1 /*
2 * Copyright (c) 2001, 2018, 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 //
create_standard_memory(size_t size)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 //
delete_standard_memory(char * addr,size_t size)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 //
save_memory_to_file(char * addr,size_t size)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 //
get_user_tmp_dir(const char * user)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 //
filename_to_pid(const char * filename)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 //
is_directory_secure(const char * path)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 //
get_user_name()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 //
get_user_name_slow(int vmid)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 errno = 0;
322 while ((dentry = os::readdir(tmpdirp)) != NULL) {
323
324 // check if the directory entry is a hsperfdata file
325 if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
326 continue;
327 }
328
329 char* usrdir_name = NEW_C_HEAP_ARRAY(char,
330 strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal);
331 strcpy(usrdir_name, tmpdirname);
332 strcat(usrdir_name, "\\");
333 strcat(usrdir_name, dentry->d_name);
334
335 DIR* subdirp = os::opendir(usrdir_name);
336
337 if (subdirp == NULL) {
338 FREE_C_HEAP_ARRAY(char, usrdir_name);
339 continue;
340 }
341
342 // Since we don't create the backing store files in directories
343 // pointed to by symbolic links, we also don't follow them when
344 // looking for the files. We check for a symbolic link after the
345 // call to opendir in order to eliminate a small window where the
346 // symlink can be exploited.
347 //
348 if (!is_directory_secure(usrdir_name)) {
349 FREE_C_HEAP_ARRAY(char, usrdir_name);
350 os::closedir(subdirp);
351 continue;
352 }
353
354 struct dirent* udentry;
355 errno = 0;
356 while ((udentry = os::readdir(subdirp)) != NULL) {
357
358 if (filename_to_pid(udentry->d_name) == vmid) {
359 struct stat statbuf;
360
361 char* filename = NEW_C_HEAP_ARRAY(char,
362 strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal);
363
364 strcpy(filename, usrdir_name);
365 strcat(filename, "\\");
366 strcat(filename, udentry->d_name);
367
368 if (::stat(filename, &statbuf) == OS_ERR) {
369 FREE_C_HEAP_ARRAY(char, filename);
370 continue;
371 }
372
373 // skip over files that are not regular files.
374 if ((statbuf.st_mode & S_IFMT) != S_IFREG) {
375 FREE_C_HEAP_ARRAY(char, filename);
376 continue;
377 }
378
379 // If we found a matching file with a newer creation time, then
380 // save the user name. The newer creation time indicates that
381 // we found a newer incarnation of the process associated with
382 // vmid. Due to the way that Windows recycles pids and the fact
383 // that we can't delete the file from the file system namespace
384 // until last close, it is possible for there to be more than
385 // one hsperfdata file with a name matching vmid (diff users).
386 //
387 // We no longer ignore hsperfdata files where (st_size == 0).
388 // In this function, all we're trying to do is determine the
389 // name of the user that owns the process associated with vmid
390 // so the size doesn't matter. Very rarely, we have observed
391 // hsperfdata files where (st_size == 0) and the st_size field
392 // later becomes the expected value.
393 //
394 if (statbuf.st_ctime > latest_ctime) {
395 char* user = strchr(dentry->d_name, '_') + 1;
396
397 if (latest_user != NULL) FREE_C_HEAP_ARRAY(char, latest_user);
398 latest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
399
400 strcpy(latest_user, user);
401 latest_ctime = statbuf.st_ctime;
402 }
403
404 FREE_C_HEAP_ARRAY(char, filename);
405 }
406 }
407 os::closedir(subdirp);
408 FREE_C_HEAP_ARRAY(char, usrdir_name);
409 }
410 os::closedir(tmpdirp);
411
412 return(latest_user);
413 }
414
415 // return the name of the user that owns the process identified by vmid.
416 //
417 // note: this method should only be used via the Perf native methods.
418 // There are various costs to this method and limiting its use to the
419 // Perf native methods limits the impact to monitoring applications only.
420 //
get_user_name(int vmid)421 static char* get_user_name(int vmid) {
422
423 // A fast implementation is not provided at this time. It's possible
424 // to provide a fast process id to user name mapping function using
425 // the win32 apis, but the default ACL for the process object only
426 // allows processes with the same owner SID to acquire the process
427 // handle (via OpenProcess(PROCESS_QUERY_INFORMATION)). It's possible
428 // to have the JVM change the ACL for the process object to allow arbitrary
429 // users to access the process handle and the process security token.
430 // The security ramifications need to be studied before providing this
431 // mechanism.
432 //
433 return get_user_name_slow(vmid);
434 }
435
436 // return the name of the shared memory file mapping object for the
437 // named shared memory region for the given user name and vmid.
438 //
439 // The file mapping object's name is not the file name. It is a name
440 // in a separate name space.
441 //
442 // the caller is expected to free the allocated memory.
443 //
get_sharedmem_objectname(const char * user,int vmid)444 static char *get_sharedmem_objectname(const char* user, int vmid) {
445
446 // construct file mapping object's name, add 3 for two '_' and a
447 // null terminator.
448 int nbytes = (int)strlen(PERFDATA_NAME) + (int)strlen(user) + 3;
449
450 // the id is converted to an unsigned value here because win32 allows
451 // negative process ids. However, OpenFileMapping API complains
452 // about a name containing a '-' characters.
453 //
454 nbytes += UINT_CHARS;
455 char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
456 _snprintf(name, nbytes, "%s_%s_%u", PERFDATA_NAME, user, vmid);
457
458 return name;
459 }
460
461 // return the file name of the backing store file for the named
462 // shared memory region for the given user name and vmid.
463 //
464 // the caller is expected to free the allocated memory.
465 //
get_sharedmem_filename(const char * dirname,int vmid)466 static char* get_sharedmem_filename(const char* dirname, int vmid) {
467
468 // add 2 for the file separator and a null terminator.
469 size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
470
471 char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
472 _snprintf(name, nbytes, "%s\\%d", dirname, vmid);
473
474 return name;
475 }
476
477 // remove file
478 //
479 // this method removes the file with the given file name.
480 //
481 // Note: if the indicated file is on an SMB network file system, this
482 // method may be unsuccessful in removing the file.
483 //
remove_file(const char * dirname,const char * filename)484 static void remove_file(const char* dirname, const char* filename) {
485
486 size_t nbytes = strlen(dirname) + strlen(filename) + 2;
487 char* path = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
488
489 strcpy(path, dirname);
490 strcat(path, "\\");
491 strcat(path, filename);
492
493 if (::unlink(path) == OS_ERR) {
494 if (PrintMiscellaneous && Verbose) {
495 if (errno != ENOENT) {
496 warning("Could not unlink shared memory backing"
497 " store file %s : %s\n", path, os::strerror(errno));
498 }
499 }
500 }
501
502 FREE_C_HEAP_ARRAY(char, path);
503 }
504
505 // returns true if the process represented by pid is alive, otherwise
506 // returns false. the validity of the result is only accurate if the
507 // target process is owned by the same principal that owns this process.
508 // this method should not be used if to test the status of an otherwise
509 // arbitrary process unless it is know that this process has the appropriate
510 // privileges to guarantee a result valid.
511 //
is_alive(int pid)512 static bool is_alive(int pid) {
513
514 HANDLE ph = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);
515 if (ph == NULL) {
516 // the process does not exist.
517 if (PrintMiscellaneous && Verbose) {
518 DWORD lastError = GetLastError();
519 if (lastError != ERROR_INVALID_PARAMETER) {
520 warning("OpenProcess failed: %d\n", GetLastError());
521 }
522 }
523 return false;
524 }
525
526 DWORD exit_status;
527 if (!GetExitCodeProcess(ph, &exit_status)) {
528 if (PrintMiscellaneous && Verbose) {
529 warning("GetExitCodeProcess failed: %d\n", GetLastError());
530 }
531 CloseHandle(ph);
532 return false;
533 }
534
535 CloseHandle(ph);
536 return (exit_status == STILL_ACTIVE) ? true : false;
537 }
538
539 // check if the file system is considered secure for the backing store files
540 //
is_filesystem_secure(const char * path)541 static bool is_filesystem_secure(const char* path) {
542
543 char root_path[MAX_PATH];
544 char fs_type[MAX_PATH];
545
546 if (PerfBypassFileSystemCheck) {
547 if (PrintMiscellaneous && Verbose) {
548 warning("bypassing file system criteria checks for %s\n", path);
549 }
550 return true;
551 }
552
553 char* first_colon = strchr((char *)path, ':');
554 if (first_colon == NULL) {
555 if (PrintMiscellaneous && Verbose) {
556 warning("expected device specifier in path: %s\n", path);
557 }
558 return false;
559 }
560
561 size_t len = (size_t)(first_colon - path);
562 assert(len + 2 <= MAX_PATH, "unexpected device specifier length");
563 strncpy(root_path, path, len + 1);
564 root_path[len + 1] = '\\';
565 root_path[len + 2] = '\0';
566
567 // check that we have something like "C:\" or "AA:\"
568 assert(strlen(root_path) >= 3, "device specifier too short");
569 assert(strchr(root_path, ':') != NULL, "bad device specifier format");
570 assert(strchr(root_path, '\\') != NULL, "bad device specifier format");
571
572 DWORD maxpath;
573 DWORD flags;
574
575 if (!GetVolumeInformation(root_path, NULL, 0, NULL, &maxpath,
576 &flags, fs_type, MAX_PATH)) {
577 // we can't get information about the volume, so assume unsafe.
578 if (PrintMiscellaneous && Verbose) {
579 warning("could not get device information for %s: "
580 " path = %s: lasterror = %d\n",
581 root_path, path, GetLastError());
582 }
583 return false;
584 }
585
586 if ((flags & FS_PERSISTENT_ACLS) == 0) {
587 // file system doesn't support ACLs, declare file system unsafe
588 if (PrintMiscellaneous && Verbose) {
589 warning("file system type %s on device %s does not support"
590 " ACLs\n", fs_type, root_path);
591 }
592 return false;
593 }
594
595 if ((flags & FS_VOL_IS_COMPRESSED) != 0) {
596 // file system is compressed, declare file system unsafe
597 if (PrintMiscellaneous && Verbose) {
598 warning("file system type %s on device %s is compressed\n",
599 fs_type, root_path);
600 }
601 return false;
602 }
603
604 return true;
605 }
606
607 // cleanup stale shared memory resources
608 //
609 // This method attempts to remove all stale shared memory files in
610 // the named user temporary directory. It scans the named directory
611 // for files matching the pattern ^$[0-9]*$. For each file found, the
612 // process id is extracted from the file name and a test is run to
613 // determine if the process is alive. If the process is not alive,
614 // any stale file resources are removed.
615 //
cleanup_sharedmem_resources(const char * dirname)616 static void cleanup_sharedmem_resources(const char* dirname) {
617
618 // open the user temp directory
619 DIR* dirp = os::opendir(dirname);
620
621 if (dirp == NULL) {
622 // directory doesn't exist, so there is nothing to cleanup
623 return;
624 }
625
626 if (!is_directory_secure(dirname)) {
627 // the directory is not secure, don't attempt any cleanup
628 os::closedir(dirp);
629 return;
630 }
631
632 // for each entry in the directory that matches the expected file
633 // name pattern, determine if the file resources are stale and if
634 // so, remove the file resources. Note, instrumented HotSpot processes
635 // for this user may start and/or terminate during this search and
636 // remove or create new files in this directory. The behavior of this
637 // loop under these conditions is dependent upon the implementation of
638 // opendir/readdir.
639 //
640 struct dirent* entry;
641 errno = 0;
642 while ((entry = os::readdir(dirp)) != NULL) {
643
644 int pid = filename_to_pid(entry->d_name);
645
646 if (pid == 0) {
647
648 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
649
650 // attempt to remove all unexpected files, except "." and ".."
651 remove_file(dirname, entry->d_name);
652 }
653
654 errno = 0;
655 continue;
656 }
657
658 // we now have a file name that converts to a valid integer
659 // that could represent a process id . if this process id
660 // matches the current process id or the process is not running,
661 // then remove the stale file resources.
662 //
663 // process liveness is detected by checking the exit status
664 // of the process. if the process id is valid and the exit status
665 // indicates that it is still running, the file file resources
666 // are not removed. If the process id is invalid, or if we don't
667 // have permissions to check the process status, or if the process
668 // id is valid and the process has terminated, the the file resources
669 // are assumed to be stale and are removed.
670 //
671 if (pid == os::current_process_id() || !is_alive(pid)) {
672
673 // we can only remove the file resources. Any mapped views
674 // of the file can only be unmapped by the processes that
675 // opened those views and the file mapping object will not
676 // get removed until all views are unmapped.
677 //
678 remove_file(dirname, entry->d_name);
679 }
680 errno = 0;
681 }
682 os::closedir(dirp);
683 }
684
685 // create a file mapping object with the requested name, and size
686 // from the file represented by the given Handle object
687 //
create_file_mapping(const char * name,HANDLE fh,LPSECURITY_ATTRIBUTES fsa,size_t size)688 static HANDLE create_file_mapping(const char* name, HANDLE fh, LPSECURITY_ATTRIBUTES fsa, size_t size) {
689
690 DWORD lowSize = (DWORD)size;
691 DWORD highSize = 0;
692 HANDLE fmh = NULL;
693
694 // Create a file mapping object with the given name. This function
695 // will grow the file to the specified size.
696 //
697 fmh = CreateFileMapping(
698 fh, /* HANDLE file handle for backing store */
699 fsa, /* LPSECURITY_ATTRIBUTES Not inheritable */
700 PAGE_READWRITE, /* DWORD protections */
701 highSize, /* DWORD High word of max size */
702 lowSize, /* DWORD Low word of max size */
703 name); /* LPCTSTR name for object */
704
705 if (fmh == NULL) {
706 if (PrintMiscellaneous && Verbose) {
707 warning("CreateFileMapping failed, lasterror = %d\n", GetLastError());
708 }
709 return NULL;
710 }
711
712 if (GetLastError() == ERROR_ALREADY_EXISTS) {
713
714 // a stale file mapping object was encountered. This object may be
715 // owned by this or some other user and cannot be removed until
716 // the other processes either exit or close their mapping objects
717 // and/or mapped views of this mapping object.
718 //
719 if (PrintMiscellaneous && Verbose) {
720 warning("file mapping already exists, lasterror = %d\n", GetLastError());
721 }
722
723 CloseHandle(fmh);
724 return NULL;
725 }
726
727 return fmh;
728 }
729
730
731 // method to free the given security descriptor and the contained
732 // access control list.
733 //
free_security_desc(PSECURITY_DESCRIPTOR pSD)734 static void free_security_desc(PSECURITY_DESCRIPTOR pSD) {
735
736 BOOL success, exists, isdefault;
737 PACL pACL;
738
739 if (pSD != NULL) {
740
741 // get the access control list from the security descriptor
742 success = GetSecurityDescriptorDacl(pSD, &exists, &pACL, &isdefault);
743
744 // if an ACL existed and it was not a default acl, then it must
745 // be an ACL we enlisted. free the resources.
746 //
747 if (success && exists && pACL != NULL && !isdefault) {
748 FREE_C_HEAP_ARRAY(char, pACL);
749 }
750
751 // free the security descriptor
752 FREE_C_HEAP_ARRAY(char, pSD);
753 }
754 }
755
756 // method to free up a security attributes structure and any
757 // contained security descriptors and ACL
758 //
free_security_attr(LPSECURITY_ATTRIBUTES lpSA)759 static void free_security_attr(LPSECURITY_ATTRIBUTES lpSA) {
760
761 if (lpSA != NULL) {
762 // free the contained security descriptor and the ACL
763 free_security_desc(lpSA->lpSecurityDescriptor);
764 lpSA->lpSecurityDescriptor = NULL;
765
766 // free the security attributes structure
767 FREE_C_HEAP_ARRAY(char, lpSA);
768 }
769 }
770
771 // get the user SID for the process indicated by the process handle
772 //
get_user_sid(HANDLE hProcess)773 static PSID get_user_sid(HANDLE hProcess) {
774
775 HANDLE hAccessToken;
776 PTOKEN_USER token_buf = NULL;
777 DWORD rsize = 0;
778
779 if (hProcess == NULL) {
780 return NULL;
781 }
782
783 // get the process token
784 if (!OpenProcessToken(hProcess, TOKEN_READ, &hAccessToken)) {
785 if (PrintMiscellaneous && Verbose) {
786 warning("OpenProcessToken failure: lasterror = %d \n", GetLastError());
787 }
788 return NULL;
789 }
790
791 // determine the size of the token structured needed to retrieve
792 // the user token information from the access token.
793 //
794 if (!GetTokenInformation(hAccessToken, TokenUser, NULL, rsize, &rsize)) {
795 DWORD lasterror = GetLastError();
796 if (lasterror != ERROR_INSUFFICIENT_BUFFER) {
797 if (PrintMiscellaneous && Verbose) {
798 warning("GetTokenInformation failure: lasterror = %d,"
799 " rsize = %d\n", lasterror, rsize);
800 }
801 CloseHandle(hAccessToken);
802 return NULL;
803 }
804 }
805
806 token_buf = (PTOKEN_USER) NEW_C_HEAP_ARRAY(char, rsize, mtInternal);
807
808 // get the user token information
809 if (!GetTokenInformation(hAccessToken, TokenUser, token_buf, rsize, &rsize)) {
810 if (PrintMiscellaneous && Verbose) {
811 warning("GetTokenInformation failure: lasterror = %d,"
812 " rsize = %d\n", GetLastError(), rsize);
813 }
814 FREE_C_HEAP_ARRAY(char, token_buf);
815 CloseHandle(hAccessToken);
816 return NULL;
817 }
818
819 DWORD nbytes = GetLengthSid(token_buf->User.Sid);
820 PSID pSID = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
821
822 if (!CopySid(nbytes, pSID, token_buf->User.Sid)) {
823 if (PrintMiscellaneous && Verbose) {
824 warning("GetTokenInformation failure: lasterror = %d,"
825 " rsize = %d\n", GetLastError(), rsize);
826 }
827 FREE_C_HEAP_ARRAY(char, token_buf);
828 FREE_C_HEAP_ARRAY(char, pSID);
829 CloseHandle(hAccessToken);
830 return NULL;
831 }
832
833 // close the access token.
834 CloseHandle(hAccessToken);
835 FREE_C_HEAP_ARRAY(char, token_buf);
836
837 return pSID;
838 }
839
840 // structure used to consolidate access control entry information
841 //
842 typedef struct ace_data {
843 PSID pSid; // SID of the ACE
844 DWORD mask; // mask for the ACE
845 } ace_data_t;
846
847
848 // method to add an allow access control entry with the access rights
849 // indicated in mask for the principal indicated in SID to the given
850 // security descriptor. Much of the DACL handling was adapted from
851 // the example provided here:
852 // http://support.microsoft.com/kb/102102/EN-US/
853 //
854
add_allow_aces(PSECURITY_DESCRIPTOR pSD,ace_data_t aces[],int ace_count)855 static bool add_allow_aces(PSECURITY_DESCRIPTOR pSD,
856 ace_data_t aces[], int ace_count) {
857 PACL newACL = NULL;
858 PACL oldACL = NULL;
859
860 if (pSD == NULL) {
861 return false;
862 }
863
864 BOOL exists, isdefault;
865
866 // retrieve any existing access control list.
867 if (!GetSecurityDescriptorDacl(pSD, &exists, &oldACL, &isdefault)) {
868 if (PrintMiscellaneous && Verbose) {
869 warning("GetSecurityDescriptor failure: lasterror = %d \n",
870 GetLastError());
871 }
872 return false;
873 }
874
875 // get the size of the DACL
876 ACL_SIZE_INFORMATION aclinfo;
877
878 // GetSecurityDescriptorDacl may return true value for exists (lpbDaclPresent)
879 // while oldACL is NULL for some case.
880 if (oldACL == NULL) {
881 exists = FALSE;
882 }
883
884 if (exists) {
885 if (!GetAclInformation(oldACL, &aclinfo,
886 sizeof(ACL_SIZE_INFORMATION),
887 AclSizeInformation)) {
888 if (PrintMiscellaneous && Verbose) {
889 warning("GetAclInformation failure: lasterror = %d \n", GetLastError());
890 return false;
891 }
892 }
893 } else {
894 aclinfo.AceCount = 0; // assume NULL DACL
895 aclinfo.AclBytesFree = 0;
896 aclinfo.AclBytesInUse = sizeof(ACL);
897 }
898
899 // compute the size needed for the new ACL
900 // initial size of ACL is sum of the following:
901 // * size of ACL structure.
902 // * size of each ACE structure that ACL is to contain minus the sid
903 // sidStart member (DWORD) of the ACE.
904 // * length of the SID that each ACE is to contain.
905 DWORD newACLsize = aclinfo.AclBytesInUse +
906 (sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD)) * ace_count;
907 for (int i = 0; i < ace_count; i++) {
908 assert(aces[i].pSid != 0, "pSid should not be 0");
909 newACLsize += GetLengthSid(aces[i].pSid);
910 }
911
912 // create the new ACL
913 newACL = (PACL) NEW_C_HEAP_ARRAY(char, newACLsize, mtInternal);
914
915 if (!InitializeAcl(newACL, newACLsize, ACL_REVISION)) {
916 if (PrintMiscellaneous && Verbose) {
917 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
918 }
919 FREE_C_HEAP_ARRAY(char, newACL);
920 return false;
921 }
922
923 unsigned int ace_index = 0;
924 // copy any existing ACEs from the old ACL (if any) to the new ACL.
925 if (aclinfo.AceCount != 0) {
926 while (ace_index < aclinfo.AceCount) {
927 LPVOID ace;
928 if (!GetAce(oldACL, ace_index, &ace)) {
929 if (PrintMiscellaneous && Verbose) {
930 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
931 }
932 FREE_C_HEAP_ARRAY(char, newACL);
933 return false;
934 }
935 if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceFlags && INHERITED_ACE) {
936 // this is an inherited, allowed ACE; break from loop so we can
937 // add the new access allowed, non-inherited ACE in the correct
938 // position, immediately following all non-inherited ACEs.
939 break;
940 }
941
942 // determine if the SID of this ACE matches any of the SIDs
943 // for which we plan to set ACEs.
944 int matches = 0;
945 for (int i = 0; i < ace_count; i++) {
946 if (EqualSid(aces[i].pSid, &(((ACCESS_ALLOWED_ACE *)ace)->SidStart))) {
947 matches++;
948 break;
949 }
950 }
951
952 // if there are no SID matches, then add this existing ACE to the new ACL
953 if (matches == 0) {
954 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
955 ((PACE_HEADER)ace)->AceSize)) {
956 if (PrintMiscellaneous && Verbose) {
957 warning("AddAce failure: lasterror = %d \n", GetLastError());
958 }
959 FREE_C_HEAP_ARRAY(char, newACL);
960 return false;
961 }
962 }
963 ace_index++;
964 }
965 }
966
967 // add the passed-in access control entries to the new ACL
968 for (int i = 0; i < ace_count; i++) {
969 if (!AddAccessAllowedAce(newACL, ACL_REVISION,
970 aces[i].mask, aces[i].pSid)) {
971 if (PrintMiscellaneous && Verbose) {
972 warning("AddAccessAllowedAce failure: lasterror = %d \n",
973 GetLastError());
974 }
975 FREE_C_HEAP_ARRAY(char, newACL);
976 return false;
977 }
978 }
979
980 // now copy the rest of the inherited ACEs from the old ACL
981 if (aclinfo.AceCount != 0) {
982 // picking up at ace_index, where we left off in the
983 // previous ace_index loop
984 while (ace_index < aclinfo.AceCount) {
985 LPVOID ace;
986 if (!GetAce(oldACL, ace_index, &ace)) {
987 if (PrintMiscellaneous && Verbose) {
988 warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
989 }
990 FREE_C_HEAP_ARRAY(char, newACL);
991 return false;
992 }
993 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
994 ((PACE_HEADER)ace)->AceSize)) {
995 if (PrintMiscellaneous && Verbose) {
996 warning("AddAce failure: lasterror = %d \n", GetLastError());
997 }
998 FREE_C_HEAP_ARRAY(char, newACL);
999 return false;
1000 }
1001 ace_index++;
1002 }
1003 }
1004
1005 // add the new ACL to the security descriptor.
1006 if (!SetSecurityDescriptorDacl(pSD, TRUE, newACL, FALSE)) {
1007 if (PrintMiscellaneous && Verbose) {
1008 warning("SetSecurityDescriptorDacl failure:"
1009 " lasterror = %d \n", GetLastError());
1010 }
1011 FREE_C_HEAP_ARRAY(char, newACL);
1012 return false;
1013 }
1014
1015 // if running on windows 2000 or later, set the automatic inheritance
1016 // control flags.
1017 SetSecurityDescriptorControlFnPtr _SetSecurityDescriptorControl;
1018 _SetSecurityDescriptorControl = (SetSecurityDescriptorControlFnPtr)
1019 GetProcAddress(GetModuleHandle(TEXT("advapi32.dll")),
1020 "SetSecurityDescriptorControl");
1021
1022 if (_SetSecurityDescriptorControl != NULL) {
1023 // We do not want to further propagate inherited DACLs, so making them
1024 // protected prevents that.
1025 if (!_SetSecurityDescriptorControl(pSD, SE_DACL_PROTECTED,
1026 SE_DACL_PROTECTED)) {
1027 if (PrintMiscellaneous && Verbose) {
1028 warning("SetSecurityDescriptorControl failure:"
1029 " lasterror = %d \n", GetLastError());
1030 }
1031 FREE_C_HEAP_ARRAY(char, newACL);
1032 return false;
1033 }
1034 }
1035 // Note, the security descriptor maintains a reference to the newACL, not
1036 // a copy of it. Therefore, the newACL is not freed here. It is freed when
1037 // the security descriptor containing its reference is freed.
1038 //
1039 return true;
1040 }
1041
1042 // method to create a security attributes structure, which contains a
1043 // security descriptor and an access control list comprised of 0 or more
1044 // access control entries. The method take an array of ace_data structures
1045 // that indicate the ACE to be added to the security descriptor.
1046 //
1047 // the caller must free the resources associated with the security
1048 // attributes structure created by this method by calling the
1049 // free_security_attr() method.
1050 //
make_security_attr(ace_data_t aces[],int count)1051 static LPSECURITY_ATTRIBUTES make_security_attr(ace_data_t aces[], int count) {
1052
1053 // allocate space for a security descriptor
1054 PSECURITY_DESCRIPTOR pSD = (PSECURITY_DESCRIPTOR)
1055 NEW_C_HEAP_ARRAY(char, SECURITY_DESCRIPTOR_MIN_LENGTH, mtInternal);
1056
1057 // initialize the security descriptor
1058 if (!InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION)) {
1059 if (PrintMiscellaneous && Verbose) {
1060 warning("InitializeSecurityDescriptor failure: "
1061 "lasterror = %d \n", GetLastError());
1062 }
1063 free_security_desc(pSD);
1064 return NULL;
1065 }
1066
1067 // add the access control entries
1068 if (!add_allow_aces(pSD, aces, count)) {
1069 free_security_desc(pSD);
1070 return NULL;
1071 }
1072
1073 // allocate and initialize the security attributes structure and
1074 // return it to the caller.
1075 //
1076 LPSECURITY_ATTRIBUTES lpSA = (LPSECURITY_ATTRIBUTES)
1077 NEW_C_HEAP_ARRAY(char, sizeof(SECURITY_ATTRIBUTES), mtInternal);
1078 lpSA->nLength = sizeof(SECURITY_ATTRIBUTES);
1079 lpSA->lpSecurityDescriptor = pSD;
1080 lpSA->bInheritHandle = FALSE;
1081
1082 return(lpSA);
1083 }
1084
1085 // method to create a security attributes structure with a restrictive
1086 // access control list that creates a set access rights for the user/owner
1087 // of the securable object and a separate set access rights for everyone else.
1088 // also provides for full access rights for the administrator group.
1089 //
1090 // the caller must free the resources associated with the security
1091 // attributes structure created by this method by calling the
1092 // free_security_attr() method.
1093 //
1094
make_user_everybody_admin_security_attr(DWORD umask,DWORD emask,DWORD amask)1095 static LPSECURITY_ATTRIBUTES make_user_everybody_admin_security_attr(
1096 DWORD umask, DWORD emask, DWORD amask) {
1097
1098 ace_data_t aces[3];
1099
1100 // initialize the user ace data
1101 aces[0].pSid = get_user_sid(GetCurrentProcess());
1102 aces[0].mask = umask;
1103
1104 if (aces[0].pSid == 0)
1105 return NULL;
1106
1107 // get the well known SID for BUILTIN\Administrators
1108 PSID administratorsSid = NULL;
1109 SID_IDENTIFIER_AUTHORITY SIDAuthAdministrators = SECURITY_NT_AUTHORITY;
1110
1111 if (!AllocateAndInitializeSid( &SIDAuthAdministrators, 2,
1112 SECURITY_BUILTIN_DOMAIN_RID,
1113 DOMAIN_ALIAS_RID_ADMINS,
1114 0, 0, 0, 0, 0, 0, &administratorsSid)) {
1115
1116 if (PrintMiscellaneous && Verbose) {
1117 warning("AllocateAndInitializeSid failure: "
1118 "lasterror = %d \n", GetLastError());
1119 }
1120 return NULL;
1121 }
1122
1123 // initialize the ace data for administrator group
1124 aces[1].pSid = administratorsSid;
1125 aces[1].mask = amask;
1126
1127 // get the well known SID for the universal Everybody
1128 PSID everybodySid = NULL;
1129 SID_IDENTIFIER_AUTHORITY SIDAuthEverybody = SECURITY_WORLD_SID_AUTHORITY;
1130
1131 if (!AllocateAndInitializeSid( &SIDAuthEverybody, 1, SECURITY_WORLD_RID,
1132 0, 0, 0, 0, 0, 0, 0, &everybodySid)) {
1133
1134 if (PrintMiscellaneous && Verbose) {
1135 warning("AllocateAndInitializeSid failure: "
1136 "lasterror = %d \n", GetLastError());
1137 }
1138 return NULL;
1139 }
1140
1141 // initialize the ace data for everybody else.
1142 aces[2].pSid = everybodySid;
1143 aces[2].mask = emask;
1144
1145 // create a security attributes structure with access control
1146 // entries as initialized above.
1147 LPSECURITY_ATTRIBUTES lpSA = make_security_attr(aces, 3);
1148 FREE_C_HEAP_ARRAY(char, aces[0].pSid);
1149 FreeSid(everybodySid);
1150 FreeSid(administratorsSid);
1151 return(lpSA);
1152 }
1153
1154
1155 // method to create the security attributes structure for restricting
1156 // access to the user temporary directory.
1157 //
1158 // the caller must free the resources associated with the security
1159 // attributes structure created by this method by calling the
1160 // free_security_attr() method.
1161 //
make_tmpdir_security_attr()1162 static LPSECURITY_ATTRIBUTES make_tmpdir_security_attr() {
1163
1164 // create full access rights for the user/owner of the directory
1165 // and read-only access rights for everybody else. This is
1166 // effectively equivalent to UNIX 755 permissions on a directory.
1167 //
1168 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_ALL_ACCESS;
1169 DWORD emask = GENERIC_READ | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1170 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1171
1172 return make_user_everybody_admin_security_attr(umask, emask, amask);
1173 }
1174
1175 // method to create the security attributes structure for restricting
1176 // access to the shared memory backing store file.
1177 //
1178 // the caller must free the resources associated with the security
1179 // attributes structure created by this method by calling the
1180 // free_security_attr() method.
1181 //
make_file_security_attr()1182 static LPSECURITY_ATTRIBUTES make_file_security_attr() {
1183
1184 // create extensive access rights for the user/owner of the file
1185 // and attribute read-only access rights for everybody else. This
1186 // is effectively equivalent to UNIX 600 permissions on a file.
1187 //
1188 DWORD umask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1189 DWORD emask = STANDARD_RIGHTS_READ | FILE_READ_ATTRIBUTES |
1190 FILE_READ_EA | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1191 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1192
1193 return make_user_everybody_admin_security_attr(umask, emask, amask);
1194 }
1195
1196 // method to create the security attributes structure for restricting
1197 // access to the name shared memory file mapping object.
1198 //
1199 // the caller must free the resources associated with the security
1200 // attributes structure created by this method by calling the
1201 // free_security_attr() method.
1202 //
make_smo_security_attr()1203 static LPSECURITY_ATTRIBUTES make_smo_security_attr() {
1204
1205 // create extensive access rights for the user/owner of the shared
1206 // memory object and attribute read-only access rights for everybody
1207 // else. This is effectively equivalent to UNIX 600 permissions on
1208 // on the shared memory object.
1209 //
1210 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_MAP_ALL_ACCESS;
1211 DWORD emask = STANDARD_RIGHTS_READ; // attributes only
1212 DWORD amask = STANDARD_RIGHTS_ALL | FILE_MAP_ALL_ACCESS;
1213
1214 return make_user_everybody_admin_security_attr(umask, emask, amask);
1215 }
1216
1217 // make the user specific temporary directory
1218 //
make_user_tmp_dir(const char * dirname)1219 static bool make_user_tmp_dir(const char* dirname) {
1220
1221
1222 LPSECURITY_ATTRIBUTES pDirSA = make_tmpdir_security_attr();
1223 if (pDirSA == NULL) {
1224 return false;
1225 }
1226
1227
1228 // create the directory with the given security attributes
1229 if (!CreateDirectory(dirname, pDirSA)) {
1230 DWORD lasterror = GetLastError();
1231 if (lasterror == ERROR_ALREADY_EXISTS) {
1232 // The directory already exists and was probably created by another
1233 // JVM instance. However, this could also be the result of a
1234 // deliberate symlink. Verify that the existing directory is safe.
1235 //
1236 if (!is_directory_secure(dirname)) {
1237 // directory is not secure
1238 if (PrintMiscellaneous && Verbose) {
1239 warning("%s directory is insecure\n", dirname);
1240 }
1241 return false;
1242 }
1243 // The administrator should be able to delete this directory.
1244 // But the directory created by previous version of JVM may not
1245 // have permission for administrators to delete this directory.
1246 // So add full permission to the administrator. Also setting new
1247 // DACLs might fix the corrupted the DACLs.
1248 SECURITY_INFORMATION secInfo = DACL_SECURITY_INFORMATION;
1249 if (!SetFileSecurity(dirname, secInfo, pDirSA->lpSecurityDescriptor)) {
1250 if (PrintMiscellaneous && Verbose) {
1251 lasterror = GetLastError();
1252 warning("SetFileSecurity failed for %s directory. lasterror %d \n",
1253 dirname, lasterror);
1254 }
1255 }
1256 }
1257 else {
1258 if (PrintMiscellaneous && Verbose) {
1259 warning("CreateDirectory failed: %d\n", GetLastError());
1260 }
1261 return false;
1262 }
1263 }
1264
1265 // free the security attributes structure
1266 free_security_attr(pDirSA);
1267
1268 return true;
1269 }
1270
1271 // create the shared memory resources
1272 //
1273 // This function creates the shared memory resources. This includes
1274 // the backing store file and the file mapping shared memory object.
1275 //
create_sharedmem_resources(const char * dirname,const char * filename,const char * objectname,size_t size)1276 static HANDLE create_sharedmem_resources(const char* dirname, const char* filename, const char* objectname, size_t size) {
1277
1278 HANDLE fh = INVALID_HANDLE_VALUE;
1279 HANDLE fmh = NULL;
1280
1281
1282 // create the security attributes for the backing store file
1283 LPSECURITY_ATTRIBUTES lpFileSA = make_file_security_attr();
1284 if (lpFileSA == NULL) {
1285 return NULL;
1286 }
1287
1288 // create the security attributes for the shared memory object
1289 LPSECURITY_ATTRIBUTES lpSmoSA = make_smo_security_attr();
1290 if (lpSmoSA == NULL) {
1291 free_security_attr(lpFileSA);
1292 return NULL;
1293 }
1294
1295 // create the user temporary directory
1296 if (!make_user_tmp_dir(dirname)) {
1297 // could not make/find the directory or the found directory
1298 // was not secure
1299 return NULL;
1300 }
1301
1302 // Create the file - the FILE_FLAG_DELETE_ON_CLOSE flag allows the
1303 // file to be deleted by the last process that closes its handle to
1304 // the file. This is important as the apis do not allow a terminating
1305 // JVM being monitored by another process to remove the file name.
1306 //
1307 fh = CreateFile(
1308 filename, /* LPCTSTR file name */
1309
1310 GENERIC_READ|GENERIC_WRITE, /* DWORD desired access */
1311 FILE_SHARE_DELETE|FILE_SHARE_READ, /* DWORD share mode, future READONLY
1312 * open operations allowed
1313 */
1314 lpFileSA, /* LPSECURITY security attributes */
1315 CREATE_ALWAYS, /* DWORD creation disposition
1316 * create file, if it already
1317 * exists, overwrite it.
1318 */
1319 FILE_FLAG_DELETE_ON_CLOSE, /* DWORD flags and attributes */
1320
1321 NULL); /* HANDLE template file access */
1322
1323 free_security_attr(lpFileSA);
1324
1325 if (fh == INVALID_HANDLE_VALUE) {
1326 DWORD lasterror = GetLastError();
1327 if (PrintMiscellaneous && Verbose) {
1328 warning("could not create file %s: %d\n", filename, lasterror);
1329 }
1330 return NULL;
1331 }
1332
1333 // try to create the file mapping
1334 fmh = create_file_mapping(objectname, fh, lpSmoSA, size);
1335
1336 free_security_attr(lpSmoSA);
1337
1338 if (fmh == NULL) {
1339 // closing the file handle here will decrement the reference count
1340 // on the file. When all processes accessing the file close their
1341 // handle to it, the reference count will decrement to 0 and the
1342 // OS will delete the file. These semantics are requested by the
1343 // FILE_FLAG_DELETE_ON_CLOSE flag in CreateFile call above.
1344 CloseHandle(fh);
1345 fh = NULL;
1346 return NULL;
1347 } else {
1348 // We created the file mapping, but rarely the size of the
1349 // backing store file is reported as zero (0) which can cause
1350 // failures when trying to use the hsperfdata file.
1351 struct stat statbuf;
1352 int ret_code = ::stat(filename, &statbuf);
1353 if (ret_code == OS_ERR) {
1354 if (PrintMiscellaneous && Verbose) {
1355 warning("Could not get status information from file %s: %s\n",
1356 filename, os::strerror(errno));
1357 }
1358 CloseHandle(fmh);
1359 CloseHandle(fh);
1360 fh = NULL;
1361 fmh = NULL;
1362 return NULL;
1363 }
1364
1365 // We could always call FlushFileBuffers() but the Microsoft
1366 // docs indicate that it is considered expensive so we only
1367 // call it when we observe the size as zero (0).
1368 if (statbuf.st_size == 0 && FlushFileBuffers(fh) != TRUE) {
1369 DWORD lasterror = GetLastError();
1370 if (PrintMiscellaneous && Verbose) {
1371 warning("could not flush file %s: %d\n", filename, lasterror);
1372 }
1373 CloseHandle(fmh);
1374 CloseHandle(fh);
1375 fh = NULL;
1376 fmh = NULL;
1377 return NULL;
1378 }
1379 }
1380
1381 // the file has been successfully created and the file mapping
1382 // object has been created.
1383 sharedmem_fileHandle = fh;
1384 sharedmem_fileName = os::strdup(filename);
1385
1386 return fmh;
1387 }
1388
1389 // open the shared memory object for the given vmid.
1390 //
open_sharedmem_object(const char * objectname,DWORD ofm_access,TRAPS)1391 static HANDLE open_sharedmem_object(const char* objectname, DWORD ofm_access, TRAPS) {
1392
1393 HANDLE fmh;
1394
1395 // open the file mapping with the requested mode
1396 fmh = OpenFileMapping(
1397 ofm_access, /* DWORD access mode */
1398 FALSE, /* BOOL inherit flag - Do not allow inherit */
1399 objectname); /* name for object */
1400
1401 if (fmh == NULL) {
1402 DWORD lasterror = GetLastError();
1403 if (PrintMiscellaneous && Verbose) {
1404 warning("OpenFileMapping failed for shared memory object %s:"
1405 " lasterror = %d\n", objectname, lasterror);
1406 }
1407 THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
1408 err_msg("Could not open PerfMemory, error %d", lasterror),
1409 INVALID_HANDLE_VALUE);
1410 }
1411
1412 return fmh;;
1413 }
1414
1415 // create a named shared memory region
1416 //
1417 // On Win32, a named shared memory object has a name space that
1418 // is independent of the file system name space. Shared memory object,
1419 // or more precisely, file mapping objects, provide no mechanism to
1420 // inquire the size of the memory region. There is also no api to
1421 // enumerate the memory regions for various processes.
1422 //
1423 // This implementation utilizes the shared memory name space in parallel
1424 // with the file system name space. This allows us to determine the
1425 // size of the shared memory region from the size of the file and it
1426 // allows us to provide a common, file system based name space for
1427 // shared memory across platforms.
1428 //
mapping_create_shared(size_t size)1429 static char* mapping_create_shared(size_t size) {
1430
1431 void *mapAddress;
1432 int vmid = os::current_process_id();
1433
1434 // get the name of the user associated with this process
1435 char* user = get_user_name();
1436
1437 if (user == NULL) {
1438 return NULL;
1439 }
1440
1441 // construct the name of the user specific temporary directory
1442 char* dirname = get_user_tmp_dir(user);
1443
1444 // check that the file system is secure - i.e. it supports ACLs.
1445 if (!is_filesystem_secure(dirname)) {
1446 FREE_C_HEAP_ARRAY(char, dirname);
1447 FREE_C_HEAP_ARRAY(char, user);
1448 return NULL;
1449 }
1450
1451 // create the names of the backing store files and for the
1452 // share memory object.
1453 //
1454 char* filename = get_sharedmem_filename(dirname, vmid);
1455 char* objectname = get_sharedmem_objectname(user, vmid);
1456
1457 // cleanup any stale shared memory resources
1458 cleanup_sharedmem_resources(dirname);
1459
1460 assert(((size != 0) && (size % os::vm_page_size() == 0)),
1461 "unexpected PerfMemry region size");
1462
1463 FREE_C_HEAP_ARRAY(char, user);
1464
1465 // create the shared memory resources
1466 sharedmem_fileMapHandle =
1467 create_sharedmem_resources(dirname, filename, objectname, size);
1468
1469 FREE_C_HEAP_ARRAY(char, filename);
1470 FREE_C_HEAP_ARRAY(char, objectname);
1471 FREE_C_HEAP_ARRAY(char, dirname);
1472
1473 if (sharedmem_fileMapHandle == NULL) {
1474 return NULL;
1475 }
1476
1477 // map the file into the address space
1478 mapAddress = MapViewOfFile(
1479 sharedmem_fileMapHandle, /* HANDLE = file mapping object */
1480 FILE_MAP_ALL_ACCESS, /* DWORD access flags */
1481 0, /* DWORD High word of offset */
1482 0, /* DWORD Low word of offset */
1483 (DWORD)size); /* DWORD Number of bytes to map */
1484
1485 if (mapAddress == NULL) {
1486 if (PrintMiscellaneous && Verbose) {
1487 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1488 }
1489 CloseHandle(sharedmem_fileMapHandle);
1490 sharedmem_fileMapHandle = NULL;
1491 return NULL;
1492 }
1493
1494 // clear the shared memory region
1495 (void)memset(mapAddress, '\0', size);
1496
1497 // it does not go through os api, the operation has to record from here
1498 MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress,
1499 size, CURRENT_PC, mtInternal);
1500
1501 return (char*) mapAddress;
1502 }
1503
1504 // this method deletes the file mapping object.
1505 //
delete_file_mapping(char * addr,size_t size)1506 static void delete_file_mapping(char* addr, size_t size) {
1507
1508 // cleanup the persistent shared memory resources. since DestroyJavaVM does
1509 // not support unloading of the JVM, unmapping of the memory resource is not
1510 // performed. The memory will be reclaimed by the OS upon termination of all
1511 // processes mapping the resource. The file mapping handle and the file
1512 // handle are closed here to expedite the remove of the file by the OS. The
1513 // file is not removed directly because it was created with
1514 // FILE_FLAG_DELETE_ON_CLOSE semantics and any attempt to remove it would
1515 // be unsuccessful.
1516
1517 // close the fileMapHandle. the file mapping will still be retained
1518 // by the OS as long as any other JVM processes has an open file mapping
1519 // handle or a mapped view of the file.
1520 //
1521 if (sharedmem_fileMapHandle != NULL) {
1522 CloseHandle(sharedmem_fileMapHandle);
1523 sharedmem_fileMapHandle = NULL;
1524 }
1525
1526 // close the file handle. This will decrement the reference count on the
1527 // backing store file. When the reference count decrements to 0, the OS
1528 // will delete the file. These semantics apply because the file was
1529 // created with the FILE_FLAG_DELETE_ON_CLOSE flag.
1530 //
1531 if (sharedmem_fileHandle != INVALID_HANDLE_VALUE) {
1532 CloseHandle(sharedmem_fileHandle);
1533 sharedmem_fileHandle = INVALID_HANDLE_VALUE;
1534 }
1535 }
1536
1537 // this method determines the size of the shared memory file
1538 //
sharedmem_filesize(const char * filename,TRAPS)1539 static size_t sharedmem_filesize(const char* filename, TRAPS) {
1540
1541 struct stat statbuf;
1542
1543 // get the file size
1544 //
1545 // on win95/98/me, _stat returns a file size of 0 bytes, but on
1546 // winnt/2k the appropriate file size is returned. support for
1547 // the sharable aspects of performance counters was abandonded
1548 // on the non-nt win32 platforms due to this and other api
1549 // inconsistencies
1550 //
1551 if (::stat(filename, &statbuf) == OS_ERR) {
1552 if (PrintMiscellaneous && Verbose) {
1553 warning("stat %s failed: %s\n", filename, os::strerror(errno));
1554 }
1555 THROW_MSG_0(vmSymbols::java_io_IOException(),
1556 "Could not determine PerfMemory size");
1557 }
1558
1559 if ((statbuf.st_size == 0) || (statbuf.st_size % os::vm_page_size() != 0)) {
1560 if (PrintMiscellaneous && Verbose) {
1561 warning("unexpected file size: size = " SIZE_FORMAT "\n",
1562 statbuf.st_size);
1563 }
1564 THROW_MSG_0(vmSymbols::java_lang_Exception(),
1565 "Invalid PerfMemory size");
1566 }
1567
1568 return statbuf.st_size;
1569 }
1570
1571 // this method opens a file mapping object and maps the object
1572 // into the address space of the process
1573 //
open_file_mapping(const char * user,int vmid,PerfMemory::PerfMemoryMode mode,char ** addrp,size_t * sizep,TRAPS)1574 static void open_file_mapping(const char* user, int vmid,
1575 PerfMemory::PerfMemoryMode mode,
1576 char** addrp, size_t* sizep, TRAPS) {
1577
1578 ResourceMark rm;
1579
1580 void *mapAddress = 0;
1581 size_t size = 0;
1582 HANDLE fmh;
1583 DWORD ofm_access;
1584 DWORD mv_access;
1585 const char* luser = NULL;
1586
1587 if (mode == PerfMemory::PERF_MODE_RO) {
1588 ofm_access = FILE_MAP_READ;
1589 mv_access = FILE_MAP_READ;
1590 }
1591 else if (mode == PerfMemory::PERF_MODE_RW) {
1592 #ifdef LATER
1593 ofm_access = FILE_MAP_READ | FILE_MAP_WRITE;
1594 mv_access = FILE_MAP_READ | FILE_MAP_WRITE;
1595 #else
1596 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1597 "Unsupported access mode");
1598 #endif
1599 }
1600 else {
1601 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1602 "Illegal access mode");
1603 }
1604
1605 // if a user name wasn't specified, then find the user name for
1606 // the owner of the target vm.
1607 if (user == NULL || strlen(user) == 0) {
1608 luser = get_user_name(vmid);
1609 }
1610 else {
1611 luser = user;
1612 }
1613
1614 if (luser == NULL) {
1615 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1616 "Could not map vmid to user name");
1617 }
1618
1619 // get the names for the resources for the target vm
1620 char* dirname = get_user_tmp_dir(luser);
1621
1622 // since we don't follow symbolic links when creating the backing
1623 // store file, we also don't following them when attaching
1624 //
1625 if (!is_directory_secure(dirname)) {
1626 FREE_C_HEAP_ARRAY(char, dirname);
1627 if (luser != user) FREE_C_HEAP_ARRAY(char, luser);
1628 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1629 "Process not found");
1630 }
1631
1632 char* filename = get_sharedmem_filename(dirname, vmid);
1633 char* objectname = get_sharedmem_objectname(luser, vmid);
1634
1635 // copy heap memory to resource memory. the objectname and
1636 // filename are passed to methods that may throw exceptions.
1637 // using resource arrays for these names prevents the leaks
1638 // that would otherwise occur.
1639 //
1640 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
1641 char* robjectname = NEW_RESOURCE_ARRAY(char, strlen(objectname) + 1);
1642 strcpy(rfilename, filename);
1643 strcpy(robjectname, objectname);
1644
1645 // free the c heap resources that are no longer needed
1646 if (luser != user) FREE_C_HEAP_ARRAY(char, luser);
1647 FREE_C_HEAP_ARRAY(char, dirname);
1648 FREE_C_HEAP_ARRAY(char, filename);
1649 FREE_C_HEAP_ARRAY(char, objectname);
1650
1651 if (*sizep == 0) {
1652 size = sharedmem_filesize(rfilename, CHECK);
1653 } else {
1654 size = *sizep;
1655 }
1656
1657 assert(size > 0, "unexpected size <= 0");
1658
1659 // Open the file mapping object with the given name
1660 fmh = open_sharedmem_object(robjectname, ofm_access, CHECK);
1661
1662 assert(fmh != INVALID_HANDLE_VALUE, "unexpected handle value");
1663
1664 // map the entire file into the address space
1665 mapAddress = MapViewOfFile(
1666 fmh, /* HANDLE Handle of file mapping object */
1667 mv_access, /* DWORD access flags */
1668 0, /* DWORD High word of offset */
1669 0, /* DWORD Low word of offset */
1670 size); /* DWORD Number of bytes to map */
1671
1672 if (mapAddress == NULL) {
1673 if (PrintMiscellaneous && Verbose) {
1674 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1675 }
1676 CloseHandle(fmh);
1677 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
1678 "Could not map PerfMemory");
1679 }
1680
1681 // it does not go through os api, the operation has to record from here
1682 MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress, size,
1683 CURRENT_PC, mtInternal);
1684
1685
1686 *addrp = (char*)mapAddress;
1687 *sizep = size;
1688
1689 // File mapping object can be closed at this time without
1690 // invalidating the mapped view of the file
1691 CloseHandle(fmh);
1692
1693 log_debug(perf, memops)("mapped " SIZE_FORMAT " bytes for vmid %d at "
1694 INTPTR_FORMAT, size, vmid, mapAddress);
1695 }
1696
1697 // this method unmaps the the mapped view of the the
1698 // file mapping object.
1699 //
remove_file_mapping(char * addr)1700 static void remove_file_mapping(char* addr) {
1701
1702 // the file mapping object was closed in open_file_mapping()
1703 // after the file map view was created. We only need to
1704 // unmap the file view here.
1705 UnmapViewOfFile(addr);
1706 }
1707
1708 // create the PerfData memory region in shared memory.
create_shared_memory(size_t size)1709 static char* create_shared_memory(size_t size) {
1710
1711 return mapping_create_shared(size);
1712 }
1713
1714 // release a named, shared memory region
1715 //
delete_shared_memory(char * addr,size_t size)1716 void delete_shared_memory(char* addr, size_t size) {
1717
1718 delete_file_mapping(addr, size);
1719 }
1720
1721
1722
1723
1724 // create the PerfData memory region
1725 //
1726 // This method creates the memory region used to store performance
1727 // data for the JVM. The memory may be created in standard or
1728 // shared memory.
1729 //
create_memory_region(size_t size)1730 void PerfMemory::create_memory_region(size_t size) {
1731
1732 if (PerfDisableSharedMem) {
1733 // do not share the memory for the performance data.
1734 PerfDisableSharedMem = true;
1735 _start = create_standard_memory(size);
1736 }
1737 else {
1738 _start = create_shared_memory(size);
1739 if (_start == NULL) {
1740
1741 // creation of the shared memory region failed, attempt
1742 // to create a contiguous, non-shared memory region instead.
1743 //
1744 if (PrintMiscellaneous && Verbose) {
1745 warning("Reverting to non-shared PerfMemory region.\n");
1746 }
1747 PerfDisableSharedMem = true;
1748 _start = create_standard_memory(size);
1749 }
1750 }
1751
1752 if (_start != NULL) _capacity = size;
1753
1754 }
1755
1756 // delete the PerfData memory region
1757 //
1758 // This method deletes the memory region used to store performance
1759 // data for the JVM. The memory region indicated by the <address, size>
1760 // tuple will be inaccessible after a call to this method.
1761 //
delete_memory_region()1762 void PerfMemory::delete_memory_region() {
1763
1764 assert((start() != NULL && capacity() > 0), "verify proper state");
1765
1766 // If user specifies PerfDataSaveFile, it will save the performance data
1767 // to the specified file name no matter whether PerfDataSaveToFile is specified
1768 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
1769 // -XX:+PerfDataSaveToFile.
1770 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
1771 save_memory_to_file(start(), capacity());
1772 }
1773
1774 if (PerfDisableSharedMem) {
1775 delete_standard_memory(start(), capacity());
1776 }
1777 else {
1778 delete_shared_memory(start(), capacity());
1779 }
1780 }
1781
1782 // attach to the PerfData memory region for another JVM
1783 //
1784 // This method returns an <address, size> tuple that points to
1785 // a memory buffer that is kept reasonably synchronized with
1786 // the PerfData memory region for the indicated JVM. This
1787 // buffer may be kept in synchronization via shared memory
1788 // or some other mechanism that keeps the buffer updated.
1789 //
1790 // If the JVM chooses not to support the attachability feature,
1791 // this method should throw an UnsupportedOperation exception.
1792 //
1793 // This implementation utilizes named shared memory to map
1794 // the indicated process's PerfData memory region into this JVMs
1795 // address space.
1796 //
attach(const char * user,int vmid,PerfMemoryMode mode,char ** addrp,size_t * sizep,TRAPS)1797 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode,
1798 char** addrp, size_t* sizep, TRAPS) {
1799
1800 if (vmid == 0 || vmid == os::current_process_id()) {
1801 *addrp = start();
1802 *sizep = capacity();
1803 return;
1804 }
1805
1806 open_file_mapping(user, vmid, mode, addrp, sizep, CHECK);
1807 }
1808
1809 // detach from the PerfData memory region of another JVM
1810 //
1811 // This method detaches the PerfData memory region of another
1812 // JVM, specified as an <address, size> tuple of a buffer
1813 // in this process's address space. This method may perform
1814 // arbitrary actions to accomplish the detachment. The memory
1815 // region specified by <address, size> will be inaccessible after
1816 // a call to this method.
1817 //
1818 // If the JVM chooses not to support the attachability feature,
1819 // this method should throw an UnsupportedOperation exception.
1820 //
1821 // This implementation utilizes named shared memory to detach
1822 // the indicated process's PerfData memory region from this
1823 // process's address space.
1824 //
detach(char * addr,size_t bytes,TRAPS)1825 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
1826
1827 assert(addr != 0, "address sanity check");
1828 assert(bytes > 0, "capacity sanity check");
1829
1830 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
1831 // prevent accidental detachment of this process's PerfMemory region
1832 return;
1833 }
1834
1835 if (MemTracker::tracking_level() > NMT_minimal) {
1836 // it does not go through os api, the operation has to record from here
1837 Tracker tkr(Tracker::release);
1838 remove_file_mapping(addr);
1839 tkr.record((address)addr, bytes);
1840 } else {
1841 remove_file_mapping(addr);
1842 }
1843 }
1844