1 /*
2 * Copyright (c) 2001, 2017, 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 "logging/log.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "os_windows.inline.hpp"
32 #include "runtime/handles.inline.hpp"
33 #include "runtime/os.hpp"
34 #include "runtime/perfMemory.hpp"
35 #include "services/memTracker.hpp"
36 #include "utilities/exceptions.hpp"
37
38 #include <windows.h>
39 #include <sys/types.h>
40 #include <sys/stat.h>
41 #include <errno.h>
42 #include <lmcons.h>
43
44 typedef BOOL (WINAPI *SetSecurityDescriptorControlFnPtr)(
45 IN PSECURITY_DESCRIPTOR pSecurityDescriptor,
46 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsOfInterest,
47 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsToSet);
48
49 // Standard Memory Implementation Details
50
51 // create the PerfData memory region in standard memory.
52 //
53 static char* create_standard_memory(size_t size) {
54
55 // allocate an aligned chuck of memory
56 char* mapAddress = os::reserve_memory(size);
57
58 if (mapAddress == NULL) {
59 return NULL;
60 }
61
62 // commit memory
63 if (!os::commit_memory(mapAddress, size, !ExecMem)) {
64 if (PrintMiscellaneous && Verbose) {
65 warning("Could not commit PerfData memory\n");
66 }
67 os::release_memory(mapAddress, size);
68 return NULL;
69 }
70
71 return mapAddress;
72 }
73
74 // delete the PerfData memory region
75 //
76 static void delete_standard_memory(char* addr, size_t size) {
77
78 // there are no persistent external resources to cleanup for standard
79 // memory. since DestroyJavaVM does not support unloading of the JVM,
80 // cleanup of the memory resource is not performed. The memory will be
81 // reclaimed by the OS upon termination of the process.
82 //
83 return;
84
85 }
86
87 // save the specified memory region to the given file
88 //
89 static void save_memory_to_file(char* addr, size_t size) {
90
91 const char* destfile = PerfMemory::get_perfdata_file_path();
92 assert(destfile[0] != '\0', "invalid Perfdata file path");
93
94 int fd = ::_open(destfile, _O_BINARY|_O_CREAT|_O_WRONLY|_O_TRUNC,
95 _S_IREAD|_S_IWRITE);
96
97 if (fd == OS_ERR) {
98 if (PrintMiscellaneous && Verbose) {
99 warning("Could not create Perfdata save file: %s: %s\n",
100 destfile, os::strerror(errno));
101 }
102 } else {
103 for (size_t remaining = size; remaining > 0;) {
104
105 int nbytes = ::_write(fd, addr, (unsigned int)remaining);
106 if (nbytes == OS_ERR) {
107 if (PrintMiscellaneous && Verbose) {
108 warning("Could not write Perfdata save file: %s: %s\n",
109 destfile, os::strerror(errno));
110 }
111 break;
112 }
113
114 remaining -= (size_t)nbytes;
115 addr += nbytes;
116 }
117
118 int result = ::_close(fd);
119 if (PrintMiscellaneous && Verbose) {
120 if (result == OS_ERR) {
121 warning("Could not close %s: %s\n", destfile, os::strerror(errno));
122 }
123 }
124 }
125
126 FREE_C_HEAP_ARRAY(char, destfile);
127 }
128
129 // Shared Memory Implementation Details
130
131 // Note: the win32 shared memory implementation uses two objects to represent
132 // the shared memory: a windows kernel based file mapping object and a backing
133 // store file. On windows, the name space for shared memory is a kernel
134 // based name space that is disjoint from other win32 name spaces. Since Java
135 // is unaware of this name space, a parallel file system based name space is
136 // maintained, which provides a common file system based shared memory name
137 // space across the supported platforms and one that Java apps can deal with
138 // through simple file apis.
139 //
140 // For performance and resource cleanup reasons, it is recommended that the
141 // user specific directory and the backing store file be stored in either a
142 // RAM based file system or a local disk based file system. Network based
143 // file systems are not recommended for performance reasons. In addition,
144 // use of SMB network based file systems may result in unsuccesful cleanup
145 // of the disk based resource on exit of the VM. The Windows TMP and TEMP
146 // environement variables, as used by the GetTempPath() Win32 API (see
147 // os::get_temp_directory() in os_win32.cpp), control the location of the
148 // user specific directory and the shared memory backing store file.
149
150 static HANDLE sharedmem_fileMapHandle = NULL;
151 static HANDLE sharedmem_fileHandle = INVALID_HANDLE_VALUE;
152 static char* sharedmem_fileName = NULL;
153
154 // return the user specific temporary directory name.
155 //
156 // the caller is expected to free the allocated memory.
157 //
158 static char* get_user_tmp_dir(const char* user) {
159
160 const char* tmpdir = os::get_temp_directory();
161 const char* perfdir = PERFDATA_NAME;
162 size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
163 char* dirname = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
164
165 // construct the path name to user specific tmp directory
166 _snprintf(dirname, nbytes, "%s\\%s_%s", tmpdir, perfdir, user);
167
168 return dirname;
169 }
170
171 // convert the given file name into a process id. if the file
172 // does not meet the file naming constraints, return 0.
173 //
174 static int filename_to_pid(const char* filename) {
175
176 // a filename that doesn't begin with a digit is not a
177 // candidate for conversion.
178 //
179 if (!isdigit(*filename)) {
180 return 0;
181 }
182
183 // check if file name can be converted to an integer without
184 // any leftover characters.
185 //
186 char* remainder = NULL;
187 errno = 0;
188 int pid = (int)strtol(filename, &remainder, 10);
189
190 if (errno != 0) {
191 return 0;
192 }
193
194 // check for left over characters. If any, then the filename is
195 // not a candidate for conversion.
196 //
197 if (remainder != NULL && *remainder != '\0') {
198 return 0;
199 }
200
201 // successful conversion, return the pid
202 return pid;
203 }
204
205 // check if the given path is considered a secure directory for
206 // the backing store files. Returns true if the directory exists
207 // and is considered a secure location. Returns false if the path
208 // is a symbolic link or if an error occurred.
209 //
210 static bool is_directory_secure(const char* path) {
211
212 DWORD fa;
213
214 fa = GetFileAttributes(path);
215 if (fa == 0xFFFFFFFF) {
216 DWORD lasterror = GetLastError();
217 if (lasterror == ERROR_FILE_NOT_FOUND) {
218 return false;
219 }
220 else {
221 // unexpected error, declare the path insecure
222 if (PrintMiscellaneous && Verbose) {
223 warning("could not get attributes for file %s: ",
224 " lasterror = %d\n", path, lasterror);
225 }
226 return false;
227 }
228 }
229
230 if (fa & FILE_ATTRIBUTE_REPARSE_POINT) {
231 // we don't accept any redirection for the user specific directory
232 // so declare the path insecure. This may be too conservative,
233 // as some types of reparse points might be acceptable, but it
234 // is probably more secure to avoid these conditions.
235 //
236 if (PrintMiscellaneous && Verbose) {
237 warning("%s is a reparse point\n", path);
238 }
239 return false;
240 }
241
242 if (fa & FILE_ATTRIBUTE_DIRECTORY) {
243 // this is the expected case. Since windows supports symbolic
244 // links to directories only, not to files, there is no need
245 // to check for open write permissions on the directory. If the
246 // directory has open write permissions, any files deposited that
247 // are not expected will be removed by the cleanup code.
248 //
249 return true;
250 }
251 else {
252 // this is either a regular file or some other type of file,
253 // any of which are unexpected and therefore insecure.
254 //
255 if (PrintMiscellaneous && Verbose) {
256 warning("%s is not a directory, file attributes = "
257 INTPTR_FORMAT "\n", path, fa);
258 }
259 return false;
260 }
261 }
262
263 // return the user name for the owner of this process
264 //
265 // the caller is expected to free the allocated memory.
266 //
267 static char* get_user_name() {
268
269 /* get the user name. This code is adapted from code found in
270 * the jdk in src/windows/native/java/lang/java_props_md.c
271 * java_props_md.c 1.29 02/02/06. According to the original
272 * source, the call to GetUserName is avoided because of a resulting
273 * increase in footprint of 100K.
274 */
275 char* user = getenv("USERNAME");
276 char buf[UNLEN+1];
277 DWORD buflen = sizeof(buf);
278 if (user == NULL || strlen(user) == 0) {
279 if (GetUserName(buf, &buflen)) {
280 user = buf;
281 }
282 else {
283 return NULL;
284 }
285 }
286
287 char* user_name = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
288 strcpy(user_name, user);
289
290 return user_name;
291 }
292
293 // return the name of the user that owns the process identified by vmid.
294 //
295 // This method uses a slow directory search algorithm to find the backing
296 // store file for the specified vmid and returns the user name, as determined
297 // by the user name suffix of the hsperfdata_<username> directory name.
298 //
299 // the caller is expected to free the allocated memory.
300 //
301 static char* get_user_name_slow(int vmid) {
302
303 // directory search
304 char* latest_user = NULL;
305 time_t latest_ctime = 0;
306
307 const char* tmpdirname = os::get_temp_directory();
308
309 DIR* tmpdirp = os::opendir(tmpdirname);
310
311 if (tmpdirp == NULL) {
312 return NULL;
313 }
314
315 // for each entry in the directory that matches the pattern hsperfdata_*,
316 // open the directory and check if the file for the given vmid exists.
317 // The file with the expected name and the latest creation date is used
318 // to determine the user name for the process id.
319 //
320 struct dirent* dentry;
321 char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname), mtInternal);
322 errno = 0;
323 while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
324
325 // check if the directory entry is a hsperfdata file
326 if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
327 continue;
328 }
329
330 char* usrdir_name = NEW_C_HEAP_ARRAY(char,
331 strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal);
332 strcpy(usrdir_name, tmpdirname);
333 strcat(usrdir_name, "\\");
334 strcat(usrdir_name, dentry->d_name);
335
336 DIR* subdirp = os::opendir(usrdir_name);
337
338 if (subdirp == NULL) {
339 FREE_C_HEAP_ARRAY(char, usrdir_name);
340 continue;
341 }
342
343 // Since we don't create the backing store files in directories
344 // pointed to by symbolic links, we also don't follow them when
345 // looking for the files. We check for a symbolic link after the
346 // call to opendir in order to eliminate a small window where the
347 // symlink can be exploited.
348 //
349 if (!is_directory_secure(usrdir_name)) {
350 FREE_C_HEAP_ARRAY(char, usrdir_name);
351 os::closedir(subdirp);
352 continue;
353 }
354
355 struct dirent* udentry;
356 char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name), mtInternal);
357 errno = 0;
358 while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
359
360 if (filename_to_pid(udentry->d_name) == vmid) {
361 struct stat statbuf;
362
363 char* filename = NEW_C_HEAP_ARRAY(char,
364 strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal);
365
366 strcpy(filename, usrdir_name);
367 strcat(filename, "\\");
368 strcat(filename, udentry->d_name);
369
370 if (::stat(filename, &statbuf) == OS_ERR) {
371 FREE_C_HEAP_ARRAY(char, filename);
372 continue;
373 }
374
375 // skip over files that are not regular files.
376 if ((statbuf.st_mode & S_IFMT) != S_IFREG) {
377 FREE_C_HEAP_ARRAY(char, filename);
378 continue;
379 }
380
381 // If we found a matching file with a newer creation time, then
382 // save the user name. The newer creation time indicates that
383 // we found a newer incarnation of the process associated with
384 // vmid. Due to the way that Windows recycles pids and the fact
385 // that we can't delete the file from the file system namespace
386 // until last close, it is possible for there to be more than
387 // one hsperfdata file with a name matching vmid (diff users).
388 //
389 // We no longer ignore hsperfdata files where (st_size == 0).
390 // In this function, all we're trying to do is determine the
391 // name of the user that owns the process associated with vmid
392 // so the size doesn't matter. Very rarely, we have observed
393 // hsperfdata files where (st_size == 0) and the st_size field
394 // later becomes the expected value.
395 //
396 if (statbuf.st_ctime > latest_ctime) {
397 char* user = strchr(dentry->d_name, '_') + 1;
398
399 if (latest_user != NULL) FREE_C_HEAP_ARRAY(char, latest_user);
400 latest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
401
402 strcpy(latest_user, user);
403 latest_ctime = statbuf.st_ctime;
404 }
405
406 FREE_C_HEAP_ARRAY(char, filename);
407 }
408 }
409 os::closedir(subdirp);
410 FREE_C_HEAP_ARRAY(char, udbuf);
411 FREE_C_HEAP_ARRAY(char, usrdir_name);
412 }
413 os::closedir(tmpdirp);
414 FREE_C_HEAP_ARRAY(char, tdbuf);
415
416 return(latest_user);
417 }
418
419 // return the name of the user that owns the process identified by vmid.
420 //
421 // note: this method should only be used via the Perf native methods.
422 // There are various costs to this method and limiting its use to the
423 // Perf native methods limits the impact to monitoring applications only.
424 //
425 static char* get_user_name(int vmid) {
426
427 // A fast implementation is not provided at this time. It's possible
428 // to provide a fast process id to user name mapping function using
429 // the win32 apis, but the default ACL for the process object only
430 // allows processes with the same owner SID to acquire the process
431 // handle (via OpenProcess(PROCESS_QUERY_INFORMATION)). It's possible
432 // to have the JVM change the ACL for the process object to allow arbitrary
433 // users to access the process handle and the process security token.
434 // The security ramifications need to be studied before providing this
435 // mechanism.
436 //
437 return get_user_name_slow(vmid);
438 }
439
440 // return the name of the shared memory file mapping object for the
441 // named shared memory region for the given user name and vmid.
442 //
443 // The file mapping object's name is not the file name. It is a name
444 // in a separate name space.
445 //
446 // the caller is expected to free the allocated memory.
447 //
448 static char *get_sharedmem_objectname(const char* user, int vmid) {
449
450 // construct file mapping object's name, add 3 for two '_' and a
451 // null terminator.
452 int nbytes = (int)strlen(PERFDATA_NAME) + (int)strlen(user) + 3;
453
454 // the id is converted to an unsigned value here because win32 allows
455 // negative process ids. However, OpenFileMapping API complains
456 // about a name containing a '-' characters.
457 //
458 nbytes += UINT_CHARS;
459 char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
460 _snprintf(name, nbytes, "%s_%s_%u", PERFDATA_NAME, user, vmid);
461
462 return name;
463 }
464
465 // return the file name of the backing store file for the named
466 // shared memory region for the given user name and vmid.
467 //
468 // the caller is expected to free the allocated memory.
469 //
470 static char* get_sharedmem_filename(const char* dirname, int vmid) {
471
472 // add 2 for the file separator and a null terminator.
473 size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
474
475 char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
476 _snprintf(name, nbytes, "%s\\%d", dirname, vmid);
477
478 return name;
479 }
480
481 // remove file
482 //
483 // this method removes the file with the given file name.
484 //
485 // Note: if the indicated file is on an SMB network file system, this
486 // method may be unsuccessful in removing the file.
487 //
488 static void remove_file(const char* dirname, const char* filename) {
489
490 size_t nbytes = strlen(dirname) + strlen(filename) + 2;
491 char* path = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
492
493 strcpy(path, dirname);
494 strcat(path, "\\");
495 strcat(path, filename);
496
497 if (::unlink(path) == OS_ERR) {
498 if (PrintMiscellaneous && Verbose) {
499 if (errno != ENOENT) {
500 warning("Could not unlink shared memory backing"
501 " store file %s : %s\n", path, os::strerror(errno));
502 }
503 }
504 }
505
506 FREE_C_HEAP_ARRAY(char, path);
507 }
508
509 // returns true if the process represented by pid is alive, otherwise
510 // returns false. the validity of the result is only accurate if the
511 // target process is owned by the same principal that owns this process.
512 // this method should not be used if to test the status of an otherwise
513 // arbitrary process unless it is know that this process has the appropriate
514 // privileges to guarantee a result valid.
515 //
516 static bool is_alive(int pid) {
517
518 HANDLE ph = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);
519 if (ph == NULL) {
520 // the process does not exist.
521 if (PrintMiscellaneous && Verbose) {
522 DWORD lastError = GetLastError();
523 if (lastError != ERROR_INVALID_PARAMETER) {
524 warning("OpenProcess failed: %d\n", GetLastError());
525 }
526 }
527 return false;
528 }
529
530 DWORD exit_status;
531 if (!GetExitCodeProcess(ph, &exit_status)) {
532 if (PrintMiscellaneous && Verbose) {
533 warning("GetExitCodeProcess failed: %d\n", GetLastError());
534 }
535 CloseHandle(ph);
536 return false;
537 }
538
539 CloseHandle(ph);
540 return (exit_status == STILL_ACTIVE) ? true : false;
541 }
542
543 // check if the file system is considered secure for the backing store files
544 //
545 static bool is_filesystem_secure(const char* path) {
546
547 char root_path[MAX_PATH];
548 char fs_type[MAX_PATH];
549
550 if (PerfBypassFileSystemCheck) {
551 if (PrintMiscellaneous && Verbose) {
552 warning("bypassing file system criteria checks for %s\n", path);
553 }
554 return true;
555 }
556
557 char* first_colon = strchr((char *)path, ':');
558 if (first_colon == NULL) {
559 if (PrintMiscellaneous && Verbose) {
560 warning("expected device specifier in path: %s\n", path);
561 }
562 return false;
563 }
564
565 size_t len = (size_t)(first_colon - path);
566 assert(len + 2 <= MAX_PATH, "unexpected device specifier length");
567 strncpy(root_path, path, len + 1);
568 root_path[len + 1] = '\\';
569 root_path[len + 2] = '\0';
570
571 // check that we have something like "C:\" or "AA:\"
572 assert(strlen(root_path) >= 3, "device specifier too short");
573 assert(strchr(root_path, ':') != NULL, "bad device specifier format");
574 assert(strchr(root_path, '\\') != NULL, "bad device specifier format");
575
576 DWORD maxpath;
577 DWORD flags;
578
579 if (!GetVolumeInformation(root_path, NULL, 0, NULL, &maxpath,
580 &flags, fs_type, MAX_PATH)) {
581 // we can't get information about the volume, so assume unsafe.
582 if (PrintMiscellaneous && Verbose) {
583 warning("could not get device information for %s: "
584 " path = %s: lasterror = %d\n",
585 root_path, path, GetLastError());
586 }
587 return false;
588 }
589
590 if ((flags & FS_PERSISTENT_ACLS) == 0) {
591 // file system doesn't support ACLs, declare file system unsafe
592 if (PrintMiscellaneous && Verbose) {
593 warning("file system type %s on device %s does not support"
594 " ACLs\n", fs_type, root_path);
595 }
596 return false;
597 }
598
599 if ((flags & FS_VOL_IS_COMPRESSED) != 0) {
600 // file system is compressed, declare file system unsafe
601 if (PrintMiscellaneous && Verbose) {
602 warning("file system type %s on device %s is compressed\n",
603 fs_type, root_path);
604 }
605 return false;
606 }
607
608 return true;
609 }
610
611 // cleanup stale shared memory resources
612 //
613 // This method attempts to remove all stale shared memory files in
614 // the named user temporary directory. It scans the named directory
615 // for files matching the pattern ^$[0-9]*$. For each file found, the
616 // process id is extracted from the file name and a test is run to
617 // determine if the process is alive. If the process is not alive,
618 // any stale file resources are removed.
619 //
620 static void cleanup_sharedmem_resources(const char* dirname) {
621
622 // open the user temp directory
623 DIR* dirp = os::opendir(dirname);
624
625 if (dirp == NULL) {
626 // directory doesn't exist, so there is nothing to cleanup
627 return;
628 }
629
630 if (!is_directory_secure(dirname)) {
631 // the directory is not secure, don't attempt any cleanup
632 os::closedir(dirp);
633 return;
634 }
635
636 // for each entry in the directory that matches the expected file
637 // name pattern, determine if the file resources are stale and if
638 // so, remove the file resources. Note, instrumented HotSpot processes
639 // for this user may start and/or terminate during this search and
640 // remove or create new files in this directory. The behavior of this
641 // loop under these conditions is dependent upon the implementation of
642 // opendir/readdir.
643 //
644 struct dirent* entry;
645 char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname), mtInternal);
646 errno = 0;
647 while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
648
649 int pid = filename_to_pid(entry->d_name);
650
651 if (pid == 0) {
652
653 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
654
655 // attempt to remove all unexpected files, except "." and ".."
656 remove_file(dirname, entry->d_name);
657 }
658
659 errno = 0;
660 continue;
661 }
662
663 // we now have a file name that converts to a valid integer
664 // that could represent a process id . if this process id
665 // matches the current process id or the process is not running,
666 // then remove the stale file resources.
667 //
668 // process liveness is detected by checking the exit status
669 // of the process. if the process id is valid and the exit status
670 // indicates that it is still running, the file file resources
671 // are not removed. If the process id is invalid, or if we don't
672 // have permissions to check the process status, or if the process
673 // id is valid and the process has terminated, the the file resources
674 // are assumed to be stale and are removed.
675 //
676 if (pid == os::current_process_id() || !is_alive(pid)) {
677
678 // we can only remove the file resources. Any mapped views
679 // of the file can only be unmapped by the processes that
680 // opened those views and the file mapping object will not
681 // get removed until all views are unmapped.
682 //
683 remove_file(dirname, entry->d_name);
684 }
685 errno = 0;
686 }
687 os::closedir(dirp);
688 FREE_C_HEAP_ARRAY(char, dbuf);
689 }
690
691 // create a file mapping object with the requested name, and size
692 // from the file represented by the given Handle object
693 //
694 static HANDLE create_file_mapping(const char* name, HANDLE fh, LPSECURITY_ATTRIBUTES fsa, size_t size) {
695
696 DWORD lowSize = (DWORD)size;
697 DWORD highSize = 0;
698 HANDLE fmh = NULL;
699
700 // Create a file mapping object with the given name. This function
701 // will grow the file to the specified size.
702 //
703 fmh = CreateFileMapping(
704 fh, /* HANDLE file handle for backing store */
705 fsa, /* LPSECURITY_ATTRIBUTES Not inheritable */
706 PAGE_READWRITE, /* DWORD protections */
707 highSize, /* DWORD High word of max size */
708 lowSize, /* DWORD Low word of max size */
709 name); /* LPCTSTR name for object */
710
711 if (fmh == NULL) {
712 if (PrintMiscellaneous && Verbose) {
713 warning("CreateFileMapping failed, lasterror = %d\n", GetLastError());
714 }
715 return NULL;
716 }
717
718 if (GetLastError() == ERROR_ALREADY_EXISTS) {
719
720 // a stale file mapping object was encountered. This object may be
721 // owned by this or some other user and cannot be removed until
722 // the other processes either exit or close their mapping objects
723 // and/or mapped views of this mapping object.
724 //
725 if (PrintMiscellaneous && Verbose) {
726 warning("file mapping already exists, lasterror = %d\n", GetLastError());
727 }
728
729 CloseHandle(fmh);
730 return NULL;
731 }
732
733 return fmh;
734 }
735
736
737 // method to free the given security descriptor and the contained
738 // access control list.
739 //
740 static void free_security_desc(PSECURITY_DESCRIPTOR pSD) {
741
742 BOOL success, exists, isdefault;
743 PACL pACL;
744
745 if (pSD != NULL) {
746
747 // get the access control list from the security descriptor
748 success = GetSecurityDescriptorDacl(pSD, &exists, &pACL, &isdefault);
749
750 // if an ACL existed and it was not a default acl, then it must
751 // be an ACL we enlisted. free the resources.
752 //
753 if (success && exists && pACL != NULL && !isdefault) {
754 FREE_C_HEAP_ARRAY(char, pACL);
755 }
756
757 // free the security descriptor
758 FREE_C_HEAP_ARRAY(char, pSD);
759 }
760 }
761
762 // method to free up a security attributes structure and any
763 // contained security descriptors and ACL
764 //
765 static void free_security_attr(LPSECURITY_ATTRIBUTES lpSA) {
766
767 if (lpSA != NULL) {
768 // free the contained security descriptor and the ACL
769 free_security_desc(lpSA->lpSecurityDescriptor);
770 lpSA->lpSecurityDescriptor = NULL;
771
772 // free the security attributes structure
773 FREE_C_HEAP_ARRAY(char, lpSA);
774 }
775 }
776
777 // get the user SID for the process indicated by the process handle
778 //
779 static PSID get_user_sid(HANDLE hProcess) {
780
781 HANDLE hAccessToken;
782 PTOKEN_USER token_buf = NULL;
783 DWORD rsize = 0;
784
785 if (hProcess == NULL) {
786 return NULL;
787 }
788
789 // get the process token
790 if (!OpenProcessToken(hProcess, TOKEN_READ, &hAccessToken)) {
791 if (PrintMiscellaneous && Verbose) {
792 warning("OpenProcessToken failure: lasterror = %d \n", GetLastError());
793 }
794 return NULL;
795 }
796
797 // determine the size of the token structured needed to retrieve
798 // the user token information from the access token.
799 //
800 if (!GetTokenInformation(hAccessToken, TokenUser, NULL, rsize, &rsize)) {
801 DWORD lasterror = GetLastError();
802 if (lasterror != ERROR_INSUFFICIENT_BUFFER) {
803 if (PrintMiscellaneous && Verbose) {
804 warning("GetTokenInformation failure: lasterror = %d,"
805 " rsize = %d\n", lasterror, rsize);
806 }
807 CloseHandle(hAccessToken);
808 return NULL;
809 }
810 }
811
812 token_buf = (PTOKEN_USER) NEW_C_HEAP_ARRAY(char, rsize, mtInternal);
813
814 // get the user token information
815 if (!GetTokenInformation(hAccessToken, TokenUser, token_buf, rsize, &rsize)) {
816 if (PrintMiscellaneous && Verbose) {
817 warning("GetTokenInformation failure: lasterror = %d,"
818 " rsize = %d\n", GetLastError(), rsize);
819 }
820 FREE_C_HEAP_ARRAY(char, token_buf);
821 CloseHandle(hAccessToken);
822 return NULL;
823 }
824
825 DWORD nbytes = GetLengthSid(token_buf->User.Sid);
826 PSID pSID = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
827
828 if (!CopySid(nbytes, pSID, token_buf->User.Sid)) {
829 if (PrintMiscellaneous && Verbose) {
830 warning("GetTokenInformation failure: lasterror = %d,"
831 " rsize = %d\n", GetLastError(), rsize);
832 }
833 FREE_C_HEAP_ARRAY(char, token_buf);
834 FREE_C_HEAP_ARRAY(char, pSID);
835 CloseHandle(hAccessToken);
836 return NULL;
837 }
838
839 // close the access token.
840 CloseHandle(hAccessToken);
841 FREE_C_HEAP_ARRAY(char, token_buf);
842
843 return pSID;
844 }
845
846 // structure used to consolidate access control entry information
847 //
848 typedef struct ace_data {
849 PSID pSid; // SID of the ACE
850 DWORD mask; // mask for the ACE
851 } ace_data_t;
852
853
854 // method to add an allow access control entry with the access rights
855 // indicated in mask for the principal indicated in SID to the given
856 // security descriptor. Much of the DACL handling was adapted from
857 // the example provided here:
858 // http://support.microsoft.com/kb/102102/EN-US/
859 //
860
861 static bool add_allow_aces(PSECURITY_DESCRIPTOR pSD,
862 ace_data_t aces[], int ace_count) {
863 PACL newACL = NULL;
864 PACL oldACL = NULL;
865
866 if (pSD == NULL) {
867 return false;
868 }
869
870 BOOL exists, isdefault;
871
872 // retrieve any existing access control list.
873 if (!GetSecurityDescriptorDacl(pSD, &exists, &oldACL, &isdefault)) {
874 if (PrintMiscellaneous && Verbose) {
875 warning("GetSecurityDescriptor failure: lasterror = %d \n",
876 GetLastError());
877 }
878 return false;
879 }
880
881 // get the size of the DACL
882 ACL_SIZE_INFORMATION aclinfo;
883
884 // GetSecurityDescriptorDacl may return true value for exists (lpbDaclPresent)
885 // while oldACL is NULL for some case.
886 if (oldACL == NULL) {
887 exists = FALSE;
888 }
889
890 if (exists) {
891 if (!GetAclInformation(oldACL, &aclinfo,
892 sizeof(ACL_SIZE_INFORMATION),
893 AclSizeInformation)) {
894 if (PrintMiscellaneous && Verbose) {
895 warning("GetAclInformation failure: lasterror = %d \n", GetLastError());
896 return false;
897 }
898 }
899 } else {
900 aclinfo.AceCount = 0; // assume NULL DACL
901 aclinfo.AclBytesFree = 0;
902 aclinfo.AclBytesInUse = sizeof(ACL);
903 }
904
905 // compute the size needed for the new ACL
906 // initial size of ACL is sum of the following:
907 // * size of ACL structure.
908 // * size of each ACE structure that ACL is to contain minus the sid
909 // sidStart member (DWORD) of the ACE.
910 // * length of the SID that each ACE is to contain.
911 DWORD newACLsize = aclinfo.AclBytesInUse +
912 (sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD)) * ace_count;
913 for (int i = 0; i < ace_count; i++) {
914 assert(aces[i].pSid != 0, "pSid should not be 0");
915 newACLsize += GetLengthSid(aces[i].pSid);
916 }
917
918 // create the new ACL
919 newACL = (PACL) NEW_C_HEAP_ARRAY(char, newACLsize, mtInternal);
920
921 if (!InitializeAcl(newACL, newACLsize, ACL_REVISION)) {
922 if (PrintMiscellaneous && Verbose) {
923 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
924 }
925 FREE_C_HEAP_ARRAY(char, newACL);
926 return false;
927 }
928
929 unsigned int ace_index = 0;
930 // copy any existing ACEs from the old ACL (if any) to the new ACL.
931 if (aclinfo.AceCount != 0) {
932 while (ace_index < aclinfo.AceCount) {
933 LPVOID ace;
934 if (!GetAce(oldACL, ace_index, &ace)) {
935 if (PrintMiscellaneous && Verbose) {
936 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
937 }
938 FREE_C_HEAP_ARRAY(char, newACL);
939 return false;
940 }
941 if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceFlags && INHERITED_ACE) {
942 // this is an inherited, allowed ACE; break from loop so we can
943 // add the new access allowed, non-inherited ACE in the correct
944 // position, immediately following all non-inherited ACEs.
945 break;
946 }
947
948 // determine if the SID of this ACE matches any of the SIDs
949 // for which we plan to set ACEs.
950 int matches = 0;
951 for (int i = 0; i < ace_count; i++) {
952 if (EqualSid(aces[i].pSid, &(((ACCESS_ALLOWED_ACE *)ace)->SidStart))) {
953 matches++;
954 break;
955 }
956 }
957
958 // if there are no SID matches, then add this existing ACE to the new ACL
959 if (matches == 0) {
960 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
961 ((PACE_HEADER)ace)->AceSize)) {
962 if (PrintMiscellaneous && Verbose) {
963 warning("AddAce failure: lasterror = %d \n", GetLastError());
964 }
965 FREE_C_HEAP_ARRAY(char, newACL);
966 return false;
967 }
968 }
969 ace_index++;
970 }
971 }
972
973 // add the passed-in access control entries to the new ACL
974 for (int i = 0; i < ace_count; i++) {
975 if (!AddAccessAllowedAce(newACL, ACL_REVISION,
976 aces[i].mask, aces[i].pSid)) {
977 if (PrintMiscellaneous && Verbose) {
978 warning("AddAccessAllowedAce failure: lasterror = %d \n",
979 GetLastError());
980 }
981 FREE_C_HEAP_ARRAY(char, newACL);
982 return false;
983 }
984 }
985
986 // now copy the rest of the inherited ACEs from the old ACL
987 if (aclinfo.AceCount != 0) {
988 // picking up at ace_index, where we left off in the
989 // previous ace_index loop
990 while (ace_index < aclinfo.AceCount) {
991 LPVOID ace;
992 if (!GetAce(oldACL, ace_index, &ace)) {
993 if (PrintMiscellaneous && Verbose) {
994 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
995 }
996 FREE_C_HEAP_ARRAY(char, newACL);
997 return false;
998 }
999 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
1000 ((PACE_HEADER)ace)->AceSize)) {
1001 if (PrintMiscellaneous && Verbose) {
1002 warning("AddAce failure: lasterror = %d \n", GetLastError());
1003 }
1004 FREE_C_HEAP_ARRAY(char, newACL);
1005 return false;
1006 }
1007 ace_index++;
1008 }
1009 }
1010
1011 // add the new ACL to the security descriptor.
1012 if (!SetSecurityDescriptorDacl(pSD, TRUE, newACL, FALSE)) {
1013 if (PrintMiscellaneous && Verbose) {
1014 warning("SetSecurityDescriptorDacl failure:"
1015 " lasterror = %d \n", GetLastError());
1016 }
1017 FREE_C_HEAP_ARRAY(char, newACL);
1018 return false;
1019 }
1020
1021 // if running on windows 2000 or later, set the automatic inheritance
1022 // control flags.
1023 SetSecurityDescriptorControlFnPtr _SetSecurityDescriptorControl;
1024 _SetSecurityDescriptorControl = (SetSecurityDescriptorControlFnPtr)
1025 GetProcAddress(GetModuleHandle(TEXT("advapi32.dll")),
1026 "SetSecurityDescriptorControl");
1027
1028 if (_SetSecurityDescriptorControl != NULL) {
1029 // We do not want to further propagate inherited DACLs, so making them
1030 // protected prevents that.
1031 if (!_SetSecurityDescriptorControl(pSD, SE_DACL_PROTECTED,
1032 SE_DACL_PROTECTED)) {
1033 if (PrintMiscellaneous && Verbose) {
1034 warning("SetSecurityDescriptorControl failure:"
1035 " lasterror = %d \n", GetLastError());
1036 }
1037 FREE_C_HEAP_ARRAY(char, newACL);
1038 return false;
1039 }
1040 }
1041 // Note, the security descriptor maintains a reference to the newACL, not
1042 // a copy of it. Therefore, the newACL is not freed here. It is freed when
1043 // the security descriptor containing its reference is freed.
1044 //
1045 return true;
1046 }
1047
1048 // method to create a security attributes structure, which contains a
1049 // security descriptor and an access control list comprised of 0 or more
1050 // access control entries. The method take an array of ace_data structures
1051 // that indicate the ACE to be added to the security descriptor.
1052 //
1053 // the caller must free the resources associated with the security
1054 // attributes structure created by this method by calling the
1055 // free_security_attr() method.
1056 //
1057 static LPSECURITY_ATTRIBUTES make_security_attr(ace_data_t aces[], int count) {
1058
1059 // allocate space for a security descriptor
1060 PSECURITY_DESCRIPTOR pSD = (PSECURITY_DESCRIPTOR)
1061 NEW_C_HEAP_ARRAY(char, SECURITY_DESCRIPTOR_MIN_LENGTH, mtInternal);
1062
1063 // initialize the security descriptor
1064 if (!InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION)) {
1065 if (PrintMiscellaneous && Verbose) {
1066 warning("InitializeSecurityDescriptor failure: "
1067 "lasterror = %d \n", GetLastError());
1068 }
1069 free_security_desc(pSD);
1070 return NULL;
1071 }
1072
1073 // add the access control entries
1074 if (!add_allow_aces(pSD, aces, count)) {
1075 free_security_desc(pSD);
1076 return NULL;
1077 }
1078
1079 // allocate and initialize the security attributes structure and
1080 // return it to the caller.
1081 //
1082 LPSECURITY_ATTRIBUTES lpSA = (LPSECURITY_ATTRIBUTES)
1083 NEW_C_HEAP_ARRAY(char, sizeof(SECURITY_ATTRIBUTES), mtInternal);
1084 lpSA->nLength = sizeof(SECURITY_ATTRIBUTES);
1085 lpSA->lpSecurityDescriptor = pSD;
1086 lpSA->bInheritHandle = FALSE;
1087
1088 return(lpSA);
1089 }
1090
1091 // method to create a security attributes structure with a restrictive
1092 // access control list that creates a set access rights for the user/owner
1093 // of the securable object and a separate set access rights for everyone else.
1094 // also provides for full access rights for the administrator group.
1095 //
1096 // the caller must free the resources associated with the security
1097 // attributes structure created by this method by calling the
1098 // free_security_attr() method.
1099 //
1100
1101 static LPSECURITY_ATTRIBUTES make_user_everybody_admin_security_attr(
1102 DWORD umask, DWORD emask, DWORD amask) {
1103
1104 ace_data_t aces[3];
1105
1106 // initialize the user ace data
1107 aces[0].pSid = get_user_sid(GetCurrentProcess());
1108 aces[0].mask = umask;
1109
1110 if (aces[0].pSid == 0)
1111 return NULL;
1112
1113 // get the well known SID for BUILTIN\Administrators
1114 PSID administratorsSid = NULL;
1115 SID_IDENTIFIER_AUTHORITY SIDAuthAdministrators = SECURITY_NT_AUTHORITY;
1116
1117 if (!AllocateAndInitializeSid( &SIDAuthAdministrators, 2,
1118 SECURITY_BUILTIN_DOMAIN_RID,
1119 DOMAIN_ALIAS_RID_ADMINS,
1120 0, 0, 0, 0, 0, 0, &administratorsSid)) {
1121
1122 if (PrintMiscellaneous && Verbose) {
1123 warning("AllocateAndInitializeSid failure: "
1124 "lasterror = %d \n", GetLastError());
1125 }
1126 return NULL;
1127 }
1128
1129 // initialize the ace data for administrator group
1130 aces[1].pSid = administratorsSid;
1131 aces[1].mask = amask;
1132
1133 // get the well known SID for the universal Everybody
1134 PSID everybodySid = NULL;
1135 SID_IDENTIFIER_AUTHORITY SIDAuthEverybody = SECURITY_WORLD_SID_AUTHORITY;
1136
1137 if (!AllocateAndInitializeSid( &SIDAuthEverybody, 1, SECURITY_WORLD_RID,
1138 0, 0, 0, 0, 0, 0, 0, &everybodySid)) {
1139
1140 if (PrintMiscellaneous && Verbose) {
1141 warning("AllocateAndInitializeSid failure: "
1142 "lasterror = %d \n", GetLastError());
1143 }
1144 return NULL;
1145 }
1146
1147 // initialize the ace data for everybody else.
1148 aces[2].pSid = everybodySid;
1149 aces[2].mask = emask;
1150
1151 // create a security attributes structure with access control
1152 // entries as initialized above.
1153 LPSECURITY_ATTRIBUTES lpSA = make_security_attr(aces, 3);
1154 FREE_C_HEAP_ARRAY(char, aces[0].pSid);
1155 FreeSid(everybodySid);
1156 FreeSid(administratorsSid);
1157 return(lpSA);
1158 }
1159
1160
1161 // method to create the security attributes structure for restricting
1162 // access to the user temporary directory.
1163 //
1164 // the caller must free the resources associated with the security
1165 // attributes structure created by this method by calling the
1166 // free_security_attr() method.
1167 //
1168 static LPSECURITY_ATTRIBUTES make_tmpdir_security_attr() {
1169
1170 // create full access rights for the user/owner of the directory
1171 // and read-only access rights for everybody else. This is
1172 // effectively equivalent to UNIX 755 permissions on a directory.
1173 //
1174 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_ALL_ACCESS;
1175 DWORD emask = GENERIC_READ | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1176 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1177
1178 return make_user_everybody_admin_security_attr(umask, emask, amask);
1179 }
1180
1181 // method to create the security attributes structure for restricting
1182 // access to the shared memory backing store file.
1183 //
1184 // the caller must free the resources associated with the security
1185 // attributes structure created by this method by calling the
1186 // free_security_attr() method.
1187 //
1188 static LPSECURITY_ATTRIBUTES make_file_security_attr() {
1189
1190 // create extensive access rights for the user/owner of the file
1191 // and attribute read-only access rights for everybody else. This
1192 // is effectively equivalent to UNIX 600 permissions on a file.
1193 //
1194 DWORD umask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1195 DWORD emask = STANDARD_RIGHTS_READ | FILE_READ_ATTRIBUTES |
1196 FILE_READ_EA | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1197 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1198
1199 return make_user_everybody_admin_security_attr(umask, emask, amask);
1200 }
1201
1202 // method to create the security attributes structure for restricting
1203 // access to the name shared memory file mapping object.
1204 //
1205 // the caller must free the resources associated with the security
1206 // attributes structure created by this method by calling the
1207 // free_security_attr() method.
1208 //
1209 static LPSECURITY_ATTRIBUTES make_smo_security_attr() {
1210
1211 // create extensive access rights for the user/owner of the shared
1212 // memory object and attribute read-only access rights for everybody
1213 // else. This is effectively equivalent to UNIX 600 permissions on
1214 // on the shared memory object.
1215 //
1216 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_MAP_ALL_ACCESS;
1217 DWORD emask = STANDARD_RIGHTS_READ; // attributes only
1218 DWORD amask = STANDARD_RIGHTS_ALL | FILE_MAP_ALL_ACCESS;
1219
1220 return make_user_everybody_admin_security_attr(umask, emask, amask);
1221 }
1222
1223 // make the user specific temporary directory
1224 //
1225 static bool make_user_tmp_dir(const char* dirname) {
1226
1227
1228 LPSECURITY_ATTRIBUTES pDirSA = make_tmpdir_security_attr();
1229 if (pDirSA == NULL) {
1230 return false;
1231 }
1232
1233
1234 // create the directory with the given security attributes
1235 if (!CreateDirectory(dirname, pDirSA)) {
1236 DWORD lasterror = GetLastError();
1237 if (lasterror == ERROR_ALREADY_EXISTS) {
1238 // The directory already exists and was probably created by another
1239 // JVM instance. However, this could also be the result of a
1240 // deliberate symlink. Verify that the existing directory is safe.
1241 //
1242 if (!is_directory_secure(dirname)) {
1243 // directory is not secure
1244 if (PrintMiscellaneous && Verbose) {
1245 warning("%s directory is insecure\n", dirname);
1246 }
1247 return false;
1248 }
1249 // The administrator should be able to delete this directory.
1250 // But the directory created by previous version of JVM may not
1251 // have permission for administrators to delete this directory.
1252 // So add full permission to the administrator. Also setting new
1253 // DACLs might fix the corrupted the DACLs.
1254 SECURITY_INFORMATION secInfo = DACL_SECURITY_INFORMATION;
1255 if (!SetFileSecurity(dirname, secInfo, pDirSA->lpSecurityDescriptor)) {
1256 if (PrintMiscellaneous && Verbose) {
1257 lasterror = GetLastError();
1258 warning("SetFileSecurity failed for %s directory. lasterror %d \n",
1259 dirname, lasterror);
1260 }
1261 }
1262 }
1263 else {
1264 if (PrintMiscellaneous && Verbose) {
1265 warning("CreateDirectory failed: %d\n", GetLastError());
1266 }
1267 return false;
1268 }
1269 }
1270
1271 // free the security attributes structure
1272 free_security_attr(pDirSA);
1273
1274 return true;
1275 }
1276
1277 // create the shared memory resources
1278 //
1279 // This function creates the shared memory resources. This includes
1280 // the backing store file and the file mapping shared memory object.
1281 //
1282 static HANDLE create_sharedmem_resources(const char* dirname, const char* filename, const char* objectname, size_t size) {
1283
1284 HANDLE fh = INVALID_HANDLE_VALUE;
1285 HANDLE fmh = NULL;
1286
1287
1288 // create the security attributes for the backing store file
1289 LPSECURITY_ATTRIBUTES lpFileSA = make_file_security_attr();
1290 if (lpFileSA == NULL) {
1291 return NULL;
1292 }
1293
1294 // create the security attributes for the shared memory object
1295 LPSECURITY_ATTRIBUTES lpSmoSA = make_smo_security_attr();
1296 if (lpSmoSA == NULL) {
1297 free_security_attr(lpFileSA);
1298 return NULL;
1299 }
1300
1301 // create the user temporary directory
1302 if (!make_user_tmp_dir(dirname)) {
1303 // could not make/find the directory or the found directory
1304 // was not secure
1305 return NULL;
1306 }
1307
1308 // Create the file - the FILE_FLAG_DELETE_ON_CLOSE flag allows the
1309 // file to be deleted by the last process that closes its handle to
1310 // the file. This is important as the apis do not allow a terminating
1311 // JVM being monitored by another process to remove the file name.
1312 //
1313 fh = CreateFile(
1314 filename, /* LPCTSTR file name */
1315
1316 GENERIC_READ|GENERIC_WRITE, /* DWORD desired access */
1317 FILE_SHARE_DELETE|FILE_SHARE_READ, /* DWORD share mode, future READONLY
1318 * open operations allowed
1319 */
1320 lpFileSA, /* LPSECURITY security attributes */
1321 CREATE_ALWAYS, /* DWORD creation disposition
1322 * create file, if it already
1323 * exists, overwrite it.
1324 */
1325 FILE_FLAG_DELETE_ON_CLOSE, /* DWORD flags and attributes */
1326
1327 NULL); /* HANDLE template file access */
1328
1329 free_security_attr(lpFileSA);
1330
1331 if (fh == INVALID_HANDLE_VALUE) {
1332 DWORD lasterror = GetLastError();
1333 if (PrintMiscellaneous && Verbose) {
1334 warning("could not create file %s: %d\n", filename, lasterror);
1335 }
1336 return NULL;
1337 }
1338
1339 // try to create the file mapping
1340 fmh = create_file_mapping(objectname, fh, lpSmoSA, size);
1341
1342 free_security_attr(lpSmoSA);
1343
1344 if (fmh == NULL) {
1345 // closing the file handle here will decrement the reference count
1346 // on the file. When all processes accessing the file close their
1347 // handle to it, the reference count will decrement to 0 and the
1348 // OS will delete the file. These semantics are requested by the
1349 // FILE_FLAG_DELETE_ON_CLOSE flag in CreateFile call above.
1350 CloseHandle(fh);
1351 fh = NULL;
1352 return NULL;
1353 } else {
1354 // We created the file mapping, but rarely the size of the
1355 // backing store file is reported as zero (0) which can cause
1356 // failures when trying to use the hsperfdata file.
1357 struct stat statbuf;
1358 int ret_code = ::stat(filename, &statbuf);
1359 if (ret_code == OS_ERR) {
1360 if (PrintMiscellaneous && Verbose) {
1361 warning("Could not get status information from file %s: %s\n",
1362 filename, os::strerror(errno));
1363 }
1364 CloseHandle(fmh);
1365 CloseHandle(fh);
1366 fh = NULL;
1367 fmh = NULL;
1368 return NULL;
1369 }
1370
1371 // We could always call FlushFileBuffers() but the Microsoft
1372 // docs indicate that it is considered expensive so we only
1373 // call it when we observe the size as zero (0).
1374 if (statbuf.st_size == 0 && FlushFileBuffers(fh) != TRUE) {
1375 DWORD lasterror = GetLastError();
1376 if (PrintMiscellaneous && Verbose) {
1377 warning("could not flush file %s: %d\n", filename, lasterror);
1378 }
1379 CloseHandle(fmh);
1380 CloseHandle(fh);
1381 fh = NULL;
1382 fmh = NULL;
1383 return NULL;
1384 }
1385 }
1386
1387 // the file has been successfully created and the file mapping
1388 // object has been created.
1389 sharedmem_fileHandle = fh;
1390 sharedmem_fileName = os::strdup(filename);
1391
1392 return fmh;
1393 }
1394
1395 // open the shared memory object for the given vmid.
1396 //
1397 static HANDLE open_sharedmem_object(const char* objectname, DWORD ofm_access, TRAPS) {
1398
1399 HANDLE fmh;
1400
1401 // open the file mapping with the requested mode
1402 fmh = OpenFileMapping(
1403 ofm_access, /* DWORD access mode */
1404 FALSE, /* BOOL inherit flag - Do not allow inherit */
1405 objectname); /* name for object */
1406
1407 if (fmh == NULL) {
1408 DWORD lasterror = GetLastError();
1409 if (PrintMiscellaneous && Verbose) {
1410 warning("OpenFileMapping failed for shared memory object %s:"
1411 " lasterror = %d\n", objectname, lasterror);
1412 }
1413 THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
1414 err_msg("Could not open PerfMemory, error %d", lasterror),
1415 INVALID_HANDLE_VALUE);
1416 }
1417
1418 return fmh;;
1419 }
1420
1421 // create a named shared memory region
1422 //
1423 // On Win32, a named shared memory object has a name space that
1424 // is independent of the file system name space. Shared memory object,
1425 // or more precisely, file mapping objects, provide no mechanism to
1426 // inquire the size of the memory region. There is also no api to
1427 // enumerate the memory regions for various processes.
1428 //
1429 // This implementation utilizes the shared memory name space in parallel
1430 // with the file system name space. This allows us to determine the
1431 // size of the shared memory region from the size of the file and it
1432 // allows us to provide a common, file system based name space for
1433 // shared memory across platforms.
1434 //
1435 static char* mapping_create_shared(size_t size) {
1436
1437 void *mapAddress;
1438 int vmid = os::current_process_id();
1439
1440 // get the name of the user associated with this process
1441 char* user = get_user_name();
1442
1443 if (user == NULL) {
1444 return NULL;
1445 }
1446
1447 // construct the name of the user specific temporary directory
1448 char* dirname = get_user_tmp_dir(user);
1449
1450 // check that the file system is secure - i.e. it supports ACLs.
1451 if (!is_filesystem_secure(dirname)) {
1452 FREE_C_HEAP_ARRAY(char, dirname);
1453 FREE_C_HEAP_ARRAY(char, user);
1454 return NULL;
1455 }
1456
1457 // create the names of the backing store files and for the
1458 // share memory object.
1459 //
1460 char* filename = get_sharedmem_filename(dirname, vmid);
1461 char* objectname = get_sharedmem_objectname(user, vmid);
1462
1463 // cleanup any stale shared memory resources
1464 cleanup_sharedmem_resources(dirname);
1465
1466 assert(((size != 0) && (size % os::vm_page_size() == 0)),
1467 "unexpected PerfMemry region size");
1468
1469 FREE_C_HEAP_ARRAY(char, user);
1470
1471 // create the shared memory resources
1472 sharedmem_fileMapHandle =
1473 create_sharedmem_resources(dirname, filename, objectname, size);
1474
1475 FREE_C_HEAP_ARRAY(char, filename);
1476 FREE_C_HEAP_ARRAY(char, objectname);
1477 FREE_C_HEAP_ARRAY(char, dirname);
1478
1479 if (sharedmem_fileMapHandle == NULL) {
1480 return NULL;
1481 }
1482
1483 // map the file into the address space
1484 mapAddress = MapViewOfFile(
1485 sharedmem_fileMapHandle, /* HANDLE = file mapping object */
1486 FILE_MAP_ALL_ACCESS, /* DWORD access flags */
1487 0, /* DWORD High word of offset */
1488 0, /* DWORD Low word of offset */
1489 (DWORD)size); /* DWORD Number of bytes to map */
1490
1491 if (mapAddress == NULL) {
1492 if (PrintMiscellaneous && Verbose) {
1493 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1494 }
1495 CloseHandle(sharedmem_fileMapHandle);
1496 sharedmem_fileMapHandle = NULL;
1497 return NULL;
1498 }
1499
1500 // clear the shared memory region
1501 (void)memset(mapAddress, '\0', size);
1502
1503 // it does not go through os api, the operation has to record from here
1504 MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress,
1505 size, CURRENT_PC, mtInternal);
1506
1507 return (char*) mapAddress;
1508 }
1509
1510 // this method deletes the file mapping object.
1511 //
1512 static void delete_file_mapping(char* addr, size_t size) {
1513
1514 // cleanup the persistent shared memory resources. since DestroyJavaVM does
1515 // not support unloading of the JVM, unmapping of the memory resource is not
1516 // performed. The memory will be reclaimed by the OS upon termination of all
1517 // processes mapping the resource. The file mapping handle and the file
1518 // handle are closed here to expedite the remove of the file by the OS. The
1519 // file is not removed directly because it was created with
1520 // FILE_FLAG_DELETE_ON_CLOSE semantics and any attempt to remove it would
1521 // be unsuccessful.
1522
1523 // close the fileMapHandle. the file mapping will still be retained
1524 // by the OS as long as any other JVM processes has an open file mapping
1525 // handle or a mapped view of the file.
1526 //
1527 if (sharedmem_fileMapHandle != NULL) {
1528 CloseHandle(sharedmem_fileMapHandle);
1529 sharedmem_fileMapHandle = NULL;
1530 }
1531
1532 // close the file handle. This will decrement the reference count on the
1533 // backing store file. When the reference count decrements to 0, the OS
1534 // will delete the file. These semantics apply because the file was
1535 // created with the FILE_FLAG_DELETE_ON_CLOSE flag.
1536 //
1537 if (sharedmem_fileHandle != INVALID_HANDLE_VALUE) {
1538 CloseHandle(sharedmem_fileHandle);
1539 sharedmem_fileHandle = INVALID_HANDLE_VALUE;
1540 }
1541 }
1542
1543 // this method determines the size of the shared memory file
1544 //
1545 static size_t sharedmem_filesize(const char* filename, TRAPS) {
1546
1547 struct stat statbuf;
1548
1549 // get the file size
1550 //
1551 // on win95/98/me, _stat returns a file size of 0 bytes, but on
1552 // winnt/2k the appropriate file size is returned. support for
1553 // the sharable aspects of performance counters was abandonded
1554 // on the non-nt win32 platforms due to this and other api
1555 // inconsistencies
1556 //
1557 if (::stat(filename, &statbuf) == OS_ERR) {
1558 if (PrintMiscellaneous && Verbose) {
1559 warning("stat %s failed: %s\n", filename, os::strerror(errno));
1560 }
1561 THROW_MSG_0(vmSymbols::java_io_IOException(),
1562 "Could not determine PerfMemory size");
1563 }
1564
1565 if ((statbuf.st_size == 0) || (statbuf.st_size % os::vm_page_size() != 0)) {
1566 if (PrintMiscellaneous && Verbose) {
1567 warning("unexpected file size: size = " SIZE_FORMAT "\n",
1568 statbuf.st_size);
1569 }
1570 THROW_MSG_0(vmSymbols::java_lang_Exception(),
1571 "Invalid PerfMemory size");
1572 }
1573
1574 return statbuf.st_size;
1575 }
1576
1577 // this method opens a file mapping object and maps the object
1578 // into the address space of the process
1579 //
1580 static void open_file_mapping(const char* user, int vmid,
1581 PerfMemory::PerfMemoryMode mode,
1582 char** addrp, size_t* sizep, TRAPS) {
1583
1584 ResourceMark rm;
1585
1586 void *mapAddress = 0;
1587 size_t size = 0;
1588 HANDLE fmh;
1589 DWORD ofm_access;
1590 DWORD mv_access;
1591 const char* luser = NULL;
1592
1593 if (mode == PerfMemory::PERF_MODE_RO) {
1594 ofm_access = FILE_MAP_READ;
1595 mv_access = FILE_MAP_READ;
1596 }
1597 else if (mode == PerfMemory::PERF_MODE_RW) {
1598 #ifdef LATER
1599 ofm_access = FILE_MAP_READ | FILE_MAP_WRITE;
1600 mv_access = FILE_MAP_READ | FILE_MAP_WRITE;
1601 #else
1602 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1603 "Unsupported access mode");
1604 #endif
1605 }
1606 else {
1607 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1608 "Illegal access mode");
1609 }
1610
1611 // if a user name wasn't specified, then find the user name for
1612 // the owner of the target vm.
1613 if (user == NULL || strlen(user) == 0) {
1614 luser = get_user_name(vmid);
1615 }
1616 else {
1617 luser = user;
1618 }
1619
1620 if (luser == NULL) {
1621 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1622 "Could not map vmid to user name");
1623 }
1624
1625 // get the names for the resources for the target vm
1626 char* dirname = get_user_tmp_dir(luser);
1627
1628 // since we don't follow symbolic links when creating the backing
1629 // store file, we also don't following them when attaching
1630 //
1631 if (!is_directory_secure(dirname)) {
1632 FREE_C_HEAP_ARRAY(char, dirname);
1633 if (luser != user) FREE_C_HEAP_ARRAY(char, luser);
1634 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1635 "Process not found");
1636 }
1637
1638 char* filename = get_sharedmem_filename(dirname, vmid);
1639 char* objectname = get_sharedmem_objectname(luser, vmid);
1640
1641 // copy heap memory to resource memory. the objectname and
1642 // filename are passed to methods that may throw exceptions.
1643 // using resource arrays for these names prevents the leaks
1644 // that would otherwise occur.
1645 //
1646 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
1647 char* robjectname = NEW_RESOURCE_ARRAY(char, strlen(objectname) + 1);
1648 strcpy(rfilename, filename);
1649 strcpy(robjectname, objectname);
1650
1651 // free the c heap resources that are no longer needed
1652 if (luser != user) FREE_C_HEAP_ARRAY(char, luser);
1653 FREE_C_HEAP_ARRAY(char, dirname);
1654 FREE_C_HEAP_ARRAY(char, filename);
1655 FREE_C_HEAP_ARRAY(char, objectname);
1656
1657 if (*sizep == 0) {
1658 size = sharedmem_filesize(rfilename, CHECK);
1659 } else {
1660 size = *sizep;
1661 }
1662
1663 assert(size > 0, "unexpected size <= 0");
1664
1665 // Open the file mapping object with the given name
1666 fmh = open_sharedmem_object(robjectname, ofm_access, CHECK);
1667
1668 assert(fmh != INVALID_HANDLE_VALUE, "unexpected handle value");
1669
1670 // map the entire file into the address space
1671 mapAddress = MapViewOfFile(
1672 fmh, /* HANDLE Handle of file mapping object */
1673 mv_access, /* DWORD access flags */
1674 0, /* DWORD High word of offset */
1675 0, /* DWORD Low word of offset */
1676 size); /* DWORD Number of bytes to map */
1677
1678 if (mapAddress == NULL) {
1679 if (PrintMiscellaneous && Verbose) {
1680 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1681 }
1682 CloseHandle(fmh);
1683 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
1684 "Could not map PerfMemory");
1685 }
1686
1687 // it does not go through os api, the operation has to record from here
1688 MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress, size,
1689 CURRENT_PC, mtInternal);
1690
1691
1692 *addrp = (char*)mapAddress;
1693 *sizep = size;
1694
1695 // File mapping object can be closed at this time without
1696 // invalidating the mapped view of the file
1697 CloseHandle(fmh);
1698
1699 log_debug(perf, memops)("mapped " SIZE_FORMAT " bytes for vmid %d at "
1700 INTPTR_FORMAT "\n", size, vmid, mapAddress);
1701 }
1702
1703 // this method unmaps the the mapped view of the the
1704 // file mapping object.
1705 //
1706 static void remove_file_mapping(char* addr) {
1707
1708 // the file mapping object was closed in open_file_mapping()
1709 // after the file map view was created. We only need to
1710 // unmap the file view here.
1711 UnmapViewOfFile(addr);
1712 }
1713
1714 // create the PerfData memory region in shared memory.
1715 static char* create_shared_memory(size_t size) {
1716
1717 return mapping_create_shared(size);
1718 }
1719
1720 // release a named, shared memory region
1721 //
1722 void delete_shared_memory(char* addr, size_t size) {
1723
1724 delete_file_mapping(addr, size);
1725 }
1726
1727
1728
1729
1730 // create the PerfData memory region
1731 //
1732 // This method creates the memory region used to store performance
1733 // data for the JVM. The memory may be created in standard or
1734 // shared memory.
1735 //
1736 void PerfMemory::create_memory_region(size_t size) {
1737
1738 if (PerfDisableSharedMem) {
1739 // do not share the memory for the performance data.
1740 PerfDisableSharedMem = true;
1741 _start = create_standard_memory(size);
1742 }
1743 else {
1744 _start = create_shared_memory(size);
1745 if (_start == NULL) {
1746
1747 // creation of the shared memory region failed, attempt
1748 // to create a contiguous, non-shared memory region instead.
1749 //
1750 if (PrintMiscellaneous && Verbose) {
1751 warning("Reverting to non-shared PerfMemory region.\n");
1752 }
1753 PerfDisableSharedMem = true;
1754 _start = create_standard_memory(size);
1755 }
1756 }
1757
1758 if (_start != NULL) _capacity = size;
1759
1760 }
1761
1762 // delete the PerfData memory region
1763 //
1764 // This method deletes the memory region used to store performance
1765 // data for the JVM. The memory region indicated by the <address, size>
1766 // tuple will be inaccessible after a call to this method.
1767 //
1768 void PerfMemory::delete_memory_region() {
1769
1770 assert((start() != NULL && capacity() > 0), "verify proper state");
1771
1772 // If user specifies PerfDataSaveFile, it will save the performance data
1773 // to the specified file name no matter whether PerfDataSaveToFile is specified
1774 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
1775 // -XX:+PerfDataSaveToFile.
1776 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
1777 save_memory_to_file(start(), capacity());
1778 }
1779
1780 if (PerfDisableSharedMem) {
1781 delete_standard_memory(start(), capacity());
1782 }
1783 else {
1784 delete_shared_memory(start(), capacity());
1785 }
1786 }
1787
1788 // attach to the PerfData memory region for another JVM
1789 //
1790 // This method returns an <address, size> tuple that points to
1791 // a memory buffer that is kept reasonably synchronized with
1792 // the PerfData memory region for the indicated JVM. This
1793 // buffer may be kept in synchronization via shared memory
1794 // or some other mechanism that keeps the buffer updated.
1795 //
1796 // If the JVM chooses not to support the attachability feature,
1797 // this method should throw an UnsupportedOperation exception.
1798 //
1799 // This implementation utilizes named shared memory to map
1800 // the indicated process's PerfData memory region into this JVMs
1801 // address space.
1802 //
1803 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode,
1804 char** addrp, size_t* sizep, TRAPS) {
1805
1806 if (vmid == 0 || vmid == os::current_process_id()) {
1807 *addrp = start();
1808 *sizep = capacity();
1809 return;
1810 }
1811
1812 open_file_mapping(user, vmid, mode, addrp, sizep, CHECK);
1813 }
1814
1815 // detach from the PerfData memory region of another JVM
1816 //
1817 // This method detaches the PerfData memory region of another
1818 // JVM, specified as an <address, size> tuple of a buffer
1819 // in this process's address space. This method may perform
1820 // arbitrary actions to accomplish the detachment. The memory
1821 // region specified by <address, size> will be inaccessible after
1822 // a call to this method.
1823 //
1824 // If the JVM chooses not to support the attachability feature,
1825 // this method should throw an UnsupportedOperation exception.
1826 //
1827 // This implementation utilizes named shared memory to detach
1828 // the indicated process's PerfData memory region from this
1829 // process's address space.
1830 //
1831 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
1832
1833 assert(addr != 0, "address sanity check");
1834 assert(bytes > 0, "capacity sanity check");
1835
1836 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
1837 // prevent accidental detachment of this process's PerfMemory region
1838 return;
1839 }
1840
1841 if (MemTracker::tracking_level() > NMT_minimal) {
1842 // it does not go through os api, the operation has to record from here
1843 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1844 remove_file_mapping(addr);
1845 tkr.record((address)addr, bytes);
1846 } else {
1847 remove_file_mapping(addr);
1848 }
1849 }