }
1343
1344 // the file has been successfully created and the file mapping
1345 // object has been created.
1346 sharedmem_fileHandle = fh;
1347 sharedmem_fileName = strdup(filename);
1348
1349 return fmh;
1350 }
1351
1352 // open the shared memory object for the given vmid.
1353 //
1354 static HANDLE open_sharedmem_object(const char* objectname, DWORD ofm_access, TRAPS) {
1355
1356 HANDLE fmh;
1357
1358 // open the file mapping with the requested mode
1359 fmh = OpenFileMapping(
1360 ofm_access, /* DWORD access mode */
1361 FALSE, /* BOOL inherit flag - Do not allow inherit */
1362 objectname); /* name for object */
1363
1364 if (fmh == NULL) {
1365 if (PrintMiscellaneous && Verbose) {
1366 warning("OpenFileMapping failed for shared memory object %s:"
1367 " lasterror = %d\n", objectname, GetLastError());
1368 }
1369 THROW_MSG_(vmSymbols::java_lang_Exception(),
1370 "Could not open PerfMemory", INVALID_HANDLE_VALUE);
1371 }
1372
1373 return fmh;;
1374 }
1375
1376 // create a named shared memory region
1377 //
1378 // On Win32, a named shared memory object has a name space that
1379 // is independent of the file system name space. Shared memory object,
1380 // or more precisely, file mapping objects, provide no mechanism to
1381 // inquire the size of the memory region. There is also no api to
1382 // enumerate the memory regions for various processes.
1383 //
1384 // This implementation utilizes the shared memory name space in parallel
1385 // with the file system name space. This allows us to determine the
1386 // size of the shared memory region from the size of the file and it
1387 // allows us to provide a common, file system based name space for
1388 // shared memory across platforms.
1389 //
1390 static char* mapping_create_shared(size_t size) {
1391
1392 void *mapAddress;
1393 int vmid = os::current_process_id();
1394
1395 // get the name of the user associated with this process
1396 char* user = get_user_name();
1397
1398 if (user == NULL) {
1399 return NULL;
1400 }
1401
1402 // construct the name of the user specific temporary directory
1403 char* dirname = get_user_tmp_dir(user);
1404
1405 // check that the file system is secure - i.e. it supports ACLs.
1406 if (!is_filesystem_secure(dirname)) {
1407 return NULL;
1408 }
1409
1410 // create the names of the backing store files and for the
1411 // share memory object.
1412 //
1413 char* filename = get_sharedmem_filename(dirname, vmid);
1414 char* objectname = get_sharedmem_objectname(user, vmid);
1415
1416 // cleanup any stale shared memory resources
1417 cleanup_sharedmem_resources(dirname);
1418
1419 assert(((size != 0) && (size % os::vm_page_size() == 0)),
1420 "unexpected PerfMemry region size");
1421
1422 FREE_C_HEAP_ARRAY(char, user);
1423
1424 // create the shared memory resources
1425 sharedmem_fileMapHandle =
1426 create_sharedmem_resources(dirname, filename, objectname, size);
1427
1428 FREE_C_HEAP_ARRAY(char, filename);
1429 FREE_C_HEAP_ARRAY(char, objectname);
1430 FREE_C_HEAP_ARRAY(char, dirname);
1431
1432 if (sharedmem_fileMapHandle == NULL) {
1433 return NULL;
1434 }
1435
1436 // map the file into the address space
1437 mapAddress = MapViewOfFile(
1438 sharedmem_fileMapHandle, /* HANDLE = file mapping object */
1439 FILE_MAP_ALL_ACCESS, /* DWORD access flags */
1440 0, /* DWORD High word of offset */
1441 0, /* DWORD Low word of offset */
1442 (DWORD)size); /* DWORD Number of bytes to map */
1443
1444 if (mapAddress == NULL) {
1445 if (PrintMiscellaneous && Verbose) {
1446 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1447 }
1448 CloseHandle(sharedmem_fileMapHandle);
1449 sharedmem_fileMapHandle = NULL;
1450 return NULL;
1451 }
1452
1453 // clear the shared memory region
1454 (void)memset(mapAddress, '\0', size);
1455
1456 return (char*) mapAddress;
1457 }
1458
1459 // this method deletes the file mapping object.
1460 //
1461 static void delete_file_mapping(char* addr, size_t size) {
1462
1463 // cleanup the persistent shared memory resources. since DestroyJavaVM does
1464 // not support unloading of the JVM, unmapping of the memory resource is not
1465 // performed. The memory will be reclaimed by the OS upon termination of all
1466 // processes mapping the resource. The file mapping handle and the file
1467 // handle are closed here to expedite the remove of the file by the OS. The
1468 // file is not removed directly because it was created with
1469 // FILE_FLAG_DELETE_ON_CLOSE semantics and any attempt to remove it would
1470 // be unsuccessful.
1471
1472 // close the fileMapHandle. the file mapping will still be retained
1473 // by the OS as long as any other JVM processes has an open file mapping
1474 // handle or a mapped view of the file.
1475 //
1476 if (sharedmem_fileMapHandle != NULL) {
1477 CloseHandle(sharedmem_fileMapHandle);
1478 sharedmem_fileMapHandle = NULL;
1479 }
1480
1481 // close the file handle. This will decrement the reference count on the
1482 // backing store file. When the reference count decrements to 0, the OS
1483 // will delete the file. These semantics apply because the file was
1484 // created with the FILE_FLAG_DELETE_ON_CLOSE flag.
1485 //
1486 if (sharedmem_fileHandle != INVALID_HANDLE_VALUE) {
1487 CloseHandle(sharedmem_fileHandle);
1488 sharedmem_fileHandle = INVALID_HANDLE_VALUE;
1489 }
1490 }
1491
1492 // this method determines the size of the shared memory file
1493 //
1494 static size_t sharedmem_filesize(const char* filename, TRAPS) {
1495
1496 struct stat statbuf;
1497
1498 // get the file size
1499 //
1500 // on win95/98/me, _stat returns a file size of 0 bytes, but on
1501 // winnt/2k the appropriate file size is returned. support for
1502 // the sharable aspects of performance counters was abandonded
1503 // on the non-nt win32 platforms due to this and other api
1504 // inconsistencies
1505 //
1506 if (::stat(filename, &statbuf) == OS_ERR) {
1507 if (PrintMiscellaneous && Verbose) {
1508 warning("stat %s failed: %s\n", filename, strerror(errno));
1509 }
1510 THROW_MSG_0(vmSymbols::java_io_IOException(),
1511 "Could not determine PerfMemory size");
1512 }
1513
1514 if ((statbuf.st_size == 0) || (statbuf.st_size % os::vm_page_size() != 0)) {
1515 if (PrintMiscellaneous && Verbose) {
1516 warning("unexpected file size: size = " SIZE_FORMAT "\n",
1517 statbuf.st_size);
1518 }
1519 THROW_MSG_0(vmSymbols::java_lang_Exception(),
1520 "Invalid PerfMemory size");
1521 }
1522
1523 return statbuf.st_size;
1524 }
1525
1526 // this method opens a file mapping object and maps the object
1527 // into the address space of the process
1528 //
1529 static void open_file_mapping(const char* user, int vmid,
1530 PerfMemory::PerfMemoryMode mode,
1531 char** addrp, size_t* sizep, TRAPS) {
1532
1533 ResourceMark rm;
1534
1535 void *mapAddress = 0;
1536 size_t size;
1537 HANDLE fmh;
1538 DWORD ofm_access;
1539 DWORD mv_access;
1540 const char* luser = NULL;
1541
1542 if (mode == PerfMemory::PERF_MODE_RO) {
1543 ofm_access = FILE_MAP_READ;
1544 mv_access = FILE_MAP_READ;
1545 }
1546 else if (mode == PerfMemory::PERF_MODE_RW) {
1547 #ifdef LATER
1548 ofm_access = FILE_MAP_READ | FILE_MAP_WRITE;
1549 mv_access = FILE_MAP_READ | FILE_MAP_WRITE;
1550 #else
1551 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1552 "Unsupported access mode");
1553 #endif
1554 }
1555 else {
1556 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1557 "Illegal access mode");
1558 }
1559
1560 // if a user name wasn't specified, then find the user name for
1561 // the owner of the target vm.
1562 if (user == NULL || strlen(user) == 0) {
1563 luser = get_user_name(vmid);
1564 }
1565 else {
1566 luser = user;
1567 }
1568
1569 if (luser == NULL) {
1570 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1571 "Could not map vmid to user name");
1572 }
1573
1574 // get the names for the resources for the target vm
1575 char* dirname = get_user_tmp_dir(luser);
1576
1577 // since we don't follow symbolic links when creating the backing
1578 // store file, we also don't following them when attaching
1579 //
1580 if (!is_directory_secure(dirname)) {
1581 FREE_C_HEAP_ARRAY(char, dirname);
1582 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1583 "Process not found");
1584 }
1585
1586 char* filename = get_sharedmem_filename(dirname, vmid);
1587 char* objectname = get_sharedmem_objectname(luser, vmid);
1588
1589 // copy heap memory to resource memory. the objectname and
1590 // filename are passed to methods that may throw exceptions.
1591 // using resource arrays for these names prevents the leaks
1592 // that would otherwise occur.
1593 //
1594 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
1595 char* robjectname = NEW_RESOURCE_ARRAY(char, strlen(objectname) + 1);
1596 strcpy(rfilename, filename);
1597 strcpy(robjectname, objectname);
1598
1599 // free the c heap resources that are no longer needed
1600 if (luser != user) FREE_C_HEAP_ARRAY(char, luser);
1601 FREE_C_HEAP_ARRAY(char, dirname);
1602 FREE_C_HEAP_ARRAY(char, filename);
1603 FREE_C_HEAP_ARRAY(char, objectname);
1604
1605 if (*sizep == 0) {
1606 size = sharedmem_filesize(rfilename, CHECK);
1607 assert(size != 0, "unexpected size");
1608 }
1609
1610 // Open the file mapping object with the given name
1611 fmh = open_sharedmem_object(robjectname, ofm_access, CHECK);
1612
1613 assert(fmh != INVALID_HANDLE_VALUE, "unexpected handle value");
1614
1615 // map the entire file into the address space
1616 mapAddress = MapViewOfFile(
1617 fmh, /* HANDLE Handle of file mapping object */
1618 mv_access, /* DWORD access flags */
1619 0, /* DWORD High word of offset */
1620 0, /* DWORD Low word of offset */
1621 size); /* DWORD Number of bytes to map */
1622
1623 if (mapAddress == NULL) {
1624 if (PrintMiscellaneous && Verbose) {
1625 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1626 }
1627 CloseHandle(fmh);
1628 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
1629 "Could not map PerfMemory");
1630 }
1631
1632 *addrp = (char*)mapAddress;
1633 *sizep = size;
1634
1635 // File mapping object can be closed at this time without
1636 // invalidating the mapped view of the file
1637 CloseHandle(fmh);
1638
1639 if (PerfTraceMemOps) {
1640 tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
1641 INTPTR_FORMAT "\n", size, vmid, mapAddress);
1642 }
1643 }
1644
1645 // this method unmaps the the mapped view of the the
1646 // file mapping object.
1647 //
1648 static void remove_file_mapping(char* addr) {
1649
1650 // the file mapping object was closed in open_file_mapping()
1651 // after the file map view was created. We only need to
1652 // unmap the file view here.
1653 UnmapViewOfFile(addr);
1654 }
1655
1656 // create the PerfData memory region in shared memory.
1657 static char* create_shared_memory(size_t size) {
1658
1659 return mapping_create_shared(size);
1660 }
1661
1662 // release a named, shared memory region
1663 //
1664 void delete_shared_memory(char* addr, size_t size) {
1665
1666 delete_file_mapping(addr, size);
1667 }
1668
1669
1670
1671
1672 // create the PerfData memory region
1673 //
1674 // This method creates the memory region used to store performance
1675 // data for the JVM. The memory may be created in standard or
1676 // shared memory.
1677 //
1678 void PerfMemory::create_memory_region(size_t size) {
1679
1680 if (PerfDisableSharedMem || !os::win32::is_nt()) {
1681 // do not share the memory for the performance data.
1682 PerfDisableSharedMem = true;
1683 _start = create_standard_memory(size);
1684 }
1685 else {
1686 _start = create_shared_memory(size);
1687 if (_start == NULL) {
1688
1689 // creation of the shared memory region failed, attempt
1690 // to create a contiguous, non-shared memory region instead.
1691 //
1692 if (PrintMiscellaneous && Verbose) {
1693 warning("Reverting to non-shared PerfMemory region.\n");
1694 }
1695 PerfDisableSharedMem = true;
1696 _start = create_standard_memory(size);
1697 }
1698 }
1699
1700 if (_start != NULL) _capacity = size;
1701
1702 }
1703
1704 // delete the PerfData memory region
1705 //
1706 // This method deletes the memory region used to store performance
1707 // data for the JVM. The memory region indicated by the <address, size>
1708 // tuple will be inaccessible after a call to this method.
1709 //
1710 void PerfMemory::delete_memory_region() {
1711
1712 assert((start() != NULL && capacity() > 0), "verify proper state");
1713
1714 // If user specifies PerfDataSaveFile, it will save the performance data
1715 // to the specified file name no matter whether PerfDataSaveToFile is specified
1716 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
1717 // -XX:+PerfDataSaveToFile.
1718 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
1719 save_memory_to_file(start(), capacity());
1720 }
1721
1722 if (PerfDisableSharedMem) {
1723 delete_standard_memory(start(), capacity());
1724 }
1725 else {
1726 delete_shared_memory(start(), capacity());
1727 }
1728 }
1729
1730 // attach to the PerfData memory region for another JVM
1731 //
1732 // This method returns an <address, size> tuple that points to
1733 // a memory buffer that is kept reasonably synchronized with
1734 // the PerfData memory region for the indicated JVM. This
1735 // buffer may be kept in synchronization via shared memory
1736 // or some other mechanism that keeps the buffer updated.
1737 //
1738 // If the JVM chooses not to support the attachability feature,
1739 // this method should throw an UnsupportedOperation exception.
1740 //
1741 // This implementation utilizes named shared memory to map
1742 // the indicated process's PerfData memory region into this JVMs
1743 // address space.
1744 //
1745 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode,
1746 char** addrp, size_t* sizep, TRAPS) {
1747
1748 if (vmid == 0 || vmid == os::current_process_id()) {
1749 *addrp = start();
1750 *sizep = capacity();
1751 return;
1752 }
1753
1754 open_file_mapping(user, vmid, mode, addrp, sizep, CHECK);
1755 }
1756
1757 // detach from the PerfData memory region of another JVM
1758 //
1759 // This method detaches the PerfData memory region of another
1760 // JVM, specified as an <address, size> tuple of a buffer
1761 // in this process's address space. This method may perform
1762 // arbitrary actions to accomplish the detachment. The memory
1763 // region specified by <address, size> will be inaccessible after
1764 // a call to this method.
1765 //
1766 // If the JVM chooses not to support the attachability feature,
1767 // this method should throw an UnsupportedOperation exception.
1768 //
1769 // This implementation utilizes named shared memory to detach
1770 // the indicated process's PerfData memory region from this
1771 // process's address space.
1772 //
1773 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
1774
1775 assert(addr != 0, "address sanity check");
1776 assert(bytes > 0, "capacity sanity check");
1777
1778 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
1779 // prevent accidental detachment of this process's PerfMemory region
1780 return;
1781 }
1782
1783 remove_file_mapping(addr);
1784 }
1785
1786 char* PerfMemory::backing_store_filename() {
1787 return sharedmem_fileName;
1788 }