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annotate src/os/windows/vm/perfMemory_windows.cpp @ 1968:0b33f0736406
6837842: JNI_CreateJavaVM crashes under impersonation
Reviewed-by: acorn, dholmes
author | poonam |
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date | Fri, 19 Nov 2010 03:41:50 -0800 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 2001, 2007, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_perfMemory_windows.cpp.incl" | |
27 | |
28 #include <windows.h> | |
29 #include <sys/types.h> | |
30 #include <sys/stat.h> | |
31 #include <errno.h> | |
32 #include <lmcons.h> | |
33 | |
34 typedef BOOL (WINAPI *SetSecurityDescriptorControlFnPtr)( | |
35 IN PSECURITY_DESCRIPTOR pSecurityDescriptor, | |
36 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsOfInterest, | |
37 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsToSet); | |
38 | |
39 // Standard Memory Implementation Details | |
40 | |
41 // create the PerfData memory region in standard memory. | |
42 // | |
43 static char* create_standard_memory(size_t size) { | |
44 | |
45 // allocate an aligned chuck of memory | |
46 char* mapAddress = os::reserve_memory(size); | |
47 | |
48 if (mapAddress == NULL) { | |
49 return NULL; | |
50 } | |
51 | |
52 // commit memory | |
53 if (!os::commit_memory(mapAddress, size)) { | |
54 if (PrintMiscellaneous && Verbose) { | |
55 warning("Could not commit PerfData memory\n"); | |
56 } | |
57 os::release_memory(mapAddress, size); | |
58 return NULL; | |
59 } | |
60 | |
61 return mapAddress; | |
62 } | |
63 | |
64 // delete the PerfData memory region | |
65 // | |
66 static void delete_standard_memory(char* addr, size_t size) { | |
67 | |
68 // there are no persistent external resources to cleanup for standard | |
69 // memory. since DestroyJavaVM does not support unloading of the JVM, | |
70 // cleanup of the memory resource is not performed. The memory will be | |
71 // reclaimed by the OS upon termination of the process. | |
72 // | |
73 return; | |
74 | |
75 } | |
76 | |
77 // save the specified memory region to the given file | |
78 // | |
79 static void save_memory_to_file(char* addr, size_t size) { | |
80 | |
81 const char* destfile = PerfMemory::get_perfdata_file_path(); | |
82 assert(destfile[0] != '\0', "invalid Perfdata file path"); | |
83 | |
84 int fd = ::_open(destfile, _O_BINARY|_O_CREAT|_O_WRONLY|_O_TRUNC, | |
85 _S_IREAD|_S_IWRITE); | |
86 | |
87 if (fd == OS_ERR) { | |
88 if (PrintMiscellaneous && Verbose) { | |
89 warning("Could not create Perfdata save file: %s: %s\n", | |
90 destfile, strerror(errno)); | |
91 } | |
92 } else { | |
93 for (size_t remaining = size; remaining > 0;) { | |
94 | |
95 int nbytes = ::_write(fd, addr, (unsigned int)remaining); | |
96 if (nbytes == OS_ERR) { | |
97 if (PrintMiscellaneous && Verbose) { | |
98 warning("Could not write Perfdata save file: %s: %s\n", | |
99 destfile, strerror(errno)); | |
100 } | |
101 break; | |
102 } | |
103 | |
104 remaining -= (size_t)nbytes; | |
105 addr += nbytes; | |
106 } | |
107 | |
108 int result = ::_close(fd); | |
109 if (PrintMiscellaneous && Verbose) { | |
110 if (result == OS_ERR) { | |
111 warning("Could not close %s: %s\n", destfile, strerror(errno)); | |
112 } | |
113 } | |
114 } | |
115 | |
116 FREE_C_HEAP_ARRAY(char, destfile); | |
117 } | |
118 | |
119 // Shared Memory Implementation Details | |
120 | |
121 // Note: the win32 shared memory implementation uses two objects to represent | |
122 // the shared memory: a windows kernel based file mapping object and a backing | |
123 // store file. On windows, the name space for shared memory is a kernel | |
124 // based name space that is disjoint from other win32 name spaces. Since Java | |
125 // is unaware of this name space, a parallel file system based name space is | |
126 // maintained, which provides a common file system based shared memory name | |
127 // space across the supported platforms and one that Java apps can deal with | |
128 // through simple file apis. | |
129 // | |
130 // For performance and resource cleanup reasons, it is recommended that the | |
131 // user specific directory and the backing store file be stored in either a | |
132 // RAM based file system or a local disk based file system. Network based | |
133 // file systems are not recommended for performance reasons. In addition, | |
134 // use of SMB network based file systems may result in unsuccesful cleanup | |
135 // of the disk based resource on exit of the VM. The Windows TMP and TEMP | |
136 // environement variables, as used by the GetTempPath() Win32 API (see | |
137 // os::get_temp_directory() in os_win32.cpp), control the location of the | |
138 // user specific directory and the shared memory backing store file. | |
139 | |
140 static HANDLE sharedmem_fileMapHandle = NULL; | |
141 static HANDLE sharedmem_fileHandle = INVALID_HANDLE_VALUE; | |
142 static char* sharedmem_fileName = NULL; | |
143 | |
144 // return the user specific temporary directory name. | |
145 // | |
146 // the caller is expected to free the allocated memory. | |
147 // | |
148 static char* get_user_tmp_dir(const char* user) { | |
149 | |
150 const char* tmpdir = os::get_temp_directory(); | |
151 const char* perfdir = PERFDATA_NAME; | |
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152 size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3; |
0 | 153 char* dirname = NEW_C_HEAP_ARRAY(char, nbytes); |
154 | |
155 // construct the path name to user specific tmp directory | |
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156 _snprintf(dirname, nbytes, "%s\\%s_%s", tmpdir, perfdir, user); |
0 | 157 |
158 return dirname; | |
159 } | |
160 | |
161 // convert the given file name into a process id. if the file | |
162 // does not meet the file naming constraints, return 0. | |
163 // | |
164 static int filename_to_pid(const char* filename) { | |
165 | |
166 // a filename that doesn't begin with a digit is not a | |
167 // candidate for conversion. | |
168 // | |
169 if (!isdigit(*filename)) { | |
170 return 0; | |
171 } | |
172 | |
173 // check if file name can be converted to an integer without | |
174 // any leftover characters. | |
175 // | |
176 char* remainder = NULL; | |
177 errno = 0; | |
178 int pid = (int)strtol(filename, &remainder, 10); | |
179 | |
180 if (errno != 0) { | |
181 return 0; | |
182 } | |
183 | |
184 // check for left over characters. If any, then the filename is | |
185 // not a candidate for conversion. | |
186 // | |
187 if (remainder != NULL && *remainder != '\0') { | |
188 return 0; | |
189 } | |
190 | |
191 // successful conversion, return the pid | |
192 return pid; | |
193 } | |
194 | |
195 // check if the given path is considered a secure directory for | |
196 // the backing store files. Returns true if the directory exists | |
197 // and is considered a secure location. Returns false if the path | |
605 | 198 // is a symbolic link or if an error occurred. |
0 | 199 // |
200 static bool is_directory_secure(const char* path) { | |
201 | |
202 DWORD fa; | |
203 | |
204 fa = GetFileAttributes(path); | |
205 if (fa == 0xFFFFFFFF) { | |
206 DWORD lasterror = GetLastError(); | |
207 if (lasterror == ERROR_FILE_NOT_FOUND) { | |
208 return false; | |
209 } | |
210 else { | |
211 // unexpected error, declare the path insecure | |
212 if (PrintMiscellaneous && Verbose) { | |
213 warning("could not get attributes for file %s: ", | |
214 " lasterror = %d\n", path, lasterror); | |
215 } | |
216 return false; | |
217 } | |
218 } | |
219 | |
220 if (fa & FILE_ATTRIBUTE_REPARSE_POINT) { | |
221 // we don't accept any redirection for the user specific directory | |
222 // so declare the path insecure. This may be too conservative, | |
223 // as some types of reparse points might be acceptable, but it | |
224 // is probably more secure to avoid these conditions. | |
225 // | |
226 if (PrintMiscellaneous && Verbose) { | |
227 warning("%s is a reparse point\n", path); | |
228 } | |
229 return false; | |
230 } | |
231 | |
232 if (fa & FILE_ATTRIBUTE_DIRECTORY) { | |
233 // this is the expected case. Since windows supports symbolic | |
234 // links to directories only, not to files, there is no need | |
235 // to check for open write permissions on the directory. If the | |
236 // directory has open write permissions, any files deposited that | |
237 // are not expected will be removed by the cleanup code. | |
238 // | |
239 return true; | |
240 } | |
241 else { | |
242 // this is either a regular file or some other type of file, | |
243 // any of which are unexpected and therefore insecure. | |
244 // | |
245 if (PrintMiscellaneous && Verbose) { | |
246 warning("%s is not a directory, file attributes = " | |
247 INTPTR_FORMAT "\n", path, fa); | |
248 } | |
249 return false; | |
250 } | |
251 } | |
252 | |
253 // return the user name for the owner of this process | |
254 // | |
255 // the caller is expected to free the allocated memory. | |
256 // | |
257 static char* get_user_name() { | |
258 | |
259 /* get the user name. This code is adapted from code found in | |
260 * the jdk in src/windows/native/java/lang/java_props_md.c | |
261 * java_props_md.c 1.29 02/02/06. According to the original | |
262 * source, the call to GetUserName is avoided because of a resulting | |
263 * increase in footprint of 100K. | |
264 */ | |
265 char* user = getenv("USERNAME"); | |
266 char buf[UNLEN+1]; | |
267 DWORD buflen = sizeof(buf); | |
268 if (user == NULL || strlen(user) == 0) { | |
269 if (GetUserName(buf, &buflen)) { | |
270 user = buf; | |
271 } | |
272 else { | |
273 return NULL; | |
274 } | |
275 } | |
276 | |
277 char* user_name = NEW_C_HEAP_ARRAY(char, strlen(user)+1); | |
278 strcpy(user_name, user); | |
279 | |
280 return user_name; | |
281 } | |
282 | |
283 // return the name of the user that owns the process identified by vmid. | |
284 // | |
285 // This method uses a slow directory search algorithm to find the backing | |
286 // store file for the specified vmid and returns the user name, as determined | |
287 // by the user name suffix of the hsperfdata_<username> directory name. | |
288 // | |
289 // the caller is expected to free the allocated memory. | |
290 // | |
291 static char* get_user_name_slow(int vmid) { | |
292 | |
293 // directory search | |
294 char* oldest_user = NULL; | |
295 time_t oldest_ctime = 0; | |
296 | |
297 const char* tmpdirname = os::get_temp_directory(); | |
298 | |
299 DIR* tmpdirp = os::opendir(tmpdirname); | |
300 | |
301 if (tmpdirp == NULL) { | |
302 return NULL; | |
303 } | |
304 | |
305 // for each entry in the directory that matches the pattern hsperfdata_*, | |
306 // open the directory and check if the file for the given vmid exists. | |
307 // The file with the expected name and the latest creation date is used | |
308 // to determine the user name for the process id. | |
309 // | |
310 struct dirent* dentry; | |
311 char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname)); | |
312 errno = 0; | |
313 while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) { | |
314 | |
315 // check if the directory entry is a hsperfdata file | |
316 if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) { | |
317 continue; | |
318 } | |
319 | |
320 char* usrdir_name = NEW_C_HEAP_ARRAY(char, | |
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321 strlen(tmpdirname) + strlen(dentry->d_name) + 2); |
0 | 322 strcpy(usrdir_name, tmpdirname); |
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323 strcat(usrdir_name, "\\"); |
0 | 324 strcat(usrdir_name, dentry->d_name); |
325 | |
326 DIR* subdirp = os::opendir(usrdir_name); | |
327 | |
328 if (subdirp == NULL) { | |
329 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
330 continue; | |
331 } | |
332 | |
333 // Since we don't create the backing store files in directories | |
334 // pointed to by symbolic links, we also don't follow them when | |
335 // looking for the files. We check for a symbolic link after the | |
336 // call to opendir in order to eliminate a small window where the | |
337 // symlink can be exploited. | |
338 // | |
339 if (!is_directory_secure(usrdir_name)) { | |
340 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
341 os::closedir(subdirp); | |
342 continue; | |
343 } | |
344 | |
345 struct dirent* udentry; | |
346 char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name)); | |
347 errno = 0; | |
348 while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) { | |
349 | |
350 if (filename_to_pid(udentry->d_name) == vmid) { | |
351 struct stat statbuf; | |
352 | |
353 char* filename = NEW_C_HEAP_ARRAY(char, | |
354 strlen(usrdir_name) + strlen(udentry->d_name) + 2); | |
355 | |
356 strcpy(filename, usrdir_name); | |
357 strcat(filename, "\\"); | |
358 strcat(filename, udentry->d_name); | |
359 | |
360 if (::stat(filename, &statbuf) == OS_ERR) { | |
361 FREE_C_HEAP_ARRAY(char, filename); | |
362 continue; | |
363 } | |
364 | |
365 // skip over files that are not regular files. | |
366 if ((statbuf.st_mode & S_IFMT) != S_IFREG) { | |
367 FREE_C_HEAP_ARRAY(char, filename); | |
368 continue; | |
369 } | |
370 | |
371 // compare and save filename with latest creation time | |
372 if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) { | |
373 | |
374 if (statbuf.st_ctime > oldest_ctime) { | |
375 char* user = strchr(dentry->d_name, '_') + 1; | |
376 | |
377 if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user); | |
378 oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1); | |
379 | |
380 strcpy(oldest_user, user); | |
381 oldest_ctime = statbuf.st_ctime; | |
382 } | |
383 } | |
384 | |
385 FREE_C_HEAP_ARRAY(char, filename); | |
386 } | |
387 } | |
388 os::closedir(subdirp); | |
389 FREE_C_HEAP_ARRAY(char, udbuf); | |
390 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
391 } | |
392 os::closedir(tmpdirp); | |
393 FREE_C_HEAP_ARRAY(char, tdbuf); | |
394 | |
395 return(oldest_user); | |
396 } | |
397 | |
398 // return the name of the user that owns the process identified by vmid. | |
399 // | |
400 // note: this method should only be used via the Perf native methods. | |
401 // There are various costs to this method and limiting its use to the | |
402 // Perf native methods limits the impact to monitoring applications only. | |
403 // | |
404 static char* get_user_name(int vmid) { | |
405 | |
406 // A fast implementation is not provided at this time. It's possible | |
407 // to provide a fast process id to user name mapping function using | |
408 // the win32 apis, but the default ACL for the process object only | |
409 // allows processes with the same owner SID to acquire the process | |
410 // handle (via OpenProcess(PROCESS_QUERY_INFORMATION)). It's possible | |
411 // to have the JVM change the ACL for the process object to allow arbitrary | |
412 // users to access the process handle and the process security token. | |
413 // The security ramifications need to be studied before providing this | |
414 // mechanism. | |
415 // | |
416 return get_user_name_slow(vmid); | |
417 } | |
418 | |
419 // return the name of the shared memory file mapping object for the | |
420 // named shared memory region for the given user name and vmid. | |
421 // | |
422 // The file mapping object's name is not the file name. It is a name | |
423 // in a separate name space. | |
424 // | |
425 // the caller is expected to free the allocated memory. | |
426 // | |
427 static char *get_sharedmem_objectname(const char* user, int vmid) { | |
428 | |
429 // construct file mapping object's name, add 3 for two '_' and a | |
430 // null terminator. | |
431 int nbytes = (int)strlen(PERFDATA_NAME) + (int)strlen(user) + 3; | |
432 | |
433 // the id is converted to an unsigned value here because win32 allows | |
434 // negative process ids. However, OpenFileMapping API complains | |
435 // about a name containing a '-' characters. | |
436 // | |
437 nbytes += UINT_CHARS; | |
438 char* name = NEW_C_HEAP_ARRAY(char, nbytes); | |
439 _snprintf(name, nbytes, "%s_%s_%u", PERFDATA_NAME, user, vmid); | |
440 | |
441 return name; | |
442 } | |
443 | |
444 // return the file name of the backing store file for the named | |
445 // shared memory region for the given user name and vmid. | |
446 // | |
447 // the caller is expected to free the allocated memory. | |
448 // | |
449 static char* get_sharedmem_filename(const char* dirname, int vmid) { | |
450 | |
451 // add 2 for the file separator and a null terminator. | |
452 size_t nbytes = strlen(dirname) + UINT_CHARS + 2; | |
453 | |
454 char* name = NEW_C_HEAP_ARRAY(char, nbytes); | |
455 _snprintf(name, nbytes, "%s\\%d", dirname, vmid); | |
456 | |
457 return name; | |
458 } | |
459 | |
460 // remove file | |
461 // | |
462 // this method removes the file with the given file name. | |
463 // | |
464 // Note: if the indicated file is on an SMB network file system, this | |
465 // method may be unsuccessful in removing the file. | |
466 // | |
467 static void remove_file(const char* dirname, const char* filename) { | |
468 | |
469 size_t nbytes = strlen(dirname) + strlen(filename) + 2; | |
470 char* path = NEW_C_HEAP_ARRAY(char, nbytes); | |
471 | |
472 strcpy(path, dirname); | |
473 strcat(path, "\\"); | |
474 strcat(path, filename); | |
475 | |
476 if (::unlink(path) == OS_ERR) { | |
477 if (PrintMiscellaneous && Verbose) { | |
478 if (errno != ENOENT) { | |
479 warning("Could not unlink shared memory backing" | |
480 " store file %s : %s\n", path, strerror(errno)); | |
481 } | |
482 } | |
483 } | |
484 | |
485 FREE_C_HEAP_ARRAY(char, path); | |
486 } | |
487 | |
488 // returns true if the process represented by pid is alive, otherwise | |
489 // returns false. the validity of the result is only accurate if the | |
490 // target process is owned by the same principal that owns this process. | |
491 // this method should not be used if to test the status of an otherwise | |
492 // arbitrary process unless it is know that this process has the appropriate | |
493 // privileges to guarantee a result valid. | |
494 // | |
495 static bool is_alive(int pid) { | |
496 | |
497 HANDLE ph = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid); | |
498 if (ph == NULL) { | |
499 // the process does not exist. | |
500 if (PrintMiscellaneous && Verbose) { | |
501 DWORD lastError = GetLastError(); | |
502 if (lastError != ERROR_INVALID_PARAMETER) { | |
503 warning("OpenProcess failed: %d\n", GetLastError()); | |
504 } | |
505 } | |
506 return false; | |
507 } | |
508 | |
509 DWORD exit_status; | |
510 if (!GetExitCodeProcess(ph, &exit_status)) { | |
511 if (PrintMiscellaneous && Verbose) { | |
512 warning("GetExitCodeProcess failed: %d\n", GetLastError()); | |
513 } | |
514 CloseHandle(ph); | |
515 return false; | |
516 } | |
517 | |
518 CloseHandle(ph); | |
519 return (exit_status == STILL_ACTIVE) ? true : false; | |
520 } | |
521 | |
522 // check if the file system is considered secure for the backing store files | |
523 // | |
524 static bool is_filesystem_secure(const char* path) { | |
525 | |
526 char root_path[MAX_PATH]; | |
527 char fs_type[MAX_PATH]; | |
528 | |
529 if (PerfBypassFileSystemCheck) { | |
530 if (PrintMiscellaneous && Verbose) { | |
531 warning("bypassing file system criteria checks for %s\n", path); | |
532 } | |
533 return true; | |
534 } | |
535 | |
536 char* first_colon = strchr((char *)path, ':'); | |
537 if (first_colon == NULL) { | |
538 if (PrintMiscellaneous && Verbose) { | |
539 warning("expected device specifier in path: %s\n", path); | |
540 } | |
541 return false; | |
542 } | |
543 | |
544 size_t len = (size_t)(first_colon - path); | |
545 assert(len + 2 <= MAX_PATH, "unexpected device specifier length"); | |
546 strncpy(root_path, path, len + 1); | |
547 root_path[len + 1] = '\\'; | |
548 root_path[len + 2] = '\0'; | |
549 | |
550 // check that we have something like "C:\" or "AA:\" | |
551 assert(strlen(root_path) >= 3, "device specifier too short"); | |
552 assert(strchr(root_path, ':') != NULL, "bad device specifier format"); | |
553 assert(strchr(root_path, '\\') != NULL, "bad device specifier format"); | |
554 | |
555 DWORD maxpath; | |
556 DWORD flags; | |
557 | |
558 if (!GetVolumeInformation(root_path, NULL, 0, NULL, &maxpath, | |
559 &flags, fs_type, MAX_PATH)) { | |
560 // we can't get information about the volume, so assume unsafe. | |
561 if (PrintMiscellaneous && Verbose) { | |
562 warning("could not get device information for %s: " | |
563 " path = %s: lasterror = %d\n", | |
564 root_path, path, GetLastError()); | |
565 } | |
566 return false; | |
567 } | |
568 | |
569 if ((flags & FS_PERSISTENT_ACLS) == 0) { | |
570 // file system doesn't support ACLs, declare file system unsafe | |
571 if (PrintMiscellaneous && Verbose) { | |
572 warning("file system type %s on device %s does not support" | |
573 " ACLs\n", fs_type, root_path); | |
574 } | |
575 return false; | |
576 } | |
577 | |
578 if ((flags & FS_VOL_IS_COMPRESSED) != 0) { | |
579 // file system is compressed, declare file system unsafe | |
580 if (PrintMiscellaneous && Verbose) { | |
581 warning("file system type %s on device %s is compressed\n", | |
582 fs_type, root_path); | |
583 } | |
584 return false; | |
585 } | |
586 | |
587 return true; | |
588 } | |
589 | |
590 // cleanup stale shared memory resources | |
591 // | |
592 // This method attempts to remove all stale shared memory files in | |
593 // the named user temporary directory. It scans the named directory | |
594 // for files matching the pattern ^$[0-9]*$. For each file found, the | |
595 // process id is extracted from the file name and a test is run to | |
596 // determine if the process is alive. If the process is not alive, | |
597 // any stale file resources are removed. | |
598 // | |
599 static void cleanup_sharedmem_resources(const char* dirname) { | |
600 | |
601 // open the user temp directory | |
602 DIR* dirp = os::opendir(dirname); | |
603 | |
604 if (dirp == NULL) { | |
605 // directory doesn't exist, so there is nothing to cleanup | |
606 return; | |
607 } | |
608 | |
609 if (!is_directory_secure(dirname)) { | |
610 // the directory is not secure, don't attempt any cleanup | |
611 return; | |
612 } | |
613 | |
614 // for each entry in the directory that matches the expected file | |
615 // name pattern, determine if the file resources are stale and if | |
616 // so, remove the file resources. Note, instrumented HotSpot processes | |
617 // for this user may start and/or terminate during this search and | |
618 // remove or create new files in this directory. The behavior of this | |
619 // loop under these conditions is dependent upon the implementation of | |
620 // opendir/readdir. | |
621 // | |
622 struct dirent* entry; | |
623 char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname)); | |
624 errno = 0; | |
625 while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) { | |
626 | |
627 int pid = filename_to_pid(entry->d_name); | |
628 | |
629 if (pid == 0) { | |
630 | |
631 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) { | |
632 | |
633 // attempt to remove all unexpected files, except "." and ".." | |
634 remove_file(dirname, entry->d_name); | |
635 } | |
636 | |
637 errno = 0; | |
638 continue; | |
639 } | |
640 | |
641 // we now have a file name that converts to a valid integer | |
642 // that could represent a process id . if this process id | |
643 // matches the current process id or the process is not running, | |
644 // then remove the stale file resources. | |
645 // | |
646 // process liveness is detected by checking the exit status | |
647 // of the process. if the process id is valid and the exit status | |
648 // indicates that it is still running, the file file resources | |
649 // are not removed. If the process id is invalid, or if we don't | |
650 // have permissions to check the process status, or if the process | |
651 // id is valid and the process has terminated, the the file resources | |
652 // are assumed to be stale and are removed. | |
653 // | |
654 if (pid == os::current_process_id() || !is_alive(pid)) { | |
655 | |
656 // we can only remove the file resources. Any mapped views | |
657 // of the file can only be unmapped by the processes that | |
658 // opened those views and the file mapping object will not | |
659 // get removed until all views are unmapped. | |
660 // | |
661 remove_file(dirname, entry->d_name); | |
662 } | |
663 errno = 0; | |
664 } | |
665 os::closedir(dirp); | |
666 FREE_C_HEAP_ARRAY(char, dbuf); | |
667 } | |
668 | |
669 // create a file mapping object with the requested name, and size | |
670 // from the file represented by the given Handle object | |
671 // | |
672 static HANDLE create_file_mapping(const char* name, HANDLE fh, LPSECURITY_ATTRIBUTES fsa, size_t size) { | |
673 | |
674 DWORD lowSize = (DWORD)size; | |
675 DWORD highSize = 0; | |
676 HANDLE fmh = NULL; | |
677 | |
678 // Create a file mapping object with the given name. This function | |
679 // will grow the file to the specified size. | |
680 // | |
681 fmh = CreateFileMapping( | |
682 fh, /* HANDLE file handle for backing store */ | |
683 fsa, /* LPSECURITY_ATTRIBUTES Not inheritable */ | |
684 PAGE_READWRITE, /* DWORD protections */ | |
685 highSize, /* DWORD High word of max size */ | |
686 lowSize, /* DWORD Low word of max size */ | |
687 name); /* LPCTSTR name for object */ | |
688 | |
689 if (fmh == NULL) { | |
690 if (PrintMiscellaneous && Verbose) { | |
691 warning("CreateFileMapping failed, lasterror = %d\n", GetLastError()); | |
692 } | |
693 return NULL; | |
694 } | |
695 | |
696 if (GetLastError() == ERROR_ALREADY_EXISTS) { | |
697 | |
698 // a stale file mapping object was encountered. This object may be | |
699 // owned by this or some other user and cannot be removed until | |
700 // the other processes either exit or close their mapping objects | |
701 // and/or mapped views of this mapping object. | |
702 // | |
703 if (PrintMiscellaneous && Verbose) { | |
704 warning("file mapping already exists, lasterror = %d\n", GetLastError()); | |
705 } | |
706 | |
707 CloseHandle(fmh); | |
708 return NULL; | |
709 } | |
710 | |
711 return fmh; | |
712 } | |
713 | |
714 | |
715 // method to free the given security descriptor and the contained | |
716 // access control list. | |
717 // | |
718 static void free_security_desc(PSECURITY_DESCRIPTOR pSD) { | |
719 | |
720 BOOL success, exists, isdefault; | |
721 PACL pACL; | |
722 | |
723 if (pSD != NULL) { | |
724 | |
725 // get the access control list from the security descriptor | |
726 success = GetSecurityDescriptorDacl(pSD, &exists, &pACL, &isdefault); | |
727 | |
728 // if an ACL existed and it was not a default acl, then it must | |
729 // be an ACL we enlisted. free the resources. | |
730 // | |
731 if (success && exists && pACL != NULL && !isdefault) { | |
732 FREE_C_HEAP_ARRAY(char, pACL); | |
733 } | |
734 | |
735 // free the security descriptor | |
736 FREE_C_HEAP_ARRAY(char, pSD); | |
737 } | |
738 } | |
739 | |
740 // method to free up a security attributes structure and any | |
741 // contained security descriptors and ACL | |
742 // | |
743 static void free_security_attr(LPSECURITY_ATTRIBUTES lpSA) { | |
744 | |
745 if (lpSA != NULL) { | |
746 // free the contained security descriptor and the ACL | |
747 free_security_desc(lpSA->lpSecurityDescriptor); | |
748 lpSA->lpSecurityDescriptor = NULL; | |
749 | |
750 // free the security attributes structure | |
751 FREE_C_HEAP_ARRAY(char, lpSA); | |
752 } | |
753 } | |
754 | |
755 // get the user SID for the process indicated by the process handle | |
756 // | |
757 static PSID get_user_sid(HANDLE hProcess) { | |
758 | |
759 HANDLE hAccessToken; | |
760 PTOKEN_USER token_buf = NULL; | |
761 DWORD rsize = 0; | |
762 | |
763 if (hProcess == NULL) { | |
764 return NULL; | |
765 } | |
766 | |
767 // get the process token | |
768 if (!OpenProcessToken(hProcess, TOKEN_READ, &hAccessToken)) { | |
769 if (PrintMiscellaneous && Verbose) { | |
770 warning("OpenProcessToken failure: lasterror = %d \n", GetLastError()); | |
771 } | |
772 return NULL; | |
773 } | |
774 | |
775 // determine the size of the token structured needed to retrieve | |
776 // the user token information from the access token. | |
777 // | |
778 if (!GetTokenInformation(hAccessToken, TokenUser, NULL, rsize, &rsize)) { | |
779 DWORD lasterror = GetLastError(); | |
780 if (lasterror != ERROR_INSUFFICIENT_BUFFER) { | |
781 if (PrintMiscellaneous && Verbose) { | |
782 warning("GetTokenInformation failure: lasterror = %d," | |
783 " rsize = %d\n", lasterror, rsize); | |
784 } | |
785 CloseHandle(hAccessToken); | |
786 return NULL; | |
787 } | |
788 } | |
789 | |
790 token_buf = (PTOKEN_USER) NEW_C_HEAP_ARRAY(char, rsize); | |
791 | |
792 // get the user token information | |
793 if (!GetTokenInformation(hAccessToken, TokenUser, token_buf, rsize, &rsize)) { | |
794 if (PrintMiscellaneous && Verbose) { | |
795 warning("GetTokenInformation failure: lasterror = %d," | |
796 " rsize = %d\n", GetLastError(), rsize); | |
797 } | |
798 FREE_C_HEAP_ARRAY(char, token_buf); | |
799 CloseHandle(hAccessToken); | |
800 return NULL; | |
801 } | |
802 | |
803 DWORD nbytes = GetLengthSid(token_buf->User.Sid); | |
804 PSID pSID = NEW_C_HEAP_ARRAY(char, nbytes); | |
805 | |
806 if (!CopySid(nbytes, pSID, token_buf->User.Sid)) { | |
807 if (PrintMiscellaneous && Verbose) { | |
808 warning("GetTokenInformation failure: lasterror = %d," | |
809 " rsize = %d\n", GetLastError(), rsize); | |
810 } | |
811 FREE_C_HEAP_ARRAY(char, token_buf); | |
812 FREE_C_HEAP_ARRAY(char, pSID); | |
813 CloseHandle(hAccessToken); | |
814 return NULL; | |
815 } | |
816 | |
817 // close the access token. | |
818 CloseHandle(hAccessToken); | |
819 FREE_C_HEAP_ARRAY(char, token_buf); | |
820 | |
821 return pSID; | |
822 } | |
823 | |
824 // structure used to consolidate access control entry information | |
825 // | |
826 typedef struct ace_data { | |
827 PSID pSid; // SID of the ACE | |
828 DWORD mask; // mask for the ACE | |
829 } ace_data_t; | |
830 | |
831 | |
832 // method to add an allow access control entry with the access rights | |
833 // indicated in mask for the principal indicated in SID to the given | |
834 // security descriptor. Much of the DACL handling was adapted from | |
835 // the example provided here: | |
836 // http://support.microsoft.com/kb/102102/EN-US/ | |
837 // | |
838 | |
839 static bool add_allow_aces(PSECURITY_DESCRIPTOR pSD, | |
840 ace_data_t aces[], int ace_count) { | |
841 PACL newACL = NULL; | |
842 PACL oldACL = NULL; | |
843 | |
844 if (pSD == NULL) { | |
845 return false; | |
846 } | |
847 | |
848 BOOL exists, isdefault; | |
849 | |
850 // retrieve any existing access control list. | |
851 if (!GetSecurityDescriptorDacl(pSD, &exists, &oldACL, &isdefault)) { | |
852 if (PrintMiscellaneous && Verbose) { | |
853 warning("GetSecurityDescriptor failure: lasterror = %d \n", | |
854 GetLastError()); | |
855 } | |
856 return false; | |
857 } | |
858 | |
859 // get the size of the DACL | |
860 ACL_SIZE_INFORMATION aclinfo; | |
861 | |
862 // GetSecurityDescriptorDacl may return true value for exists (lpbDaclPresent) | |
863 // while oldACL is NULL for some case. | |
864 if (oldACL == NULL) { | |
865 exists = FALSE; | |
866 } | |
867 | |
868 if (exists) { | |
869 if (!GetAclInformation(oldACL, &aclinfo, | |
870 sizeof(ACL_SIZE_INFORMATION), | |
871 AclSizeInformation)) { | |
872 if (PrintMiscellaneous && Verbose) { | |
873 warning("GetAclInformation failure: lasterror = %d \n", GetLastError()); | |
874 return false; | |
875 } | |
876 } | |
877 } else { | |
878 aclinfo.AceCount = 0; // assume NULL DACL | |
879 aclinfo.AclBytesFree = 0; | |
880 aclinfo.AclBytesInUse = sizeof(ACL); | |
881 } | |
882 | |
883 // compute the size needed for the new ACL | |
884 // initial size of ACL is sum of the following: | |
885 // * size of ACL structure. | |
886 // * size of each ACE structure that ACL is to contain minus the sid | |
887 // sidStart member (DWORD) of the ACE. | |
888 // * length of the SID that each ACE is to contain. | |
889 DWORD newACLsize = aclinfo.AclBytesInUse + | |
890 (sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD)) * ace_count; | |
891 for (int i = 0; i < ace_count; i++) { | |
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892 assert(aces[i].pSid != 0, "pSid should not be 0"); |
0 | 893 newACLsize += GetLengthSid(aces[i].pSid); |
894 } | |
895 | |
896 // create the new ACL | |
897 newACL = (PACL) NEW_C_HEAP_ARRAY(char, newACLsize); | |
898 | |
899 if (!InitializeAcl(newACL, newACLsize, ACL_REVISION)) { | |
900 if (PrintMiscellaneous && Verbose) { | |
901 warning("InitializeAcl failure: lasterror = %d \n", GetLastError()); | |
902 } | |
903 FREE_C_HEAP_ARRAY(char, newACL); | |
904 return false; | |
905 } | |
906 | |
907 unsigned int ace_index = 0; | |
908 // copy any existing ACEs from the old ACL (if any) to the new ACL. | |
909 if (aclinfo.AceCount != 0) { | |
910 while (ace_index < aclinfo.AceCount) { | |
911 LPVOID ace; | |
912 if (!GetAce(oldACL, ace_index, &ace)) { | |
913 if (PrintMiscellaneous && Verbose) { | |
914 warning("InitializeAcl failure: lasterror = %d \n", GetLastError()); | |
915 } | |
916 FREE_C_HEAP_ARRAY(char, newACL); | |
917 return false; | |
918 } | |
919 if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceFlags && INHERITED_ACE) { | |
920 // this is an inherited, allowed ACE; break from loop so we can | |
921 // add the new access allowed, non-inherited ACE in the correct | |
922 // position, immediately following all non-inherited ACEs. | |
923 break; | |
924 } | |
925 | |
926 // determine if the SID of this ACE matches any of the SIDs | |
927 // for which we plan to set ACEs. | |
928 int matches = 0; | |
929 for (int i = 0; i < ace_count; i++) { | |
930 if (EqualSid(aces[i].pSid, &(((ACCESS_ALLOWED_ACE *)ace)->SidStart))) { | |
931 matches++; | |
932 break; | |
933 } | |
934 } | |
935 | |
936 // if there are no SID matches, then add this existing ACE to the new ACL | |
937 if (matches == 0) { | |
938 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace, | |
939 ((PACE_HEADER)ace)->AceSize)) { | |
940 if (PrintMiscellaneous && Verbose) { | |
941 warning("AddAce failure: lasterror = %d \n", GetLastError()); | |
942 } | |
943 FREE_C_HEAP_ARRAY(char, newACL); | |
944 return false; | |
945 } | |
946 } | |
947 ace_index++; | |
948 } | |
949 } | |
950 | |
951 // add the passed-in access control entries to the new ACL | |
952 for (int i = 0; i < ace_count; i++) { | |
953 if (!AddAccessAllowedAce(newACL, ACL_REVISION, | |
954 aces[i].mask, aces[i].pSid)) { | |
955 if (PrintMiscellaneous && Verbose) { | |
956 warning("AddAccessAllowedAce failure: lasterror = %d \n", | |
957 GetLastError()); | |
958 } | |
959 FREE_C_HEAP_ARRAY(char, newACL); | |
960 return false; | |
961 } | |
962 } | |
963 | |
964 // now copy the rest of the inherited ACEs from the old ACL | |
965 if (aclinfo.AceCount != 0) { | |
966 // picking up at ace_index, where we left off in the | |
967 // previous ace_index loop | |
968 while (ace_index < aclinfo.AceCount) { | |
969 LPVOID ace; | |
970 if (!GetAce(oldACL, ace_index, &ace)) { | |
971 if (PrintMiscellaneous && Verbose) { | |
972 warning("InitializeAcl failure: lasterror = %d \n", GetLastError()); | |
973 } | |
974 FREE_C_HEAP_ARRAY(char, newACL); | |
975 return false; | |
976 } | |
977 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace, | |
978 ((PACE_HEADER)ace)->AceSize)) { | |
979 if (PrintMiscellaneous && Verbose) { | |
980 warning("AddAce failure: lasterror = %d \n", GetLastError()); | |
981 } | |
982 FREE_C_HEAP_ARRAY(char, newACL); | |
983 return false; | |
984 } | |
985 ace_index++; | |
986 } | |
987 } | |
988 | |
989 // add the new ACL to the security descriptor. | |
990 if (!SetSecurityDescriptorDacl(pSD, TRUE, newACL, FALSE)) { | |
991 if (PrintMiscellaneous && Verbose) { | |
992 warning("SetSecurityDescriptorDacl failure:" | |
993 " lasterror = %d \n", GetLastError()); | |
994 } | |
995 FREE_C_HEAP_ARRAY(char, newACL); | |
996 return false; | |
997 } | |
998 | |
605 | 999 // if running on windows 2000 or later, set the automatic inheritance |
0 | 1000 // control flags. |
1001 SetSecurityDescriptorControlFnPtr _SetSecurityDescriptorControl; | |
1002 _SetSecurityDescriptorControl = (SetSecurityDescriptorControlFnPtr) | |
1003 GetProcAddress(GetModuleHandle(TEXT("advapi32.dll")), | |
1004 "SetSecurityDescriptorControl"); | |
1005 | |
1006 if (_SetSecurityDescriptorControl != NULL) { | |
605 | 1007 // We do not want to further propagate inherited DACLs, so making them |
0 | 1008 // protected prevents that. |
1009 if (!_SetSecurityDescriptorControl(pSD, SE_DACL_PROTECTED, | |
1010 SE_DACL_PROTECTED)) { | |
1011 if (PrintMiscellaneous && Verbose) { | |
1012 warning("SetSecurityDescriptorControl failure:" | |
1013 " lasterror = %d \n", GetLastError()); | |
1014 } | |
1015 FREE_C_HEAP_ARRAY(char, newACL); | |
1016 return false; | |
1017 } | |
1018 } | |
1019 // Note, the security descriptor maintains a reference to the newACL, not | |
1020 // a copy of it. Therefore, the newACL is not freed here. It is freed when | |
1021 // the security descriptor containing its reference is freed. | |
1022 // | |
1023 return true; | |
1024 } | |
1025 | |
1026 // method to create a security attributes structure, which contains a | |
1027 // security descriptor and an access control list comprised of 0 or more | |
1028 // access control entries. The method take an array of ace_data structures | |
1029 // that indicate the ACE to be added to the security descriptor. | |
1030 // | |
1031 // the caller must free the resources associated with the security | |
1032 // attributes structure created by this method by calling the | |
1033 // free_security_attr() method. | |
1034 // | |
1035 static LPSECURITY_ATTRIBUTES make_security_attr(ace_data_t aces[], int count) { | |
1036 | |
1037 // allocate space for a security descriptor | |
1038 PSECURITY_DESCRIPTOR pSD = (PSECURITY_DESCRIPTOR) | |
1039 NEW_C_HEAP_ARRAY(char, SECURITY_DESCRIPTOR_MIN_LENGTH); | |
1040 | |
1041 // initialize the security descriptor | |
1042 if (!InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION)) { | |
1043 if (PrintMiscellaneous && Verbose) { | |
1044 warning("InitializeSecurityDescriptor failure: " | |
1045 "lasterror = %d \n", GetLastError()); | |
1046 } | |
1047 free_security_desc(pSD); | |
1048 return NULL; | |
1049 } | |
1050 | |
1051 // add the access control entries | |
1052 if (!add_allow_aces(pSD, aces, count)) { | |
1053 free_security_desc(pSD); | |
1054 return NULL; | |
1055 } | |
1056 | |
1057 // allocate and initialize the security attributes structure and | |
1058 // return it to the caller. | |
1059 // | |
1060 LPSECURITY_ATTRIBUTES lpSA = (LPSECURITY_ATTRIBUTES) | |
1061 NEW_C_HEAP_ARRAY(char, sizeof(SECURITY_ATTRIBUTES)); | |
1062 lpSA->nLength = sizeof(SECURITY_ATTRIBUTES); | |
1063 lpSA->lpSecurityDescriptor = pSD; | |
1064 lpSA->bInheritHandle = FALSE; | |
1065 | |
1066 return(lpSA); | |
1067 } | |
1068 | |
1069 // method to create a security attributes structure with a restrictive | |
1070 // access control list that creates a set access rights for the user/owner | |
1071 // of the securable object and a separate set access rights for everyone else. | |
1072 // also provides for full access rights for the administrator group. | |
1073 // | |
1074 // the caller must free the resources associated with the security | |
1075 // attributes structure created by this method by calling the | |
1076 // free_security_attr() method. | |
1077 // | |
1078 | |
1079 static LPSECURITY_ATTRIBUTES make_user_everybody_admin_security_attr( | |
1080 DWORD umask, DWORD emask, DWORD amask) { | |
1081 | |
1082 ace_data_t aces[3]; | |
1083 | |
1084 // initialize the user ace data | |
1085 aces[0].pSid = get_user_sid(GetCurrentProcess()); | |
1086 aces[0].mask = umask; | |
1087 | |
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1088 if (aces[0].pSid == 0) |
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1089 return NULL; |
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1090 |
0 | 1091 // get the well known SID for BUILTIN\Administrators |
1092 PSID administratorsSid = NULL; | |
1093 SID_IDENTIFIER_AUTHORITY SIDAuthAdministrators = SECURITY_NT_AUTHORITY; | |
1094 | |
1095 if (!AllocateAndInitializeSid( &SIDAuthAdministrators, 2, | |
1096 SECURITY_BUILTIN_DOMAIN_RID, | |
1097 DOMAIN_ALIAS_RID_ADMINS, | |
1098 0, 0, 0, 0, 0, 0, &administratorsSid)) { | |
1099 | |
1100 if (PrintMiscellaneous && Verbose) { | |
1101 warning("AllocateAndInitializeSid failure: " | |
1102 "lasterror = %d \n", GetLastError()); | |
1103 } | |
1104 return NULL; | |
1105 } | |
1106 | |
1107 // initialize the ace data for administrator group | |
1108 aces[1].pSid = administratorsSid; | |
1109 aces[1].mask = amask; | |
1110 | |
1111 // get the well known SID for the universal Everybody | |
1112 PSID everybodySid = NULL; | |
1113 SID_IDENTIFIER_AUTHORITY SIDAuthEverybody = SECURITY_WORLD_SID_AUTHORITY; | |
1114 | |
1115 if (!AllocateAndInitializeSid( &SIDAuthEverybody, 1, SECURITY_WORLD_RID, | |
1116 0, 0, 0, 0, 0, 0, 0, &everybodySid)) { | |
1117 | |
1118 if (PrintMiscellaneous && Verbose) { | |
1119 warning("AllocateAndInitializeSid failure: " | |
1120 "lasterror = %d \n", GetLastError()); | |
1121 } | |
1122 return NULL; | |
1123 } | |
1124 | |
1125 // initialize the ace data for everybody else. | |
1126 aces[2].pSid = everybodySid; | |
1127 aces[2].mask = emask; | |
1128 | |
1129 // create a security attributes structure with access control | |
1130 // entries as initialized above. | |
1131 LPSECURITY_ATTRIBUTES lpSA = make_security_attr(aces, 3); | |
1132 FREE_C_HEAP_ARRAY(char, aces[0].pSid); | |
1133 FreeSid(everybodySid); | |
1134 FreeSid(administratorsSid); | |
1135 return(lpSA); | |
1136 } | |
1137 | |
1138 | |
1139 // method to create the security attributes structure for restricting | |
1140 // access to the user temporary directory. | |
1141 // | |
1142 // the caller must free the resources associated with the security | |
1143 // attributes structure created by this method by calling the | |
1144 // free_security_attr() method. | |
1145 // | |
1146 static LPSECURITY_ATTRIBUTES make_tmpdir_security_attr() { | |
1147 | |
1148 // create full access rights for the user/owner of the directory | |
1149 // and read-only access rights for everybody else. This is | |
1150 // effectively equivalent to UNIX 755 permissions on a directory. | |
1151 // | |
1152 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_ALL_ACCESS; | |
1153 DWORD emask = GENERIC_READ | FILE_LIST_DIRECTORY | FILE_TRAVERSE; | |
1154 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS; | |
1155 | |
1156 return make_user_everybody_admin_security_attr(umask, emask, amask); | |
1157 } | |
1158 | |
1159 // method to create the security attributes structure for restricting | |
1160 // access to the shared memory backing store file. | |
1161 // | |
1162 // the caller must free the resources associated with the security | |
1163 // attributes structure created by this method by calling the | |
1164 // free_security_attr() method. | |
1165 // | |
1166 static LPSECURITY_ATTRIBUTES make_file_security_attr() { | |
1167 | |
1168 // create extensive access rights for the user/owner of the file | |
1169 // and attribute read-only access rights for everybody else. This | |
1170 // is effectively equivalent to UNIX 600 permissions on a file. | |
1171 // | |
1172 DWORD umask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS; | |
1173 DWORD emask = STANDARD_RIGHTS_READ | FILE_READ_ATTRIBUTES | | |
1174 FILE_READ_EA | FILE_LIST_DIRECTORY | FILE_TRAVERSE; | |
1175 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS; | |
1176 | |
1177 return make_user_everybody_admin_security_attr(umask, emask, amask); | |
1178 } | |
1179 | |
1180 // method to create the security attributes structure for restricting | |
1181 // access to the name shared memory file mapping object. | |
1182 // | |
1183 // the caller must free the resources associated with the security | |
1184 // attributes structure created by this method by calling the | |
1185 // free_security_attr() method. | |
1186 // | |
1187 static LPSECURITY_ATTRIBUTES make_smo_security_attr() { | |
1188 | |
1189 // create extensive access rights for the user/owner of the shared | |
1190 // memory object and attribute read-only access rights for everybody | |
1191 // else. This is effectively equivalent to UNIX 600 permissions on | |
1192 // on the shared memory object. | |
1193 // | |
1194 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_MAP_ALL_ACCESS; | |
1195 DWORD emask = STANDARD_RIGHTS_READ; // attributes only | |
1196 DWORD amask = STANDARD_RIGHTS_ALL | FILE_MAP_ALL_ACCESS; | |
1197 | |
1198 return make_user_everybody_admin_security_attr(umask, emask, amask); | |
1199 } | |
1200 | |
1201 // make the user specific temporary directory | |
1202 // | |
1203 static bool make_user_tmp_dir(const char* dirname) { | |
1204 | |
1205 | |
1206 LPSECURITY_ATTRIBUTES pDirSA = make_tmpdir_security_attr(); | |
1207 if (pDirSA == NULL) { | |
1208 return false; | |
1209 } | |
1210 | |
1211 | |
1212 // create the directory with the given security attributes | |
1213 if (!CreateDirectory(dirname, pDirSA)) { | |
1214 DWORD lasterror = GetLastError(); | |
1215 if (lasterror == ERROR_ALREADY_EXISTS) { | |
1216 // The directory already exists and was probably created by another | |
1217 // JVM instance. However, this could also be the result of a | |
1218 // deliberate symlink. Verify that the existing directory is safe. | |
1219 // | |
1220 if (!is_directory_secure(dirname)) { | |
1221 // directory is not secure | |
1222 if (PrintMiscellaneous && Verbose) { | |
1223 warning("%s directory is insecure\n", dirname); | |
1224 } | |
1225 return false; | |
1226 } | |
1227 // The administrator should be able to delete this directory. | |
1228 // But the directory created by previous version of JVM may not | |
1229 // have permission for administrators to delete this directory. | |
1230 // So add full permission to the administrator. Also setting new | |
1231 // DACLs might fix the corrupted the DACLs. | |
1232 SECURITY_INFORMATION secInfo = DACL_SECURITY_INFORMATION; | |
1233 if (!SetFileSecurity(dirname, secInfo, pDirSA->lpSecurityDescriptor)) { | |
1234 if (PrintMiscellaneous && Verbose) { | |
1235 lasterror = GetLastError(); | |
1236 warning("SetFileSecurity failed for %s directory. lasterror %d \n", | |
1237 dirname, lasterror); | |
1238 } | |
1239 } | |
1240 } | |
1241 else { | |
1242 if (PrintMiscellaneous && Verbose) { | |
1243 warning("CreateDirectory failed: %d\n", GetLastError()); | |
1244 } | |
1245 return false; | |
1246 } | |
1247 } | |
1248 | |
1249 // free the security attributes structure | |
1250 free_security_attr(pDirSA); | |
1251 | |
1252 return true; | |
1253 } | |
1254 | |
1255 // create the shared memory resources | |
1256 // | |
1257 // This function creates the shared memory resources. This includes | |
1258 // the backing store file and the file mapping shared memory object. | |
1259 // | |
1260 static HANDLE create_sharedmem_resources(const char* dirname, const char* filename, const char* objectname, size_t size) { | |
1261 | |
1262 HANDLE fh = INVALID_HANDLE_VALUE; | |
1263 HANDLE fmh = NULL; | |
1264 | |
1265 | |
1266 // create the security attributes for the backing store file | |
1267 LPSECURITY_ATTRIBUTES lpFileSA = make_file_security_attr(); | |
1268 if (lpFileSA == NULL) { | |
1269 return NULL; | |
1270 } | |
1271 | |
1272 // create the security attributes for the shared memory object | |
1273 LPSECURITY_ATTRIBUTES lpSmoSA = make_smo_security_attr(); | |
1274 if (lpSmoSA == NULL) { | |
1275 free_security_attr(lpFileSA); | |
1276 return NULL; | |
1277 } | |
1278 | |
1279 // create the user temporary directory | |
1280 if (!make_user_tmp_dir(dirname)) { | |
1281 // could not make/find the directory or the found directory | |
1282 // was not secure | |
1283 return NULL; | |
1284 } | |
1285 | |
1286 // Create the file - the FILE_FLAG_DELETE_ON_CLOSE flag allows the | |
1287 // file to be deleted by the last process that closes its handle to | |
1288 // the file. This is important as the apis do not allow a terminating | |
1289 // JVM being monitored by another process to remove the file name. | |
1290 // | |
1291 // the FILE_SHARE_DELETE share mode is valid only in winnt | |
1292 // | |
1293 fh = CreateFile( | |
1294 filename, /* LPCTSTR file name */ | |
1295 | |
1296 GENERIC_READ|GENERIC_WRITE, /* DWORD desired access */ | |
1297 | |
1298 (os::win32::is_nt() ? FILE_SHARE_DELETE : 0)| | |
1299 FILE_SHARE_READ, /* DWORD share mode, future READONLY | |
1300 * open operations allowed | |
1301 */ | |
1302 lpFileSA, /* LPSECURITY security attributes */ | |
1303 CREATE_ALWAYS, /* DWORD creation disposition | |
1304 * create file, if it already | |
1305 * exists, overwrite it. | |
1306 */ | |
1307 FILE_FLAG_DELETE_ON_CLOSE, /* DWORD flags and attributes */ | |
1308 | |
1309 NULL); /* HANDLE template file access */ | |
1310 | |
1311 free_security_attr(lpFileSA); | |
1312 | |
1313 if (fh == INVALID_HANDLE_VALUE) { | |
1314 DWORD lasterror = GetLastError(); | |
1315 if (PrintMiscellaneous && Verbose) { | |
1316 warning("could not create file %s: %d\n", filename, lasterror); | |
1317 } | |
1318 return NULL; | |
1319 } | |
1320 | |
1321 // try to create the file mapping | |
1322 fmh = create_file_mapping(objectname, fh, lpSmoSA, size); | |
1323 | |
1324 free_security_attr(lpSmoSA); | |
1325 | |
1326 if (fmh == NULL) { | |
1327 // closing the file handle here will decrement the reference count | |
1328 // on the file. When all processes accessing the file close their | |
1329 // handle to it, the reference count will decrement to 0 and the | |
1330 // OS will delete the file. These semantics are requested by the | |
1331 // FILE_FLAG_DELETE_ON_CLOSE flag in CreateFile call above. | |
1332 CloseHandle(fh); | |
1333 fh = NULL; | |
1334 return NULL; | |
1335 } | |
1336 | |
1337 // the file has been successfully created and the file mapping | |
1338 // object has been created. | |
1339 sharedmem_fileHandle = fh; | |
1340 sharedmem_fileName = strdup(filename); | |
1341 | |
1342 return fmh; | |
1343 } | |
1344 | |
1345 // open the shared memory object for the given vmid. | |
1346 // | |
1347 static HANDLE open_sharedmem_object(const char* objectname, DWORD ofm_access, TRAPS) { | |
1348 | |
1349 HANDLE fmh; | |
1350 | |
1351 // open the file mapping with the requested mode | |
1352 fmh = OpenFileMapping( | |
1353 ofm_access, /* DWORD access mode */ | |
1354 FALSE, /* BOOL inherit flag - Do not allow inherit */ | |
1355 objectname); /* name for object */ | |
1356 | |
1357 if (fmh == NULL) { | |
1358 if (PrintMiscellaneous && Verbose) { | |
1359 warning("OpenFileMapping failed for shared memory object %s:" | |
1360 " lasterror = %d\n", objectname, GetLastError()); | |
1361 } | |
1362 THROW_MSG_(vmSymbols::java_lang_Exception(), | |
1363 "Could not open PerfMemory", INVALID_HANDLE_VALUE); | |
1364 } | |
1365 | |
1366 return fmh;; | |
1367 } | |
1368 | |
1369 // create a named shared memory region | |
1370 // | |
1371 // On Win32, a named shared memory object has a name space that | |
1372 // is independent of the file system name space. Shared memory object, | |
1373 // or more precisely, file mapping objects, provide no mechanism to | |
1374 // inquire the size of the memory region. There is also no api to | |
1375 // enumerate the memory regions for various processes. | |
1376 // | |
1377 // This implementation utilizes the shared memory name space in parallel | |
1378 // with the file system name space. This allows us to determine the | |
1379 // size of the shared memory region from the size of the file and it | |
1380 // allows us to provide a common, file system based name space for | |
1381 // shared memory across platforms. | |
1382 // | |
1383 static char* mapping_create_shared(size_t size) { | |
1384 | |
1385 void *mapAddress; | |
1386 int vmid = os::current_process_id(); | |
1387 | |
1388 // get the name of the user associated with this process | |
1389 char* user = get_user_name(); | |
1390 | |
1391 if (user == NULL) { | |
1392 return NULL; | |
1393 } | |
1394 | |
1395 // construct the name of the user specific temporary directory | |
1396 char* dirname = get_user_tmp_dir(user); | |
1397 | |
1398 // check that the file system is secure - i.e. it supports ACLs. | |
1399 if (!is_filesystem_secure(dirname)) { | |
1400 return NULL; | |
1401 } | |
1402 | |
1403 // create the names of the backing store files and for the | |
1404 // share memory object. | |
1405 // | |
1406 char* filename = get_sharedmem_filename(dirname, vmid); | |
1407 char* objectname = get_sharedmem_objectname(user, vmid); | |
1408 | |
1409 // cleanup any stale shared memory resources | |
1410 cleanup_sharedmem_resources(dirname); | |
1411 | |
1412 assert(((size != 0) && (size % os::vm_page_size() == 0)), | |
1413 "unexpected PerfMemry region size"); | |
1414 | |
1415 FREE_C_HEAP_ARRAY(char, user); | |
1416 | |
1417 // create the shared memory resources | |
1418 sharedmem_fileMapHandle = | |
1419 create_sharedmem_resources(dirname, filename, objectname, size); | |
1420 | |
1421 FREE_C_HEAP_ARRAY(char, filename); | |
1422 FREE_C_HEAP_ARRAY(char, objectname); | |
1423 FREE_C_HEAP_ARRAY(char, dirname); | |
1424 | |
1425 if (sharedmem_fileMapHandle == NULL) { | |
1426 return NULL; | |
1427 } | |
1428 | |
1429 // map the file into the address space | |
1430 mapAddress = MapViewOfFile( | |
1431 sharedmem_fileMapHandle, /* HANDLE = file mapping object */ | |
1432 FILE_MAP_ALL_ACCESS, /* DWORD access flags */ | |
1433 0, /* DWORD High word of offset */ | |
1434 0, /* DWORD Low word of offset */ | |
1435 (DWORD)size); /* DWORD Number of bytes to map */ | |
1436 | |
1437 if (mapAddress == NULL) { | |
1438 if (PrintMiscellaneous && Verbose) { | |
1439 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError()); | |
1440 } | |
1441 CloseHandle(sharedmem_fileMapHandle); | |
1442 sharedmem_fileMapHandle = NULL; | |
1443 return NULL; | |
1444 } | |
1445 | |
1446 // clear the shared memory region | |
1447 (void)memset(mapAddress, '\0', size); | |
1448 | |
1449 return (char*) mapAddress; | |
1450 } | |
1451 | |
1452 // this method deletes the file mapping object. | |
1453 // | |
1454 static void delete_file_mapping(char* addr, size_t size) { | |
1455 | |
1456 // cleanup the persistent shared memory resources. since DestroyJavaVM does | |
1457 // not support unloading of the JVM, unmapping of the memory resource is not | |
1458 // performed. The memory will be reclaimed by the OS upon termination of all | |
1459 // processes mapping the resource. The file mapping handle and the file | |
1460 // handle are closed here to expedite the remove of the file by the OS. The | |
1461 // file is not removed directly because it was created with | |
1462 // FILE_FLAG_DELETE_ON_CLOSE semantics and any attempt to remove it would | |
1463 // be unsuccessful. | |
1464 | |
1465 // close the fileMapHandle. the file mapping will still be retained | |
1466 // by the OS as long as any other JVM processes has an open file mapping | |
1467 // handle or a mapped view of the file. | |
1468 // | |
1469 if (sharedmem_fileMapHandle != NULL) { | |
1470 CloseHandle(sharedmem_fileMapHandle); | |
1471 sharedmem_fileMapHandle = NULL; | |
1472 } | |
1473 | |
1474 // close the file handle. This will decrement the reference count on the | |
1475 // backing store file. When the reference count decrements to 0, the OS | |
1476 // will delete the file. These semantics apply because the file was | |
1477 // created with the FILE_FLAG_DELETE_ON_CLOSE flag. | |
1478 // | |
1479 if (sharedmem_fileHandle != INVALID_HANDLE_VALUE) { | |
1480 CloseHandle(sharedmem_fileHandle); | |
1481 sharedmem_fileHandle = INVALID_HANDLE_VALUE; | |
1482 } | |
1483 } | |
1484 | |
1485 // this method determines the size of the shared memory file | |
1486 // | |
1487 static size_t sharedmem_filesize(const char* filename, TRAPS) { | |
1488 | |
1489 struct stat statbuf; | |
1490 | |
1491 // get the file size | |
1492 // | |
1493 // on win95/98/me, _stat returns a file size of 0 bytes, but on | |
1494 // winnt/2k the appropriate file size is returned. support for | |
1495 // the sharable aspects of performance counters was abandonded | |
1496 // on the non-nt win32 platforms due to this and other api | |
1497 // inconsistencies | |
1498 // | |
1499 if (::stat(filename, &statbuf) == OS_ERR) { | |
1500 if (PrintMiscellaneous && Verbose) { | |
1501 warning("stat %s failed: %s\n", filename, strerror(errno)); | |
1502 } | |
1503 THROW_MSG_0(vmSymbols::java_io_IOException(), | |
1504 "Could not determine PerfMemory size"); | |
1505 } | |
1506 | |
1507 if ((statbuf.st_size == 0) || (statbuf.st_size % os::vm_page_size() != 0)) { | |
1508 if (PrintMiscellaneous && Verbose) { | |
1509 warning("unexpected file size: size = " SIZE_FORMAT "\n", | |
1510 statbuf.st_size); | |
1511 } | |
1512 THROW_MSG_0(vmSymbols::java_lang_Exception(), | |
1513 "Invalid PerfMemory size"); | |
1514 } | |
1515 | |
1516 return statbuf.st_size; | |
1517 } | |
1518 | |
1519 // this method opens a file mapping object and maps the object | |
1520 // into the address space of the process | |
1521 // | |
1522 static void open_file_mapping(const char* user, int vmid, | |
1523 PerfMemory::PerfMemoryMode mode, | |
1524 char** addrp, size_t* sizep, TRAPS) { | |
1525 | |
1526 ResourceMark rm; | |
1527 | |
1528 void *mapAddress = 0; | |
1529 size_t size; | |
1530 HANDLE fmh; | |
1531 DWORD ofm_access; | |
1532 DWORD mv_access; | |
1533 const char* luser = NULL; | |
1534 | |
1535 if (mode == PerfMemory::PERF_MODE_RO) { | |
1536 ofm_access = FILE_MAP_READ; | |
1537 mv_access = FILE_MAP_READ; | |
1538 } | |
1539 else if (mode == PerfMemory::PERF_MODE_RW) { | |
1540 #ifdef LATER | |
1541 ofm_access = FILE_MAP_READ | FILE_MAP_WRITE; | |
1542 mv_access = FILE_MAP_READ | FILE_MAP_WRITE; | |
1543 #else | |
1544 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
1545 "Unsupported access mode"); | |
1546 #endif | |
1547 } | |
1548 else { | |
1549 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
1550 "Illegal access mode"); | |
1551 } | |
1552 | |
1553 // if a user name wasn't specified, then find the user name for | |
1554 // the owner of the target vm. | |
1555 if (user == NULL || strlen(user) == 0) { | |
1556 luser = get_user_name(vmid); | |
1557 } | |
1558 else { | |
1559 luser = user; | |
1560 } | |
1561 | |
1562 if (luser == NULL) { | |
1563 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
1564 "Could not map vmid to user name"); | |
1565 } | |
1566 | |
1567 // get the names for the resources for the target vm | |
1568 char* dirname = get_user_tmp_dir(luser); | |
1569 | |
1570 // since we don't follow symbolic links when creating the backing | |
1571 // store file, we also don't following them when attaching | |
1572 // | |
1573 if (!is_directory_secure(dirname)) { | |
1574 FREE_C_HEAP_ARRAY(char, dirname); | |
1575 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
1576 "Process not found"); | |
1577 } | |
1578 | |
1579 char* filename = get_sharedmem_filename(dirname, vmid); | |
1580 char* objectname = get_sharedmem_objectname(luser, vmid); | |
1581 | |
1582 // copy heap memory to resource memory. the objectname and | |
1583 // filename are passed to methods that may throw exceptions. | |
1584 // using resource arrays for these names prevents the leaks | |
1585 // that would otherwise occur. | |
1586 // | |
1587 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1); | |
1588 char* robjectname = NEW_RESOURCE_ARRAY(char, strlen(objectname) + 1); | |
1589 strcpy(rfilename, filename); | |
1590 strcpy(robjectname, objectname); | |
1591 | |
1592 // free the c heap resources that are no longer needed | |
1593 if (luser != user) FREE_C_HEAP_ARRAY(char, luser); | |
1594 FREE_C_HEAP_ARRAY(char, dirname); | |
1595 FREE_C_HEAP_ARRAY(char, filename); | |
1596 FREE_C_HEAP_ARRAY(char, objectname); | |
1597 | |
1598 if (*sizep == 0) { | |
1599 size = sharedmem_filesize(rfilename, CHECK); | |
1600 assert(size != 0, "unexpected size"); | |
1601 } | |
1602 | |
1603 // Open the file mapping object with the given name | |
1604 fmh = open_sharedmem_object(robjectname, ofm_access, CHECK); | |
1605 | |
1606 assert(fmh != INVALID_HANDLE_VALUE, "unexpected handle value"); | |
1607 | |
1608 // map the entire file into the address space | |
1609 mapAddress = MapViewOfFile( | |
1610 fmh, /* HANDLE Handle of file mapping object */ | |
1611 mv_access, /* DWORD access flags */ | |
1612 0, /* DWORD High word of offset */ | |
1613 0, /* DWORD Low word of offset */ | |
1614 size); /* DWORD Number of bytes to map */ | |
1615 | |
1616 if (mapAddress == NULL) { | |
1617 if (PrintMiscellaneous && Verbose) { | |
1618 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError()); | |
1619 } | |
1620 CloseHandle(fmh); | |
1621 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(), | |
1622 "Could not map PerfMemory"); | |
1623 } | |
1624 | |
1625 *addrp = (char*)mapAddress; | |
1626 *sizep = size; | |
1627 | |
1628 // File mapping object can be closed at this time without | |
1629 // invalidating the mapped view of the file | |
1630 CloseHandle(fmh); | |
1631 | |
1632 if (PerfTraceMemOps) { | |
1633 tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at " | |
1634 INTPTR_FORMAT "\n", size, vmid, mapAddress); | |
1635 } | |
1636 } | |
1637 | |
1638 // this method unmaps the the mapped view of the the | |
1639 // file mapping object. | |
1640 // | |
1641 static void remove_file_mapping(char* addr) { | |
1642 | |
1643 // the file mapping object was closed in open_file_mapping() | |
1644 // after the file map view was created. We only need to | |
1645 // unmap the file view here. | |
1646 UnmapViewOfFile(addr); | |
1647 } | |
1648 | |
1649 // create the PerfData memory region in shared memory. | |
1650 static char* create_shared_memory(size_t size) { | |
1651 | |
1652 return mapping_create_shared(size); | |
1653 } | |
1654 | |
1655 // release a named, shared memory region | |
1656 // | |
1657 void delete_shared_memory(char* addr, size_t size) { | |
1658 | |
1659 delete_file_mapping(addr, size); | |
1660 } | |
1661 | |
1662 | |
1663 | |
1664 | |
1665 // create the PerfData memory region | |
1666 // | |
1667 // This method creates the memory region used to store performance | |
1668 // data for the JVM. The memory may be created in standard or | |
1669 // shared memory. | |
1670 // | |
1671 void PerfMemory::create_memory_region(size_t size) { | |
1672 | |
1673 if (PerfDisableSharedMem || !os::win32::is_nt()) { | |
1674 // do not share the memory for the performance data. | |
1675 PerfDisableSharedMem = true; | |
1676 _start = create_standard_memory(size); | |
1677 } | |
1678 else { | |
1679 _start = create_shared_memory(size); | |
1680 if (_start == NULL) { | |
1681 | |
1682 // creation of the shared memory region failed, attempt | |
1683 // to create a contiguous, non-shared memory region instead. | |
1684 // | |
1685 if (PrintMiscellaneous && Verbose) { | |
1686 warning("Reverting to non-shared PerfMemory region.\n"); | |
1687 } | |
1688 PerfDisableSharedMem = true; | |
1689 _start = create_standard_memory(size); | |
1690 } | |
1691 } | |
1692 | |
1693 if (_start != NULL) _capacity = size; | |
1694 | |
1695 } | |
1696 | |
1697 // delete the PerfData memory region | |
1698 // | |
1699 // This method deletes the memory region used to store performance | |
1700 // data for the JVM. The memory region indicated by the <address, size> | |
1701 // tuple will be inaccessible after a call to this method. | |
1702 // | |
1703 void PerfMemory::delete_memory_region() { | |
1704 | |
1705 assert((start() != NULL && capacity() > 0), "verify proper state"); | |
1706 | |
1707 // If user specifies PerfDataSaveFile, it will save the performance data | |
1708 // to the specified file name no matter whether PerfDataSaveToFile is specified | |
1709 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag | |
1710 // -XX:+PerfDataSaveToFile. | |
1711 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) { | |
1712 save_memory_to_file(start(), capacity()); | |
1713 } | |
1714 | |
1715 if (PerfDisableSharedMem) { | |
1716 delete_standard_memory(start(), capacity()); | |
1717 } | |
1718 else { | |
1719 delete_shared_memory(start(), capacity()); | |
1720 } | |
1721 } | |
1722 | |
1723 // attach to the PerfData memory region for another JVM | |
1724 // | |
1725 // This method returns an <address, size> tuple that points to | |
1726 // a memory buffer that is kept reasonably synchronized with | |
1727 // the PerfData memory region for the indicated JVM. This | |
1728 // buffer may be kept in synchronization via shared memory | |
1729 // or some other mechanism that keeps the buffer updated. | |
1730 // | |
1731 // If the JVM chooses not to support the attachability feature, | |
1732 // this method should throw an UnsupportedOperation exception. | |
1733 // | |
1734 // This implementation utilizes named shared memory to map | |
1735 // the indicated process's PerfData memory region into this JVMs | |
1736 // address space. | |
1737 // | |
1738 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, | |
1739 char** addrp, size_t* sizep, TRAPS) { | |
1740 | |
1741 if (vmid == 0 || vmid == os::current_process_id()) { | |
1742 *addrp = start(); | |
1743 *sizep = capacity(); | |
1744 return; | |
1745 } | |
1746 | |
1747 open_file_mapping(user, vmid, mode, addrp, sizep, CHECK); | |
1748 } | |
1749 | |
1750 // detach from the PerfData memory region of another JVM | |
1751 // | |
1752 // This method detaches the PerfData memory region of another | |
1753 // JVM, specified as an <address, size> tuple of a buffer | |
1754 // in this process's address space. This method may perform | |
1755 // arbitrary actions to accomplish the detachment. The memory | |
1756 // region specified by <address, size> will be inaccessible after | |
1757 // a call to this method. | |
1758 // | |
1759 // If the JVM chooses not to support the attachability feature, | |
1760 // this method should throw an UnsupportedOperation exception. | |
1761 // | |
1762 // This implementation utilizes named shared memory to detach | |
1763 // the indicated process's PerfData memory region from this | |
1764 // process's address space. | |
1765 // | |
1766 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) { | |
1767 | |
1768 assert(addr != 0, "address sanity check"); | |
1769 assert(bytes > 0, "capacity sanity check"); | |
1770 | |
1771 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) { | |
1772 // prevent accidental detachment of this process's PerfMemory region | |
1773 return; | |
1774 } | |
1775 | |
1776 remove_file_mapping(addr); | |
1777 } | |
1778 | |
1779 char* PerfMemory::backing_store_filename() { | |
1780 return sharedmem_fileName; | |
1781 } |